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Sample records for distributed catchment modeling

  1. Inverse distributed hydrological modelling of alpine catchments

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    H. Kunstmann

    2005-12-01

    Full Text Available Even in physically based distributed hydrological models, various remaining parameters must be estimated for each sub-catchment. This can involve tremendous effort, especially when the number of sub-catchments is large and the applied hydrological model is computationally expensive. Automatic parameter estimation tools can significantly facilitate the calibration process. Hence, we combined the nonlinear parameter estimation tool PEST with the distributed hydrological model WaSiM. PEST is based on the Gauss-Marquardt-Levenberg method, a gradient-based nonlinear parameter estimation algorithm. WaSiM is a fully distributed hydrological model using physically based algorithms for most of the process descriptions.

    WaSiM was applied to the alpine/prealpine Ammer River catchment (southern Germany, 710 km2 in a 100×100 m2 horizontal resolution. The catchment is heterogeneous in terms of geology, pedology and land use and shows a complex orography (the difference of elevation is around 1600 m. Using the developed PEST-WaSiM interface, the hydrological model was calibrated by comparing simulated and observed runoff at eight gauges for the hydrologic year 1997 and validated for the hydrologic year 1993. For each sub-catchment four parameters had to be calibrated: the recession constants of direct runoff and interflow, the drainage density, and the hydraulic conductivity of the uppermost aquifer. Additionally, five snowmelt specific parameters were adjusted for the entire catchment. Altogether, 37 parameters had to be calibrated. Additional a priori information (e.g. from flood hydrograph analysis narrowed the parameter space of the solutions and improved the non-uniqueness of the fitted values. A reasonable quality of fit was achieved. Discrepancies between modelled and observed runoff were also due to the small number of meteorological stations and corresponding interpolation artefacts in the orographically complex

  2. Modeling 3D soil and sediment distributions for assessing catchment structure and hydrological feedbacks

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    Maurer, Thomas; Brück, Yasemine; Hinz, Christoph; Gerke, Horst H.

    2015-04-01

    Structural heterogeneity, namely the spatial distribution of soils and sediments (represented by mineral particles), characterizes catchment hydrological behavior. In natural catchments, local geology and the specific geomorphic processes determine the characteristics and spatial distribution of structures. In constructed catchments, structural features are determined primarily by the construction processes and the geological origin of the parent material. Objectives are scenarios of 3D catchment structures in form of complete 3D description of soil hydraulic properties generated from the knowledge of the formation processes. The constructed hydrological catchment 'Hühnerwasser' (Lower Lusatia, Brandenburg, Germany) was used for the calibration and validation of model results due to its well-known conditions. For the modelling of structural features, a structure generator was used to model i) quasi-deterministic sediment distributions using input data from a geological model of the parent material excavation site; ii) sediment distributions that are conditioned to measurement data from soil sampling; and iii) stochastic component sediment distributions. All three approaches allow a randomization within definable limits. Furthermore, the spoil cone / spoil ridge orientation, internal layering, surface compaction and internal spoil cone compaction were modified. These generated structural models were incorporated in a gridded 3D volume model constructed with the GOCAD software. For selected scenarios, the impact of structure variation was assessed by hydrological modelling with HYDRUS 2D/3D software. For that purpose, 3D distributions of soil hydraulic properties were estimated based on generated sediment properties using adapted pedotransfer functions. Results from the hydrological model were compared them to measured discharges from the catchment. The impact of structural feature variation on flow behaviour was analysed by comparing different simulation scenarios

  3. Sediment distribution modeling for evaluating the impact of initial structure on catchment hydrological behaviour

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    Maurer, T. J.; Gerke, H. H.; Hinz, C.

    2015-12-01

    Structural heterogeneity, namely the spatial distribution of soils and sediments (represented by mineral particles), characterizes catchment hydrological behavior. In natural catchments, local geology and the specific geomorphic processes determine the characteristics and spatial distribution of structures. In constructed catchments, structural features are determined primarily by the construction processes and the geological origin of the parent material. Objectives are scenarios of 3D catchment structures in form of complete 3D description of soil hydraulic properties generated from the knowledge of the formation processes. The constructed hydrological catchment 'Hühnerwasser' (Lower Lusatia, Brandenburg, Germany) was used for the calibration and validation of model results due to its well-known conditions. For the modeling of structural features, a structure generator was used to model i) quasi-deterministic sediment distributions using input data from a geological model of the parent material excavation site; ii) sediment distributions that are conditioned to measurement data from soil sampling; and iii) stochastic component sediment distributions. All three approaches allow a randomization within definable limits. Furthermore, the spoil cone / spoil ridge orientation, internal layering, surface compaction and internal spoil cone compaction were modified. These generated structural models were incorporated in a gridded 3D volume model constructed with the GOCAD software. The impact of structure variation was assessed by hydrological modeling with HYDRUS 2D/3D software. 3D distributions of soil hydraulic properties were estimated based on generated sediment properties using adapted pedotransfer functions. Results were compared with hydrological monitoring data. The impact of structural feature variation on hydrological behavior was analyzed by comparing different simulation scenarios. The established initial sediment distributions provide a basis for the

  4. Influence of aquifer heterogeneity on karst hydraulics and catchment delineation employing distributive modeling approaches

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    S. Oehlmann

    2013-07-01

    Full Text Available Due to their heterogeneous nature, karst aquifers pose a major challenge for hydrogeological investigations. Important procedures like the delineation of catchment areas for springs are hindered by the unknown locations and hydraulic properties of highly conductive karstic zones. In this work numerical modeling was employed as a tool in delineating catchment areas of several springs within a karst area in southwestern Germany. For this purpose, different distributive modeling approaches were implemented in the Finite Element simulation software Comsol Multiphysics®. The investigation focuses on the question to which degree the effect of karstification has to be taken into account for accurately simulating the hydraulic head distribution and the observed spring discharges. The results reveal that the representation of heterogeneities has a large influence on the delineation of the catchment areas. Not only the location of highly conductive elements but also their geometries play a major role for the resulting hydraulic head distribution and thus for catchment area delineation. The size distribution of the karst conduits derived from the numerical models agrees with knowledge from karst genesis. It was thus shown that numerical modeling is a useful tool for catchment delineation in karst aquifers based on results from different field observations.

  5. Applying different spatial distribution and modelling concepts in three nested mesoscale catchments of Germany

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    Bongartz, K.

    Distributed, physically based river basin models are receiving increasing importance in integrated water resources management (IWRM) in Germany and in Europe, especially after the release of the new European Water Framework Directive (WFD). Applications in mesoscale catchments require an appropriate approach to represent the spatial distribution of related catchment properties such as land use, soil physics and topography by utilizing techniques of remote sensing and GIS analyses. The challenge is to delineate scale independent homogeneous modelling entities which, on the one hand may represent the dynamics of the dominant hydrological processes and, on the other hand can be derived from spatially distributed physiographical catchment properties. This scaling problem is tackled in this regional modelling study by applying the concept of hydrological response units (HRUs). In a nested catchment approach three different modelling conceptualisations are used to describe the runoff processes: (i) the topographic stream-segment-based HRU delineation proposed by Leavesley et al. [Precipitation-Runoff-Modelling-System, User’s Manual, Water Resource Investigations Report 83-4238, US Geological Survey, 1983]; (ii) the process based physiographic HRU-concept introduced by Flügel [Hydrol. Process. 9 (1995) 423] and (iii) an advanced HRU-concept adapted from (ii), which included the topographic topology of HRU-areas and the river network developed by Staudenraush [Eco Regio 8 (2000) 121]. The influence of different boundary conditions associated with changing the landuse classes, the temporal data resolution and the landuse scenarios were investigated. The mesoscale catchment of the river Ilm ( A∼895 km 2) in Thuringia, Germany, and the Precipitation-Runoff-Modelling-System (PRMS) were selected for this study. Simulations show that the physiographic based concept is a reliable method for modelling basin dynamics in catchments up to 200 km 2 whereas in larger catchments

  6. Extending a rainfall-runoff model for lowland catchments from lumped to semi-distributed

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    Brauer, Claudia; Torfs, Paul; Teuling, Ryan; Uijlenhoet, Remko

    2016-04-01

    The Wageningen Lowland Runoff Simulator (WALRUS) is a parametric rainfall-runoff model for catchments with shallow groundwater (Brauer et al., 2014ab). WALRUS was developed using data and experience from two Dutch experimental catchments: the Hupsel Brook catchment (6.5 km2) and the Cabauw polder (0.5 km2). We identified key processes for runoff generation in lowland catchments, notably (1) groundwater-unsaturated zone coupling, (2) wetness-dependent flow routes, (3) groundwater-surface water feedbacks and (4) seepage and surface water supply, and accounted for these in the model structure. Up to now, WALRUS has been used in a lumped manner. However, water managers and researchers have expressed an interest in a semi-distributed version for application to larger catchments with varying forcing and catchment characteristics and to investigate the effect of groundwater flow within the catchment on modelled variables (e.g. groundwater depth). We combined WALRUS and a model for 2-dimensional groundwater flow into a simple modelling framework. WALRUS was already designed to cope with groundwater flow into or out of the model domain, because seepage and lateral groundwater flow are common in lowlands. In the semi-distributed version, we used this feature to couple different WALRUS elements (grid cells or subcatchments) to each other. Groundwater flow was computed using a digital elevation model, groundwater depths computed by WALRUS, soil transmissivity data and Darcy's law. Finally, we implemented a surface routing model including backwater effects, which are relevant in areas with little relief. With respect to the lumped version, the semi-distributed requires more data. Therefore, we investigated the added value of different data sources (forcing, elevation, soil, surface water) separately. We will present the rationale behind the semi-distributed model and show how the model structure compares to observations and and simulations without lateral transport. C.C. Brauer

  7. Benefits of incorporating spatial organisation of catchments for a semi-distributed hydrological model

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    Schumann, Andreas; Oppel, Henning

    2017-04-01

    To represent the hydrological behaviour of catchments a model should reproduce/reflect the hydrologically most relevant catchment characteristics. These are heterogeneously distributed within a watershed but often interrelated and subject of a certain spatial organisation. Since common models are mostly based on fundamental assumptions about hydrological processes, the reduction of variance of catchment properties as well as the incorporation of the spatial organisation of the catchment is desirable. We have developed a method that combines the idea of the width-function used for determination of the geomorphologic unit hydrograph with information about soil or topography. With this method we are able to assess the spatial organisation of selected catchment characteristics. An algorithm was developed that structures a watershed into sub-basins and other spatial units to minimise its heterogeneity. The outcomes of this algorithm are used for the spatial setup of a semi-distributed model. Since the spatial organisation of a catchment is not bound to a single characteristic, we have to embed information of multiple catchment properties. For this purpose we applied a fuzzy-based method to combine the spatial setup for multiple single characteristics into a union, optimal spatial differentiation. Utilizing this method, we are able to propose a spatial structure for a semi-distributed hydrological model, comprising the definition of sub-basins and a zonal classification within each sub-basin. Besides the improved spatial structuring, the performed analysis ameliorates modelling in another way. The spatial variability of catchment characteristics, which is considered by a minimum of heterogeneity in the zones, can be considered in a parameter constrained calibration scheme in a case study both options were used to explore the benefits of incorporating the spatial organisation and derived parameter constraints for the parametrisation of a HBV-96 model. We use two benchmark

  8. A method to employ the spatial organization of catchments into semi-distributed rainfall-runoff models

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    Oppel, Henning; Schumann, Andreas

    2017-08-01

    A distributed or semi-distributed deterministic hydrological model should consider the hydrologically most relevant catchment characteristics. These are heterogeneously distributed within a watershed but often interrelated and subject to a certain spatial organization which results in archetypes of combined characteristics. In order to reproduce the natural rainfall-runoff response the reduction of variance of catchment properties as well as the incorporation of the spatial organization of the catchment are desirable. In this study the width-function approach is utilized as a basic characteristic to analyse the succession of catchment characteristics. By applying this technique we were able to assess the context of catchment properties like soil or topology along the streamflow length and the network geomorphology, giving indications of the spatial organization of a catchment. Moreover, this information and this technique have been implemented in an algorithm for automated sub-basin ascertainment, which included the definition of zones within the newly defined sub-basins. The objective was to provide sub-basins that were less heterogeneous than common separation schemes. The algorithm was applied to two parameters characterizing the topology and soil of four mid-European watersheds. Resulting partitions indicated a wide range of applicability for the method and the algorithm. Additionally, the intersection of derived zones for different catchment characteristics could give insights into sub-basin similarities. Finally, a HBV96 case study demonstrated the potential benefits of modelling with the new subdivision technique.

  9. Simulating pesticide transport in urbanized catchments: a new spatially-distributed dynamic pesticide runoff model

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    Tang, Ting; Seuntjens, Piet; van Griensven, Ann; Bronders, Jan

    2016-04-01

    depression storage (including degradation, infiltration and runoff). Processes on hard surfaces employs the conceptualization described in the paragraph above. The WetSpa-PST model can account for various spatial details of the urban features in a catchment, such as asphalt, concrete and roof areas. The distributed feature also allows users to input detailed pesticide application data of both non-point and point origins. Thanks to the Python modelling framework prototype used in the WetSpa-Python model, processes in the WetSpa-PST model can be simulated at different time steps depending on data availability and the characteristic temporal scale of each process. This helps to increase the computational accuracy during heavy rainfall events, especially for the associated fast transport of pesticides into surface water. Overall, the WetSpa-PST model has good potential in predicting effects of management options on pesticide releases from heavily urbanized catchments.

  10. Use of spatially distributed time-integrated sediment sampling networks and distributed fine sediment modelling to inform catchment management.

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    Perks, M T; Warburton, J; Bracken, L J; Reaney, S M; Emery, S B; Hirst, S

    2017-11-01

    Under the EU Water Framework Directive, suspended sediment is omitted from environmental quality standards and compliance targets. This omission is partly explained by difficulties in assessing the complex dose-response of ecological communities. But equally, it is hindered by a lack of spatially distributed estimates of suspended sediment variability across catchments. In this paper, we demonstrate the inability of traditional, discrete sampling campaigns for assessing exposure to fine sediment. Sampling frequencies based on Environmental Quality Standard protocols, whilst reflecting typical manual sampling constraints, are unable to determine the magnitude of sediment exposure with an acceptable level of precision. Deviations from actual concentrations range between -35 and +20% based on the interquartile range of simulations. As an alternative, we assess the value of low-cost, suspended sediment sampling networks for quantifying suspended sediment transfer (SST). In this study of the 362 km(2) upland Esk catchment we observe that spatial patterns of sediment flux are consistent over the two year monitoring period across a network of 17 monitoring sites. This enables the key contributing sub-catchments of Butter Beck (SST: 1141 t km(2) yr(-1)) and Glaisdale Beck (SST: 841 t km(2) yr(-1)) to be identified. The time-integrated samplers offer a feasible alternative to traditional infrequent and discrete sampling approaches for assessing spatio-temporal changes in contamination. In conjunction with a spatially distributed diffuse pollution model (SCIMAP), time-integrated sediment sampling is an effective means of identifying critical sediment source areas in the catchment, which can better inform sediment management strategies for pollution prevention and control. Copyright © 2017 Elsevier Ltd. All rights reserved.

  11. Uncertainty in flood forecasting: A distributed modeling approach in a sparse data catchment

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    Mendoza, Pablo A.; McPhee, James; Vargas, Ximena

    2012-09-01

    Data scarcity has traditionally precluded the application of advanced hydrologic techniques in developing countries. In this paper, we evaluate the performance of a flood forecasting scheme in a sparsely monitored catchment based on distributed hydrologic modeling, discharge assimilation, and numerical weather predictions with explicit validation uncertainty analysis. For the hydrologic component of our framework, we apply TopNet to the Cautin River basin, located in southern Chile, using a fully distributed a priori parameterization based on both literature-suggested values and data gathered during field campaigns. Results obtained from this step indicate that the incremental effort spent in measuring directly a set of model parameters was insufficient to represent adequately the most relevant hydrologic processes related to spatiotemporal runoff patterns. Subsequent uncertainty validation performed over a six month ensemble simulation shows that streamflow uncertainty is better represented during flood events, due to both the increase of state perturbation introduced by rainfall and the flood-oriented calibration strategy adopted here. Results from different assimilation configurations suggest that the upper part of the basin is the major source of uncertainty in hydrologic process representation and hint at the usefulness of interpreting assimilation results in terms of model input and parameterization inadequacy. Furthermore, in this case study the violation of Markovian state properties by the Ensemble Kalman filter did affect the numerical results, showing that an explicit treatment of the time delay between the generation of surface runoff and the arrival at the basin outlet is required in the assimilation scheme. Peak flow forecasting results demonstrate that there is a major problem with the Weather Research and Forecasting model outputs, which systematically overestimate precipitation over the catchment. A final analysis performed for a large flooding

  12. Characterizing and reducing equifinality by constraining a distributed catchment model with regional signatures, local observations, and process understanding

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    Kelleher, Christa; McGlynn, Brian; Wagener, Thorsten

    2017-07-01

    Distributed catchment models are widely used tools for predicting hydrologic behavior. While distributed models require many parameters to describe a system, they are expected to simulate behavior that is more consistent with observed processes. However, obtaining a single set of acceptable parameters can be problematic, as parameter equifinality often results in several behavioral sets that fit observations (typically streamflow). In this study, we investigate the extent to which equifinality impacts a typical distributed modeling application. We outline a hierarchical approach to reduce the number of behavioral sets based on regional, observation-driven, and expert-knowledge-based constraints. For our application, we explore how each of these constraint classes reduced the number of behavioral parameter sets and altered distributions of spatiotemporal simulations, simulating a well-studied headwater catchment, Stringer Creek, Montana, using the distributed hydrology-soil-vegetation model (DHSVM). As a demonstrative exercise, we investigated model performance across 10 000 parameter sets. Constraints on regional signatures, the hydrograph, and two internal measurements of snow water equivalent time series reduced the number of behavioral parameter sets but still left a small number with similar goodness of fit. This subset was ultimately further reduced by incorporating pattern expectations of groundwater table depth across the catchment. Our results suggest that utilizing a hierarchical approach based on regional datasets, observations, and expert knowledge to identify behavioral parameter sets can reduce equifinality and bolster more careful application and simulation of spatiotemporal processes via distributed modeling at the catchment scale.

  13. Spatially distributed modeling of sediment and associated heavy metal transport on regional and catchment scale

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    Schindewolf, Marcus; Schmidt, Jürgen; Käpermann, Philipp

    2013-04-01

    Achievements of new legislations, as EU-Water Framework Directive (EU-WFD), require great efforts in order to reduce the yields of sediment and sediment attached heavy metals of surface water bodies. In this regard planning authorities strongly need comparable assessments on regional scale, which enables predictions on the level of measures. The study aims to identify the main sediment delivery areas in the German federal state of Saxony (18400 km²) and to locate pass over points of sediment and associated heavy metals into surface waters. Applying the process based EROSION 3D simulation model spatially distributed (20 m grid cell) estimates of sediment and particle attached heavy metal inputs are realized on regional and catchment scale related to three land use scenarios and a 10years rainfall event. Concerning these calculations it has to be considered, that this substances are predominantly attached to the fine-grained soil particles. The selective nature of soil erosion causes a preferentially transport of this fine particles while less contaminated larger particles remain on site. Consequently heavy metals are enriched in the eroded sediment compared to the origin soil. Hence it is essential that EROSION 3D provides the particle size distribution (clay, silt and sand) of transported sediments. Regarding heavy metal input calculations from sediment inputs, heavy metal contents of particle size classes has to be known. For this purpose particle size separates of erosion susceptible soils are analyzed. Comprehensive heavy metal contents of origin top soils are interpolated via kriging using available monitoring data. The regional scaled simulations identify the Saxon loess belt as the main affected region of sediment inputs. Since particle attached heavy metal transport to surface waters is strongly related to sediment delivery, the streams of this region suffer from considerable inputs. Compared to empirical estimates, the results of this study suggest that

  14. Which spatial discretization for distributed hydrological models? Proposition of a methodology and illustration for medium to large-scale catchments

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    J. Dehotin

    2008-05-01

    Full Text Available Distributed hydrological models are valuable tools to derive distributed estimation of water balance components or to study the impact of land-use or climate change on water resources and water quality. In these models, the choice of an appropriate spatial discretization is a crucial issue. It is obviously linked to the available data, their spatial resolution and the dominant hydrological processes. For a given catchment and a given data set, the "optimal" spatial discretization should be adapted to the modelling objectives, as the latter determine the dominant hydrological processes considered in the modelling. For small catchments, landscape heterogeneity can be represented explicitly, whereas for large catchments such fine representation is not feasible and simplification is needed. The question is thus: is it possible to design a flexible methodology to represent landscape heterogeneity efficiently, according to the problem to be solved? This methodology should allow a controlled and objective trade-off between available data, the scale of the dominant water cycle components and the modelling objectives.

    In this paper, we propose a general methodology for such catchment discretization. It is based on the use of nested discretizations. The first level of discretization is composed of the sub-catchments, organised by the river network topology. The sub-catchment variability can be described using a second level of discretizations, which is called hydro-landscape units. This level of discretization is only performed if it is consistent with the modelling objectives, the active hydrological processes and data availability. The hydro-landscapes take into account different geophysical factors such as topography, land-use, pedology, but also suitable hydrological discontinuities such as ditches, hedges, dams, etc. For numerical reasons these hydro-landscapes can be further subdivided into smaller elements that will constitute the

  15. Development of a data-driven semi-distributed hydrological model for regional scale catchments prone to Mediterranean flash floods

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    Adamovic, M.; Branger, F.; Braud, I.; Kralisch, S.

    2016-10-01

    Flash floods represent one of the most destructive natural hazards in the Mediterranean region. These floods result from very intense and spatially heterogeneous rainfall events. Distributed hydrological models are valuable tools to study these phenomena and increase our knowledge on the main processes governing the generation and propagation of floods over large spatial scales. They are generally built using a bottom-up approach that generalizes small-physics representations of processes. However, top-down or data-driven approach is increasingly shown to provide also valuable knowledge. A simplified semi-distributed continuous hydrological model, named SIMPLEFLOOD, was developed, based on the simple dynamical system approach (SDSA) proposed by Kirchner (WRR, 2009, 45, W02429), and applied to the Ardèche catchment in France (2388 km2). This data-driven method assumes that discharge at the outlet of a given catchment can be expressed as a function only of catchment storage. It leads to a 3-parameter nonlinear model according to rainfall and runoff observations. This model was distributed over sub-catchments and coupled with a kinematic wave based flow propagation module. The parameters were estimated by discharge recession analyses at several gauged stations. Parameter regionalization was conducted using a Factorial Analysis of Mixed Data (FAMD) and Hierarchical Classification on Principal Component (HCPC) in order to find relationships between the SDSA approach and catchments characteristics. Geology was found to be the main predictor of hydrological response variability and model parameters were regionalized according to the dominant geology. The SIMPLEFLOOD model was applied for a 12-year continuous simulation over the Ardèche catchment. Four flash flood events were also selected for further analysis. The simulated hydrographs were compared with the observations at 11 gauging stations with catchment size ranging from 17 to 2300 km2. The results show a good

  16. Integration of Spatially Hydrological Modelling on Bentong Catchment, Pahang, Peninsular Malaysia Using Distributed GIS-based Rainfall Runoff Model

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    Rosli, M.H.

    2017-07-01

    Full Text Available With the advance of GIS technology, hydrology model can simulated at catchment wide scale. The objective is to integrate National Resource Conservation Service (NRCS Curve Number (CN with kinematic wave and manning’s equation using GIS to develop a simple GIS-based distributed model to simulate rainfall runoff in Bentong catchment. Model was built using Spatial Distributed Direct Hydrograph (SDDH concept and applying the time area (TA approach in presenting the predicted discharge hydrograph. The effective precipitation estimation was first calculated using the NRCS CN method. Then, the core maps that consists of digital elevation model (DEM, soil and land use map in grid. DEM was used to derive slope, flow direction and flow accumulation while soil and land use map used to derive roughness coefficient and CN. The overland velocity and channel velocity estimation derived from combination of kinematic wave theory with Manning’s equation. To capture the time frame, the travel time map was divided into isochrones in order to generate the TA histogram and finally. The creation of SDDH using the TA histogram which will lead to the estimation of travel time for the catchment. Simulated hydrograph was plotted together with the observed discharge for comparison. Six storm events used for model performance evaluation using statistical measure such as Nash-Sutcliffe efficiency (NSE, percent bias (PBIAS and coefficient of determination (R2;. SDDH model performed quite well as NSE gave result ranging from 0.55 to 0.68 with mean of 0.6. PBIAS indicate that the model slightly over predicted compared to observed hydrograph with result ranges from -46.71 (the most over predicted to +4.83 (the most under predicted with average of -20.73%. R2; ranges between 0.55 to 0.82 with mean of 0.67. When comparing the time to peak, (tp, min, and peak discharge, (pd, m3/s, results gave NSEtp 0.82, PBIAStp 0.65, R2tp 0.32, NSEpd 0.95, PBIASpd 14.49 and R2pd 0

  17. Flood forecasting using a fully distributed model: application of the TOPKAPI model to the Upper Xixian Catchment

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    Z. Liu

    2005-01-01

    Full Text Available TOPKAPI is a physically-based, fully distributed hydrological model with a simple and parsimonious parameterisation. The original TOPKAPI is structured around five modules that represent evapotranspiration, snowmelt, soil water, surface water and channel water, respectively. Percolation to deep soil layers was ignored in the old version of the TOPKAPI model since it was not important in the basins to which the model was originally applied. Based on published literature, this study developed a new version of the TOPKAPI model, in which the new modules of interception, infiltration, percolation, groundwater flow and lake/reservoir routing are included. This paper presents an application study that makes a first attempt to derive information from public domains through the internet on the topography, soil and land use types for a case study Chinese catchment - the Upper Xixian catchment in Huaihe River with an area of about 10000 km2, and apply a new version of TOPKAPI to the catchment for flood simulation. A model parameter value adjustment was performed using six months of the 1998 dataset. Calibration did not use a curve fitting process, but was chiefly based upon moderate variations of parameter values from those estimated on physical grounds, as is common in traditional calibration. The hydrometeorological dataset of 2002 was then used to validate the model, both against the outlet discharge as well as at an internal gauging station. Finally, to complete the model performance analysis, parameter uncertainty and its effects on predictive uncertainty were also assessed by estimating a posterior parameter probability density via Bayesian inference.

  18. How important is heterogeneous parameter distribution in capturing the catchment response through hydrologic modelling?

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    Devak, Manjula; Dhanya, Ct

    2017-04-01

    The scrupulous selection of critical spatial and temporal resolution and the evaluation of optimum values for various model parameters are essential aspects in any hydrological modelling study. The accurate assessment of various model parameters is vitally important for the detailed and complete representation of the various physical processes illustrating land-atmosphere interaction. Studies in the past have taken up various auto-calibration and parameter transferability schemes to address these; but the heterogeneity of calibration parameters across grids is greatly ignored often. In many studies, heterogeneity is often compromised through the usual interpolation approaches adopted across grids. In the present study, we focus to analyze the response of a catchment by adopting a heterogeneous and homogeneous parameter distribution in the hydrological model. The semi-distributed hydrological model, Variable Infiltration Capacity (VIC-3L) model, which offers sub-grid variability in soil moisture storage capacity and vegetation classes, is used for this comparison. Nine model parameters are selected for calibrating the VIC-3L model, namely variable infiltration curve parameter (infilt), maximum velocity of base flow for each grid cells (DSmax), fraction of DSmax where non-linear base flow begins (DS, fraction of maximum soil moisture where non-linear base flow occurs (WS), depth of 2nd soil layer (D2), depth of 3rd soil layer (D3), exponent used in baseflow curve (c), advection coefficient (C) and diffusion coefficient (D). Latin-Hypercube sampling is adopted to sample these nine parameters. In homogenous approach, the traditional way of constant soil parameter distribution (HoSCP) is adopted to prepare the parameter set. While, in heterogeneous approach, grid-to-grid variability is ensured by constructing a Heterogeneous Soil Calibration Parameter (HeSCP) set through systematic sampling of already sampled set. The sampling size is made equal to the number of grids

  19. Modeling radiocesium transport from a river catchment based on a physically-based distributed hydrological and sediment erosion model.

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    Kinouchi, Tsuyoshi; Yoshimura, Kazuya; Omata, Teppei

    2015-01-01

    The accident at the Fukushima Dai-ichi Nuclear Power Plant (FDNPP) in March 2011 resulted in the deposition of large quantities of radionuclides, such as (134)Cs and (137)Cs, over parts of eastern Japan. Since then high levels of radioactive contamination have been detected in large areas, including forests, agricultural land, and residential areas. Due to the strong adsorption capability of radiocesium to soil particles, radiocesium migrates with eroded sediments, follows the surface flow paths, and is delivered to more populated downstream regions and eventually to the Pacific Ocean. It is therefore important to understand the transport of contaminated sediments in the hydrological system and to predict changes in the spatial distribution of radiocesium concentrations by taking the land-surface processes related to sediment migration into consideration. In this study, we developed a distributed model to simulate the transport of water and contaminated sediment in a watershed hydrological system, and applied this model to a partially forested mountain catchment located in an area highly contaminated by the radioactive fallout. Observed discharge, sediment concentration, and cesium concentration measured from June 2011 until December 2012 were used for calibration of model parameters. The simulated discharge and sediment concentration both agreed well with observed values, while the cesium concentration was underestimated in the initial period following the accident. This result suggests that the leaching of radiocesium from the forest canopy, which was not considered in the model, played a significant role in its transport from the catchment. Based on the simulation results, we quantified the long-term fate of radiocesium over the study area and estimated that the effective half-life of (137)Cs deposited in the study area will be approximately 22 y due to the export of contaminated sediment by land-surface processes, and the amount of (137)Cs remaining in the

  20. Water balance complexities in ephemeral catchments with different land uses: Insights from monitoring and distributed hydrologic modeling

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    Dean, J. F.; Camporese, M.; Webb, J. A.; Grover, S. P.; Dresel, P. E.; Daly, E.

    2016-06-01

    Although ephemeral catchments are widespread in arid and semiarid climates, the relationship of their water balance with climate, geology, topography, and land cover is poorly known. Here we use 4 years (2011-2014) of rainfall, streamflow, and groundwater level measurements to estimate the water balance components in two adjacent ephemeral catchments in south-eastern Australia, with one catchment planted with young eucalypts and the other dedicated to grazing pasture. To corroborate the interpretation of the observations, the physically based hydrological model CATHY was calibrated and validated against the data in the two catchments. The estimated water balances showed that despite a significant decline in groundwater level and greater evapotranspiration in the eucalypt catchment (104-119% of rainfall) compared with the pasture catchment (95-104% of rainfall), streamflow consistently accounted for 1-4% of rainfall in both catchments for the entire study period. Streamflow in the two catchments was mostly driven by the rainfall regime, particularly rainfall frequency (i.e., the number of rain days per year), while the downslope orientation of the plantation furrows also promoted runoff. With minimum calibration, the model was able to adequately reproduce the periods of flow in both catchments in all years. Although streamflow and groundwater levels were better reproduced in the pasture than in the plantation, model-computed water balance terms confirmed the estimates from the observations in both catchments. Overall, the interplay of climate, topography, and geology seems to overshadow the effect of land use in the study catchments, indicating that the management of ephemeral catchments remains highly challenging.

  1. Water Use and Management in Semiarid Regions - A Distributed Modelling Approach in the Verlorenvlei Catchment, South Africa

    Science.gov (United States)

    Fleischer, Melanie; Kralisch, Sven; Fink, Manfred; Pfennig, Björn; Butchart-Kuhlmann, Daniel; Meinhardt, Markus; de Clercq, Willem

    2016-04-01

    Hydrological modelling is a useful method to predict water availability and environmental impacts in a range of climate and land use change scenarios. One of the major challenges to accurate predictions using hydrological modelling in semi-arid areas is the high temporal and spatial variability of rainfall events and the associated uncertainty of related process parameters. Limited and often unreliable climate observations can cause additional problems. These particular circumstances are well documented for many catchments in the world, including semi-arid parts of South Africa. An accurate assessment of water quality and quantity is however crucial for sustainable water resource management, which is often difficult under changing environmental conditions such as climate and land use change. This situation can be found in the Verlorenvlei catchment, a part of the Sandveld area located in the Western Cape region of South Africa. Extensive dry periods in combination with an increasing domestic water demand, expanding irrigation agriculture and expected reducing rainfall due to climate change present a challenging setup for water management in this region. The catchment is a highly sensitive area with one of the most important estuary systems in the Western Cape region, containing significant natural wetlands with high biodiversity and numerous endemic species. With very limited surface water resources, most settlements and irrigation systems in the region are mainly dependent on groundwater. As a result of the particular conditions, the use of improved management techniques, such as centre pivot irrigation and contour-bank farming, are necessary. The distributed, process-oriented hydrological modelling system JAMS/J2000 is used and evaluated to assess water availability within the catchment under different climate and land-use change scenarios. The first phase has involved configuring the model to accurately represent the specific natural conditions of the

  2. Sediment transport modelling in a distributed physically based hydrological catchment model

    Directory of Open Access Journals (Sweden)

    M. Konz

    2011-09-01

    Full Text Available Bedload sediment transport and erosion processes in channels are important components of water induced natural hazards in alpine environments. A raster based distributed hydrological model, TOPKAPI, has been further developed to support continuous simulations of river bed erosion and deposition processes. The hydrological model simulates all relevant components of the water cycle and non-linear reservoir methods are applied for water fluxes in the soil, on the ground surface and in the channel. The sediment transport simulations are performed on a sub-grid level, which allows for a better discretization of the channel geometry, whereas water fluxes are calculated on the grid level in order to be CPU efficient. Several transport equations as well as the effects of an armour layer on the transport threshold discharge are considered. Flow resistance due to macro roughness is also considered. The advantage of this approach is the integrated simulation of the entire basin runoff response combined with hillslope-channel coupled erosion and transport simulation. The comparison with the modelling tool SETRAC demonstrates the reliability of the modelling concept. The devised technique is very fast and of comparable accuracy to the more specialised sediment transport model SETRAC.

  3. Rainfall-Runoff Simulations in Arid Catchments in Sinai Peninsula, Egypt, using a Distributed Physically-based Hydrologic Model

    Science.gov (United States)

    Habib, E.; Elsayed, E. A.; Abdel-Motaleb, M.

    2008-05-01

    Egypt's Sinai Peninsula falls within an arid climatic belt that crosses northern Africa and southwestern Asia. Despite its aridity, Sinai is occasionally subjected to heavy rainfall causing flash floods, which are commonly characterized by sharp peak discharges with short durations. Several flash floods were recorded in south Sinai, which resulted in significant infrastructural damages, population displacement and, sometimes, loss of lives. Despite their hazardous effects, flash floods in Sinai, and other parts of southern Egypt, represent a potential resource for non-conventional fresh water sources. In order to mitigate flash flood damages and efficiently harvest the flash-flood highly needed fresh water, it is crucially important to accurately predict the occurrence of flash floods in terms of both timing and magnitude. Several studies have been implemented to develop hydrologic models for predicting flash floods in Sinai. In these studies, methodologies that are primarily conceptual, such as synthetic unit hydrographs, have shown little success at reproducing observed flood hydrographs. Physically-based distributed models provide an alternative approach for modeling food events in the Sinai arid environment. This study will examine the utility of a physically-based distributed hydrologic model (Gridded Surface-Subsurface Hydrologic Analysis, GSSHA) to simulate rainfall-runoff response in a small and a mid-size catchment in Sinai. GSSHA is a fully distributed-parameter, process-based hydrologic model that uses finite difference and finite volume methods to simulate different hydrologic processes. The watershed topographic and hydrologic properties are represented using Cartesian grids in the order of 100x100 m2. Overland hydraulic properties and soil hydraulic parameters were varied according to combined spatial classifications of soil type and land use maps. Field measurements of soil types and infiltration parameters were used to initially assign model

  4. Probabilistic flood forecasting for Rapid Response Catchments using a countrywide distributed hydrological model: experience from the UK

    Science.gov (United States)

    Cole, Steven J.; Moore, Robert J.; Robson, Alice J.; Mattingley, Paul S.

    2014-05-01

    Across Britain, floods in rapidly responding catchments are a major concern and regularly cause significant damage (e.g. Boscastle 2004, Morpeth 2008, Cornwall 2010 and Comrie 2012). Typically these catchments have a small area and are characterised by steep slopes and/or significant suburban/urban land-cover. The meteorological drivers can be of convective origin or frontal with locally intense features (e.g. embedded convection or orographic enhancement); saturated catchments can amplify the flood response. Both rainfall and flood forecasting for Rapid Response Catchments (RRCs)are very challenging due to the often small-scale nature of the intense rainfall which is of most concern, the small catchment areas, and the short catchment response times. Over the last 3 to 4 years, new countrywide Flood Forecasting Systems based on the Grid-to-Grid (G2G) distributed hydrological (rainfall-runoff and routing) model have been implemented across Britain for use by the Flood Forecasting Centre and Scottish Flood Forecasting Service. This has achieved a step-change in operational capability with forecasts of flooding several days ahead "everywhere" on a 1 km grid now possible. The modelling and forecasting approach underpins countrywide Flood Guidance Statements out to 5 days which are used by emergency response organisations for planning and preparedness. The initial focus of these systems has been to provide a countrywide overview of flood risk. However, recent research has explored the potential of the G2G approach to support more frequent and detailed alerts relevant to flood warning in RRCs. Integral to this activity is the use of emerging high-resolution (~1.5km) rainfall forecast products, in deterministic and ensemble form. High spatial resolutions are required to capture some of the small-scale processes and intense rainfall features such as orographic enhancement and convective storm evolution. Even though a deterministic high-resolution numerical weather

  5. Modelling the spatial distribution of snow water equivalent at the catchment scale taking into account changes in snow covered area

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    T. Skaugen

    2011-12-01

    Full Text Available A successful modelling of the snow reservoir is necessary for water resources assessments and the mitigation of spring flood hazards. A good estimate of the spatial probability density function (PDF of snow water equivalent (SWE is important for obtaining estimates of the snow reservoir, but also for modelling the changes in snow covered area (SCA, which is crucial for the runoff dynamics in spring. In a previous paper the PDF of SWE was modelled as a sum of temporally correlated gamma distributed variables. This methodology was constrained to estimate the PDF of SWE for snow covered areas only. In order to model the PDF of SWE for a catchment, we need to take into account the change in snow coverage and provide the spatial moments of SWE for both snow covered areas and for the catchment as a whole. The spatial PDF of accumulated SWE is, also in this study, modelled as a sum of correlated gamma distributed variables. After accumulation and melting events the changes in the spatial moments are weighted by changes in SCA. The spatial variance of accumulated SWE is, after both accumulation- and melting events, evaluated by use of the covariance matrix. For accumulation events there are only positive elements in the covariance matrix, whereas for melting events, there are both positive and negative elements. The negative elements dictate that the correlation between melt and SWE is negative. The negative contributions become dominant only after some time into the melting season so at the onset of the melting season, the spatial variance thus continues to increase, for later to decrease. This behaviour is consistent with observations and called the "hysteretic" effect by some authors. The parameters for the snow distribution model can be estimated from observed historical precipitation data which reduces by one the number of parameters to be calibrated in a hydrological model. Results from the model are in good agreement with observed spatial moments

  6. Modelling the spatial distribution of snow water equivalent at the catchment scale taking into account changes in snow covered area

    Science.gov (United States)

    Skaugen, T.; Randen, F.

    2011-12-01

    A successful modelling of the snow reservoir is necessary for water resources assessments and the mitigation of spring flood hazards. A good estimate of the spatial probability density function (PDF) of snow water equivalent (SWE) is important for obtaining estimates of the snow reservoir, but also for modelling the changes in snow covered area (SCA), which is crucial for the runoff dynamics in spring. In a previous paper the PDF of SWE was modelled as a sum of temporally correlated gamma distributed variables. This methodology was constrained to estimate the PDF of SWE for snow covered areas only. In order to model the PDF of SWE for a catchment, we need to take into account the change in snow coverage and provide the spatial moments of SWE for both snow covered areas and for the catchment as a whole. The spatial PDF of accumulated SWE is, also in this study, modelled as a sum of correlated gamma distributed variables. After accumulation and melting events the changes in the spatial moments are weighted by changes in SCA. The spatial variance of accumulated SWE is, after both accumulation- and melting events, evaluated by use of the covariance matrix. For accumulation events there are only positive elements in the covariance matrix, whereas for melting events, there are both positive and negative elements. The negative elements dictate that the correlation between melt and SWE is negative. The negative contributions become dominant only after some time into the melting season so at the onset of the melting season, the spatial variance thus continues to increase, for later to decrease. This behaviour is consistent with observations and called the "hysteretic" effect by some authors. The parameters for the snow distribution model can be estimated from observed historical precipitation data which reduces by one the number of parameters to be calibrated in a hydrological model. Results from the model are in good agreement with observed spatial moments of SWE and SCA

  7. Integrating satellite actual evapotranspiration patterns into distributed model parametrization and evaluation for a mesoscale catchment

    Science.gov (United States)

    Demirel, M. C.; Mai, J.; Stisen, S.; Mendiguren González, G.; Koch, J.; Samaniego, L. E.

    2016-12-01

    Distributed hydrologic models are traditionally calibrated and evaluated against observations of streamflow. Spatially distributed remote sensing observations offer a great opportunity to enhance spatial model calibration schemes. For that it is important to identify the model parameters that can change spatial patterns before the satellite based hydrologic model calibration. Our study is based on two main pillars: first we use spatial sensitivity analysis to identify the key parameters controlling the spatial distribution of actual evapotranspiration (AET). Second, we investigate the potential benefits of incorporating spatial patterns from MODIS data to calibrate the mesoscale Hydrologic Model (mHM). This distributed model is selected as it allows for a change in the spatial distribution of key soil parameters through the calibration of pedo-transfer function parameters and includes options for using fully distributed daily Leaf Area Index (LAI) directly as input. In addition the simulated AET can be estimated at the spatial resolution suitable for comparison to the spatial patterns observed using MODIS data. We introduce a new dynamic scaling function employing remotely sensed vegetation to downscale coarse reference evapotranspiration. In total, 17 parameters of 47 mHM parameters are identified using both sequential screening and Latin hypercube one-at-a-time sampling methods. The spatial patterns are found to be sensitive to the vegetation parameters whereas streamflow dynamics are sensitive to the PTF parameters. The results of multi-objective model calibration show that calibration of mHM against observed streamflow does not reduce the spatial errors in AET while they improve only the streamflow simulations. We will further examine the results of model calibration using only multi spatial objective functions measuring the association between observed AET and simulated AET maps and another case including spatial and streamflow metrics together.

  8. Three very high resolution optical images for land use mapping of a suburban catchment: input to distributed hydrological models

    Science.gov (United States)

    Jacqueminet, Christine; Kermadi, Saïda; Michel, Kristell; Jankowfsky, Sonja; Braud, Isabelle; Branger, Flora; Beal, David; Gagnage, Matthieu

    2010-05-01

    Keywords : land cover mapping, very high resolution, remote sensing processing techniques, object oriented approach, distributed hydrological model, peri-urban area Urbanization and other modifications of land use affect the hydrological cycle of suburban catchments. In order to quantify these impacts, the AVuPUR project (Assessing the Vulnerability of Peri-Urban Rivers) is currently developing a distributed hydrological model that includes anthropogenic features. The case study is the Yzeron catchment (150 km²), located close to Lyon city, France. This catchment experiences a growing of urbanization and a modification of traditional land use since the middle of the 20th century, resulting in an increase of flooding, water pollution and river banks erosion. This contribution discusses the potentials of automated data processing techniques on three different VHR images, in order to produce appropriate and detailed land cover data for the models. Of particular interest is the identification of impermeable surfaces (buildings, roads, and parking places) and permeable surfaces (forest areas, agricultural fields, gardens, trees…) within the catchment, because their infiltration capacity and their impact on runoff generation are different. Three aerial and spatial images were acquired: (1) BD Ortho IGN aerial images, 0.50 m resolution, visible bands, may 5th 2008; (2) QuickBird satellite image, 2.44 m resolution, visible and near-infrared bands, august 29th 2008; (3) Spot satellite image, 2.50 m resolution, visible and near-infrared bands, September 22nd 2008. From these images, we developed three image processing methods: (1) a pixel-based method associated to a segmentation using Matlab®, (2) a pixel-based method using ENVI®, (3) an object-based classification using Definiens®. We extracted six land cover types from the BD Ortho IGN (visible bands) and height classes from the satellite images (visible and near infrared bands). The three classified images are

  9. Comparative Assessment of Runoff and its Components in Two Catchments of Upper Indus Basin by Using a Semi Distributed Glacio-Hydrological Model

    Science.gov (United States)

    Ali, S. H.; Bano, I.; Kayastha, R. B.; Shrestha, A.

    2017-09-01

    The hydrology of Upper Indus basin is not recognized well due to the intricacies in the climate and geography, and the scarcity of data above 5000 m a.s.l where most of the precipitation falls in the form of snow. The main objective of this study is to measure the contributions of different components of runoff in Upper Indus basin. To achieve this goal, the Modified positive degree day model (MPDDM) was used to simulate the runoff and investigate its components in two catchments of Upper Indus basin, Hunza and Gilgit River basins. These two catchments were selected because of their different glacier coverage, contrasting area distribution at high altitudes and significant impact on the Upper Indus River flow. The components of runoff like snow-ice melt and rainfall-base flow were identified by the model. The simulation results show that the MPDDM shows a good agreement between observed and modeled runoff of these two catchments and the effects of snow and ice are mainly reliant on the catchment characteristics and the glaciated area. For Gilgit River basin, the largest contributor to runoff is rain-base flow, whereas large contribution of snow-ice melt observed in Hunza River basin due to its large fraction of glaciated area. This research will not only contribute to the better understanding of the impacts of climate change on the hydrological response in the Upper Indus, but will also provide guidance for the development of hydropower potential and water resources assessment in these catchments.

  10. Water and nutrient balances in a large tile-drained agricultural catchment: a distributed modeling study

    Directory of Open Access Journals (Sweden)

    H. Li

    2010-11-01

    Full Text Available This paper presents the development and implementation of a distributed model of coupled water nutrient processes, based on the representative elementary watershed (REW approach, to the Upper Sangamon River Basin, a large, tile-drained agricultural basin located in central Illinois, mid-west of USA. Comparison of model predictions with the observed hydrological and biogeochemical data, as well as regional estimates from literature studies, shows that the model is capable of capturing the dynamics of water, sediment and nutrient cycles reasonably well. The model is then used as a tool to gain insights into the physical and chemical processes underlying the inter- and intra-annual variability of water and nutrient balances. Model predictions show that about 80% of annual runoff is contributed by tile drainage, while the remainder comes from surface runoff (mainly saturation excess flow and subsurface runoff. It is also found that, at the annual scale nitrogen storage in the soil is depleted during wet years, and is supplemented during dry years. This carryover of nitrogen storage from dry year to wet year is mainly caused by the lateral loading of nitrate. Phosphorus storage, on the other hand, is not affected much by wet/dry conditions simply because the leaching of it is very minor compared to the other mechanisms taking phosphorous out of the basin, such as crop harvest. The analysis then turned to the movement of nitrate with runoff. Model results suggested that nitrate loading from hillslope into the channel is preferentially carried by tile drainage. Once in the stream it is then subject to in-stream denitrification, the significant spatio-temporal variability of which can be related to the variation of the hydrologic and hydraulic conditions across the river network.

  11. Water and Nutrient Balances in a Large Tile-Drained Agricultural Catchment: A Distributed Modeling Study

    Energy Technology Data Exchange (ETDEWEB)

    Li, Hongyi; Sivapalan, Murugesu; Tian, Fuqiang; Liu, Dengfeng

    2010-11-16

    This paper presents the development and implementation of a distributed model of coupled water nutrient processes, based on the representative elementary watershed (REW) approach, to the Upper Sangamon River Basin, a large, tile-drained agricultural basin located in central Illinois, mid-west of USA. Comparison of model predictions with the observed hydrological and biogeochemical data, as well as regional estimates from literature studies, shows that the model is capable of capturing the dynamics of water, sediment and nutrient cycles reasonably well. The model is then used as a tool to gain insights into the physical and chemical processes underlying the inter- and intra-annual variability of water and nutrient balances. Model predictions show that about 80% of annual runoff is contributed by tile drainage, while the remainder comes from surface runoff (mainly saturation excess flow) and subsurface runoff. It is also found that, at the annual scale nitrogen storage in the soil is depleted during wet years, and is supplemented during dry years. This carryover of nitrogen storage from dry year to wet year is mainly caused by the lateral loading of nitrate. Phosphorus storage, on the other hand, is not affected much by wet/dry conditions simply because the leaching of it is very minor compared to the other mechanisms taking phosphorous out of the basin, such as crop harvest. The analysis then turned to the movement of nitrate with runoff. Model results suggested that nitrate loading from hillslope into the channel is preferentially carried by tile drainage. Once in the stream it is then subject to in-stream denitrification, the significant spatio-temporal variability of which can be related to the variation of the hydrologic and hydraulic conditions across the river network.

  12. Localized bedrock aquifer distribution explains discharge from a headwater catchment

    Science.gov (United States)

    Kosugi, Ken'ichirou; Fujimoto, Masamitsu; Katsura, Shin'ya; Kato, Hiroyuki; Sando, Yoshiki; Mizuyama, Takahisa

    2011-07-01

    Understanding a discharge hydrograph is one of the leading interests in catchment hydrology. Recent research has provided credible information on the importance of bedrock groundwater on discharge hydrographs from headwater catchments. However, intensive monitoring of bedrock groundwater is rare in mountains with steep topography. Hence, how bedrock groundwater controls discharge from a steep headwater catchment is in dispute. In this study, we conducted long-term hydrological observations using densely located bedrock wells in a headwater catchment underlain by granitic bedrock. The catchment has steep topography affected by diastrophic activities. Results showed a fairly regionalized distribution of bedrock aquifers within a scale of tens of meters, consisting of upper, middle, and lower aquifers, instead of a gradual and continuous decline in water level from ridge to valley bottom. This was presumably attributable to the unique bedrock structure; fault lines developed in the watershed worked to form divides between the bedrock aquifers. Spatial expanse of each aquifer and the interaction among aquifers were key factors to explain gentle and considerable variations in the base flow discharge and triple-peak discharge responses of the observed hydrograph. A simple model was developed to simulate the discharge hydrograph, which computed each of the contributions from the soil mantle groundwater, from the lower aquifer, and from the middle aquifer to the discharge. The modeling results generally succeeded in reproducing the observed hydrograph. Thus, this study demonstrated that understanding regionalized bedrock aquifer distribution is pivotal for explaining discharge hydrograph from headwater catchments that have been affected by diastrophic activities.

  13. Use of distributed water level and soil moisture data in the evaluation of the PUMMA periurban distributed hydrological model: application to the Mercier catchment, France

    Science.gov (United States)

    Braud, Isabelle; Fuamba, Musandji; Branger, Flora; Batchabani, Essoyéké; Sanzana, Pedro; Sarrazin, Benoit; Jankowfsky, Sonja

    2016-04-01

    Distributed hydrological models are used at best when their outputs are compared not only to the outlet discharge, but also to internal observed variables, so that they can be used as powerful hypothesis-testing tools. In this paper, the interest of distributed networks of sensors for evaluating a distributed model and the underlying functioning hypotheses is explored. Two types of data are used: surface soil moisture and water level in streams. The model used in the study is the periurban PUMMA (Peri-Urban Model for landscape Management, Jankowfsky et al., 2014), that is applied to the Mercier catchment (6.7 km2) a semi-rural catchment with 14% imperviousness, located close to Lyon, France where distributed water level (13 locations) and surface soil moisture data (9 locations) are available. Model parameters are specified using in situ information or the results of previous studies, without any calibration and the model is run for four years from January 1st 2007 to December 31st 2010 with a variable time step for rainfall and an hourly time step for reference evapotranspiration. The model evaluation protocol was guided by the available data and how they can be interpreted in terms of hydrological processes and constraints for the model components and parameters. We followed a stepwise approach. The first step was a simple model water balance assessment, without comparison to observed data. It can be interpreted as a basic quality check for the model, ensuring that it conserves mass, makes the difference between dry and wet years, and reacts to rainfall events. The second step was an evaluation against observed discharge data at the outlet, using classical performance criteria. It gives a general picture of the model performance and allows to comparing it to other studies found in the literature. In the next steps (steps 3 to 6), focus was made on more specific hydrological processes. In step 3, distributed surface soil moisture data was used to assess the

  14. Simulating spatially distributed catchment response using a fully-integrated surface-subsurface model based on dual calibration with streamflow and evapotranspiration

    Science.gov (United States)

    Ala-aho, Pertti; Soulsby, Chris; Wang, Hailong; Tetzlaff, Doerthe

    2016-04-01

    We use above-ground hydrological fluxes (streamflow and evapotranspiration (ET)) to calibrate an integrated hydrological simulator for a headwater catchment located in the Scottish highlands. Our study explores the feasibility of simulating spatially distributed catchment response in a physically based framework whilst having only preliminary data about the subsurface hydrological parameters. Furthermore we investigate the added value of insitu ET data in the calibration process. Transient simulations are performed with a fully integrated surface-subsurface hydrological model HydroGeoSphere and calibration of model parameters is done in PEST framework. In the first calibration step only the stream hydrograph is included using the original time series alongside with log-transformed hydrograph and weekly flow volumes in the objective function. ET is estimated with energy balance technique using above canopy temperatures, humidity and net radiation measured within the catchment. In the second calibration step, the ET time series are introduced in the calibration objective function. Parameter identifiability along with uncertainty in the model output will be examined as a part of the model calibration for both calibration steps. Furthermore, the post-calibration model will allow us to simulate spatially distributed hydrological fluxes and to distinguish between different water sources that make up the stream hydrograph using the hydraulic mixing-cell method. Preliminary simulations have shown that transient and spatially distributed surface water, subsurface water and evaporative fluxes of a headwater catchment can be reproduced in integrated modelling framework using only above-ground hydrological data in model calibration. We hypothesize that the evapotranspiration dataset informs the catchment water budget and water transmission rates and is therefore useful in constraining subsurface hydraulic parameters, such as hydraulic conductivities, which are typically

  15. COMPARATIVE ASSESSMENT OF RUNOFF AND ITS COMPONENTS IN TWO CATCHMENTS OF UPPER INDUS BASIN BY USING A SEMI DISTRIBUTED GLACIO-HYDROLOGICAL MODEL

    Directory of Open Access Journals (Sweden)

    S. H. Ali

    2017-09-01

    Full Text Available The hydrology of Upper Indus basin is not recognized well due to the intricacies in the climate and geography, and the scarcity of data above 5000 m a.s.l where most of the precipitation falls in the form of snow. The main objective of this study is to measure the contributions of different components of runoff in Upper Indus basin. To achieve this goal, the Modified positive degree day model (MPDDM was used to simulate the runoff and investigate its components in two catchments of Upper Indus basin, Hunza and Gilgit River basins. These two catchments were selected because of their different glacier coverage, contrasting area distribution at high altitudes and significant impact on the Upper Indus River flow. The components of runoff like snow-ice melt and rainfall-base flow were identified by the model. The simulation results show that the MPDDM shows a good agreement between observed and modeled runoff of these two catchments and the effects of snow and ice are mainly reliant on the catchment characteristics and the glaciated area. For Gilgit River basin, the largest contributor to runoff is rain-base flow, whereas large contribution of snow-ice melt observed in Hunza River basin due to its large fraction of glaciated area. This research will not only contribute to the better understanding of the impacts of climate change on the hydrological response in the Upper Indus, but will also provide guidance for the development of hydropower potential and water resources assessment in these catchments.

  16. Analyzing catchment behavior through catchment modeling in the Gilgel Abay, Upper Blue Nile River Basin, Ethiopia

    Directory of Open Access Journals (Sweden)

    S. Uhlenbrook

    2010-10-01

    Full Text Available Understanding catchment hydrological processes is essential for water resources management, in particular in data scarce regions. The Gilgel Abay catchment (a major tributary into Lake Tana, source of the Blue Nile is undergoing intensive plans for water management, which is part of larger development plans in the Blue Nile basin in Ethiopia. To obtain a better understanding of the water balance dynamics and runoff generation mechanisms and to evaluate model transferability, catchment modeling has been conducted using the conceptual hydrological model HBV. Accordingly, the catchment of the Gilgel Abay has been divided into two gauged sub-catchments (Upper Gilgel Abay and Koga and the un-gauged part of the catchment. All available data sets were tested for stationarity, consistency and homogeneity and the data limitations (quality and quantity are discussed. Manual calibration of the daily models for three different catchment representations, i.e. (i lumped, (ii lumped with multiple vegetation zones, and (iii semi-distributed with multiple vegetation and elevation zones, showed good to satisfactory model performances with Nash-Sutcliffe efficiencies Reff > 0.75 and > 0.6 for the Upper Gilgel Abay and Koga sub-catchments, respectively. Better model results could not be obtained with manual calibration, very likely due to the limited data quality and model insufficiencies. Increasing the computation time step to 15 and 30 days improved the model performance in both sub-catchments to Reff > 0.8. Model parameter transferability tests have been conducted by interchanging parameters sets between the two gauged sub-catchments. Results showed poor performances for the daily models (0.30 < Reff < 0.67, but better performances for the 15 and 30 days models, Reff > 0.80. The transferability tests together with a sensitivity analysis using Monte Carlo simulations (more than 1 million

  17. Catchments catch all in South African coastal lowlands: topography and palaeoclimate restricted gene flow in Nymania capensis (Meliaceae)—a multilocus phylogeographic and distribution modelling approach

    Science.gov (United States)

    2017-01-01

    Background This study investigates orbitally-forced range dynamics at a regional scale by exploring the evolutionary history of Nymania capensis (Meliaceae) across the deeply incised landscapes of the subescarpment coastal lowlands of South Africa; a region that is home to three biodiversity hotspots (Succulent Karoo, Fynbos, and Maputaland-Pondoland-Albany hotspots). Methods A range of methods are used including: multilocus phylogeography (chloroplast and high- and low-copy nuclear DNA), molecular dating and species distribution modelling (SDM). Results The results support an ‘evolutionarily distinct catchment’ hypothesis where: (1) different catchments contain genetically distinct lineages, (2) limited genetic structuring was detected within basins whilst high structuring was detected between basins, and (3) within primary catchment populations display a high degree of genealogical lineage sorting. In addition, the results support a glacial refugia hypothesis as: (a) the timing of chloroplast lineage diversification is restricted to the Pleistocene in a landscape that has been relatively unchanged since the late Pliocene, and (b) the projected LGM distribution of suitable climate for N. capensis suggest fragmentation into refugia that correspond to the current phylogeographic populations. Discussion This study highlights the interaction of topography and subtle Pleistocene climate variations as drivers limiting both seed and pollen flow along these lowlands. This lends support to the region’s large-scale conservation planning efforts, which used catchments as foundational units for conservation as these are likely to be evolutionarily significant units.

  18. Inter-comparison of experimental catchment data and hydrological modelling

    Science.gov (United States)

    Singh, Shailesh Kumar; Ibbitt, Richard; Srinivasan, M. S.; Shankar, Ude

    2017-07-01

    Hydrological models account for the storage, flow of water and water balance in a catchment, including exchanges of water and energy with the ground, atmosphere and oceans. Because of the need to simplify hydrological models, parameters are often included to help with modelling hydrological processes. Generally the parameters of lumped, semi or distributed hydrological models depend on the values estimated at a gauged location, generally at outlet of the catchment (mostly using discharge). In this approach it is hard to judge how well a model represents internal catchment processes of the hydrological cycle as well as also ignoring the spatial heterogeneity of the catchment. The purpose of the paper is to assess, and potentially improve, the ability of a physically-based semi-distributed hydrological model, TopNet, using a spatially and temporally detailed set of field measurements of catchment responses to diverse weather conditions. The TopNet rainfall-runoff model was applied to the Waipara catchment located in the South Island of New Zealand. Observations from field experiments were compared with the simulation results of uncalibrated TopNet model. The total amount of simulated runoff showed reasonable agreement with observations. However, the model overestimated baseflow and underestimated surface flow. The results show that soil moisture variation within the catchment is well represented by the model. However, comparison of the observed water balance with model results show that there is a deficiency in the calculation of evapotranspiration.

  19. Analyzing the hydrological impact of afforestation and tree species in two catchments with contrasting soil properties using the spatially distributed model MIKE SHE SWET

    DEFF Research Database (Denmark)

    Sonnenborg, Torben Obel; Christiansen, Jesper Riis; Pang, Bo

    2017-01-01

    Groundwater depletion occurs at a global scale but requires regional strategies for sustainable management of freshwater resources. In Denmark the groundwater quantity and quality is under pressure, and forested areas are considered to protect groundwater reservoirs. However, little is known on how...... afforestation or forest conversion impacts the water resource at the catchment scale. We hypothesize that the groundwater formation and streamflow is increased when water consuming conifers are replaced with the less consumptive broadleaf tree species. To test this a distributed hydrological model...

  20. Incorporating flood event analyses and catchment structures into model development

    Science.gov (United States)

    Oppel, Henning; Schumann, Andreas

    2016-04-01

    The space-time variability in catchment response results from several hydrological processes which differ in their relevance in an event-specific way. An approach to characterise this variance consists in comparisons between flood events in a catchment and between flood responses of several sub-basins in such an event. In analytical frameworks the impact of space and time variability of rainfall on runoff generation due to rainfall excess can be characterised. Moreover the effect of hillslope and channel network routing on runoff timing can be specified. Hence, a modelling approach is needed to specify the runoff generation and formation. Knowing the space-time variability of rainfall and the (spatial averaged) response of a catchment it seems worthwhile to develop new models based on event and catchment analyses. The consideration of spatial order and the distribution of catchment characteristics in their spatial variability and interaction with the space-time variability of rainfall provides additional knowledge about hydrological processes at the basin scale. For this purpose a new procedure to characterise the spatial heterogeneity of catchments characteristics in their succession along the flow distance (differentiated between river network and hillslopes) was developed. It was applied to study of flood responses at a set of nested catchments in a river basin in eastern Germany. In this study the highest observed rainfall-runoff events were analysed, beginning at the catchment outlet and moving upstream. With regard to the spatial heterogeneities of catchment characteristics, sub-basins were separated by new algorithms to attribute runoff-generation, hillslope and river network processes. With this procedure the cumulative runoff response at the outlet can be decomposed and individual runoff features can be assigned to individual aspects of the catchment. Through comparative analysis between the sub-catchments and the assigned effects on runoff dynamics new

  1. Spatially Distributed Characterization of Catchment Dynamics Using Travel-Time Distributions

    Science.gov (United States)

    Heße, F.; Zink, M.; Attinger, S.

    2015-12-01

    The description of storage and transport of both water and solved contaminants in catchments is very difficult due to the high heterogeneity of the subsurface properties that govern their fate. This heterogeneity, combined with a generally limited knowledge about the subsurface, results in high degrees of uncertainty. As a result, stochastic methods are increasingly applied, where the relevant processes are modeled as being random. Within these methods, quantities like the catchment travel or residence time of a water parcel are described using probability density functions (PDF). The derivation of these PDF's is typically done by using the water fluxes and states of the catchment. A successful application of such frameworks is therefore contingent on a good quantification of these fluxes and states across the different spatial scales. The objective of this study is to use travel times for the characterization of an ca. 1000 square kilometer, humid catchment in Central Germany. To determine the states and fluxes, we apply the mesoscale Hydrological Model mHM, a spatially distributed hydrological model to the catchment. Using detailed data of precipitation, land cover, morphology and soil type as inputs, mHM is able to determine fluxes like recharge and evapotranspiration and states like soil moisture as outputs. Using these data, we apply the above theoretical framework to our catchment. By virtue of the aforementioned properties of mHM, we are able to describe the storage and release of water with a high spatial resolution. This allows for a comprehensive description of the flow and transport dynamics taking place in the catchment. The spatial distribution of such dynamics is then compared with land cover and soil moisture maps as well as driving forces like precipitation and temperature to determine the most predictive factors. In addition, we investigate how non-local data like the age distribution of discharge flows are impacted by, and therefore allow to infer

  2. Flood modelling with a distributed event-based parsimonious rainfall-runoff model: case of the karstic Lez river catchment

    Directory of Open Access Journals (Sweden)

    M. Coustau

    2012-04-01

    Full Text Available Rainfall-runoff models are crucial tools for the statistical prediction of flash floods and real-time forecasting. This paper focuses on a karstic basin in the South of France and proposes a distributed parsimonious event-based rainfall-runoff model, coherent with the poor knowledge of both evaporative and underground fluxes. The model combines a SCS runoff model and a Lag and Route routing model for each cell of a regular grid mesh. The efficiency of the model is discussed not only to satisfactorily simulate floods but also to get powerful relationships between the initial condition of the model and various predictors of the initial wetness state of the basin, such as the base flow, the Hu2 index from the Meteo-France SIM model and the piezometric levels of the aquifer. The advantage of using meteorological radar rainfall in flood modelling is also assessed. Model calibration proved to be satisfactory by using an hourly time step with Nash criterion values, ranging between 0.66 and 0.94 for eighteen of the twenty-one selected events. The radar rainfall inputs significantly improved the simulations or the assessment of the initial condition of the model for 5 events at the beginning of autumn, mostly in September–October (mean improvement of Nash is 0.09; correction in the initial condition ranges from −205 to 124 mm, but were less efficient for the events at the end of autumn. In this period, the weak vertical extension of the precipitation system and the low altitude of the 0 °C isotherm could affect the efficiency of radar measurements due to the distance between the basin and the radar (~60 km. The model initial condition S is correlated with the three tested predictors (R2 > 0.6. The interpretation of the model suggests that groundwater does not affect the first peaks of the flood, but can strongly impact subsequent peaks in the case of a multi-storm event. Because this kind of model is based on a limited

  3. Using a semi distributed model to enhance communication with stakeholders and participation for designing nitrogen-efficient cropping systems in a catchment

    Science.gov (United States)

    Dupas, Rémi; Parnaudeau, Virginie; Reau, Raymond; Gascuel-Odoux, Chantal; Durand, Patrick

    2013-04-01

    Context Catchment scale fully distributed agro-hydrological models are often advocated to evaluate the effect of N mitigation plans on water quality. This type of model is well suited to predict nitrate concentration in rivers under different scenarios, thanks to the variety of processes considered (e.g. groundwater table fluctuations, retention by landscape structures). The role of stakeholders is often limited to providing input data for the modeling; participation only takes place when defining the scenarios to be tested (e.g. implementation of a regulation). In most cases, characterization of the cropping systems and their evolution is carried out by scientists alone based on data from surveys and external expert knowledge. For instance, crop succession on each field plot is determined using complex statistical methods or remote sensing data, generating a complex system description that is not always adapted to the stakeholder's issues. However, modeling with stakeholders at local scale enables increasing and sharing knowledge by collaborative learning. We assume that involving stakeholders in the characterization of the cropping systems to be modeled, and simplifying system description, helps performing modeling studies that answer their questions on design of N efficient cropping systems. The model Syst'N is a tool designed to increase knowledge on nitrogen losses in cropping systems, at the plot scale. This tool, beyond a mere simulation model, was developed in order to meet requirements and constraints of non scientific users such as local stakeholders involved in water quality actions. They are referred to as 'stakeholders' hereafter. In this simulation study, N losses at the outlet of the catchment result from an aggregation of losses simulated in 63 homogenous simulation units (HSU), representing cropping systems present in the catchment. Learnings from field experience with stakeholders The field experience described here is from a 80km² catchment

  4. Using Distributed, Integrated Hydrological Models to Simulate Water Balance Changes at the Hillslope and Catchment Scale Due to Fire Disturbances

    Science.gov (United States)

    Atchley, A. L.; Coon, E.; Trader, L.; Middleton, R. S.; Painter, S. L.; Kikinzon, E.

    2015-12-01

    Catastrophic wildfires have increased worldwide due in part to previous fire suppression efforts, but also climate change. These wildfires dramatically alter ecosystem structure resulting in lasting changes to hydrological characteristics including surface runoff and subsurface water storage. Most notably fire results in the removal of forest ground cover as well as much, if not all, of the forest vegetation that is responsible for precipitation interception and transpiration from the soil. The presence of ground cover is associated with high porosity, surface roughness and infiltration rates, which can contribute to greater soil water recharge. Modeling the hydrological changes due to fire requires representation of the vegetation changes along with near surface soil characteristics, particularly ground cover. Moreover, the coupled nature of surface and subsurface flow necessitates an integrated representation of variably saturated subsurface flow and overland flow to capture infiltration-limited runoff. Here pre- and post-catastrophic fire data collected from Bandelier National Monument is used to characterize ground cover and vegetation conditions used in coupled surface subsurface hydrologic models. This data is also used to develop appropriate representations of litter layers in the models. Changes in hydrologic regimes at the hillslope and catchment scale are simulated in response to measured precipitation events. Differences in both runoff generation and soil water storage are then described along a continuum of burn severity.

  5. Describing Ecosystem Complexity through Integrated Catchment Modeling

    Science.gov (United States)

    Shope, C. L.; Tenhunen, J. D.; Peiffer, S.

    2011-12-01

    Land use and climate change have been implicated in reduced ecosystem services (ie: high quality water yield, biodiversity, and agricultural yield. The prediction of ecosystem services expected under future land use decisions and changing climate conditions has become increasingly important. Complex policy and management decisions require the integration of physical, economic, and social data over several scales to assess effects on water resources and ecology. Field-based meteorology, hydrology, soil physics, plant production, solute and sediment transport, economic, and social behavior data were measured in a South Korean catchment. A variety of models are being used to simulate plot and field scale experiments within the catchment. Results from each of the local-scale models provide identification of sensitive, local-scale parameters which are then used as inputs into a large-scale watershed model. We used the spatially distributed SWAT model to synthesize the experimental field data throughout the catchment. The approach of our study was that the range in local-scale model parameter results can be used to define the sensitivity and uncertainty in the large-scale watershed model. Further, this example shows how research can be structured for scientific results describing complex ecosystems and landscapes where cross-disciplinary linkages benefit the end result. The field-based and modeling framework described is being used to develop scenarios to examine spatial and temporal changes in land use practices and climatic effects on water quantity, water quality, and sediment transport. Development of accurate modeling scenarios requires understanding the social relationship between individual and policy driven land management practices and the value of sustainable resources to all shareholders.

  6. Catchment mixing processes and travel time distributions

    National Research Council Canada - National Science Library

    Botter, Gianluca

    2012-01-01

    ...) of travel, residence and evapotranspiration times, which are comprehensive descriptors of the fate of rainfall water particles traveling through catchments, and provide key information on hydrologic...

  7. Integrated flow and temperature modeling at the catchment scale

    DEFF Research Database (Denmark)

    Loinaz, Maria Christina; Davidsen, Hasse Kampp; Butts, Michael

    2013-01-01

    , the Silver Creek Basin in Idaho, where stream temperature affects the populations of fish and other aquatic organisms. The model calibration highlights the importance of spatially distributed flow dynamics in the catchment to accurately predict stream temperatures. The results also show the value...... Creek over 0.3°C and 1.5°C, respectively. In spring-fed systems like Silver Creek, it is clearly not feasible to separate river habitat restoration from upstream catchment and groundwater management....

  8. Constitution of a catchment virtual observatory for sharing flow and transport models outputs

    Science.gov (United States)

    Thomas, Zahra; Rousseau-Gueutin, Pauline; Kolbe, Tamara; Abbott, Benjamin W.; Marçais, Jean; Peiffer, Stefan; Frei, Sven; Bishop, Kevin; Pichelin, Pascal; Pinay, Gilles; de Dreuzy, Jean-Raynald

    2016-12-01

    Predicting hydrological catchment behavior based on measurable (and preferably widely available) catchment characteristics has been one of the main goals of hydrological modelling. Residence time distributions provide synoptic information about catchment functioning and can be useful metrics to predict their behaviors. Moreover, residence time distributions highlight a wide range of characteristic scales (spatial and temporal) and mixing processes. However, catchment-specific heterogeneity means that the link between residence time distributions and catchment characteristics is complex. Investigating this link for a wide range of catchments could reveal the role of topography, geology, land-use, climate and other factors in controlling catchment hydrology. Meaningful comparison is often challenging given the diversity of data and model structures and formats. To address this need, we are introducing a new virtual platform called Catchment virtual Observatory for Sharing flow and transport models outputs (COnSOrT). The goal of COnSOrT is to promote catchment intercomparison by sharing calibrated model outputs. Compiling commensurable results in COnSOrT will help evaluate model performance, quantify inter-catchment controls on hydrology, and identify research gaps and priorities in catchment science. Researchers interested in sharing or using calibrated model results are invited to participate in the virtual observatory. Participants may test post-processing methods on a wide range of catchment environments to evaluate the generality of their findings.

  9. Soil organic carbon distribution in an agricultural catchment in Southern Brazil: from hillslope to catchment scale.

    Science.gov (United States)

    Trigalet, Sylvain; Chartin, Caroline; Van Oost, Kristof; van Wesemael, Bas

    2017-04-01

    Understanding the soil organic carbon (SOC) distribution a few decades after conversion to cropland and plantations in a hilly catchment in southern Brazil is challenging due to scale-dependent controlling factors. Firstly, SOC, bulk density (BD) and texture were measured by depth intervals along 18 soil profiles located in three topographical positions (sloping plateau, central back slope and concave foot slope) in cropland and forest with contrasting slopes. SOC stocks in concave footslope position were not significantly different between fields on steep (11.1 kg C m-2) and gentle slopes (12.8 kg C m-2). However, in eroding profiles, SOC stocks are twice as high in fields on gentle slopes (17.6/12.6 kg C m-2) compared to steep slopes (8.3/7.1 kg C m-2). SOC stocks on steep slope on cropland (8.8 kg C m-2) are three times lower than SOC stocks on steep slope under undisturbed forest (23.7 kg C m-2). On gentle slopes, the effect of deforestation on SOC stocks was not so drastic (14.3 and 14.4 kg C m-2). Therefore, contrasting topography generates different patterns of SOC redistribution in the catchment. The effect of conversion to cropland is probably due to soil redistribution by water and tillage erosion aggravated by the steep terrain. Secondly, in order to assess the heterogeneity of SOC distribution at catchment scale, samples were collected at 10-20; 40-50 and 75-85 cm in 167 soil profiles sampled with an auger. SOC concentrations (gC kg-1 ) in numerous bulk soil samples (n = 378) were predicted by VIS-NIR spectroscopy and partial least-square regression models. SOC stocks were assessed by a mass preserving spline tool by interpolating SOC mass at the three non-contiguous depth intervals. Samples of calibration-validation dataset (n = 95) were used for physical SOC fractionation allowing the measurement of carbon associated with correlation coefficients were used to assess the influence of several covariates on SOC stocks, SOC in bulk soil and fractions

  10. Examining runoff generation processes in the Selke catchment in central Germany: Insights from data and semi-distributed numerical model

    Directory of Open Access Journals (Sweden)

    Sumit Sinha

    2016-09-01

    New hydrological insights for the region: We examined the spatio-temporal variation of runoff generating mechanisms on the sub-basin level on seasonal basis. Our analysis reveals that the runoff generation in the Selke catchment is primarily dominated by shallow sub-surface flow and very rarely the contribution from Dunne overland flow exceeds sub-surface flow. Runoff generated by Hortonian mechanism is very infrequent and almost negligible. We also examined the spatio-temporal variation of runoff coefficients on seasonal basis as well as for individual storms. Due to higher precipitation and topographic relief in the upland catchment of Silberhutte, the runoff coefficients were consistently higher and its peak was found in winter months due to lower evapotranspiration.

  11. Distributed nitrate transport and reaction routines (NTR) inside the mesoscale Hydrological Model (mHM) framework: Development and Application in the Selke catchment

    Science.gov (United States)

    Sinha, Sumit; Rode, Michael; Kumar, Rohini; Yang, Xiaoqiang; Samaniego, Luis; Borchardt, Dietrich

    2016-04-01

    Precise measurements of where, when and how much denitrification occurs on the basis of measurements alone persist to be vexing and intractable research problem at all spatial and temporal scales. As a result, models have become essential and vital tools for furthering our current understanding of the processes that control denitrification on catchment scale. Emplacement of Water Framework Directive (WFD) and continued efforts in improving water treatment facilities has resulted in alleviating the problems associated with point sources of pollution. However, the problem of eutrophication still persists and is primarily associated with the diffused sources of pollution originating from agricultural area. In this study, the nitrate transport and reaction (NTR) routines are developed inside the distributed mesoscale Hydrological Model (mHM www.ufz.de/mhm) which is a fully distributed hydrological model with a novel parameter regionalization scheme (Samaniego et al. 2010; Kumar et al. 2013) and has been applied to whole Europe (Rakovec et al. 2016) and numerous catchments worldwide. The aforementioned NTR model is applied to a mesoscale river basin, Selke (463 km2) located in central Germany. The NTR model takes in account the critical and pertinent processes like transformation in vadose zone, atmospheric deposition, plant uptake, instream denitrification and also simulates the process of manure and fertilizer application. Both streamflow routines and the NTR model are run on daily time steps. The split-sample approach was used for model calibration (1994-1999) and validation (2000-2004). Flow dynamics at three gauging stations located inside this catchment are successfully captured by the model with consistently high Nash-Sutcliffe Efficiency (NSE) of at least 0.8. Regarding nitrate estimates, the NSE values are greater than 0.7 for both validation and calibration periods. Finally, the NTR model is used for identifying the critical source areas (CSAs) that contribute

  12. Modeling of matters removal from swampy catchment

    Science.gov (United States)

    Inishev, N. G.; Inisheva, L. I.

    2010-05-01

    the estimations were made taking into account layering unevenness of snow cover in deferent landscapes. Stored water distribution in the limits of every landscape was approximated by the curve of gamma distribution with parameters which are the results of snow survey. Everyday basin water yield was determined as difference between excesses of water coming above usage for filling of its water retaining tank. The size of the water retaining tank before start of snow melting depends on the basin wetting in the previous autumn. Autumn river flow is taken as a degree of water retaining tank filling before the snow melt. It is supposed that there is a process of water accumulation at slopes. Between theses water supplies and overland runoffs there is a nonlinear link. Temporary melt water detention, which comes from mire in swamp forest, is considered. Estimations are made individually for field, forest and swamp parts of the basin of the river Kljuch. Estimation of HA removal from the surface of catchment of the river Kljuch is taken as an example of model application. The results reveal possibilities of the given approach to modeling of dissolved matters removal from the swampy area. Acknowledgements: This research was supported by RFFR (No.No. 09-05-00235, 09-05-99007), Minister of education and science (No. 02.740.11.0325).

  13. Catchment modeling and model transferability in upper Blue Nile Basin, Lake Tana, Ethiopia

    Directory of Open Access Journals (Sweden)

    A. S. Gragne

    2008-03-01

    Full Text Available Understanding spatial and temporal distribution of water resources has an important role for water resource management. To understand water balance dynamics and runoff generation mechanisms at the Gilgel Abay catchment (a major tributary into lake Tana, source of Blue Nile, Ethiopia and to evaluate model transferability, catchment modeling was conducted using the conceptual hydrological model HBV. The catchment of the Gigel Abay was sub-divided into two gauged sub-catchments (Upper Gilgel Abay, UGASC, and Koga, KSC and one ungauged sub-catchment.

    Manual calibration of the daily models for three different catchment representations (CRs: (i lumped, (ii lumped with multiple vegetation zones, and (iii semi-distributed with vegetations zone and elevation zones, showed good to satisfactory model performance (Nash-Sutcliffe efficiency values, Reff>0.75 and >0.6, respectively, for UGASC and KSC. The change of the time step to fifteen and thirty days resulted in very good model performances in both sub-catchments (Reff>0.8. The model parameter transferability tests conducted on the daily models showed poor performance in both sub-catchments, whereas the fifteen and thirty days models yielded high Reff values using transferred parameter sets. This together with the sensitivity analysis carried out after Monte Carlo simulations (1 000 000 model runs per CR explained the reason behind the difference in hydrologic behaviors of the two sub-catchments UGASC and KSC. The dissimilarity in response pattern of the sub-catchments was caused by the presence of dambos in KSC and differences in the topography between UGASC and KSC. Hence, transferring model parameters from the view of describing hydrological process was found to be not feasible for all models. On the other hand, from a water resources management perspective the results obtained by transferring parameters of the larger time step model were

  14. Assessment of surface water resources availability using catchment modelling and the results of tracer studies in the mesoscale Migina Catchment, Rwanda

    NARCIS (Netherlands)

    Munyaneza, O.; Mukubwa, A.; Maskey, S.; Uhlenbrook, S.; Wenninger, J.W.

    2014-01-01

    In the present study, we developed a catchment hydrological model which can be used to inform water resources planning and decision making for better management of the Migina Catchment (257.4 km2). The semi-distributed hydrological model HEC-HMS (Hydrologic Engineering Center – the Hydrologic Modell

  15. An efficient method for applying a differential equation to deriving the spatial distribution of specific catchment area from gridded digital elevation models

    Science.gov (United States)

    Qin, Cheng-Zhi; Ai, Bei-Bei; Zhu, A.-Xing; Liu, Jun-Zhi

    2017-03-01

    Deriving the spatial distribution of specific catchment area (SCA) from a gridded digital elevation model (DEM) is one of the most important issues in digital terrain analysis. Conventional methods usually estimate SCA for each cell using a flow direction algorithm, but the results obtained are often unsatisfactory. Recently, Gallant and Hutchinson (2011, Water Resources Research, 47(5), W05535) proposed a differential equation which quantifies the change of SCA along a slope line, and thus the numerical solution of SCA at any point on a surface can be calculated accurately by integrating the differential equation. However, obtaining the numerical SCA solution based on this differential equation is so computationally intensive that it is too time-consuming to use it to derive the overall SCA spatial distribution from a gridded DEM. In this study, we developed a parallel algorithm based on OpenMP to make the numerical SCA solution based on Gallant and Hutchinson (2011)'s differential equation practical to derive the spatial distribution of SCA from a gridded DEM. Experiments based on two artificial surfaces with theoretical SCA and a more complex real terrain surface demonstrated that the proposed parallel algorithm obtained satisfactory acceleration performance and a much lower error than the MFD-md algorithm, which is a representative of conventional grid-based flow direction algorithms. Due to the speedup effects of the proposed parallel algorithm, we analyzed the effects of the DEM grid size and integration step length on the numerical SCA solution in detailed experiments. The experimental results suggested that the proposed algorithm performed best normally at the resolution of 5 m. A step ratio of 0.5 is suitable in applications of the proposed parallel algorithm.

  16. Integrating Local Scale Drainage Measures in Meso Scale Catchment Modelling

    Directory of Open Access Journals (Sweden)

    Sandra Hellmers

    2017-01-01

    Full Text Available This article presents a methodology to optimize the integration of local scale drainage measures in catchment modelling. The methodology enables to zoom into the processes (physically, spatially and temporally where detailed physical based computation is required and to zoom out where lumped conceptualized approaches are applied. It allows the definition of parameters and computation procedures on different spatial and temporal scales. Three methods are developed to integrate features of local scale drainage measures in catchment modelling: (1 different types of local drainage measures are spatially integrated in catchment modelling by a data mapping; (2 interlinked drainage features between data objects are enabled on the meso, local and micro scale; (3 a method for modelling multiple interlinked layers on the micro scale is developed. For the computation of flow routing on the meso scale, the results of the local scale measures are aggregated according to their contributing inlet in the network structure. The implementation of the methods is realized in a semi-distributed rainfall-runoff model. The implemented micro scale approach is validated with a laboratory physical model to confirm the credibility of the model. A study of a river catchment of 88 km2 illustrated the applicability of the model on the regional scale.

  17. Hydrological Modelling of Small Catchments Using Swat

    Science.gov (United States)

    Kannan, N.; White, S. M.; Worrall, F.; Groves, S.

    The data from a 142ha catchment in Eastern England(Colworth, Bedfordshire)are be- ing used to investigate the performance of the USDA SWAT software for modelling hydrology of small catchments. Stream flow at the catchment outlet has been mon- itored since October 1999. About 50% of the total catchment is directly controlled within one farm and a rotation of wheat, oil seed rape, grass, linseed, beans and peas is grown. Three years of stream flow and climate data are available. Calibration and validation of stream flow was carried out with both runoff modelling options in the SWAT model (USDA curve number method and the Green and Ampt method). The Nash and Sutcliffe efficiencies for the calibration period were 66% and 63% respec- tively. The performance of SWAT was better in the validation period as a whole, with regard to timing of peaks, baseflow values and Nash and Sutcliffe efficiency. An ef- ficiency of 70% was obtained using the curve number method, which is comparable with the efficiencies obtainable with more complex models. Despite this performance, SWAT is under predicting stream flow peaks. A detailed investigation of important model components, has allowed us to identify some of the reasons for under predic- tion of stream flow peaks.

  18. Effect of the spatial distribution of physical aquifer properties on modelled water table depth and stream discharge in a headwater catchment

    Directory of Open Access Journals (Sweden)

    C. Gascuel-Odoux

    2010-07-01

    Full Text Available Water table depth and its dynamics on hillslopes are often poorly predicted despite they control both water transit time within the catchment and solute fluxes at the catchment outlet. This paper analyses how relaxing the assumption of lateral homogeneity of physical properties can improve simulations of water table depth and dynamics. Four different spatial models relating hydraulic conductivity to topography have been tested: a simple linear relationship, a linear relationship with two different topographic indexes, two Ks domains with a transitional area. The Hill-Vi model has been modified to test these hypotheses. The studied catchment (Kervidy-Naizin, Western France is underlain by schist crystalline bedrock. A shallow and perennial groundwater highly reactive to rainfall events mainly develops in the weathered saprolite layer. The results indicate that (1 discharge and the water table in the riparian zone are similarly predicted by the four models, (2 distinguishing two Ks domains constitutes the best model and slightly improves prediction of the water table upslope, and (3 including spatial variations in the other parameters such as porosity or rate of hydraulic conductivity decrease with depth does not improve the results. These results underline the necessity of better investigations of upslope areas in hillslope hydrology.

  19. Assessment of surface water resources availability using catchment modelling and the results of tracer studies in the mesoscale Migina Catchment, Rwanda

    NARCIS (Netherlands)

    Munyaneza, O.; Mukubwa, A.; Maskey, S.; Uhlenbrook, S.; Wenninger, J.W.

    2014-01-01

    In the present study, we developed a catchment hydrological model which can be used to inform water resources planning and decision making for better management of the Migina Catchment (257.4 km2). The semi-distributed hydrological model HEC-HMS (Hydrologic Engineering Center – the Hydrologic

  20. Improving Distributed Runoff Prediction in Urbanized Catchments with Remote Sensing based Estimates of Impervious Surface Cover

    Science.gov (United States)

    Chormanski, Jaroslaw; Van de Voorde, Tim; De Roeck, Tim; Batelaan, Okke; Canters, Frank

    2008-01-01

    The amount and intensity of runoff on catchment scale are strongly determined by the presence of impervious land-cover types, which are the predominant cover types in urbanized areas. This paper examines the impact of different methods for estimating impervious surface cover on the prediction of peak discharges, as determined by a fully distributed rainfall-runoff model (WetSpa), for the upper part of the Woluwe River catchment in the southeastern part of Brussels. The study shows that detailed information on the spatial distribution of impervious surfaces, as obtained from remotely sensed data, produces substantially different estimates of peak discharges than traditional approaches based on expert judgment of average imperviousness for different types of urban land use. The study also demonstrates that sub-pixel estimation of imperviousness may be a useful alternative for more expensive high-resolution mapping for rainfall-runoff modelling at catchment scale.

  1. Can spatial statistical river temperature models be transferred between catchments?

    Science.gov (United States)

    Jackson, Faye L.; Fryer, Robert J.; Hannah, David M.; Malcolm, Iain A.

    2017-09-01

    There has been increasing use of spatial statistical models to understand and predict river temperature (Tw) from landscape covariates. However, it is not financially or logistically feasible to monitor all rivers and the transferability of such models has not been explored. This paper uses Tw data from four river catchments collected in August 2015 to assess how well spatial regression models predict the maximum 7-day rolling mean of daily maximum Tw (Twmax) within and between catchments. Models were fitted for each catchment separately using (1) landscape covariates only (LS models) and (2) landscape covariates and an air temperature (Ta) metric (LS_Ta models). All the LS models included upstream catchment area and three included a river network smoother (RNS) that accounted for unexplained spatial structure. The LS models transferred reasonably to other catchments, at least when predicting relative levels of Twmax. However, the predictions were biased when mean Twmax differed between catchments. The RNS was needed to characterise and predict finer-scale spatially correlated variation. Because the RNS was unique to each catchment and thus non-transferable, predictions were better within catchments than between catchments. A single model fitted to all catchments found no interactions between the landscape covariates and catchment, suggesting that the landscape relationships were transferable. The LS_Ta models transferred less well, with particularly poor performance when the relationship with the Ta metric was physically implausible or required extrapolation outside the range of the data. A single model fitted to all catchments found catchment-specific relationships between Twmax and the Ta metric, indicating that the Ta metric was not transferable. These findings improve our understanding of the transferability of spatial statistical river temperature models and provide a foundation for developing new approaches for predicting Tw at unmonitored locations across

  2. River network bedload model: a tool to investigate the impact of flow regulation on grain size distribution in a large Alpine catchment

    Science.gov (United States)

    Costa, Anna; Molnar, Peter

    2017-04-01

    Sediment transport rates along rivers and the grain size distribution (GSD) of coarse channel bed sediment are the result of the long term balance between transport capacity and sediment supply. Transport capacity, mainly a function of channel geometry and flow competence, can be altered by changes in climatic forcing as well as by human activities. In Alpine rivers it is hydropower production systems that are the main causes of modification to the transport capacity of water courses through flow regulation, leading over longer time scales to the adjustment of river bed GSDs. We developed a river network bedload transport model to evaluate the impacts of hydropower on the transfer of sediments and the GSDs of the Upper Rhône basin, a 5,200 km2 catchment located in the Swiss Alps. Many large reservoirs for hydropower production have been built along the main tributaries of the Rhône River since the 1960s, resulting in a complex system of intakes, tunnels, and pumping stations. Sediment storage behind dams and intakes, is accompanied by altered discharge due to hydropower operations, mainly higher flow in winter and lower in summer. It is expected that this change in flow regime may have resulted in different bedload transport. However, due the non-linear, threshold-based nature of the relation between discharge and sediment mobilization, the effects of changed hydraulic conditions are not easily deducible, and because observations of bedload in pre- and post-dam conditions are usually not available, a modelling approach is often necessary. In our modelling approach, the river network is conceptualized as a series of connected links (river reaches). Average geometric characteristics of each link (width, length, and slope of cross section) are extracted from digital elevation data, while surface roughness coefficients are assigned based on the GSD. Under the assumptions of rectangular prismatic cross sections and normal flow conditions, bed shear stress is estimated

  3. In Lieu of the Paired-Catchment Approach - Hydrologic Model Change Detection at the Catchment Scale

    Science.gov (United States)

    Zegre, N. P.

    2009-05-01

    Knowledge of the effects of forest management on hydrology primarily comes from paired-catchment studies conducted world-wide. While this approach has been useful for discerning changes in small experimental catchments and has contributed fundamental knowledge of the effects of forest and natural resources management on hydrology, results from experimental catchment studies exhibit temporal variability, have limited spatial inference, and lack insight into internal catchment processes. To address these limitations, traditional field experiments can be supplemented with numerical models to isolate the effects of disturbance on catchment behavior. Outlined in this study is an alternative method of change detection for daily time-series streamflow that integrates hydrologic modeling and statistical change detection methods used to discern the effects of contemporary forest management on the hydrology of western Oregon Cascades headwater catchments. In this study, a simple rainfall-runoff model was used to generate virtual reference catchments using attributes that reflect streamflow conditions absent of forest disturbance. Streamflow was simulated under three levels of model uncertainty using GLUE and were used to construct generalized least squares regression models to discern changes in hydrologic behavior. By considering processes within a single experimental catchment rather than the two spatially explicit catchments used in traditional paired experiments, it was possible to reduce unexplained variation and increase the likelihood of correctly detecting hydrologic effects following forest harvesting. In order to evaluate the stability of the hydrologic and statistical models and catchment behavior over time, the change detection method was applied to a contemporary reference catchment. By applying the change detection model to reference catchments, it was possible to eliminate unexpected variation as a cause for detected changes in observed hydrology. Further, it

  4. Effects of model structure and catchment discretization on discharge simulation in a small forest catchment

    Science.gov (United States)

    Spieler, Diana; Schwarze, Robert; Schütze, Niels

    2017-04-01

    In the past a variety of different modeling approaches has been developed in catchment hydrology. Even though there is no argument on the relevant processes taking place, there is no unified theory on how best to represent them computationally. Thus a vast number of models has been developed, varying from lumped models to physically based models. Most of them have a more or less fixed model structure and follow the "one fits all" paradigm. However, a more flexible approach could improve model realism by designing catchment specific model structures based on data availability. This study focuses on applying the flexible hydrological modelling framework RAVEN (Craig et al., 2013), to systematically test several conceptual model structures on the 19 km2 Große Ohe Catchment in the Bavarian Forest (Germany). By combining RAVEN with the DREAM algorithm (Vrugt et al., 2009), the relationship between catchment characteristics, model structure, parameter uncertainty and data availability are analyzed. The model structure is progressively developed based on the available data of the well observed forested catchment area. In a second step, the impact of the catchment discretization is analyzed by testing different spatial resolutions of topographic input data.

  5. Geographically Isolated Wetlands and Catchment Hydrology: A Modified Model Analyses

    Science.gov (United States)

    Evenson, G.; Golden, H. E.; Lane, C.; D'Amico, E.

    2014-12-01

    Geographically isolated wetlands (GIWs), typically defined as depressional wetlands surrounded by uplands, support an array of hydrological and ecological processes. However, key research questions concerning the hydrological connectivity of GIWs and their impacts on downgradient surface waters remain unanswered. This is particularly important for regulation and management of these systems. For example, in the past decade United States Supreme Court decisions suggest that GIWs can be afforded protection if significant connectivity exists between these waters and traditional navigable waters. Here we developed a simulation procedure to quantify the effects of various spatial distributions of GIWs across the landscape on the downgradient hydrograph using a refined version of the Soil and Water Assessment Tool (SWAT), a catchment-scale hydrological simulation model. We modified the SWAT FORTRAN source code and employed an alternative hydrologic response unit (HRU) definition to facilitate an improved representation of GIW hydrologic processes and connectivity relationships to other surface waters, and to quantify their downgradient hydrological effects. We applied the modified SWAT model to an ~ 202 km2 catchment in the Coastal Plain of North Carolina, USA, exhibiting a substantial population of mapped GIWs. Results from our series of GIW distribution scenarios suggest that: (1) Our representation of GIWs within SWAT conforms to field-based characterizations of regional GIWs in most respects; (2) GIWs exhibit substantial seasonally-dependent effects upon downgradient base flow; (3) GIWs mitigate peak flows, particularly following high rainfall events; and (4) The presence of GIWs on the landscape impacts the catchment water balance (e.g., by increasing groundwater outflows). Our outcomes support the hypothesis that GIWs have an important catchment-scale effect on downgradient streamflow.

  6. Flow processes on the catchment scale - modeling of initial structural states and hydrological behavior in an artificial exemplary catchment

    Science.gov (United States)

    Maurer, Thomas; Caviedes-Voullième, Daniel; Hinz, Christoph; Gerke, Horst H.

    2017-04-01

    Landscapes that are heavily disturbed or newly formed by either natural processes or human activity are in a state of disequilibrium. Their initial development is thus characterized by highly dynamic processes under all climatic conditions. The primary distribution and structure of the solid phase (i.e. mineral particles forming the pore space) is one of the decisive factors for the development of hydrological behavior of the eco-hydrological system and therefore (co-) determining for its - more or less - stable final state. The artificially constructed ‚Hühnerwasser' catchment (a 6 ha area located in the open-cast lignite mine Welzow-Süd, southern Brandenburg, Germany) is a landscape laboratory where the initial eco-hydrological development is observed since 2005. The specific formation (or construction) processes generated characteristic sediment structures and distributions, resulting in a spatially heterogeneous initial state of the catchment. We developed a structure generator that simulates the characteristic distribution of the solid phase for such constructed landscapes. The program is able to generate quasi-realistic structures and sediment compositions on multiple spatial levels (1 cm up to 100 m scale). The generated structures can be i) conditioned to actual measurement values (e.g., soil texture and bulk distribution); ii) stochastically generated, and iii) calculated deterministically according to the geology and technical processes at the excavation site. Results are visualized using the GOCAD software package and the free software Paraview. Based on the 3D-spatial sediment distributions, effective hydraulic van-Genuchten parameters are calculated using pedotransfer functions. The hydraulic behavior of different sediment distribution (i.e. versions or variations of the catchment's porous body) is calculated using a numerical model developed by one of us (Caviedes-Voullième). Observation data are available from catchment monitoring are available

  7. Modelling the effect of wildfire on forested catchment water quality using the SWAT model

    Science.gov (United States)

    Yu, M.; Bishop, T.; van Ogtrop, F. F.; Bell, T.

    2016-12-01

    Wildfire removes the surface vegetation, releases ash, increase erosion and runoff, and therefore effects the hydrological cycle of a forested water catchment. It is important to understand chnage and how the catchment recovers. These processes are spatially sensitive and effected by interactions between fire severity and hillslope, soil type and surface vegetation conditions. Thus, a distributed hydrological modelling approach is required. In this study, the Soil and Water Analysis Tool (SWAT) is used to predict the effect of 2001/02 Sydney wild fire on catchment water quality. 10 years pre-fire data is used to create and calibrate the SWAT model. The calibrated model was then used to simulate the water quality for the 10 years post-fire period without fire effect. The simulated water quality data are compared with recorded water quality data provided by Sydney catchment authority. The mean change of flow, total suspended solid, total nitrate and total phosphate are compare on monthly, three month, six month and annual basis. Two control catchment and three burn catchment were analysed.

  8. Influences on flood frequency distributions in Irish river catchments

    Science.gov (United States)

    Ahilan, S.; O'Sullivan, J. J.; Bruen, M.

    2012-04-01

    This study explores influences on flood frequency distributions in Irish rivers. A Generalised Extreme Value (GEV) type I distribution is recommended in Ireland for estimating flood quantiles in a single site flood frequency analysis. This paper presents the findings of an investigation that identified the GEV statistical distributions that best fit the annual maximum (AM) data series extracted from 172 gauging stations of 126 rivers in Ireland. Analysis of these data was undertaken to explore hydraulic and hydro-geological factors that influence flood frequency distributions. A hierarchical approach of increasing statistical power that used probability plots, moment and L-moment diagrams, the Hosking goodness of fit algorithm and a modified Anderson-Darling (A-D) statistical test was followed to determine whether a type I, type II or type III distribution was valid. Results of the Hosking et al. method indicated that of the 143 stations with flow records exceeding 25 yr, data for 95 (67%) was best represented by GEV type I distributions and a further 9 (6%) and 39 (27%) stations followed type II and type III distributions respectively. Type I, type II and type III distributions were determined for 83 (58%), 16 (11%) and 34 (24%) stations respectively using the modified A-D method (data from 10 stations was not represented by GEV family distributions). The influence of karst terrain on these flood frequency distributions was assessed by incorporating results on an Arc-GIS platform showing karst features and using Monte Carlo simulations to assess the significance of the number and clustering of the observed distributions. Floodplain effects were identified by using two-sample t-tests to identify statistical correlations between the distributions and catchment properties that are indicative of strong floodplain activity. The data reveals that type I distributions are spatially well represented throughout the country. While also well represented throughout the

  9. Influences on flood frequency distributions in Irish river catchments

    Directory of Open Access Journals (Sweden)

    S. Ahilan

    2012-04-01

    Full Text Available This study explores influences on flood frequency distributions in Irish rivers. A Generalised Extreme Value (GEV type I distribution is recommended in Ireland for estimating flood quantiles in a single site flood frequency analysis. This paper presents the findings of an investigation that identified the GEV statistical distributions that best fit the annual maximum (AM data series extracted from 172 gauging stations of 126 rivers in Ireland. Analysis of these data was undertaken to explore hydraulic and hydro-geological factors that influence flood frequency distributions. A hierarchical approach of increasing statistical power that used probability plots, moment and L-moment diagrams, the Hosking goodness of fit algorithm and a modified Anderson-Darling (A-D statistical test was followed to determine whether a type I, type II or type III distribution was valid. Results of the Hosking et al. method indicated that of the 143 stations with flow records exceeding 25 yr, data for 95 (67% was best represented by GEV type I distributions and a further 9 (6% and 39 (27% stations followed type II and type III distributions respectively. Type I, type II and type III distributions were determined for 83 (58%, 16 (11% and 34 (24% stations respectively using the modified A-D method (data from 10 stations was not represented by GEV family distributions. The influence of karst terrain on these flood frequency distributions was assessed by incorporating results on an Arc-GIS platform showing karst features and using Monte Carlo simulations to assess the significance of the number and clustering of the observed distributions. Floodplain effects were identified by using two-sample t-tests to identify statistical correlations between the distributions and catchment properties that are indicative of strong floodplain activity. The data reveals that type I distributions are spatially well represented throughout the country. While also well represented throughout

  10. High resolution modeling of a small urban catchment

    Science.gov (United States)

    Skouri-Plakali, Ilektra; Ichiba, Abdellah; Gires, Auguste; Tchiguirinskaia, Ioulia; Schertzer, Daniel

    2016-04-01

    Flooding is one of the most complex issues that urban environments have to deal with. In France, flooding remains the first natural risk with 72% of decrees state of natural disaster issued between October 1982 and mid-November 2014. Flooding is a result of meteorological extremes that are usually aggravated by the hydrological behavior of urban catchments and human factors. The continuing urbanization process is indeed changing the whole urban water cycle by limiting the infiltration and promoting runoff. Urban environments are very complex systems due to their extreme variability, the interference between human activities and natural processes but also the effect of the ongoing urbanization process that changes the landscape and hardly influences their hydrologic behavior. Moreover, many recent works highlight the need to simulate all urban water processes at their specific temporal and spatial scales. However, considering urban catchments heterogeneity still challenging for urban hydrology, even after advances noticed in term of high-resolution data collection and computational resources. This issue is more to be related to the architecture of urban models being used and how far these models are ready to take into account the extreme variability of urban catchments. In this work, high spatio-temporal resolution modeling is performed for a small and well-equipped urban catchment. The aim of this work is to identify urban modeling needs in terms of spatial and temporal resolution especially for a very small urban area (3.7 ha urban catchment located in the Perreux-sur-Marne city at the southeast of Paris) MultiHydro model was selected to carry out this work, it is a physical based and fully distributed model that interacts four existing modules each of them representing a portion of the water cycle in urban environments. MultiHydro was implemented at 10m, 5m and 2m resolution. Simulations were performed at different spatio-temporal resolutions and analyzed with

  11. Modelling runoff dynamics from information on river network and shape of catchment area

    Science.gov (United States)

    Skaugen, T.

    2009-12-01

    In a new approach, the dynamics of discharge is derived from the distribution of distances to the nearest river reach within a natural catchment. The river network and the shape of catchment provide a unique distribution function for each catchment which can be determined from a GIS. The distribution can be considered as a detailed description of the drainage density, where the location of the river relative to the catchment is taken into account. Within a fixed time interval, water flows through the catchment a certain distance which defines a fractional area. This fraction is estimated as an area enveloping the river network, whose width, perpendicular to the river network, is determined for the time interval of interest by the flow velocity. For a constant flow velocity, the time steps define adjacent areas which , for a sufficient number of time intervals, cover the entire catchment. For different flow velocities, we have different horizontal layers and the total discharge is the sum of discharge from each of the layers for each time step. The proposed principle for modelling the dynamics of discharge is implemented in the Swedish HBV model. The new model, named 3D (distance distribution dynamics), has the same precision as the HBV model but requires fewer parameters and represents thus a step in the right direction for meeting the challenge of predictions in ungauged basins.

  12. Curvature distribution within hillslopes and catchments and its effect on the hydrological response

    Directory of Open Access Journals (Sweden)

    P. W. Bogaart

    2006-06-01

    Full Text Available Topographic convergence and divergence are first order controls on the hillslope and catchment hydrological response, as evidenced by similarity parameter analyses. Hydrological models often do not take convergence as measured by contour curvature directly into account; instead they use comparable measures like the topographic index or the hillslope width function. This paper focusses on the question how hillslope width functions and contour curvature are related within the Plynlimon catchments, Wales. It is shown that the total width function of all hillslopes suggest that the catchments are overall divergent, which is in contrast to the perception that catchments should be overall convergent. This so-called convergence paradox is explained by the effect of skewed curvature distributions and extreme curvatures near the channel network. The hillslope-storage Boussinesq (hsB model is used to asses the effect of within-hillslope convergence variability on the hydrological response. It is concluded that this effect is small, even when the soil saturation threshold is exceeded. Also described in this paper is a novel algorithm to compute flow path lengths on hillslopes towards the drainage network, using the multiple-flow-direction method.

  13. Curvature distribution within hillslopes and catchments and its effect on the hydrological response

    Directory of Open Access Journals (Sweden)

    P. W. Bogaart

    2006-01-01

    Full Text Available Topographic convergence and divergence are first order controls on the hillslope and catchment hydrological response, as evidenced by similarity parameter analyses. Hydrological models often do not take convergence as measured by contour curvature directly into account; instead they use comparable measures like the topographic index, or the hillslope width function. This paper focuses on the question how hillslope width functions and contour curvature are related within the Plynlimon catchments, Wales. It is shown that the total width function of all hillslopes combined suggest that the catchments are divergent in overall shape, which is in contrast to the perception that catchments should be overall convergent. This so-called convergence paradox is explained by the effect of skewed curvature distributions and extreme curvatures near the channel network. The hillslope-storage Bossiness (hsB model is used to asses the effect of within-hillslope convergence variability on the hydrological response. It is concluded that this effect is small, even when the soil saturation threshold is exceeded. Also described in this paper is a novel algorithm to compute flow path lengths on hillslopes towards the drainage network, using the multidirectional flow redistribution method.

  14. Modelling the initial structure dynamics of soil and sediment exemplified for a constructed hydrological catchment

    Science.gov (United States)

    Maurer, Thomas; Schneider, Anna; Gerke, Horst H.

    2014-05-01

    Knowledge about spatial heterogeneity is of essential for the analysis of the hydrological catchment behavior. Heterogeneity is directly related to the distribution of the solid phase, and in initial hydrological systems, the solid phase is mainly composed of mineral particles. In artificial catchments, such sediment structures relate to the applied construction technology. It is supposed that the development of catchment ecosystems is strongly influenced by such specific initial spatial distributions of the solid phase. Moreover, during the initial development period, the primary structures in a catchment are altered rapidly by translocation processes, thereby subdividing the initial system in different compartments. Questions are: How does initial sediment distribution affect further structural development? How is catchment hydrology influenced by the initial structural development? What structures have a relevant impact on catchment-scale hydrological behavior? We present results from a structural modelling approach using a process-based structure generator program. The constructed hydrological catchment 'Hühnerwasser' (Lower Lusatia, Brandenburg, Germany) served exemplarily for the model development. A set of scenarios was created describing possible initial heterogeneities of the catchment. Both the outcrop site from where the parent material was excavated and the specific excavation procedures were considered in the modelling approach. Generated distributions are incorporated in a gridded 3D volume model constructed with the GOCAD software. Results were evaluated by semivariogram analysis and by quantifying point-to-point deviations. We also introduce a modelling conception for simulating the highly dynamic initial structural change, based on the generated initial distributions. We present a strategy on how to develop the initial structure generator into an integrative tool in order to (i) simulate and analyse the spatio-temporal development dynamics

  15. Physically, Fully-Distributed Hydrologic Simulations Driven by GPM Satellite Rainfall over an Urbanizing Arid Catchment in Saudi Arabia

    Directory of Open Access Journals (Sweden)

    Hatim O. Sharif

    2017-02-01

    Full Text Available A physically-based, distributed-parameter hydrologic model was used to simulate a recent flood event in the city of Hafr Al Batin, Saudi Arabia to gain a better understanding of the runoff generation and spatial distribution of flooding. The city is located in a very arid catchment. Flooding of the city is influenced by the presence of three major tributaries that join the main channel in and around the heavily urbanized area. The Integrated Multi-satellite Retrievals for Global Precipitation Measurement Mission (IMERG rainfall product was used due to lack of detailed ground observations. To overcome the heavy computational demand, the catchment was divided into three sub-catchments with a variable model grid resolution. The model was run on three subcatchments separately, without losing hydrologic connectivity among the sub-catchments. Uncalibrated and calibrated satellite products were used producing different estimates of the predicted runoff. The runoff simulations demonstrated that 85% of the flooding was generated in the urbanized portion of the catchments for the simulated flood. Additional model simulations were performed to understand the roles of the unique channel network in the city flooding. The simulations provided insights into the best options for flood mitigation efforts. The variable model grid size approach allowed using physically-based, distributed models—such as the Gridded Surface Subsurface Hydrologic Analysis (GSSHA model used in this study—on large basins that include urban centers that need to be modeled at very high resolutions.

  16. Influences on flood frequency distributions in Irish river catchments

    Directory of Open Access Journals (Sweden)

    S. Ahilan

    2011-04-01

    presence of karst in river catchments would be expected to provide additional subsurface storage and in this regard, type III distributions might be expected. The prevalence of type II distributions in this area reflects the finite nature of this storage and the effects, in extreme conditions, when the karst is saturated and further storage is no longer available. Results therefore indicate that in some instances assuming type I distributions is incorrect and may result in erroneous estimates of flood quantiles in these regions. Where actual data follows a type II distribution, flood quantiles may be underestimated and for type III distributions, overestimates may be expected.

  17. Exploring calibration strategies of the SEDD model in two olive orchard catchments

    Science.gov (United States)

    Burguet, María; Taguas, Encarnación V.; Gómez, José Alfonso

    2017-08-01

    To optimize soil conservation strategies in catchments, it is required an accurate diagnosis of the areas contributing to soil erosion by using models such as SEDD (Sediment Delivery Distributed model). In this study, different calibration strategies of the SEDD model were explored to adapt its use in two olive catchments with different environmental features and managements. A data series of rainfall-runoff-sediment load, collected in the catchments for 6 years was used: i) to evaluate calibration strategies for different management and flow conditions through the analysis of the C and R factors, and ii) to describe the temporal patterns of sediment delivery ratio (SDR) at the event and annual scales. Different results and calibration approaches were derived from contrasting soil features and sediment dynamics in the catchments. A good model performance with simple calibration procedure was obtained for the catchment with clayey soil and a very active gully, whereas the model parameterisation was adapted to event features in the catchment with sandy soil where the importance of concentrated flow was minor. Mean annual values of SDR at the watershed scale (SDRw) were 110.1% for the catchment with clayey soil and 64.1% for that with sandy soils. SDRw values greater than 100% occurred in very humid years with precipitations 30% above the mean annual values. At the event scale, similar behaviours of SDR were observed. SDR > 100% were associated with the gully exporting sediments out from the clayey catchment, whereas this was done by rills and an ephemeral gully in the sandy catchment.

  18. Comparative analysis of the PRMS and J2000 hydrological models applied to the Sandspruit Catchment, Western Cape, South Africa

    CSIR Research Space (South Africa)

    Bugan, Richard DH

    2009-12-01

    Full Text Available The applicability of distributed hydrological models to the semi-arid conditions in the Western Cape was investigated through the application of PRMS and J2000 in the Sandspruit Catchment. The Sandspruit is an annual river, with the catchment...

  19. A catchment scale water balance model for FIFE

    Science.gov (United States)

    Famiglietti, J. S.; Wood, E. F.; Sivapalan, M.; Thongs, D. J.

    1992-01-01

    A catchment scale water balance model is presented and used to predict evaporation from the King's Creek catchment at the First ISLSCP Field Experiment site on the Konza Prairie, Kansas. The model incorporates spatial variability in topography, soils, and precipitation to compute the land surface hydrologic fluxes. A network of 20 rain gages was employed to measure rainfall across the catchment in the summer of 1987. These data were spatially interpolated and used to drive the model during storm periods. During interstorm periods the model was driven by the estimated potential evaporation, which was calculated using net radiation data collected at site 2. Model-computed evaporation is compared to that observed, both at site 2 (grid location 1916-BRS) and the catchment scale, for the simulation period from June 1 to October 9, 1987.

  20. A catchment scale water balance model for FIFE

    Science.gov (United States)

    Famiglietti, J. S.; Wood, E. F.; Sivapalan, M.; Thongs, D. J.

    1992-01-01

    A catchment scale water balance model is presented and used to predict evaporation from the King's Creek catchment at the First ISLSCP Field Experiment site on the Konza Prairie, Kansas. The model incorporates spatial variability in topography, soils, and precipitation to compute the land surface hydrologic fluxes. A network of 20 rain gages was employed to measure rainfall across the catchment in the summer of 1987. These data were spatially interpolated and used to drive the model during storm periods. During interstorm periods the model was driven by the estimated potential evaporation, which was calculated using net radiation data collected at site 2. Model-computed evaporation is compared to that observed, both at site 2 (grid location 1916-BRS) and the catchment scale, for the simulation period from June 1 to October 9, 1987.

  1. Index models to evaluate the risk of phosphorus and nitrogen loss at catchment scales.

    Science.gov (United States)

    Drewry, J J; Newham, L T H; Greene, R S B

    2011-03-01

    This paper investigates index models as a tool to estimate the risk of N and P source strengths and loss at the catchment scale. The index models assist managers in improving the focus of remediation actions that reduce nutrient delivery to waterbodies. N and P source risk factors (e.g. soil nutrient concentrations) and transport risk factors (e.g. distance-to-streams) are used to determine the overall risk of nutrient loss for a case study in the Tuross River catchment of coastal southeast Australia. In the development of the N index model for Tuross, particulate N was considered important based on the observed event water quality data. In contrast to previous N index models, erosion and contributing distance were therefore included in the Tuross River catchment N index. Event-based water quality monitoring, and soil information, or in data-poor catchments conceptual understanding, are essential to represent catchment-scale processes. The techniques have high applicability in other catchments, and are complementary to other modelling techniques such as process-based semi-distributed modelling. Index models generally provide much more detailed spatial resolution than fully- or semi-distributed conceptual modelling approaches. Semi-distributed models can be used to quantify nutrient loads and provide overall direction to set the broad focus of management. Index models can then be used to refine on-the-ground investigations and investment priorities. In this way semi-distributed models can be combined with index models to provide a set of powerful tools to influence management decisions and outcomes. Copyright © 2010 Elsevier Ltd. All rights reserved.

  2. Lumped convolution integral models revisited: on the meaningfulness of inter catchment comparisons

    Directory of Open Access Journals (Sweden)

    S. Seeger

    2014-06-01

    Full Text Available The transit time distribution of a catchment is linked to the water storage potential and affects the susceptibility of a catchment to pollution. However, this characteristic of a catchment is still problematic to determine within a catchment and to predict among catchments based on physiographic or geological properties. In this study, lumped response and transit time convolution models coupled with a distributed physically based snow model were applied to simulate the stable water isotope compositions in stream discharge measured fortnightly in 24 meso-scale catchments in Switzerland. Three different types of transfer function (exponential, gamma distribution and two parallel linear reservoirs in two different implementation variants (strictly mathematical and normalised were optimised and compared. The derived mean transit times varied widely for one and the same catchment depending on the chosen transfer function, even when the model simulations led to very similar predictions of the tracer signal. Upon closer inspection of the transit time distributions, it appeared that two transfer functions mainly have to agree on an intermediate time scale around three months to reach similarly good prediction results in respect to fortnightly discharge samples, while their short-term and long-term behaviour seem to be of minor importance for the evaluation of the models. A couple of topographic indices showed significant correlations with the derived mean transit times. However, the collinearity of those indices, which were also correlated to mean annual precipitation sums, and the differing results among the different transfer functions, did not allow for the clear identification of one predictive topographical index. As a by-product of this study, a spatial interpolation method for monthly isotope concentrations in precipitation with modest input data requirement was developed and tested.

  3. Modelling catchment areas for secondary care providers: a case study.

    Science.gov (United States)

    Jones, Simon; Wardlaw, Jessica; Crouch, Susan; Carolan, Michelle

    2011-09-01

    Hospitals need to understand patient flows in an increasingly competitive health economy. New initiatives like Patient Choice and the Darzi Review further increase this demand. Essential to understanding patient flows are demographic and geographic profiles of health care service providers, known as 'catchment areas' and 'catchment populations'. This information helps Primary Care Trusts (PCTs) to review how their populations are accessing services, measure inequalities and commission services; likewise it assists Secondary Care Providers (SCPs) to measure and assess potential gains in market share, redesign services, evaluate admission thresholds and plan financial budgets. Unlike PCTs, SCPs do not operate within fixed geographic boundaries. Traditionally, SCPs have used administrative boundaries or arbitrary drive times to model catchment areas. Neither approach satisfactorily represents current patient flows. Furthermore, these techniques are time-consuming and can be challenging for healthcare managers to exploit. This paper presents three different approaches to define catchment areas, each more detailed than the previous method. The first approach 'First Past the Post' defines catchment areas by allocating a dominant SCP to each Census Output Area (OA). The SCP with the highest proportion of activity within each OA is considered the dominant SCP. The second approach 'Proportional Flow' allocates activity proportionally to each OA. This approach allows for cross-boundary flows to be captured in a catchment area. The third and final approach uses a gravity model to define a catchment area, which incorporates drive or travel time into the analysis. Comparing approaches helps healthcare providers to understand whether using more traditional and simplistic approaches to define catchment areas and populations achieves the same or similar results as complex mathematical modelling. This paper has demonstrated, using a case study of Manchester, that when estimating

  4. Hydroclimatic influences on non-stationary transit time distributions in a boreal headwater catchment

    Science.gov (United States)

    Peralta-Tapia, A.; Soulsby, C.; Tetzlaff, D.; Sponseller, R.; Bishop, K.; Laudon, H.

    2016-12-01

    Understanding how water moves through catchments - from the time it enters as precipitation to when it exits via streamflow - is of fundamental importance to understanding hydrological and biogeochemical processes. A basic descriptor of this routing is the Transit Time Distribution (TTD) which is derived from the input-output behavior of conservative tracers, the mean of which represents the average time elapsed between water molecules entering and exiting a flow system. In recent decades, many transit time studies have been conducted, but few of these have focused on snow-dominated catchments. We assembled a 10-year time series of isotopic data (δ18O and δ2H) for precipitation and stream water to estimate the characteristics of the transit time distribution in a boreal catchment in northern Sweden. We applied lumped parameter models using a gamma distribution to calculate the Mean Transit Time (MTT) of water over the entire period of record and to evaluate how inter-annual differences in transit times relate to hydroclimatic variability. The best fit MTT for the complete 10-year period was 650 days (Nash-Sutcliff Efficiency = 0.65), while the best fit inter-annual MTT ranged from 300 days up to 1200 days. Whilst there was a weak negative correlation between mean annual total precipitation and the annual MTT, this relationship was stronger (r2 = 0.53, p = 0.02) for the annual rain water input. This strong connection between the MTT and annual rainfall, rather than snowmelt, has strong implications for understanding future hydrological and biogeochemical processes in boreal regions, given that predicted warmer winters would translate into a greater proportion of precipitation falling as rain and thus shorter MTT in catchments. Such a change could have direct implications for the export of solutes and pollutants.

  5. Analysis of catchment behavior using residence time distributions with application to the Thuringian Basin

    Science.gov (United States)

    Prykhodko, Vladyslav; Heße, Falk; Kumar, Rohini; Samaniego, Luis; Attinger, Sabine

    2014-05-01

    Residence time distribution (RTD), as presented e.g. by Botter et al., are a novel mathematical framework for a quantitative characterization of hydrological systems. These distributions contain information about water storage, flow pathways and water sources and therefore improve the classical hydrograph methods by allowing both nonlinear as well as time-dependent dynamics. In our study we extend this previous works by applying this theoretical framework on real-world heterogeneous catchments. To that end we use a catchment-scale hydrological model (mHM) and apply the approach of Botter et al. to each spatial grid cell of mHM. To facilitate the coupling we amended Botter's approach by introducing additional fluxes (like runoff from unsaturated zone) and specifying the structure of the groundwater zone. By virtue of this coupling we could then make use of the realistic hydrological fluxes and state variables as provided by mHM. This allowed us to use both observed (precipitation, temperature, soil type etc.) and modeled data sets and asses their impact on the behavior of the resulting RTD's. We extended the aforementioned framework to analyze large catchments by including geomorphic effect due to the actual arrangement of subcatchments around the channel network using the flood routing algorithm of mHM. Additionally we study dependencies of the stochastic characteristics of RTD's on the meteorological and hydrological processes as well as on the morphological structure of the catchment. As a result we gained mean residence times (MRT) of base flow and groundwater flow on the mesoscale (4km x 4km). We compare the spatial distribution of MRT's with land cover and soil moisture maps as well as driving forces like precipitation and temperature. Results showed that land cover is a major predictor for MRT's whereas its impact on the mean evapotranspiration time was much lower. Additionally we determined the temporal evolution of mean travel times by using time series of

  6. How old is streamwater? Open questions in catchment transit time conceptualization, modeling and analysis

    Science.gov (United States)

    J.J. McDonnell; K. McGuire; P. Aggarwal; K.J. Beven; D. Biondi; G. Destouni; S. Dunn; A. James; J. Kirchner; P. Kraft; S. Lyon; P. Maloszewski; B. Newman; L. Pfister; A. Rinaldo; A. Rodhe; T. Sayama; J. Seibert; K. Solomon; C. Soulsby; M. Stewart; D. Tetzlaff; C. Tobin; P. Troch; M. Weiler; A. Western; A. Wörman; S. Wrede

    2010-01-01

    The time water spends travelling subsurface through a catchment to the stream network (i.e. the catchment water transit time) fundamentally describes the storage, flow pathway heterogeneity and sources of water in a catchment. The distribution of transit times reflects how catchments retain and release water and solutes that in turn set biogeochemical conditions and...

  7. Demonstrating the value of community-based ('citizen science') observations for catchment modelling and characterisation

    Science.gov (United States)

    Starkey, Eleanor; Parkin, Geoff; Birkinshaw, Stephen; Large, Andy; Quinn, Paul; Gibson, Ceri

    2017-05-01

    Despite there being well-established meteorological and hydrometric monitoring networks in the UK, many smaller catchments remain ungauged. This leaves a challenge for characterisation, modelling, forecasting and management activities. Here we demonstrate the value of community-based ('citizen science') observations for modelling and understanding catchment response as a contribution to catchment science. The scheme implemented within the 42 km2 Haltwhistle Burn catchment, a tributary of the River Tyne in northeast England, has harvested and used quantitative and qualitative observations from the public in a novel way to effectively capture spatial and temporal river response. Community-based rainfall, river level and flood observations have been successfully collected and quality-checked, and used to build and run a physically-based, spatially-distributed catchment model, SHETRAN. Model performance using different combinations of observations is tested against traditionally-derived hydrographs. Our results show how the local network of community-based observations alongside traditional sources of hydro-information supports characterisation of catchment response more accurately than using traditional observations alone over both spatial and temporal scales. We demonstrate that these community-derived datasets are most valuable during local flash flood events, particularly towards peak discharge. This information is often missed or poorly represented by ground-based gauges, or significantly underestimated by rainfall radar, as this study clearly demonstrates. While community-based observations are less valuable during prolonged and widespread floods, or over longer hydrological periods of interest, they can still ground-truth existing traditional sources of catchment data to increase confidence during characterisation and management activities. Involvement of the public in data collection activities also encourages wider community engagement, and provides important

  8. Advancing Land-Sea Conservation Planning: Integrating Modelling of Catchments, Land-Use Change, and River Plumes to Prioritise Catchment Management and Protection.

    Science.gov (United States)

    Álvarez-Romero, Jorge G; Pressey, Robert L; Ban, Natalie C; Brodie, Jon

    2015-01-01

    Human-induced changes to river loads of nutrients and sediments pose a significant threat to marine ecosystems. Ongoing land-use change can further increase these loads, and amplify the impacts of land-based threats on vulnerable marine ecosystems. Consequently, there is a need to assess these threats and prioritise actions to mitigate their impacts. A key question regarding prioritisation is whether actions in catchments to maintain coastal-marine water quality can be spatially congruent with actions for other management objectives, such as conserving terrestrial biodiversity. In selected catchments draining into the Gulf of California, Mexico, we employed Land Change Modeller to assess the vulnerability of areas with native vegetation to conversion into crops, pasture, and urban areas. We then used SedNet, a catchment modelling tool, to map the sources and estimate pollutant loads delivered to the Gulf by these catchments. Following these analyses, we used modelled river plumes to identify marine areas likely influenced by land-based pollutants. Finally, we prioritised areas for catchment management based on objectives for conservation of terrestrial biodiversity and objectives for water quality that recognised links between pollutant sources and affected marine areas. Our objectives for coastal-marine water quality were to reduce sediment and nutrient discharges from anthropic areas, and minimise future increases in coastal sedimentation and eutrophication. Our objectives for protection of terrestrial biodiversity covered species of vertebrates. We used Marxan, a conservation planning tool, to prioritise interventions and explore spatial differences in priorities for both objectives. Notable differences in the distributions of land values for terrestrial biodiversity and coastal-marine water quality indicated the likely need for trade-offs between catchment management objectives. However, there were priority areas that contributed to both sets of objectives. Our

  9. The sensitivity of catchment runoff models to rainfall data at different spatial scales

    Directory of Open Access Journals (Sweden)

    V. A. Bell

    2000-01-01

    Full Text Available The sensitivity of catchment runoff models to rainfall is investigated at a variety of spatial scales using data from a dense raingauge network and weather radar. These data form part of the HYREX (HYdrological Radar EXperiment dataset. They encompass records from 49 raingauges over the 135 km2 Brue catchment in south-west England together with 2 and 5 km grid-square radar data. Separate rainfall time-series for the radar and raingauge data are constructed on 2, 5 and 10 km grids, and as catchment average values, at a 15 minute time-step. The sensitivity of the catchment runoff models to these grid scales of input data is evaluated on selected convective and stratiform rainfall events. Each rainfall time-series is used to produce an ensemble of modelled hydrographs in order to investigate this sensitivity. The distributed model is shown to be sensitive to the locations of the raingauges within the catchment and hence to the spatial variability of rainfall over the catchment. Runoff sensitivity is strongest during convective rainfall when a broader spread of modelled hydrographs results, with twice the variability of that arising from stratiform rain. Sensitivity to rainfall data and model resolution is explored and, surprisingly, best performance is obtained using a lower resolution of rainfall data and model. Results from the distributed catchment model, the Simple Grid Model, are compared with those obtained from a lumped model, the PDM. Performance from the distributed model is found to be only marginally better during stratiform rain (R2 of 0.922 compared to 0.911 but significantly better during convective rain (R2 of 0.953 compared to 0.909. The improved performance from the distributed model can, in part, be accredited to the excellence of the dense raingauge network which would not be the norm for operational flood warning systems. In the final part of the paper, the effect of rainfall resolution on the performance of the 2 km distributed

  10. Modelling a river catchment using an electrical circuit analogue

    Directory of Open Access Journals (Sweden)

    C. G. Collier

    1998-01-01

    Full Text Available An electrical circuit analogue of a river catchment is described from which is derived an hydrological model of river flow called the River Electrical Water Analogue Research and Development (REWARD model. The model is based upon an analytic solution to the equation governing the flow of electricity in an inductance-capacitance-resistance (LCR circuit. An interpretation of L, C and R in terms of catchment parameters and physical processes is proposed, and tested for the River Irwell catchment in northwest England. Hydrograph characteristics evaluated using the model are compared with observed hydrographs, confirming that the modelling approach does provide a reliable framework within which to investigate the impact of variations in model input data.

  11. Technical Note: Automatic river network generation for a physically-based river catchment model

    Directory of Open Access Journals (Sweden)

    S. J. Birkinshaw

    2010-09-01

    Full Text Available SHETRAN is a physically-based distributed modelling system that gives detailed simulations in time and space of water flow and sediment and solute transport in river catchments. Standard algorithms for the automatic generation of river channel networks from digital elevation data are impossible to apply in SHETRAN and other similar models because the river channels are assumed to run along the edges of grid cells. In this work a new algorithm for the automatic generation of a river channel network in SHETRAN is described and its use in an example catchment demonstrated.

  12. Technical Note: Automatic river network generation for a physically-based river catchment model

    Science.gov (United States)

    Birkinshaw, S. J.

    2010-09-01

    SHETRAN is a physically-based distributed modelling system that gives detailed simulations in time and space of water flow and sediment and solute transport in river catchments. Standard algorithms for the automatic generation of river channel networks from digital elevation data are impossible to apply in SHETRAN and other similar models because the river channels are assumed to run along the edges of grid cells. In this work a new algorithm for the automatic generation of a river channel network in SHETRAN is described and its use in an example catchment demonstrated.

  13. Technical Note: Automatic river network generation for a physically-based river catchment model

    Directory of Open Access Journals (Sweden)

    S. J. Birkinshaw

    2010-05-01

    Full Text Available SHETRAN is a physically-based distributed modelling system that gives detailed simulations in time and space of water flow and sediment and solute transport in river catchments. Standard algorithms for the automatic generation of river channel networks from digital elevation data are impossible to apply in SHETRAN and other similar models because the river channels are assumed to run along the edges of grid cells. In this work a new algorithm for the automatic generation of a river channel network in SHETRAN is described and its use in an example catchment demonstrated.

  14. Assimilation of SMOS soil moisture into a distributed hydrological model and impacts on the water cycle variables over the Ouémé catchment in Benin

    Science.gov (United States)

    Leroux, Delphine J.; Pellarin, Thierry; Vischel, Théo; Cohard, Jean-Martial; Gascon, Tania; Gibon, François; Mialon, Arnaud; Galle, Sylvie; Peugeot, Christophe; Seguis, Luc

    2016-07-01

    Precipitation forcing is usually the main source of uncertainty in hydrology. It is of crucial importance to use accurate forcing in order to obtain a good distribution of the water throughout the basin. For real-time applications, satellite observations allow quasi-real-time precipitation monitoring like the products PERSIANN (Precipitation Estimation from Remotely Sensed Information using Artificial Neural Networks, TRMM (Tropical Rainfall Measuring Mission) or CMORPH (CPC (Climate Prediction Center) MORPHing). However, especially in West Africa, these precipitation satellite products are highly inaccurate and the water amount can vary by a factor of 2. A post-adjusted version of these products exists but is available with a 2 to 3 month delay, which is not suitable for real-time hydrologic applications. The purpose of this work is to show the possible synergy between quasi-real-time satellite precipitation and soil moisture by assimilating the latter into a hydrological model. Soil Moisture Ocean Salinity (SMOS) soil moisture is assimilated into the Distributed Hydrology Soil Vegetation Model (DHSVM) model. By adjusting the soil water content, water table depth and streamflow simulations are much improved compared to real-time precipitation without assimilation: soil moisture bias is decreased even at deeper soil layers, correlation of the water table depth is improved from 0.09-0.70 to 0.82-0.87, and the Nash coefficients of the streamflow go from negative to positive. Overall, the statistics tend to get closer to those from the reanalyzed precipitation. Soil moisture assimilation represents a fair alternative to reanalyzed rainfall products, which can take several months before being available, which could lead to a better management of available water resources and extreme events.

  15. AN APPROACH TO THE MODEL USE FOR MEASURING SUSPENDED SEDIMENT YIELD IN UNGAUGED CATCHMENTS

    Directory of Open Access Journals (Sweden)

    Sokchhay Heng

    2013-01-01

    Full Text Available Different types of water resources studies require the information of Suspended Sediment Yield (SSY in different time resolutions. In ungauged watersheds where hydrometeorogical time series are not available, the mean annual SSY (SSYa is solely predictable and catchment area is traditionally used as the predictor because it is the most important variable and generally determined during project planning. Firstly, this research tried to advance the traditional SSYa model by additionally associating global topographic data. Based on the jack-knife procedure, the modified method considering catchment area with slope greater than 15% was evaluated in 17 gauged catchments in the Lower Mekong Basin and the overall predictive accuracy was improved about 66% in term of mean absolute percentage error. Secondly, the predicted SSYa in each modeled catchment was monthly distributed using Unit mean annual Sedimentograph (USGa. The double-average USGa superior to the single-average one provides overall better quality results than the regionalized USGa dependent upon the spatial proximity approach. The model performance measured by Nash-Sutcliffe Efficiency (NSE is about 0.66 in median value and satisfactory results (NSE >0.50 are obtained in 11 catchments. Lastly, the validated regional model was regarded as a potential and feasible tool in solving sediment-ungauged issues in the basin.

  16. Predicting aquifer response time for application in catchment modeling.

    Science.gov (United States)

    Walker, Glen R; Gilfedder, Mat; Dawes, Warrick R; Rassam, David W

    2015-01-01

    It is well established that changes in catchment land use can lead to significant impacts on water resources. Where land-use changes increase evapotranspiration there is a resultant decrease in groundwater recharge, which in turn decreases groundwater discharge to streams. The response time of changes in groundwater discharge to a change in recharge is a key aspect of predicting impacts of land-use change on catchment water yield. Predicting these impacts across the large catchments relevant to water resource planning can require the estimation of groundwater response times from hundreds of aquifers. At this scale, detailed site-specific measured data are often absent, and available spatial data are limited. While numerical models can be applied, there is little advantage if there are no detailed data to parameterize them. Simple analytical methods are useful in this situation, as they allow the variability in groundwater response to be incorporated into catchment hydrological models, with minimal modeling overhead. This paper describes an analytical model which has been developed to capture some of the features of real, sloping aquifer systems. The derived groundwater response timescale can be used to parameterize a groundwater discharge function, allowing groundwater response to be predicted in relation to different broad catchment characteristics at a level of complexity which matches the available data. The results from the analytical model are compared to published field data and numerical model results, and provide an approach with broad application to inform water resource planning in other large, data-scarce catchments. © 2014, CommonWealth of Australia. Groundwater © 2014, National Ground Water Association.

  17. Catchment-Scale Simulation of Nitrogen Dynamics Using a Modular Hydrological Modelling Framework

    Science.gov (United States)

    Basu, N. B.; Shafii, M.; Craig, J. R.; Schiff, S. L.; Van Cappellen, P.

    2016-12-01

    The hydrological modelling framework Raven is a modular and flexible modelling framework for semi-distributed simulation of watershed hydrology. Raven enables the incorporation of different hydrologic processes, the evaluation of model choices, and hypothesis testing about model structure. Raven also supports the simulation of solute transport in catchments and in the surface water network. We developed a coupled hydrological-biogeochemical model within Raven to simulate catchment-scale nitrate loss in the Grand River Watershed (GRW), the largest basin in Southern Ontario feeding into the Lake Erie. GRW is a snow-dominated catchment and has severe nitrate contamination issues (due to intensive agriculture and a dense tile drainage system), especially during the snowmelt events. We used several sets of hydrochemical data (including tiles data), combined with a unique flow partitioning approach to constrain flow pathways in the hydrology model, which is critical to the accurate representation of the sources and sinks in the biogeochemical model. A biogeochemical model was then coupled to the hydrologic model in Raven to simulate nitrogen processes and identify nitrate loss at a variety of spatio-temporal scales in GRW. The preliminary results obtained after applying the coupled model to a subbasin in GRW are promising and we are at the stage of upscaling the model to the entire watershed. Raven, as an open-source object-oriented software, is currently being used by watershed managers, and incorporating nutrients dynamics in the code makes it applicable to solving water quality problems at the catchment scale as well.

  18. Building an Open Source Framework for Integrated Catchment Modeling

    Science.gov (United States)

    Jagers, B.; Meijers, E.; Villars, M.

    2015-12-01

    In order to develop effective strategies and associated policies for environmental management, we need to understand the dynamics of the natural system as a whole and the human role therein. This understanding is gained by comparing our mental model of the world with observations from the field. However, to properly understand the system we should look at dynamics of water, sediments, water quality, and ecology throughout the whole system from catchment to coast both at the surface and in the subsurface. Numerical models are indispensable in helping us understand the interactions of the overall system, but we need to be able to update and adjust them to improve our understanding and test our hypotheses. To support researchers around the world with this challenging task we started a few years ago with the development of a new open source modeling environment DeltaShell that integrates distributed hydrological models with 1D, 2D, and 3D hydraulic models including generic components for the tracking of sediment, water quality, and ecological quantities throughout the hydrological cycle composed of the aforementioned components. The open source approach combined with a modular approach based on open standards, which allow for easy adjustment and expansion as demands and knowledge grow, provides an ideal starting point for addressing challenging integrated environmental questions.

  19. Parameterization of a Hydrological Model for a Large, Ungauged Urban Catchment

    Directory of Open Access Journals (Sweden)

    Gerald Krebs

    2016-10-01

    Full Text Available Urbanization leads to the replacement of natural areas by impervious surfaces and affects the catchment hydrological cycle with adverse environmental impacts. Low impact development tools (LID that mimic hydrological processes of natural areas have been developed and applied to mitigate these impacts. Hydrological simulations are one possibility to evaluate the LID performance but the associated small-scale processes require a highly spatially distributed and explicit modeling approach. However, detailed data for model development are often not available for large urban areas, hampering the model parameterization. In this paper we propose a methodology to parameterize a hydrological model to a large, ungauged urban area by maintaining at the same time a detailed surface discretization for direct parameter manipulation for LID simulation and a firm reliance on available data for model conceptualization. Catchment delineation was based on a high-resolution digital elevation model (DEM and model parameterization relied on a novel model regionalization approach. The impact of automated delineation and model regionalization on simulation results was evaluated for three monitored study catchments (5.87–12.59 ha. The simulated runoff peak was most sensitive to accurate catchment discretization and calibration, while both the runoff volume and the fit of the hydrograph were less affected.

  20. Exploring Hydrological Flow Paths in Conceptual Catchment Models using Variance-based Sensitivity Analysis

    Science.gov (United States)

    Mockler, E. M.; O'Loughlin, F.; Bruen, M. P.

    2013-12-01

    Conceptual rainfall runoff (CRR) models aim to capture the dominant hydrological processes in a catchment in order to predict the flows in a river. Most flood forecasting models focus on predicting total outflows from a catchment and often perform well without the correct distribution between individual pathways. However, modelling of water flow paths within a catchment, rather than its overall response, is specifically needed to investigate the physical and chemical transport of matter through the various elements of the hydrological cycle. Focus is increasingly turning to accurately quantifying the internal movement of water within these models to investigate if the simulated processes contributing to the total flows are realistic in the expectation of generating more robust models. Parameter regionalisation is required if such models are to be widely used, particularly in ungauged catchments. However, most regionalisation studies to date have typically consisted of calibrations and correlations of parameters with catchment characteristics, or some variations of this. In order for a priori parameter estimation in this manner to be possible, a model must be parametrically parsimonious while still capturing the dominant processes of the catchment. The presence of parameter interactions within most CRR model structures can make parameter prediction in ungauged basins very difficult, as the functional role of the parameter within the model may not be uniquely identifiable. We use a variance based sensitivity analysis method to investigate parameter sensitivities and interactions in the global parameter space of three CRR models, simulating a set of 30 Irish catchments within a variety of hydrological settings over a 16 year period. The exploration of sensitivities of internal flow path partitioning was a specific focus and correlations between catchment characteristics and parameter sensitivities were also investigated to assist in evaluating model performances

  1. Integrated catchment modelling in a Semi-arid area

    CSIR Research Space (South Africa)

    Bugan, Richard DH

    2010-09-01

    Full Text Available , will increasingly need water quality and quantity management tools to be able to make informed decisions. Integrated catchment modelling (ICM) is regarded as being a valuable tool for integrated water resource management. It enables officials and scientists to make...

  2. Discharge Water Quality Models of Storm Runoff in a Catchment

    Institute of Scientific and Technical Information of China (English)

    2002-01-01

    The relationships between the water qualities of nitrogen and phosphorous contents in the discharge water and the discharge of storm runoff of an experimental catchment including terraced paddy field are analyzed based on experiment results of the catchment. By summarizing the currently related research on water quality models, the water quality models of different components of storm runoff of the catchment are presented and verified with the experiment data of water quality analyses and the corresponding discharge of the storm runoffs during 3 storms. Through estimating the specific discharge of storm runoff, the specific load of different components of nitrogen and phosphorus in the discharge water of the catchment can be forecasted by the models. It is found that the mathematical methods of linear regression are very useful for analysis of the relationship between the concentrations of nitrogen and phosphorus and the water discharge of storm runoff. It is also found that the most content of the nitrogen (75%) in the discharge water is organic, while half of the content (49%) of phosphorus in the discharge water is inorganic.

  3. Optimization of precipitation inputs for SWAT modeling in mountainous catchment

    Science.gov (United States)

    Tuo, Ye; Chiogna, Gabriele; Disse, Markus

    2016-04-01

    Precipitation is often the most important input data in hydrological models when simulating streamflow in mountainous catchment. The Soil and Water Assessment Tool (SWAT), a widely used hydrological model, only makes use of data from one precipitation gauging station which is nearest to the centroid of each subcatchment, eventually corrected using the band elevation method. This leads in general to inaccurate subcatchment precipitation representation, which results in unreliable simulation results in mountainous catchment. To investigate the impact of the precipitation inputs and consider the high spatial and temporal variability of precipitation, we first interpolated 21 years (1990-2010) of daily measured data using the Inverse Distance Weighting (IDW) method. Averaged IDW daily values have been calculated at the subcatchment scale to be further supplied as optimized precipitation inputs for SWAT. Both datasets (Measured data and IDW data) are applied to three Alpine subcatchments of the Adige catchment (North-eastern Italy, 12100 km2) as precipitation inputs. Based on the calibration and validation results, model performances are evaluated according to the Nash Sutchliffe Efficiency (NSE) and Coefficient of Determination (R2). For all three subcatchments, the simulation results with IDW inputs are better than the original method which uses measured inputs from the nearest station. This suggests that IDW method could improve the model performance in Alpine catchments to some extent. By taking into account and weighting the distance between precipitation records, IDW supplies more accurate precipitation inputs for each individual Alpine subcatchment, which would as a whole lead to an improved description of the hydrological behavior of the entire Adige catchment.

  4. Technical Note: Automatic river network generation for a physically-based river catchment model

    OpenAIRE

    2010-01-01

    SHETRAN is a physically-based distributed modelling system that gives detailed simulations in time and space of water flow and sediment and solute transport in river catchments. Standard algorithms for the automatic generation of river channel networks from digital elevation data are impossible to apply in SHETRAN and other similar models because the river channels are assumed to run along the edges of grid cells. In this work a new algorithm for the automatic generation of a river cha...

  5. Technical Note: Automatic river network generation for a physically-based river catchment model

    OpenAIRE

    2010-01-01

    SHETRAN is a physically-based distributed modelling system that gives detailed simulations in time and space of water flow and sediment and solute transport in river catchments. Standard algorithms for the automatic generation of river channel networks from digital elevation data are impossible to apply in SHETRAN and other similar models because the river channels are assumed to run along the edges of grid cells. In this work a new algorithm for the automatic generation of a river channel ne...

  6. Spatial Distribution of Surface Soil Moisture in a Small Forested Catchment

    Science.gov (United States)

    Predicting the spatial distribution of soil moisture is an important hydrological question. We measured the spatial distribution of surface soil moisture (upper 6 cm) using an Amplitude Domain Reflectometry sensor at the plot scale (2 × 2 m) and small catchment scale (0.84 ha) in...

  7. Spatial Distribution of Surface Soil Moisture in a Small Forested Catchment

    Science.gov (United States)

    Predicting the spatial distribution of soil moisture is an important hydrological question. We measured the spatial distribution of surface soil moisture (upper 6 cm) using an Amplitude Domain Reflectometry sensor at the plot scale (2 × 2 m) and small catchment scale (0.84 ha) in...

  8. Development and evaluation of the Soil and Water Temperature Model (SWTM) for rural catchments

    Science.gov (United States)

    Kwon, Yonghwan; Koo, Bhon K.

    2017-10-01

    A physically-based energy balance model, the Soil and Water Temperature Model (SWTM), is developed in an effort to improve the soil temperature estimation for Korean rural watersheds or catchments, which are characterized by heterogeneous land-cover types and rugged topography and have many paddy fields retaining surface water during the growing season. The developed model is applied to a small rural catchment in South Korea where soil temperature is measured for two months, July to August 2008, at eight monitoring sites including forest, paddy field, dry field, and natural vegetation area. The degree of agreement between the simulated and observed soil temperature is quite good for the soil surface (RMSE 1.11-3.16 °C, R2 0.80-0.88), except for forests. Although some estimation errors resulting from data deficiency and model structure are observed, SWTM reasonably well simulates the spatial and temporal distribution of soil temperature at the catchment scale by considering the effects of topography, vegetation cover, and hydrological characteristics, especially the existence of surface water. SWTM is well suited for rural watersheds or catchments and expected to contribute to enhancing our understanding of watershed biogeochemical processes and managing the watershed environment.

  9. A look inside 'black box' hydrograph separation models: A study at the hydrohill catchment

    Science.gov (United States)

    Kendall, C.; McDonnell, Jeffery J.; Gu, W.

    2001-01-01

    Runoff sources and dominant flowpaths are still poorly understood in most catchments; consequently, most hydrograph separations are essentially 'black box' models where only external information is used. The well-instrumented 490 m2 Hydrohill artificial grassland catchment located near Nanjing (China) was used to examine internal catchment processes. Since groundwater levels never reach the soil surface at this site, two physically distinct flowpaths can unambiguously be defined: surface and subsurface runoff. This study combines hydrometric, isotopic and geochemical approaches to investigating the relations between the chloride, silica, and oxygen isotopic compositions of subsurface waters and rainfall. During a 120 mm storm over a 24 h period in 1989, 55% of event water input infiltrated and added to soil water storage; the remainder ran off as infiltration-excess overland flow. Only about 3-5% of the pre-event water was displaced out of the catchment by in-storm rainfall. About 80% of the total flow was quickflow, and 10% of the total flow was pre-event water, mostly derived from saturated flow from deeper soils. Rain water with high ??18O values from the beginning of the storm appeared to be preferentially stored in shallow soils. Groundwater at the end of the storm shows a wide range of isotopic and chemical compositions, primarily reflecting the heterogeneous distribution of the new and mixed pore waters. High chloride and silica concentrations in quickflow runoff derived from event water indicate that these species are not suitable conservative tracers of either water sources or flowpaths in this catchment. Determining the proportion of event water alone does not constrain the possible hydrologic mechanisms sufficiently to distinguish subsurface and surface flowpaths uniquely, even in this highly controlled artificial catchment. We reconcile these findings with a perceptual model of stormflow sources and flowpaths that explicitly accounts for water, isotopic

  10. a Study of Urban Stormwater Modeling Approach in Singapore Catchment

    Science.gov (United States)

    Liew, S. C.; Liong, S. Y.; Vu, M. T.

    2011-07-01

    Urbanization has the direct effect of increasing the amount of surface runoff to be discharged through man-made drainage systems. Thus, Singapore's rapid urbanization has drawn great attention on flooding issues. In view of this, proper stormwater modeling approach is necessary for the assessment planning, design, and control of the storm and combines sewerage system. Impacts of urbanization on surface runoff and catchment flooding in Singapore are studied in this paper. In this study, the application of SOBEK-urban 1D is introduced on model catchments and a hypothetical catchment model is created for simulation purpose. Stormwater modeling approach using SOBEK-urban offers a comprehensive modeling tool for simple or extensive urban drainage systems consisting of sewers and open channels despite its size and complexity of the network. The findings from the present study show that stormwater modeling is able to identify flood area and the impact of the anticipated sea level on urban drainage network. Consequently, the performance of the urban drainage system can be improved and early prevention approaches can be carried out.

  11. A conceptual glacio-hydrological model for high mountainous catchments

    Directory of Open Access Journals (Sweden)

    B. Schaefli

    2005-01-01

    Full Text Available In high mountainous catchments, the spatial precipitation and therefore the overall water balance is generally difficult to estimate. The present paper describes the structure and calibration of a semi-lumped conceptual glacio-hydrological model for the joint simulation of daily discharge and annual glacier mass balance that represents a better integrator of the water balance. The model has been developed for climate change impact studies and has therefore a parsimonious structure; it requires three input times series – precipitation, temperature and potential evapotranspiration – and has 7 parameters to calibrate. A multi-signal approach considering daily discharge and – if available – annual glacier mass balance has been developed for the calibration of these parameters. The model has been calibrated for three different catchments in the Swiss Alps having glaciation rates between 37% and 52%. It simulates well the observed daily discharge, the hydrological regime and some basic glaciological features, such as the annual mass balance.

  12. [Spatial distribution of aboveground biomass of shrubs in Tianlaochi catchment of the Qilian Mountains].

    Science.gov (United States)

    Liang, Bei; Di, Li; Zhao, Chuan-Yan; Peng, Shou-Zhang; Peng, Huan-Hua; Wang, Chao

    2014-02-01

    This study estimated the spatial distribution of the aboveground biomass of shrubs in the Tianlaochi catchment of Qilian Mountains based on the field survey and remote sensing data. A relationship model of the aboveground biomass and its feasibly measured factors (i. e. , canopy perimeter and plant height) was built. The land use was classified by object-oriented technique with the high resolution image (GeoEye-1) of the study area, and the distribution of shrub coverage was extracted. Then the total aboveground biomass of shrubs in the study area was estimated by the relationship model with the distribution of shrub coverage. The results showed that the aboveground biomass of shrubs in the study area was 1.8 x 10(3) t and the aboveground biomass per unit area was 1598.45 kg x m(-2). The distribution of shrubs mainly was at altitudes of 3000-3700 m, and the aboveground biomass of shrubs on the sunny slope (1.15 x 10(3) t) was higher than that on the shady slope (0.65 x 10(3) t).

  13. Spatial distribution of electrical conductivity and stable isotopes in groundwater in large catchments: a geostatistical approach in the Quequén Grande River catchment, Argentina.

    Science.gov (United States)

    Quiroz Londoño, Orlando Mauricio; Martínez, Daniel Emilio; Massone, Hector Enrique; Londoño Ciro, Libardo Antonio; Dapeña, Cristina

    2015-01-01

    Stable isotopes and electrical conductivity in groundwater were used as natural tracers to adjust the hydrogeological conceptual model in one of the largest catchments within the inter-mountainous Pampa plain, Argentina. Geostatistical tools were used to define the model that best fitted the spatial distribution of each tracer, and information was obtained in areas where there was a lack of data. The conventional isotopic analysis allowed the identification of three groundwater groups with different isotopic fingerprints. One group containing 56% of the total groundwater samples suggested a well-mixed system and soil infiltration precipitation as the main recharge source to the aquifer. The other two groups included samples with depleted (25.5%) and enriched (18.5%) isotopic compositions, respectively. The combination of δ(18)O, δ(2)H and electrical conductivities maps suggested ascending regional flows and water transfer from the Quequén Grande River catchment to the Moro creek. The spatial interpretation of these tracers modified the conceptual hydrogeological model of the Quequén Grande River.

  14. Topographical and Hydrological Influences on the Spatial Distribution of Mercury at the Catchment Scale

    Science.gov (United States)

    Gunda, T.; Converse, A.; Riscassi, A.; Scanlon, T. M.

    2009-12-01

    Inorganic forms of mercury (Hg) can be converted through natural processes into methylmercury, a highly potent neurotoxin that can bioaccumulate in food chains and pose a risk to human health. Although Hg can enter aquatic environments through direct deposition, the predominant source tends to be mobilized Hg deposited in nearby terrestrial systems. Therefore, understanding the complex intermediate Hg cycling in vegetation and soils is crucial to predicting its presence in water bodies and potential for bioaccumulation. While prior studies have revealed dependence of Hg distribution on forest types and soil characteristics, less attention has been given to the role of aspect and hydrological factors on Hg deposition and consequent spatial distribution within catchments. My research addresses this by conducting a litterfall and soil sampling study to assess Hg spatial distribution within two paired catchments: northwest-facing North Fork Dry Run and southeast-facing Hannah Run. Litterfall and soil samples collected through a random stratified sampling process were analyzed for total Hg concentrations using a Cold Vapor Atomic Fluorescence Spectrometry. An analysis of variance conducted on leaf litter and soil Hg concentrations revealed that: (1) Hg accumulation in soils was significantly greater in the northwest-facing catchment than in the south-east facing catchment, while Hg accumulation in leaves was not found to differ, and (2) within each catchment the likelihood of saturation was not found to play a significant role in governing Hg accumulation in soils. Higher Hg levels in the soils of North Forth Dry Run could be attributable to predominant wind direction from sources of Hg (i.e., coal-burning power plants). Within catchments, lack of appreciable Hg deposition resulted in statistically insignificant variation amongst topographic index classes. The results of this study reveal the potential implications of mountainous terrains in distributing Hg arising from

  15. Parsimonious catchment and river flow modelling

    NARCIS (Netherlands)

    Khatibi, R.H.; Moore, R.J.; Booij, Martijn J.; Cadman, D.; Boyce, G.; Rizzoli, A.E.; Jakeman, A.J.

    2002-01-01

    It is increasingly the case that models are being developed as “evolving” products rather than one-off application tools, such that auditable modelling versus ad hoc treatment of models becomes a pivotal issue. Auditable modelling is particularly vital to “parsimonious modelling” aimed at meeting

  16. Parameterization of a Hydrological Model for a Large, Ungauged Urban Catchment

    OpenAIRE

    Gerald Krebs; Teemu Kokkonen; Heikki Setälä; Harri Koivusalo

    2016-01-01

    Urbanization leads to the replacement of natural areas by impervious surfaces and affects the catchment hydrological cycle with adverse environmental impacts. Low impact development tools (LID) that mimic hydrological processes of natural areas have been developed and applied to mitigate these impacts. Hydrological simulations are one possibility to evaluate the LID performance but the associated small-scale processes require a highly spatially distributed and explicit modeling approach. Howe...

  17. Modeling the behavior of an ungauged catchment using alternative datasets: a case study of the Caribou catchment in Canada

    Science.gov (United States)

    Labrecque, Geneviève; Boucher, Marie-Amélie; Chesnaux, Romain

    2017-04-01

    The modelling of ungauged catchments is a long standing problem in hydrology and there is still no general consensus regarding the best practices to adopt in a variety of situations. In addition to flood and drought forecasting, there are other interests of modelling the hydrological behaviour of a catchment, whether it is gauged or not. For instance, estimation of groundwater recharge can be performed through an integrated modeling of the catchment. In this study, the WaSim model is used to model the hydrology of the Caribou River catchment located in the province of Quebec, in Canada. Since this catchment includes an important aquifer that is used both for drinking water, industrial and potential agricultural purposes, an accurate recharge assessment is important and is the long-term objective of the project. The WaSim model was chosen due to its very versatile soil sub-model features which allow to simulate subsurface flows and calculate the groundwater recharge as an output variable. Since the Caribou River is ungauged, alternative means of calibrating the free parameters of WaSim had to be implemented. The implementation of a calibration protocol that can get the most out of the few available data is a secondary objective and is the subject of this presentation. First, a « twin » gauged catchment is selected for its physiographic and hydro-climatic similarities with the Caribou River catchment. Streamflow series from this « twin » catchment are then transferred and used jointly with the dynamically dimensioned search (DDS) algorithm (Tolson and Shoemaker 2007) to obtain a raw calibration of the WaSim model parameters. This initial calibration can be further refined using two available datasets: (1) snow water equivalent data interpolated on a 10 km by 10 km grid and (2) a short and discontinuous time series of streamflow obtained using the land-surface scheme of the environmental multiscale atmospheric model (GEM) at Environment and Climate Change Canada

  18. Sediment yield model implementation based on check dam infill stratigraphy in a semiarid Mediterranean catchment

    Directory of Open Access Journals (Sweden)

    G. Bussi

    2013-08-01

    Full Text Available Soil loss and sediment transport in Mediterranean areas are driven by complex non-linear processes which have been only partially understood. Distributed models can be very helpful tools for understanding the catchment-scale phenomena which lead to soil erosion and sediment transport. In this study, a modelling approach is proposed to reproduce and evaluate erosion and sediment yield processes in a Mediterranean catchment (Rambla del Poyo, Valencia, Spain. Due to the lack of sediment transport records for model calibration and validation, a detailed description of the alluvial stratigraphy infilling a check dam that drains a 12.9 km2 sub-catchment was used as indirect information of sediment yield data. These dam infill sediments showed evidences of at least 15 depositional events (floods over the time period 1990–2009. The TETIS model, a distributed conceptual hydrological and sediment model, was coupled to the Sediment Trap Efficiency for Small Ponds (STEP model for reproducing reservoir retention, and it was calibrated and validated using the sedimentation volume estimated for the depositional units associated with discrete runoff events. The results show relatively low net erosion rates compared to other Mediterranean catchments (0.136 Mg ha−1 yr−1, probably due to the extensive outcrops of limestone bedrock, thin soils and rather homogeneous vegetation cover. The simulated sediment production and transport rates offer model satisfactory results, further supported by in-site palaeohydrological evidences and spatial validation using additional check dams, showing the great potential of the presented data assimilation methodology for the quantitative analysis of sediment dynamics in ungauged Mediterranean basins.

  19. Modelling the initial structure dynamics of soil and sediment exemplified for a constructed hydrological catchment

    Science.gov (United States)

    Maurer, Thomas; Schneider, Anna; Gerke, Horst H.

    2016-04-01

    The structure of a hydrological catchment is determined by the geometry of the boundaries and the spatial distribution of soil and sediment properties. Models of the 3D subsurface structure and the soil heterogeneity have often been built based on geostatistical approaches and conditional simulations for spatial interpolation between measurements. Here, an alternative model was proposed that generated 3D subsurface structures by imitating basic structures resulting from mass distribution processes. Instead of directly assuming stochastic variations of the subsurface structure, the present approach assumed stochastic variations in parameters of the process-based algorithms of the generator models. The constructed hydrological catchment "Hühnerwasser" located in the Lower Lusatia region of Brandenburg, Germany, was used as an example for the development of such a 3D structure generator model. Boundary geometries and changes in the surface topography due to erosion and sedimentation processes were quantified on the basis of digital elevation models (DEMs) derived from aerial photographs and terrestrial laser scanning information. Basic sediment properties came i) from a geological model of the parent material at the outcrop site, ii) from actual soil sample measurements on-site, and iii) based on stochastic texture variations. Sediment distributions were generated according to construction processes such as sediment dumping, particle segregation, and soil compaction. The resulting internal structures reflect the formation of spoil cones and surface compaction by machinery. The simulated 3D model scenarios of soil texture and bulk density distributions were incorporated in a gridded 3D volume model using the 3D software tool GoCAD (Paradigm Ltd.). This 3D distributed solid phase structure of the catchment allowed for a more direct comparison with observations using minimal invasive methods. By including structural changes over time (e.g., derived from DEM

  20. Modelling the impact of forest loss on shallow landslide sediment yield, Ijuez river catchment, Spanish Pyrenees

    Directory of Open Access Journals (Sweden)

    2007-01-01

    Full Text Available The SHETRAN model for simulating the sediment yield arising from shallow landslides at the scale of a river catchment was applied to the 45-km2 Ijuez catchment in the central Spanish Pyrenees, to investigate the effect of loss of forest cover on landslide and debris flow incidence and on catchment sediment yield. The application demonstrated how such a model, with a large number of parameters to be evaluated, can be used even when directly measured data are not available: rainfall and discharge time series were generated by reference to other local records and data providing the basis for a soil map were obtained by a short field campaign. Uncertainty bounds for the outputs were determined as a function of the uncertainty in the values of key model parameters. For a four-year period and for the existing forested state of the catchment, a good ability to simulate the observed long term spatial distribution of debris flows (represented by a 45-year inventory and to determine catchment sediment yield within the range of regional observations was demonstrated. The lower uncertainty bound on simulated landslide occurrence approximated the observed annual rate of landsliding and suggests that landslides provide a relatively minor proportion of the total sediment yield, at least in drier years. A scenario simulation in which the forest cover was replaced by grassland indicated an increase in landsliding but a decrease in the number of landslides which evolve into debris flows and, at least for drier years, a reduction in sediment delivery to the channel network.

  1. Tradeoffs for the implementation of a process-based catchment model in a poorly gauged, highly glacierized Himalayan headwater

    Directory of Open Access Journals (Sweden)

    M. Konz

    2006-11-01

    Full Text Available The paper presents a catchment modeling approach for remote glacierized Himalayan catchments. The distributed catchment model TACD, which is widely based on the HBV model, was further developed for the application in highly glacierized catchments on a daily timestep and applied to the Nepalese Himalayan headwater Langtang Khola (360 km2. Low laying reference stations are taken for temperature extrapolation applying a second order polynomial function. Probability based statistical methods enable bridging data gaps in daily precipitation time series and the redistribution of cumulated precipitation sums over the previous days. Snow and ice melt was calculated in a distributed way based on the temperature-index method employing calculated daily potential sunshine durations. Different melting conditions of snow and ice and melting of ice under debris layers were considered. The spatial delineation of hydrological response units was achieved by taking topographic and physiographic information from maps and satellite images into account, and enabled to incorporate process knowledge into the model. Simulation results demonstrated that the model is able to simulate daily discharge for a period of 10 years and point glacier mass balances observed in the research area with an adequate reliability. The simple but robust data pre-processing and modeling approach enables the determination of the components of the water balance of a remote, data scarce catchment with a minimum of input data.

  2. Field scale heterogeneity of redox conditions in till-upscaling to a catchment nitrate model

    DEFF Research Database (Denmark)

    Hansen, J.R.; Erntsen, V.; Refsgaard, J.C.

    2008-01-01

    Point scale studies in different settings of glacial geology show a large local variation of redox conditions. There is a need to develop an upscaling methodology for catchment scale models. This paper describes a study of field-scale heterogeneity of redox-interfaces in a till aquitard within...... that the depth of the redox-interface is randomly distributed according to a log-normal probability distribution function. The upscaling approach using the random redox model estimated recharge concentrations comparable to the observed concentration in the underlying aquifer. The presented upscaling approach...

  3. Spatial Modelling of Sediment Transport over the Upper Citarum Catchment

    Directory of Open Access Journals (Sweden)

    Poerbandono

    2006-05-01

    Full Text Available This paper discusses set up of a spatial model applied in Geographic Information System (GIS environment for predicting annual erosion rate and sediment yield of a watershed. The study area is situated in the Upper Citarum Catchment of West Java. Annual sediment yield is considered as product of erosion rate and sediment delivery ratio to be modelled under similar modeling tool. Sediment delivery ratio is estimated on the basis of sediment resident time. The modeling concept is based on the calculation of water flow velocity through sub-catchment surface, which is controlled by topography, rainfall, soil characteristics and various types of land use. Relating velocity to known distance across digital elevation model, sediment resident time can be estimated. Data from relevance authorities are used. Bearing in mind limited knowledge of some governing factors due to lack of observation, the result has shown the potential of GIS for spatially modeling regional sediment transport. Validation of model result is carried out by evaluating measured and computed total sediment yield at the main outlet. Computed total sediment yields for 1994 and 2001 are found to be 1.96×106 and 2.10×106tons/year. They deviate roughly 54 and 8% with respect to those measured in the field. Model response due to land use change observed in 2001 and 1994 is also recognised. Under presumably constant rainfall depth, an increase of overall average annual erosion rate of 11% resulted in an increase of overall average sediment yield of 7%.

  4. Predicting nitrate discharge dynamics in mesoscale catchments using the lumped StreamGEM model and Bayesian parameter inference

    Science.gov (United States)

    Woodward, Simon James Roy; Wöhling, Thomas; Rode, Michael; Stenger, Roland

    2017-09-01

    The common practice of infrequent (e.g., monthly) stream water quality sampling for state of the environment monitoring may, when combined with high resolution stream flow data, provide sufficient information to accurately characterise the dominant nutrient transfer pathways and predict annual catchment yields. In the proposed approach, we use the spatially lumped catchment model StreamGEM to predict daily stream flow and nitrate concentration (mg L-1 NO3-N) in four contrasting mesoscale headwater catchments based on four years of daily rainfall, potential evapotranspiration, and stream flow measurements, and monthly or daily nitrate concentrations. Posterior model parameter distributions were estimated using the Markov Chain Monte Carlo sampling code DREAMZS and a log-likelihood function assuming heteroscedastic, t-distributed residuals. Despite high uncertainty in some model parameters, the flow and nitrate calibration data was well reproduced across all catchments (Nash-Sutcliffe efficiency against Log transformed data, NSL, in the range 0.62-0.83 for daily flow and 0.17-0.88 for nitrate concentration). The slight increase in the size of the residuals for a separate validation period was considered acceptable (NSL in the range 0.60-0.89 for daily flow and 0.10-0.74 for nitrate concentration, excluding one data set with limited validation data). Proportions of flow and nitrate discharge attributed to near-surface, fast seasonal groundwater and slow deeper groundwater were consistent with expectations based on catchment geology. The results for the Weida Stream in Thuringia, Germany, using monthly as opposed to daily nitrate data were, for all intents and purposes, identical, suggesting that four years of monthly nitrate sampling provides sufficient information for calibration of the StreamGEM model and prediction of catchment dynamics. This study highlights the remarkable effectiveness of process based, spatially lumped modelling with commonly available monthly

  5. Should we trust build-up/wash-off water quality models at the scale of urban catchments?

    Science.gov (United States)

    Bonhomme, Céline; Petrucci, Guido

    2017-01-01

    Models of runoff water quality at the scale of an urban catchment usually rely on build-up/wash-off formulations obtained through small-scale experiments. Often, the physical interpretation of the model parameters, valid at the small-scale, is transposed to large-scale applications. Testing different levels of spatial variability, the parameter distributions of a water quality model are obtained in this paper through a Monte Carlo Markov Chain algorithm and analyzed. The simulated variable is the total suspended solid concentration at the outlet of a periurban catchment in the Paris region (2.3 km(2)), for which high-frequency turbidity measurements are available. This application suggests that build-up/wash-off models applied at the catchment-scale do not maintain their physical meaning, but should be considered as "black-box" models. Copyright © 2016 Elsevier Ltd. All rights reserved.

  6. Measurement of rainfall distribution on a small catchment for the evaluation of canopy interception effects

    Science.gov (United States)

    Maurer, Thomas; Schapp, Andrea; Büchner, Steffen; Menzel, Hannes; Hinz, Christoph

    2014-05-01

    Variability of rainfall and throughfall is an essential characteristic of the water balance at spatial scales ranging from meters to hundreds of meters or even kilometers. The amount of throughfall is governed by the characteristics of the vegetation canopy and the involved interception and stemflow effects. In initial, developing ecosystems, distinct patterns of the growing vegetation (e.g. patchiness) supposedly govern the spatial distribution of water in the system, thereby initiating and supporting hydro-ecological feedback processes. Questions are i) is the spatial variability of vegetation relevant for the system as a whole, and ii) how does the distribution of the effective precipitation (i.e. the infiltration) change over time in dependency of vegetation succession? We present the first results of a spatially distributed measurement approach of surface-near precipitation on the constructed catchment "Hühnerwasser" ("Chicken Creek"). The 6-ha site is located in the recultivation area of the lignite open-cast mine "Welzow-Süd" in Lower Lusatia, Brandenburg, Germany. Here, the free development of an initial ecosystem is investigated since September 2005. After eight years of succession, the spatial distribution of plant species is highly heterogeneous, and gains increasing influence on throughfall patterns, thus impacting the distribution of soil humidity and possibly even surface runoff. For spatially distributed precipitation measurement, 47 tipping bucket rain gauges were installed in heights of 0.5 m and 1.0 m along two transects on the catchment. Rain gauge data were collected by a wireless sensor node network provided by the Sens4U joint research project. The transects run NW-SE and NE-SW and cover the range of plant communities presently existing in the ecosystem: locust copses, dense sallow thorn bushes and reeds, base herbaceous and medium-rise small-reed vegetation, and open areas covered by moss and lichens. The raw measurement data were

  7. Distribution and diversity of fungi in freshwater sediments on a river catchment scale.

    Science.gov (United States)

    Liu, Jie; Wang, Jianan; Gao, Guanghai; Bartlam, Mark G; Wang, Yingying

    2015-01-01

    Fungal communities perform essential functions in biogeochemical cycles. However, knowledge of fungal community structural changes in river ecosystems is still very limited. In the present study, we combined culture-dependent and culture-independent methods to investigate fungal distribution and diversity in sediment on a regional scale in the Songhua River catchment, located in North-East Asia. A total of 147 samples over the whole river catchment were analyzed. The results showed that compared to the mainstream, the tributaries have a higher fungal community organization and culturable fungal concentration, but possess lower community dynamics as assessed by denaturing gradient gel electrophoresis (DGGE). Furthermore, phylogenetic analysis of DGGE bands showed that Ascomycota and Basidiomycota were the predominant community in the Songhua River catchment. Redundancy analysis revealed that longitude was the primary factor determining the variation of fungal community structure, and fungal biomass was mainly related to the total nutrient content. Our findings provide new insights into the characteristics of fungal community distribution in a temperate zone river at a regional scale, and demonstrate that fungal dispersal is restricted by geographical barriers in a whole river catchment.

  8. Optimization of a catchment-scale coupled surface-subsurface hydrological model using pilot points

    Science.gov (United States)

    Danapour, Mehrdis; Stisen, Simon; Lajer Højberg, Anker

    2016-04-01

    Transient coupled surface-subsurface models are usually complex and contain a large amount of spatio-temporal information. In the traditional calibration approach, model parameters are adjusted against only few spatially aggregated observations of discharge or individual point observations of groundwater head. However, this approach doesn't enable an assessment of spatially explicit predictive model capabilities at the intermediate scale relevant for many applications. The overall objectives of this project is to develop a new model calibration and evaluation framework by combining distributed model parameterization and regularization with new types of objective functions focusing on optimizing spatial patterns rather than individual points or catchment scale features. Inclusion of detailed observed spatial patterns of hydraulic head gradients or relevant information obtained from remote sensing data in the calibration process could allow for a better representation of spatial variability of hydraulic properties. Pilot Points as an alternative to classical parameterization approaches, introduce great flexibility when calibrating heterogeneous systems without neglecting expert knowledge (Doherty, 2003). A highly parameterized optimization of complex distributed hydrological models at catchment scale is challenging due to the computational burden that comes with it. In this study the physically-based coupled surface-subsurface model MIKE SHE is calibrated for the 8,500 km2 area of central Jylland (Denmark) that is characterized by heterogeneous geology and considerable groundwater flow across topographical catchment boundaries. The calibration of the distributed conductivity fields is carried out with a pilot point-based approach, implemented using the PEST parameter estimation tool. To reduce the high number of calibration parameters, PEST's advanced singular value decomposition combined with regularization was utilized and a reduction of the model's complexity was

  9. A physically-based parsimonious hydrological model for flash floods in Mediterranean catchments

    Directory of Open Access Journals (Sweden)

    H. Roux

    2011-09-01

    Full Text Available A spatially distributed hydrological model, dedicated to flood simulation, is developed on the basis of physical process representation (infiltration, overland flow, channel routing. Estimation of model parameters requires data concerning topography, soil properties, vegetation and land use. Four parameters are calibrated for the entire catchment using one flood event. Model sensitivity to individual parameters is assessed using Monte-Carlo simulations. Results of this sensitivity analysis with a criterion based on the Nash efficiency coefficient and the error of peak time and runoff are used to calibrate the model. This procedure is tested on the Gardon d'Anduze catchment, located in the Mediterranean zone of southern France. A first validation is conducted using three flood events with different hydrometeorological characteristics. This sensitivity analysis along with validation tests illustrates the predictive capability of the model and points out the possible improvements on the model's structure and parameterization for flash flood forecasting, especially in ungauged basins. Concerning the model structure, results show that water transfer through the subsurface zone also contributes to the hydrograph response to an extreme event, especially during the recession period. Maps of soil saturation emphasize the impact of rainfall and soil properties variability on these dynamics. Adding a subsurface flow component in the simulation also greatly impacts the spatial distribution of soil saturation and shows the importance of the drainage network. Measures of such distributed variables would help discriminating between different possible model structures.

  10. Pursuing realistic hydrologic model under SUPERFLEX framework in a semi-humid catchment in China

    Science.gov (United States)

    Wei, Lingna; Savenije, Hubert H. G.; Gao, Hongkai; Chen, Xi

    2016-04-01

    Model realism is pursued perpetually by hydrologists for flood and drought prediction, integrated water resources management and decision support of water security. "Physical-based" distributed hydrologic models are speedily developed but they also encounter unneglectable challenges, for instance, computational time with low efficiency and parameters uncertainty. This study step-wisely tested four conceptual hydrologic models under the framework of SUPERFLEX in a small semi-humid catchment in southern Huai River basin of China. The original lumped FLEXL has hypothesized model structure of four reservoirs to represent canopy interception, unsaturated zone, subsurface flow of fast and slow components and base flow storage. Considering the uneven rainfall in space, the second model (FLEXD) is developed with same parameter set for different rain gauge controlling units. To reveal the effect of topography, terrain descriptor of height above the nearest drainage (HAND) combined with slope is applied to classify the experimental catchment into two landscapes. Then the third one (FLEXTOPO) builds different model blocks in consideration of the dominant hydrologic process corresponding to the topographical condition. The fourth one named FLEXTOPOD integrating the parallel framework of FLEXTOPO in four controlled units is designed to interpret spatial variability of rainfall patterns and topographic features. Through pairwise comparison, our results suggest that: (1) semi-distributed models (FLEXD and FLEXTOPOD) taking precipitation spatial heterogeneity into account has improved model performance with parsimonious parameter set, and (2) hydrologic model architecture with flexibility to reflect perceived dominant hydrologic processes can include the local terrain circumstances for each landscape. Hence, the modeling actions are coincided with the catchment behaviour and close to the "reality". The presented methodology is regarding hydrologic model as a tool to test our

  11. Snow modelling in a glacierized catchment using scale-dependent calibration data

    Science.gov (United States)

    Engel, Michael; Comiti, Francesco; Penna, Daniele; Notarnicola, Claudia; Bertoldi, Giacomo

    2013-04-01

    Physically-based hydrological models that integrate a large amount of parameters often face the problem of equifinality. Thus, the application of such models to Alpine catchments with high spatial heterogeneity and complex hydrological behaviour is challenging. In this context, the distributed hydrological model GEOtop was employed to simulate snow dynamics in the period 2010 - 2012 at different spatial scales within the Saldur basin (Eastern Italian Alps). In this catchment, hydrometric, isotopic and sediment transport data at different spatial scales are available to validate the model and to assess the physical consistency of the model output. This work aims to: (i) assess the model validation at the plot scale in order to improve performances at the catchment scale; (ii) verify the usefulness of using multiple types of observations (snow, satellites, tracers, discharge) in order to assess the physical consistency and reduce the equifinality of the model output. At the plot scale, the model was calibrated by a manual sensitivity analysis on predicted snow heights, water equivalent and duration compared with the corresponding snow depth data of two meteorological stations (at 1930 m and 3035 m a.s.l.) in the study area. Selected snow parameters controlling snow reflectivity and snow aging were calibrated. In addition to traditional snow depth data, photosynthetically active radiation (PAR) sensor data were used to derive snow duration of other four meteorological stations In order to account for the spatial distribution of snow cover, best parameter settings of the plot scale models were transferred to catchment scale models. These models were assigned for two nested catchments, named LSG (19 km²) and USG (11 km²), which provided snow height and SWE in the catchment. At this scale, the model calibration was based on two types of remotely sensed snow maps: monthly Landsat images (30 m of resolution) and daily MODIS images (250 m of resolution). To support the

  12. Modelling of catchment nitrogen concentrations response to observed varying fertilizer application intensities

    Science.gov (United States)

    Jomaa, Seifeddine; Jiang, Sanyuan; Yang, Xiaoqiang; Rode, Michael

    2016-04-01

    Eutrophication is a serious environmental problem. Despite numerous experimental and modelling efforts, understanding of the effect of land use and agriculture practices on in-stream nitrogen fluxes is still not fully achieved. This study combined intensive field monitoring and numerical modelling using 30 years of surface water quality data of a drinking water reservoir catchment in central Germany. The Weida catchment (99.5 km2) is part of the Elbe river basin and has a share of 67% of agricultural land use with significant changes in agricultural practices within the investigation period. The geology of the Weida catchment is characterized by clay schists and eruptive rocks, where rocks have low permeability. The semi-distributed hydrological water quality HYPE (Hydrological Predictions for the Environment) model was used to reproduce the measured data. First, the model was calibrated for discharge and nitrate-N concentrations (NO3-N) during the period 1997-2000. Then, the HYPE model was validated successfully for three different periods 1983-1987, 1989-1996 and 2000-2003, which are charaterized by different fertilizer application rates (with lowest discharge prediction performance of NSE = 0.78 and PBIAS = 3.74%, considering calibration and validation periods). Results showed that the measured as well as simulated in-stream nitrate-N concentration respond quickly to fertilizer application changes (increase/decrease). This rapid response can be explained with short residence times of interflow and baseflow runoff components due to the hardrock geological properties of the catchment. Results revealed that the surface runoff and interflow are the most dominant runoff components. HYPE model could reproduce reasonably well the NO3-N daily loads for varying fertilizer application, when detailed input data in terms of crop management (field-specific survey) are considered.

  13. Modelling Pesticide Leaching At Column, Field and Catchment Scales I. Analysis of Soil Variability At Field and Catchment Scales

    Science.gov (United States)

    Gärdenäs, A.; Jarvis, N.; Alavi, G.

    The spatial variability of soil characteristics was studied in a small agricultural catch- ment (Vemmenhög, 9 km2) at the field and catchment scales. This analysis serves as a basis for assumptions concerning upscaling approaches used to model pesticide leaching from the catchment with the MACRO model (Jarvis et al., this meeting). The work focused on the spatial variability of two key soil properties for pesticide fate in soil, organic carbon and clay content. The Vemmenhög catchment (9 km2) is formed in a glacial till deposit in southernmost Sweden. The landscape is undulating (30 - 65 m a.s.l.) and 95 % of the area is used for crop production (winter rape, winter wheat, sugar beet and spring barley). The climate is warm temperate. Soil samples for or- ganic C and texture were taken on a small regular grid at Näsby Farm, (144 m x 144 m, sampling distance: 6-24 m, 77 points) and on an irregular large grid covering the whole catchment (sampling distance: 333 m, 46 points). At the field scale, it could be shown that the organic C content was strongly related to landscape position and height (R2= 73 %, p organic C content of hollows in the landscape is so high that they contribute little to the total loss of pesticides (Jarvis et al., this meeting). Clay content is also related to landscape position, being larger at the hilltop locations resulting in lower near-saturated hydraulic conductivity. Hence, macropore flow can be expected to be more pronounced (see also Roulier & Jarvis, this meeting). The variability in organic C was similar for the field and catchment grids, which made it possible to krige the organic C content of the whole catchment using data from both grids and an uneven lag distance.

  14. Space-time modeling of catchment scale drought characteristics

    NARCIS (Netherlands)

    Tallaksen, L.; Hisdal, H.; Lanen, van H.A.J.

    2009-01-01

    Drought may affect all components of the water cycle and covers commonly a large part of the catchment area. This paper examines drought propagation at the catchment scale using spatially aggregated drought characteristics and illustrates the importance of catchment processes in modifying the

  15. How should a rainfall-runoff model be parameterized in an almost ungauged catchment? A methodology tested on 609 catchments

    Science.gov (United States)

    Rojas-Serna, Claudia; Lebecherel, Laure; Perrin, Charles; Andréassian, Vazken; Oudin, Ludovic

    2016-06-01

    This paper examines catchments that are almost ungauged, i.e., catchments for which only a small number of point flow measurements are available. In these catchments, hydrologists may still need to simulate continuous streamflow time series using a rainfall-runoff model, and the methodology presented here allows using few point measurements for model parameterization. The method combines regional information (parameter sets of neighboring gauged stations) and local information (contributed by the point measurements) within a framework where the relative weight of each source of information is made dependent on the number of point measurements available. This approach is tested with two different hydrological models on a set of 609 catchments in France. The results show that on average a few flow measurements can significantly improve the simulation efficiency, and that 10 measurements can reduce the performance gap between the gauged and ungauged situations by more than 50%. The added value of regional information progressively decreases until being almost insignificant when sufficient flow measurements are available. Model parameters tend to come closer to the values obtained by calibration in fully gauged conditions as the number of point flow measurements increases.

  16. Effects of wildfire on catchment runoff response: a modeling approach to detect changes in snow-dominated forested catchments

    Science.gov (United States)

    Jan Seibert; Jeffrey J. McDonnell; Richard D. Woodsmith

    2010-01-01

    Wildfire is an important disturbance affecting hydrological processes through alteration of vegetation cover and soil characteristics. The effects of fire on hydrological systems at the catchment scale are not well known, largely because site specific data from both before and after wildfire are rare. In this study a modelling approach was employed for change detection...

  17. Application of spatially varying storage capacity model for runoff parameterization in semi-arid catchment

    Institute of Scientific and Technical Information of China (English)

    Li-liang REN; Gui-zuo WANG; Fang LU; Tian-fang FANG

    2009-01-01

    This paper introduces the method of designation of water storage capacity for each grid cell within a catchment, which considers topography, vegetation and soil synthetically. For the purpose of hydrological process simulation in semi-arid regions, a spatially varying storage capacity (VSC) model was developed based on the spatial distribution of water storage capacity and the vertical hybrid runoff mechanism. To verify the applicability of the VSC model, both the VSC model and a hybrid runoff model were used to simulate daily runoff processes in the catchment upstream of the Dianzi hydrological station from 1973 to 1979. The results showed that the annual average Nash-Sutcliffe coefficient was 0.80 for the VSC model, and only 0.67 for the hybrid runoff model. The higher annual average Nash-Sutcliffe coefficient of the VSC model means that this hydrological model can better simulate daily runoff processes in semi-arid regions. Furthermore, as a distributed hydrological model, the VSC model can be applied in regional water resource management.

  18. Application of spatially varying storage capacity model for runoff parameterization in semi-arid catchment

    Directory of Open Access Journals (Sweden)

    Li-liang REN

    2009-06-01

    Full Text Available This paper introduces the method of designation of water storage capacity for each grid cell within a catchment, which considers topography, vegetation and soil synthetically. For the purpose of hydrological process simulation in semi-arid regions, a spatially varying storage capacity (VSC model was developed based on the spatial distribution of water storage capacity and the vertical hybrid runoff mechanism. To verify the applicability of the VSC model, both the VSC model and a hybrid runoff model were used to simulate daily runoff processes in the catchment upstream of the Dianzi hydrological station from 1973 to 1979. The results showed that the annual average Nash-Sutcliffe coefficient was 0.80 for the VSC model, and only 0.67 for the hybrid runoff model. The higher annual average Nash-Sutcliffe coefficient of the VSC model means that this hydrological model can better simulate daily runoff processes in semi-arid regions. Furthermore, as a distributed hydrological model, the VSC model can be applied in regional water resource management.

  19. HESS Opinions Catchments as meta-organisms - a new blueprint for hydrological modelling

    Science.gov (United States)

    Savenije, Hubert H. G.; Hrachowitz, Markus

    2017-02-01

    Catchment-scale hydrological models frequently miss essential characteristics of what determines the functioning of catchments. The most important active agent in catchments is the ecosystem. It manipulates and partitions moisture in a way that supports the essential functions of survival and productivity: infiltration of water, retention of moisture, mobilization and retention of nutrients, and drainage. Ecosystems do this in the most efficient way, establishing a continuous, ever-evolving feedback loop with the landscape and climatic drivers. In brief, hydrological systems are alive and have a strong capacity to adjust themselves to prevailing and changing environmental conditions. Although most models take Newtonian theory at heart, as best they can, what they generally miss is Darwinian theory on how an ecosystem evolves and adjusts its environment to maintain crucial hydrological functions. In addition, catchments, such as many other natural systems, do not only evolve over time, but develop features of spatial organization, including surface or sub-surface drainage patterns, as a by-product of this evolution. Models that fail to account for patterns and the associated feedbacks miss a critical element of how systems at the interface of atmosphere, biosphere and pedosphere function. In contrast to what is widely believed, relatively simple, semi-distributed conceptual models have the potential to accommodate organizational features and their temporal evolution in an efficient way, a reason for that being that because their parameters (and their evolution over time) are effective at the modelling scale, and thus integrate natural heterogeneity within the system, they may be directly inferred from observations at the same scale, reducing the need for calibration and related problems. In particular, the emergence of new and more detailed observation systems from space will lead towards a more robust understanding of spatial organization and its evolution. This

  20. Modelling the effects of recent agricultural land use change on catchment flow and sediment generation

    Science.gov (United States)

    Escobar Ruiz, Veronica; Smith, Hugh; Blake, William

    2016-04-01

    Intensive agricultural practices can exacerbate runoff and soil erosion leading to detrimental impacts downstream. Physically-based models have previously been used to assess the impacts on flow and sediment transport in response to land use change, but there has been little investigation of the effect shorter-term changes linked to variations in the extent of cultivated land. The aim of this project is to quantify the impacts on flow generation and sediment transport of different catchment conditions related to both actual recent changes in agricultural land use as well as future change scenarios. To this end, a physically-based distributed hydrological model, SHETRAN was applied in the Blackwater catchment (12 km2) located in south-west England. Land cover was simulated on the basis of satellite-derived land cover maps (1990, 2000 and 2007) as well as a catchment-scale field survey (2011). Soils were represented in the model using five layers for five different soil types in which parameter values were varied in accordance with land use and literature values. Rainfall data (15 min) combined with monthly calculations of evapotranspiration using a simple temperature-based PE model were used to represent contemporary climatic conditions spanning 2010-2014. Calibration was undertaken for selected events during 2011 when land use information was concurrent with available flow and suspended sediment yield data. All land use simulations were then completed for the period 2010-2014 to enable the comparison of model outputs. This contribution will present preliminary results from these land use simulations alongside the effect of several future changes scenarios on catchment flow and sediment generation.

  1. Incorporating preferential flow into a 3D model of a forested headwater catchment

    Science.gov (United States)

    Glaser, Barbara; Jackisch, Conrad; Hopp, Luisa; Pfister, Laurent; Klaus, Julian

    2016-04-01

    Preferential flow plays an important role for water flow and solute transport. The inclusion of preferential flow, for example with dual porosity or dual permeability approaches, is a common feature in transport simulations at the plot scale. But at hillslope and catchment scales, incorporation of macropore and fracture flow into distributed hydrologic 3D models is rare, often due to limited data availability for model parameterisation. In this study, we incorporated preferential flow into an existing 3D integrated surface subsurface hydrologic model (HydroGeoSphere) of a headwater region (6 ha) of the forested Weierbach catchment in western Luxembourg. Our model philosophy was a strong link between measured data and the model setup. The model setup we used previously had been parameterised and validated based on various field data. But existing macropores and fractures had not been considered in this initial model setup. The multi-criteria validation revealed a good model performance but also suggested potential for further improvement by incorporating preferential flow as additional process. In order to pursue the data driven model philosophy for the implementation of preferential flow, we analysed the results of plot scale bromide sprinkling and infiltration experiments carried out in the vicinity of the Weierbach catchment. Three 1 sqm plots were sprinkled for one hour and excavated one day later for bromide depth profile sampling. We simulated these sprinkling experiments at the soil column scale, using the parameterisation of the base headwater model extended by a second permeability domain. Representing the bromide depth profiles was successful without changing this initial parameterisation. Moreover, to explain the variability between the three bromide depth profiles it was sufficient to adapt the dual permeability properties, indicating the spatial heterogeneity of preferential flow. Subsequently, we incorporated the dual permeability simulation in the

  2. Modelling (flash) floods in a Dutch lowland catchment

    Science.gov (United States)

    Brauer, C. C.; Teuling, A. J.; Overeem, A.; van der Velde, Y.; Hazenberg, P.; Warmerdam, P. M. M.; Kloosterman, P.; Uijlenhoet, R.

    2012-04-01

    On 26 August 2010 the eastern part of The Netherlands and the bordering part of Germany were struck by a series of rainfall events. We investigated the unprecedented flash flood triggered by this exceptionally heavy rainfall event (return period > 1000 years) in the 6.5 km2 Hupsel Brook catchment, which has been the experimental watershed employed by Wageningen University since the 1960s. This study improved our understanding of the dynamics of such lowland flash floods and the results have been published in HESS (Brauer et al., 2011). During this extreme event some thresholds became apparent that do not play a role during average conditions and are not incorporated in rainfall-runoff models. We present a detailed analysis of this extreme event, focusing on (1) the measured soil moisture, groundwater and discharge response of the catchment, (2) the thresholds we found, (3) the manner in which these processes and thresholds are incorporated in some well-known conceptual hydrological models and (4) how well these models are able to simulate the rainfall-runoff processes during the 2010 flash flood.

  3. Assessment of runoff contributing catchment areas in rainfall runoff modelling

    DEFF Research Database (Denmark)

    Thorndahl, Søren; Johansen, C.; Schaarup-Jensen, Kjeld

    2006-01-01

    recommended literature values for residential areas. It is proven by comparing rainfall-runoff measurements from four different residential catchments that the literature values of the hydrological reduction factor are over-estimated for this type of catchment. In addition, different catchment descriptions...... are presented in order to investigate how the hydrological reduction factor depends on the level of detail regarding the catchment description. When applying a total survey of the catchment area, including all possible impervious surfaces, a hydrological reduction factor of approximately 0.5 for residential...

  4. Assessment of Runoff Contributing Catchment Areas in Rainfall Runoff Modelling

    DEFF Research Database (Denmark)

    Thorndahl, Søren Liedtke; Johansen, C.; Schaarup-Jensen, Kjeld

    2005-01-01

    recommended literary values for residential areas. It is proven by comparing rainfall-runoff measurements from four different residential catchments that the literary values of the hydrological reduction factor are over-estimated for this type of catchments. In addition, different catchment descriptions...... are presented in order to investigate how the hydrological reduction factor depends on the level of detail regarding the catchment description. When applying a total survey of the catchment area, including all possible impervious surfaces, a hydrological reduction factor of approximately 0.5 for residential...

  5. An appraisal of precipitation distribution in the high-altitude catchments of the Indus basin.

    Science.gov (United States)

    Dahri, Zakir Hussain; Ludwig, Fulco; Moors, Eddy; Ahmad, Bashir; Khan, Asif; Kabat, Pavel

    2016-04-01

    Scarcity of in-situ observations coupled with high orographic influences has prevented a comprehensive assessment of precipitation distribution in the high-altitude catchments of Indus basin. Available data are generally fragmented and scattered with different organizations and mostly cover the valleys. Here, we combine most of the available station data with the indirect precipitation estimates at the accumulation zones of major glaciers to analyse altitudinal dependency of precipitation in the high-altitude Indus basin. The available observations signified the importance of orography in each sub-hydrological basin but could not infer an accurate distribution of precipitation with altitude. We used Kriging with External Drift (KED) interpolation scheme with elevation as a predictor to appraise spatiotemporal distribution of mean monthly, seasonal and annual precipitation for the period of 1998-2012. The KED-based annual precipitation estimates are verified by the corresponding basin-wide observed specific runoffs, which show good agreement. In contrast to earlier studies, our estimates reveal substantially higher precipitation in most of the sub-basins indicating two distinct rainfall maxima; 1st along southern and lower most slopes of Chenab, Jhelum, Indus main and Swat basins, and 2nd around north-west corner of Shyok basin in the central Karakoram. The study demonstrated that the selected gridded precipitation products covering this region are prone to significant errors. In terms of quantitative estimates, ERA-Interim is relatively close to the observations followed by WFDEI and TRMM, while APHRODITE gives highly underestimated precipitation estimates in the study area. Basin-wide seasonal and annual correction factors introduced for each gridded dataset can be useful for lumped hydrological modelling studies, while the estimated precipitation distribution can serve as a basis for bias correction of any gridded precipitation products for the study area

  6. Global, continental and regional water balance estimates from HYPE catchment modelling

    Science.gov (United States)

    Arheimer, Berit; Andersson, Jafet; Crochemore, Louise; Donnelly, Chantal; Gustafsson, David; Hasan, Abdoulghani; Isberg, Kristina; Pechlivanidis, Ilias; Pimentel, Rafael; Pineda, Luis

    2017-04-01

    In the past, catchment modelling mainly focused on simulating the lumped hydrological cycle at local to regional domains with high precision in a specific point of a river. Today, the level of maturity in hydrological process descriptions, input data and methods for parameter constraints makes it possible to apply these models also for multi-basins over large domains, still using the catchment modellers approach with high demands on agreement with observed data. HYPE is a process-oriented, semi-distributed and open-source model concept that is developed and used operationally in Sweden since a decade. Its finest calculation unit is hydrological response units (HRUs) in a catchment and these are assumed to give the same rainfall-runoff response. HRUs are normally made up of similar land cover and management, combined with soil type or elevation. Water divides are retrieved from topography and calculations are integrated for catchments, which can be of different spatial resolution and are coupled along the river network. In each catchment, HYPE calculates the water balance of a given time-step separately for various hydrological storages, such glaciers, active soil, groundwater, river channels, wetlands, floodplains, and lakes. The model is calibrated in a step-wise manner (following the water path-ways) against various sources additional data sources, including in-situ observations, Earth Observation products, soft information and expert judgements (Arheimer et al., 2012; Donnelly et al, 2016; Pechlivanidis and Arheimer 2015). Both the HYPE code and the model set-ups (i.e. input data and parameter values) are frequently released in new versions as they are continuously improved and updated. This presentation will show the results of aggregated water-balance components over large domains, such as the Arctic basin, the European continent, the Indian subcontinent and the Niger River basin. These can easily be compared to results from other kind of large-scale modelling

  7. Assessment of Climate Change Impacts on Water Resources in Three Representative Ukrainian Catchments Using Eco-Hydrological Modelling

    Directory of Open Access Journals (Sweden)

    Iulii Didovets

    2017-03-01

    Full Text Available The information about climate change impact on river discharge is vitally important for planning adaptation measures. The future changes can affect different water-related sectors. The main goal of this study was to investigate the potential water resource changes in Ukraine, focusing on three mesoscale river catchments (Teteriv, Upper Western Bug, and Samara characteristic for different geographical zones. The catchment scale watershed model—Soil and Water Integrated Model (SWIM—was setup, calibrated, and validated for the three catchments under consideration. A set of seven GCM-RCM (General Circulation Model-Regional Climate Model coupled climate scenarios corresponding to RCPs (Representative Concentration Pathways 4.5 and 8.5 were used to drive the hydrological catchment model. The climate projections, used in the study, were considered as three combinations of low, intermediate, and high end scenarios. Our results indicate the shifts in the seasonal distribution of runoff in all three catchments. The spring high flow occurs earlier as a result of temperature increases and earlier snowmelt. The fairly robust trend is an increase in river discharge in the winter season, and most of the scenarios show a potential decrease in river discharge in the spring.

  8. CNMM: a Catchment Environmental Model for Managing Water Quality and Greenhouse Gas Emissions

    Science.gov (United States)

    Li, Y.

    2015-12-01

    Mitigating agricultural diffuse pollution and greenhouse gas emissions is a complicated task due to tempo-spatial lags between the field practices and the watershed responses. Spatially-distributed modeling is essential to the implementation of cost-effective and best management practices (BMPs) to optimize land uses and nutrient applications as well as to project the impact of climate change on the watershed service functions. CNMM (the Catchment Nutrients Management Model) is a 3D spatially-distributed, grid-based and process-oriented biophysical model comprehensively developed to simulate energy balance, hydrology, plant/crop growth, biogeochemistry of life elements (e.g., C, N and P), waste treatment, waterway vegetation/purification, stream water quality and land management in agricultural watersheds as affected by land utilization strategies such as BMPs and by climate change. The CNMM is driven by a number of spatially-distributed data such as weather, topography (including DEM and shading), stream network, stream water, soil, vegetation and land management (including waste treatments), and runs at an hourly time step. It represents a catchment as a matrix of square uniformly-sized cells, where each cell is defined as a homogeneous hydrological response unit with all the hydrologically-significant parameters the same but varied at soil depths in fine intervals. Therefore, spatial variability is represented by allowing parameters to vary horizontally and vertically in space. A four-direction flux routing algorithm is applied to route water and nutrients across soils of cells governed by the gradients of either water head or elevation. A linear channel reservoir scheme is deployed to route water and nutrients in stream networks. The model is capable of computing CO2, CH4, NH3, NO, N2O and N2 emissions from soils and stream waters. The CNMM can serve as an idea modelling tool to investigate the overwhelming critical zone research at various catchment scales.

  9. Soil Erosion Prediction Using Morgan-Morgan-Finney Model in a GIS Environment in Northern Ethiopia Catchment

    Directory of Open Access Journals (Sweden)

    Gebreyesus Brhane Tesfahunegn

    2014-01-01

    Full Text Available Even though scientific information on spatial distribution of hydrophysical parameters is critical for understanding erosion processes and designing suitable technologies, little is known in Geographical Information System (GIS application in developing spatial hydrophysical data inputs and their application in Morgan-Morgan-Finney (MMF erosion model. This study was aimed to derive spatial distribution of hydrophysical parameters and apply them in the Morgan-Morgan-Finney (MMF model for estimating soil erosion in the Mai-Negus catchment, northern Ethiopia. Major data input for the model include climate, topography, land use, and soil data. This study demonstrated using MMF model that the rate of soil detachment varied from 170 t ha−1 y−1, whereas the soil transport capacity of overland flow (TC ranged from 5 t ha−1 y−1 to >42 t ha−1 y−1. The average soil loss estimated by TC using MMF model at catchment level was 26 t ha−1 y−1. In most parts of the catchment (>80%, the model predicted soil loss rates higher than the maximum tolerable rate (18 t ha−1 y−1 estimated for Ethiopia. Hence, introducing appropriate interventions based on the erosion severity predicted by MMF model in the catchment is crucial for sustainable natural resources management.

  10. Applying profile- and catchment-based mathematical models for evaluating the run-off from a Nordic catchment

    Directory of Open Access Journals (Sweden)

    Farkas Csilla

    2016-09-01

    Full Text Available Knowledge of hydrological processes and water balance elements are important for climate adaptive water management as well as for introducing mitigation measures aiming to improve surface water quality. Mathematical models have the potential to estimate changes in hydrological processes under changing climatic or land use conditions. These models, indeed, need careful calibration and testing before being applied in decision making. The aim of this study was to compare the capability of five different hydrological models to predict the runoff and the soil water balance elements of a small catchment in Norway. The models were harmonised and calibrated against the same data set. In overall, a good agreement between the measured and simulated runoff was obtained for the different models when integrating the results over a week or longer periods. Model simulations indicate that forest appears to be very important for the water balance in the catchment, and that there is a lack of information on land use specific water balance elements. We concluded that joint application of hydrological models serves as a good background for ensemble modelling of water transport processes within a catchment and can highlight the uncertainty of models forecast.

  11. Spatial and Temporal Distribution of Soil Moisture at the Catchment Scale Using Remotely-Sensed Energy Fluxes

    Directory of Open Access Journals (Sweden)

    Thomas K. Alexandridis

    2016-01-01

    Full Text Available Despite playing a critical role in the division of precipitation between runoff and infiltration, soil moisture (SM is difficult to estimate at the catchment scale and at frequent time steps, as is required by many hydrological, erosion and flood simulation models. In this work, an integrated methodology is described to estimate SM at the root zone, based on the remotely-sensed evaporative fraction (Λ and ancillary information on soil and meteorology. A time series of Terra MODIS satellite images was used to estimate SM maps with an eight-day time step at a 250-m spatial resolution for three diverse catchments in Europe. The study of the resulting SM maps shows that their spatial variability follows the pattern of land cover types and the main geomorphological features of the catchment, and their temporal pattern follows the distribution of rain events, with the exception of irrigated land. Field surveys provided in situ measurements to validate the SM maps’ accuracy, which proved to be variable according to site and season. In addition, several factors were analyzed in order to explain the variation in the accuracy, and it was shown that the land cover type, the soil texture class, the temporal difference between the datasets’ acquisition and the presence of rain events during the measurements played a significant role, rather than the often referred to scale difference between in situ and satellite observations. Therefore, the proposed methodology can be used operationally to estimate SM maps at the catchment scale, with a 250-m spatial resolution and an eight-day time step.

  12. Grope in the Dark - Hydrological modelling of the artificial Chicken Creek catchment without validation possibilities

    Science.gov (United States)

    Hölzel, H.; Rössler, O.; Diekkrüger, B.

    Environmental modelling is often reduced to a calibration-validation exercise in which a thorough understanding of the processes involved is less important than sophisticated parameter estimation tools. A problem occurs when no data are available for calibration and validation. To compare the ability of different models and modellers to describe the hydrological behaviour of ungauged catchments, a model comparison was initiated by Transregional Collaboration Research Centre 38 (SFB/TRR 38). The comparison was conducted in several consecutive stages, in which knowledge of the investigated artificial catchment of approximately 6 ha was enhanced stepwise. For modelling purposes, all basic input data were given, but neither discharge nor soil moisture measurements were provided. This hard information was supplemented stepwise by soft (qualitative) information mostly obtained by a field inspection after the first modelling stage. In this study, the process-based distributed Water balance Simulation Model (WaSiM-ETH) was applied. An initial perceptual model was developed without site-specific knowledge. Significant modifications to the perceptual model were conducted using the available soft information. These modifications resulted in more reliable water fluxes. The main changes, such as the importance of a sealed topsoil layer, vegetation development, initial conditions, and the effects of a small pond on discharge behaviour, were related to process understanding. Although hard information on the water balance was still missing, the qualitative behaviour of the model seemed to be realistic. This underlines the importance of soft information for successful modelling, which is especially important if ungauged catchments are to be investigated.

  13. Topographic control of snowpack distribution in a small catchment in the central Spanish Pyrenees: intra- and inter-annual persistence

    Directory of Open Access Journals (Sweden)

    J. Revuelto

    2014-04-01

    Full Text Available In this study we analyzed the relations between terrain characteristics and snow depth distribution in a small alpine catchment located in the central Spanish Pyrenees. Twelve field campaigns were conducted during 2012 and 2013, which were years characterized by very different climatic conditions. Snow depth was measured using a long range terrestrial laser scanner and analyses were performed at a spatial resolution of 5 m. Pearson's r correlation, multiple linear regressions and binary regression trees were used to analyze the influence of topography on the snow depth distribution. The analyses were used to identify the topographic variables that better explain the snow distribution in this catchment, and to assess whether their contributions were variable over intra- and inter-annual time scales. The topographic position index, which has rarely been used in these types of studies, most accurately explained the distribution of snow accumulation. Other variables affecting the snow depth distribution included the maximum upwind slope, elevation, and northing (or potential incoming solar radiation. The models developed to predict snow distribution in the basin for each of the 12 survey days were similar in terms of the most explanatory variables. However, the variance explained by the overall model and by each topographic variable, especially those making a lesser contribution, differed markedly between a year in which snow was abundant (2013 and a~year when snow was scarce (2012, and also differed between surveys in which snow accumulation or melting conditions dominated in the preceding days. The total variance explained by the models clearly decreased for those days on which the snow pack was thinner and more patchily distributed. Despite the differences in climatic conditions in the 2012 and 2013 snow seasons, some similarities in snow accumulation patterns were observed.

  14. Model-based analysis of the influence of catchment properties on hydrologic partitioning across five mountain headwater subcatchments.

    Science.gov (United States)

    Kelleher, Christa; Wagener, Thorsten; McGlynn, Brian

    2015-06-01

    Ungauged headwater basins are an abundant part of the river network, but dominant influences on headwater hydrologic response remain difficult to predict. To address this gap, we investigated the ability of a physically based watershed model (the Distributed Hydrology-Soil-Vegetation Model) to represent controls on metrics of hydrologic partitioning across five adjacent headwater subcatchments. The five study subcatchments, located in Tenderfoot Creek Experimental Forest in central Montana, have similar climate but variable topography and vegetation distribution. This facilitated a comparative hydrology approach to interpret how parameters that influence partitioning, detected via global sensitivity analysis, differ across catchments. Model parameters were constrained a priori using existing regional information and expert knowledge. Influential parameters were compared to perceptions of catchment functioning and its variability across subcatchments. Despite between-catchment differences in topography and vegetation, hydrologic partitioning across all metrics and all subcatchments was sensitive to a similar subset of snow, vegetation, and soil parameters. Results also highlighted one subcatchment with low certainty in parameter sensitivity, indicating that the model poorly represented some complexities in this subcatchment likely because an important process is missing or poorly characterized in the mechanistic model. For use in other basins, this method can assess parameter sensitivities as a function of the specific ungauged system to which it is applied. Overall, this approach can be employed to identify dominant modeled controls on catchment response and their agreement with system understanding.

  15. Quantifying and Modelling Long Term Sediment Dynamics in Catchments in Western Europe

    Science.gov (United States)

    Notebaert, B.; De Brue, H.; Verstraeten, G.; Broothaerts, N.

    2015-12-01

    Quantification of sediment dynamics allows to get insight in driving forces and internal dynamics of the sediment cascade system. A useful tool to achieve this is the sediment budget approach, which encompasses the quantification of different sinks and sources. A Holocene time-differentiated sediment budget has been constructed for the Belgian Dijle River catchment (720 km²), based on a large set of field data. The results show how soil erosion is driven by land use changes over longer timescales. Sediment redistribution and the relative importance of the different sinks also vary over time, mainly as a result of changing land use and related landscape connectivity. However, the coarse temporal resolution typically associated with Holocene studies complicates the understanding of sub-millennial scale processes. In a second step, the field-based sediment budget was combined with a modeling approach using Watem/Sedem, a spatially distributed model that simulates soil erosion and colluvial deposition. After validation of the model calibration against the sediment budget, the model was used in a sensitivity analysis. Results confirm the overwhelming influence of human land use on both soil erosion and landscape connectivity, whereas the climatic impact is comparatively small. In addition to catchment-wide simulations, the model also served to test the relative importance of lynchets and dry valleys in different environments. Finally, the geomorphic model was used to simulate past land use, taking into account equifinality. For this purpose, a large series of hypothetical time-independent land use maps of the Dijle catchment were modeled based on a multi-objective allocation algorithm, and applied in Watem/Sedem. Modeled soil erosion and sediment deposition outcomes for each scenario were subsequently compared with the field-based record, taking into account uncertainties. As such, the model allows to evaluate and select realistic land use scenarios for the Holocene.

  16. Modeling Hydrologic Transport through the Critical Zone: Lessons from Catchment-Scale and Lysimeter Studies

    Science.gov (United States)

    Benettin, P.; Queloz, P.; Bailey, S. W.; McGuire, K. J.; Rinaldo, A.; Botter, G.

    2015-12-01

    Water age distributions can be used to address a number of environmental challenges, such as modeling the dynamics of river water quality, quantifying the interactions between shallow and deep flow systems and understanding nutrient loading persistence. Moreover, as the travel time of a water particle is the time available for biogeochemical reactions, it can be explicitly used to predict the concentration of non-conservative solutes, as e.g. those derived by mineral weathering. In recent years, many studies acknowledged the dynamic nature of streamflow age and linked it to observed variations in stream water quality. In this new framework, water stored within a catchment can be seen as a pool that is selectively "sampled" by streams and vegetation, determining the chemical composition of discharge and evapotranspiration. We present results from a controlled lysimeter experiment and real-world catchments, where the theoretical framework has been used to reproduce water quality datasets including conservative tracers (e.g. chloride and water stable isotopes) and weathering-derived solutes (like silicon and sodium). The approach proves useful to estimate the catchment water storage involved in solute mixing and sheds light on how solutes and water of different ages are selectively removed by vegetation and soil drainage.

  17. Integrated Modelling of Climate Change Impacts in an Irrigated, Semi-arid Catchment

    Science.gov (United States)

    Haslauer, C. P.; von Gunten, D.; Wöhling, T.; Rudolph, D. L.; Cirpka, O. A.

    2015-12-01

    Predicting the impacts of climate change on hydrological processes is a central challenge for water management. Commonly, studies on climate-change effects focus on surface flow and feed-backs between surface and subsurface flows are neglected frequently. Furthermore, changes in hydrological processes are generally not distributed realistically. Integrated catchment models, based on partial-differential-equations, have the potential of overcoming these difficulties. However, these models are complicated to use in realistic settings, notably because of their long simulation time. In this presentation, we demonstrate a successful application of an integrated catchment model (HydroGeoSphere) in a semi-arid catchment in north-east Spain. The study area recently underwent a transition to irrigated agriculture, which is reflected in our model evaluations conducted under varying irrigation conditions. To accelerate model calibration, we developed a novel calibration method based on a hierarchy of computational grids. The climate scenarios for the region are based on four regional climate models, which are downscaled using a weather generator. These scenarios are used to estimate climate change impacts on hydrologic parameters in different irrigation settings. The effects of climate change strongly depend on the presence of irrigation. Water table depth and low flows are more sensitive to climate change when irrigation is present, while peak flows exhibit a more pronounced response to climate in scenarios without irrigation. In addition to the climatic means, we examined the impacts of changes in drought conditions. We compare the outcomes of droughts predicted by our hydrological model with simpler approaches based on drought indices. We show that drought indices oversimplify future hydrological impacts of droughts and can result in biased estimation of drought impacts, especially if drought indices do not take temperature changes into account.

  18. Assessment of LULC and climate change on the hydrology of Ashti Catchment, India using VIC model

    Indian Academy of Sciences (India)

    Narendra Hengade; T I Eldho

    2016-12-01

    The assessment of land use land cover (LULC) and climate change over the hydrology of a catchment has become inevitable and is an essential aspect to understand the water resources-related problems within the catchment. For large catchments, mesoscale models such as variable infiltration capacity (VIC) model are required for appropriate hydrological assessment. In this study, Ashti Catchment (sub-catchment of Godavari Basin in India) is considered as a case study to evaluate the impacts of LULC changes and rainfall trends on the hydrological variables using VIC model. The land cover data and rainfall trends for 40 years (1971−2010) were used as driving input parameters to simulate the hydrological changes over the Ashti Catchment and the results are compared with observed runoff. The good agreement between observed and simulated streamflows emphasises that the VIC model is able to evaluate the hydrological changes within the major catchment, satisfactorily. Further, the study shows that evapotranspiration is predominantly governed by the vegetation classes. Evapotranspiration is higher for the forest cover as compared to the evapotranspiration for shrubland/grassland, as the trees with deeper roots draws the soil moisture from the deeper soil layers. The results show that the spatial extent of change in rainfall trends is small as compared to the total catchment. The hydrological response of the catchment shows that small changes in monsoon rainfall predominantly contribute to runoff, which results in higher changes in runoff as the potential evapotranspiration within the catchments is achieved. The study also emphasises that the hydrological implications of climate change are not very significant on the Ashti Catchment, during the last 40 years (1971−2010).

  19. Assessment of LULC and climate change on the hydrology of Ashti Catchment, India using VIC model

    Science.gov (United States)

    Hengade, Narendra; Eldho, T. I.

    2016-12-01

    The assessment of land use land cover (LULC) and climate change over the hydrology of a catchment has become inevitable and is an essential aspect to understand the water resources-related problems within the catchment. For large catchments, mesoscale models such as variable infiltration capacity (VIC) model are required for appropriate hydrological assessment. In this study, Ashti Catchment (sub-catchment of Godavari Basin in India) is considered as a case study to evaluate the impacts of LULC changes and rainfall trends on the hydrological variables using VIC model. The land cover data and rainfall trends for 40 years (1971-2010) were used as driving input parameters to simulate the hydrological changes over the Ashti Catchment and the results are compared with observed runoff. The good agreement between observed and simulated streamflows emphasises that the VIC model is able to evaluate the hydrological changes within the major catchment, satisfactorily. Further, the study shows that evapotranspiration is predominantly governed by the vegetation classes. Evapotranspiration is higher for the forest cover as compared to the evapotranspiration for shrubland/grassland, as the trees with deeper roots draws the soil moisture from the deeper soil layers. The results show that the spatial extent of change in rainfall trends is small as compared to the total catchment. The hydrological response of the catchment shows that small changes in monsoon rainfall predominantly contribute to runoff, which results in higher changes in runoff as the potential evapotranspiration within the catchments is achieved. The study also emphasises that the hydrological implications of climate change are not very significant on the Ashti Catchment, during the last 40 years (1971-2010).

  20. Catchment & sewer network simulation model to benchmark control strategies within urban wastewater systems

    DEFF Research Database (Denmark)

    Saagi, Ramesh; Flores Alsina, Xavier; Fu, Guangtao

    2016-01-01

    This paper aims at developing a benchmark simulation model to evaluate control strategies for the urban catchment and sewer network. Various modules describing wastewater generation in the catchment, its subsequent transport and storage in the sewer system are presented. Global/local overflow bas...

  1. A long-term data set for hydrologic modeling in a snow-dominated mountain catchment

    Science.gov (United States)

    An hourly modeling data set is presented for the water years 1984 through 2008 for a snow-dominated headwater catchment. Meteorological forcing data and GIS watershed characteristics are described and provided. The meteorological data are measured at two sites within the catchment, and include pre...

  2. Modelling long-term (300ka) upland catchment response to multiple lava damming events

    NARCIS (Netherlands)

    van Gorp, W.; Temme, A. J. A. M.; Veldkamp, A.; Schoorl, J. M.

    2015-01-01

    Landscapes respond in complex ways to external drivers such as base level change due to damming events. In this study, landscape evolution modelling was used to understand and analyse long-term catchment response to lava damming events. PalaeoDEM reconstruction of a small Turkish catchment (45km(2))

  3. Modelling long-term (300¿ka) upland catchment response to multiple lava damming events

    NARCIS (Netherlands)

    Gorp, van W.; Temme, A.J.A.M.; Veldkamp, A.; Schoorl, J.M.

    2015-01-01

    Landscapes respond in complex ways to external drivers such as base level change due to damming events. In this study, landscape evolution modelling was used to understand and analyse long-term catchment response to lava damming events. PalaeoDEM reconstruction of a small Turkish catchment (45¿km2)

  4. Water balance modeling of Upper Blue Nile catchments using a top-down approach

    NARCIS (Netherlands)

    Tekleab, S.; Uhlenbrook, S.; Mohamed, Y.; Savenije, H.H.G.; Temesgen, M.; Wenninger, J.

    2011-01-01

    The water balances of twenty catchments in the Upper Blue Nile basin have been analyzed using a top-down modeling approach based on Budyko’s hypotheses. The objective of this study is to obtain better understanding of water balance dynamics of upper Blue Nile catchments on annual and monthly time sc

  5. Ecohydrological modelling and integrated management planning in the catchment of the river Dommel

    NARCIS (Netherlands)

    Verkroost, A.W.M.; Olde Venterink, H.; Pieterse, N.M.; Schot, P.P.; Wassen, M.J.

    1998-01-01

    The EU-LIFE Dommel project aims at the development of methods for the combined use of landscape ecological models and socio-economic knowledge in the drawing up of integrated management plans for catchment areas of small trans-border rivers. These methods were developed and tested in the catchment a

  6. Controls on inorganic nitrogen leaching from Finnish catchments assessed using a sensitivity and uncertainty analysis of the INCA-N model

    Energy Technology Data Exchange (ETDEWEB)

    Rankinen, K.; Granlund, K. [Finnish Environmental Inst., Helsinki (Finland); Futter, M. N. [Swedish Univ. of Agricultural Sciences, Uppsala (Sweden)

    2013-11-01

    The semi-distributed, dynamic INCA-N model was used to simulate the behaviour of dissolved inorganic nitrogen (DIN) in two Finnish research catchments. Parameter sensitivity and model structural uncertainty were analysed using generalized sensitivity analysis. The Mustajoki catchment is a forested upstream catchment, while the Savijoki catchment represents intensively cultivated lowlands. In general, there were more influential parameters in Savijoki than Mustajoki. Model results were sensitive to N-transformation rates, vegetation dynamics, and soil and river hydrology. Values of the sensitive parameters were based on long-term measurements covering both warm and cold years. The highest measured DIN concentrations fell between minimum and maximum values estimated during the uncertainty analysis. The lowest measured concentrations fell outside these bounds, suggesting that some retention processes may be missing from the current model structure. The lowest concentrations occurred mainly during low flow periods; so effects on total loads were small. (orig.)

  7. Application of The Hydrology Lab Research Modeling System (hl-rms) For Large Headwater Catchments

    Science.gov (United States)

    Koren, V.; Smith, M.; Reed, S.; Zhang, Z.

    The Hydrology Lab (HL) of the National Weather Service Office of Hydrologic De- velopment is actively engaged in research and development into catchment modeling approaches to improve the ability to forecast river flows. Traditionally, conceptual lumped models have been used to produce operational river forecasts, and they of- ten produce reasonable results provided their parameters were calibrated properly. A common hypothesis in the scientific community attributes this success primarily to a model parameter calibration without regard a model structure. It is also commonly assumed that distributed models will provide better results just because they account for the spatial variability of input data and parameters. However, experience suggests that there are advantages and disadvantages of lumped and distributed models due to the combined effects of model structure and parameter estimation procedures. Neither physically poor models with advanced parameter estimation procedures, nor physi- cally advanced models with poor parameter estimation procedures can provide reason- able results. While most conceptual lumped models do not use explicitly the classical mass and momentum conservation equations, they incorporate strong physical con- cepts supported by field experiments. Their parameters represent integrated effects of basin properties on an outlet hydrograph, and as a result, they are identifiable from hydrograph analysis. On the other hand, most distributed models are based on point process equations, and distributed parameters are less identifiable from hydrograph analysis because they represent local properties. The authors believe that more com- prehensive analyses of lumped and distributed models on large-scale basins is needed to fully benefit from existing lumped modeling experience. As a Distributed Model Intercomparison Project (DMIP) initiative, HL has developed a grid-based Research Modeling System (HL-RMS) that combines lumped and distributed model

  8. Effects of input discretization, model complexity, and calibration strategy on model performance in a data-scarce glacierized catchment in Central Asia

    Science.gov (United States)

    Tarasova, L.; Knoche, M.; Dietrich, J.; Merz, R.

    2016-06-01

    Glacierized high-mountainous catchments are often the water towers for downstream region, and modeling these remote areas are often the only available tool for the assessment of water resources availability. Nevertheless, data scarcity affects different aspects of hydrological modeling in such mountainous glacierized basins. On the example of poorly gauged glacierized catchment in Central Asia, we examined the effects of input discretization, model complexity, and calibration strategy on model performance. The study was conducted with the GSM-Socont model driven with climatic input from the corrected High Asia Reanalysis data set of two different discretizations. We analyze the effects of the use of long-term glacier volume loss, snow cover images, and interior runoff as an additional calibration data. In glacierized catchments with winter accumulation type, where the transformation of precipitation into runoff is mainly controlled by snow and glacier melt processes, the spatial discretization of precipitation tends to have less impact on simulated runoff than a correct prediction of the integral precipitation volume. Increasing model complexity by using spatially distributed input or semidistributed parameters values does not increase model performance in the Gunt catchment, as the more complex model tends to be more sensitive to errors in the input data set. In our case, better model performance and quantification of the flow components can be achieved by additional calibration data, rather than by using a more distributed model parameters. However, a semidistributed model better predicts the spatial patterns of snow accumulation and provides more plausible runoff predictions at the interior sites.

  9. Testing hypotheses of the functioning of a tropical catchment: evaluating the role of model-structural and observational uncertainties

    Science.gov (United States)

    Westerberg, I.; Birkel, C.

    2012-04-01

    Knowledge about hydrological processes and the spatial and temporal distribution of water resources is the basis for water management such as hydropower, agriculture and flood-protection. Conceptual hydrological models may be used to infer knowledge on catchment functioning but are affected by uncertainties in the model representation of reality as well as in the observational data used to drive the model and to evaluate model performance. Therefore, meaningful hypotheses testing of the hydrological functioning of a catchment requires such uncertainties to be carefully estimated and accounted for in model calibration and evaluation. We investigated the hydrological functioning of the relatively data-scarce tropical Sarapiqui catchment in Costa Rica, Central America, where water resources play a vital part for hydropower production and livelihood. Hypotheses on catchment functioning using different model structures were tested within an uncertainty estimation framework specifically accounting for observational uncertainties. The uncertainty in discharge data was estimated from a rating-curve analysis and precipitation measurement errors through scenarios relating the error to, for example, the elevation gradient. The suitability of the different model structures as hypotheses about the functioning of the catchment was evaluated in a posterior analysis of the simulations. The performance of each simulation relative to the observational uncertainties was analysed for the entire hydrograph as well as for different aspects of the hydrograph (e.g. peak flows, recession periods, and base flow). This analysis enabled the identification of periods of likely model-structural errors and periods of probable data errors. We conclude that accounting for observational uncertainties led to improved hypotheses testing, which resulted in less risk of rejecting an acceptable model structure because of uncertainties in the forcing and evaluation data.

  10. A 3D model describing the initial structure of an artificial hydrological catchment

    Science.gov (United States)

    Maurer, T.; Schneider, A.; Buczko, U.; Gerke, H. H.

    2009-04-01

    The initial development stages of artificially constructed hydrologic catchments are characterized by the absence of vegetation, soil organic matter and soil horizons. This results in increased surface runoff and favors erosion processes that dominate the initial phase. Hydraulic conditions on artificial catchments thus are governed by rapidly changing surface structures as well as by the primary internal structural framework. Contemporary hydrological modeling does not consider any dynamic change of relevant structural features but rather assumes a stable, invariant landscape. The objective of this study was the digital visualization and quantitative description of the initial state and its early structural dynamics, exemplified for the small artificial hydrological catchment "Huehnerwasser" near Cottbus, Germany. Photogrammetric surveys of surface and internal structural units (clay basis liner) during the construction phase provided spatially and temporally resolved data for digital elevation models (DEM). Interpolated physical and chemical soil properties obtained at a borehole grid (e.g., texture) are used for the visualization of spatial distribution of relevant (hydraulic) parameters. The data are merged in a database and visualized in the 3D-GIS application GoCAD. The specific technological construction processes determines the internal structure of the artificial catchment. Resulting differences in bulk density and texture are supposed to have considerable impact on hydraulic properties. A structure generator program was implemented to reproduce the initial structure of the sediment layer as closely as possible. Results of the digital structure generation are checked with non-invasive geophysical measurements, on-site bore holes data and off-site 2D vertical spoil exploration. The accuracy of structure generator results will be compared with predictions of different interpolation methods. Thus, the structure model will serve as a basis for deriving the 3D-distributions

  11. Modeling the stream water nitrate dynamics in a 60,000-km2 European catchment, the Garonne, southwest France.

    Science.gov (United States)

    Tisseuil, Clément; Wade, Andrew J; Tudesque, Loïc; Lek, Sovan

    2008-01-01

    The spatial and temporal dynamics in the stream water NO(3)-N concentrations in a major European river-system, the Garonne (62,700 km(2)), are described and related to variations in climate, land management, and effluent point-sources using multivariate statistics. Building on this, the Hydrologiska Byråns Vattenbalansavdelning (HBV) rainfall-runoff model and the Integrated Catchment Model of Nitrogen (INCA-N) are applied to simulate the observed flow and N dynamics. This is done to help us to understand which factors and processes control the flow and N dynamics in different climate zones and to assess the relative inputs from diffuse and point sources across the catchment. This is the first application of the linked HBV and INCA-N models to a major European river system commensurate with the largest basins to be managed under the Water Framework Directive. The simulations suggest that in the lowlands, seasonal patterns in the stream water NO(3)-N concentrations emerge and are dominated by diffuse agricultural inputs, with an estimated 75% of the river load in the lowlands derived from arable farming. The results confirm earlier European catchment studies. Namely, current semi-distributed catchment-scale dynamic models, which integrate variations in land cover, climate, and a simple representation of the terrestrial and in-stream N cycle, are able to simulate seasonal NO(3)-N patterns at large spatial (>300 km(2)) and temporal (> or = monthly) scales using available national datasets.

  12. Distributed temperature measurements of a mountain stream for catchment hydrogeology understanding

    Science.gov (United States)

    Gance, Julien; Malet, Jean-Philippe; Sailhac, Pascal; Viville, Daniel; Pierret, Marie-Claire

    2015-04-01

    In mountain regions, natural water resources used for agriculture or drinking water generally come from natural sources. In this context, climate change that could result in the modification of the rainfall and of the snowcover characteristics during winter could impact natural water resources of the valley. The study of the hydrology at the catchment scale is therefore an important issue. To address this issue, we use Distributed Temperature Sensing (DTS) technology to monitor the variations of water temperature along a stream. This spatially distributed monitoring of temperature is used to assess the origin of the stream water (deep groundwater source, sub-surface water inflows…) in relation to the discharge of the stream and the rainfall conditions. The observation site if the Strengbach / OHGE catchment (Vosges massif, France). We installed an AP Sensing DTS device consisting in a datalogger and 850 m of reinforced fiber optic cable. The first 600 m have been installed directly in the stream and are underwater even for low water discharges; the next 200 m located upslope have been buried in the soil at depth in the main water source area of the catchment; finally the last 50 m are installed vertically in a borehole in the aquifer. We present a statistical analysis of a time series of 6 months of measurements. In the upper part of the stream, near the source area, the water temperature always remains close to the temperature of the aquifer (monitored in the borehole) indicating that the stream is mainly supplied by local resurgence of groundwater. In the lower part of the stream, the water temperature is more correlated to the air temperature. The analysis highlights several sections along the stream with diffuse lateral surface water arrivals, characterized by temperature anomalies.

  13. Large Catchment Scale Sediment Transport Modelling of SOC Using Environmental Tracers and Remote Sensing

    Science.gov (United States)

    Willgoose, G. R.; Kunkel, V.; Hancock, G. R.; Wells, T.

    2015-12-01

    Soil's potential as a carbon sink for atmospheric CO2 has been widely discussed. Studies of soil organic carbon (SOC) controls, and the subsequent models derived from their findings, have focussed mainly on North American and European regions, and more recently, in regions such as China. In Australia, agricultural practices have led to losses in SOC. This implies that Australian soils have a large potential for increased sequestration of SOC. Building on previous work, here we examine the spatial and temporal variation in soil organic carbon (SOC) and its controlling factors controls across a large catchment of approximately 650 km2 in the Upper Hunter Valley, New South Wales, Australia, using data collected from two sampling campaigns, (April 2006 and June-July 2014). The 2006 data represented a period of long-term drought which effectively ended in 2007 with average and above average subsequent rainfall. In 2007 and 2010 there were a series of extreme rainfall events. 137-Cesium and SOC concentrations were obtained from the sampled soils. Remote sensing using Landsat (30m) and MODIS (250m) NDVI was used to determine if catchment SOC could be predicted using both low and high resolution remote sensing. Relationships between SOC and 137-Cesium for both sampling periods were also quantified. Results indicate that, although moderate resolution (250 m) allows for reasonable prediction of the spatial distribution of SOC, the higher resolution (30 m) improved the strength of the SOC-NDVI relationship. Mean 137-Cesium concentrations were observed to show an increase in deposition at the sample sites over the 8 years between samplings. The relationship between SOC and 137-Cesium, as a surrogate for the erosion and deposition of SOC, suggested that sediment transport and deposition influences the distribution of SOC within the catchment. The increase in 137-Cesium also suggests that increased rainfall and extreme storm events, resulting from climate change, may increase

  14. Keeping it simple: a conceptual model of DOC dynamics in a subarctic alpine catchment

    Science.gov (United States)

    Lessels, J. S.; Tetzlaff, D.; Carey, S. K.; Soulsby, C.

    2013-12-01

    Understanding hydrological processes in subarctic alpine catchments characterised with discontinuous permafrost is important in order to understand carbon exports. Subarctic catchments have large storages of carbon in organic and permafrost soils. Active layer depth is one of the largest controlling factors of the release of dissolved organic carbon (DOC) due to its control on runoff pathways. Therefore, any change of this depth will affect the amount of DOC mobilised from these catchments. Simple low parameterised conceptual models offer the ability to characterise hydrological processes and linked DOC dynamics without introducing many of the uncertainties linked to high parameterised models. Lumped models can also be used to identify sources of DOC within catchments. Here, we investigate hydrological sources, flow pathways and consequently DOC dynamics in the Granger Basin, Canada, a subarctic alpine catchment using data collected from 2001 to 2008. The catchment is distinguished by aspect dependant discontinuous permafrost and seasonal frost, compounded further by differences in soil and vegetation types. Applying a simple low parameterised conceptual model allowed identification of the dominant flow paths of the main hydrological response units. The results showed that it was necessary to include active layer dynamics combined with aspect to represent the hydrological and DOC dynamics. The model provides information on the effect of climatic conditions on DOC releases. By identifying the key flow paths and relating these to spring freshet DOC exports over multiple years it is possible to gain an insight of the how climatic changes might affect hydrological processes within subarctic catchments.

  15. Predictions of rainfall-runoff response and soil moisture dynamics in a microscale catchment using the CREW model

    Science.gov (United States)

    Lee, H.; Zehe, E.; Sivapalan, M.

    2007-02-01

    Predictions of catchment hydrology have been performed generally using either physically based, distributed models or conceptual lumped or semi-distributed models. In recognition of the disadvantages of using either of these modeling approaches, namely, detailed data requirements in the case of distributed modeling, and lack of physical basis of conceptual/lumped model parameters, Reggiani et al. (1998, 1999) derived, from first principles and in a general manner, the balance equations for mass, momentum and energy at what they called the Representative Elementary Watershed (or REW) scale. However, the mass balance equations of the REW approach include mass exchange flux terms which must be defined externally before their application to real catchments. Developing physically reasonable "closure relations" for these mass exchange flux terms is a crucial pre-requisite for the success of the REW approach. As a guidance to the development of closure relations expressing mass exchange fluxes as functions of relevant state variables in a physically reasonable way, and in the process effectively parameterizing the effects of sub-grid or sub-REW heterogeneity of catchment physiographic properties on these mass exchange fluxes, this paper considers four different approaches, namely the field experimental approach, a theoretical/analytical approach, a numerical approach, and a hybrid approach combining one or more of the above. Based on the concept of the scaleway (Vogel and Roth, 2003) and the disaggregation-aggregation approach (Viney and Sivapalan, 2004), and using the data set from Weiherbach catchment in Germany, closure relations for infiltration, exfiltration and groundwater recharge were derived analytically, or on theoretical grounds, while numerical experiments with a detailed fine-scale, distributed model, CATFLOW, were used to obtain the closure relationship for seepage outflow. The detailed model, CATFLOW, was also used to derive REW scale pressure-saturation (i

  16. Predictions of rainfall-runoff response and soil moisture dynamics in a microscale catchment using the CREW model

    Directory of Open Access Journals (Sweden)

    H. Lee

    2007-01-01

    Full Text Available Predictions of catchment hydrology have been performed generally using either physically based, distributed models or conceptual lumped or semi-distributed models. In recognition of the disadvantages of using either of these modeling approaches, namely, detailed data requirements in the case of distributed modeling, and lack of physical basis of conceptual/lumped model parameters, Reggiani et al. (1998, 1999 derived, from first principles and in a general manner, the balance equations for mass, momentum and energy at what they called the Representative Elementary Watershed (or REW scale. However, the mass balance equations of the REW approach include mass exchange flux terms which must be defined externally before their application to real catchments. Developing physically reasonable "closure relations" for these mass exchange flux terms is a crucial pre-requisite for the success of the REW approach. As a guidance to the development of closure relations expressing mass exchange fluxes as functions of relevant state variables in a physically reasonable way, and in the process effectively parameterizing the effects of sub-grid or sub-REW heterogeneity of catchment physiographic properties on these mass exchange fluxes, this paper considers four different approaches, namely the field experimental approach, a theoretical/analytical approach, a numerical approach, and a hybrid approach combining one or more of the above. Based on the concept of the scaleway (Vogel and Roth, 2003 and the disaggregation-aggregation approach (Viney and Sivapalan, 2004, and using the data set from Weiherbach catchment in Germany, closure relations for infiltration, exfiltration and groundwater recharge were derived analytically, or on theoretical grounds, while numerical experiments with a detailed fine-scale, distributed model, CATFLOW, were used to obtain the closure relationship for seepage outflow. The detailed model, CATFLOW, was also used to derive REW scale

  17. Modelling overbank flow on farmed catchments taking into account spatial hydrological discontinuities

    Science.gov (United States)

    Moussa, R.; Tilma, M.; Chahinian, N.; Huttel, O.

    2003-04-01

    In agricultural catchments, hydrological processes are largely variable in space due to human impact causing hydrological discontinuities such as ditch network, field limits and terraces. The ditch network accelerates runoff by concentrating flows, drains the water table or replenishes it by reinfiltration of the runoff water. During extreme flood events, overbank flow occurs and surface pathflows are modified. The purpose of this study is to assess the influence of overbank flow on hydrograph shape during flood events. For that, MHYDAS, a physically based distributed hydrological model, was especially developed to take into account these hydrological discontinuities. The model considers the catchment as a series of interconnected hydrological unit. Runoff from each unit is estimated using a deterministic model based on the pounding-time algorithm and then routed through the ditch network using the diffusive wave equation. Overbank flow is modelled by modifying links between the hydrological units and the ditch network. The model was applied to simulate the main hydrological processes on a small headwater farmed Mediterranean catchment located in Southern France. The basic hydrometeorological equipment consists of a meteorological station, rain gauges, a tensio-neutronic and a piezometric measurement network, and eight water flow measurements. A multi-criteria and multi-scale approach was used. Three independent error criteria (Nash, error on volume and error on peak flow) were calculated and combined using the Pareto technique. Then, a multi-scale approach was used to calibrate and validate the model for the eight water flow measurements. The application of MHYDAS on the extreme ten flood events of the last decade enables to identify the ditches where overbank flows occur and to calculate discharge at various points of the ditch network. Results show that for the extreme flood event, more than 45% of surface runoff occur due to overbank flow. Discussion shows that

  18. Modeling of debris flow depositional patterns according to the catchment and sediment source area characteristics

    OpenAIRE

    2015-01-01

    A method to predict the most probable flow rheology in Alpine debris flows is presented. The methods classifies outcropping rock masses in catchments on the basis of the type of resulting unconsolidated deposits. The grain size distribution of the debris material and the depositional style of past debris flow events are related to the dominant flow processes: viscoplastic and frictional/collisional. Three catchments in the upper Susa Valley (Western Alps), characterized by different lithologi...

  19. Adaptation of the HBV model for the study of drought propagation in European catchments

    Science.gov (United States)

    van Loon, A. F.; van Lanen, H. A. J.; Seibert, J.; Torfs, P. J. J. F.

    2009-04-01

    Drought propagation is the conversion of a meteorological drought signal into a hydrological drought (e.g. groundwater and streamflow) as it moves through the subsurface part of the hydrological cycle. The lag, attenuation and possibly pooling of parts of the signal are dependent on climate and catchment characteristics. The understanding of processes underlying drought propagation is still very limited. Our aim is to study these processes in small catchments across Europe with different climate conditions and physical structures (e.g. hard rock, porous rock, flat areas, steep slopes, snow, lakes). As measurements of soil moisture and groundwater storage are normally scarce, simulation of these variables using a lumped hydrological model is needed. However, although a simple model is preferable, many conceptual rainfall-runoff models are not suitable for this purpose because of their focus on fast reactions and therefore unrealistic black box approach of the soil moisture and groundwater system. We studied the applicability of the well-known semi-distributed rainfall-runoff model HBV for drought propagation research. The results show that HBV reproduces observed discharges fairly well. However, in simulating groundwater storage in dry periods, HBV has some conceptual weaknesses: 1) surface runoff is approximated by a quick flow component through the upper groundwater box; 2) the storage in the upper groundwater box has no upper limit; 3) lakes are simulated as part of the lower groundwater box; 4) the percolation from the upper to the lower groundwater box is not continuous, but either zero or constant. So, adaptation of the HBV model structure was needed to be able to simulate realistic groundwater storage in dry periods. The HBV Light model (Seibert et al., 2000) was used as basis for this work. As the snow and soil routines of this model have proven their value in previous (drought) studies, these routines are left unchanged. The lower part of HBV Light, the

  20. Uncertainty assessment of a dominant-process catchment model of dissolved phosphorus transfer

    Science.gov (United States)

    Dupas, Rémi; Salmon-Monviola, Jordy; Beven, Keith J.; Durand, Patrick; Haygarth, Philip M.; Hollaway, Michael J.; Gascuel-Odoux, Chantal

    2016-12-01

    We developed a parsimonious topography-based hydrologic model coupled with a soil biogeochemistry sub-model in order to improve understanding and prediction of soluble reactive phosphorus (SRP) transfer in agricultural headwater catchments. The model structure aims to capture the dominant hydrological and biogeochemical processes identified from multiscale observations in a research catchment (Kervidy-Naizin, 5 km2). Groundwater fluctuations, responsible for the connection of soil SRP production zones to the stream, were simulated with a fully distributed hydrologic model at 20 m resolution. The spatial variability of the soil phosphorus content and the temporal variability of soil moisture and temperature, which had previously been identified as key controlling factors of SRP solubilization in soils, were included as part of an empirical soil biogeochemistry sub-model. The modelling approach included an analysis of the information contained in the calibration data and propagation of uncertainty in model predictions using a generalized likelihood uncertainty estimation (GLUE) "limits of acceptability" framework. Overall, the model appeared to perform well given the uncertainty in the observational data, with a Nash-Sutcliffe efficiency on daily SRP loads between 0.1 and 0.8 for acceptable models. The role of hydrological connectivity via groundwater fluctuation and the role of increased SRP solubilization following dry/hot periods were captured well. We conclude that in the absence of near-continuous monitoring, the amount of information contained in the data is limited; hence, parsimonious models are more relevant than highly parameterized models. An analysis of uncertainty in the data is recommended for model calibration in order to provide reliable predictions.

  1. Runoff of small rocky headwater catchments: Field observations and hydrological modeling

    Science.gov (United States)

    Gregoretti, C.; Degetto, M.; Bernard, M.; Crucil, G.; Pimazzoni, A.; De Vido, G.; Berti, M.; Simoni, A.; Lanzoni, S.

    2016-10-01

    In dolomitic headwater catchments, intense rainstorms of short duration produce runoff discharges that often trigger debris flows on the scree slopes at the base of rock cliffs. In order to measure these discharges, we placed a measuring facility at the outlet (elevation 1770 m a.s.l.) of a small, rocky headwater catchment (area ˜0.032 km2, average slope ˜320%) located in the Venetian Dolomites (North Eastern Italian Alps). The facility consists of an approximately rectangular basin, ending with a sharp-crested weir. Six runoff events were recorded in the period 2011-2014, providing a unique opportunity for characterizing the hydrological response of the catchment. The measured hydrographs display impulsive shapes, with an abrupt raise up to the peak, followed by a rapidly decreasing tail, until a nearly constant plateau is eventually reached. This behavior can be simulated by means of a distributed hydrological model if the excess rainfall is determined accurately. We show that using the Soil Conservation Service Curve-Number (SCS-CN) method and assuming a constant routing velocity invariably results in an underestimated peak flow and a delayed peak time. A satisfactory prediction of the impulsive hydrograph shape, including peak value and timing, is obtained only by combining the SCS-CN procedure with a simplified version of the Horton equation, and simulating runoff routing along the channel network through a matched diffusivity kinematic wave model. The robustness of the proposed methodology is tested through a comparison between simulated and observed timings of runoff or debris flow occurrence in two neighboring alpine basins.

  2. Effects of spatial variability of precipitation for process-orientated hydrological modelling: results from two nested catchments

    Directory of Open Access Journals (Sweden)

    D. Tetzlaff

    2005-01-01

    Full Text Available The importance of considering the spatial distribution of rainfall for process-oriented hydrological modelling is well-known. However, the application of rainfall radar data to provide such detailed spatial resolution is still under debate. In this study the process-oriented TACD (Tracer Aided Catchment model, Distributed model had been used to investigate the effects of different spatially distributed rainfall input on simulated discharge and runoff components on an event base. TACD is fully distributed (50x50 m2 raster cells and was applied on an hourly base. As model input rainfall data from up to 11 ground stations and high resolution rainfall radar data from an operational C-band radar were used. For seven rainfall events the discharge simulations were investigated in further detail for the mountainous Brugga catchment (40 km2 and the St. Wilhelmer Talbach (15.2 km2 sub-basin, which are located in the Southern Black Forest Mountains, south-west Germany. The significance of spatial variable precipitation data was clearly demonstrated. Dependent on event characteristics, localized rain cells were occasionally poorly captured even by a dense ground station network, and this resulted in insufficient model results. For such events, radar data can provide better input data. However, an extensive data adjustment using ground station data is required. Therefore, a new method was developed that considers the rainfall intensity distribution. The use of the distributed catchment model allowed further insights into spatially variable impacts of different rainfall estimates. Impacts for discharge predictions are the largest in areas that are dominated by the production of fast runoff components. To conclude, the improvements for distributed runoff simulation using high resolution rainfall radar input data are strongly dependent on the investigated scale, the event characteristics, the existing

  3. The Wageningen Lowland Runoff Simulator (WALRUS): a lumped rainfall-runoff model for catchments with shallow groundwater

    Science.gov (United States)

    Brauer, C. C.; Teuling, A. J.; Torfs, P. J. J. F.; Uijlenhoet, R.

    2014-10-01

    We present the Wageningen Lowland Runoff Simulator (WALRUS), a novel rainfall-runoff model to fill the gap between complex, spatially distributed models which are often used in lowland catchments and simple, parametric (conceptual) models which have mostly been developed for sloping catchments. WALRUS explicitly accounts for processes that are important in lowland areas, notably (1) groundwater-unsaturated zone coupling, (2) wetness-dependent flow routes, (3) groundwater-surface water feedbacks and (4) seepage and surface water supply. WALRUS consists of a coupled groundwater-vadose zone reservoir, a quickflow reservoir and a surface water reservoir. WALRUS is suitable for operational use because it is computationally efficient and numerically stable (achieved with a flexible time step approach). In the open source model code default relations have been implemented, leaving only four parameters which require calibration. For research purposes, these defaults can easily be changed. Numerical experiments show that the implemented feedbacks have the desired effect on the system variables.

  4. Predicting hydrological signatures in ungauged catchments using spatial interpolation, index model, and rainfall-runoff modelling

    Science.gov (United States)

    Zhang, Yongqiang; Vaze, Jai; Chiew, Francis H. S.; Teng, Jin; Li, Ming

    2014-09-01

    Understanding a catchment's behaviours in terms of its underlying hydrological signatures is a fundamental task in surface water hydrology. It can help in water resource management, catchment classification, and prediction of runoff time series. This study investigated three approaches for predicting six hydrological signatures in southeastern Australia. These approaches were (1) spatial interpolation with three weighting schemes, (2) index model that estimates hydrological signatures using catchment characteristics, and (3) classical rainfall-runoff modelling. The six hydrological signatures fell into two categories: (1) long-term aggregated signatures - annual runoff coefficient, mean of log-transformed daily runoff, and zero flow ratio, and (2) signatures obtained from daily flow metrics - concavity index, seasonality ratio of runoff, and standard deviation of log-transformed daily flow. A total of 228 unregulated catchments were selected, with half the catchments randomly selected as gauged (or donors) for model building and the rest considered as ungauged (or receivers) to evaluate performance of the three approaches. The results showed that for two long-term aggregated signatures - the log-transformed daily runoff and runoff coefficient, the index model and rainfall-runoff modelling performed similarly, and were better than the spatial interpolation methods. For the zero flow ratio, the index model was best and the rainfall-runoff modelling performed worst. The other three signatures, derived from daily flow metrics and considered to be salient flow characteristics, were best predicted by the spatial interpolation methods of inverse distance weighting (IDW) and kriging. Comparison of flow duration curves predicted by the three approaches showed that the IDW method was best. The results found here provide guidelines for choosing the most appropriate approach for predicting hydrological behaviours at large scales.

  5. Integration of Volterra model with artificial neural networks for rainfall-runoff simulation in forested catchment of northern Iran

    Science.gov (United States)

    Kashani, Mahsa H.; Ghorbani, Mohammad Ali; Dinpashoh, Yagob; Shahmorad, Sedaghat

    2016-09-01

    Rainfall-runoff simulation is an important task in water resources management. In this study, an integrated Volterra model with artificial neural networks (IVANN) was presented to simulate the rainfall-runoff process. The proposed integrated model includes the semi-distributed forms of the Volterra and ANN models which can explore spatial variation in rainfall-runoff process without requiring physical characteristic parameters of the catchments, while taking advantage of the potential of Volterra and ANNs models in nonlinear mapping. The IVANN model was developed using hourly rainfall and runoff data pertaining to thirteen storms to study short-term responses of a forest catchment in northern Iran; and its performance was compared with that of semi-distributed integrated ANN (IANN) model and lumped Volterra model. The Volterra model was applied as a nonlinear model (second-order Volterra (SOV) model) and solved using the ordinary least square (OLS) method. The models performance were evaluated and compared using five performance criteria namely coefficient of efficiency, root mean square error, error of total volume, relative error of peak discharge and error of time for peak to arrive. Results showed that the IVANN model performs well than the other semi-distributed and lumped models to simulate the rainfall-runoff process. Comparing to the integrated models, the lumped SOV model has lower precision to simulate the rainfall-runoff process.

  6. N fluxes in two nitrogen saturated forested catchments in Germany: dynamics and modelling with INCA

    Directory of Open Access Journals (Sweden)

    J.-J. Langusch

    2002-01-01

    Full Text Available The N cycle in forests of the temperate zone in Europe has been changed substantially by the impact of atmospheric N deposition. Here, the fluxes and concentrations of mineral N in throughfall, soil solution and runoff in two German catchments, receiving high N inputs are investigated to test the applicability of an Integrated Nitrogen Model for European Catchments (INCA to small forested catchments. The Lehstenbach catchment (419 ha is located in the German Fichtelgebirge (NO Bavaria, 690-871 m asl. and is stocked with Norway spruce (Picea abies (L. Karst. of different ages. The Steinkreuz catchment (55 ha with European beech (Fagus sylvatica L. as the dominant tree species is located in the Steigerwald (NW Bavaria, 400-460 m asl.. The mean annual N fluxes with throughfall were slightly higher at the Lehstenbach (24.6 kg N ha-1 than at the Steinkreuz (20.4 kg N ha-1. In both catchments the N fluxes in the soil are dominated by NO3. At Lehstenbach, the N output with seepage at 90 cm soil depth was similar to the N flux with throughfall. At Steinkreuz more than 50 % of the N deposited was retained in the upper soil horizons. In both catchments, the NO3 fluxes with runoff were lower than those with seepage. The average annual NO3 concentrations in runoff in both catchments were between 0.7 to 1.4 mg NO3-N L-1 and no temporal trend was observed. The N budgets at the catchment scale indicated similar amounts of N retention (Lehstenbach: 19 kg N ha-1yr-1 ; Steinkreuz: 17 kg N ha-1yr-1. The parameter settings of the INCA model were simplified to reduce the model complexity. In both catchments, the NO3 concentrations and fluxes in runoff were matched well by the model. The seasonal patterns with lower NO3 runoff concentrations in summer at the Lehstenbach catchment were replicated. INCA underestimated the increased N3 concentrations during short periods of rewetting in late autumn at the Steinkreuz catchment. The model will be a helpful tool for the

  7. A comparison of predictive soil-carbon models across multiple spatio-temporal catchment scales.

    Science.gov (United States)

    Hancock, G. R.; Kunkel, V.; Wells, T.

    2014-12-01

    Soil's potential as a carbon sink for atmospheric CO2 has been widely discussed. Studies of soil organic carbon (SOC) controls, and the subsequent models derived from their findings, have focussed mainly on North American and European regions, and more recently, in regions such as China. In Australia, agricultural practices have led to losses in SOC. This implies that Australian soils have a large potential for increases in SOC. Building on previous work, here we examine the spatial and temporal variation in soil organic carbon (SOC) and its controlling factors controls across a large catchment of approximately 600 km2 in the Upper Hunter Valley, New South Wales, Australia, using data collected from two sampling campaigns, (April 2006 and June-July 2014). Remote sensing using Landsat (30m) and MODIS (250m) NDVI was used to determine if catchment SOC could be predicted using both low and high resolution remote sensing . Relationships between SOC and elevation, aboveground biomass (as represented by NDVI), topographic wetness index (TWI), and incident solar radiation as a surrogate for soil temperature were compared. Initial results demonstrate that higher spatio-temporal resolution may not be necessary for predicting SOC at larger scales. The relationship between SOC and the environmental tracer 137-Cesium as a surrogate for the loss of SOC by erosion also suggests that sediment transport and deposition influences the distribution of SOC. A model developed for the site suggests that simple linear relationships between vegetation, climate and sediment transport could improve SOC predictions.

  8. Learning outcomes from participatory modelling: A case study in the Tamar catchment, UK

    Science.gov (United States)

    Krueger, Tobias; Inman, Alex; Chilvers, Jason

    2014-05-01

    Strong arguments for participatory modelling in hydrology can be made on substantive, instrumental and normative grounds. These arguments have led to increasingly diverse groups of stakeholders (here anyone affecting or affected by an issue) getting involved in hydrological research and the management of water resources. In fact, participation has become a requirement of many research grants, programmes, plans and policies. However, evidence of beneficial outcomes of participation as suggested by the arguments is difficult to generate and therefore rare. This is because outcomes are diverse, distributed, often tacit, and take time to emerge. In this paper we present results from applying an evaluation framework focussed on learning outcomes (Krueger et al., 2012) to a participatory modelling process within the Tamar catchment pilot of the UK government's new Catchment Based Approach of managing water resources. The process was run as a series of workshops with email and telephone conversations in between. The outputs were models of sediment and Faecal Coliform transfers from land to water and down to the catchment outlet, mitigated by sewage treatment options, land use, livestock densities and farm management practices. The learning outcomes were assessed through semi-structured interviews with the participants. The results indicate a lack of fairness and some competence issues of the participatory modelling process. Nevertheless, salience, credibility and legitimacy of the models were judged positively by the majority of participants, and some substantive and instrumental benefits of participatory modelling theory could be confirmed, specifically input of better data and increased buy-in and ownership from the participants, respectively. Instrumental learning by the participants was high and facilitated through the models as well as the group setting. Communicative learning by the participants was mixed, with people increasingly appreciating the views of others

  9. An INCA model for pathogens in rivers and catchments: Model structure, sensitivity analysis and application to the River Thames catchment, UK.

    Science.gov (United States)

    Whitehead, P G; Leckie, H; Rankinen, K; Butterfield, D; Futter, M N; Bussi, G

    2016-12-01

    Pathogens are an ongoing issue for catchment water management and quantifying their transport, loss and potential impacts at key locations, such as water abstractions for public supply and bathing sites, is an important aspect of catchment and coastal management. The Integrated Catchment Model (INCA) has been adapted to model the sources and sinks of pathogens and to capture the dominant dynamics and processes controlling pathogens in catchments. The model simulates the stores of pathogens in soils, sediments, rivers and groundwaters and can account for diffuse inputs of pathogens from agriculture, urban areas or atmospheric deposition. The model also allows for point source discharges from intensive livestock units or from sewage treatment works or any industrial input to river systems. Model equations are presented and the new pathogens model has been applied to the River Thames in order to assess total coliform (TC) responses under current and projected future land use. A Monte Carlo sensitivity analysis indicates that the input coliform estimates from agricultural sources and decay rates are the crucial parameters controlling pathogen behaviour. Whilst there are a number of uncertainties associated with the model that should be accounted for, INCA-Pathogens potentially provides a useful tool to inform policy decisions and manage pathogen loading in river systems. Copyright © 2016. Published by Elsevier B.V.

  10. Hydrologic comparison between a lowland catchment (Kielstau, Germany and a mountainous catchment (XitaoXi, China using KIDS model in PCRaster

    Directory of Open Access Journals (Sweden)

    N. Fohrer

    2009-08-01

    Full Text Available The KIDS model (Kielstau Discharge Simulation model is a simple rainfall-runoff model developed originally for the Kielstau catchment. To extend its range of application we applied it to a completely different catchment, the XitaoXi catchment in China. Kielstau is a small (51 km2 lowland basin in Northern Germany, with large proportion of wetland area. And XitaoXi is a mesoscale (2271 km2 mountainous basin in the south of China. Both catchments differ greatly in size, topography, landuse, soil properties, and weather conditions. We compared two catchments in these features and stress on the analysis how the specific catchment characteristics could guide the adaptation of KIDS model and the parameter estimation for streamflow simulation. The Nash and Sutcliffe coefficient was 0.73 for Kielstau and 0.65 for XitaoXi. The results suggest that the application of KIDS model may require adjustments according to the specific physical background of the study basin.

  11. Modeling nonlinear responses of DOC transport in boreal catchments in Sweden

    Science.gov (United States)

    Kasurinen, Ville; Alfredsen, Knut; Ojala, Anne; Pumpanen, Jukka; Weyhenmeyer, Gesa A.; Futter, Martyn N.; Laudon, Hjalmar; Berninger, Frank

    2016-07-01

    Stream water dissolved organic carbon (DOC) concentrations display high spatial and temporal variation in boreal catchments. Understanding and predicting these patterns is a challenge with great implications for water quality projections and carbon balance estimates. Although several biogeochemical models have been used to estimate stream water DOC dynamics, model biases common during both rain and snow melt-driven events. The parsimonious DOC-model, K-DOC, with 10 calibrated parameters, uses a nonlinear discharge and catchment water storage relationship including soil temperature dependencies of DOC release and consumption. K-DOC was used to estimate the stream water DOC concentrations over 5 years for eighteen nested boreal catchments having total area of 68 km2 (varying from 0.04 to 67.9 km2). The model successfully simulated DOC concentrations during base flow conditions, as well as, hydrological events in catchments dominated by organic and mineral soils reaching NSEs from 0.46 to 0.76. Our semimechanistic model was parsimonious enough to have all parameters estimated using statistical methods. We did not find any clear differences between forest and mire-dominated catchments that could be explained by soil type or tree species composition. However, parameters controlling slow release and consumption of DOC from soil water behaved differently for small headwater catchments (less than 2 km2) than for those that integrate larger areas of different ecosystem types (10-68 km2). Our results emphasize that it is important to account for nonlinear dependencies of both, soil temperature, and catchment water storage, when simulating DOC dynamics of boreal catchments.

  12. Effects of distributed and centralized stormwater best management practices and land cover on urban stream hydrology at the catchment scale

    Science.gov (United States)

    Loperfido, John V.; Noe, Gregory B.; Jarnagin, S. Taylor; Hogan, Dianna M.

    2014-01-01

    Urban stormwater runoff remains an important issue that causes local and regional-scale water quantity and quality issues. Stormwater best management practices (BMPs) have been widely used to mitigate runoff issues, traditionally in a centralized manner; however, problems associated with urban hydrology have remained. An emerging trend is implementation of BMPs in a distributed manner (multi-BMP treatment trains located on the landscape and integrated with urban design), but little catchment-scale performance of these systems have been reported to date. Here, stream hydrologic data (March, 2011–September, 2012) are evaluated in four catchments located in the Chesapeake Bay watershed: one utilizing distributed stormwater BMPs, two utilizing centralized stormwater BMPs, and a forested catchment serving as a reference. Among urban catchments with similar land cover, geology and BMP design standards (i.e. 100-year event), but contrasting placement of stormwater BMPs, distributed BMPs resulted in: significantly greater estimated baseflow, a higher minimum precipitation threshold for stream response and maximum discharge increases, better maximum discharge control for small precipitation events, and reduced runoff volume during an extreme (1000-year) precipitation event compared to centralized BMPs. For all catchments, greater forest land cover and less impervious cover appeared to be more important drivers than stormwater BMP spatial pattern, and caused lower total, stormflow, and baseflow runoff volume; lower maximum discharge during typical precipitation events; and lower runoff volume during an extreme precipitation event. Analysis of hydrologic field data in this study suggests that both the spatial distribution of stormwater BMPs and land cover are important for management of urban stormwater runoff. In particular, catchment-wide application of distributed BMPs improved stream hydrology compared to centralized BMPs, but not enough to fully replicate forested

  13. Effects of distributed and centralized stormwater best management practices and land cover on urban stream hydrology at the catchment scale

    Science.gov (United States)

    Loperfido, J. V.; Noe, Gregory B.; Jarnagin, S. Taylor; Hogan, Dianna M.

    2014-11-01

    Urban stormwater runoff remains an important issue that causes local and regional-scale water quantity and quality issues. Stormwater best management practices (BMPs) have been widely used to mitigate runoff issues, traditionally in a centralized manner; however, problems associated with urban hydrology have remained. An emerging trend is implementation of BMPs in a distributed manner (multi-BMP treatment trains located on the landscape and integrated with urban design), but little catchment-scale performance of these systems have been reported to date. Here, stream hydrologic data (March, 2011-September, 2012) are evaluated in four catchments located in the Chesapeake Bay watershed: one utilizing distributed stormwater BMPs, two utilizing centralized stormwater BMPs, and a forested catchment serving as a reference. Among urban catchments with similar land cover, geology and BMP design standards (i.e. 100-year event), but contrasting placement of stormwater BMPs, distributed BMPs resulted in: significantly greater estimated baseflow, a higher minimum precipitation threshold for stream response and maximum discharge increases, better maximum discharge control for small precipitation events, and reduced runoff volume during an extreme (1000-year) precipitation event compared to centralized BMPs. For all catchments, greater forest land cover and less impervious cover appeared to be more important drivers than stormwater BMP spatial pattern, and caused lower total, stormflow, and baseflow runoff volume; lower maximum discharge during typical precipitation events; and lower runoff volume during an extreme precipitation event. Analysis of hydrologic field data in this study suggests that both the spatial distribution of stormwater BMPs and land cover are important for management of urban stormwater runoff. In particular, catchment-wide application of distributed BMPs improved stream hydrology compared to centralized BMPs, but not enough to fully replicate forested

  14. Dynamically Evolving Models for Dynamic Catchments: Application of the Locally Linear Dual EnKF to a Catchment with Land Use Change

    Science.gov (United States)

    Pathiraja, S. D.; Marshall, L. A.; Sharma, A.; Moradkhani, H.

    2015-12-01

    Catchments are dynamic, constantly undergoing change be it naturally or due to anthropogenic influences. Changes in land surface conditions such as disturbance due to bushfire or erosion, urbanisation, deforestation or afforestation will affect a catchment's hydrologic regime. Models calibrated to pre-change conditions will lead to biased streamflow predictions, unless the change is explicitly accounted for in the model. A modelling methodology that is capable of adjusting its form (for instance, through time varying parameters) as catchments undergo change is therefore needed. We developed a framework for automatically and objectively detecting time variations in model parameters using Data Assimilation. The so called Locally Linear Dual EnKF was previously tested against a range of synthetic case studies and shown to reproduce known temporal variations from assimilating streamflow observations only. In this study, we apply the Locally Linear Dual EnKF to the Wights and Salmon paired catchments in Western Australia. Both were initially forested and monitored for a 3 year period, after which Wights was fully cleared whilst Salmon remained unchanged. The lumped conceptual hydrologic model (PDM) was calibrated over the stationary period and the optimal parameterisation used to initialise the Locally Linear Dual EnKF. Resultant parameter trajectories for the Salmon catchment were relatively stationary, whilst parameters for the Wights catchment were automatically adjusted to produce greater flood peaks, sooner after rainfall, consistent with observations. A significant improvement in both streamflow prediction and catchment soil moisture was obtained with the Locally Linear Dual EnKF, compared to the time invariant parameter case. This application has demonstrated the usefulness of this framework for improving predictions in rapidly changing catchments.

  15. Storage dynamics in hydropedological units control hillslope connectivity, runoff generation, and the evolution of catchment transit time distributions.

    Science.gov (United States)

    Tetzlaff, D; Birkel, C; Dick, J; Geris, J; Soulsby, C

    2014-02-01

    We examined the storage dynamics and isotopic composition of soil water over 12 months in three hydropedological units in order to understand runoff generation in a montane catchment. The units form classic catena sequences from freely draining podzols on steep upper hillslopes through peaty gleys in shallower lower slopes to deeper peats in the riparian zone. The peaty gleys and peats remained saturated throughout the year, while the podzols showed distinct wetting and drying cycles. In this region, most precipitation events are 80% of flow, even in large events, reflecting the displacement of water from the riparian soils that has been stored in the catchment for >2 years. These riparian areas are the key zone where different source waters mix. Our study is novel in showing that they act as "isostats," not only regulating the isotopic composition of stream water, but also integrating the transit time distribution for the catchment. Hillslope connectivity is controlled by small storage changes in soil unitsDifferent catchment source waters mix in large riparian wetland storageIsotopes show riparian wetlands set the catchment transit time distribution.

  16. Remote sensing Penman-Monteith model to estimate catchment evapotranspiration considering the vegetation diversity

    Science.gov (United States)

    Li, Fawen; Cao, Runxiang; Zhao, Yong; Mu, Dongjing; Fu, Changfeng; Ping, Feng

    2017-01-01

    A new method for calculating evaporation is proposed, using the Penman-Monteith (P-M) model with remote sensing. This paper achieved the effective estimation to daily evapotranspiration in the Ziya river catchment by using the P-M model based on MODIS remote sensing leaf area index and respectively estimated plant transpiration and soil evaporation by using coefficient of soil evaporation. This model divided catchment into seven different sub-regions which are prairie, meadow, grass, shrub, broad-leaved forest, cultivated vegetation, and coniferous forest through thoroughly considering the vegetation diversity. Furthermore, optimizing and calibrating parameters based on each sub-region and analyzing spatio-temporal variation rules of the model main parameters which are coefficient of soil evaporation f and maximum stomatal conductance g sx . The results indicate that f and g sx calibrated by model are basically consistent with measured data and have obvious spatio-temporal distribution characteristics. The monthly average evapotranspiration value of simulation is 37.96 mm/mon which is close to the measured value with 33.66 mm/mon and the relative error of simulation results in each subregion are within 11 %, which illustrates that simulated values and measured values fit well and the precision of model is high. In addition, plant transpiration and soil evaporation account for about 84.64 and 15.36 % respectively in total evapotranspiration, which means the difference between values of them is large. What is more, this model can effectively estimate the green water resources in basin and provide effective technological support for water resources estimation.

  17. Observational techniques for constraining hydraulic and hydrologic models for use in catchment scale flood impact assessment

    Science.gov (United States)

    Owen, Gareth; Wilkinson, Mark; Nicholson, Alex; Quinn, Paul; O'Donnell, Greg

    2015-04-01

    There is an increase in the use of Natural Flood Management (NFM) schemes to tackle excessive runoff in rural catchments, but direct evidence of their functioning during extreme events is often lacking. With the availability of low cost sensors, a dense nested monitoring network can be established to provide near continuous optical and physical observations of hydrological processes. This paper will discuss findings for a number of catchments in the North of England where land use management and NFM have been implemented for flood risk reduction; and show how these observations have been used to inform both a hydraulic and a rainfall-runoff model. The value of observations in understanding how measures function is of fundamental importance and is becoming increasingly viable and affordable. Open source electronic platforms such as Arduino and Raspberry Pi are being used with cheap sensors to perform these tasks. For example, a level gauge has been developed for approximately €110 and cameras capable of capturing still or moving pictures are available for approximately €120; these are being used to better understand the behaviour of NFM features such as ponds and woody debris. There is potential for networks of these instruments to be configured and data collected through Wi-Fi or other wireless networks. The potential to expand informative networks of data that can constrain models is now possible. The functioning of small scale runoff attenuation features, such as offline ponds, has been demonstrated at the local scale. Specifically, through the measurement of both instream and in-pond water levels, it has been possible to calculate the impact of storing/attenuating flood flows on the adjacent river flow. This information has been encapsulated in a hydraulic model that allows the extrapolation of impacts to the larger catchment scale, contributing to understanding of the scalability of such features. Using a dense network of level gauges located along the main

  18. Modelling Landscape Dynamics in a Highland Mediterranean Catchment: Establishing the impact of Climate Variation and Human Activity

    Science.gov (United States)

    van Beek, L. P. H.; Feiken, H.; van Asch, T. W. J.; Bierkens, M. F. P.

    2012-04-01

    The close link between human occupancy and the Mediterranean landscape has long been recognized. Through the exploitation of the various but fragmented resources that these landscapes have to offer, man has been able to secure a living. However, these activities are often marginal and small shifts in population pressure, corresponding land use patterns or climatic variability can have large consequences on the redistribution of water and sediment in these areas. The meso-scale landscape dynamics model, CALEROS, has been developed to simulate the interactions between climate, soil production and erosion, vegetation and land use on geomorphological to human time scales in Mediterranean environments. Starting from an initial landscape consisting of a DTM, soil distribution and underlying lithology, the landscape is free to develop in response to the imposed climate variability and seismicity. In addition to changes in soil distribution and bedrock lowering, this includes the establishment of vegetation as conditioned by a selection of plant functional types and, optionally, population and land use dynamics as conditioned by land use scenarios specifying technological and dietary constraints for different periods. As such CALEROS is well-suited to investigate the relative impacts of climate, land cover and human activities on the hydrological catchment response and the associated sediment fluxes due to soil erosion and mass movements. Within the context of a geo-archeological study on the conservation potential of settlement history in the Contrada Maddalena (~14km2, Calabria, Italy), we apply CALEROS to investigate the relative contributions of climate and man from Neolithic times onwards (5000 BP-present). Model results allow to establish when human impacts become significant over natural variations and to discern shifts in catchment functioning as a result of sudden or climatic variations (e.g., Little Ice Age) as reflected in vegetation patterns and water and

  19. Modelling (flash) floods in a Dutch lowland catchment

    NARCIS (Netherlands)

    Brauer, C.C.; Teuling, A.J.; Overeem, A.; Velde, Y. van der; Hazenberg, P.; Warmerdam, P.M.M.; Kloosterman, P.; Uijlenhoet, R.

    2012-01-01

    On 26 August 2010 the eastern part of The Netherlands and the bordering part of Germany were struck by a series of rainfall events.We investigated the unprecedented flash flood triggered by this exceptionally heavy rainfall event (return period > 1000 years) in the 6.5 km2 Hupsel Brook catchment, wh

  20. Usefulness of four hydrological models in simulating high-resolution discharge dynamics of a catchment adjacent to a road

    Science.gov (United States)

    Kalantari, Z.; Jansson, P.-E.; Stolte, J.; Folkeson, L.; French, H. K.; Sassner, M.

    2012-04-01

    Four hydrological models (LISEM, MIKE SHE, CoupModel and HBV) were compared with respect to their capability to predict peak flow in a small catchment upstream of a road in SE Norway on an hourly basis. All four models were calibrated using hourly observed streamflow. Simulated and observed discharge generated during three types of hydrological situations characteristic of winter/spring conditions causing overland flow were considered: snowmelt, partially frozen soil and heavy rain events. Using parameter sets optimised for winter/spring conditions, flows simulated by HBV coupled with CoupModel were comparable to measured discharge from the catchment in corresponding periods. However, this combination was best when all the parameters were calibrated in HBV. For ungauged basins with no real-time monitoring of discharge and when the spatial distribution is important, MIKE SHE may be more suitable than the other models, but the lack of detailed input data and the uncertainty in physical parameters should be considered. LISEM is potentially capable of calculating runoff from small catchments during winter/spring but requires better description of snowmelt, infiltration into frozen layers and tile drainage. From a practical road maintenance perspective, the usefulness and accuracy of a model depends on its ability to represent site-specific processes, data availability and calibration requirements.

  1. Usefulness of four hydrological models in simulating high-resolution discharge dynamics of a catchment adjacent to a road

    Directory of Open Access Journals (Sweden)

    Z. Kalantari

    2012-04-01

    Full Text Available Four hydrological models (LISEM, MIKE SHE, CoupModel and HBV were compared with respect to their capability to predict peak flow in a small catchment upstream of a road in SE Norway on an hourly basis. All four models were calibrated using hourly observed streamflow. Simulated and observed discharge generated during three types of hydrological situations characteristic of winter/spring conditions causing overland flow were considered: snowmelt, partially frozen soil and heavy rain events. Using parameter sets optimised for winter/spring conditions, flows simulated by HBV coupled with CoupModel were comparable to measured discharge from the catchment in corresponding periods. However, this combination was best when all the parameters were calibrated in HBV. For ungauged basins with no real-time monitoring of discharge and when the spatial distribution is important, MIKE SHE may be more suitable than the other models, but the lack of detailed input data and the uncertainty in physical parameters should be considered. LISEM is potentially capable of calculating runoff from small catchments during winter/spring but requires better description of snowmelt, infiltration into frozen layers and tile drainage. From a practical road maintenance perspective, the usefulness and accuracy of a model depends on its ability to represent site-specific processes, data availability and calibration requirements.

  2. A comparative analysis of projected impacts of climate change on river runoff from global and catchment-scale hydrological models

    Directory of Open Access Journals (Sweden)

    S. N. Gosling

    2011-01-01

    Full Text Available We present a comparative analysis of projected impacts of climate change on river runoff from two types of distributed hydrological model, a global hydrological model (GHM and catchment-scale hydrological models (CHM. Analyses are conducted for six catchments that are global in coverage and feature strong contrasts in spatial scale as well as climatic and developmental conditions. These include the Liard (Canada, Mekong (SE Asia, Okavango (SW Africa, Rio Grande (Brazil, Xiangxi (China and Harper's Brook (UK. A single GHM (Mac-PDM.09 is applied to all catchments whilst different CHMs are applied for each catchment. The CHMs include SLURP v. 12.2 (Liard, SLURP v. 12.7 (Mekong, Pitman (Okavango, MGB-IPH (Rio Grande, AV-SWAT-X 2005 (Xiangxi and Cat-PDM (Harper's Brook. The CHMs typically simulate water resource impacts based on a more explicit representation of catchment water resources than that available from the GHM and the CHMs include river routing, whereas the GHM does not. Simulations of mean annual runoff, mean monthly runoff and high (Q5 and low (Q95 monthly runoff under baseline (1961–1990 and climate change scenarios are presented. We compare the simulated runoff response of each hydrological model to (1 prescribed increases in global-mean air temperature of 1.0, 2.0, 3.0, 4.0, 5.0 and 6.0 °C relative to baseline from the UKMO HadCM3 Global Climate Model (GCM to explore response to different amounts of climate forcing, and (2 a prescribed increase in global-mean air temperature of 2.0 °C relative to baseline for seven GCMs to explore response to climate model structural uncertainty.

    We find that the differences in projected changes of mean annual runoff between the two types of hydrological model can be substantial for a given GCM (e.g. an absolute GHM-CHM difference in mean annual runoff percentage change for UKMO HadCM3 2 °C warming of up to 25%, and they are generally larger for indicators of high and low monthly runoff

  3. Monitoring and modeling the snowpack dynamics in the Arve upper catchment for hydrological purposes

    Science.gov (United States)

    Revuelto, Jesús; Lecourt, Grégoire; Charrois, Luc; Lafaysse, Matthieu; Condom, Thomas; Dumont, Marie; Morin, Samuel; Rabatel, Antoine; Six, Delphine; Vionnet, Vincent; Zin, Isabella

    2016-04-01

    Snow accumulation and its evolution over space and time have major importance for the hydrological cycle, especially at high elevations. The characteristics of mountain valley, such as a wide altitudinal range, large glaciated areas, snow presence all along the year; when combined with specific meteorological conditions like heat waves or extreme rain events, may originate dramatic flash floods, potentially affecting populated areas. Thus, improving snowpack monitoring and forecasting tools are needed to strength the reliability of warning systems. Nowadays, accurately characterising and simulating snowpack evolution over large areas still represents a challenge, and uncertainties arise. The study presented here is focused in analysing two different types of simulation of the snowpack dynamics, performed with different discretization approaches, distributed or semi-distributed, and how these could move forward assimilating remote sensing data from satellites. The considered study area is the Arve catchment at Chamonix, in the French Northern Alps. This valley has the previously mentioned characteristics: it comprises a large elevation range (between 1000 to 4800m asl, with large areas above 2000m asl) and about 32% of its extension (200km2) is glaciated. Thus, the hydrological cycle of this area is highly dependent on the snowpack and the glacier melt dynamics. The snowpack of the Arve catchment has been simulated from 1990 to 2014 with the Crocus model integrated within the SURFEX modelling platform. The input fields are provided by the SAFRAN reanalysis system and the simulations have been performed with both a semi-distributed (classifying terrain by aspect, elevation, slope and land use/land cover) and a distributed (250m spatial resolution grid cells over the study area) approaches. The use of these two approaches using the same snowpack model and same meteorological forcing, enables their comparison in terms of river discharges at several outlets; showing the

  4. Novel MixSIAR fingerprint model implementation in a Mediterranean mountain catchment

    Science.gov (United States)

    Lizaga, Ivan; Gaspar, Leticia; Blake, William; Palazón, Leticia; Quijano, Laura; Navas, Ana

    2017-04-01

    Increased sediment erosion levels can lead to degraded water and food quality, reduced aquatic biodiversity, decrease reservoir capacity and restrict recreational usage but determining soil redistribution and sediment budgets in watersheds is often challenging. One of the methods for making such determinations applies sediment fingerprinting methods by using sediment properties. The fingerprinting procedure tests a range of source material tracer properties to select a subset that can discriminate between the different potential sediment sources. The present study aims to test the feasibility of geochemical and radioisotopic fingerprint properties to apportion sediment sources within the Barués catchment. For this purpose, the new MixSIAR unmixing model was implemented as statistical tool. A total of 98 soil samples from different land cover sources (Mediterranean forest, pine forest scrubland, agricultural and subsoil) were collected in the Barués catchment (23 km2). This new approach divides the catchment into six different sub-catchments to evaluate how the sediment provenance varies along the river and the percentage of its sources and not only the contribution at the end. For this purpose, target sediments were collected at the end of each sub-catchment to introduce the variation along the entire catchment. Geochemistry and radioisotopic activity were analyzed for each sample and introduced as input parameters in the model. Percentage values from the five sources were different along the different subcatchments and the variations of all of them are summarized at the final target sample located at the end of the catchment. This work represents a good approximation to the fine sediment provenance in Mediterranean agricultural catchments and has the potential to be used for water resource control and future soil management. Identifying sediment contribution from different land uses offers considerable potential to prevent environmental degradation and the

  5. Pattern of Landslide Distribution Reflects Degree of Hillslope Adjustment in a Waipaoa River Catchment, New Zealand

    Science.gov (United States)

    Cerovski-Darriau, C.; Roering, J. J.

    2014-12-01

    Using landslide morphology to determine the state of hillslope transience provides a diagnostic tool to identify the extent of landscape adjustment. Here we test for a temporal and spatial progression of landslides reflecting the degree of adjustment for a Waipaoa River catchment (North Island, New Zealand). Following the shift to a warmer, wetter climate after the Last Glacial Maximum (LGM) (~18 ka), the Waipaoa River rapidly incised up to 120 m, leaving perched, low-relief hillslopes unadjusted to that base level fall. In the 16 km2 study catchment—principally comprised of weak mélange—pervasive post-LGM landslides responded to >50 m of fluvial incision by sculpting and denuding >99% of the catchment, but adjustment is not yet complete. Starting ~150 years ago, European settlers deforested ~95% of the landscape, which triggered a sharp increase in hillslope erosion as widespread earthflow complexes and gully systems reactivated and/or expanded in the weak lithology with the loss of vegetation cover. Most of the remaining relict (≥18 ka) landforms are confined to the upper watershed, upholding the proposed upstream progression of hillslope adjustment. Based on previous tephrochronology and surface roughness data, present-day earthflows follow this pattern of younging upstream. Here we analyze the size, location, and distribution of ~500 earthflows (mapped from 2010 lidar and orthophotos) to determine if there is a spatial progression of earthflows reflective of hillslope adjustment and correlated to the previously identified temporal progression. Morphologic evidence from this study indicates the younger earthflows in the upper watershed have smaller areas (6000 ± 600 m2 (mean ± s.e.)), a more elongate aspect ratio (AR=3.6 ± 1.6 (mean ± s.d.)), and are generally (>50%) deposited in axial gullies, whereas downstream earthflows are larger (20000 ± 9000 m2), statistically less elongate (AR=2.3 ± 0.9), and more frequently coupled with the main channel

  6. Combining experimentalist knowledge with modelling approaches to evaluate a controlled herbicide application experiment in an agricultural headwater catchment

    Science.gov (United States)

    Ammann, Lorenz; Fenicia, Fabrizio; Doppler, Tobias; Reichert, Peter; Stamm, Christian

    2017-04-01

    Although only a small fraction of the herbicide mass sprayed on agricultural fields reaches the stream in usual conditions, concentrations in streams may reach levels proven to affect organisms. Therefore, diffuse pollution of water bodies by herbicides in catchments dominated by agricultural land-use is a major concern. The process of herbicide wash off has been studied through experiments at lab and field scales. Fewer studies are available at the scales of small catchments and larger watersheds, as the lack of spatial measurements at these scales hinders model parameterization and evaluation. Even fewer studies make explicit use of the combined knowledge of experimentalists and modellers. As a result, the dynamics and interactions of processes responsible for herbicide mobilization and transport at the catchment scale are insufficiently understood. In this work, we integrate preexisting experimentalist knowledge aquired in a large controlled herbicide application experiment into the model development process. The experimental site was a small (1.2 km2) agricultural catchment with subdued topography (423 to 473 m a.s.l.), typical for the Swiss Plateau. The experiment consisted of an application of multiple herbicides, distributed in-stream concentration measurements at high temporal resolution as well as soil and ponding water samples. The measurements revealed considerable spatio-temporal variation in herbicide loss rates. The objective of our study is to better understand the processes that caused this variation. In an iterative dialogue between modellers and experimentalists, we constructed a simple hydrological model structure with multiple reservoirs, considering degradation and sorption of herbicides. Spatial heterogeneity was accounted for through Hydrological Response Units (HRUs). Different model structures were used for dinstinct HRUs to account for spatial variability in the perceived dominant processes. Some parameters were linked between HRUs to

  7. Characterization of process-oriented hydrologic model behavior with temporal sensitivity analysis for flash floods in Mediterranean catchments

    Directory of Open Access Journals (Sweden)

    P. A. Garambois

    2013-06-01

    Full Text Available This paper presents a detailed analysis of 10 flash flood events in the Mediterranean region using the distributed hydrological model MARINE. Characterizing catchment response during flash flood events may provide new and valuable insight into the dynamics involved for extreme catchment response and their dependency on physiographic properties and flood severity. The main objective of this study is to analyze flash-flood-dedicated hydrologic model sensitivity with a new approach in hydrology, allowing model outputs variance decomposition for temporal patterns of parameter sensitivity analysis. Such approaches enable ranking of uncertainty sources for nonlinear and nonmonotonic mappings with a low computational cost. Hydrologic model and sensitivity analysis are used as learning tools on a large flash flood dataset. With Nash performances above 0.73 on average for this extended set of 10 validation events, the five sensitive parameters of MARINE process-oriented distributed model are analyzed. This contribution shows that soil depth explains more than 80% of model output variance when most hydrographs are peaking. Moreover, the lateral subsurface transfer is responsible for 80% of model variance for some catchment-flood events' hydrographs during slow-declining limbs. The unexplained variance of model output representing interactions between parameters reveals to be very low during modeled flood peaks and informs that model-parsimonious parameterization is appropriate to tackle the problem of flash floods. Interactions observed after model initialization or rainfall intensity peaks incite to improve water partition representation between flow components and initialization itself. This paper gives a practical framework for application of this method to other models, landscapes and climatic conditions, potentially helping to improve processes understanding and representation.

  8. Characterization of physically based hydrologic model behaviour with temporal sensitivity analysis for flash floods in Mediterranean catchments

    Directory of Open Access Journals (Sweden)

    P. A. Garambois

    2013-01-01

    Full Text Available This paper presents a detailed analysis of 10 flash flood events in the Mediterranean region using the distributed hydrological model MARINE. Characterizing catchment's response during flash flood events may provide a new and valuable insight into the processes involved for extreme flood response and their dependency on catchment properties and flood severity. The main objective of this study is to analyze hydrologic model sensitivity in the case of flash floods with a new approach in hydrology, allowing model outputs variance decomposition for temporal patterns of parameter sensitivity analysis. Such approaches enable ranking of uncertainty sources for non-linear and non-monotonic mappings with a low computational cost. This study uses hydrologic model and sensitivity analysis as learning tools to derive temporal sensitivity analysis with a variance based method in the case of 10 flash floods that occurred in the French Pyrenees and Cévennes foothills. This constitutes a huge dataset given the scarcity of data about flash flood events. With Nash performances above 0.73 on average for this extended set of validation events, the five sensitive parameters of MARINE distributed physically based model are analyzed. This contribution shows that soil depth explains more than 80% of model output variance when most hydrographs are peaking. Moreover the lateral subsurface transfer is responsible for 80% of model variance for some catchment-flood events' hydrographs during slow declining limbs. The unexplained variance of model output representing interactions between parameters reveals to be very low during modeled flood peaks and informs that model parsimonious parameterization is appropriate to tackle the problem of flash floods. Interactions observed after model initialization or rainfall intensity peaks incite to improve water partition representation between flow components and initialization itself. This paper gives a practical framework for

  9. Ensemble flood simulation for a small dam catchment in Japan using 10 and 2 km resolution nonhydrostatic model rainfalls

    Science.gov (United States)

    Kobayashi, Kenichiro; Otsuka, Shigenori; Apip; Saito, Kazuo

    2016-08-01

    This paper presents a study on short-term ensemble flood forecasting specifically for small dam catchments in Japan. Numerical ensemble simulations of rainfall from the Japan Meteorological Agency nonhydrostatic model (JMA-NHM) are used as the input data to a rainfall-runoff model for predicting river discharge into a dam. The ensemble weather simulations use a conventional 10 km and a high-resolution 2 km spatial resolutions. A distributed rainfall-runoff model is constructed for the Kasahori dam catchment (approx. 70 km2) and applied with the ensemble rainfalls. The results show that the hourly maximum and cumulative catchment-average rainfalls of the 2 km resolution JMA-NHM ensemble simulation are more appropriate than the 10 km resolution rainfalls. All the simulated inflows based on the 2 and 10 km rainfalls become larger than the flood discharge of 140 m3 s-1, a threshold value for flood control. The inflows with the 10 km resolution ensemble rainfall are all considerably smaller than the observations, while at least one simulated discharge out of 11 ensemble members with the 2 km resolution rainfalls reproduces the first peak of the inflow at the Kasahori dam with similar amplitude to observations, although there are spatiotemporal lags between simulation and observation. To take positional lags into account of the ensemble discharge simulation, the rainfall distribution in each ensemble member is shifted so that the catchment-averaged cumulative rainfall of the Kasahori dam maximizes. The runoff simulation with the position-shifted rainfalls shows much better results than the original ensemble discharge simulations.

  10. Evaluating the hydrological component of the new catchment-scale sediment delivery model LAPSUS-D

    Science.gov (United States)

    Keesstra, S. D.; Temme, A. J. A. M.; Schoorl, J. M.; Visser, S. M.

    2014-05-01

    Physically-based, catchment scale sediment delivery models have become increasingly complex, sophisticated and are suitable for a diverse range of environmental contexts. However, in their attempts to best represent the physical processes of erosion and deposition, these models require large and detailed input datasets. When such data are unavailable, annual sediment yield models are relied upon. However, in this class of models, widely available data such as daily precipitation and discharge are disregarded resulting in a reduction in temporal accuracy. To fill this scientific and management gap, the landscape evolution model LAPSUS was adapted (LAPSUS-D) for a meso-scale catchment to model sediment yield on a daily resolution. The water balance component within the model enables the calibration of the model in terms of water discharge with measured daily discharge at the outlet. This methodology is especially important when modeling sediment yield from catchments which are ungaged catchments in terms of sediment, but where hydrological data are available. As the simulation of sediment yield was the main objective of the study, the calibration focused on peak discharge. The focus on peak discharge provides insight into the capability of the model to generate, route and deliver sediment at the outlet of a meso-scale catchment. LAPSUS-D has daily temporal resolution and requires a 10 to 30 m pixel size DEM, soil map, land-use map and daily hydrological records (precipitation and discharge). In this paper we present the first assessment of the hydrological model performance and an analysis of the sensitivity of the model to input parameters. Our study site is a 23-km2 catchment in Upper Nysa Szalona, southwest Poland with temperate climate.

  11. Assessing the benefit of snow data assimilation for runoff modeling in Alpine catchments

    Science.gov (United States)

    Griessinger, Nena; Seibert, Jan; Magnusson, Jan; Jonas, Tobias

    2016-09-01

    In Alpine catchments, snowmelt is often a major contribution to runoff. Therefore, modeling snow processes is important when concerned with flood or drought forecasting, reservoir operation and inland waterway management. In this study, we address the question of how sensitive hydrological models are to the representation of snow cover dynamics and whether the performance of a hydrological model can be enhanced by integrating data from a dedicated external snow monitoring system. As a framework for our tests we have used the hydrological model HBV (Hydrologiska Byråns Vattenbalansavdelning) in the version HBV-light, which has been applied in many hydrological studies and is also in use for operational purposes. While HBV originally follows a temperature-index approach with time-invariant calibrated degree-day factors to represent snowmelt, in this study the HBV model was modified to use snowmelt time series from an external and spatially distributed snow model as model input. The external snow model integrates three-dimensional sequential assimilation of snow monitoring data with a snowmelt model, which is also based on the temperature-index approach but uses a time-variant degree-day factor. The following three variations of this external snow model were applied: (a) the full model with assimilation of observational snow data from a dense monitoring network, (b) the same snow model but with data assimilation switched off and (c) a downgraded version of the same snow model representing snowmelt with a time-invariant degree-day factor. Model runs were conducted for 20 catchments at different elevations within Switzerland for 15 years. Our results show that at low and mid-elevations the performance of the runoff simulations did not vary considerably with the snow model version chosen. At higher elevations, however, best performance in terms of simulated runoff was obtained when using the snowmelt time series from the snow model, which utilized data assimilation

  12. Development of a coupled hydrological - hydrodynamic model for probabilistic catchment flood inundation modelling

    Science.gov (United States)

    Quinn, Niall; Freer, Jim; Coxon, Gemma; Dunne, Toby; Neal, Jeff; Bates, Paul; Sampson, Chris; Smith, Andy; Parkin, Geoff

    2017-04-01

    Computationally efficient flood inundation modelling systems capable of representing important hydrological and hydrodynamic flood generating processes over relatively large regions are vital for those interested in flood preparation, response, and real time forecasting. However, such systems are currently not readily available. This can be particularly important where flood predictions from intense rainfall are considered as the processes leading to flooding often involve localised, non-linear spatially connected hillslope-catchment responses. Therefore, this research introduces a novel hydrological-hydraulic modelling framework for the provision of probabilistic flood inundation predictions across catchment to regional scales that explicitly account for spatial variability in rainfall-runoff and routing processes. Approaches have been developed to automate the provision of required input datasets and estimate essential catchment characteristics from freely available, national datasets. This is an essential component of the framework as when making predictions over multiple catchments or at relatively large scales, and where data is often scarce, obtaining local information and manually incorporating it into the model quickly becomes infeasible. An extreme flooding event in the town of Morpeth, NE England, in 2008 was used as a first case study evaluation of the modelling framework introduced. The results demonstrated a high degree of prediction accuracy when comparing modelled and reconstructed event characteristics for the event, while the efficiency of the modelling approach used enabled the generation of relatively large ensembles of realisations from which uncertainty within the prediction may be represented. This research supports previous literature highlighting the importance of probabilistic forecasting, particularly during extreme events, which can be often be poorly characterised or even missed by deterministic predictions due to the inherent

  13. Evaluation of the JULES land surface model in simulating catchment hydrology in Southern Africa

    Directory of Open Access Journals (Sweden)

    N. C. MacKellar

    2013-08-01

    Full Text Available Land surface models (LSMs are advanced tools which can be used to estimate energy, water and biogeochemical exchanges at regional scales. The inclusion of a river flow routing module in an LSM allows for the simulation of river discharge from a catchment and offers an approach to evaluate the response of the system to variations in climate and land-use, which can provide useful information for regional water resource management. This study offers insight into some of the pragmatic considerations of applying an LSM over a regional domain in Southern Africa. The objectives are to identify key parameter sensitivities and investigate differences between two runoff production schemes in physically contrasted catchments. The Joint UK Land Environment Simulator (JULES LSM was configured for a domain covering Southern Africa at a 0.5° resolution. The model was forced with meteorological input from the WATCH Forcing Data for the period 1981–2001 and sensitivity to various model configurations and parameter settings were tested. Both the PDM and TOPMODEL sub-grid scale runoff generation schemes were tested for parameter sensitivities, with the evaluation focussing on simulated river discharge in sub-catchments of the Orange, Okavango and Zambezi rivers. It was found that three catchments respond differently to the model configurations and there is no single runoff parameterization scheme or parameter values that yield optimal results across all catchments. The PDM scheme performs well in the upper Orange catchment, but poorly in the Okavango and Zambezi, whereas TOPMODEL grossly underestimates discharge in the upper Orange and shows marked improvement over PDM for the Okavango and Zambezi. A major shortcoming of PDM is that it does not realistically represent subsurface runoff in the deep, porous soils typical of the Okavango and Zambezi headwaters. The dry-season discharge in these catchments is therefore not replicated by PDM. TOPMODEL, however

  14. A comparative analysis of projected impacts of climate change on river runoff from global and catchment-scale hydrological models

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    S. N. Gosling

    2010-09-01

    Full Text Available We present a comparative analysis of projected impacts of climate change on river runoff from two types of distributed hydrological model, a global hydrological model (GHM and catchment-scale hydrological models (CHM. Analyses are conducted for six catchments that are global in coverage and feature strong contrasts in spatial scale as well as climatic and developmental conditions. These include the Liard (Canada, Mekong (SE Asia, Okavango (SW Africa, Rio Grande (Brazil, Xiangxi (China and Harper's Brook (UK. A single GHM (Mac-PDM.09 is applied to all catchments whilst different CHMs are applied for each catchment. The CHMs include SLURP v. 12.2 (Liard, SLURP v. 12.7 (Mekong, Pitman (Okavango, MGB-IPH (Rio Grande, AV-SWAT-X 2005 (Xiangxi and Cat-PDM (Harper's Brook. Simulations of mean annual runoff, mean monthly runoff and high (Q5 and low (Q95 monthly runoff under baseline (1961–1990 and climate change scenarios are presented. We compare the simulated runoff response of each hydrological model to (1 prescribed increases in global-mean air temperature of 1.0, 2.0, 3.0, 4.0, 5.0 and 6.0 °C relative to baseline from the UKMO HadCM3 Global Climate Model (GCM to explore response to different amounts of climate forcing, and (2 a prescribed increase in global-mean air temperature of 2.0 °C relative to baseline for seven GCMs to explore response to climate model structural uncertainty.

    We find that the differences in projected changes of mean annual runoff between the two types of hydrological model can be substantial for a given GCM, and they are generally larger for indicators of high and low monthly runoff. However, they are relatively small in comparison to the range of projections across the seven GCMs. Hence, for the six catchments and seven GCMs we considered, climate model structural uncertainty is greater than the uncertainty associated with the type of hydrological model applied. Moreover, shifts in the seasonal cycle of runoff

  15. Modeling of hydrographs in torrent catchments by use of improved field data and adapted precipitation/runoff models

    Science.gov (United States)

    Kohl, B.; Klebinder, K.; Kirnbauer, R.; Markart, G.

    2009-04-01

    For description of runoff formation in alpine catchments still often simple runoff formulas are used on the one hand. On the other hand many precipitation / runoff models for assessment of runoff characteristics in mesoscale and microscale catchments require detailed input data and some are using algorithms which don't describe runoff processes "process-oriented". This especially applies to lumped and to some conceptual models. Fully distributed models mostly require enormous effort for determining serious catchment description parameters. As a first step into the direction of a time and cost sparing but still process based assessment of runoff development in alpine torrent catchments a two column-procedure has been developed at the BFW in cooperation with university scientists and in cooperation with the Austrian Avalanche and Torrent Control Service and the Bavarian Environmental Agency: 1) Based on the results of about 700 simulations of torrential rain on various soil vegetation complexes and land-use forms in the Eastern Alps a code of practice for assessment of surface runoff coefficients in torrential rain has been developed. By use of three indicator groups (soil conditions, sort and condition of plant cover, way and intensity of land-use / cultivation) runoff coefficients and surface roughness coefficients can be easily attributed to runoff contributing hydrological vegetation units. The big advantage: Dominant infiltration and runoff controlling processes are integrated in the assessed runoff and surface roughness coefficients. The manual is freely available under: http://bfw.ac.at/rz/bfwcms.web?dok=4342 (in German language). 2) The coefficients derived from field studies and/or GIS analysis form input parameters for the precipitation / runoff model ZEMOKOST (The runtime Method of ZEller MOdified by KOhl and STepanek), an MS-EXCEL based calculation tool which can be used with or without GIS-environment. The approach is permanently improved by addition of

  16. An integrative water balance model framework for a changing glaciated catchment in the Andes of Peru

    Science.gov (United States)

    Drenkhan, Fabian; Huggel, Christian; García Hernández, Javier; Fluixá-Sanmartín, Javier; Seidel, Jochen; Muñoz Asmat, Randy

    2017-04-01

    In the Santa River catchment [SRC] (Cordillera Blanca, Andes of Peru), human livelihoods strongly depend on year-round streamflow from glaciers and reservoirs, particularly in the dry season and in adjacent arid lowlands. Perennial glacial streamflow represents a buffer to water shortages, annual discharge variability and river contamination levels. However, climate change impacts, consecutive glacier shrinkage as well as new irrigated agriculture and hydropower schemes, population growth and thus water allocation might increase water scarcity in several areas of the SRC. This situation exerts further pressure and conflict potential over water resources and stresses the need to analyze both water supply and demand trends in a multidisciplinary and interlinked manner. In this context, an integrative glacio-hydrological framework was developed based on the Glacier and Snow Melt (GSM) and SOil CONTribution (SOCONT) models using the semi-distributed free software RS MINERVE. This water balance model incorporates hydroclimatic, socioeconomic and hydraulic objects and data at daily scale (with several gaps) for the last 50 years (1965-2015). A particular challenge in this context represents the poor data availability both in quantity and quality. Therefore, the hydroclimatic dataset to be used had to be carefully selected and data gaps were filled applying a statistical copula-based approach. The socioeconomic dataset of water demand was elaborated using several assumptions based on further census information and experiences from other projects in the region. Reservoirs and hydropower models were linked with additional hydraulic data. In order to increase model performance within a complex topography of the 11660 km2 SRC, the area was divided into 22 glaciated (GSM) and 42 non-glaciated (SOCONT) subcatchment models. Additionally, 382 elevation bands at 300 m interval were created and grouped into 22 different calibration zones for the whole SRC. The model was calibrated

  17. A disaggregating approach to describe overland flow occurrence within a catchment

    NARCIS (Netherlands)

    Vigiak, O.; Romanowicz, R.; van Loon, E.E.; Sterk, G.; Beven, K.J.

    2006-01-01

    A parametrically parsimonious, data-based model was built on observations at hillslope and catchment scale to simulate the distribution of overland flow within a small East African Highlands catchment (Kwalei, Tanzania). A rainfall-flow Data Based Mechanistic model identified catchment effective rai

  18. Effects of land use changes on ecohydrological results in a mesoscale Chinese catchment using an integrated modelling approach

    Science.gov (United States)

    Schmalz, Britta; Kuemmerlen, Mathias; Jähnig, Sonja; Fohrer, Nicola

    2013-04-01

    Land use and climate change affect water resources worldwide. Driven by rapid economic development and a high population pressure, land use changes occur in China particularly fast causing environmental impacts at various spatial and temporal scales. An integrated modelling approach for depicting the effect of environmental changes on aquatic ecosystems has been developed and tested. Thereby, the catchment properties and the presence of aquatic organisms were closely linked. The Changjiang catchment in the Poyang lake area in China was selected as a test area. Two measuring and sampling campaigns were jointly planned and carried out by hydrologists and hydrobiologists in October 2010 and February / March 2011. At 50 sampling points benthic macroinvertebrates were collected using the multi-habitat sampling method. The water and sediment balance of the entire catchment area was modelled with the ecohydrological model SWAT (Soil and Water Assessment Tool). The SWAT results as discharge and sediment time series at each of the 50 sampling points were transfered to the species distribution model BIOMOD. BIOMOD linked the occurrence of a taxon (benthic macroinvertebrates) with environmental variables at the sampling points and calculated extrapolated occurrence probabilities for the study area. The results show species distributions of benthic macroinvertebrates in dependence on various hydrological, climatic and topographic variables. Variables, which are connected to the hydrology, determine a high proportion of the modelled occurrence of the selected taxa. This approach can also be used with changing hydrological conditions to depict the impact of environmental change on aquatic ecosystems. Various land use scenarios were developed for the Chinese study area. On the one hand, intensification of agriculture was assumed; on the other hand, an afforestation of agricultural land was calculated. The distributions of benthic macroinvertebrates resulting from the hydrological

  19. Assimilation of remotely sensed latent heat flux in a distributed hydrological model

    NARCIS (Netherlands)

    Schuurmans, J.M.; Troch, P.A.A.; Veldhuizen, A.A.; Bastiaanssen, W.G.M.; Bierkens, M.F.P.

    2003-01-01

    This paper addresses the question of whether remotely sensed latent heat flux estimates over a catchment can be used to improve distributed hydrological model water balance computations by the process of data assimilation. The data used is a series of satellite images for the Drentse Aa catchment in

  20. Modeling of debris flow depositional patterns according to the catchments and sediment source areas characteristics

    Science.gov (United States)

    Tiranti, Davide; Deangeli, Chiara

    2015-03-01

    A method to predict the most probable flow rheology in Alpine debris flows is presented. The methods classifies outcropping rock masses in catchments on the basis of the type of resulting unconsolidated deposits. The grain size distribution of the debris material and the depositional style of past debris flow events are related to the dominant flow processes: viscoplastic and frictional/collisional. Three catchments in the upper Susa Valley (Western Alps), characterized by different lithologies, were selected for numerical analysis carried out with a Cellular Automata code with viscoplastic and frictional/collisional rheologies. The obtained numerical results are in good agreement with in site evidences in terms of depositional patterns, confirming the possibility of choosing the rheology of the debris flow based on the source material within the catchment.

  1. Use of modeling to protect, plan, and manage water resources in catchment areas.

    Science.gov (United States)

    Constant, Thibaut; Charrière, Séverine; Lioeddine, Abdejalil; Emsellem, Yves

    2016-08-01

    The degradation of water resources by diffuse pollution, mainly due to nitrate and pesticides, is an important matter for public health. Restoration of the quality of natural water catchments by focusing on their catchment areas is therefore a national priority in France. To consider catchment areas as homogeneous and to expend an equal effort on the entire area inevitably leads to a waste of time and money, and restorative actions may not be as efficient as intended. The variability of the pedological and geological properties of the area is actually an opportunity to invest effort on smaller areas, simply because every action is not equally efficient on every kind of pedological or geological surface. Using this approach, it is possible to invest in a few selected zones that will be efficient in terms of environmental results. The contributive hydraulic areas (CHA) concept is different from that of the catchment area. Because the transport of most of the mobile and persistent pollutants is primarily driven by water circulation, the concept of the CHA is based on the water pathway from the surface of the soil in the catchment area to the well. The method uses a three-dimensional hydrogeological model of surface and groundwater integrated with a geographic information system called Watermodel. The model calculates the contribution (m(3)/h or %) of each point of the soil to the total flow pumped in a well. Application of this model, partially funded by the Seine Normandy Basin Agency, to the catchment of the Dormelles Well in the Cretaceous chalk aquifer in the Orvanne valley, France (catchment area of 23,000 ha at Dormelles, county 77), shows that 95 % of the water pumped at the Dormelles Well comes from only 26 % of the total surface area of the catchment. Consequently, an action plan to protect the water resource will be targeted at the 93 farmers operating in this source area rather than the total number of farmers (250) across the entire 23,000 ha. Another

  2. Modelling soil erosion and associated sediment yield for small headwater catchments of the Daugava spillway valley, Latvia

    Science.gov (United States)

    Soms, Juris

    2015-04-01

    Albeluvisols, Albic Rubic Arenosols and Albic Stagnic Podzols with stony loamy - clayey diamicton to coarse sand textures prevail in the selected catchments. The results of modelling were validated through obtaining data on suspended sediment load directly during episodic runoff events caused by different scenarios of runoff formation. In order to get comparable values of suspended sediment load from gully catchments that differ in size, an area-specific daily suspended sediment yield was derived. The obtained results indicate that modelled area-specific sediment yield from the catchments to river greatly varies from 0.001 to 97.2 t ha-1 yr-1; the average soil loss predicted by RUSLE for the each of five catchments calculated for a 1 × 1 m cell grid totals 0.81; 1.36; 0.96; 1.05 and 1.55 t ha-1 yr-1 respectively. Notably, despite the presence of forest vegetation that cover more than 40% of area of three of these catchments, sizable plots of soils are potentially prone to erosion rates above the tolerable threshold, i.e. 0.3 t ha-1 yr-1. Comparison of modelled vs. measured values indicates that the applied RUSLE model underestimates real sediment delivery, which shortly can reach values 213.75 kg ha-1 day-1 during intense snow melting in spring. Nevertheless, results of GIS modelling can be reasonably used to estimate the spatial distribution of soil erosion risk and to identify potential erosion hotspots.

  3. Water balance modeling of Upper Blue Nile catchments using a top-down approach

    Directory of Open Access Journals (Sweden)

    S. Tekleab

    2010-09-01

    Full Text Available The hydrological behavior and functioning of twenty catchments in the Upper Blue Nile basin have been analyzed using a top-down modeling approach that is based on Budyko's hypotheses. The objective is to obtain better understanding of catchment response for prediction in ungauged catchments. The water balance analysis using Budyko-type curve at annual scale reveals that the aridity index does not exert a first order control in most of the catchments. This implies the need to increase model complexity to a monthly time scale to include the effects of seasonal soil moisture dynamics. The dynamic water balance model used in this study predicts the direct runoff and other processes based on limit concept. The uncertainty of model parameters has been assessed using the GLUE (Generalized Likelihood Uncertainty Estimation. The results show that the majority of the parameters are reasonably well identifiable. Moreover, a multi-objective model calibration strategy has been employed within the GLUE framework to emphasize the different aspects of the hydrographs on low and high flows. The model has been calibrated and validated against observed streamflow time series and it shows good performance for the twenty catchments of the upper Blue Nile. During the calibration period (1995–2000 the Nash and Sutcliffe coefficient of efficiency for monthly flow prediction varied between 0.52 to 0.93 during high flows, while it varied between 0.32 to 0.90 during low flows (logarithms of flow series. The model is parsimonious and it is suggested that the resulting parameters can be used to predict monthly stream flows in the ungauged catchments of the Upper Blue Nile basin, which accounts about 60% of total Nile basin flow.

  4. OpenLISEM Flash Flood Modelling Application in Logung Sub-Catchment, Central Java

    Directory of Open Access Journals (Sweden)

    Fitrie Atviana Nurritasari

    2016-02-01

    Full Text Available Juwana Catchment and Logung Sub-catchment in particular has been suffering several major past flood events with significant loss. This study conducted an assessment of flood risk by using OpenLISEM as physical soil and hydrological model to generate the single storm flash flood occurrences. The physical input data were collected from remote sensing image interpretation, field observation and measurement and literature review. There are three return periods chosen as scenarios that represent rainfall intensity in Logung Sub-Catchment. Model validation was done by adjusting initial moisture content and saturated hydraulic conductivity values to equate the calculated total discharge with the measured total discharge in several chosen dates. The results show increases in most of modeled hydrological parameter with respect to increasing of rainfall intensity.

  5. Network-based Modeling of Mesoscale Catchments - The Hydrology Perspective of Glowa-danube

    Science.gov (United States)

    Ludwig, R.; Escher-Vetter, H.; Hennicker, R.; Mauser, W.; Niemeyer, S.; Reichstein, M.; Tenhunen, J.

    Within the GLOWA initiative of the German Ministry for Research and Educa- tion (BMBF), the project GLOWA-Danube is funded to establish a transdisciplinary network-based decision support tool for water related issues in the Upper Danube wa- tershed. It aims to develop and validate integration techniques, integrated models and integrated monitoring procedures and to implement them in the network-based De- cision Support System DANUBIA. An accurate description of processes involved in energy, water and matter fluxes and turnovers requires an intense collaboration and exchange of water related expertise of different scientific disciplines. DANUBIA is conceived as a distributed expert network and is developed on the basis of re-useable, refineable, and documented sub-models. In order to synthesize a common understand- ing between the project partners, a standardized notation of parameters and functions and a platform-independent structure of computational methods and interfaces has been established using the Unified Modeling Language UML. DANUBIA is object- oriented, spatially distributed and raster-based at its core. It applies the concept of "proxels" (Process Pixel) as its basic object, which has different dimensions depend- ing on the viewing scale and connects to its environment through fluxes. The presented study excerpts the hydrological view point of GLOWA-Danube, its approach of model coupling and network based communication (using the Remote Method Invocation RMI), the object-oriented technology to simulate physical processes and interactions at the land surface and the methodology to treat the issue of spatial and temporal scal- ing in large, heterogeneous catchments. The mechanisms applied to communicate data and model parameters across the typical discipline borders will be demonstrated from the perspective of a land-surface object, which comprises the capabilities of interde- pendent expert models for snowmelt, soil water movement, runoff formation, plant

  6. Modelling the catchment-scale environmental impacts of wastewater treatment in an urban sewage system for CO₂ emission assessment.

    Science.gov (United States)

    Mouri, Goro; Oki, Taikan

    2010-01-01

    Water shortages and water pollution are a global problem. Increases in population can have further acute effects on water cycles and on the availability of water resources. Thus, wastewater management plays an important role in mitigating negative impacts on natural ecosystems and human environments and is an important area of research. In this study, we modelled catchment-scale hydrology, including water balances, rainfall, contamination, and urban wastewater treatment. The entire water resource system of a basin, including a forest catchment and an urban city area, was evaluated synthetically from a spatial distribution perspective with respect to water quantity and quality; the Life Cycle Assessment (LCA) technique was applied to optimize wastewater treatment management with the aim of improving water quality and reducing CO₂ emissions. A numerical model was developed to predict the water cycle and contamination in the catchment and city; the effect of a wastewater treatment system on the urban region was evaluated; pollution loads were evaluated quantitatively; and the effects of excluding rainwater from the treatment system during flooding and of urban rainwater control on water quality were examined. Analysis indicated that controlling the amount of rainwater inflow to a wastewater treatment plant (WWTP) in an urban area with a combined sewer system has a large impact on reducing CO₂ emissions because of the load reduction on the urban sewage system.

  7. Calibration of a transient transport model to tritium measurements in rivers and streams in the Western Lake Taupo catchment, New Zealand

    Directory of Open Access Journals (Sweden)

    M. A. Gusyev

    2012-08-01

    Full Text Available Here we present a general approach of calibrating transient transport models to tritium concentrations in river waters developed for the MT3DMS/MODFLOW model of the Western Lake Taupo catchment, New Zealand. Tritium is a time-dependent tracer with radioactive half-life of 12.32 yr. In the transport model, the tritium input (measured in rain passes through the groundwater system, and the modelled tritium concentrations are compared to the measured tritium concentrations in the river outlets for the Waihaha, Whanganui, Whareroa, Kuratau and Omori river catchments from 2000–2007. For the Kuratau River, tritium was also measured between 1960 and 1970, which allowed us to fine-tune the transport model. In order to incorporate all surface flows from rivers to small streams, an 80 m uniform grid cell size was selected in the steady-state MODFLOW model for the model area of 1072 km2. The groundwater flow model was first calibrated to groundwater levels and stream flow observations. Then, the transport model was calibrated to the measured tritium concentrations in the river waters. The MT3DMS model results show good agreement with the measured tritium values in all five river catchments. Finally, the calibrated MT3DMS model is applied to simulate groundwater ages that are used to construct groundwater age distributions for the river catchments.

  8. Influence of landscape position and transient water table on soil development and carbon distribution in a steep, headwater catchment

    Science.gov (United States)

    Scott W. Bailey; Patricia A. Brousseau; Kevin J. McGuire; Donald S. Ross

    2014-01-01

    Upland headwater catchments, such as those in the AppalachianMountain region, are typified by coarse textured soils, flashy hydrologic response, and low baseflow of streams, suggesting well drained soils and minimal groundwater storage. Model formulations of soil genesis, nutrient cycling, critical loads and rainfall/runoff response are typically based on vertical...

  9. Hydrological hysteresis and its value for assessing process consistency in catchment conceptual models

    Science.gov (United States)

    O. Fovet; L. Ruiz; M. Hrachowitz; M. Faucheux; C. Gascuel-Odoux

    2015-01-01

    While most hydrological models reproduce the general flow dynamics, they frequently fail to adequately mimic system-internal processes. In particular, the relationship between storage and discharge, which often follows annual hysteretic patterns in shallow hard-rock aquifers, is rarely considered in modelling studies. One main reason is that catchment storage is...

  10. Development of a hydrological model for simulation of runoff from catchments unbounded by ridge lines

    Science.gov (United States)

    Vema, Vamsikrishna; Sudheer, K. P.; Chaubey, I.

    2017-08-01

    Watershed hydrological models are effective tools for simulating the hydrological processes in the watershed. Although there are a plethora of hydrological models, none of them can be directly applied to make water conservation decisions in irregularly bounded areas that do not confirm to topographically defined ridge lines. This study proposes a novel hydrological model that can be directly applied to any catchment, with or without ridge line boundaries. The model is based on the water balance concept, and a linear function concept to approximate the cross-boundary flow from upstream areas to the administrative catchment under consideration. The developed model is tested in 2 watersheds - Riesel Experimental Watershed and a sub-basin of Cedar Creek Watershed in Texas, USA. Hypothetical administrative catchments that did not confirm to the location of ridge lines were considered for verifying the efficacy of the model for hydrologic simulations. The linear function concept used to account the cross boundary flow was based on the hypothesis that the flow coming from outside the boundary to administrative area was proportional to the flow generated in the boundary grid cell. The model performance was satisfactory with an NSE and r2 of ≥0.80 and a PBIAS of <25 in all the cases. The simulated hydrographs for the administrative catchments of the watersheds were in good agreement with the observed hydrographs, indicating a satisfactory performance of the model in the administratively bounded areas.

  11. Modelling catchment-scale erosion patterns in the East African Highlands

    NARCIS (Netherlands)

    Vigiak, O.; Okoba, B.O.; Sterk, G.; Groenenberg, S.

    2005-01-01

    Prompt location of areas exposed to high erosion is of the utmost importance for soil and water conservation planning. Erosion models can be useful tools to locate sources of sediment and areas of deposition within a catchment, but the reliability of model predictions of spatial patterns of erosion

  12. Water quality improvements from afforestation in an agricultural catchment in Denmark illustrated with the INCA model

    DEFF Research Database (Denmark)

    Bastrup-Birk, A.; Gundersen, P.

    2004-01-01

    Intensive agricultural land use across Europe has altered nitrogen (N) budget of catchments substantially, causing widespread N pollution of freshwater. Although the N cycle in forests has changed due to increased N deposition, most forest soil waters in Europe have low nitrate concentrations....... The protective function of forests on water quality has led to increasing interest in the planting of new forests on arable land as a measure to protect valuable or sensitive freshwater resources. The paper illustrates the effects of afforestation on water and N cycling using the Integrated Nitrogen Catchment...... (INCA) model. The model was calibrated on the Horndrup catchment in the eastern part of Jutland, Denmark, which is dominated by agricultural land use but also covered by 18% of forest land. The dynamics of nitrate concentrations in the stream water were simulated successfully by INCA over a three...

  13. Estimating aquifer properties and distributed groundwater recharge in a hard-rock catchment of Udaipur, India

    Science.gov (United States)

    Machiwal, Deepesh; Singh, P. K.; Yadav, K. K.

    2016-09-01

    The present study determined aquifer parameters in hard-rock aquifer system of Ahar River catchment, Udaipur, India by conducting 19 pumping tests in large-diameter wells. Spreadsheet programs were developed for analyzing pumping test data, and their accuracy was evaluated by root mean square error (RMSE) and correlation coefficient (R). Histograms and Shapiro-Wilk test indicated non-normality (p value 0.95). Distribution of the aquifer parameters and recharge indicated that the northern portion with high ground elevations (575-700 m MSL), and high S y (0.08-0.25) and T (>600 m2/day) values may act as recharge zone. The T and S y values revealed significant spatial variability, which suggests strong heterogeneity of the hard-rock aquifer system. Overall, the findings of this study are useful to formulate appropriate strategies for managing water resources in the area. Also, the developed spreadsheet programs may be used to analyze the pumping test data of large-diameter wells in other hard-rock regions of the world.

  14. Geostatistical analysis of soil moisture distribution in a part of Solani River catchment

    Science.gov (United States)

    Kumar, Kamal; Arora, M. K.; Hariprasad, K. S.

    2016-03-01

    The aim of this paper is to estimate soil moisture at spatial level by applying geostatistical techniques on the point observations of soil moisture in parts of Solani River catchment in Haridwar district of India. Undisturbed soil samples were collected at 69 locations with soil core sampler at a depth of 0-10 cm from the soil surface. Out of these, discrete soil moisture observations at 49 locations were used to generate a spatial soil moisture distribution map of the region. Two geostatistical techniques, namely, moving average and kriging, were adopted. Root mean square error (RMSE) between observed and estimated soil moisture at remaining 20 locations was determined to assess the accuracy of the estimated soil moisture. Both techniques resulted in low RMSE at small limiting distance, which increased with the increase in the limiting distance. The root mean square error varied from 7.42 to 9.77 in moving average method, while in case of kriging it varied from 7.33 to 9.99 indicating similar performance of the two techniques.

  15. Soil and water assessment tool model calibration results for different catchment sizes in poland.

    Science.gov (United States)

    Ostojski, Mieczyslaw S; Niedbala, Jerzy; Orlinska-Wozniak, Paulina; Wilk, Pawel; Gębala, Joanna

    2014-01-01

    The watershed model SWAT (Soil and Water Assessment Tool) can be used to implement the requirements of international agreements that Poland has ratified. Among these requirements are the establishment of catchment-based, rather than administrative-based, management plans and spatial information systems. Furthermore, Polish law requires that management of water resources be based on catchment systems. This article explores the use of the SWAT model in the implementation of catchment-based water management in Poland. Specifically, the impacts of basin size on calibration and on the results of the simulation process were analyzed. SWAT was set up and calibrated for three Polish watersheds of varying sizes: (i) Gąsawka, a small basin (>593.7 km), (ii) Rega, a medium-sized basin (2766.8 km), and (iii) Warta, a large basin (54,500 km) representing about 17.4% of Polish territory. The results indicated that the size of the catchment has an impact on the calibration process and simulation outputs. Several factors influenced by the size of the catchment affected the modeling results. Among these factors are the number of measurement points within the basin and the length of the measuring period and data quality at checkpoints as determined by the position of the measuring station. It was concluded that the SWAT model is a suitable tool for the implementation of catchment-based water management in Poland regardless of watershed size. Copyright © by the American Society of Agronomy, Crop Science Society of America, and Soil Science Society of America, Inc.

  16. Upscaling a catchment-scale ecohydrology model for regional-scale earth system modeling

    Science.gov (United States)

    Adam, J. C.; Tague, C.; Liu, M.; Garcia, E.; Choate, J.; Mullis, T.; Hull, R.; Vaughan, J. K.; Kalyanaraman, A.; Nguyen, T.

    2014-12-01

    With a focus on the U.S. Pacific Northwest (PNW), BioEarth is an Earth System Model (EaSM) currently in development that explores the interactions between coupled C:N:H2O dynamics and resource management actions at the regional scale. Capturing coupled biogeochemical processes within EaSMs like BioEarth is important for exploring the response of the land surface to changes in climate and resource management actions; information that is important for shaping decisions that promote sustainable use of our natural resources. However, many EaSM frameworks do not adequately represent landscape-scale ( 10 km) are necessitated by computational limitations. Spatial heterogeneity in a landscape arises due to spatial differences in underlying soil and vegetation properties that control moisture, energy and nutrient fluxes; as well as differences that arise due to spatially-organized connections that may drive an ecohydrologic response by the land surface. While many land surface models used in EaSM frameworks capture the first type of heterogeneity, few account for the influence of lateral connectivity on land surface processes. This type of connectivity can be important when considering soil moisture and nutrient redistribution. The RHESSys model is utilized by BioEarth to enable a "bottom-up" approach that preserves fine spatial-scale sensitivities and lateral connectivity that may be important for coupled C:N:H2O dynamics over larger scales. RHESSys is a distributed eco-hydrologic model that was originally developed to run at relatively fine but computationally intensive spatial resolutions over small catchments. The objective of this presentation is to describe two developments to enable implementation of RHESSys over the PNW. 1) RHESSys is being adapted for BioEarth to allow for moderately coarser resolutions and the flexibility to capture both types of heterogeneity at biome-specific spatial scales. 2) A Kepler workflow is utilized to enable RHESSys implementation over

  17. Integrating observations and models to help understanding how flooding impacts upon catchments as a basis for decision making.

    Science.gov (United States)

    Owen, Gareth; Quinn, Paul; O'Donnell, Greg

    2014-05-01

    This paper explains how flood management projects might be better informed in the future by using more observations and a novel impact modelling tool in a simple transparent framework. The understanding of how local scale impacts propagate downstream to impact on the downstream hydrograph is difficult to determine using traditional rainfall runoff and hydraulic routing methods. The traditional approach to modelling essentially comprises selecting a fixed model structure and then calibrating to an observational hydrograph, which make those model predictions highly uncertain. Here, a novel approach is used in which the structure of the runoff generation is not specified a priori and incorporates expert knowledge. Rather than using externally for calibration, the observed outlet hydrographs are used directly within the model. Essentially the approach involves the disaggregation of the outlet hydrograph by making assumptions about the spatial distribution of runoff generated. The channel network is parameterised through a comparison of the timing of observed hydrographs at a number of nested locations within the catchment. The user is then encouraged to use their expert knowledge to define how runoff is generated locally and what the likely impact of any local mitigation is. Therefore the user can specify any hydrological model or flow estimation method that captures their expertise. Equally, the user is encouraged to install as many instruments as they can afford to cover the catchment network. A Decision Support Matrix (DSM) is used to encapsulate knowledge of the runoff dynamics gained from simulation in a simple visual way and hence to convey the likely impacts that arise from a given flood management scenario. This tool has been designed primarily to inform and educate landowners, catchment managers and decision makers. The DSM outlines scenarios that are likely to increase or decrease runoff rates and allows the user to contemplate the implications and

  18. Using interactive recession curve analysis to specify a general catchment storage model

    Directory of Open Access Journals (Sweden)

    R. Lamb

    1997-01-01

    Full Text Available An analysis of hydrograph recessions can be used to identify the parameters of a conceptual catchment storage irnodel and, with the advent of large-scale digital data storage and automated logging systems, it has become desirable to automate recession curve analysis. Various studies have thus reported algorithms used to infer 'baseflow' storage models automatically from recession data. Such algorithms commonly operate by maximising the fit of measured recession data to some a priori function. Here, an alternative approach is taken in which the appropriate form for a catchment saturated zone store is investigated by combining observed recession data to form a Master Recession Curve (MRC. This is done within a software package that offers automated functions to help select recession periods suitable for inclusion within the MRC. These recession periods are combined automatically to form a 'prototype' MRC, which can be modified interactively to overcome problems such as unrepresentative or sparse data. The master recession for a catchment is used to calculate an empirical catchment-averaged discharge-relative storage (QΔS relationship. The method is considered to be general because the QΔS relationship may be of arbitrary form. Examples are given, showing the derivation for three catchments of different QΔS functions.

  19. Hydrological response to climate change in the Lesse and the Vesdre catchments: contribution of a physically based model (Wallonia, Belgium

    Directory of Open Access Journals (Sweden)

    A. Bauwens

    2011-06-01

    Full Text Available The Meuse is an important rain-fed river in North-Western Europe. Nine million people live in its catchment, split over five countries. Projected changes in precipitation and temperature characteristics due to climate change would have a significant impact on the Meuse River and its tributaries. In this study, we focused on the impacts of climate change on the hydrology of two sub-catchments of the Meuse in Belgium, the Lesse and the Vesdre, placing the emphasis on the water-soil-plant continuum in order to highlight the effects of climate change on plant growth, and water uptake on the hydrology of two sub-catchments. These effects were studied using two climate scenarios and a physically based distributed model, which reflects the water-soil-plant continuum. Our results show that the vegetation will evapotranspirate between 10 and 17 % less at the end of the century because of water scarcity in summer, even if the root development is better under climate change conditions. In the low scenario, the mean minimal 7 days discharge value could decrease between 19 and 24 % for a two year return period, and between 20 and 35 % for a fifty year return period. It will lead to rare but severe drought in rivers, with potentially huge consequences on water quality.

  20. Combining data sources to characterise climatic variability for hydrological modelling in high mountain catchments

    Science.gov (United States)

    Pritchard, David; Fowler, Hayley; Bardossy, Andras; O'Donnell, Greg; Forsythe, Nathan

    2016-04-01

    Robust hydrological modelling of high mountain catchments to support water resources management depends critically on the accuracy of climatic input data. However, the hydroclimatological complexity and sparse measurement networks typically characteristic of these environments present significant challenges for determining the structure of spatial and temporal variability in key climatic variables. Focusing on the Upper Indus Basin (UIB), this research explores how different data sources can be combined in order to characterise climatic patterns and related uncertainties at the scales required in hydrological modelling. Analysis of local observations with respect to underlying climatic processes and variability is extended relative to previous studies in this region, which forms a basis for evaluating the domains of applicability and potential insights associated with selected remote sensing and reanalysis products. As part of this, the information content of recent high resolution simulations for understanding climatic patterns is assessed, with particular reference to the High Asia Refined Analysis (HAR). A strategy for integrating these different data sources to obtain plausible realisations of the distributed climatic fields needed for hydrological modelling is developed on the basis of this analysis, which provides a platform for exploring uncertainties arising from potential biases and other sources of error. The interaction between uncertainties in climatic input data and alternative approaches to process parameterisation in hydrological and cryospheric modelling is explored.

  1. Rainfall-runoff modelling using different estimators of precipitation data in the Carpathian mountain catchments (South Poland)

    Science.gov (United States)

    Kasina, Michal; Ziemski, Michal; Niedbala, Jerzy; Malota, Agnieszka

    2013-04-01

    Precipitation observations are an essential element of flood forecasting systems. Rain gauges, radars, satellite sensors and forecasts from high resolution numerical weather prediction models are a part of precipitation monitoring networks. These networks collect rainfall data that are further provided to hydrological models to produce forecasts. The main goal of this work is to assess the usage of different precipitation data sources in rainfall-runoff modelling with reference to Flash Flood Early Warning System. STUDY AREA Research was carried out in the upper parts of the Sola and Raba river catchments. Both of the rivers begin their course in the southern part of the Western Beskids (Outer Eastern Carpathians; southern Poland). For the purpose of this study, both rivers are taken to comprise the catchments upstream of the gauging stations at Zywiec (Sola) and Stroza (Raba). The upper Sola river catchment encompasses an area of 785 sq. km with an altitude ranging from 342 to 1236 m above sea level, while the Raba river catchment occupies an area of 644 sq. km with an altitude ranging from 300 to 1266 m above sea level. The catchments are underlain mainly by flysch sediments. The average annual amount of precipitation for the Sola River catchment is between 750 and 1300 mm and for the Raba river catchment is in the range of 800-1000 mm. METHODS AND RESULTS This work assesses the sensitivity of a lumped hydrological model DHI's Nedbør-Afrstrømnings-Model (NAM) to different sources of rainfall estimates: rain gauges, radar and satellite as well as predicted precipitation amount from high resolution numerical weather prediction models (e.g. ALADIN). The main steps of validation procedure are: i) comparison of rain gauge data with other precipitation data sources, ii) calibration of the hydrological model (using historical, long time series of rain gauge data treated as "ground truth"), iii) validation using different precipitation data sources as an input, iii

  2. Deterministic slope failure hazard assessment in a model catchment and its replication in neighbourhood terrain

    Directory of Open Access Journals (Sweden)

    Kiran Prasad Acharya

    2016-01-01

    Full Text Available In this work, we prepare and replicate a deterministic slope failure hazard model in small-scale catchments of tertiary sedimentary terrain of Niihama city in western Japan. It is generally difficult to replicate a deterministic model from one catchment to another due to lack of exactly similar geo-mechanical and hydrological parameters. To overcome this problem, discriminant function modelling was done with the deterministic slope failure hazard model and the DEM-based causal factors of slope failure, which yielded an empirical parametric relationship or a discriminant function equation. This parametric relationship was used to predict the slope failure hazard index in a total of 40 target catchments in the study area. From ROC plots, the prediction rate between 0.719–0.814 and 0.704–0.805 was obtained with inventories of September and October slope failures, respectively. This means September slope failures were better predicted than October slope failures by approximately 1%. The results show that the prediction of the slope failure hazard index is possible, even in a small catchment scale, in similar geophysical settings. Moreover, the replication of the deterministic model through discriminant function modelling was found to be successful in predicting typhoon rainfall-induced slope failures with moderate to good accuracy without any use of geo-mechanical and hydrological parameters.

  3. A multi-criteria parameterisation strategy for the hydrological modelling of storm events in an agricultural catchment

    Science.gov (United States)

    Hallema, D. W.; Moussa, R.

    2009-04-01

    The parameterisation of physically based hydrological models is a key factor in evaluating their performance and improving their adequacy. In comparison to natural catchments, the parameterisation of agricultural catchment models requires a special approach since agricultural practice, such as tillage, introduces a temporal variability in the hydraulic conductivity of the soil. This study aims to develop and evaluate a parameterisation strategy for the hydrological modelling of storm events in a Mediterranean agricultural catchment. The adopted methodology accounts for a spatio-temporally variable land use, combined with the presence of an artificial drainage network and the occurrence of short duration-high intensity storm events. A parameterisation of 43 events covering a 12-year period was carried out applying MHYDAS (Distributed HYdrological Modelling for AgroSystems) to the Roujan catchment (0.91 km2) in southern France. Parameterisation of MHYDAS is particularly difficult considering the large number of spatio-temporally variable parameters involved. To incorporate this variability, the catchment was divided into hydrological units that are considered hydrologically homogeneous, mostly parcels separated by field boundaries and ditches. The parameterisation was performed in four parts. Firstly, the appropriate flood routing equation was selected for each channel reach in the drainage network: kinematic wave where possible and diffuse wave for the other reaches. Secondly, the boundary conditions (geometry, connectivity and roughness of hydrological units and ditches) were assumed equal for all events, while soil hydrodynamic properties and initial soil moisture content were taken variable in time. A third step was to calibrate individual events by manually tuning the average overland- and channel flow celerity, saturated hydraulic conductivity, and two coefficients for the channel infiltration and exfiltration fluxes. The predictive power of each simulation was

  4. Modelling the impact of implementing Water Sensitive Urban Design on at a catchment scale

    DEFF Research Database (Denmark)

    Locatelli, Luca; Gabriel, S.; Bockhorn, Britta

    Stormwater management using Water Sensitive Urban Design (WSUD) is expected to be part of future drainage systems. This project aimed to develop a set of hydraulic models of the Harrestrup Å catchment (close to Copenhagen) in order to demonstrate the importance of modeling WSUDs at different scales......, ranging from models of an individual soakaway up to models of a large urban catchment. The models were developed in Mike Urban with a new integrated soakaway model. A small-scale individual soakaway model was used to determine appropriate initial conditions for soakway models. This model was applied...... to a 22 year rain time series and statistical analysis performed. Results show that soakaways, depending on the design criteria, are on average 20-60% full at the beginning of rain events; outflow intensities from soakaways are reduced depending on the soakaway design return period, and the annual...

  5. A mediated modelling approach to promote collaborative learning in Andean rural micro-catchments in Colombia

    Science.gov (United States)

    Gowing, John; Dominguez, Isabel

    2013-04-01

    In rural catchments of developing countries water-related diseases, due to land use patterns (agriculture and livestock), microbial pollution, inadequate sanitation systems, access to water of poor quality, and lack of institutional support are common problems which disproportionally affect poor and vulnerable people. This research aims at developing a system dynamic model to improve the understanding of the macro and micro factors that influence human health and environmental health in rural micro-catchments in Valle del Cauca, Colombia. In this catchment livelihoods for most people depend on agriculture, particularly coffee. The research uses a mediated modeling approach, in which different stakeholders in modeling sessions, develop a STELLA model that allows them to identify relations between the economic, social and environmental factors and driving forces over the performance of their system. Stakeholders jointly develop the model structure in sessions facilitated by the researcher and the data required is gathered using secondary information from the different relevant institutions and primary information from field surveys that cover socioeconomic and environmental aspects that has not been previously collected by any institution or organization (i.e. household survey, stream water survey, and drinking water survey). Representation and understanding of their system will allow the stakeholders to test the effect of different management strategies in the micro-catchment and their associated socioeconomic, environmental and human health outcomes.

  6. Modelling the effect of field management on crop water productivity and catchment hydrology

    Science.gov (United States)

    Van Gaelen, Hanne; Willems, Patrick; Diels, Jan; Raes, Dirk

    2014-05-01

    Upgrading crop water productivity (WPET) is crucial to assure food production in a future world, where simultaneously the world population grows and land and water resources become increasingly limited. Adapted field management is one of the key solutions to upgrade WPET for rainfed agriculture in drought prone regions. However field management strategies should be assessed considering their impact on a larger scale (catchment hydrology), and this for current and future climatic conditions. By linking a crop water productivity model (AquaCrop) to a lumped conceptual hydrological model (VHM), we aimed to develop a general modeling procedure to evaluate the impact of field management on WPET and catchment hydrology. To avoid disadvantages related to other model approaches, we specifically aimed at a procedure that (i) can be applied for both current and future climatic conditions, (ii) is widely applicable and generally relevant, i.e. also for developing countries, and (iii) requires a relatively small number of explicit parameters and mostly-intuitive input variables. The linkage between AquaCrop and VHM is tested for two catchments in Flanders with a high proportion of agricultural land. After the VHM model is calibrated and AquaCrop simulations are run for the different land units (crop-soil combinations) of the catchment, the response behaviour of the VHM unsaturated zone model and the AquaCrop soil water balance is compared. Differences are identified and interpreted and a final coupling of the two models is established trough the water balance of the unsaturated zone. Thereby the overland runoff and water percolation to the groundwater or subsurface flow are the most crucial linkage components. After both models are linked different field management scenarios can be investigated with respect to their effect on both WPET and catchment hydrology.

  7. Small-scale Rainfall Challenges Tested with Semi-distributed and Distributed Hydrological Models

    Science.gov (United States)

    Ichiba, Abdellah; Tchiguirinskaia, Ioulia; Gires, Auguste; Schertzer, Daniel; Bompard, Philippe

    2016-04-01

    Nowadays, there is a growing interest on small-scale rainfall information, provided by weather radars, to be used in urban water management and decision-making. Indeed, it helps to better understand the essential interactions between natural and man-made urban environments, both being complex systems. However the integration of this information in hydrological models remains a big challenge. In fact, urban water managers often rely on lumped or semi-distributed models with much coarser data resolution. The scope of this work is to investigate the sensitivity of two hydrological models to small-scale rainfall, and their potential improvements to integrate wholly the small-scale information. The case study selected to perform this study is a small urban catchment (245 ha), located at Val-de-Marne county (southeast of Paris, France). Investigations were conducted using either CANOE model, a semi-distributed conceptual model that is widely used in France for urban modeling, or a fully distributed and physically based model, Multi-Hydro, developed at Ecole des Ponts ParisTech (www hmco-dev.enpc.fr/Tools-Training/Tools/Multi-Hydro.php). Initially, in CANOE model the catchment was divided into 9 sub-catchments with size ranging from 1ha to 76ha. A refinement process was conduced in the framework of this investigation in order to improve the model resolution by considering higher number of smaller sub-catchments. The new configuration consists of 44 sub-catchments with size ranging from 1ha-14ha. The Multi-Hydro modeling approach consists on rasterizing the catchment information to a regular spatial grid of a resolution chosen by the user. Each pixel is then affected by specific information, e.g., a unique land type per pixel, for which hydrological and physical properties are set. First of all, both models were validated with respect to real flow measurements using three types of rainfall data: (1) point measurement data coming form the Sucy-en-Brie rain gauge; (2) Meteo

  8. Model representation of the Sudanian hydrological processes: Application on the Donga catchment (Benin)

    Science.gov (United States)

    Le Lay, M.; Saulnier, G.-M.; Galle, S.; Seguis, L.; Métadier, M.; Peugeot, Ch.

    2008-12-01

    SummaryDuring the AMMA (African Monsoon Multidisciplinary Analysis) program, intensive field experiments were conducted on the Donga catchment (586 km 2), which is part of the Ouémé surveyed hydrological watershed (14,400 km 2). Based on these studies, a number of general hydrological assumptions were derived to explain the hydrological functioning of catchments located in the Sudanian hydrological area of West Africa. To take advantage of this field-acquired knowledge in the study of the impacts of climate and anthropogenic changes in these catchments, a model (TOPAMMA) was derived based on these hydrological assumptions. Subsurface lateral fluxes were described in the model using the TOPMODEL framework. The recharge of the deep water table was also modelled, taking into account its disconnection from the river network. Simple geomorphologic approaches were used to estimate the time-transfer of both surface and subsurface water fluxes. Finally, to be consistent with the available meteorological data, a simple parameterization of evapotranspiration was added to the model. This paper details this modelisation as well as its corroboration on the Donga catchment. The data collected over the catchment during the 2002-2004 periods was therefore used at different scales, within either a quantitative or qualitative perspective. The results show that the model representation of the water cycle is quite realistic, which allows the AMMA community to have a useful tool available for water balance studies on the Sudanian region. However, further field investigations are necessary to confirm main model assumptions. Finally, the process representation in the model is now improved, especially with regard to the description of spatial land-surface heterogeneities and surface-atmosphere interactions.

  9. Requirements on catchment modelling for an optimized reservoir operation in water deficient regions

    Science.gov (United States)

    Froebrich, J.; Kirkby, M. J.; Reder, C.

    2002-12-01

    To provide long term water security in water deficient regions, the interaction of erosion, pollutant emission, the impact of irrigation areas, the characteristics of ephemeral streams and resulting water quality in reservoirs must be considered in water management plans. In many semiarid regions, reservoirs are the only source of water, the indispensable element required for human existence. By the year 2000 the world had built many small and > 45,000 large dams. In these reservoirs, water quality and quantity are affected both by climate change and catchment land use. Results of past projects indicate that the specific control of reservoirs can lead to a significant improvement of water quality, but reservoirs have already transformed the quantity and quality of surface waters in a remarkable manner. Reservoirs with their distinct behaviour as reactors could therefore be considered as key elements in semiarid and arid catchments, linking and transforming rivers and channels. Effective practical operation schemes require a thorough knowledge of spatial and temporal variation in water quality and quantity, and simulation models can be used to support the identification of most effective management potentials at catchment scale. We discuss here the particular requirements for water quality modelling at catchment scale in semiarid and arid regions. Results of reservoir water quality modelling are presented. The potential of catchment models like the PESERA model is demonstrated. Knowledge gaps, such as the consideration of ephemeral streams in catchment models, are addressed and fresh problem solving strategies are introduced. Erosion models like PESERA can provide important information on sediment transport and hence describing the carrier potentials for organic matter, heavy metals and pesticides from terrestrial areas into the water courses. The new EU-research project tempQsim will improve understanding of how the organic matter is transformed in river beds

  10. Tropical Peatland water management modelling of the Air Hitam Laut catchment in Indonesia

    NARCIS (Netherlands)

    Wösten, H.; Hooijer, A.; Siderius, C.; Dira Satriadi Rais,; Aswandi Idris,; Rieley, J.

    2006-01-01

    Human induced land use change and associated fire alter profoundly the hydrology of tropical peatlands and thus affect the functioning of entire river catchments. The hydrological model SIMGRO was used to calculate the effects of drainage on peat water levels, peat surface morphology and river flows

  11. A detailed model for simulation of catchment scale subsurface hydrologic processes

    Science.gov (United States)

    Paniconi, Claudio; Wood, Eric F.

    1993-01-01

    A catchment scale numerical model is developed based on the three-dimensional transient Richards equation describing fluid flow in variably saturated porous media. The model is designed to take advantage of digital elevation data bases and of information extracted from these data bases by topographic analysis. The practical application of the model is demonstrated in simulations of a small subcatchment of the Konza Prairie reserve near Manhattan, Kansas. In a preliminary investigation of computational issues related to model resolution, we obtain satisfactory numerical results using large aspect ratios, suggesting that horizontal grid dimensions may not be unreasonably constrained by the typically much smaller vertical length scale of a catchment and by vertical discretization requirements. Additional tests are needed to examine the effects of numerical constraints and parameter heterogeneity in determining acceptable grid aspect ratios. In other simulations we attempt to match the observed streamflow response of the catchment, and we point out the small contribution of the streamflow component to the overall water balance of the catchment.

  12. Landscape-based hydrological modelling: Understanding the influence of climate, topography, and vegetation on catchment hydrology

    NARCIS (Netherlands)

    Gao, H.

    2015-01-01

    In this thesis, a novel landscape-based hydrological model is presented that was developed and tested in numerous catchments around the world with various landscapes and climate conditions. A landscape is considered to consist of a topography and an ecosystem living on it. Firstly, the influence of

  13. Hydrology under change: an evaluation protocol to investigate how hydrological models deal with changing catchments

    Science.gov (United States)

    G. Thirel; V. Andreassian; C. Perrin; J.-N. Audouy; L. Berthet; Pamela Edwards; N. Folton; C. Furusho; A. Kuentz; J. Lerat; G. Lindstrom; E. Martin; T. Mathevet; R. Merz; J. Parajka; D. Ruelland; J. Vaze

    2015-01-01

    Testing hydrological models under changing conditions is essential to evaluate their ability to cope with changing catchments and their suitability for impact studies. With this perspective in mind, a workshop dedicated to this issue was held at the 2013 General Assembly of the International Association of Hydrological Sciences (IAHS) in Göteborg, Sweden, in July 2013...

  14. Impacts of Noah model physics on catchment-scale runoff simulations

    NARCIS (Netherlands)

    Zheng, D.; Velde, van der R.; Su, Z.; Wen, J.; Wang, X.; Booij, M.J.; Hoekstra, A.Y.; Lv, S.; Ek, M.B.

    2016-01-01

    Noah model physics options validated for the source region of the Yellow River (SRYR) are applied to investigate their ability in reproducing runoff at the catchment scale. Three sets of augmentations are implemented affecting descriptions of (i) turbulent and soil heat transport (Noah-H), (ii) soil

  15. Review article: Hydrological modeling in glacierized catchments of central Asia - status and challenges

    Science.gov (United States)

    Chen, Yaning; Li, Weihong; Fang, Gonghuan; Li, Zhi

    2017-02-01

    Meltwater from glacierized catchments is one of the most important water supplies in central Asia. Therefore, the effects of climate change on glaciers and snow cover will have increasingly significant consequences for runoff. Hydrological modeling has become an indispensable research approach to water resources management in large glacierized river basins, but there is a lack of focus in the modeling of glacial discharge. This paper reviews the status of hydrological modeling in glacierized catchments of central Asia, discussing the limitations of the available models and extrapolating these to future challenges and directions. After reviewing recent efforts, we conclude that the main sources of uncertainty in assessing the regional hydrological impacts of climate change are the unreliable and incomplete data sets and the lack of understanding of the hydrological regimes of glacierized catchments of central Asia. Runoff trends indicate a complex response to changes in climate. For future variation of water resources, it is essential to quantify the responses of hydrologic processes to both climate change and shrinking glaciers in glacierized catchments, and scientific focus should be on reducing uncertainties linked to these processes.

  16. Carbon budget estimation of a subarctic catchment using a dynamic ecosystem model at high spatial resolution

    Directory of Open Access Journals (Sweden)

    J. Tang

    2015-01-01

    Eriophorum, Sphagnum and then tundra heath during the observation periods. The catchment-level carbon fluxes from aquatic systems are dominated by CO2 emissions from streams. Integrated across the whole catchment, we estimate that the area is a carbon sink at present, and will become an even stronger carbon sink by 2080, which is mainly a result of a projected densification of birch forest and its encroachment into tundra heath. However, the magnitudes of the modelled sinks are very dependent on future atmospheric CO2 concentrations. Furthermore, comparisons of global warming potentials between two simulations with and without CO2 increase since 1960 reveal that the increased methane emission from the peatland could double the warming effects of the whole catchment by 2080 in the absence of CO2 fertilization of the vegetation. This is the first process-based model study of the temporal evolution of a catchment-level carbon budget at high spatial resolution, integrating comprehensive and diverse fluxes including both terrestrial and aquatic carbon. Though this study also highlights some limitations in modelling subarctic ecosystem responses to climate change including aquatic system flux dynamics, nutrient limitation, herbivory and other disturbances and peatland expansion, our application provides a mechanism to resolve the complexity of carbon cycling in subarctic ecosystems while simultaneously pointing out the key model developments for capturing complex subarctic processes.

  17. Residence times and age distributions of spring waters at the Semmering catchment area, Eastern Austria, as inferred from tritium, CFCs and stable isotopes.

    Science.gov (United States)

    Han, Liangfeng; Hacker, Peter; Gröning, Manfred

    2007-03-01

    The groundwater system in the mountainous area of Semmering, Austria, was studied by environmental tracers in several karst springs. The tracers used included stable isotopes ((18)O, (2)H), tritium ((3)H) and chlorofluorocarbons (CFCs). The tracers provided valuable information in regard to (1) the mean altitude of the spring catchment areas; (2) the residence time and age distribution of the spring waters; and (3) the interconnection of the springs to a sinkhole. The combination of the stable isotopic data and the topography/geology provided the estimates of the mean altitudes of the catchment areas. Based on the stable isotopic data the recharge temperature of the spring waters was estimated. The smoothing of precipitation's isotopic signal in spring discharge provided information on the minimum transit time of the spring waters. Due to short observation time, (3)H data alone cannot be used for describing the mean residence time of the karst waters. CFCs, though useful in recognizing the co-existence of young (post-1993) water with old (CFC-free) water, could not be used to resolve age distribution models. It is shown in this article, however, that the combined use of tritium and CFCs can provide a better assessment of models to account for different groundwater age distributions. In Appendix A, a simplified method for collecting groundwater samples for the analysis of CFCs is described. The method provides a real facilitation for fieldwork. Test data are given for this sampling method in regard to potential contamination by atmospheric CFCs.

  18. Testing the INCA model in a small agricultural catchment in southern Finland

    Directory of Open Access Journals (Sweden)

    K. Granlund

    2004-01-01

    Full Text Available Nutrient leaching from agricultural production is still recognised as a major environmental problem in Finland. To estimate agricultural nitrogen loading under changing land-use and climate conditions, the Integrated Nitrogen Model for Catchments (INCA was applied in Savijoki, a small (15.4 km2 agricultural catchment, which represents the intensively cultivated areas in south-western Finland. Hydrological calibration and testing of the INCA model was first carried out in Savijoki during 1981–2000. In spite of heterogeneous soil and land-use conditions, INCA was able to reproduce the overall hydrological regime in the stream. The model was calibrated further in respect of nitrogen processes during 1995–2000. The model was able, reasonably well, to simulate the overall annual dynamics of the inorganic N concentrations in the stream water and the annual N export from the catchment. The average simulated NO3-N export was 550 kg N km–2 yr–1 and the observed one (constituting more than half of the annual total N export was 592 kg N km–2 yr–1. For NH4-N, the simulated export was somewhat higher than that measured but NH4-N was only 4% of the total N export. In spite of some underestimation of flow and N concentration during extreme hydrological conditions, the INCA model proved to be a useful tool for analysing flow pattern and inorganic nitrogen leaching in a small agricultural catchment, characterised by a rapid response to rainfall. Keywords: nitrogen, integrated modelling, hydrology, catchment, agriculture

  19. A model for assessing water quality risk in catchments prone to wildfire

    Science.gov (United States)

    Langhans, Christoph; Smith, Hugh; Chong, Derek; Nyman, Petter; Lane, Patrick; Sheridan, Gary

    2017-04-01

    Post-fire debris flows can have erosion rates up to three orders of magnitude higher than background rates. They are major sources of fine suspended sediment, which is critical to the safety of water supply from forested catchments. Fire can cover parts or all of these large catchments and burn severity is often heterogeneous. The probability of spatial and temporal overlap of fire disturbance and rainfall events, and the susceptibility of hillslopes to severe erosion determine the risk to water quality. Here we present a model to calculate recurrence intervals of high magnitude sediment delivery from runoff-generated debris flows to a reservoir in a large catchment (>100 km2) accounting for heterogeneous burn conditions. Debris flow initiation was modelled with indicators of surface runoff and soil surface erodibility. Debris flow volume was calculated with an empirical model, and fine sediment delivery was calculated using simple, expert-based assumptions. In a Monte-Carlo simulation, wildfire was modelled with a fire spread model using historic data on weather and ignition probabilities for a forested catchment in central Victoria, Australia. Multiple high intensity storms covering the study catchment were simulated using Intensity-Frequency-Duration relationships, and the runoff indicator calculated with a runoff model for hillslopes. A sensitivity analysis showed that fine sediment is most sensitive to variables related to the texture of the source material, debris flow volume estimation, and the proportion of fine sediment transported to the reservoir. As a measure of indirect validation, denudation rates of 4.6 - 28.5 mm ka-1 were estimated and compared well to other studies in the region. From the results it was extrapolated that in the absence of fire management intervention the critical sediment concentrations in the studied reservoir could be exceeded in intervals of 18 - 124 years.

  20. A model for assessing water quality risk in catchments prone to wildfire

    Science.gov (United States)

    Langhans, Christoph; Smith, Hugh G.; Chong, Derek M. O.; Nyman, Petter; Lane, Patrick N. J.; Sheridan, Gary J.

    2016-03-01

    Post-fire debris flows can have erosion rates up to three orders of magnitude higher than background rates. They are major sources of fine suspended sediment, which is critical to the safety of water supply from forested catchments. Fire can cover parts or all of these large catchments and burn severity is often heterogeneous. The probability of spatial and temporal overlap of fire disturbance and rainfall events, and the susceptibility of hillslopes to severe erosion determine the risk to water quality. Here we present a model to calculate recurrence intervals of high magnitude sediment delivery from runoff-generated debris flows to a reservoir in a large catchment (>100 km2) accounting for heterogeneous burn conditions. Debris flow initiation was modelled with indicators of surface runoff and soil surface erodibility. Debris flow volume was calculated with an empirical model, and fine sediment delivery was calculated using simple, expert-based assumptions. In a Monte-Carlo simulation, wildfire was modelled with a fire spread model using historic data on weather and ignition probabilities for a forested catchment in central Victoria, Australia. Multiple high intensity storms covering the study catchment were simulated using Intensity-Frequency-Duration relationships, and the runoff indicator calculated with a runoff model for hillslopes. A sensitivity analysis showed that fine sediment is most sensitive to variables related to the texture of the source material, debris flow volume estimation, and the proportion of fine sediment transported to the reservoir. As a measure of indirect validation, denudation rates of 4.6-28.5 mm ka-1 were estimated and compared well to other studies in the region. From the results it was extrapolated that in the absence of fire management intervention the critical sediment concentrations in the studied reservoir could be exceeded in intervals of 18-124 years.

  1. Combining catchment and instream modelling to assess physical habitat quality

    DEFF Research Database (Denmark)

    Olsen, Martin

    observations showed that juvenile trout in stream Ledreborg prefered lower water depths and water velocities than juvenile trout in larger Danish streams, e.g. River Gudenå. Repeated electrofishing in the stream revealed big differences in temporal and spatial distribution of the trouts on the four reaches...... and abundance of trout on the reaches. • Comparison of reference condition minimum run-off and WUA curves suggested that summer low flow were not a limiting factor on the physical habitat quality for juvenile trout under reference conditions. • Habitat hydraulic modelling suggested that stream Ledreborg had...... the best potential physical habitat quality for trout fry and juvenile trout and the lowest potential physical habitat quality for adult trout. This finding supports previous evaluations of the stream as a trout habitat, concluding that stream Ledreborg has very few suitable habitats for adult trout...

  2. Modelling acidification, recovery and target loads for headwater catchments in Nova Scotia, Canada

    Directory of Open Access Journals (Sweden)

    C. J. Whitfield

    2007-01-01

    Full Text Available The response of twenty acid-sensitive headwater catchments in Nova Scotia to acidic deposition was investigated for the period 1850–2100 using a dynamic hydrochemical model (MAGIC: Model of Acidification of Groundwater in Catchments. To ensure robust model simulation, MAGIC was calibrated to the long-term chemical trend in annual lake observations (13–20 years. Model simulations indicated that the surface waters of all twenty catchments acidified to the 1970s but showed subsequent recovery (increases in acid neutralising capacity (ANC and pH as sulphate deposition decreased. However, under proposed future emissions reductions (approximately 50% of current deposition simulated ANC and pH will not return to estimated pre-industrial levels by 2100. An ANC of 20 μmolc L−1 and pH of 5.4 were defined as acceptable chemical thresholds (or critical chemical limits for aquatic organisms in the current study. Under the proposed emissions reductions only one catchment is predicted to remain below the critical limit for ANC by 2100; three additional catchments are predicted to remain below the critical limit for pH. Dynamic models may be used to estimate target loads, i.e., the required deposition reductions to achieve recovery within a given time. Setting target loads at approximately 30% of current depositions would allow three of the four lakes to reach the chemical criteria by 2030. In contrast to the generally good prognosis for surface waters, soils lost an average of 32% of estimated initial base saturation and recovery is estimated to be very slow, averaging 23% lower than pre-acidification levels in 2100.

  3. Application of Tank Model for Predicting Water Balance and Flow Discharge Components of Cisadane Upper Catchment

    Directory of Open Access Journals (Sweden)

    Nana Mulyana Arifjaya

    2012-01-01

    Full Text Available The concept of hydrological tank model was well described into four compartments (tanks. The first tank (tank A comprised of one vertical (qA0 and two lateral (qA1 and qA2 water flow components and tank B comprised of one vertical (qB0 and one lateral (qB1 water flow components. Tank C comprised of one vertical (qC0 and one lateral (qC1 water flow components, whereas tank D comprised of one lateral water flow component (qD1.  These vertical water flows would also contribute to the depletion of water flow in the related tanks but would replenish tanks in the deeper layers. It was assumed that at all lateral water flow components would finally accumulate in one stream, summing-up of the lateral water flow, much or less, should be equal to the water discharge (Qo at specified time concerns. Tank A received precipitation (R and evapo-transpiration (ET which was its gradientof (R-ET over time would become the driving force for the changes of water stored in the soil profiles and thosewater flows leaving the soil layer.  Thus tank model could describe th vertical and horizontal water flow withinthe watershed. The research site was Cisadane Upper Catchment, located at Pasir Buncir Village of CaringinSub-District within the Regency of Bogor in West Java Province.  The elevations ranged 512 –2,235 m above sealevel, with a total drainage area of 1,811.5 ha and total length of main stream of 14,340.7 m.  The land cover wasdominated by  forest  with a total of 1,044.6 ha (57.67%,  upland agriculture with a total of 477.96 ha (26.38%,mixed garden with a total of 92.85 ha(5.13% and semitechnical irigated rice field with a total of 196.09 ha (10,8%.  The soil was classified as hydraquent (96.6% and distropept (3.4%.  Based on the calibration of tank model application in the study area, the resulting coefficient of determination (R2 was 0.72 with model efficiency (NSEof= 0.75, thus tank model could well illustrate the water flow distribution of

  4. Effects of uncertainties in hydrological modelling. A case study of a mountainous catchment in Southern Norway

    Science.gov (United States)

    Engeland, Kolbjørn; Steinsland, Ingelin; Johansen, Stian Solvang; Petersen-Øverleir, Asgeir; Kolberg, Sjur

    2016-05-01

    In this study, we explore the effect of uncertainty and poor observation quality on hydrological model calibration and predictions. The Osali catchment in Western Norway was selected as case study and an elevation distributed HBV-model was used. We systematically evaluated the effect of accounting for uncertainty in parameters, precipitation input, temperature input and streamflow observations. For precipitation and temperature we accounted for the interpolation uncertainty, and for streamflow we accounted for rating curve uncertainty. Further, the effects of poorer quality of precipitation input and streamflow observations were explored. Less information about precipitation was obtained by excluding the nearest precipitation station from the analysis, while reduced information about the streamflow was obtained by omitting the highest and lowest streamflow observations when estimating the rating curve. The results showed that including uncertainty in the precipitation and temperature inputs has a negligible effect on the posterior distribution of parameters and for the Nash-Sutcliffe (NS) efficiency for the predicted flows, while the reliability and the continuous rank probability score (CRPS) improves. Less information in precipitation input resulted in a shift in the water balance parameter Pcorr, a model producing smoother streamflow predictions, giving poorer NS and CRPS, but higher reliability. The effect of calibrating the hydrological model using streamflow observations based on different rating curves is mainly seen as variability in the water balance parameter Pcorr. When evaluating predictions, the best evaluation scores were not achieved for the rating curve used for calibration, but for rating curves giving smoother streamflow observations. Less information in streamflow influenced the water balance parameter Pcorr, and increased the spread in evaluation scores by giving both better and worse scores.

  5. Dynamical process upscaling for deriving catchment scale state variables and constitutive relations for meso-scale process models

    Directory of Open Access Journals (Sweden)

    E. Zehe

    2006-01-01

    Full Text Available In this study we propose an uspcaling approach to derive time series of (a REW scale state variables, and (b effective REW scale soil hydraulic functions to test and parameterise models based on the REW approach. To this end we employed a physically based hydrological model, that represents the typical patterns and structures in the study catchment, and has previously been shown to reproduce observed runoff response and state dynamics well. This landscape- and process-compatible model is used to simulate numerical drainage and wetting experiments. The effective soil water retention curve and soil hydraulic conductivity curve are derived using the spatially averaged saturation and capillary pressure as well as averaged fluxes. When driven with observed boundary conditions during a one year simulation the model is used to estimate how the spatial pattern of soil moisture evolved during this period in the catchment. The time series of the volume integrated soil moisture is deemed as best estimate for the average catchment scale soil moisture. The approach is applied to the extensively monitored Weiherbach catchment in Germany. A sensitivity analysis showed that catchment scale model structures different from the landscape- and process compatible one yielded different times series of average catchment scale soil moisture and where not able to reproduce the observed rainfall runoff response. Hence, subscale typical heterogeneity leaves a clear fingerprint in the time series of average catchment scale saturation. In case of the Weiherbach catchment local scale heterogeneity of ks could be neglected and a simple representation of the typical hillslope scale patterns of soil types and macroporosity was sufficient for obtaining effective REW scale soil hydraulic functions. Both the effective soil hydraulic functions and time series of catchment scale saturation turned out to be useful to parameterise and test the CREW model, which is based on the REW

  6. HBV light - A user-friendly catchment-runoff-model software

    Science.gov (United States)

    Seibert, J.; Vis, M.; Käser, D.

    2012-04-01

    Conceptual models are frequently used for catchment hydrology studies. Here we present a new version of the HBV model, which has been programmed in Visual Basic .NET. This software provides a user-friendly version which is especially useful for education. Different functionalities like an automatic calibration and the possibility to perform Monte Carlo runs make the software also interesting for research projects. Furthermore, a command line version is suitable for automating modeling procedures and for coupling with software such as PEST.

  7. Understanding hydrological flow paths in conceptual catchment models using uncertainty and sensitivity analysis

    Science.gov (United States)

    Mockler, Eva M.; O'Loughlin, Fiachra E.; Bruen, Michael

    2016-05-01

    Increasing pressures on water quality due to intensification of agriculture have raised demands for environmental modeling to accurately simulate the movement of diffuse (nonpoint) nutrients in catchments. As hydrological flows drive the movement and attenuation of nutrients, individual hydrological processes in models should be adequately represented for water quality simulations to be meaningful. In particular, the relative contribution of groundwater and surface runoff to rivers is of interest, as increasing nitrate concentrations are linked to higher groundwater discharges. These requirements for hydrological modeling of groundwater contribution to rivers initiated this assessment of internal flow path partitioning in conceptual hydrological models. In this study, a variance based sensitivity analysis method was used to investigate parameter sensitivities and flow partitioning of three conceptual hydrological models simulating 31 Irish catchments. We compared two established conceptual hydrological models (NAM and SMARG) and a new model (SMART), produced especially for water quality modeling. In addition to the criteria that assess streamflow simulations, a ratio of average groundwater contribution to total streamflow was calculated for all simulations over the 16 year study period. As observations time-series of groundwater contributions to streamflow are not available at catchment scale, the groundwater ratios were evaluated against average annual indices of base flow and deep groundwater flow for each catchment. The exploration of sensitivities of internal flow path partitioning was a specific focus to assist in evaluating model performances. Results highlight that model structure has a strong impact on simulated groundwater flow paths. Sensitivity to the internal pathways in the models are not reflected in the performance criteria results. This demonstrates that simulated groundwater contribution should be constrained by independent data to ensure results

  8. Conditioning rainfall-runoff model parameters for ungauged catchments and land management impacts analysis

    Directory of Open Access Journals (Sweden)

    N. Bulygina

    2009-06-01

    Full Text Available Data scarcity and model over-parameterisation, leading to model equifinality and large prediction uncertainty, are common barriers to effective hydrological modelling. The problem can be alleviated by constraining the prior parameter space using parameter regionalisation. A common basis for regionalisation in the UK is the HOST database which provides estimates of hydrological indices for different soil classifications. In our study, Base Flow Index is estimated from the HOST database and the power of this index for constraining the parameter space is explored. The method is applied to a highly discretised distributed model of a 12.5 km2 upland catchment in Wales. To assess probabilistic predictions against flow observations, a probabilistic version of the Nash-Sutcliffe efficiency is derived. For six flow gauges with reliable data, this efficiency ranged between 0.70 and 0.81, and inspection of the results shows that the model explains the data well. Knowledge of how Base Flow Index and interception losses may change under future land use management interventions was then used to further condition the model. Two interventions are considered: afforestation of grazed areas, and soil degradation associated with increased grazing intensity. Afforestation leads to median reduction in modelled runoff volume of 24% over the simulated 3 month period; and a median peak flow reduction ranging from 12 to 15% over the six gauges for the largest simulated event. Uncertainty in all results is low compared to prior uncertainty and it is concluded that using Base Flow Index estimated from HOST is a simple and potentially powerful method of conditioning the parameter space under current and future land management.

  9. Modelling daily sediment yield from a meso-scale catchment, a case study in SW Poland

    Energy Technology Data Exchange (ETDEWEB)

    Keesstra, S. D.; Schoorl, J.; Temme, A. J. A. M.

    2009-07-01

    For management purposes it is important to be able to assess the sediment yield of a catchment. however, at this moment models designed for estimating sediment yield are only capable to give either very detailed storm-based information or year averages. The storm-based models require input data that are not available for most catchment. However, models that estimate yearly averages, ignore a lot of other detailed information, like daily discharge and precipitation data. There are currently no models available that model sediment yield on the temporal scale of one day and the spatial scale of a meso-scale catchment, without making use of very detailed input data. To fill this scientific and management gap, landscape evolution model LAPSUS has been adapted to model sediment yield on a daily basis. This model has the water balance as a base. To allow calibration with the discharge at the outlet, a subsurface flow module has been added to the model. (Author) 12 refs.

  10. Modelling mean transit time of stream base flow during tropical cyclone rainstorm in a steep relief forested catchment

    Science.gov (United States)

    Lee, Jun-Yi; Huang, -Chuan, Jr.

    2017-04-01

    Mean transit time (MTT) is one of the of fundamental catchment descriptors to advance understanding on hydrological, ecological, and biogeochemical processes and improve water resources management. However, there were few documented the base flow partitioning (BFP) and mean transit time within a mountainous catchment in typhoon alley. We used a unique data set of 18O isotope and conductivity composition of rainfall (136 mm to 778 mm) and streamflow water samples collected for 14 tropical cyclone events (during 2011 to 2015) in a steep relief forested catchment (Pinglin, in northern Taiwan). A lumped hydrological model, HBV, considering dispersion model transit time distribution was used to estimate total flow, base flow, and MTT of stream base flow. Linear regression between MTT and hydrometric (precipitation intensity and antecedent precipitation index) variables were used to explore controls on MTT variation. Results revealed that both the simulation performance of total flow and base flow were satisfactory, and the Nash-Sutcliffe model efficiency coefficient of total flow and base flow was 0.848 and 0.732, respectively. The event magnitude increased with the decrease of estimated MTTs. Meanwhile, the estimated MTTs varied 4-21 days with the increase of BFP between 63-92%. The negative correlation between event magnitude and MTT and BFP showed the forcing controls the MTT and BFP. Besides, a negative relationship between MTT and the antecedent precipitation index was also found. In other words, wetter antecedent moisture content more rapidly active the fast flow paths. This approach is well suited for constraining process-based modeling in a range of high precipitation intensity and steep relief forested environments.

  11. Effect of the spatial distribution of physical aquifer properties on water table depth and stream discharge in a headwater catchment

    Directory of Open Access Journals (Sweden)

    C. Gascuel-Odoux

    2009-11-01

    Full Text Available Water table depth and its dynamics is often poorly predicted upslope despite they control both water transit time within the catchment and solute fluxes at the catchment outlet. The paper analyses how relaxing the assumption of lateral homogeneity of physical properties can improve simulations of water table depth and dynamics. Four different spatial models relating of saturated hydraulic conductivity to topography have been tested: a simple linear relationship, a linear relationship with two topographic indexes, two domains with a transitional area. The Hill-Vi model has been modified to test these hypotheses. The studied catchment (Kervidy-Naizin, western France is underlain by schist crystalline bedrock. A shallow and perennial groundwater highly reactive to rainfall events mainly develops in the weathered saprolite layer. The results indicate that 1 discharge and the water table in the riparian zone are similarly predicted with the four models, 2 distinguishing two domains constitutes the best model and slightly improves prediction of the water table upslope, and 3 including spatial variations in the other parameters such as porosity or rate of hydraulic conductivity decrease with depth does not improve the results. These results underline the necessity of better investigation of upslope areas in hillslope hydrology.

  12. Modelling the water balance of a mesoscale catchment basin using remotely sensed land cover data

    Science.gov (United States)

    Montzka, Carsten; Canty, Morton; Kunkel, Ralf; Menz, Gunter; Vereecken, Harry; Wendland, Frank

    2008-05-01

    SummaryHydrological modelling of mesoscale catchments is often adversely affected by a lack of adequate information about specific site conditions. In particular, digital land cover data are available from data sets which were acquired on a European or a national scale. These data sets do not only exhibit a restricted spatial resolution but also a differentiation of crops and impervious areas which is not appropriate to the needs of mesoscale hydrological models. In this paper, the impact of remote sensing data on the reliability of a water balance model is investigated and compared to model results determined on the basis of CORINE (Coordination of Information on the Environment) Land Cover as a reference. The aim is to quantify the improved model performance achieved by an enhanced land cover representation and corresponding model modifications. Making use of medium resolution satellite imagery from SPOT, LANDSAT ETM+ and ASTER, detailed information on land cover, especially agricultural crops and impervious surfaces, was extracted over a 5-year period (2000-2004). Crop-specific evapotranspiration coefficients were derived by using remote sensing data to replace grass reference evapotranspiration necessitated by the use of CORINE land cover for rural areas. For regions classified as settlement or industrial areas, degrees of imperviousness were derived. The data were incorporated into the hydrological model GROWA (large-scale water balance model), which uses an empirical approach combining distributed meteorological data with distributed site parameters to calculate the annual runoff components. Using satellite imagery in combination with runoff data from gauging stations for the years 2000-2004, the actual evapotranspiration calculation in GROWA was methodologically extended by including empirical crop coefficients for actual evapotranspiration calculations. While GROWA originally treated agricultural areas as homogeneous, now a consideration and differentiation

  13. Water balance modeling of Upper Blue Nile catchments using a top-down approach

    Directory of Open Access Journals (Sweden)

    S. Tekleab

    2011-07-01

    Full Text Available The water balances of twenty catchments in the Upper Blue Nile basin have been analyzed using a top-down modeling approach based on Budyko's hypotheses. The objective of this study is to obtain better understanding of water balance dynamics of upper Blue Nile catchments on annual and monthly time scales and on a spatial scale of meso scale to large scale. The water balance analysis using a Budyko-type curve at annual scale reveals that the aridity index does not exert a first order control in most of the catchments. This implies the need to increase model complexity to monthly time scale to include the effects of seasonal soil moisture dynamics. The dynamic water balance model used in this study predicts the direct runoff and other processes based on the limit concept; i.e. for dry environments since rainfall amount is small, the aridity index approaches to infinity or equivalently evaporation approaches rainfall and for wet environments where the rainfall amount is large, the aridity index approaches to zero and actual evaporation approaches the potential evaporation. The uncertainty of model parameters has been assessed using the GLUE (Generalized Likelihood Uncertainty Estimation methodology. The results show that the majority of the parameters are reasonably well identifiable. However, the baseflow recession constant was poorly identifiable. Parameter uncertainty and model structural errors could be the reason for the poorly identifiable parameter. Moreover, a multi-objective model calibration strategy has been employed to emphasize the different aspects of the hydrographs on low and high flows.

    The model has been calibrated and validated against observed streamflow time series and it shows good performance for the twenty study catchments in the upper Blue Nile. During the calibration period (1995–2000 the Nash and Sutcliffe efficiency (E NS for monthly flow prediction varied between 0.52 to 0.93 (dominated by

  14. How does spatial variability of climate affect catchment streamflow predictions?

    Science.gov (United States)

    Spatial variability of climate can negatively affect catchment streamflow predictions if it is not explicitly accounted for in hydrologic models. In this paper, we examine the changes in streamflow predictability when a hydrologic model is run with spatially variable (distribute...

  15. Bed load size distribution and flow conditions in a high mountain catchment of Central Pyrenees

    Directory of Open Access Journals (Sweden)

    Martínez-Castroviejo, Ricardo

    1990-06-01

    Full Text Available The bed load size distribution caused by different types of flow are compared in a high mountain catchment located in the upper Gallego river basin (Central Spanish’ Pyrenees. Three kinds of hydrologic events could be defined: those triggered by heavy autumn rainfalls, those originated by isolated summer rainstorms and those promoted by snowmelting. Each one is characterized by a peculiar bed load size distribution. Thus, it could be demonstrated that the coarser fractions, above 30 mm in diameter, are up to six times more abundant, in percentage of total weight, in transports caused by heavy rainfalls than in the material collected after snowmelt flows. In its turn, bed load mobilized by snowmelt flows is mainly composed by medium and fine gravel, from 2 to 8 mm. These may amount up to 60 % of total weight of bed load. The reasons for these so different size distributions are discussed.

    [es] En una cuenca de alta montaña localizada en el alto valle del río Gallego (Pirineo central se comparan las distribuciones por tamaños de los acarreos movilizados por diferentes tipos de caudal. Tres tipos de eventos hidrológicos han podido ser caracterizados: los ocasionados por intensas lluvias de otoño, los originados por tormentas estivales aisladas y los producidos por la fusión de la nieve acumulada durante el invierno. Se concluye que cada uno de ellos lleva asociada una distribución por tamaños típica de la carga de fondo. Así, se ha comprobado que las fracciones más gruesas consideradas -superiores a los 30 mm de diámetro- son hasta seis veces más abundantes -en porcentaje sobre el peso total- en las exportaciones causadas por lluvias de gran intensidad que en las generadas por caudales de fusión. A su vez, las descargas ocasionadas por la fusión arrastran principalmente gravas de calibre medio y fino -entre 2y8 mm- que llegan a suponer el 60 % en peso del volumen movilizado. Este artículo discute las razones que provocan

  16. Spatialised fate factors for nitrate in catchments: modelling approach and implication for LCA results.

    Science.gov (United States)

    Basset-Mens, Claudine; Anibar, Lamiaa; Durand, Patrick; van der Werf, Hayo M G

    2006-08-15

    The challenge for environmental assessment tools, such as Life Cycle Assessment (LCA) is to provide a holistic picture of the environmental impacts of a given system, while being relevant both at a global scale, i.e., for global impact categories such as climate change, and at a smaller scale, i.e., for regional impact categories such as aquatic eutrophication. To this end, the environmental mechanisms between emission and impact should be taken into account. For eutrophication in particular, which is one of the main impacts of farming systems, the fate factor of eutrophying pollutants in catchments, and particularly of nitrate, reflects one of these important and complex environmental mechanisms. We define this fate factor as: the ratio of the amount of nitrate at the outlet of the catchment over the nitrate emitted from the catchment's soils. In LCA, this fate factor is most often assumed equal to 1, while the observed fate factor is generally less than 1. A generic approach for estimating the range of variation of nitrate fate factors in a region of intensive agriculture was proposed. This approach was based on the analysis of different catchment scenarios combining different catchment types and different effective rainfalls. The evolution over time of the nitrate fate factor as well as the steady state fate factor for each catchment scenario was obtained using the INCA simulation model. In line with the general LCA model, the implications of the steady state fate factors for nitrate were investigated for the eutrophication impact result in the framework of an LCA of pig production. A sensitivity analysis to the fraction of nitrate lost as N(2)O was presented for the climate change impact category. This study highlighted the difference between the observed fate factor at a given time, which aggregates both storage and transformation processes and a "steady state fate factor", specific to the system considered. The range of steady state fate factors obtained for

  17. Physically based modeling in catchment hydrology at 50: Survey and outlook

    Science.gov (United States)

    Paniconi, Claudio; Putti, Mario

    2015-09-01

    Integrated, process-based numerical models in hydrology are rapidly evolving, spurred by novel theories in mathematical physics, advances in computational methods, insights from laboratory and field experiments, and the need to better understand and predict the potential impacts of population, land use, and climate change on our water resources. At the catchment scale, these simulation models are commonly based on conservation principles for surface and subsurface water flow and solute transport (e.g., the Richards, shallow water, and advection-dispersion equations), and they require robust numerical techniques for their resolution. Traditional (and still open) challenges in developing reliable and efficient models are associated with heterogeneity and variability in parameters and state variables; nonlinearities and scale effects in process dynamics; and complex or poorly known boundary conditions and initial system states. As catchment modeling enters a highly interdisciplinary era, new challenges arise from the need to maintain physical and numerical consistency in the description of multiple processes that interact over a range of scales and across different compartments of an overall system. This paper first gives an historical overview (past 50 years) of some of the key developments in physically based hydrological modeling, emphasizing how the interplay between theory, experiments, and modeling has contributed to advancing the state of the art. The second part of the paper examines some outstanding problems in integrated catchment modeling from the perspective of recent developments in mathematical and computational science.

  18. Climate model validation and selection for hydrological applications in representative Mediterranean catchments

    Directory of Open Access Journals (Sweden)

    R. Deidda

    2013-07-01

    Full Text Available This paper discusses the relative performance of several climate models in providing reliable forcing for hydrological modeling in six representative catchments in the Mediterranean region. We consider 14 Regional Climate Models (RCMs, from the EU-FP6 ENSEMBLES project, run for the A1B emission scenario on a common 0.22-degree (about 24 km rotated grid over Europe and the Mediterranean. In the validation period (1951 to 2010 we consider daily precipitation and surface temperatures from the E-OBS dataset, available from the ENSEMBLES project and the data providers in the ECA&D project. Our primary objective is to rank the 14 RCMs for each catchment and select the four best performing ones to use as common forcing for hydrological models in the six Mediterranean basins considered in the EU-FP7 CLIMB project. Using a common suite of 4 RCMs for all studied catchments reduces the (epistemic uncertainty when evaluating trends and climate change impacts in the XXI century. We present and discuss the validation setting, as well as the obtained results and, to some detail, the difficulties we experienced when processing the data. In doing so we also provide useful information and hint for an audience of researchers not directly involved in climate modeling, but interested in the use of climate model outputs for hydrological modeling and, more in general, climate change impact studies in the Mediterranean.

  19. Simulation of stormwater quality in an urban catchment using the Stormwater Management Model (SWMM)

    OpenAIRE

    2014-01-01

    In the face of climate change, population growth and urbanization an understanding of stormwater quality processes and their prediction in urban areas are essential to make good use of stormwater and to minimize its detrimental impacts on the population and the environment. In this study a stormwater quality model calibration was conducted using the Stormwater Management Model (SWMM) for an urban catchment in Lahti, Finland by utilizing rainfall, runoff and turbidity data from the catchme...

  20. Runoff modelling in glacierized Central Asian catchments for present-day and future climate

    OpenAIRE

    Hagg, Wilfried; Braun, L. N.; Weber, M.; Becht, M.

    2006-01-01

    A conceptual precipitation–runoff model was applied in five glacierized catchments in Central Asia. The model, which was first developed and applied in the Alps, works on a daily time step and yields good results in the more continental climate of the Tien Shan mountains for present-day climate conditions. Runoff scenarios for different climates (doubling of CO2) and glacierization conditions predict an increased flood risk as a first stage and a more complex picture after a complete glacier ...

  1. Distributed generation systems model

    Energy Technology Data Exchange (ETDEWEB)

    Barklund, C.R.

    1994-12-31

    A slide presentation is given on a distributed generation systems model developed at the Idaho National Engineering Laboratory, and its application to a situation within the Idaho Power Company`s service territory. The objectives of the work were to develop a screening model for distributed generation alternatives, to develop a better understanding of distributed generation as a utility resource, and to further INEL`s understanding of utility concerns in implementing technological change.

  2. Modelled seasonal forecasts of snow water equivalent and runoff in alpine catchments

    Science.gov (United States)

    Förster, Kristian; Hanzer, Florian; Schöber, Johannes; Huttenlau, Matthias; Achleitner, Stefan; Strasser, Ulrich

    2016-04-01

    Seasonal forecasts of water balance components are becoming increasingly important for hydrological applications. These forecasts are typically derived from coupled atmosphere-ocean climate models, which enable physically based seasonal forecasts. In mountainous regions, however, topography is complex whilst typical spatial resolutions of the climate models are still comparably coarse, i.e in the data, ridges and valleys are not represented with sufficient accuracy. Therefore, seasonal predictions of atmospheric variables require consideration of representative gradients. We present first results of seasonal forecasts and re-forecasts processed by the NCEP (National Centers for Environmental Prediction) Climate Forecast System version 2 (CFSv2). These are prepared for monthly time steps in order to be used for ensemble runs of water balance simulation using the Alpine Water balance And Runoff Estimation model (AWARE). This model has been designed for monthly seasonal predictions in ice- and snowmelt dominated catchments. The study area is the Inn catchment in Tyrol/Austria, including its headwaters in Switzerland. Results are evaluated for both anomalies of meteorological input data (temperature and precipitation), as well as balance components including snow water equivalent and runoff, both simulated with AWARE. Based on model skill evaluations derived from forecasts and observations, the model chain CFSv2 - AWARE proves helpful to analyse possible future hydrological system states of mountainous catchments with emphasis on spatio-temporal snow cover evolution.

  3. Modelling the effects of land use changes on the streamflow of a peri-urban catchment in central Portugal

    Science.gov (United States)

    Hävermark, Saga; Santos Ferreira, Carla Sofia; Kalantari, Zahra; Di Baldassarre, Giuliano

    2016-04-01

    Many river basis around the world are rapidly changing together with societal development. Such developments may involve changes in land use, which in turn affect the surrounding environment in various ways. Since the start of industrialisation, the urban areas have extended worldwide. Urbanization can influence hydrological processes by decreasing evapotranspiration, infiltration and groundwater recharge as well as increasing runoff and overland flow. It is therefore of uttermost importance to understand the relationship between land use and hydrology. Although several studies have been investigating the impacts of urbanization on streamflow over the last decades, less is known on how urbanization affects hydrological processes in peri-urban areas, characterized by a complex mosaic of different land uses. This study aimed to model the impact of land use changes, specifically urbanization and commercial forest plantation, on the hydrological responses of the small Ribeira dos Covões peri-urban catchment (6,2 km2) located in central Portugal. The catchment has undergone rapid land use changes between 1958 and 2012 associated with the conversion of agricultural fields (cover area decreased from 48% to 4%) into woodland and urban areas, which increased from 44% to 56% and from 8% to 40%, respectively. For the study, the fully-distributed, physically-based modelling system MIKE SHE was used. The model was designed to examine both how past land use changes might have affected the streamflow and to investigate the impacts on hydrology of possible future scenarios, including a 50 %, 60 % and 70 % urban cover. To this end, a variety of data including daily rainfall since 1958 and forward, daily potential evapotranspiration from 2009 to 2013, monthly temperature averages from 1971 to 2013, land use for the years 1958, 1973, 1979, 1990, 1995, 2002, 2007 and 2012, streamflow from the hydrological years 2008 to 2013, catchment topography and soil types were used. The model

  4. Predictions of rainfall-runoff response and soil moisture dynamics in a microscale catchment using the CREW model

    Directory of Open Access Journals (Sweden)

    H. Lee

    2006-07-01

    Full Text Available Predictions of catchment hydrology have been performed generally using either physically based, distributed models or conceptual lumped or semi-distributed models. In recognition of the disadvantages of using either of these modeling approaches, namely, detailed data requirements in the case of distributed modeling, and lack of physical basis of conceptual/lumped model parameters, Reggiani et al. (1998, 1999 derived, from first principles and in a general manner, the balance equations for mass, momentum and energy at what they called the Representative Elementary Watershed (or REW scale. However, the mass balance equations of the REW approach include mass exchange flux terms which must be defined externally before their application to real catchments. Developing physically reasonable "closure relations'' for these mass exchange flux terms is a crucial pre-requisite for the success of the REW approach. As a guidance to the development of closure relations expressing mass exchange fluxes as functions of relevant state variables in a physically reasonable way, and in the process effectively parameterizing the effects of sub-grid or sub-REW heterogeneity of catchment physiographic properties on these mass exchange fluxes, this paper considers four different approaches, namely the field experimental approach, a theoretical/analytical approach, a numerical approach, and a hybrid approach combining one or more of the above. Based on the concept of the scaleway (Vogel and Roth, 2003 and the disaggregation-aggregation approach (Viney and Sivapalan, 2004, and using the data set from Weiherbach catchment in Germany, closure relations for infiltration, exfiltration and groundwater recharge were derived analytically, or on theoretical grounds, while numerical experiments with a detailed fine-scale, distributed model, CATFLOW, were used to obtain the closure relationship for seepage outflow. The detailed model, CATFLOW, was also used to derive REW

  5. Carbon budget estimation of a subarctic catchment using a dynamic ecosystem model at high spatial resolution

    Science.gov (United States)

    Tang, J.; Miller, P. A.; Persson, A.; Olefeldt, D.; Pilesjo, P.; Heliasz, M.; Jackowicz-Korczynski, M.; Yang, Z.; Smith, B.; Callaghan, T. V.; Christensen, T. R.

    2015-05-01

    A large amount of organic carbon is stored in high-latitude soils. A substantial proportion of this carbon stock is vulnerable and may decompose rapidly due to temperature increases that are already greater than the global average. It is therefore crucial to quantify and understand carbon exchange between the atmosphere and subarctic/arctic ecosystems. In this paper, we combine an Arctic-enabled version of the process-based dynamic ecosystem model, LPJ-GUESS (version LPJG-WHyMe-TFM) with comprehensive observations of terrestrial and aquatic carbon fluxes to simulate long-term carbon exchange in a subarctic catchment at 50 m resolution. Integrating the observed carbon fluxes from aquatic systems with the modeled terrestrial carbon fluxes across the whole catchment, we estimate that the area is a carbon sink at present and will become an even stronger carbon sink by 2080, which is mainly a result of a projected densification of birch forest and its encroachment into tundra heath. However, the magnitudes of the modeled sinks are very dependent on future atmospheric CO2 concentrations. Furthermore, comparisons of global warming potentials between two simulations with and without CO2 increase since 1960 reveal that the increased methane emission from the peatland could double the warming effects of the whole catchment by 2080 in the absence of CO2 fertilization of the vegetation. This is the first process-based model study of the temporal evolution of a catchment-level carbon budget at high spatial resolution, including both terrestrial and aquatic carbon. Though this study also highlights some limitations in modeling subarctic ecosystem responses to climate change, such as aquatic system flux dynamics, nutrient limitation, herbivory and other disturbances, and peatland expansion, our study provides one process-based approach to resolve the complexity of carbon cycling in subarctic ecosystems while simultaneously pointing out the key model developments for capturing

  6. An interactive modelling tool for understanding hydrological processes in lowland catchments

    Science.gov (United States)

    Brauer, Claudia; Torfs, Paul; Uijlenhoet, Remko

    2016-04-01

    Recently, we developed the Wageningen Lowland Runoff Simulator (WALRUS), a rainfall-runoff model for catchments with shallow groundwater (Brauer et al., 2014ab). WALRUS explicitly simulates processes which are important in lowland catchments, such as feedbacks between saturated and unsaturated zone and between groundwater and surface water. WALRUS has a simple model structure and few parameters with physical connotations. Some default functions (which can be changed easily for research purposes) are implemented to facilitate application by practitioners and students. The effect of water management on hydrological variables can be simulated explicitly. The model description and applications are published in open access journals (Brauer et al, 2014). The open source code (provided as R package) and manual can be downloaded freely (www.github.com/ClaudiaBrauer/WALRUS). We organised a short course for Dutch water managers and consultants to become acquainted with WALRUS. We are now adapting this course as a stand-alone tutorial suitable for a varied, international audience. In addition, simple models can aid teachers to explain hydrological principles effectively. We used WALRUS to generate examples for simple interactive tools, which we will present at the EGU General Assembly. C.C. Brauer, A.J. Teuling, P.J.J.F. Torfs, R. Uijlenhoet (2014a): The Wageningen Lowland Runoff Simulator (WALRUS): a lumped rainfall-runoff model for catchments with shallow groundwater, Geosci. Model Dev., 7, 2313-2332. C.C. Brauer, P.J.J.F. Torfs, A.J. Teuling, R. Uijlenhoet (2014b): The Wageningen Lowland Runoff Simulator (WALRUS): application to the Hupsel Brook catchment and Cabauw polder, Hydrol. Earth Syst. Sci., 18, 4007-4028.

  7. Identifying sources of acidity and spatial distribution of acid sulfate soils in the Anglesea River catchment, southern Australia

    Science.gov (United States)

    Wong, Vanessa; Yau, Chin; Kennedy, David

    2015-04-01

    Globally, coastal and estuarine floodplains are frequently underlain by sulfidic sediments. When exposed to oxygen, sulfidic sediments oxidise to form acid sulfate soils, adversely impacting on floodplain health and adjacent aquatic ecoystems. In eastern Australia, our understanding of the formation of these coastal and estuarine floodplains, and hence, spatial distribution of acid sulfate soils, is relatively well established. These soils have largely formed as a result of sedimentation of coastal river valleys approximately 6000 years BP when sea levels were one to two metres higher. However, our understanding of the evolution of estuarine systems and acid sulfate soil formation, and hence, distribution, in southern Australia remains limited. The Anglesea River, in southern Australia, is subjected to frequent episodes of poor water quality and low pH resulting in closure of the river and, in extreme cases, large fish kill events. This region is heavily reliant on tourism and host to a number of iconic features, including the Great Ocean Road and Twelve Apostles. Poor water quality has been linked to acid leakage from mining activities and Tertiary-aged coal seams, peat swamps and acid sulfate soils in the region. However, our understanding of the sources of acidity and distribution of acid sulfate soils in this region remains poor. In this study, four sites on the Anglesea River floodplain were sampled, representative of the main vegetation communities. Peat swamps and intertidal marshes were both significant sources of acidity on the floodplain in the lower catchment. However, acid neutralising capacity provided by carbonate sands suggests that there are additional sources of acidity higher in the catchment. This pilot study has highlighted the complexity in the links between the floodplain, upper catchment and waterways with further research required to understand these links for targeted acid management strategies.

  8. Multi-criteria assessment of the Representative Elementary Watershed approach on the Donga catchment (Benin using a downward approach of model complexity

    Directory of Open Access Journals (Sweden)

    N. Varado

    2006-01-01

    Full Text Available This study is part of the AMMA - African Multidisciplinary Monsoon Analysis- project and aims at a better understanding and modelling of the Donga catchment (580 km2, Benin behaviour in order to determine its spatially distributed water balance. For this purpose, we applied the REW concept proposed by Reggiani et al. (1998, 1999, which allows the description of the main local processes at the sub-watershed scale. Such distributed hydrological models, which represent hydrological processes at various scales, should be evaluated not only on the discharge at the outlet but also on each of the represented processes and in several points of the catchment. This multi-criteria approach is required in order to assess the global behaviour of hydrological models. We applied such multi-criteria strategy to the Donga catchment (586 km2, in Benin. The work was supported by an observation set up, undertaken since 1998 consisting in a network of 20 rain gauges, an automatic meteorological station, 6 discharge stations and 18 wells. The main goal of this study was to assess the model's ability to reproduce the discharge at the outlet, the water table dynamics in several points of the catchment and the vadose zone dynamics at the sub-catchment scale. We tested two spatial discretisations of increasing resolution. To test the internal structure of the model, we looked at its ability to represent also the discharge at intermediate stations. After adjustment of soil parameters, the model is shown to accurately represent discharge down to a drainage area of 100 km2, whereas poorer simulation is achieved on smaller catchments. We introduced the spatial variability of rainfall by distributing the daily rainfall over the REW and obtained a very low sensitivity of the model response to this variability. Simulation of groundwater levels was poor and our results, in conjunction with new data available at the local scale, suggest that the representation of the processes

  9. Multi-response calibration of a conceptual hydrological model in the semiarid catchment of Wadi al Arab, Jordan

    Science.gov (United States)

    Rödiger, T.; Geyer, S.; Mallast, U.; Merz, R.; Krause, P.; Fischer, C.; Siebert, C.

    2014-02-01

    A key factor for sustainable management of groundwater systems is the accurate estimation of groundwater recharge. Hydrological models are common tools for such estimations and widely used. As such models need to be calibrated against measured values, the absence of adequate data can be problematic. We present a nested multi-response calibration approach for a semi-distributed hydrological model in the semi-arid catchment of Wadi al Arab in Jordan, with sparsely available runoff data. The basic idea of the calibration approach is to use diverse observations in a nested strategy, in which sub-parts of the model are calibrated to various observation data types in a consecutive manner. First, the available different data sources have to be screened for information content of processes, e.g. if data sources contain information on mean values, spatial or temporal variability etc. for the entire catchment or only sub-catchments. In a second step, the information content has to be mapped to relevant model components, which represent these processes. Then the data source is used to calibrate the respective subset of model parameters, while the remaining model parameters remain unchanged. This mapping is repeated for other available data sources. In that study the gauged spring discharge (GSD) method, flash flood observations and data from the chloride mass balance (CMB) are used to derive plausible parameter ranges for the conceptual hydrological model J2000g. The water table fluctuation (WTF) method is used to validate the model. Results from modelling using a priori parameter values from literature as a benchmark are compared. The estimated recharge rates of the calibrated model deviate less than ±10% from the estimates derived from WTF method. Larger differences are visible in the years with high uncertainties in rainfall input data. The performance of the calibrated model during validation produces better results than applying the model with only a priori parameter

  10. Estimation of Catchment Transit Time in Fuji River Basin by using an improved Tank model

    Science.gov (United States)

    Wenchao, M.; Yamanaka, T.; Wakiyama, Y.; Wang, P.

    2013-12-01

    As an important parameter that reflects the characteristics of catchments, the catchment transit time (CTT) has been given much more widely attentions especially in recent years. The CTT is defined as the time water spends travelling through a catchment to the stream network [1], and it describes how catchments retain and release water and solutes and thus control geochemical and biogeochemical cycling and contamination persistence [2]. The objectives of the present study are to develop a new approach for estimating CTT without prior information on such TTD functions and to apply it to the Fuji River basin in the Central Japan Alps Region. In this study, an improved Tank model was used to compute mean CTT and TTD functions simultaneously. It involved water fluxes and isotope mass balance. Water storage capacity in the catchment, which strongly affects CTT, is reflected in isotope mass balance more sensitively than in water fluxes. A model calibrated with observed discharge and isotope data is used for virtual age tracer computation to estimate CTT. This model does not only consider the hydrological data and physical process of the research area but also reflects the actual TTD with considering the geological condition, land use and the other catchment-hydrological conditions. For the calibration of the model, we used river discharge record obtained by the Ministry of Land, Infrastructure and Transportation, and are collecting isotope data of precipitation and river waters monthly or semi-weekly. Three sub-catchments (SC1~SC3) in the Fuji River basin was selected to test the model with five layers: the surface layer, upper-soil layer, lower-soil layer, groundwater aquifer layer and bedrock layer (Layer 1- Layer 5). The evaluation of the model output was assessed using Nash-Sutcliffe efficiency (NSE), root mean square error-observations standard deviation ratio (RSR), and percent bias (PBIAS). Using long time-series of discharge records for calibration, the simulated

  11. Suspended sediment flux modeling with artificial neural network: An example of the Longchuanjiang River in the Upper Yangtze Catchment, China

    Science.gov (United States)

    Zhu, Yun-Mei; Lu, X. X.; Zhou, Yue

    2007-02-01

    Artificial neural network (ANN) was used to model the monthly suspended sediment flux in the Longchuanjiang River, the Upper Yangtze Catchment, China. The suspended sediment flux was related to the average rainfall, temperature, rainfall intensity and water discharge. It is demonstrated that ANN is capable of modeling the monthly suspended sediment flux with fairly good accuracy when proper variables and their lag effect on the suspended sediment flux are used as inputs. Compared with multiple linear regression and power relation models, ANN can generate a better fit under the same data requirement. In addition, ANN can provide more reasonable predictions for extremely high or low values, because of the distributed information processing system and the nonlinear transformation involved. Compared with the ANNs that use the values of the dependent variable at previous time steps as inputs, the ANNs established in this research with only climate variables have an advantage because it can be used to assess hydrological responses to climate change.

  12. Modelling the impact of soakaway retrofits on combined sewage overflows in a 3km2 urban catchment in Copenhagen, Denmark

    DEFF Research Database (Denmark)

    Roldin, Maria Kerstin; Fryd, Ole; Jeppesen, Jan;

    2012-01-01

    -step approach that employed GIS analyses and physically distributed, dynamic pipe flow modelling in an iterative manner, this study estimates the impact of infiltration on combined sewage overflows (CSOs) in a 3km2 urban catchment in Copenhagen. The first step was the creation of a baseline scenario. The second...... a more realistic scenario where only 8% of the impervious area was connected to soakaways and the reduction in CSO volume was 24%. The potential and realistic scenarios were modelled both with hydraulic coupling between soakaway and sewer, and as fully disconnected. Results show that infiltration...... is constrained mainly by the quality of the stormwater runoff from roads and limited land availability in the potential infiltration scenario, and by low-permeable soils and a problematically high groundwater level in the realistic infiltration scenario. The hydraulically coupled model gives higher CSO volume...

  13. Short period forecasting of catchment-scale precipitation. Part II: a water-balance storm model for short-term rainfall and flood forecasting

    Directory of Open Access Journals (Sweden)

    V. A. Bell

    2000-01-01

    Full Text Available A simple two-dimensional rainfall model, based on advection and conservation of mass in a vertical cloud column, is investigated for use in short-term rainfall and flood forecasting at the catchment scale under UK conditions. The model is capable of assimilating weather radar, satellite infra-red and surface weather observations, together with forecasts from a mesoscale numerical weather prediction model, to obtain frequently updated forecasts of rainfall fields. Such data assimilation helps compensate for the simplified model dynamics and, taken together, provides a practical real-time forecasting scheme for catchment scale applications. Various ways are explored for using information from a numerical weather prediction model (16.8 km grid within the higher resolution model (5 km grid. A number of model variants is considered, ranging from simple persistence and advection methods used as a baseline, to different forms of the dynamic rainfall model. Model performance is assessed using data from the Wardon Hill radar in Dorset for two convective events, on 10 June 1993 and 16 July 1995, when thunderstorms occurred over southern Britain. The results show that (i a simple advection-type forecast may be improved upon by using multiscan radar data in place of data from the lowest scan, and (ii advected, steady-state predictions from the dynamic model, using 'inferred updraughts', provides the best performance overall. Updraught velocity is inferred at the forecast origin from the last two radar fields, using the mass-balance equation and associated data and is held constant over the forecast period. This inference model proves superior to the buoyancy parameterisation of updraught employed in the original formulation. A selection of the different rainfall forecasts is used as input to a catchment flow forecasting model, the IH PDM (Probability Distributed Moisture model, to assess their effect on flow forecast accuracy for the 135 km2 Brue catchment

  14. Comparing flow duration curve and rainfall-runoff modelling for predicting daily runoff in ungauged catchments

    Science.gov (United States)

    Zhang, Yongqiang; Vaze, Jai; Chiew, Francis H. S.; Li, Ming

    2015-06-01

    Predicting daily runoff time series in ungauged catchments is both important and challenging. For the last few decades, the rainfall-runoff (RR) modelling approach has been the method of choice. There have been very few studies reported in literature which attempt to use flow duration curve (FDC) to predict daily runoff time series. This study comprehensively compares the two approaches using an extensive dataset (228 catchments) for a large region of south-eastern Australia and provides guidelines for choosing the suitable method. For each approach we used the nearest neighbour method and two weightings - a 5-donor simple mathematical average (SA) and a 5-donor inverse-distance weighting (5-IDW) - to predict daily runoff time series. The results show that 5-IDW was noticeably better than a single donor to predict daily runoff time series, especially for the FDC approach. The RR modelling approach calibrated against daily runoff outperformed the FDC approach for predicting high flows. The FDC approach was better at predicting medium to low flows in traditional calibration against the Nash-Sutcliffe-Efficiency or Root Mean Square Error, but when calibrated against a low flow objective function, both the FDC and rainfall-runoff models performed equally well in simulating the low flows. These results indicate that both methods can be further improved to simulate daily hydrographs describing the range of flow metrics in ungauged catchments. Further studies should be carried out for improving the accuracy of predicted FDC in ungauged catchments, including improving the FDC model structure and parameter fitting.

  15. Impacts of Noah model physics on catchment-scale runoff simulations

    Science.gov (United States)

    Zheng, Donghai; Van der Velde, Rogier; Su, Zhongbo; Wen, Jun; Wang, Xin; Booij, Martijn J.; Hoekstra, Arjen Y.; Lv, Shihua; Zhang, Yu; Ek, Michael B.

    2016-01-01

    Noah model physics options validated for the source region of the Yellow River (SRYR) are applied to investigate their ability in reproducing runoff at the catchment scale. Three sets of augmentations are implemented affecting descriptions of (i) turbulent and soil heat transport (Noah-H), (ii) soil water flow (Noah-W), and (iii) frozen ground processes (Noah-F). Five numerical experiments are designed with the three augmented versions, a control run with default model physics and a run with all augmentations (Noah-A). Each experiment is set up with vegetation and soil parameters from Weather Research and Forecasting data set, soil organic matter content from China Soil Database, 0.1° atmospheric forcing data from Institute of Tibetan Plateau Research (Chinese Academy of Sciences), and initial equilibrium model states achieved using a single-year recurrent spin-up. In situ heat flux, soil temperature (Ts), and soil moisture (θ) profile measurements are available for point-scale assessment, whereas monthly streamflow is utilized for the catchment-scale evaluation. The comparison with point measurements shows that the augmentations invoked with Noah-H resolve issues with the heat flux and Ts simulation and Noah-W mitigates deficiencies in the θ simulation, while Noah-A yields improvements for both simulated surface energy and water budgets. In contrast, Noah-F has a minor effect. Also, at catchment scale, the best model performance is found for Noah-A leading to a base flow-dominated runoff regime, whereby the surface runoff contribution remains significant. This study highlights the need for a complete description of vertical heat and water exchanges to correctly simulate the runoff in the seasonally frozen and high-altitude SRYR at the catchment scale.

  16. Nitrate reduction in geologically heterogeneous catchments--a framework for assessing the scale of predictive capability of hydrological models.

    Science.gov (United States)

    Refsgaard, Jens Christian; Auken, Esben; Bamberg, Charlotte A; Christensen, Britt S B; Clausen, Thomas; Dalgaard, Esben; Effersø, Flemming; Ernstsen, Vibeke; Gertz, Flemming; Hansen, Anne Lausten; He, Xin; Jacobsen, Brian H; Jensen, Karsten Høgh; Jørgensen, Flemming; Jørgensen, Lisbeth Flindt; Koch, Julian; Nilsson, Bertel; Petersen, Christian; De Schepper, Guillaume; Schamper, Cyril; Sørensen, Kurt I; Therrien, Rene; Thirup, Christian; Viezzoli, Andrea

    2014-01-15

    In order to fulfil the requirements of the EU Water Framework Directive nitrate load from agricultural areas to surface water in Denmark needs to be reduced by about 40%. The regulations imposed until now have been uniform, i.e. the same restrictions for all areas independent of the subsurface conditions. Studies have shown that on a national basis about 2/3 of the nitrate leaching from the root zone is reduced naturally, through denitrification, in the subsurface before reaching the streams. Therefore, it is more cost-effective to identify robust areas, where nitrate leaching through the root zone is reduced in the saturated zone before reaching the streams, and vulnerable areas, where no subsurface reduction takes place, and then only impose regulations/restrictions on the vulnerable areas. Distributed hydrological models can make predictions at grid scale, i.e. at much smaller scale than the entire catchment. However, as distributed models often do not include local scale hydrogeological heterogeneities, they are typically not able to make accurate predictions at scales smaller than they are calibrated. We present a framework for assessing nitrate reduction in the subsurface and for assessing at which spatial scales modelling tools have predictive capabilities. A new instrument has been developed for airborne geophysical measurements, Mini-SkyTEM, dedicated to identifying geological structures and heterogeneities with horizontal and lateral resolutions of 30-50 m and 2m, respectively, in the upper 30 m. The geological heterogeneity and uncertainty are further analysed by use of the geostatistical software TProGS by generating stochastic geological realisations that are soft conditioned against the geophysical data. Finally, the flow paths within the catchment are simulated by use of the MIKE SHE hydrological modelling system for each of the geological models generated by TProGS and the prediction uncertainty is characterised by the variance between the

  17. Land degradation assessment by geo-spatially modeling different soil erodibility equations in a semi-arid catchment.

    Science.gov (United States)

    Saygın, Selen Deviren; Basaran, Mustafa; Ozcan, Ali Ugur; Dolarslan, Melda; Timur, Ozgur Burhan; Yilman, F Ebru; Erpul, Gunay

    2011-09-01

    Land degradation by soil erosion is one of the most serious problems and environmental issues in many ecosystems of arid and semi-arid regions. Especially, the disturbed areas have greater soil detachability and transportability capacity. Evaluation of land degradation in terms of soil erodibility, by using geostatistical modeling, is vital to protect and reclaim susceptible areas. Soil erodibility, described as the ability of soils to resist erosion, can be measured either directly under natural or simulated rainfall conditions, or indirectly estimated by empirical regression models. This study compares three empirical equations used to determine the soil erodibility factor of revised universal soil loss equation prediction technology based on their geospatial performances in the semi-arid catchment of the Saraykoy II Irrigation Dam located in Cankiri, Turkey. A total of 311 geo-referenced soil samples were collected with irregular intervals from the top soil layer (0-10 cm). Geostatistical analysis was performed with the point values of each equation to determine its spatial pattern. Results showed that equations that used soil organic matter in combination with the soil particle size better agreed with the variations in land use and topography of the catchment than the one using only the particle size distribution. It is recommended that the equations which dynamically integrate soil intrinsic properties with land use, topography, and its influences on the local microclimates, could be successfully used to geospatially determine sites highly susceptible to water erosion, and therefore, to select the agricultural and bio-engineering control measures needed.

  18. Development of a New Zealand SedNet model for assessment of catchment-wide soil-conservation works

    Science.gov (United States)

    Dymond, John R.; Herzig, Alexander; Basher, Les; Betts, Harley D.; Marden, Mike; Phillips, Chris J.; Ausseil, Anne-Gaelle E.; Palmer, David J.; Clark, Maree; Roygard, Jon

    2016-03-01

    Much hill country in New Zealand has been converted from indigenous forest to pastoral agriculture, resulting in increased soil erosion. Following a severe storm that hit the Manawatu-Wanaganui region in 2004 and caused 62,000 landslides, the Horizons Regional Council have implemented the Sustainable Land Use Initiative (SLUI), a programme of widespread soil conservation. We have developed a New Zealand version (SedNetNZ) of the Australian SedNet model to evaluate the impact of the SLUI programme in the 5850 km2 Manawatu catchment. SedNetNZ spatially distributes budgets of fine sediment in the landscape. It incorporates landslide, gully, earthflow erosion, surficial erosion, bank erosion, and flood-plain deposition, the important forms of soil erosion in New Zealand. Modelled suspended sediment loads compared well with measured suspended sediment loads with an R2 value of 0.85 after log transformation. A sensitivity analysis gave the uncertainty of estimated suspended sediment loads to be approximately plus or minus 50% (at the 95% confidence level). It is expected that by 2040, suspended sediment loads in targeted water management zones will decrease by about 40%. The expected decrease for the whole catchment is 34%. The expected reduction is due to maturity of tree planting on land at risk to soil erosion. The 34% reduction represents an annual rate of return of 20% on 20 million NZ of investment on soil conservation works through avoided damage to property and infrastructure and avoided clean-up costs.

  19. Modeling approaches to detect land-use changes: Urbanization analyzed on a set of 43 US catchments

    Science.gov (United States)

    Salavati, Bahar; Oudin, Ludovic; Furusho-Percot, Carina; Ribstein, Pierre

    2016-07-01

    Paired catchment approach probably provides the most robust method to detect the effects of land-use change on catchments' flow characteristics. This approach is limited by the availability of two neighbor catchments with and without land-use change under similar climate conditions. This paper uses a hydrological model to detect the hydrological change caused by urbanization. This study describes (1) use a statistical method to evaluate change detection relative to variation of land use change, (2) simulation of non-urban condition for the urban catchment with an alternative approach, to this aim stream flow series of urban catchments have been reconstructed from the period that urbanization had not taken place yet, and (3) the model validation with observed data. This paper intends to compare the flow changes detected by two different approaches: a regional statistical approach (the paired-catchment approach) and a conceptual modeling approach (the residual approach) on the particular case of urbanized catchments. To investigate the sensitivity of the results to the settings of both approaches, the comparison is made on a relatively large number of 43 catchments located in the United States, with relatively large gradients in terms of geomorphology and hydroclimatic characteristics. Results show that the two approaches are generally in relative good agreement in terms of detection and quantification of changes for the three flow characteristics analyzed (mean annual flow, high and low flow characteristics). Besides, it is found that the impact of urbanization on the catchment's hydrologic response is difficult to generalize: the proportion of nonsignificant trends, significantly increasing decreasing trends are on the same order of magnitude, even if an increase in urban areas generally has a greater impact on mean flows and high flows than on low flows.

  20. Ecohydrological modeling of a tropical tidal catchment exposed to anthropogenic pressure

    Science.gov (United States)

    Lorenz, Malte; Zeunert, Stephanie; Meon, Günter

    2016-04-01

    The study area is the highly polluted estuary system of the Thi Vai river and its catchment, located in South Vietnam. It is part of Vietnam's core regions for the development of industrial and agricultural production. The middle and lower parts of the river form an estuary, which is strongly affected by the tide. As a result of untreated industrial waste water discharges, the Thi Vai river was considered as ecological dead from 1990 to 2008. Although the water quality of the Thi Vai has been improved due to waste water treatment and control, it must be still considered as polluted. These first successes could be rapidly negated by the ongoing development of industry, population and agriculture. Today the water quality management is solely focused on the industrial zones adjacent to the estuary. The contribution of the catchment to the water quality pollution is not considered yet. To quantify the pollution of the Thi Vai estuary and its catchment, a monitoring system for water quantity and quality was installed. The water quality of the Thi Vai estuary and its main tributaries is affected by elevated concentrations of NH4, NO2 and TSS and partly reduced DO concentrations. Within the German-Vietnamese BMBF research project EWATEC-COAST a model based management system was developed as an instrument for a sustainable improvement of the water quality of the Thi Vai estuary and the Thi Vai catchment. Among others, the system consists of the hydrodynamic water quality model DELFT 3D and the ecohydrological catchment model PANTA RHEI WQ. The ecohydrological model PANTA RHEI WQ was developed within the research project. The developed ecohydrological model allows a sub-daily time step and includes in-stream water quality procedures, accounting for the interaction of aquatic biomass, dissolved oxygen, nutrients, detritus and sediment. Therefore, the implemented water quality model overcomes deficits found in common ecohydrological models. Despite of the scarce data

  1. Development and application of the distributed hydrologic model based on the two-source PET model and the hybrid runoff model: A case study of Laoha River catchment, Liaohe River Basin%基于双源蒸散和混合产流的分布式水文模型构建及应用——以辽河老哈河流域为例

    Institute of Scientific and Technical Information of China (English)

    刘晓帆; 任立良; 徐静; 袁飞

    2011-01-01

    The Laoha River catchment, Liaohe River Basin in the semi-arid region of northern China is selected for study. The interception evaporation,canopy transpiration and soil evaporation are computed by a physically-based two-source potential evapotranspiration model in each grid cell of the basin. The calculated potential evapotranspiration is regarded as the input of the hybrid runoff model instead of the pan evaporation. Then the grid-basod distributed hydrologic model is built for daily runoff simulation during 1970 - 1979 in the target basin by coupling the two-source PET model in the hybrid runoff model framework. The results show that the two-source PET model can reflect the effects of vegetation type, vegetation physiological features and phonological characteristics on the evapotranspiration. And the grid-based distributed hydrologic model which can illuminate the role of runoff generation and runoff muting is applicable for runoff simulation in the target basin.%以北方半干旱地区的辽河老哈河流域为研究对象,采用网格离散化方法进行水文模拟单元划分,利用具有物理基础的双源蒸散发能力估算模型,计算每个栅格单元的截留蒸发、植被蒸腾能力和土壤蒸发能力,并取代蒸发皿资料作为混合产流模型的蒸散发能力输入,从而构建摹于双源蒸散与混合产流的分布式水文模型,并对老哈河流域1970-1979年的日径流过程进行模拟分析,结果表明双源蒸散发能力计算模型能够考虑植被类型及其生理、物候特性对蒸散发能力的影响.将其与混合产流模型进行嵌套构建的分布式水文模型能较合理地揭示研究区域的产汇流规律,适用于该地区的水文过程模拟.

  2. A Paddock to reef monitoring and modelling framework for the Great Barrier Reef: Paddock and catchment component.

    Science.gov (United States)

    Carroll, Chris; Waters, David; Vardy, Suzanne; Silburn, David M; Attard, Steve; Thorburn, Peter J; Davis, Aaron M; Halpin, Neil; Schmidt, Michael; Wilson, Bruce; Clark, Andrew

    2012-01-01

    Targets for improvements in water quality entering the Great Barrier Reef (GBR) have been set through the Reef Water Quality Protection Plan (Reef Plan). To measure and report on progress towards the targets set a program has been established that combines monitoring and modelling at paddock through to catchment and reef scales; the Paddock to Reef Integrated Monitoring, Modelling and Reporting Program (Paddock to Reef Program). This program aims to provide evidence of links between land management activities, water quality and reef health. Five lines of evidence are used: the effectiveness of management practices to improve water quality; the prevalence of management practice adoption and change in catchment indicators; long-term monitoring of catchment water quality; paddock & catchment modelling to provide a relative assessment of progress towards meeting targets; and finally marine monitoring of GBR water quality and reef ecosystem health. This paper outlines the first four lines of evidence.

  3. Multi-criteria assessment of the Representative Elementary Watershed approach on the Donga catchment (Benin using a downward approach of model complexity

    Directory of Open Access Journals (Sweden)

    N. Varado

    2005-11-01

    Full Text Available This study is part of the AMMA – African Multidisciplinary Monsoon Analysis – project and aims at a better understanding and modelling of the Donga catchment (580 km2, Benin behaviour. For this purpose, we applied the REW concept proposed by Reggiani et al. (1998, 1999, which allows the description of the main local processes at the sub-watershed scale. Such distributed hydrological models, which represent hydrological processes at various scales, should be evaluated not only on the discharge at the outlet but also on each of the represented processes and in several points of the catchment. This kind of multi-criteria evaluation is of importance in order to assess the global behaviour of the models. We applied such multi-criteria strategy to the Donga catchment (586 km2, in Benin. The work is supported by a strategy of observation, undertaken since 1998 consisting in a network of 20 rain gauges, an automatic meteorological station, 6 discharge stations and 18 wells.

    The first goal of this study is to assess the model ability to reproduce the discharge at the outlet, the water table dynamics in several points of the catchment and the vadose zone dynamics at the sub-catchment scale. We tested two spatial discretisations of increasing resolution. To test the internal structure of the model, we looked at its ability to represent also the discharge at intermediary stations. After adjustment of soil parameters, the model is shown to accurately represent discharge down to a drainage area of 100 km2, whereas poorer simulation is achieved on smaller catchments. We introduced the spatial variability of rainfall by distributing the daily rainfall over the REW and obtained a very low sensitivity of the model response to this variability. Our results suggest that processes in the unsaturated zone should first be improved, in order to better simulate soil water dynamics and represent perched water tables which

  4. Water quality improvements from afforestation in an agricultural catchment in Denmark illustrated with the INCA model

    Directory of Open Access Journals (Sweden)

    A. Bastrup-Birk

    2004-01-01

    Full Text Available Intensive agricultural land use across Europe has altered nitrogen (N budget of catchments substantially, causing widespread N pollution of freshwater. Although the N cycle in forests has changed due to increased N deposition, most forest soil waters in Europe have low nitrate concentrations. The protective function of forests on water quality has led to increasing interest in the planting of new forests on arable land as a measure to protect valuable or sensitive freshwater resources. The paper illustrates the effects of afforestation on water and N cycling using the Integrated Nitrogen Catchment (INCA model. The model was calibrated on the Horndrup catchment in the eastern part of Jutland, Denmark, which is dominated by agricultural land use but also covered by 18% of forest land. The dynamics of nitrate concentrations in the stream water were simulated successfully by INCA over a three-year period. The simulation of the dynamics of nitrate concentrations in the soil water is closely linked to the simulation of the hydrological dynamics and especially to the rainfall. The best fit was achieved for both arable and forest land during the wettest year of the study period. The model was then used to simulate the effect of afforestation of a catchment dominated by agriculture on N fluxes with seepage and runoff. Scenarios of whole catchment conversion to forest were run, based on observations of evapotranspiration and N deposition from other Danish sites. The simulated conversion to mature forest reduced runoff by 30–45% and reduced the nitrate concentrations in the soil water by 50–70%. The simulated effect of afforestation on N leaching was an almost direct reflection of the change in the N input: substantial changes in the plant demand and soil N dynamics over the afforestation period were not simulated. To simulate the N dynamics over longer time-scales, appropriate for the study of afforestation, it is suggested that the INCA model be run

  5. Effects of model input data uncertainty in simulating water resources of a transnational catchment

    Science.gov (United States)

    Camargos, Carla; Breuer, Lutz

    2016-04-01

    Landscape consists of different ecosystem components and how these components affect water quantity and quality need to be understood. We start from the assumption that water resources are generated in landscapes and that rural land use (particular agriculture) has a strong impact on water resources that are used downstream for domestic and industrial supply. Partly located in the north of Luxembourg and partly in the southeast of Belgium, the Haute-Sûre catchment is about 943 km2. As part of the catchment, the Haute-Sûre Lake is an important source of drinking water for Luxembourg population, satisfying 30% of the city's demand. The objective of this study is investigate impact of spatial input data uncertainty on water resources simulations for the Haute-Sûre catchment. We apply the SWAT model for the period 2006 to 2012 and use a variety of digital information on soils, elevation and land uses with various spatial resolutions. Several objective functions are being evaluated and we consider resulting parameter uncertainty to quantify an important part of the global uncertainty in model simulations.

  6. Modelling and optimization of land use/land cover change in a developing urban catchment.

    Science.gov (United States)

    Xu, Ping; Gao, Fei; He, Junchao; Ren, Xinxin; Xi, Weijin

    2017-06-01

    The impacts of land use/cover change (LUCC) on hydrological processes and water resources are mainly reflected in changes in runoff and pollutant variations. Low impact development (LID) technology is utilized as an effective strategy to control urban stormwater runoff and pollution in the urban catchment. In this study, the impact of LUCC on runoff and pollutants in an urbanizing catchment of Guang-Ming New District in Shenzhen, China, were quantified using a dynamic rainfall-runoff model with the EPA Storm Water Management Model (SWMM). Based on the simulations and observations, the main objectives of this study were: (1) to evaluate the catchment runoff and pollutant variations with LUCC, (2) to select and optimize the appropriate layout of LID in a planning scenario for reducing the growth of runoff and pollutants under LUCC, (3) to assess the optimal planning schemes for land use/cover. The results showed that compared to 2013, the runoff volume, peak flow and pollution load of suspended solids (SS), and chemical oxygen demand increased by 35.1%, 33.6% and 248.5%, and 54.5% respectively in a traditional planning scenario. The assessment result of optimal planning of land use showed that annual rainfall control of land use for an optimal planning scenario with LID technology was 65%, and SS pollutant load reduction efficiency 65.6%.

  7. PyCatch: Component based hydrological catchment modelling

    NARCIS (Netherlands)

    Lana-Renault, N.; Karssenberg, D.J.

    2013-01-01

    Dynamic numerical models are powerful tools for representing and studying environmental processes through time. Usually they are constructed with environmental modelling languages, which are high-level programming languages that operate at the level of thinking of the scientists. In this paper we pr

  8. UK catchment nutrient loads 1993-2003, a new approach using harmonised monitoring scheme data: temporal changes, geographical distribution, limiting nutrients and loads to coastal waters.

    Science.gov (United States)

    Earl, Timothy J; Upton, Graham J G; Nedwell, David B

    2014-07-01

    The work provides robust estimates of nutrient loads (nitrate and phosphate) from all UK catchments: as required by the Water Framework Directive to monitor catchments' health, and to inform management of these environments. To calculate nutrient loads, data for nutrient concentrations and water flow are combined. In the UK, flow data are typically available at hourly intervals at more than 1300 gauging stations but concentration data are collected less frequently (roughly weekly) and at fewer locations (about 280). The sparseness of the concentration data limits the occasions for which load can be calculated, so a mathematical model was derived which was used to interpolate the concentrations between measurements. The model's parameters provide useful information about the annual nutrient concentration cycles within any catchment, and permitted improved estimates of both the annual loads of N and P, and of the N : P ratios, from mainland UK catchments. Data from 1993-2003 showed nitrate loads from UK catchments were generally constant, while orthophosphate loads generally declined. N : P ratios suggested that most catchments in the north and west of the UK were potentially P-limited although a few were potentially N-limited, while many in central and eastern UK oscillated seasonally between N and P limitation. Knowledge of the nutrient which is potentially limiting to biological productivity is a key factor for management of a catchment's nutrient loads. Calculations of nutrient export loads to coastal regions showed that UK catchments contributed only about 16.5% of total fluvial loads of nitrate to the North Sea, or about 3% of the total N loads when inputs from the Atlantic were included. Orthophosphate loads from the UK catchments into the North Sea were only 1.7% of the total P inputs from rivers and the Atlantic but did not include riverine inputs of P adsorbed to particles.

  9. Organochlorine pesticides (OCPs) in the Indus River catchment area, Pakistan: Status, soil-air exchange and black carbon mediated distribution.

    Science.gov (United States)

    Bajwa, Anam; Ali, Usman; Mahmood, Adeel; Chaudhry, Muhammad Jamshed Iqbal; Syed, Jabir Hussain; Li, Jun; Zhang, Gan; Jones, Kevin C; Malik, Riffat Naseem

    2016-06-01

    Organochlorine pesticides (OCPs) were investigated in passive air and soil samples from the catchment area of the Indus River, Pakistan. ∑15OCPs ranged between 0.68 and 13.47 ng g(-1) in soil and 375.1-1975 pg m-(3) in air. HCHs and DDTs were more prevalent in soil and air compartments. Composition profile indicated that β-HCH and p,p'-DDE were the dominant of all metabolites among HCHs and DDTs respectively. Moreover, fBC and fTOC were assessed and evaluated their potential role in the distribution status of OCPs. The fTOC and fBC ranged between 0.77 and 2.43 and 0.04-0.30% respectively in soil. Regression analysis showed the strong influence of fBC than fTOC on the distribution of OCPs in the Indus River catchment area soil. Equilibrium status was observed for β-HCH, δ-HCH, p,p'-DDD, o,p'-DDT, TC, HCB and Heptachlor with ff ranged between 0.3 and 0.59 while assessing the soil-air exchange of OCPs.

  10. Significance of spatial variability in precipitation for process-oriented modelling: results from two nested catchments using radar and ground station data

    Directory of Open Access Journals (Sweden)

    D. Tetzlaff

    2005-01-01

    Full Text Available The importance of considering the spatial distribution of rainfall for process-oriented hydrological modelling is well-known. However, the application of rainfall radar data to provide such detailed spatial resolution is still under debate. In this study the process-oriented TACD (Tracer Aided Catchment model, Distributed model had been used to investigate the effects of different spatially distributed rainfall input on simulated discharge and runoff components on an event base. TACD is fully distributed (50x50m2 raster cells and was applied on an hourly base. As model input rainfall data from up to 7 ground stations and high resolution rainfall radar data from operational C-band radar were used. For seven rainfall events the discharge simulations were investigated in further detail for the mountainous Brugga catchment (40km2 and the St. Wilhelmer Talbach (15.2km2 sub-basin, which are located in the Southern Black Forest Mountains, south-west Germany. The significance of spatial variable precipitation data was clearly demonstrated. Dependent on event characteristics, localized rain cells were occasionally poorly captured even by a dense ground station network, and this resulted in inadequate model results. For such events, radar data can provide better input data. However, an extensive data adjustment using ground station data is required. For this purpose a method was developed that considers the temporal variability in rainfall intensity in high temporal resolution in combination with the total rainfall amount of both data sets. The use of the distributed catchment model allowed further insights into spatially variable impacts of different rainfall estimates. Impacts for discharge predictions are the largest in areas that are dominated by the production of fast runoff components. The improvements for distributed runoff simulation using high resolution rainfall radar input data are strongly dependent on the investigated scale, the event

  11. Role of spatial variability of rainfall intensity: improve- ment of Eagleson's classical model to explain the rela- tionship between the coefficient of variation of annual maximum discharge and catchment size

    Science.gov (United States)

    Kuzuha, Yasuhisa; Sivapalan, Murugesu; Tomosugi, Kunio; Kishii, Tokuo; Komatsu, Yosuke

    2006-04-01

    Eagleson's classical regional flood frequency model is investigated. Our intention was not to improve the model, but to reveal previously unidentified important and dominant hydrological processes in it. The change of the coefficient of variation (CV) of annual maximum discharge with catchment area can be viewed as representing the spatial variance of floods in a homogeneous region. Several researchers have reported that the CV decreases as the catchment area increases, at least for large areas. On the other hand, Eagleson's classical studies have been known as pioneer efforts that combine the concept of similarity analysis (scaling) with the derived flood frequency approach. As we have shown, the classical model can reproduce the empirical relationship between the mean annual maximum discharge and catchment area, but it cannot reproduce the empirical decreasing CV-catchment area curve. Therefore, we postulate that previously unidentified hydrological processes would be revealed if the classical model were improved to reproduce the decreasing of CV with catchment area. First, we attempted to improve the classical model by introducing a channel network, but this was ineffective. However, the classical model was improved by introducing a two-parameter gamma distribution for rainfall intensity. What is important is not the gamma distribution itself, but those characteristics of spatial variability of rainfall intensity whose CV decreases with increasing catchment area. Introducing the variability of rainfall intensity into the hydrological simulations explains how the CV of rainfall intensity decreases with increasing catchment area. It is difficult to reflect the rainfall-runoff processes in the model while neglecting the characteristics of rainfall intensity from the viewpoint of annual flood discharge variances.

  12. ANN modeling for flood prediction in the upstream Eure's catchment (France)

    Science.gov (United States)

    Kharroubi, Ouissem; masson, Eric; Blanpain, Olivier; Lallahem, Sami

    2013-04-01

    Rainfall-Runoff relationship at basin scale is strongly depending on the catchment complexity including multi-scale interactions. In extreme events cases (i.e. floods and droughts) this relationship is even more complex and differs from average hydrological conditions making extreme runoff prediction very difficult to achieve. However, flood warning, flood prevention and flood mitigation rely on the possibility to predict both flood peak runoff and lag time. This point is crucial for decision making and flood warning to prevent populations and economical stakes to be damaged by extreme hydrological events. Since 2003 in France, a dedicated state service is in charge of producing flood warning from national level (i.e. SCHAPI) to regional level (i.e. SPC). This flood warning service is combining national weather forecast agency (i.e. Meteo France) together with a fully automated realtime hydrological network (i.e. Rainfall-Runoff) in order to produce a flood warning national map online and provide a set of hydro-meteorological data to the SPC in charge of flood prediction from regional to local scale. The SPC is in fact the flood service delivering hydrological prediction at operational level for decision making about flood alert for municipalities and first help services. Our research in collaboration with the SPC SACN (i.e. "Seine Aval et fleuves Côtiers Normands") is focused on the implementation of an Artificial Neural Network model (ANN) for flood prediction in deferent key points of the Eure's catchment and main subcatchment. Our contribution will focus on the ANN model developed for Saint-Luperce gauging station in the upstream part of the Eure's catchment. Prediction of extreme runoff at Saint-Luperce station is of high importance for flood warning in the Eure's catchment because it gives a good indicator on the extreme status and the downstream propagation of a potential flood event. Despite a good runoff monitoring since 27 years Saint Luperce flood

  13. Bounding species distribution models

    Directory of Open Access Journals (Sweden)

    Thomas J. STOHLGREN, Catherine S. JARNEVICH, Wayne E. ESAIAS,Jeffrey T. MORISETTE

    2011-10-01

    Full Text Available Species distribution models are increasing in popularity for mapping suitable habitat for species of management concern. Many investigators now recognize that extrapolations of these models with geographic information systems (GIS might be sensitive to the environmental bounds of the data used in their development, yet there is no recommended best practice for “clamping” model extrapolations. We relied on two commonly used modeling approaches: classification and regression tree (CART and maximum entropy (Maxent models, and we tested a simple alteration of the model extrapolations, bounding extrapolations to the maximum and minimum values of primary environmental predictors, to provide a more realistic map of suitable habitat of hybridized Africanized honey bees in the southwestern United States. Findings suggest that multiple models of bounding, and the most conservative bounding of species distribution models, like those presented here, should probably replace the unbounded or loosely bounded techniques currently used [Current Zoology 57 (5: 642–647, 2011].

  14. Bounding Species Distribution Models

    Science.gov (United States)

    Stohlgren, Thomas J.; Jarnevich, Cahterine S.; Morisette, Jeffrey T.; Esaias, Wayne E.

    2011-01-01

    Species distribution models are increasing in popularity for mapping suitable habitat for species of management concern. Many investigators now recognize that extrapolations of these models with geographic information systems (GIS) might be sensitive to the environmental bounds of the data used in their development, yet there is no recommended best practice for "clamping" model extrapolations. We relied on two commonly used modeling approaches: classification and regression tree (CART) and maximum entropy (Maxent) models, and we tested a simple alteration of the model extrapolations, bounding extrapolations to the maximum and minimum values of primary environmental predictors, to provide a more realistic map of suitable habitat of hybridized Africanized honey bees in the southwestern United States. Findings suggest that multiple models of bounding, and the most conservative bounding of species distribution models, like those presented here, should probably replace the unbounded or loosely bounded techniques currently used [Current Zoology 57 (5): 642-647, 2011].

  15. Modelling catchment-scale shallow landslide occurrence by means of a subsurface flow path connectivity index

    Directory of Open Access Journals (Sweden)

    C. Lanni

    2012-03-01

    Full Text Available Topographic index-based hydrological models have gained wide use to describe the hydrological control on the triggering of rainfall-induced shallow landslides at the catchment scale. A common assumption in these models is that a spatially continuous water table occurs simultaneously at any point across the catchment. However, during a rainfall event isolated patches of subsurface saturation form above an impeding layer and hydrological connectivity of these patches is a necessary condition for lateral flow initiation at a point on the hillslope.

    Here, a new hydrological model is presented, which allows to account for the concept of hydrological connectivity while keeping the simplicity of the topographic index approach. A dynamic topographic index is used to describe the transient lateral flow that is established at a hillslope element when the rainfall amount exceeds a threshold value allowing for (a development of a perched water table above an impeding layer, (b hydrological connectivity between the hillslope element and its own upslope contributing area. A spatially variable soil depth is the main control of hydrological connectivity in the model. The hydrological model is coupled with the infinite slope stability model, and with a scaling model for the rainfall frequency-duration relationship to determine the return period of the critical rainfall needed to cause instability on three catchments located in the Italian Alps. The results show the good ability of our model in predicting observed shallow landslides. The model is finally used to determine local rainfall intensity-duration thresholds that may lead to shallow landslide initiation.

  16. Large Scale Groundwater Flow Model for Ho Chi Minh City and its Catchment Area, Southern Vietnam

    Science.gov (United States)

    Sigrist, M.; Tokunaga, T.; Takizawa, S.

    2005-12-01

    Ho Chi Minh City (HCMC) has become a fast growing city in recent decades and is still growing at a high pace. The water demand for more than 7 million people has increased tremendously, too. Beside surface water, groundwater is used in big amounts to satisfy the need of water. By now, more than 200,000 wells have been developed with very little control. To investigate the sustainability of the water abstraction, a model had been built for the HCMC area and its surrounding. On the catchment scale (around 24,000km2); however, many questions have remained unsolved. In this study, we first gathered and complied geological and hydrogeological information as well as data on groundwater quality to get an idea on regional groundwater flow pattern and problems related to the temporal change of the groundwater situation. Two problems have been depicted by this study. One is the construction of a water reservoir upstream of the Saigon River. This construction has probably changed the water table of the unconfined aquifer, and hence, has significantly changed the properties of soils in some areas. The other problem is the distribution of salty groundwater. Despite the distance of more than 40km from the seashore, groundwater from some wells in and around HCMC shows high concentrations of chloride. Several wells started to produce non-potable water. The chloride concentrations show a complicated and patchy distribution below HCMC, suggesting the possibility of the remnant saltwater at the time of sediment deposition. On the other hand, seawater invades along the streams far beyond HCMC during the dry season and this might be one of the possible sources of salty groundwater by vertical infiltration. A large-scale geological model was constructed and transformed into a hydrogeological model to better understand and quantify the groundwater flow system and the origin of saltwater. Based on the constructed model and numerical calculation, we discuss the influence of reservoir

  17. Inverse Geochemical Reaction Path Modelling and the Impact of Climate Change on Hydrologic Structure in Snowmelt-Dominated Catchments in the Southwestern USA

    Science.gov (United States)

    Driscoll, J. M.; Meixner, T.; Molotch, N. P.; Sickman, J. O.; Williams, M. W.; McIntosh, J. C.; Brooks, P. D.

    2011-12-01

    contrast, during the dry year infiltration and subsequent displacement of stored water that has had longer contact time with minerals and therefore has become more geochemically evolved to produce a greater difference between snowmelt and catchment outlet hydrochemistry. The results for EMD show little distinction between albite weathering for wet and dry years (55.9g and 66.0g, relatively). A hypothesis for this lack of difference in mineral phase changes may be due to less subsurface storage capacity in EMD relative to GL4. The spatial distribution of snowmelt has also been shown to influence the integrated watershed response, and future work includes using the Alpine Hydrochemical Model (AHM) to further investigate catchment response to these spatial data. The AHM will also provide further insight of surface-groundwater interactions through a more integrated model which includes hydrochemical, biological and physical processes to elucidate catchment response to changes in snowmelt dynamics.

  18. A new, catchment-scale model for simulating methyl and total mercury in soils and surface waters

    Science.gov (United States)

    Futter, M. N.; Poste, A. E.; Whitehead, P. G.; Dillon, P. J.

    2012-04-01

    Mercury (Hg) is a potent and persistent neurotoxin. It is subject to long-range atmospheric transport, accumulates in catchment soils, and can pose health risks to humans and animals both at the point of use as well as in remote locations. Elevated concentrations of methyl mercury (MeHg) in fish are related to atmospheric Hg deposition and have resulted in fish consumption advisories in many parts of North America and Fennoscandia. After more than 150 years of elevated Hg deposition in Europe and North America, there remains a large inventory of Hg in the terrestrial catchments of lakes, which continues to be exported to receiving waters despite decreasing atmospheric inputs. While a substantial Hg pool exists in boreal catchment soils, fluxes of Hg from catchments via stream runoff tend to be much lower than atmospheric Hg inputs. Terrestrial catchments receiving similar atmospheric Hg inputs can have markedly different patterns of Hg output in stream water. Considering the importance of catchment processes in determining Hg flux to lakes and subsequent MeHg concentrations in fish, there is a need to characterize Hg cycling and transport in boreal and temperate forest-covered catchments. We present a new, catchment-scale, process-based dynamic model for simulating Hg in soils and surface waters. The Integrated Catchments Model for Mercury (INCA-Hg) simulates transport of gaseous, dissolved and solid Hg and transformations between elemental (Hg0), ionic (Hg(II)) and MeHg in natural and semi-natural landscapes. The mathematical description represents the model as a series of linked, first-order differential equations describing chemical and hydrological processes in catchment soils and waters which control surface water Hg dynamics and subsequent fluxes to lakes and other receiving waters. The model simulates daily time series between one and one hundred years long and can be applied to catchments ranging in size from Canada where we were able to reproduce observed

  19. Catchment Models and Management Tools for diffuse Contaminants (Sediment, Phosphorus and Pesticides): DIFFUSE Project

    Science.gov (United States)

    Mockler, Eva; Reaney, Simeon; Mellander, Per-Erik; Wade, Andrew; Collins, Adrian; Arheimer, Berit; Bruen, Michael

    2017-04-01

    The agricultural sector is the most common suspected source of nutrient pollution in Irish rivers. However, it is also often the most difficult source to characterise due to its predominantly diffuse nature. Particulate phosphorus in surface water and dissolved phosphorus in groundwater are of particular concern in Irish water bodies. Hence the further development of models and indices to assess diffuse sources of contaminants are required for use by the Irish Environmental Protection Agency (EPA) to provide support for river basin planning. Understanding connectivity in the landscape is a vital component of characterising the source-pathway-receptor relationships for water-borne contaminants, and hence is a priority in this research. The DIFFUSE Project will focus on connectivity modelling and incorporation of connectivity into sediment, nutrient and pesticide risk mapping. The Irish approach to understanding and managing natural water bodies has developed substantially in recent years assisted by outputs from multiple research projects, including modelling and analysis tools developed during the Pathways and CatchmentTools projects. These include the Pollution Impact Potential (PIP) maps, which are an example of research output that is used by the EPA to support catchment management. The PIP maps integrate an understanding of the pollution pressures and mobilisation pathways and, using the source-pathways-receptor model, provide a scientific basis for evaluation of mitigation measures. These maps indicate the potential risk posed by nitrate and phosphate from diffuse agricultural sources to surface and groundwater receptors and delineate critical source areas (CSAs) as a means of facilitating the targeting of mitigation measures. Building on this previous research, the DIFFUSE Project will develop revised and new catchment managements tools focused on connectivity, sediment, phosphorus and pesticides. The DIFFUSE project will strive to identify the state

  20. FLOOD MODEL FOR THE BÓDVA CATCHMENT

    Directory of Open Access Journals (Sweden)

    RÓBERT NÉMETH

    2015-06-01

    Full Text Available In term of floods the current area of Hungary has extensively been endangered. Modelling of flood processes – mainly following the hydrological events in the riverbed – has recently been developed. As far as protection dykes provide protection of the inhabited and agricultural areas, the flood models can run with acceptable preciseness. However, when dykes cannot withstand against the increasing load and a dyke burst occurs, fast and efficient protection measures shall be taken in the protected areas. The dynamic 4D Flood model presented in this paper makes possible a fast modelling of dyke burst occurring in the protected side and spreading of water mass, based on real parameters. For this reason the features of protected area shall be recognised, for example topology of creeks, features of agricultural and inhabited areas, parameters of roads, railways, rainwater drainage, buildings, natural conditions (soil parameters, meteorological characteristics, etc.. The results satisfy the comprehensive demands of the Directorate General for Disaster Prevention of Borsod-Abaúj-Zemplén County. In case of dyke burst, the completed Flood Model can run the expected events of the next hour in a few minutes. This time is enough for the specialists to bring operative decisions to protect the inhabitants and avoid material losses.

  1. Spatial distribution of risk factors for Cryptosporidium spp. transport in an Irish catchment.

    Science.gov (United States)

    Samadder, S R; Ziegler, P; Murphy, T M; Holden, N M

    2010-08-01

    Cryptosporidium spp. has become a major public health concern in many parts of the globe, including Ireland, as a result of recent reported waterborne outbreaks of Cryptosporidiosis. Continuous monitoring of Cryptosporidium spp. in water supplies is not feasible, so a risk-forecasting approach is required. This study reports a globally applicable approach for evaluating the spatial variation in relative risk of contaminating surface water by Cryptosporidium spp. based on a risk potential index (RPI) as an indicator of the potential pollution of surface water. The RPI is predicted by readily available data on land use, rainfall, soil type, slope, soil moisture deficit, and distance from water course. A small catchment in County Meath, Ireland, was chosen to illustrate the analysis of the approach. Data for the study area were digitized and rectified using surveyed ground control points to capture each of the RPI factors, field boundaries, and land use. The six parameters were classified and assigned a relative risk score out of 5. A Geographic Information Systems overlay analysis then was used to calculate a cumulative relative risk score for each month of the year. The analysis indicated that April and June experienced a relatively low risk of Cryptosporidium spp. transport compared with other months of the year. June had the least risk, because more than 98% of the catchment was estimated to be of low or moderate risk (RPI ranges = 0 to 2). December had the highest risk of Cryptosporidium spp. transport, because approximately 20% of the catchment area had a moderately high to very high risk (RPI ranges = 2 to 5). The study also made an attempt to reduce the risk of contaminating surface water by alternative land-use practice and relocating the field boundaries. The study demonstrated a semi-quantitative and readily implemented method for using spatial risk assessment for planning land management to reduce the risk of surface water contamination by Cryptosporidium

  2. A case study of regional catchment water quality modelling to identify pollution control requirements.

    Science.gov (United States)

    Crabtree, B; Seward, A J; Thompson, L

    2006-01-01

    There are four ecologically important river catchments that contain candidate Special Areas of Conservation (cSACs) under the Habitats Directive in the Lake District National Park located in the North of England. These are the rivers Ehen, Kent, Derwent and Eden. For each cSAC, there are defined ecological criteria that include water quality targets to protect the designated species. Stretches of the riverine cSACs in each catchment are failing to meet these and other water quality targets. The Environment Agency commissioned a study of each catchment to provide the underpinning scientific knowledge to allow it to deliver its statutory obligations under the Habitats Directive. SIMCAT river water quality models were produced and used to predict the water quality impacts resulting from a number of water quality planning scenarios aimed at achieving full compliance with the Habitats Directive and other national and EEC water quality targets. The results indicated that further controls on effluent discharges will allow the majority of targets to be met but other sources of pollution will also need to be controlled. The outcome of the study also recognised that water quality improvements alone will not necessarily produce the required improvement to the ecological interest features in each cSAC.

  3. A practical demonstration in modelling diclofenac and propranolol river water concentrations using a GIS hydrology model in a rural UK catchment

    Energy Technology Data Exchange (ETDEWEB)

    Johnson, A.C. [Centre for Ecology and Hydrology (CEH) Wallingford, Benson Lane, Wallingford, Oxfordshire OX10 8BB (United Kingdom)]. E-mail: ajo@ceh.ac.uk; Keller, V. [Centre for Ecology and Hydrology (CEH) Wallingford, Benson Lane, Wallingford, Oxfordshire OX10 8BB (United Kingdom); Williams, R.J. [Centre for Ecology and Hydrology (CEH) Wallingford, Benson Lane, Wallingford, Oxfordshire OX10 8BB (United Kingdom); Young, A. [Centre for Ecology and Hydrology (CEH) Wallingford, Benson Lane, Wallingford, Oxfordshire OX10 8BB (United Kingdom)

    2007-03-15

    An existing GIS hydrology water quality model, LF2000-WQX, was applied to predict the concentrations of the pharmaceuticals diclofenac and propranalol in catchments. As a practical exercise the predominantly rural Tamar (UK) catchment was chosen. Consumption, excretion, and fate data were used to estimate the pharmaceutical input load for the model. The predicted concentrations throughout most of the catchment were 1 ng/L or less under low flow (90th percentile) conditions. However, at a few locations, downstream of small sewage treatment plants, concentrations above 25 ng/L were predicted. This exercise shows that it is relatively straightforward to predict the concentrations of new and emerging organic microcontaminants in real catchments using existing GIS hydrology water quality models. Further testing will be required to establish their accuracy. - A GIS hydrology model was used to predict pharmaceutical concentration hot spots in a rural catchment.

  4. Decadal oscillations and extreme value distribution of river peak flows in the Meuse catchment

    Science.gov (United States)

    De Niel, Jan; Willems, Patrick

    2017-04-01

    In flood risk management, flood probabilities are often quantified through Generalized Pareto distributions of river peak flows. One of the main underlying assumptions is that all data points need to originate from one single underlying distribution (i.i.d. assumption). However, this hypothesis, although generally assumed to be correct for variables such as river peak flows, remains somehow questionable: flooding might indeed be caused by different hydrological and/or meteorological conditions. This study confirms these findings from previous research by showing a clear indication of the link between atmospheric conditions and flooding for the Meuse river in The Netherlands: decadal oscillations of river peak flows can (at least partially) be attributed to the occurrence of westerly weather types. The study further proposes a method to take this correlation between atmospheric conditions and river peak flows into account when calibrating an extreme value distribution for river peak flows. Rather than calibrating one single distribution to the data and potentially violating the i.i.d. assumption, weather type depending extreme value distributions are derived and composed. The study shows that, for the Meuse river in The Netherlands, such approach results in a more accurate extreme value distribution, especially with regards to extrapolations. Comparison of the proposed method with a traditional extreme value analysis approach and an alternative model-based approach for the same case study shows strong differences in the peak flow extrapolation. The design-flood for a 1,250 year return period is estimated at 4,800 m3s-1 for the proposed method, compared with 3,450 m3s-1 and 3,900 m3s-1 for the traditional method and a previous study. The methods were validated based on instrumental and documentary flood information of the past 500 years.

  5. The contribution of Distributed Temperature Sensing (DTS) in streams to assess spatial runoff processes in a moraine dominated agricultural catchment

    DEFF Research Database (Denmark)

    Boegh, Eva; Blemmer, Morten; Holmes, Esbern

    using a high spatial resolution (10-30 m) land use map which includes agricultural crops, forest, wetlands and inhabited areas, and spatial variations in soil types, geology and tile drainage were represented. The DTS system measured diurnal variations in water temperature each meter along a stream...... accumulation of water from individual grids within the catchment to the stream was calculated using a Lidar based (1.6 m resolution) digital elevation model. Many locations with observed (DTS-based) discrete lateral inflows were in good agreement with stream locations receiving extra large inflows from...

  6. Conditional flood frequency and catchment state: a simulation approach

    Science.gov (United States)

    Brettschneider, Marco; Bourgin, François; Merz, Bruno; Andreassian, Vazken; Blaquiere, Simon

    2017-04-01

    Catchments have memory and the conditional flood frequency distribution for a time period ahead can be seen as non-stationary: it varies with the catchment state and climatic factors. From a risk management perspective, understanding the link of conditional flood frequency to catchment state is a key to anticipate potential periods of higher flood risk. Here, we adopt a simulation approach to explore the link between flood frequency obtained by continuous rainfall-runoff simulation and the initial state of the catchment. The simulation chain is based on i) a three state rainfall generator applied at the catchment scale, whose parameters are estimated for each month, and ii) the GR4J lumped rainfall-runoff model, whose parameters are calibrated with all available data. For each month, a large number of stochastic realizations of the continuous rainfall generator for the next 12 months are used as inputs for the GR4J model in order to obtain a large number of stochastic realizations for the next 12 months. This process is then repeated for 50 different initial states of the soil moisture reservoir of the GR4J model and for all the catchments. Thus, 50 different conditional flood frequency curves are obtained for the 50 different initial catchment states. We will present an analysis of the link between the catchment states, the period of the year and the strength of the conditioning of the flood frequency compared to the unconditional flood frequency. A large sample of diverse catchments in France will be used.

  7. Modelling the impact of prescribed global warming on water resources of headwater catchments of the Irrawaddy River and their implications for Loktak Lake, northeast India

    Science.gov (United States)

    Singh, C. R.; Thompson, J. R.; French, J. R.; Kingston, D. G.; Mackay, A. W.

    2010-05-01

    Climate change is likely to have major implications for wetland ecosystems, which will include altered water level regimes due to modifications in local and catchment hydrology. However, substantial uncertainty exists in the precise impacts of climate change on wetlands due in part due to uncertainty in GCM projections. This paper explores the impacts of climate change upon river discharge within three sub-catchments of Loktak Lake, an internationally important wetland in northeast India. This is achieved by running pattern-scaled GCM output through distributed hydrological models (developed using MIKE SHE) of each sub-catchment. The impacts of climate change upon water levels within Loktak Lake are subsequently investigated using a water balance model. Two groups of climate change scenarios are investigated. Group 1 uses results from seven different GCMs for an increase in global mean temperature of 2 °C, the purported threshold of "dangerous" climate change, whilst Group 2 is based on results from the HadCM3 GCM for increases in global mean temperature between 1 °C and 6 °C. Results from the Group 1 scenarios show varying responses between the three sub-catchments. The majority of scenario-sub-catchment combinations (13 out of 21) indicate increases in discharge which vary from hydropower barrage that impounds the lake and necessitating the release of water for barrage structural stability. Although elevated water levels may permit enhanced abstraction for irrigation and domestic uses, future increases in hydropower generation are limited by existing infrastructure. The higher water levels are likely to exacerbate existing ecological deterioration within the lake as well as enhancing problems of flooding of lakeside communities.

  8. Prediction of dissolved reactive phosphorus losses from small agricultural catchments: calibration and validation of a parsimonious model

    Directory of Open Access Journals (Sweden)

    C. Hahn

    2013-10-01

    Full Text Available Eutrophication of surface waters due to diffuse phosphorus (P losses continues to be a severe water quality problem worldwide, causing the loss of ecosystem functions of the respective water bodies. Phosphorus in runoff often originates from a small fraction of a catchment only. Targeting mitigation measures to these critical source areas (CSAs is expected to be most efficient and cost-effective, but requires suitable tools. Here we investigated the capability of the parsimonious Rainfall-Runoff-Phosphorus (RRP model to identify CSAs in grassland-dominated catchments based on readily available soil and topographic data. After simultaneous calibration on runoff data from four small hilly catchments on the Swiss Plateau, the model was validated on a different catchment in the same region without further calibration. The RRP model adequately simulated the discharge and dissolved reactive P (DRP export from the validation catchment. Sensitivity analysis showed that the model predictions were robust with respect to the classification of soils into "poorly drained" and "well drained", based on the available soil map. Comparing spatial hydrological model predictions with field data from the validation catchment provided further evidence that the assumptions underlying the model are valid and that the model adequately accounts for the dominant P export processes in the target region. Thus, the parsimonious RRP model is a valuable tool that can be used to determine CSAs. Despite the considerable predictive uncertainty regarding the spatial extent of CSAs, the RRP can provide guidance for the implementation of mitigation measures. The model helps to identify those parts of a catchment where high DRP losses are expected or can be excluded with high confidence. Legacy P was predicted to be the dominant source for DRP losses and thus, in combination with hydrologic active areas, a high risk for water quality.

  9. Application of ANN and fuzzy logic algorithms for streamflow modelling of Savitri catchment

    Indian Academy of Sciences (India)

    Mahesh Kothari; K D Gharde

    2015-07-01

    The streamflow prediction is an essentially important aspect of any watershed modelling. The black box models (soft computing techniques) have proven to be an efficient alternative to physical (traditional) methods for simulating streamflow and sediment yield of the catchments. The present study focusses on development of models using ANN and fuzzy logic (FL) algorithm for predicting the streamflow for catchment of Savitri River Basin. The input vector to these models were daily rainfall, mean daily evaporation, mean daily temperature and lag streamflow used. In the present study, 20 years (1992–2011) rainfall and other hydrological data were considered, of which 13 years (1992–2004) was for training and rest 7 years (2005–2011) for validation of the models. The mode performance was evaluated by R, RMSE, EV, CE, and MAD statistical parameters. It was found that, ANN model performance improved with increasing input vectors. The results with fuzzy logic models predict the streamflow with single input as rainfall better in comparison to multiple input vectors. While comparing both ANN and FL algorithms for prediction of streamflow, ANN model performance is quite superior.

  10. The River Systems in Small Catchments in the Context of the Horton’s and Schumm’s Laws – Implication for Hydrological Modelling. The Case Study of the Polish Carpathians

    Directory of Open Access Journals (Sweden)

    Bryndal Tomasz

    2015-03-01

    Full Text Available In ungauged catchments, flood hydrographs are usually simulated/reconstructed by simple rainfall-runoff and routing models. Horton’s and Schumm’s ratios serve as the input data for many of these models. In this paper, more than 800 Carpathian catchments (up to 35.2 km2 in area were investigated in context of the “Horton’s and Schumm’s laws”. Results reveal that the “law of stream number” and “law of stream areas” are fulfilled in almost all catchments. The mean that values of the bifurcation ratio (RB and the area ratio (RA reach 3.8 and 4.8, respectively, and are thus comparable to values reported in other regions of the world. However, the “law of stream lengths” is not fulfilled in more than half of the catchments, which is not consistent with many theoretical studies reported in the literature. Only 383 (48% catchments fulfill the “law of stream length”, with the mean value of the length ratio (RL=2.3. There was no relationship found between the geological/geomorphological settings that influence river system development and the spatial distribution of catchments where the “law of stream length” was or was not was fulfilled. A similar conclusion was reached for the spatial distribution of the RB, RL, and RA ratios. These results confirmed that the use of Horton’s and Schumm’s ratios for the evaluation of the influence of geological/geomorphological settings on the river system development is limited. Among the lumped hydrological models, those requiring the RB, RL, and RA ratios have been extensively studied over last decades. This study suggests that the application of these models may be limited in small catchment areas; therefore, more attention should be placed on the development of hydrological models where the RB, RL, and RA ratios are not necessary.

  11. Assessment of vulnerability in karst aquifers using a quantitative integrated numerical model: catchment characterization and high resolution monitoring - Application to semi-arid regions- Lebanon.

    Science.gov (United States)

    Doummar, Joanna; Aoun, Michel; Andari, Fouad

    2016-04-01

    Karst aquifers are highly heterogeneous and characterized by a duality of recharge (concentrated; fast versus diffuse; slow) and a duality of flow which directly influences groundwater flow and spring responses. Given this heterogeneity in flow and infiltration, karst aquifers do not always obey standard hydraulic laws. Therefore the assessment of their vulnerability reveals to be challenging. Studies have shown that vulnerability of aquifers is highly governed by recharge to groundwater. On the other hand specific parameters appear to play a major role in the spatial and temporal distribution of infiltration on a karst system, thus greatly influencing the discharge rates observed at a karst spring, and consequently the vulnerability of a spring. This heterogeneity can only be depicted using an integrated numerical model to quantify recharge spatially and assess the spatial and temporal vulnerability of a catchment for contamination. In the framework of a three-year PEER NSF/USAID funded project, the vulnerability of a karst catchment in Lebanon is assessed quantitatively using a numerical approach. The aim of the project is also to refine actual evapotranspiration rates and spatial recharge distribution in a semi arid environment. For this purpose, a monitoring network was installed since July 2014 on two different pilot karst catchment (drained by Qachqouch Spring and Assal Spring) to collect high resolution data to be used in an integrated catchment numerical model with MIKE SHE, DHI including climate, unsaturated zone, and saturated zone. Catchment characterization essential for the model included geological mapping and karst features (e.g., dolines) survey as they contribute to fast flow. Tracer experiments were performed under different flow conditions (snow melt and low flow) to delineate the catchment area, reveal groundwater velocities and response to snowmelt events. An assessment of spring response after precipitation events allowed the estimation of the

  12. Stormwater runoff pollutant loading distributions and their correlation with rainfall and catchment characteristics in a rapidly industrialized city.

    Science.gov (United States)

    Li, Dongya; Wan, Jinquan; Ma, Yongwen; Wang, Yan; Huang, Mingzhi; Chen, Yangmei

    2015-01-01

    Fast urbanization and industrialization in developing countries result in significant stormwater runoff pollution, due to drastic changes in land-use, from rural to urban. A three-year study on the stormwater runoff pollutant loading distributions of industrial, parking lot and mixed commercial and residential catchments was conducted in the Tongsha reservoir watershed of Dongguan city, a typical, rapidly industrialized urban area in China. This study presents the changes in concentration during rainfall events, event mean concentrations (EMCs) and event pollution loads per unit area (EPLs). The first flush criterion, namely the mass first flush ratio (MFFn), was used to identify the first flush effects. The impacts of rainfall and catchment characterization on EMCs and pollutant loads percentage transported by the first 40% of runoff volume (FF40) were evaluated. The results indicated that the pollutant wash-off process of runoff during the rainfall events has significant temporal and spatial variations. The mean rainfall intensity (I), the impervious rate (IMR) and max 5-min intensity (Imax5) are the critical parameters of EMCs, while Imax5, antecedent dry days (ADD) and rainfall depth (RD) are the critical parameters of FF40. Intercepting the first 40% of runoff volume can remove 55% of TSS load, 53% of COD load, 58% of TN load, and 61% of TP load, respectively, according to all the storm events. These results may be helpful in mitigating stormwater runoff pollution for many other urban areas in developing countries.

  13. Stormwater Runoff Pollutant Loading Distributions and Their Correlation with Rainfall and Catchment Characteristics in a Rapidly Industrialized City

    Science.gov (United States)

    Li, Dongya; Wan, Jinquan; Ma, Yongwen; Wang, Yan; Huang, Mingzhi; Chen, Yangmei

    2015-01-01

    Fast urbanization and industrialization in developing countries result in significant stormwater runoff pollution, due to drastic changes in land-use, from rural to urban. A three-year study on the stormwater runoff pollutant loading distributions of industrial, parking lot and mixed commercial and residential catchments was conducted in the Tongsha reservoir watershed of Dongguan city, a typical, rapidly industrialized urban area in China. This study presents the changes in concentration during rainfall events, event mean concentrations (EMCs) and event pollution loads per unit area (EPLs). The first flush criterion, namely the mass first flush ratio (MFFn), was used to identify the first flush effects. The impacts of rainfall and catchment characterization on EMCs and pollutant loads percentage transported by the first 40% of runoff volume (FF40) were evaluated. The results indicated that the pollutant wash-off process of runoff during the rainfall events has significant temporal and spatial variations. The mean rainfall intensity (I), the impervious rate (IMR) and max 5-min intensity (Imax5) are the critical parameters of EMCs, while Imax5, antecedent dry days (ADD) and rainfall depth (RD) are the critical parameters of FF40. Intercepting the first 40% of runoff volume can remove 55% of TSS load, 53% of COD load, 58% of TN load, and 61% of TP load, respectively, according to all the storm events. These results may be helpful in mitigating stormwater runoff pollution for many other urban areas in developing countries. PMID:25774922

  14. Assimilation of freeze-thaw observations into the NASA Catchment land surface model

    Science.gov (United States)

    Farhadi, L.; Reichle, R. H.; Delannoy, G.

    2012-12-01

    The land surface freeze-thaw (F/T) state controls hydrological and carbon cycling and thus affects water and energy exchanges at land surface. In this research an Observing System Simulation Experiment experiment is conducted using synthetically generated measurements of the F/T state for a region in North America (90-110oW longitude, 45-55oN latitude). The synthetic "truth" is generated using the NASA Catchment land surface model forced with surface meteorological fields from the Modern-Era Retrospective Reanalysis for Research and Applications (MERRA). To generate synthetic measurements, the true categorical F/T state is corrupted with a prescribed amount of F/T classification error. The assimilation experiment employs the same Catchment model except that forcing errors (relative to truth) are introduced via the application of meteorological forcing fields from the Global Land Data Assimilation System (GLDAS). A rule-based approach that incorporates model and observational errors is developed and used for assimilating the categorical F/T measurements into the land surface model (F/T analysis). The effect of the F/T analysis on land surface temperature, soil temperature and soil moisture is examined. In a real-world experiment, the synthetic F/T observations are replaced with F/T observations from the Advanced Microwave Scanning Radiometer Enhanced (AMSR-E). The ultimate goal of this project is to provide a framework for the assimilation of SMAP (Soil Moisture Active Passive) F/T observations into the NASA Catchment land surface model.

  15. Distributed simulation of long-term hydrological processes in a medium-sized periurban catchment under changing land use and rainwater management.

    Science.gov (United States)

    Labbas, Mériem; Braud, Isabelle; Branger, Flora; Kralisch, Sven

    2013-04-01

    Growing urbanization and related anthropogenic processes have a high potential to influence hydrological process dynamics. Typical consequences are an increase of surface imperviousness and modifications of water flow paths due to artificial channels and barriers (combined and separated system, sewer overflow device, roads, ditches, etc.). Periurban catchments, at the edge of large cities, are especially affected by fast anthropogenic modifications. They usually consist of a combination of natural areas, rural areas with dispersed settlements and urban areas mostly covered by built zones and spots of natural surfaces. In the context of the European Water Framework Directive (2000) and the Floods Directive (2007), integrated and sustainable solutions are needed to reduce flooding risks and river pollution at the scale of urban conglomerations or whole catchments. Their thorough management requires models able to assess the vulnerability of the territory and to compare the impact of different rainwater management options and planning issues. To address this question, we propose a methodology based on a multi-scale distributed hydrological modelling approach. It aims at quantifying the impact of ongoing urbanization and stormwater management on the long-term hydrological cycle in medium-sized periurban watershed. This method focuses on the understanding and formalization of dominant periurban hydrological processes from small scales (few ha to few km2) to larger scales (few hundred km2). The main objectives are to 1) simulate both urban and rural hydrological processes and 2) test the effects of different long-term land use and water management scenarios. The method relies on several tools and data: a distributed hydrological model adapted to the characteristics of periurban areas, land use and land cover maps from different dates (past, present, future) and information about rainwater management collected from local authorities. For the application of the method, the

  16. Technical Note: A comparison of model and empirical measures of catchment-scale effective energy and mass transfer

    Directory of Open Access Journals (Sweden)

    C. Rasmussen

    2013-09-01

    Full Text Available Recent work suggests that a coupled effective energy and mass transfer (EEMT term, which includes the energy associated with effective precipitation and primary production, may serve as a robust prediction parameter of critical zone structure and function. However, the models used to estimate EEMT have been solely based on long-term climatological data with little validation using direct empirical measures of energy, water, and carbon balances. Here we compare catchment-scale EEMT estimates generated using two distinct approaches: (1 EEMT modeled using the established methodology based on estimates of monthly effective precipitation and net primary production derived from climatological data, and (2 empirical catchment-scale EEMT estimated using data from 86 catchments of the Model Parameter Estimation Experiment (MOPEX and MOD17A3 annual net primary production (NPP product derived from Moderate Resolution Imaging Spectroradiometer (MODIS. Results indicated positive and significant linear correspondence (R2 = 0.75; P −2 yr−1. Modeled EEMT values were consistently greater than empirical measures of EEMT. Empirical catchment estimates of the energy associated with effective precipitation (EPPT were calculated using a mass balance approach that accounts for water losses to quick surface runoff not accounted for in the climatologically modeled EPPT. Similarly, local controls on primary production such as solar radiation and nutrient limitation were not explicitly included in the climatologically based estimates of energy associated with primary production (EBIO, whereas these were captured in the remotely sensed MODIS NPP data. These differences likely explain the greater estimate of modeled EEMT relative to the empirical measures. There was significant positive correlation between catchment aridity and the fraction of EEMT partitioned into EBIO (FBIO, with an increase in FBIO as a fraction of the total as aridity increases and percentage of

  17. Impact of spatial data resolution on simulated catchment water balances and model performance of the multi-scale TOPLATS model

    Science.gov (United States)

    Bormann, H.

    2006-03-01

    This paper analyses the effect of spatial input data resolution on the simulated water balances and flow components using the multi-scale hydrological model TOPLATS. A data set of 25m resolution of the central German Dill catchment (693 km2) is used for investigation. After an aggregation of digital elevation model, soil map and land use classification to 50 m, 75 m, 100 m, 150 m, 200 m, 300 m, 500 m, 1000 m and 2000 m, water balances and water flow components are calculated for the entire Dill catchment as well as for 3 subcatchments without any recalibration. The study shows that model performance measures and simulated water balances almost remain constant for most of the aggregation steps for all investigated catchments. Slight differences in the simulated water balances and statistical quality measures occur for single catchments at the resolution of 50 m to 500 m (e.g. 0-3% for annual stream flow), significant differences at the resolution of 1000 m and 2000 m (e.g. 2-12% for annual stream flow). These differences can be explained by the fact that the statistics of certain input data (land use data in particular as well as soil physical characteristics) changes significantly at these spatial resolutions. The impact of smoothing the relief by aggregation occurs continuously but is barely reflected by the simulation results. To study the effect of aggregation of land use data in detail, in addition to current land use the effect of aggregation on the water balance calculations based on three different land use scenarios is investigated. Land use scenarios were available aiming on economic optimisation of agricultural and forestry practices at different field sizes (0.5 ha, 1.5 ha and 5.0 ha). The changes in water balance terms, induced by aggregation of the land use scenarios, are comparable with respect to catchment water balances compared to the current land use. A correlation analysis between statistics of input data and simulated annual water fluxes only in

  18. Modelling impacts of climate change on water resources in ungauged and data-scarce watersheds. Application to the Siurana catchment (NE Spain).

    Science.gov (United States)

    Candela, Lucila; Tamoh, Karim; Olivares, Gonzalo; Gomez, Manuel

    2012-12-01

    Gaining knowledge on potential climate change impacts on water resources is a complex process which depends on numerical models capable of describing these processes in quantitative terms. Under limited data or ungauged basin conditions, which constrain the modelling approach, a physically based coherent methodological approach is required. The traditional approach to assess flow regime and groundwater recharge impacts, based on coupling general atmosphere-ocean circulation models (GCM) and hydrologic models, has been investigated in the Siurana ungauged catchment (NE Spain). The future A2 (medium-high) and B1 (medium-low) greenhouse gas scenarios and time slices 2013-2037 (2025) and 2038-2062 (2050), developed by the Intergovernmental Panel on Climate Change (IPCC, 2001), have been selected. For scenario simulations, coupled GCM ECHAM5 scenarios, stochastically downscaled outputs and surface-subsurface modelling to simulate changes in water resources were applied to the catchment. Flow regime analysis was assessed by HEC-HMS, a physically based hydrologic model to assess rainfall-runoff in a catchment, while recharge was estimated with VisualBALAN, a distributed model for natural recharge estimation. Simulations show that the projected climate change at the catchment will affect the entire hydrological system with a maximum of 56% reduction of water resources. While subtle changes are observed for the 2025 time slice, the temperature and precipitation forecast for 2050 shows a maximum increase of 2.2 °C and a decreased precipitation volume of 11.3% in relation to historical values. Regarding historical values, runoff output shows a maximum 20% decrease, and 18% decrease of natural recharge with a certain delay in relation to runoff and rainfall data. According to the results, the most important parameters conditioning future water resources are changes in climatic parameters, but they are highly dependent on soil moisture conditions.

  19. Using High-Resolution Data to Test Parameter Sensitivity of the Distributed Hydrological Model HydroGeoSphere

    Directory of Open Access Journals (Sweden)

    Thomas Cornelissen

    2016-05-01

    Full Text Available Parameterization of physically based and distributed hydrological models for mesoscale catchments remains challenging because the commonly available data base is insufficient for calibration. In this paper, we parameterize a mesoscale catchment for the distributed model HydroGeoSphere by transferring evapotranspiration parameters calibrated at a highly-equipped headwater catchment in addition to literature data. Based on this parameterization, the sensitivity of the mesoscale catchment to spatial variability in land use, potential evapotranspiration and precipitation and of the headwater catchment to mesoscale soil and land use data was conducted. Simulations of the mesoscale catchment with transferred parameters reproduced daily discharge dynamics and monthly evapotranspiration of grassland, deciduous and coniferous vegetation in a satisfactory manner. Precipitation was the most sensitive input data with respect to total runoff and peak flow rates, while simulated evapotranspiration components and patterns were most sensitive to spatially distributed land use parameterization. At the headwater catchment, coarse soil data resulted in a change in runoff generating processes based on the interplay between higher wetness prior to a rainfall event, enhanced groundwater level rise and accordingly, lower transpiration rates. Our results indicate that the direct transfer of parameters is a promising method to benefit highly equipped simulations of the headwater catchments.

  20. Calibration of a lumped nitrogen model in a Mediterranean forested catchment named Fuirosos, (Catalonia).

    Science.gov (United States)

    Medici, C.; Butturini, A.; Bernal, S.; Sabater, F.; Martin, M.; Wade, A.; Frances, F.

    2009-04-01

    Following the philosophy of the process-based INCA-N model (Wade et al., 2004), a recently developed hydrological model, LU4 was extended through the inclusion of processes representing the inorganic nitrogen cycle to create a new model of nitrogen dynamics LU4-N capable of application in Mediterranean systems, which share processes from both wet and arid/semiarid environments (Gallart et al., 2002). This new model represents an advance on the INCA-N model for which problems where observed when simulating the hydrology of Mediterranean catchments (Bernal et al., 2004). The LU4-N model integrates hydrological and N processes in catchment and simulates daily discharge and daily NO3-N and NH4-N concentration. The lumped hydrological model LU4 has been already applied to the Fuirosos catchment giving acceptable results (Medici et al., 2008). The model provides a simplified conceptualization of nitrogen cycle in soil and into the shallow perched saturated zone. It uses a zero order reaction kinetic equation to simulate the mineralization process and first order equation to simulate non-biological fixation, nitrification, denitrification, plant uptake and immobilization. The model structure includes a soil moisture threshold for all the considered soil biological processes. The model also includes two first order reaction equations to simulate the adsorption/desorption dynamic in soil. In the shallow perched aquifer, nitrification and denitrification are the only processes allowed to occur. The calibration period for the N-submodel was the same considered for the calibration of the hydrological model LU4 and it covers approximately three hydrological years (from October 1999 to August 2002). The LU4-N model was also tested against observed data recorded at Fuirosos from August 2002 to June 2003. The LU4-N model was able to match the observed daily pattern for the calibration period, while it was unable to match satisfactorily the daily observed ammonium concentration

  1. Development of integrated catchment and water quality model for urban rivers

    Institute of Scientific and Technical Information of China (English)

    薛重华; 尹海龙; 解铭

    2015-01-01

    This paper presents the development of an urban river water quality model which considers the physical-biochemical processes within rivers and the incorporated urban catchment rainfall-runoff process developed with the time–area method. Unlike other models that simulate the hydrological and receiving water quality processes in the rural areas of the watershed scale, the model developed here is typically efficient for simulating the water quality response to nonpoint loadings from urban drainage systems, where the hydrological process is disturbed by artificially pumped discharge in wet-weather periods. This model is employed to assess the river water quality restoration in Nanfei River in Hefei City, China, where the model is calibrated against the measured data (i.e., the COD, the BOD5, the NH3-N, and the DO) in 2010, and the model parameters are suggested. It is shown that the nonpoint pollutants from the urban catchments contribute 34%-47% of the total pollutant inputs (i.e., the COD, the BOD5, and the NH3-N), despite their low flow component of 13.4%. Apart from the improvement of the wastewater treatment plant effluent (i.e., Grade IV of the Surface Water Quality Standard), a nonpoint loading reduction of 27.2%, 25.1%, and 35.3% of the COD, the BOD5, and the NH3-N are anticipated to meet the designated surface water quality standards of Grade V.

  2. Modeling greenhouse gas emissions (CO2, N2O, CH4) from managed arable soils with a fully coupled hydrology-biogeochemical modeling system simulating water and nutrient transport and associated carbon and nitrogen cycling at catchment scale

    Science.gov (United States)

    Klatt, Steffen; Haas, Edwin; Kraus, David; Kiese, Ralf; Butterbach-Bahl, Klaus; Kraft, Philipp; Plesca, Ina; Breuer, Lutz; Zhu, Bo; Zhou, Minghua; Zhang, Wei; Zheng, Xunhua; Wlotzka, Martin; Heuveline, Vincent

    2014-05-01

    The use of mineral nitrogen fertilizer sustains the global food production and therefore the livelihood of human kind. The rise in world population will put pressure on the global agricultural system to increase its productivity leading most likely to an intensification of mineral nitrogen fertilizer use. The fate of excess nitrogen and its distribution within landscapes is manifold. Process knowledge on the site scale has rapidly grown in recent years and models have been developed to simulate carbon and nitrogen cycling in managed ecosystems on the site scale. Despite first regional studies, the carbon and nitrogen cycling on the landscape or catchment scale is not fully understood. In this study we present a newly developed modelling approach by coupling the fully distributed hydrology model CMF (catchment modelling framework) to the process based regional ecosystem model LandscapeDNDC for the investigation of hydrological processes and carbon and nitrogen transport and cycling, with a focus on nutrient displacement and resulting greenhouse gas emissions in a small catchment at the Yanting Agro-ecological Experimental Station of Purple Soil, Sichuan province, China. The catchment hosts cypress forests on the outer regions, arable fields on the sloping croplands cultivated with wheat-maize rotations and paddy rice fields in the lowland. The catchment consists of 300 polygons vertically stratified into 10 soil layers. Ecosystem states (soil water content and nutrients) and fluxes (evapotranspiration) are exchanged between the models at high temporal scales (hourly to daily) forming a 3-dimensional model application. The water flux and nutrients transport in the soil is modelled using a 3D Richards/Darcy approach for subsurface fluxes with a kinematic wave approach for surface water runoff and the evapotranspiration is based on Penman-Monteith. Biogeochemical processes are modelled by LandscapeDNDC, including soil microclimate, plant growth and biomass allocation

  3. A current precipitation index-based model for continuous daily runoff simulation in seasonally snow covered sub-arctic catchments

    Science.gov (United States)

    Akanegbu, Justice O.; Marttila, Hannu; Ronkanen, Anna-Kaisa; Kløve, Bjørn

    2017-02-01

    A new precipitation index-based model, which includes a snow accumulation and melt component, has been developed to simulate hydrology in high latitude catchments. The model couples a point snowmelt model with a current precipitation index (CPI) formulation to simulate continuous daily runoff from catchments with seasonal snow cover. A new runoff conversion factor: CT and Lf, threshold flow factor ThQ and runoff transformation function Maxbas were introduced into the CPI equation, which converts and transforms the routed daily CPI into daily runoff and maintains the daily base flow in the catchment. The model was developed using twelve sub-arctic boreal catchments located above and below the Arctic Circle in northern Finland, representing a region with considerable seasonal snow cover. The results showed that the model can adequately simulate and produce the dynamics of daily runoff from catchments where the underlying physical conditions are not known. An open-access Excel-based model is provided with this paper for daily runoff simulations. The model can be used to estimate runoff in sub-arctic regions where little data is typically available but significant changes in climate are expected, with considerable shifts in the amount and timing of snowmelt and runoff.

  4. Nitrate reduction in geologically heterogeneous catchments — A framework for assessing the scale of predictive capability of hydrological models

    Energy Technology Data Exchange (ETDEWEB)

    Refsgaard, Jens Christian, E-mail: jcr@geus.dk [Geological Survey of Denmark and Greenland (GEUS) (Denmark); Auken, Esben [Department of Earth Sciences, Aarhus University (Denmark); Bamberg, Charlotte A. [City of Aarhus (Denmark); Christensen, Britt S.B. [Geological Survey of Denmark and Greenland (GEUS) (Denmark); Clausen, Thomas [DHI, Hørsholm (Denmark); Dalgaard, Esben [Department of Earth Sciences, Aarhus University (Denmark); Effersø, Flemming [SkyTEM Aps, Beder (Denmark); Ernstsen, Vibeke [Geological Survey of Denmark and Greenland (GEUS) (Denmark); Gertz, Flemming [Knowledge Center for Agriculture, Skejby (Denmark); Hansen, Anne Lausten [Department of Geosciences and Natural Resource Management, University of Copenhagen (Denmark); He, Xin [Geological Survey of Denmark and Greenland (GEUS) (Denmark); Jacobsen, Brian H. [Department of Food and Resource Economics, University of Copenhagen (Denmark); Jensen, Karsten Høgh [Department of Geosciences and Natural Resource Management, University of Copenhagen (Denmark); Jørgensen, Flemming; Jørgensen, Lisbeth Flindt [Geological Survey of Denmark and Greenland (GEUS) (Denmark); Koch, Julian [Department of Geosciences and Natural Resource Management, University of Copenhagen (Denmark); Nilsson, Bertel [Geological Survey of Denmark and Greenland (GEUS) (Denmark); Petersen, Christian [City of Odder (Denmark); De Schepper, Guillaume [Université Laval, Québec (Canada); Schamper, Cyril [Department of Earth Sciences, Aarhus University (Denmark); and others

    2014-01-01

    In order to fulfil the requirements of the EU Water Framework Directive nitrate load from agricultural areas to surface water in Denmark needs to be reduced by about 40%. The regulations imposed until now have been uniform, i.e. the same restrictions for all areas independent of the subsurface conditions. Studies have shown that on a national basis about 2/3 of the nitrate leaching from the root zone is reduced naturally, through denitrification, in the subsurface before reaching the streams. Therefore, it is more cost-effective to identify robust areas, where nitrate leaching through the root zone is reduced in the saturated zone before reaching the streams, and vulnerable areas, where no subsurface reduction takes place, and then only impose regulations/restrictions on the vulnerable areas. Distributed hydrological models can make predictions at grid scale, i.e. at much smaller scale than the entire catchment. However, as distributed models often do not include local scale hydrogeological heterogeneities, they are typically not able to make accurate predictions at scales smaller than they are calibrated. We present a framework for assessing nitrate reduction in the subsurface and for assessing at which spatial scales modelling tools have predictive capabilities. A new instrument has been developed for airborne geophysical measurements, Mini-SkyTEM, dedicated to identifying geological structures and heterogeneities with horizontal and lateral resolutions of 30–50 m and 2 m, respectively, in the upper 30 m. The geological heterogeneity and uncertainty are further analysed by use of the geostatistical software TProGS by generating stochastic geological realisations that are soft conditioned against the geophysical data. Finally, the flow paths within the catchment are simulated by use of the MIKE SHE hydrological modelling system for each of the geological models generated by TProGS and the prediction uncertainty is characterised by the variance between the

  5. Modeller subjectivity and calibration impacts on hydrological model applications: an event-based comparison for a road-adjacent catchment in south-east Norway.

    Science.gov (United States)

    Kalantari, Zahra; Lyon, Steve W; Jansson, Per-Erik; Stolte, Jannes; French, Helen K; Folkeson, Lennart; Sassner, Mona

    2015-01-01

    Identifying a 'best' performing hydrologic model in a practical sense is difficult due to the potential influences of modeller subjectivity on, for example, calibration procedure and parameter selection. This is especially true for model applications at the event scale where the prevailing catchment conditions can have a strong impact on apparent model performance and suitability. In this study, two lumped models (CoupModel and HBV) and two physically-based distributed models (LISEM and MIKE SHE) were applied to a small catchment upstream of a road in south-eastern Norway. All models were calibrated to a single event representing typical winter conditions in the region and then applied to various other winter events to investigate the potential impact of calibration period and methodology on model performance. Peak flow and event-based hydrographs were simulated differently by all models leading to differences in apparent model performance under this application. In this case-study, the lumped models appeared to be better suited for hydrological events that differed from the calibration event (i.e., events when runoff was generated from rain on non-frozen soils rather than from rain and snowmelt on frozen soil) while the more physical-based approaches appeared better suited during snowmelt and frozen soil conditions more consistent with the event-specific calibration. This was due to the combination of variations in subsurface conditions over the eight events considered, the subsequent ability of the models to represent the impact of the conditions (particularly when subsurface conditions varied greatly from the calibration event), and the different approaches adopted to calibrate the models. These results indicate that hydrologic models may not only need to be selected on a case-by-case basis but also have their performance evaluated on an application-by-application basis since how a model is applied can be equally important as inherent model structure.

  6. A modelling approach to assess the hydrological response of small Mediterranean catchments to the variability of soil characteristics in a context of extreme events

    Directory of Open Access Journals (Sweden)

    C. Manus

    2008-09-01

    Full Text Available This paper presents a modeling study aiming at quantifying the possible impact of soil characteristics on the hydrological response of small ungauged catchments in a context of extreme events. The study focuses on the September 2002 event in the Gard region (South-Eastern France, which led to catastrophic flash-floods. The proposed modeling approach is able to take into account rainfall variability and soil profiles variability. Its spatial discretization is determined using Digital Elevation Model (DEM and a soil map. The model computes infiltration, ponding and vertical soil water distribution, as well as river discharge. The model is set up without any calibration and the soil parameter specification is based on an existing soil database. To perform the simulations, radar rainfall estimations are used at a 1 km2 and 5 min resolution. To specify the soil hydraulic properties, two types of pedotransfer function (PTF are compared. It is shown that the PTF including information about soil structure reflects better the spatial variability that can be encountered in the field. The study is focused on four small ungauged catchments of less than 10 km2, which experienced casualties. Simulated specific peak discharges are found to be in agreement with estimations from a post-event in situ investigation. Examining the dynamics of simulated infiltration and saturation degrees, two different behaviors are shown which correspond to different runoff production mechanisms that could be encountered within catchments of less than 10 km2. They produce simulated runoff coefficients that evolve in time and highlight the variability of the infiltration capacity of the various soil types. Therefore, we propose a cartography distinguishing between areas prone to saturation excess and areas prone only to infiltration excess mechanisms. The questions raised by this modeling study will be useful to improve field observations, aiming at

  7. Simulation of Tritium Transport and Groundwater Age in a Variably Saturated 3D Model, Lake Rotorua Catchment, New Zealand

    Science.gov (United States)

    Daughney, C.; Toews, M. W.; Morgenstern, U.; Cornaton, F. J.; Jackson, B. M.

    2013-12-01

    Lake Rotorua is a focus of culture and tourism in New Zealand. The lake's water quality has declined since the 1970s, partly due to nutrient inputs that reach the lake via the groundwater system. Improved land use management within the catchment requires prediction of the spatial variations of groundwater transit time from land surface to the lake, and from this the prediction of current and future nutrient inflows to the lake. This study combines the two main methods currently available for determination of water age: numerical groundwater models and hydrological tracers. A steady-state 3D finite element model was constructed to simulate groundwater flow and transport of tritium and age at the catchment scale (555 km2). The model materials were defined using a 3D geologic model and included ignimbrites, rhyolites, alluvial and lake bottom sediments. The steady-state saturated groundwater flow model was calibrated using observed groundwater levels in boreholes (111 locations) and stream flow measurements from groundwater-fed streams and springs (61 locations). Hydraulic conductivities and Cauchy boundary conditions associated with the streams, springs and lake were parameterized. The transport parameters for the model were calibrated using 191 tritium samples from 105 locations (springs, streams and boreholes), with most locations having two sample dates. The transport model used steady-state flow, but simulated the transient transport and decay of tritium from rainfall recharge between 1945 and 2012. An additional 1D unsaturated sub-model was added to account for tritium decay from the ground surface to the water table. The sub-model is linked on top of the 3D model, and uses the water table depths and material properties from the 3D model. The adjustable calibration parameters for the transport model were porosity and van Genuchten parameters related to the unsaturated sub-models. Calibration of the flow model was achieved using a combination of automated least

  8. [Spatial distribution of soil moisture and salinity and their influence factors in the farmland of Manas River catchment, Northwest China].

    Science.gov (United States)

    Shen, Hao; Abuduwaili, Jilili

    2015-03-01

    Applying methods of statistics and geo-statistics, Manas River catchment was selected as the research area to study the spatial distribution of soil moisture and salinity in the soil profile as. well as their influence factors. The coupling relationship between soil moisture and salinity presented in the spatial distribution was explored as well. The result showed that the soil moisture was overall at a low level (varying from 14.2% to 20.9%), while the salinity was relatively high (about 6.00-9.15 g . kg-1). The soil profile distribution of water and salt contents both showed a trend of bottom accumulation. The variation of soil water moisture was moderate, while that of salt content was strong. Soil salinity and moisture of all layers showed strong spatial autocorrelation, which were mainly affected by structural factors. The horizontal distribution patterns of water and salt contents were irregular, and were constrained by factors like terrain and landforms, etc. Disturbed by human activities, the coupling relation of soil moisture and salinity became much more complex, but their spatial distribution variation was synchronized to some extent.

  9. Spatially distributed rockfall activity inferred from talus deposits and corresponding rockwall areas in the Gradenbach catchment (Schober Mountains, Austria)

    Science.gov (United States)

    Götz, Joachim; Buckel, Johannes; Heckmann, Tobias

    2013-04-01

    The analysis of alpine sediment cascades requires the identification, differentiation and quantification of sediment sources, storages, and transport processes. This study deals with the origin of alpine sediment transfer and relates primary talus deposits to corresponding rockwall source areas within the Gradenbach catchment (Schober Mountains, Austrian Alps). Sediment storage landforms are based on a detailed geomorphological map of the catchment which was generated to analyse the sediment transfer system. Mapping was mainly performed in the field and supplemented by post-mapping analysis using LIDAR data and digital orthophotos. A fundamental part of the mapping procedure was to capture additional landform-based information with respect to morphometry, activity and connectivity. The applied procedure provides a detailed inventory of sediment storage landforms including additional information on surface characteristics, dominant and secondary erosion and deposition processes, process activity and sediment storage coupling. We develop the working hypothesis that the present-day surface area ratio between rockfall talus (area as a proxy for volume, backed by geophysical analysis of selected talus cones) and corresponding rockwall source area is a measure of rockfall activity since deglaciation; large talus cones derived from small rockwall catchments indicate high activity, while low activity can be inferred where rockfall from large rock faces has created only small deposits. The surface area ratio of talus and corresponding rockwalls is analysed using a landform-based and a process-based approach. For the landform-based approach, we designed a GIS procedure which derives the (hydrological) catchment area of the contact lines of talus and rockwall landforms in the geomorphological map. The process-based approach simulates rockfall trajectories from steep (>45°) portions of a DEM generated by a random-walk rockfall model. By back-tracing those trajectories that

  10. Improving catchment scale water quality modelling with continuous high resolution monitoring of metals in runoff

    Science.gov (United States)

    Saari, Markus; Rossi, Pekka; Blomberg von der Geest, Kalle; Mäkinen, Ari; Postila, Heini; Marttila, Hannu

    2017-04-01

    High metal concentrations in natural waters is one of the key environmental and health problems globally. Continuous in-situ analysis of metals from runoff water is technically challenging but essential for the better understanding of processes which lead to pollutant transport. Currently, typical analytical methods for monitoring elements in liquids are off-line laboratory methods such as ICP-OES (Inductively Coupled Plasma Optical Emission Spectroscopy) and ICP-MS (ICP combined with a mass spectrometer). Disadvantage of the both techniques is time consuming sample collection, preparation, and off-line analysis at laboratory conditions. Thus use of these techniques lack possibility for real-time monitoring of element transport. We combined a novel high resolution on-line metal concentration monitoring with catchment scale physical hydrological modelling in Mustijoki river in Southern Finland in order to study dynamics of processes and form a predictive warning system for leaching of metals. A novel on-line measurement technique based on micro plasma emission spectroscopy (MPES) is tested for on-line detection of selected elements (e.g. Na, Mg, Al, K, Ca, Fe, Ni, Cu, Cd and Pb) in runoff waters. The preliminary results indicate that MPES can sufficiently detect and monitor metal concentrations from river water. Water and Soil Assessment Tool (SWAT) catchment scale model was further calibrated with high resolution metal concentration data. We show that by combining high resolution monitoring and catchment scale physical based modelling, further process studies and creation of early warning systems, for example to optimization of drinking water uptake from rivers, can be achieved.

  11. The hydrologic response of urban catchments to distributed green stormwater infrastructure

    Science.gov (United States)

    Obeid, N.; Cai, X.; Schmidt, A.; Werth, C. J.

    2013-12-01

    Proliferation of impervious surfaces in urban watersheds is a serious problem resulting in an increased risk of flooding frequency and magnitude and combined sewer overflows (CSOs). In many urban areas, green roofs are increasingly being built to minimize the impact of increased stormwater runoff, adding more complexity to the urban hydrology. Studies to assess the performance of green roofs at the watershed scale typically lack description of the physical mechanisms underlying flow in green roofs and use statistical analysis of runoff collected at the point scale and scale it up uniformly and linearly in space and time. Such simplifications are not necessarily representative of realistic conditions since green roof performance may be nonlinear. A Hydrus-1D model for an extensive green roof was calibrated and validated using continuous series of high resolution data. The model captures the properties of the engineered soil matrix and inter-event processes (i.e., drying and evapotranspiration). The model was incorporated into a stochastic watershed model, the Illinois Urban Hydrologic Model (IUHM), to assess the impact of green roofs on urban hydrology at different spatial and temporal scales. The model allows us to examine the impact of different sizes, numbers, and distributions of green roofs in the watershed and to test if a threshold exists below which the effect of green roofs at the watershed scale is not statistically significant, given the heterogeneity of hydrology and rainfall. Preliminary results show that green roofs are capable of retaining 18 - 70% of stormwater volume, reducing the peak runoff rate by 70 - 95% and delaying the onset of runoff by up to 3 hours at the site scale, depending on the antecedent soil moisture and type of storm. At the watershed scale, the impact of green roofs on total runoff at the outlet varies and depends on the density of roofs, the type of storm and inter-event period. This research contributes to impact assessment of

  12. Grid-based water quality simulation at catchment scale: Nitrogen model development and evaluation

    Science.gov (United States)

    Yang, Xiaoqiang; Jomaa, Seifeddine; Rode, Michael

    2017-04-01

    Stream water quality has been changed significantly during last few decades due to changes in human impacts. Accurate and flexible water quality models, which can properly reflect the heterogeneity and long term temporal dynamic of catchment functioning, are still needed. To this end, a new grid-based catchment water quality model was developed based on the mesoscale Hydrological Model (mHM) and the HYdrological Prediction of Environment (HYPE) model. The model structure and parameterization scheme were flexibly designed depending on the spatial heterogeneity of study sites and their specific requirements. Based on that, more detailed spatial information can be provided. Moreover, three main improvements on Nitrate sub-model were implemented: i) nitrate transport processes were conducted in physically connected river networks, allowing time-series point-source inputs added in the exact location of sewage treatment plants; ii) additional retention storage of deep groundwater was included for long term nitrate-N simulation; iii) special design for better taking into account crop rotation was implemented. Those new features can extend the model capability and facilitate the understanding of catchment mechanisms and analysis of future scenarios and measures. The newly developed model was fully verified in the Selke catchment (456 km2), central Germany. Long term discharge and water quality data have been collected at three nested gauging stations (1997-2015). The station Meisdorf, above where 72% of area is occupied by forest, represents the discharge and nutrient exports from forest area. Agricultural land dominates the lower part of the catchment (almost 96% of in-between area of the Meisdorf and the outlet station Hausneindorf) with considerable urban areas. Due to the relatively large number of model parameters, sensitivity analysis was firstly conducted. Subsequently, sensitive parameters were calibrated using stepwise and multi-variable approaches, respectively

  13. Distribution and Abundance of Human Specific Bacteroides and Relation to Traditional Indicators in an Urban Tropical Catchment

    Science.gov (United States)

    Nshimyimana, J.; Shanahan, P.; Thompson, J. R.; Ekklesia, E.; Chua Hock Chye, L.

    2012-12-01

    The Singapore government through its Public Utilities Board is interested in opening Kranji Reservoir to recreational use. However, water courses within the Kranji Reservoir catchment contain human fecal indicator bacteria above recreational water quality criteria; their sources and distribution are unknown. The primary goals of this study were to determine the distribution of fecal indicator bacteria in drainages and water bodies in the Kranji reservoir catchment area. Total coliforms, E. coli, and the DNA-based HF marker (targeting a human specific strain of Bacteroides) were quantified in 27 samples collected in January 2009 and 54 samples collected in July 2009. Correlation of HF marker cell equivalents (CE) and E. coli abundance (colony forming units (CFU) or Most Probable Number (MPN)) to different land-use categories revealed potential sources of fecal contamination to the Kranji reservoir. Notably, areas designated as farming/agricultural were associated with the highest levels of E. coli (geometric mean 30,500 CFU/100 ml) and HF marker (1.23±1.13x106 CE/100 ml ± S.D.) while in general lower HF marker and E. coli levels were observed in residential areas, undeveloped areas, and within the Kranji reservoir (i.e. Kranji Reservoir had 2 to 17 MPN/100 ml of E. coli and 103 to 105 HF marker CE/100 ml). A partial survey of potential point sources for fecal contamination within the farming area revealed a wastewater effluent stream with HF marker levels exceeding 107 CE/100ml. As observed in previous studies, total coliforms and E. coli levels were weakly (RBacteroides dorei, an obligate anaerobe that is not expected to grow in aerated surface waters. In contrast, numerous studies have demonstrated that total coliforms, including E. coli, are able to grow well under some tropical conditions, limiting their utility as neutral tracers of fecal contamination in tropical environments. Phylogenetic analysis of cloned HF marker sequences from Kranji reservoir and

  14. Bounding species distribution models

    Institute of Scientific and Technical Information of China (English)

    Thomas J. STOHLGREN; Catherine S. JARNEVICH; Wayne E. ESAIAS; Jeffrey T. MORISETTE

    2011-01-01

    Species distribution models are increasing in popularity for mapping suitable habitat for species of management concern.Many investigators now recognize that extrapolations of these models with geographic information systems (GIS) might be sensitive to the environmental bounds of the data used in their development,yet there is no recommended best practice for “clamping” model extrapolations.We relied on two commonly used modeling approaches:classification and regression tree (CART) and maximum entropy (Maxent) models,and we tested a simple alteration of the model extrapolations,bounding extrapolations to the maximum and minimum values of primary environmental predictors,to provide a more realistic map of suitable habitat of hybridized Africanized honey bees in the southwestern United States.Findings suggest that multiple models of bounding,and the most conservative bounding of species distribution models,like those presented here,should probably replace the unbounded or loosely bounded techniques currently used [Current Zoology 57 (5):642-647,2011].

  15. Simulating CRN derived erosion rates in a transient Andean catchment using the TTLEM model

    Science.gov (United States)

    Campforts, Benjamin; Vanacker, Veerle; Herman, Frédéric; Schwanghart, Wolfgang; Tenrorio Poma, Gustavo; Govers, Gerard

    2017-04-01

    Assessing the impact of mountain building and erosion on the earth surface is key to reconstruct and predict terrestrial landscape evolution. Landscape evolution models (LEMs) are an essential tool in this research effort as they allow to integrate our growing understanding of physical processes governing erosion and transport of mass across the surface. The recent development of several LEMs opens up new areas of research in landscape evolution. Here, we want to seize this opportunity by answering a fundamental research question: does a model designed to simulate landscape evolution over geological timescales allows to simulate spatially varying erosion rates at a millennial timescale? We selected the highly transient Paute catchment in the Southeastern Ecuadorian Andes as a study area. We found that our model (TTLEM) is capable to better explain the spatial patterns of ca. 30 Cosmogenic Radio Nuclide (CRN) derived catchment wide erosion rates in comparison to a classical, statistical approach. Thus, the use of process-based landscape evolution models may not only be of great help to understand long-term landscape evolution but also in understanding spatial and temporal variations in sediment fluxes at the millennial time scale.

  16. Delineating wetland catchments and modeling hydrologic connectivity using lidar data and aerial imagery

    Science.gov (United States)

    Wu, Qiusheng; Lane, Charles R.

    2017-07-01

    In traditional watershed delineation and topographic modeling, surface depressions are generally treated as spurious features and simply removed from a digital elevation model (DEM) to enforce flow continuity of water across the topographic surface to the watershed outlets. In reality, however, many depressions in the DEM are actual wetland landscape features with seasonal to permanent inundation patterning characterized by nested hierarchical structures and dynamic filling-spilling-merging surface-water hydrological processes. Differentiating and appropriately processing such ecohydrologically meaningful features remains a major technical terrain-processing challenge, particularly as high-resolution spatial data are increasingly used to support modeling and geographic analysis needs. The objectives of this study were to delineate hierarchical wetland catchments and model their hydrologic connectivity using high-resolution lidar data and aerial imagery. The graph-theory-based contour tree method was used to delineate the hierarchical wetland catchments and characterize their geometric and topological properties. Potential hydrologic connectivity between wetlands and streams were simulated using the least-cost-path algorithm. The resulting flow network delineated potential flow paths connecting wetland depressions to each other or to the river network on scales finer than those available through the National Hydrography Dataset. The results demonstrated that our proposed framework is promising for improving overland flow simulation and hydrologic connectivity analysis.

  17. Distributed Parameter Modelling Applications

    DEFF Research Database (Denmark)

    2011-01-01

    Here the issue of distributed parameter models is addressed. Spatial variations as well as time are considered important. Several applications for both steady state and dynamic applications are given. These relate to the processing of oil shale, the granulation of industrial fertilizers and the d......Here the issue of distributed parameter models is addressed. Spatial variations as well as time are considered important. Several applications for both steady state and dynamic applications are given. These relate to the processing of oil shale, the granulation of industrial fertilizers...... sands processing. The fertilizer granulation model considers the dynamics of MAP-DAP (mono and diammonium phosphates) production within an industrial granulator, that involves complex crystallisation, chemical reaction and particle growth, captured through population balances. A final example considers...

  18. Erosivity, surface runoff, and soil erosion estimation using GIS-coupled runoff-erosion model in the Mamuaba catchment, Brazil.

    Science.gov (United States)

    Marques da Silva, Richarde; Guimarães Santos, Celso Augusto; Carneiro de Lima Silva, Valeriano; Pereira e Silva, Leonardo

    2013-11-01

    This study evaluates erosivity, surface runoff generation, and soil erosion rates for Mamuaba catchment, sub-catchment of Gramame River basin (Brazil) by using the ArcView Soil and Water Assessment Tool (AvSWAT) model. Calibration and validation of the model was performed on monthly basis, and it could simulate surface runoff and soil erosion to a good level of accuracy. Daily rainfall data between 1969 and 1989 from six rain gauges were used, and the monthly rainfall erosivity of each station was computed for all the studied years. In order to evaluate the calibration and validation of the model, monthly runoff data between January 1978 and April 1982 from one runoff gauge were used as well. The estimated soil loss rates were also realistic when compared to what can be observed in the field and to results from previous studies around of catchment. The long-term average soil loss was estimated at 9.4 t ha(-1) year(-1); most of the area of the catchment (60%) was predicted to suffer from a low- to moderate-erosion risk (catchment, the soil erosion was estimated to exceed > 12 t ha(-1) year(-1). Expectedly, estimated soil loss was significantly correlated with measured rainfall and simulated surface runoff. Based on the estimated soil loss rates, the catchment was divided into four priority categories (low, moderate, high and very high) for conservation intervention. The study demonstrates that the AvSWAT model provides a useful tool for soil erosion assessment from catchments and facilitates the planning for a sustainable land management in northeastern Brazil.

  19. Long-term modelling of nitrogen turnover and critical loads in a forested catchment using the INCA model

    Directory of Open Access Journals (Sweden)

    J.-J. Langusch

    2002-01-01

    Full Text Available Many forest ecosystems in Central Europe have reached the status of N saturation due to chronically high N deposition. In consequence, the NO3 leaching into ground- and surface waters is often substantial. Critical loads have been defined to abate the negative consequences of the NO3 leaching such as soil acidification and nutrient losses. The steady state mass balance method is normally used to calculate critical loads for N deposition in forest ecosystems. However, the steady state mass balance approach is limited because it does not take into account hydrology and the time until the steady state is reached. The aim of this study was to test the suitability of another approach: the dynamic model INCA (Integrated Nitrogen Model for European Catchments. Long-term effects of changing N deposition and critical loads for N were simulated using INCA for the Lehstenbach spruce catchment (Fichtelgebirge, NE Bavaria, Germany under different hydrological conditions. Long-term scenarios of either increasing or decreasing N deposition indicated that, in this catchment, the response of nitrate concentrations in runoff to changing N deposition is buffered by a large groundwater reservoir. The critical load simulated by the INCA model with respect to a nitrate concentration of 0.4 mg N l–1 as threshold value in runoff was 9.7 kg N ha–1yr–1 compared to 10 kg ha–1yr–1 for the steady state model. Under conditions of lower precipitation (520 mm the resulting critical load was 7.7 kg N ha–1yr–1 , suggesting the necessity to account for different hydrological conditions when calculating critical loads. The INCA model seems to be suitable to calculate critical loads for N in forested catchments under varying hydrological conditions e.g. as a consequence of climate change. Keywords: forest ecosystem, N saturation, critical load, modelling, long-term scenario, nitrate leaching, critical loads reduction, INCA

  20. Temporal and Spatial Distribution of Elements in a Small Catchment, and Buffer Function of Wetland in Longgan Lake, China

    Institute of Scientific and Technical Information of China (English)

    WU Yanhong(吴艳宏); WANG Sumin(王苏民); R. W. Barttarbee; ZHU Yuxin(朱育新)

    2004-01-01

    Wetland is the conjunction of lake and terrene where human activities are concentrated. From the viewpoints of material transport and cycling in the terrene-lake system, wetland is the buffer where sand and mud, heavy metals, pollutants and nutrients are tarried. In this paper, we provide a case study based on the temporal and spatial distribution of elements in the Wangling River catchment, a small sub-catchment of Longgan Lake in the middle reaches of the Yangtze River. We have found that wetland can buffer major heavy metals such as Cr, Cu, etc.significantly, but has a little buffer function to some active elements such as Fe and Mn, which are always transported as solutions. Human activities not only influence the distribution of elements, but also weaken the buffer function of wetland. Intensive human activities in the Longgan Lake area in the past 70 years have been recorded in stream, wetland and lake sediments, especially the human activity events such as deforesting and reclaiming on a large scale in 1958 and the 1980' s. Human activities caused the increase of sedimentation rates since the 1950' s, as well as the increase of elements' concentrations. The extensive use of fertilizers and pesticides since the 1960' s have led to the increase of total P concentrations. Increasing SO2 emission accelerate the process of cation exchange in soil, and enhance the leaching of Mn out of soils. Permanent storing of water causes the soil gleyification that also intensifies the leaching of Mn.These are two major reasons for the obvious increase of manganese concentrations in recent 20 years in Longgan Lake. Intensive human activities since the 1950s' have intensified the population in this region and thus destroyed the buffer function of wetland.

  1. Validating a spatially distributed hydrological model with soil morphology data

    Directory of Open Access Journals (Sweden)

    T. Doppler

    2013-10-01

    Full Text Available Spatially distributed hydrological models are popular tools in hydrology and they are claimed to be useful to support management decisions. Despite the high spatial resolution of the computed variables, calibration and validation is often carried out only on discharge time-series at specific locations due to the lack of spatially distributed reference data. Because of this restriction, the predictive power of these models, with regard to predicted spatial patterns, can usually not be judged. An example of spatial predictions in hydrology is the prediction of saturated areas in agricultural catchments. These areas can be important source areas for the transport of agrochemicals to the stream. We set up a spatially distributed model to predict saturated areas in a 1.2 km2 catchment in Switzerland with moderate topography. Around 40% of the catchment area are artificially drained. We measured weather data, discharge and groundwater levels in 11 piezometers for 1.5 yr. For broadening the spatially distributed data sets that can be used for model calibration and validation, we translated soil morphological data available from soil maps into an estimate of the duration of soil saturation in the soil horizons. We used redox-morphology signs for these estimates. This resulted in a data set with high spatial coverage on which the model predictions were validated. In general, these saturation estimates corresponded well to the measured groundwater levels. We worked with a model that would be applicable for management decisions because of its fast calculation speed and rather low data requirements. We simultaneously calibrated the model to the groundwater levels in the piezometers and discharge. The model was able to reproduce the general hydrological behavior of the catchment in terms of discharge and absolute groundwater levels. However, the accuracy of the groundwater level predictions was not high enough to be used for the prediction of saturated areas

  2. Catchment legacies and time lags: a parsimonious watershed model to predict the effects of legacy storage on nitrogen export.

    Directory of Open Access Journals (Sweden)

    Kimberly J Van Meter

    Full Text Available Nutrient legacies in anthropogenic landscapes, accumulated over decades of fertilizer application, lead to time lags between implementation of conservation measures and improvements in water quality. Quantification of such time lags has remained difficult, however, due to an incomplete understanding of controls on nutrient depletion trajectories after changes in land-use or management practices. In this study, we have developed a parsimonious watershed model for quantifying catchment-scale time lags based on both soil nutrient accumulations (biogeochemical legacy and groundwater travel time distributions (hydrologic legacy. The model accurately predicted the time lags observed in an Iowa watershed that had undergone a 41% conversion of area from row crop to native prairie. We explored the time scales of change for stream nutrient concentrations as a function of both natural and anthropogenic controls, from topography to spatial patterns of land-use change. Our results demonstrate that the existence of biogeochemical nutrient legacies increases time lags beyond those due to hydrologic legacy alone. In addition, we show that the maximum concentration reduction benefits vary according to the spatial pattern of intervention, with preferential conversion of land parcels having the shortest catchment-scale travel times providing proportionally greater concentration reductions as well as faster response times. In contrast, a random pattern of conversion results in a 1:1 relationship between percent land conversion and percent concentration reduction, irrespective of denitrification rates within the landscape. Our modeling framework allows for the quantification of tradeoffs between costs associated with implementation of conservation measures and the time needed to see the desired concentration reductions, making it of great value to decision makers regarding optimal implementation of watershed conservation measures.

  3. Catchment legacies and time lags: a parsimonious watershed model to predict the effects of legacy storage on nitrogen export.

    Science.gov (United States)

    Van Meter, Kimberly J; Basu, Nandita B

    2015-01-01

    Nutrient legacies in anthropogenic landscapes, accumulated over decades of fertilizer application, lead to time lags between implementation of conservation measures and improvements in water quality. Quantification of such time lags has remained difficult, however, due to an incomplete understanding of controls on nutrient depletion trajectories after changes in land-use or management practices. In this study, we have developed a parsimonious watershed model for quantifying catchment-scale time lags based on both soil nutrient accumulations (biogeochemical legacy) and groundwater travel time distributions (hydrologic legacy). The model accurately predicted the time lags observed in an Iowa watershed that had undergone a 41% conversion of area from row crop to native prairie. We explored the time scales of change for stream nutrient concentrations as a function of both natural and anthropogenic controls, from topography to spatial patterns of land-use change. Our results demonstrate that the existence of biogeochemical nutrient legacies increases time lags beyond those due to hydrologic legacy alone. In addition, we show that the maximum concentration reduction benefits vary according to the spatial pattern of intervention, with preferential conversion of land parcels having the shortest catchment-scale travel times providing proportionally greater concentration reductions as well as faster response times. In contrast, a random pattern of conversion results in a 1:1 relationship between percent land conversion and percent concentration reduction, irrespective of denitrification rates within the landscape. Our modeling framework allows for the quantification of tradeoffs between costs associated with implementation of conservation measures and the time needed to see the desired concentration reductions, making it of great value to decision makers regarding optimal implementation of watershed conservation measures.

  4. Spatial analysis of rainfall variation using variogram model parameters of X-band radar images in a small mountainous catchment

    Science.gov (United States)

    Guardiola-Albert, Carolina; Díez-Herrero, Andrés; Bodoque, José M.; Bermejo, Marcos; Rivero-Honegger, Carlos; Yagüe, Carlos; Monjo, Robert; Tapiador, Francisco J.

    2016-04-01

    The present study deals the rainfall spatial variability of a small mountainous catchment, which includes the spatial distribution and variability of convective and stratiform events. This work focuses on the precipitation events with hydrological response in Venero-Claro Basin (Avila, Spain). In this basin of 15 square kilometers, flood events of different magnitudes have been often registered. Therefore, any improvement in understanding rainfall characteristics in the area can be of special importance in rainfall estimation and hence to calibrate and validate hydrological models. These enhancements imply more objectivity of risk studies and more predictive and preventive capacity. To separate events by origin it has been used the dimensionless index defined by Monjo (2015), according to the relative temporal distribution of maximum intensities. The main advantages of this method are that it does not require thresholds, so it can be applied for each rain gauge. The geostatistical variogram tool is used to quantify the spatial characteristics of both kinds of events. Hourly rainfall accumulations over the area are computed with observations from one of the 5 existing X-band radar in Spain and 7 rain gauges located in the zone. For each hour the rainfall variogram model has been fitted with the aid of the X-band radar images. Valuable information is extracted from the stratiform and convective ensembles of variogram models. The variogram model parameters are analyzed to determine characteristics of spatial continuity that differentiates stratiform and convective events, and quartiles of sills and ranges in both ensembles are compared.

  5. Pesticide and metabolite fate, release and transport modelling at catchment scale

    Science.gov (United States)

    Gaßmann, Matthias; Olsson, Oliver; Bauer, Melanie

    2010-05-01

    Pesticides are of great concern in hydrological catchments all over the world. On the one hand they are necessary to guarantee stable agricultural production for an increasing population. On the other hand they endanger life of aquatic animals and freshwater resources. However, not only pesticides but also their degradation products, the metabolites, are toxic to the environment, in some cases even more than the parent material. Thus, it is necessary to optimize pesticide application and management of agricultural land (e.g. grass strips, erosion prevention) with respect and according to their behaviour and degradation in hydrological catchments. Modelling provides a sound tool for assessing the impacts of pesticide management changes on pesticide behaviour at the field and in consecutively surface waters. Most of the various models available in literature do not consider metabolism. This study introduces an applicable integrated model assessing the fate and release of a pesticide and one metabolite at the field and in surface waters of a hydrological catchment. For the development of the field release model, the single-equation pesticide release formula by the OECD (2000) was used, which combines sorption and degradation in one equation. The part of the equation calculating the degradation forms the input of a second OECD equation representing the metabolite with its own parameters. A fraction can be specified describing how much of the degradation product is transferred to the specific metabolite. The river network is simulated with a further development of the MOHID River Network model (MRN). The integration of a pesticide type and a metabolite, with their degradation and volatilization processes are the main improvements of the hydrodynamic channel model. Following, the combined model was set up to the Israeli part of the Upper Jordan River basin, especially the Hula valley. According to the local hydrological conditions, a linear storage with a threshold was

  6. Catchment-scale modeling of nitrogen dynamics in a temperate forested watershed, Oregon. An interdisciplinary communication strategy.

    Science.gov (United States)

    Kellie Vache; Lutz Breuer; Julia Jones; Phil Sollins

    2015-01-01

    We present a systems modeling approach to the development of a place-based ecohydrological model. The conceptual model is calibrated to a variety of existing observations, taken in watershed 10 (WS10) at the HJ Andrews Experimental Forest (HJA) in Oregon, USA, a long term ecological research (LTER) site with a long history of catchment-...

  7. The Application and Performance of Two Soil-Vegetation-Atmosphere Modelling Platforms to a Real Hydrologic Catchment

    Science.gov (United States)

    Rihani, Jehan; Dahl Larsen, Morten Andreas; Stisen, Simon; Refsgaard, Jens Christian; Høgh Jensen, Karsten; Simmer, Clemens

    2013-04-01

    Land surface models are important in providing lower boundary fluxes and moisture for atmospheric models. Despite the increase in complexity and detailed representation of vegetation and root zone, LSMs remain for the most part one-dimensional column models which ignore lateral water flow at the land surface and within the top soil layers. In order to include processes effecting soil moisture variations such as shallow groundwater, runoff, overland flow, and subsurface lateral flow, a number of simulation platforms with varying complexity which couple groundwater, land surface, and atmospheric models have emerged. In this study, we compare two different integrated soil-vegetation-atmosphere modelling platforms: the ParFlow-CLM-COSMO model, developed within the Transregional Collaborative Research Centre (TR32), and the HIRHAM-MIKE SHE model, developed within the HOBE Centre for Hydrology and the HYdrological Modelling for Assessing Climate Change Impacts at differeNT Scales (HYACINTS) project. Both modelling platforms contain distributed, physically based, state-of-the-art components. ParFlow-CLM-COSMO consists of the variably saturated groundwater model ParFlow, the Community Land Model (CLM), and the regional climate and weather forecast model COSMO (German Weather Service, DWD). The HIRHAM-MIKE SHE model consists of the HIRHAM regional climate model (Danish Meteorological Institute), the SWET (Shuttleworth and Wallace Evapotranspiration) land-surface model, and the integrated hydrological model MIKE SHE (DHI). There are differences however between the two platforms in the handling of specific processes within the model components as well as differences in the coupling approach used. During the first part of the comparison study, we focus on the coupled subsurface-landsurface components offline from the atmosphere. One of the main differences in the handling of the subsurface component in both models is the inclusion of lateral flow in the unsaturated zone. In

  8. Effects of Uncertainties in Hydrological Modelling. A Case Study of a Mountainous Catchment in Southern Norway

    Science.gov (United States)

    Engeland, Kolbjorn; Steinsland, Ingelin

    2016-04-01

    The aim of this study is to investigate how the inclusion of uncertainties in inputs and observed streamflow influence the parameter estimation, streamflow predictions and model evaluation. In particular we wanted to answer the following research questions: • What is the effect of including a random error in the precipitation and temperature inputs? • What is the effect of decreased information about precipitation by excluding the nearest precipitation station? • What is the effect of the uncertainty in streamflow observations? • What is the effect of reduced information about the true streamflow by using a rating curve where the measurement of the highest and lowest streamflow is excluded when estimating the rating curve? To answer these questions, we designed a set of calibration experiments and evaluation strategies. We used the elevation distributed HBV model operating on daily time steps combined with a Bayesian formulation and the MCMC routine Dream for parameter inference. The uncertainties in inputs was represented by creating ensembles of precipitation and temperature. The precipitation ensemble were created using a meta-gaussian random field approach. The temperature ensembles were created using a 3D Bayesian kriging with random sampling of the temperature laps rate. The streamflow ensembles were generated by a Bayesian multi-segment rating curve model. Precipitation and temperatures were randomly sampled for every day, whereas the streamflow ensembles were generated from rating curve ensembles, and the same rating curve was always used for the whole time series in a calibration or evaluation run. We chose a catchment with a meteorological station measuring precipitation and temperature, and a rating curve of relatively high quality. This allowed us to investigate and further test the effect of having less information on precipitation and streamflow during model calibration, predictions and evaluation. The results showed that including uncertainty

  9. Process Based Prediction of Flow Distribution at Ungauged Himalayan Catchments using Satellite Data

    Science.gov (United States)

    Muller, M. F.; Thompson, S. E.

    2013-12-01

    In-line hydropower (IHP), whereby micro hydropower turbines are integrated in gravity fed rural water supply systems, is a promising yet underutilized infrastructure synergy in rural mountainous areas of developing countries. In Nepal, although institutional and economic considerations are critical, the available local hydropower potential - in particular the flow availability to drive turbines - is the key feasibility criterion. Yet flow projections in remote areas remain a significant challenge largely due to difficult access and data scarcity. We recently showed that satellite data could be successfully adjusted to generate parameters describing the frequency and intensity of daily rainfall. The flow predictions needed for hydropower siting relate primarily to a frequency domain description, specifically the fluw duration curves, which are closely controlled by these rainfall parameters. This project combines bias-corrected satellite rainfall parameters with remotely sensed stationary watershed data to predict the flow duration curves at ungauged Himalayan watersheds. In particular, we compare the performance of several approaches with different levels of process representation, applied to sparsely gauged, snow-fed and topographically complex catchments with highly seasonal rainfall.

  10. Modelling catchment hydrological responses in a Himalayan Lake as a function of changing land use and land cover

    Indian Academy of Sciences (India)

    Bazigha Badar; Shakil A Romshoo; M A Khan

    2013-04-01

    In this paper, we evaluate the impact of changing land use/land cover (LULC) on the hydrological processes in Dal lake catchment of Kashmir Himalayas by integrating remote sensing, simulation modeling and extensive field observations. Over the years, various anthropogenic pressures in the lake catchment have significantly altered the land system, impairing, \\texttit {inter-alia}, sustained biotic communities and water quality of the lake. The primary objective of this paper was to help a better understanding of the LULC change, its driving forces and the overall impact on the hydrological response patterns. Multi-sensor and multi-temporal satellite data for 1992 and 2005 was used for determining the spatio-temporal dynamics of the lake catchment. Geographic Information System (GIS) based simulation model namely Generalized Watershed Loading Function (GWLF) was used to model the hydrological processes under the LULC conditions. We discuss spatio-temporal variations in LULC and identify factors contributing to these variations and analyze the corresponding impacts of the change on the hydrological processes like runoff, erosion and sedimentation. The simulated results on the hydrological responses reveal that depletion of the vegetation cover in the study area and increase in impervious and bare surface cover due to anthropogenic interventions are the primary reasons for the increased runoff, erosion and sediment discharges in the Dal lake catchment. This study concludes that LULC change in the catchment is a major concern that has disrupted the ecological stability and functioning of the Dal lake ecosystem.

  11. Annual nutrients export modelling by analysis of landuse and topographic information: case of a small Mediterranean catchment.

    Science.gov (United States)

    Payraudeau, S; Tournoud, M G; Cernesson, F; Picot, B

    2001-01-01

    The preservation of water bodies from eutrophication implies accurate estimation of phosphorus and nitrogen loads and the control of nutrient production on a catchment scale. In this paper, a simple tool for the modelling of annual nutrient loads is presented. It is implemented in ARC/INFO GIS using Arc Macro Language (AML). The use of a GIS is justified as the spatial characteristics of the catchment area (land use, industrial wastewater location) dictate water quality. The annual nutrient loads are worked out on the catchment scale, using existing GIS routines together with specific routines developed in AML for hydrological and water quality modelling purposes. The catchment area is divided into hydrological subcatchments with relatively homogeneous spatial characteristics. Each subcatchment is linked to a specific nutrient export potential. These nutrient loads, calculated on a subcatchment-by-subcatchment basis, are conveyed to the outlet of the catchment and allow annual nutrient load estimation. A comparison with a water monitoring study is conducted to verify the adequation of modelling results for phosphorus and nitrogen loads.

  12. Rainfall-runoff modeling for storm events in a coastal forest catchment using neural networks

    Institute of Scientific and Technical Information of China (English)

    WANG Yi; HE Bin

    2008-01-01

    The process of transformation of rainfall into runoff over a catchment is very complex and highly nonlinear and exhibits both temporal and spatial variabilities. In this article, a rainfall-runoff model using the artificial neural networks (ANN) is proposed for simulating the runoff in storm events. The study uses the data from a coastal forest catchmentlocated in Seto Inland Sea, Japan. This article studies the accuracy of the short-term rainfall forecast obtained by ANN time-series analysis techniques and using antecedent rainfall depths and stream flow as the input information. The verification results from the proposed model indicate that the approach of ANN rainfall-runoff model presented in this paper shows a reasonable agreement in rainfall-runoff modeling with high accuracy.

  13. Geo-referenced modelling of metal concentrations in river basins at the catchment scale

    Science.gov (United States)

    Hüffmeyer, N.; Berlekamp, J.; Klasmeier, J.

    2009-04-01

    and the site-specific population and surface area (roof, gutter, street) connected to the local sewer system. For emissions from industry and mine drainage quantitative data on average annual loads are collected. WWTP effluent loads additionally consider average removal during wastewater treatment. Runoff from non-point sources such as agricultural areas and unsealed soils is estimated from average wash-off rates per area multiplied with the total area drained into a specified river reach of the river system. Groundwater infiltration is considered in quantities equal to the base flow in the respective river stretch. The model simulates the steady-state concentration distribution in the whole river basin considering transport and removal processes in the river system. The only major removal process for metals in surface water is sedimentation. Simulations have been carried out exemplary for zinc and copper in the German river basins Main (27,292 km2), Ruhr (4,485 km2) and Sieg (2,832 km2). 3. Results and discussion Model estimations of effluent loads for selected WWTPs agreed well with available surveillance data so that the emission module outcome can be assumed as appropriate starting point for surface water modeling. A detailed comparison of simulated surface water concentrations with monitoring data was performed for zinc in the Ruhr river basin. Good agreement between monitoring data and model simulations was achieved at 20 monitoring sites in the Ruhr River and its major tributaries. GREAT-ER was able to simulate zinc concentrations in surface waters based on estimation of loads from several emission sources and via different emission pathways. A wide applicability of the model was corroborated by successful simulations of zinc concentrations in the Main river basin and simulations for copper in both catchments. The functionality of the model allows for running scenarios with different emission assumptions that can be easily compared. Such case studies can be

  14. Comparison of estuarine sediment record with modelled rates of sediment supply from a western European catchment since 1500

    Science.gov (United States)

    Poirier, Clément; Poitevin, Cyril; Chaumillon, Éric

    2016-09-01

    Marine and estuarine sediment records reporting impacts of historical land use changes exist worldwide, but they are rarely supported by direct quantified evidence of changes in denudation rates on the related catchments. Here we implement a spatially-resolved RUSLE soil erosion model on the 10 000 km2 Charente catchment (France), supplied with realistic scenarios of land-cover and climate changes since 1500, and compare the results to a 14C-dated estuarine sediment record. Despite approximations, the model correctly predicts present-day Charente river sediment load. Back-cast modelling suggests that the Charente catchment is an interesting case where the sediment supply did not change despite increase in soil erosion resulting from 18th-century deforestation because it was mitigated by drier climate during the same period. Silt-sand alternations evidenced in the sediment record were correlated with sub-decadal rainfall variability.

  15. Calibration of a distributed hydrology and land surface model using energy flux measurements

    DEFF Research Database (Denmark)

    Larsen, Morten Andreas Dahl; Refsgaard, Jens Christian; Jensen, Karsten H.

    2016-01-01

    In this study we develop and test a calibration approach on a spatially distributed groundwater-surface water catchment model (MIKE SHE) coupled to a land surface model component with particular focus on the water and energy fluxes. The model is calibrated against time series of eddy flux measure...

  16. Integrated simulation of snow and glacier melt in water and energy balance‐based, distributed hydrological modeling framework at Hunza River Basin of Pakistan Karakoram region

    National Research Council Canada - National Science Library

    Shrestha, Maheswor; Koike, Toshio; Hirabayashi, Yukiko; Xue, Yongkang; Wang, Lei; Rasul, Ghulam; Ahmad, Bashir

    2015-01-01

    Energy budget‐based distributed modeling of snow and glacier melt runoff is essential in a hydrologic model to accurately describe hydrologic processes in cold regions and high‐altitude catchments...

  17. ASSESSMENT OF THE ARTIFICIAL NEURAL NETWORKS TO GEOMORPHIC MODELLING OF SEDIMENT YIELD FOR UNGAUGED CATCHMENTS, ALGERIA

    Directory of Open Access Journals (Sweden)

    Khanchoul Kamel

    2014-01-01

    Full Text Available Knowledge of sediment yield and the factors controlling it provides useful information for estimating erosion intensities within river basins. The objective of this study was to build a model from which suspended sediment yield could be estimated from ungauged rivers using computed sediment yield and physical factors. Researchers working on suspended sediment transported by wadis in the Maghreb are usually facing the lack of available data for such river types. Further study of the prediction of sediment transport in these regions and its variability is clearly required. In this work, ANNs were built between sediment yield established from longterm measurement series at gauging stations in Algerian catchments and corresponding basic physiographic parameters such as rainfall, runoff, lithology index, coefficient of torrentiality, and basin area. The proposed Levenberg-Marquardt and Multilayer Perceptron algorithms to train the neural networks of the current research study was based on the feed-forward backpropagation method with combinations of number of neurons in each hidden layer, transfer function, error goal. Additionally, three statistical measurements, namely the root mean square error (RMSE, the coefficient of determination (R², and the efficiency factor (EF have been reported for examining the forecasting accuracy of the developed model. Single plot displays of network outputs with respect to targets for training have provided good performance results and good fitting . Thus, ANNs were a promising method for predicting suspended sediment yield in ungauged Algerian catchments.

  18. Hydrologic modeling of Low Impact Development systems at the urban catchment scale

    Science.gov (United States)

    Palla, Anna; Gnecco, Ilaria

    2015-09-01

    In this paper, the implementation of Low Impact Development systems (LIDs) as source control solutions that contribute to restore the critical components of natural flow regimes, is analyzed at the urban catchment scale. The hydrologic response of a small urban catchment is investigated under different land use conversion scenarios including the installation of green roofs and permeable pavements. The modeling is undertaken using the EPA SWMM; the "do nothing" scenario is calibrated and validated based on field measurements while the LID control modules are calibrated and validated based on laboratory test measurements. The simulations are carried out by using as input the synthetic hyetographs derived for three different return periods (T = 2, 5 and 10 years). Modeling results confirm the effectiveness of LID solutions even for the design storm event (T = 10 years): in particular a minimum land use conversion area, corresponding to the Effective Impervious Area reduction of 5%, is required to obtain noticeable hydrologic benefits. The conversion scenario response is analyzed by using the peak flow reduction, the volume reduction and the hydrograph delay as hydrologic performance indexes. Findings of the present research show that the hydrologic performance linearly increases with increasing the EIA reduction percentages: at 36% EIA reduction (corresponding to the whole conversion of rooftops and parking lot areas), the peak and volume reductions rise till 0.45 and 0.23 respectively while the hydrograph delay increases till 0.19.

  19. Preferential flow in macroporous swelling soil with internal catchment: model development and applications

    Science.gov (United States)

    Greco, Roberto

    2002-12-01

    A new model of infiltration in swelling and shrinking clay soil was developed. The model consisted of two flow domains: soil matrix, with flow modelled by means of Darcy equation, and macropores; the latter was divided in turn into two sub-domains: shrinkage cracks, with aperture dynamically depending on matrix water content, and permanent macropores, independent of matrix saturation. In the shrinkage cracks sub-domain, a kinematic wave equation was derived by considering laminar motion of thin water films, along two parallel nearly vertical walls; in the permanent macropores sub-domain, a kinematic wave equation was assumed, with parameters physically related with macropores shape and dimension. Exchange of water between macropore domains and matrix was introduced in form of sink terms in the macropores mass balance equations, and as source terms in the matrix continuity equation. Infiltration through macropore walls was modelled using a diffusivity function derived from aggregates sorptivity measurements. The internal catchment was included by considering at each layer a fraction of dead end permanent macropores. Water ponding at the bottom of dead end macropores, infiltrated into the corresponding matrix layer. The model was tested against the results of infiltration transients through a large undisturbed swelling and shrinking clay soil column. Outflow rate from column bottom surface was constantly measured, while water content profile was registered at regular time intervals by means of five TDR horizontal probes. In order to quantify model parameters, characterisation of soil matrix was carried out, providing hydraulic conductivity curve, water retention curve, shrinkage characteristic and aggregates diffusivity. All of the other model parameters, thanks to their clear physical meaning, were estimated from direct observation of soil structure, except macropores morphologic parameters, some of which, although measurable, were obtained by calibration due to

  20. Modeling middle and final flush effects of urban runoff pollution in an urbanizing catchment

    Science.gov (United States)

    Qin, Hua-peng; He, Kang-mao; Fu, Guangtao

    2016-03-01

    In current literature, the first flush effect of urban runoff pollution has been studied and reported extensively. However, the effects of middle and final flushes on pollutant flushing were not given much attention. In addition, few previous studies have discussed the suitability of the widely used exponential wash-off model for describing the middle or final flush processes. In this paper, the Shiyan River catchment, a typical rapidly urbanizing catchment in China, is chosen as a study area to analyze the effects of first, middle and final flushes based on monitoring hydrographs and pollutographs. In order to simulate the middle and final flush processes observed in storm events, a new, realistically simple, parsimonious model (named as logistic wash-off model) is developed with the assumption that surface pollutant loads available for wash-off increase with cumulative runoff volume following a logistic curve. The popular exponential wash-off model and the newly developed model are used and compared in simulating the flush processes in storm events. The results indicate that all the three types of pollutant flushing are observed in the experiment; however, the first flush effect is weak, while the middle and final flush effects are substantial. The exponential model has performed well in simulating the first flush process but failed to simulate well the middle and final flush processes. However, the logistic wash-off model has effectively simulated all the three types of pollutant flush, and particularly, it has performed better in simulating the middle and final flush processes than the exponential model.

  1. Distribution and abundance of human-specific Bacteroides and relation to traditional indicators in an urban tropical catchment.

    Science.gov (United States)

    Nshimyimana, J P; Ekklesia, E; Shanahan, P; Chua, L H C; Thompson, J R

    2014-05-01

    The study goals were to determine the relationship between faecal indicator bacteria (FIB), the HF183 marker and land use, and the phylogenetic diversity of HF183 marker sequences in a tropical urban watershed. Total coliforms, Escherichia coli, and HF183 were quantified in 81 samples categorized as undeveloped, residential and horticultural from the Kranji Reservoir and Catchment in Singapore. Quantitative-PCR for HF183 followed by analysis of variance indicated that horticultural areas had significantly higher geometric means for marker levels (4·3 × 10(4) HF183-GE 100 ml(-1)) than nonhorticultural areas (3·07 × 10(3) HF183-GE 100 ml(-1)). E. coli and HF183 were moderately correlated in horticultural areas (R = 0·59, P = 0·0077), but not elsewhere in the catchment. Initial upstream surveys of candidate sources revealed elevated HF183 in a wastewater treatment effluent but not in aquaculture ponds. The HF183 marker was cloned, sequenced and determined by phylogenetic analysis to match the original marker description. We show that quantification of the HF183 marker is a useful tool for mapping the spatial distribution and potential sources of human sewage contamination in tropical environments such as Singapore. A major challenge for assessment of water quality in tropical environments is the natural occurrence and nonconservative behaviour of FIB. The HF183 marker has been employed in temperate environments as an alternative indicator for human sewage contamination. Our study supports the use of the HF183 marker as an indicator for human sewage in Singapore and motivates further work to determine HF183 marker levels that correspond to public health risk in tropical environments. © 2014 The Authors. published by John Wiley & Sons Ltd on behalf of Society for Applied Microbiology.

  2. Multiscale analysis of surface soil moisture dynamics in a mesoscale catchment utilizing an integrated ecohydrological model

    Science.gov (United States)

    Korres, W.; Reichenau, T. G.; Schneider, K.

    2012-12-01

    Soil moisture is one of the fundamental variables in hydrology, meteorology and agriculture, influencing the partitioning of solar energy into latent and sensible heat flux as well as the partitioning of precipitation into runoff and percolation. Numerous studies have shown that in addition to natural factors (rainfall, soil, topography etc.) agricultural management is one of the key drivers for spatio-temporal patterns of soil moisture in agricultural landscapes. Interactions between plant growth, soil hydrology and soil nitrogen transformation processes are modeled by using a dynamically coupled modeling approach. The process-based ecohydrological model components of the integrated decision support system DANUBIA are used to identify the important processes and feedbacks determining soil moisture patterns in agroecosystems. Integrative validation of plant growth and surface soil moisture dynamics serves as a basis for a spatially distributed modeling analysis of surface soil moisture patterns in the northern part of the Rur catchment (1100 sq km), Western Germany. An extensive three year dataset (2007-2009) of surface soil moisture-, plant- (LAI, organ specific biomass and N) and soil- (texture, N, C) measurements was collected. Plant measurements were carried out biweekly for winter wheat, maize, and sugar beet during the growing season. Soil moisture was measured with three FDR soil moisture stations. Meteorological data was measured with an eddy flux station. The results of the model validation showed a very good agreement between the modeled plant parameters (biomass, green LAI) and the measured parameters with values between 0.84 and 0.98 (Willmotts index of agreement). The modeled surface soil moisture (0 - 20 cm) showed also a very favorable agreement with the measurements for winter wheat and sugar beet with an RMSE between 1.68 and 3.45 Vol.-%. For maize, the RMSE was less favorable particularly in the 1.5 months prior to harvest. The modeled soil

  3. Modelling the impact of prescribed global warming on water resources of headwater catchments of the Irrawaddy River and their implications for Loktak Lake, northeast India

    Directory of Open Access Journals (Sweden)

    C. R. Singh

    2010-05-01

    Full Text Available Climate change is likely to have major implications for wetland ecosystems, which will include altered water level regimes due to modifications in local and catchment hydrology. However, substantial uncertainty exists in the precise impacts of climate change on wetlands due in part due to uncertainty in GCM projections. This paper explores the impacts of climate change upon river discharge within three sub-catchments of Loktak Lake, an internationally important wetland in northeast India. This is achieved by running pattern-scaled GCM output through distributed hydrological models (developed using MIKE SHE of each sub-catchment. The impacts of climate change upon water levels within Loktak Lake are subsequently investigated using a water balance model. Two groups of climate change scenarios are investigated. Group 1 uses results from seven different GCMs for an increase in global mean temperature of 2 °C, the purported threshold of "dangerous" climate change, whilst Group 2 is based on results from the HadCM3 GCM for increases in global mean temperature between 1 °C and 6 °C. Results from the Group 1 scenarios show varying responses between the three sub-catchments. The majority of scenario-sub-catchment combinations (13 out of 21 indicate increases in discharge which vary from <1% to 42% although, in some cases, discharge decreases by as much as 20%. Six of the GCMs suggest overall increases in river flow to Loktak Lake (2–27% whilst the other results in a modest (6% decline. In contrast, the Group 2 scenarios lead to an almost linear increase in total river flow to Loktak Lake with increasing temperature (up to 27% for 6 °C, although two sub-catchments experience reductions in mean discharge for the smallest temperature increases. In all but one Group 1 scenario, and all the Group 2 scenarios, Loktak Lake water levels are higher, regularly reaching the top of a downstream hydropower barrage that impounds the lake and necessitating the

  4. Water Yield and Sediment Yield Simulations for Teba Catchment in Spain Using SWRRB Model: Ⅱ.Simulation Results

    Institute of Scientific and Technical Information of China (English)

    2002-01-01

    Simulated results of water yield, sediment yield, surface runoff, subsurface runoff, peak flow, evapotranspiration, etc., in the Teba catchment, Spain, using SWRRB (Simulator for Water Resources in Rural Basins) model are presented and the related problems are discussed. The results showed that water yield and sediment yield could be satisfactorily simulated using SWRRB model The accuracy of the annual water yield simulation in the Teba catchment was up to 83.68%, which implied that this method could be effectively used to predict the annual or inter-annual water yield and to realize the quantification of geographic elements and processes of a river basin.``

  5. Modeling land use change impacts on water resources in a tropical West African catchment (Dano, Burkina Faso)

    Science.gov (United States)

    Yira, Y.; Diekkrüger, B.; Steup, G.; Bossa, A. Y.

    2016-06-01

    This study investigates the impacts of land use change on water resources in the Dano catchment, Burkina Faso, using a physically based hydrological simulation model and land use scenarios. Land use dynamic in the catchment was assessed through the analysis of four land use maps corresponding to the land use status in 1990, 2000, 2007, and 2013. A reclassification procedure levels out differences between the classification schemes of the four maps. The land use maps were used to build five land use scenarios corresponding to different levels of land use change in the catchment. Water balance was simulated by applying the Water flow and balance Simulation Model (WaSiM) using observed discharge, soil moisture, and groundwater level for model calibration and validation. Model statistical quality measures (R2, NSE and KGE) achieved during calibration and validation ranged between 0.6 and 0.9 for total discharge, soil moisture, and groundwater level, indicating a good agreement between observed and simulated variables. After a successful multivariate validation the model was applied to the land use scenarios. The land use assessment exhibited a decrease of savannah at an annual rate of 2% since 1990. Conversely, cropland and urban areas have increased. Since urban areas occupy only 3% of the catchment it can be assumed that savannah was mainly converted to cropland. The conversion rate of savannah was lower than the annual population growth of 3%. A clear increase in total discharge (+17%) and decrease in evapotranspiration (-5%) was observed following land use change in the catchment. A strong relationship was established between savannah degradation, cropland expansion, discharge increase and reduction of evapotranspiration. The increase in total discharge is related to high peak flow, suggesting (i) an increase in water resources that are not available for plant growth and human consumption and (ii) an alteration of flood risk for both the population within and

  6. Impact of uncertainty description on assimilating hydraulic head in the MIKE SHE distributed hydrological model

    DEFF Research Database (Denmark)

    Zhang, Donghua; Madsen, Henrik; Ridler, Marc E.

    2015-01-01

    uncertainty. In most hydrological EnKF applications, an ad hoc model uncertainty is defined with the aim of avoiding a collapse of the filter. The present work provides a systematic assessment of model uncertainty in DA applications based on combinations of forcing, model parameters, and state uncertainties....... This is tested in a case where groundwater hydraulic heads are assimilated into a distributed and integrated catchment-scale model of the Karup catchment in Denmark. A series of synthetic data assimilation experiments are carried out to analyse the impact of different model uncertainty assumptions...

  7. Evaluating the impact of lower resolutions of digital elevation model on rainfall-runoff modeling for ungauged catchments.

    Science.gov (United States)

    Ghumman, Abul Razzaq; Al-Salamah, Ibrahim Saleh; AlSaleem, Saleem Saleh; Haider, Husnain

    2017-02-01

    Geomorphological instantaneous unit hydrograph (GIUH) usually uses geomorphologic parameters of catchment estimated from digital elevation model (DEM) for rainfall-runoff modeling of ungauged watersheds with limited data. Higher resolutions (e.g., 5 or 10 m) of DEM play an important role in the accuracy of rainfall-runoff models; however, such resolutions are expansive to obtain and require much greater efforts and time for preparation of inputs. In this research, a modeling framework is developed to evaluate the impact of lower resolutions (i.e., 30 and 90 m) of DEM on the accuracy of Clark GIUH model. Observed rainfall-runoff data of a 202-km(2) catchment in a semiarid region was used to develop direct runoff hydrographs for nine rainfall events. Geographical information system was used to process both the DEMs. Model accuracy and errors were estimated by comparing the model results with the observed data. The study found (i) high model efficiencies greater than 90% for both the resolutions, and (ii) that the efficiency of Clark GIUH model does not significantly increase by enhancing the resolution of the DEM from 90 to 30 m. Thus, it is feasible to use lower resolutions (i.e., 90 m) of DEM in the estimation of peak runoff in ungauged catchments with relatively less efforts. Through sensitivity analysis (Monte Carlo simulations), the kinematic wave parameter and stream length ratio are found to be the most significant parameters in velocity and peak flow estimations, respectively; thus, they need to be carefully estimated for calculation of direct runoff in ungauged watersheds using Clark GIUH model.

  8. From basalts to badlands : modelling long-term landscape response to lava damming of an upland catchment in western Turkey

    NARCIS (Netherlands)

    Gorp, van W.

    2014-01-01

    Combining field reconstruction and landscape evolution modelling can be useful to investigate the relative role of different drivers (tectonics, climate, local base level) on long term catchment evolution. In this thesis, field reconstruction and landscape evolution modelling are combined to unravel

  9. Assimilation of Freeze - Thaw Observations into the NASA Catchment Land Surface Model

    Science.gov (United States)

    Farhadi, Leila; Reichle, Rolf H.; DeLannoy, Gabrielle J. M.; Kimball, John S.

    2014-01-01

    The land surface freeze-thaw (F-T) state plays a key role in the hydrological and carbon cycles and thus affects water and energy exchanges and vegetation productivity at the land surface. In this study, we developed an F-T assimilation algorithm for the NASA Goddard Earth Observing System, version 5 (GEOS-5) modeling and assimilation framework. The algorithm includes a newly developed observation operator that diagnoses the landscape F-T state in the GEOS-5 Catchment land surface model. The F-T analysis is a rule-based approach that adjusts Catchment model state variables in response to binary F-T observations, while also considering forecast and observation errors. A regional observing system simulation experiment was conducted using synthetically generated F-T observations. The assimilation of perfect (error-free) F-T observations reduced the root-mean-square errors (RMSE) of surface temperature and soil temperature by 0.206 C and 0.061 C, respectively, when compared to model estimates (equivalent to a relative RMSE reduction of 6.7 percent and 3.1 percent, respectively). For a maximum classification error (CEmax) of 10 percent in the synthetic F-T observations, the F-T assimilation reduced the RMSE of surface temperature and soil temperature by 0.178 C and 0.036 C, respectively. For CEmax=20 percent, the F-T assimilation still reduces the RMSE of model surface temperature estimates by 0.149 C but yields no improvement over the model soil temperature estimates. The F-T assimilation scheme is being developed to exploit planned operational F-T products from the NASA Soil Moisture Active Passive (SMAP) mission.

  10. Effect of the spatiotemporal variability of rainfall inputs in water quality integrated catchment modelling for dissolved oxygen concentrations

    Science.gov (United States)

    Moreno Ródenas, Antonio Manuel; Cecinati, Francesca; ten Veldhuis, Marie-Claire; Langeveld, Jeroen; Clemens, Francois

    2016-04-01

    Maintaining water quality standards in highly urbanised hydrological catchments is a worldwide challenge. Water management authorities struggle to cope with changing climate and an increase in pollution pressures. Water quality modelling has been used as a decision support tool for investment and regulatory developments. This approach led to the development of integrated catchment models (ICM), which account for the link between the urban/rural hydrology and the in-river pollutant dynamics. In the modelled system, rainfall triggers the drainage systems of urban areas scattered along a river. When flow exceeds the sewer infrastructure capacity, untreated wastewater enters the natural system by combined sewer overflows. This results in a degradation of the river water quality, depending on the magnitude of the emission and river conditions. Thus, being capable of representing these dynamics in the modelling process is key for a correct assessment of the water quality. In many urbanised hydrological systems the distances between draining sewer infrastructures go beyond the de-correlation length of rainfall processes, especially, for convective summer storms. Hence, spatial and temporal scales of selected rainfall inputs are expected to affect water quality dynamics. The objective of this work is to evaluate how the use of rainfall data from different sources and with different space-time characteristics affects modelled output concentrations of dissolved oxygen in a simplified ICM. The study area is located at the Dommel, a relatively small and sensitive river flowing through the city of Eindhoven (The Netherlands). This river stretch receives the discharge of the 750,000 p.e. WWTP of Eindhoven and from over 200 combined sewer overflows scattered along its length. A pseudo-distributed water quality model has been developed in WEST (mikedhi.com); this is a lumped-physically based model that accounts for urban drainage processes, WWTP and river dynamics for several

  11. A modeling approach to assess the hydrological response of small mediterranean catchments to the variability of soil characteristics in a context of extreme events

    Directory of Open Access Journals (Sweden)

    C. Manus

    2009-02-01

    Full Text Available This paper presents a modeling study aiming at quantifying the possible impact of soil characteristics on the hydrological response of small ungauged catchments in a context of extreme events. The study focuses on the September 2002 event in the Gard region (South-Eastern France, which led to catastrophic flash-floods. The proposed modeling approach is able to take into account rainfall variability and soil profiles variability. Its spatial discretization is determined using Digital Elevation Model (DEM and a soil map. The model computes infiltration, ponding and vertical soil water distribution, as well as river discharge. In order to be applicable to ungauged catchments, the model is set up without any calibration and the soil parameter specification is based on an existing soil database. The model verification is based on a regional evaluation using 17 estimated discharges obtained from an extensive post-flood investigation. Thus, this approach provides a spatial view of the hydrological response across a large range of scales. To perform the simulations, radar rainfall estimations are used at a 1 km2 and 5 min resolution. To specify the soil hydraulic properties, two types of pedotransfer function (PTF are compared. It is shown that the PTF including information about soil structure reflects better the spatial variability that can be encountered in the field. The study is focused on four small ungauged catchments of less than 10 km2, which experienced casualties. Simulated specific peak discharges are found to be in agreement with estimations from a post-event in situ investigation. Examining the dynamics of simulated infiltration and saturation degrees, two different behaviors are shown which correspond to different runoff production mechanisms that could be encountered within catchments of less than 10 km2. They produce simulated runoff coefficients that evolve in time and highlight the variability of the

  12. Case Study: Effect of Climatic Characterization on River Discharge in an Alpine-Prealpine Catchment of the Spanish Pyrenees Using the SWAT Model

    Directory of Open Access Journals (Sweden)

    Leticia Palazón

    2016-10-01

    Full Text Available The new challenges in assessment of water resources demand new approaches and tools, such as the use of hydrologic models, which could serve to assist managers in the prediction, planning and management of catchment water supplies in view of increased demand of water for irrigation and climatic change. Good characterization of the spatial patterns of climate variables is of paramount importance in hydrological modelling. This is especially so when modelling mountain environments which are characterized by strong altitudinal climate gradients. However, very often there is a poor distribution of climatic stations in these areas, which in many cases, results in under representation of high altitude areas with respect to climatic data. This results in the poor performance of the models. In the present study, the Soil and Water Assessment Tool (SWAT model was applied to the Barasona reservoir catchment in the Central Spanish Pyrenees in order to assess the influence of different climatic characterizations in the monthly river discharges. Four simulations with different input data were assessed, using only the available climate data (A1; the former plus one synthetic dataset at a higher altitude (B1; and both plus the altitudinal climate gradient (A2 and B2. The model’s performance was evaluated against the river discharges for the representative periods of 2003–2005 and 1994–1996 by means of commonly used statistical measures. The best results were obtained using the altitudinal climate gradient alone (scenario A2. This study provided insight into the importance of taking into account the sources and the spatial distribution of weather data in modelling water resources in mountainous catchments.

  13. Investigating the role of geology in the hydrological response of Mediterranean catchments prone to flash-floods: Regional modelling study and process understanding

    Science.gov (United States)

    Vannier, Olivier; Anquetin, Sandrine; Braud, Isabelle

    2016-10-01

    In this study, a regional distributed hydrological model is used to perform long-term and flash-flood event simulations, over the Cévennes-Vivarais region (south of France). The objective is to improve our understanding on the role played by geology on the hydrological processes of catchments during two past flash-flood events. This modelling work is based on Vannier et al. ("Regional estimation of catchment-scale soil properties by means of streamflow recession analysis for use in distributed hydrological models", Hydrological Processes, 2014), where streamflow recessions are analysed to estimate the thickness and hydraulic conductivity of weathered rock layers, depending on the geological nature of catchments. Weathered rock layers are thus implemented into the hydrological model CVN-p, and the contribution of these layers is assessed during flash-flood events simulations as well as during inter-event periods. The model is used without any calibration, to test hypotheses on the active hydrological processes. The results point out two different hydrological behaviours, depending on the geology: on crystalline rocks (granite and gneiss), the addition of a weathered rock layer considerably improves the simulated discharges, during flash-flood events as well as during recession periods, and makes the model able to remarkably reproduce the observed streamflow dynamics. For other geologies (schists especially), the benefits are real, but not sufficient to properly simulate the observed streamflow dynamics. These results probably underline the existence of poorly known processes (flow paths, non-linear spilling process) associated with the planar structure of schisty rocks. On a methodological point of view, this study proposes a simple way to account for the additional storage associated with each geological entity, through the addition of a weathered porous rock layer situated below the traditionally-considered upper soil horizons, and shows its applicability and

  14. Diagnostic analysis of water balance variability: A comparative modeling study of catchments in Perth, Newcastle, and Darwin, Australia

    Science.gov (United States)

    Samuel, Jos M.; Sivapalan, Murugesu; Struthers, Iain

    2008-06-01

    A comparative study is performed to explore interactions between climate variability and landscape factors that control water balance variability in three diverse regions of Australia: Perth (temperate with distinct dry summers); Newcastle (temperate with no distinct dry season); and Darwin (tropical region affected by monsoons). This comparative analysis is carried out through adoption of a common conceptual model. The similarity and differences between the three catchments are explored through evaluation of signatures of streamflow and soil moisture variability, and systematic sensitivity analysis with respect to parameters representing various landscape characteristics. The results of the analysis show that the biggest contributor to the differences between the catchments is the distribution of soil depth and the soil's drainage characteristics. The second factor is climate, as exemplified by the (annual) climatic dryness index and the intra-annual (seasonal) variability of both rainfall and potential evaporation, and associated rainfall intensity patterns, and their interactions with the soil properties (i.e., soil depth and the soil's drainage characteristics). In Perth and Darwin, climate seasonality is responsible for a seasonal switching on/off of subsurface stormflow at the start/end of the wet season, respectively. In Newcastle, where soil moisture contents hover near the field capacity value throughout the year, subsurface stormflow occurs frequently throughout the year, with event-based switching on/off in response to individual storms of moderate magnitude and temporal clustering of small storms. In addition, in rare circumstance, surface runoff is triggered in response to extreme storm events and temporal clustering of moderate to large storm events.

  15. A conceptual, distributed snow redistribution model

    Science.gov (United States)

    Frey, S.; Holzmann, H.

    2015-11-01

    When applying conceptual hydrological models using a temperature index approach for snowmelt to high alpine areas often accumulation of snow during several years can be observed. Some of the reasons why these "snow towers" do not exist in nature are vertical and lateral transport processes. While snow transport models have been developed using grid cell sizes of tens to hundreds of square metres and have been applied in several catchments, no model exists using coarser cell sizes of 1 km2, which is a common resolution for meso- and large-scale hydrologic modelling (hundreds to thousands of square kilometres). In this paper we present an approach that uses only gravity and snow density as a proxy for the age of the snow cover and land-use information to redistribute snow in alpine basins. The results are based on the hydrological modelling of the Austrian Inn Basin in Tyrol, Austria, more specifically the Ötztaler Ache catchment, but the findings hold for other tributaries of the river Inn. This transport model is implemented in the distributed rainfall-runoff model COSERO (Continuous Semi-distributed Runoff). The results of both model concepts with and without consideration of lateral snow redistribution are compared against observed discharge and snow-covered areas derived from MODIS satellite images. By means of the snow redistribution concept, snow accumulation over several years can be prevented and the snow depletion curve compared with MODIS (Moderate Resolution Imaging Spectroradiometer) data could be improved, too. In a 7-year period the standard model would lead to snow accumulation of approximately 2900 mm SWE (snow water equivalent) in high elevated regions whereas the updated version of the model does not show accumulation and does also predict discharge with more accuracy leading to a Kling-Gupta efficiency of 0.93 instead of 0.9. A further improvement can be shown in the comparison of MODIS snow cover data and the calculated depletion curve, where

  16. River water quality modelling in developing a catchment water safety plan

    OpenAIRE

    Vieira, J. M. Pereira; Pinho, José L. S.

    2014-01-01

    The primary aim of a catchment water safety plan is to reduce risks within the catchment to protect the quality of drinking water sources at the intake point. Even where effective arrangements for catchment management and control have been implemented, unexpected deterioration in raw water quality can pose a risk to treated drinking water quality. Thus potential sources of pollution impacting the area of influence of the intake should be identified and monitored. An important part of any catc...

  17. The limits of splitting: a framework to test model spatial distribution

    Science.gov (United States)

    Lobligeois, F.; Andréassian, V.; Perrin, C.; Loumagne, C.

    2012-04-01

    When it comes to deciding of the necessary spatial representation of a catchment, hydrologists need to choose between spatially lumped and spatially distributed approaches. This decision is not trivial: on the one hand, lumped models have proved both efficient and robust over the years (moreover their relatively low number of parameters limits the numerical problems such as secondary optima, parameter interaction, poor sensitivity); on the other hand many hydrologists believe that distributed models could potentially have a greater ability to take into account the spatial heterogeneity of both rainfall and land surface. Few attempts have been made to test rigorously alternative distributed schemes (see the discussion of semi-lumped and semi-distributed alternatives in Andréassian et al. (2004)). The purpose of our work was to identify whether an optimum level of spatialisation exists: to investigate "the limits of splitting" (Beven, 1996). We propose a framework to evaluate the effect of the distribution over a large set of 181 French catchments, using a newly available high resolution rainfall product of Météo France, combining radar data and raingage measurements. Five grid sizes are studied, as catchments are splitted into 1, 2, 4, 8 and 16 sub-catchments and streamflow simulation results are analysed in validation mode. For each type of basin, we study the trend of model efficiency with the number of sub-catchments. We find paradoxical results: while some catchments clearly benefit from the distribution, others show opposite trends. The large variability between basins underlines the necessity to have enough case studies to reach a robust conclusion. Andréassian, V. et al., 2004. Impact of spatial aggregation of inputs and parameters on the efficiency of rainfall-runoff models: a theoretical study using chimera watersheds. Water Resour. Res., 40(5): W05209, doi: 10.1029/2003WR002854. Beven, K., 1996. The limits of splitting: hydrology. The Science of the

  18. Models of distributive justice.

    Science.gov (United States)

    Wolff, Jonathan

    2007-01-01

    Philosophical disagreement about justice rages over at least two questions. The most immediate is a substantial question, concerning the conditions under which particular distributive arrangements can be said to be just or unjust. The second, deeper, question concerns the nature of justice itself. What is justice? Here we can distinguish three views. First, justice as mutual advantage sees justice as essentially a matter of the outcome of a bargain. There are times when two parties can both be better off by making some sort of agreement. Justice, on this view, concerns the distribution of the benefits and burdens of the agreement. Second, justice as reciprocity takes a different approach, looking not at bargaining but at the idea of a fair return or just price, attempting to capture the idea of justice as equal exchange. Finally justice as impartiality sees justice as 'taking the other person's point of view' asking 'how would you like it if it happened to you?' Each model has significantly different consequences for the question of when issues of justice arise and how they should be settled. It is interesting to consider whether any of these models of justice could regulate behaviour between non-human animals.

  19. Importance of including small-scale tile drain discharge in the calibration of a coupled groundwater-surface water catchment model

    DEFF Research Database (Denmark)

    Hansen, Anne Lausten; Refsgaard, Jens Christian; Christensen, Britt Stenhøj Baun;

    2013-01-01

    the catchment. In this study, a coupled groundwater-surface water model based on the MIKE SHE code was developed for the 4.7 km2 Lillebæk catchment in Denmark, where tile drain flow is a major contributor to the stream discharge. The catchment model was calibrated in several steps by incrementally including...... the observation data into the calibration to see the effect on model performance of including diverse data types, especially tile drain discharge. For the Lillebæk catchment, measurements of hydraulic head, daily stream discharge, and daily tile drain discharge from five small (1–4 ha) drainage areas exist....... The results showed that including tile drain data in the calibration of the catchment model improved its general performance for hydraulic heads and stream discharges. However, the model failed to correctly describe the local-scale dynamics of the tile drain discharges, and, furthermore, including the drain...

  20. Stakeholder discourse and water management – implementation of the participatory model CATCH in a Northern Italian alpine sub-catchment

    Directory of Open Access Journals (Sweden)

    D. Collentine

    2008-03-01

    Full Text Available The Water Framework Directive (WFD, directive 2000/60/EC was created to ensure the sustainable use of water resources in the European Union. A central guideline included throughout the directive is a call for the participation of stakeholders in the management of these resources. Involving stakeholders is an important step to ensure that catchment management plans take into consideration local experience in the development of these plans and the impact of the plans on local interests. This paper describes and analyses the results of a series of workshops to facilitate implementation of the WFD at a catchment level based on the stakeholder participation model, CATCH. To test the usefulness of the CATCH model, developed for water management in a ca