WorldWideScience

Sample records for groundwater level response

  1. Response of the microbial community to seasonal groundwater level fluctuations in petroleum hydrocarbon-contaminated groundwater.

    Science.gov (United States)

    Zhou, Ai-xia; Zhang, Yu-ling; Dong, Tian-zi; Lin, Xue-yu; Su, Xiao-si

    2015-07-01

    The effects of seasonal groundwater level fluctuations on the contamination characteristics of total petroleum hydrocarbons (TPH) in soils, groundwater, and the microbial community were investigated at a typical petrochemical site in northern China. The measurements of groundwater and soil at different depths showed that significant TPH residue was present in the soil in this study area, especially in the vicinity of the pollution source, where TPH concentrations were up to 2600 mg kg(-1). The TPH concentration in the groundwater fluctuated seasonally, and the maximum variation was 0.8 mg L(-1). The highest TPH concentrations were detected in the silty clay layer and lied in the groundwater level fluctuation zones. The groundwater could reach previously contaminated areas in the soil, leading to higher groundwater TPH concentrations as TPH leaches into the groundwater. The coincident variation of the electron acceptors and TPH concentration with groundwater-table fluctuations affected the microbial communities in groundwater. The microbial community structure was significantly different between the wet and dry seasons. The canonical correspondence analysis (CCA) results showed that in the wet season, TPH, NO3(-), Fe(2+), TMn, S(2-), and HCO3(-) were the major factors correlating the microbial community. A significant increase in abundance of operational taxonomic unit J1 (97% similar to Dechloromonas aromatica sp.) was also observed in wet season conditions, indicating an intense denitrifying activity in the wet season environment. In the dry season, due to weak groundwater level fluctuations and low temperature of groundwater, the microbial activity was weak. But iron and sulfate-reducing were also detected in dry season at this site. As a whole, groundwater-table fluctuations would affect the distribution, transport, and biodegradation of the contaminants. These results may be valuable for the control and remediation of soil and groundwater pollution at this site

  2. Groundwater level responses to precipitation variability in Mediterranean insular aquifers

    Science.gov (United States)

    Lorenzo-Lacruz, Jorge; Garcia, Celso; Morán-Tejeda, Enrique

    2017-09-01

    Groundwater is one of the largest and most important sources of fresh water on many regions under Mediterranean climate conditions, which are exposed to large precipitation variability that includes frequent meteorological drought episodes, and present high evapotranspiration rates and water demand during the dry season. The dependence on groundwater increases in those areas with predominant permeable lithologies, contributing to aquifer recharge and the abundance of ephemeral streams. The increasing pressure of tourism on water resources in many Mediterranean coastal areas, and uncertainty related to future precipitation and water availability, make it urgent to understand the spatio-temporal response of groundwater bodies to precipitation variability, if sustainable use of the resource is to be achieved. We present an assessment of the response of aquifers to precipitation variability based on correlations between the Standardized Precipitation Index (SPI) at various time scales and the Standardized Groundwater Index (SGI) across a Mediterranean island. We detected three main responses of aquifers to accumulated precipitation anomalies: (i) at short time scales of the SPI (24 months). The differing responses were mainly explained by differences in lithology and the percentage of highly permeable rock strata in the aquifer recharge areas. We also identified differences in the months and seasons when aquifer storages are more dependent on precipitation; these were related to climate seasonality and the degree of aquifer exploitation or underground water extraction. The recharge of some aquifers, especially in mountainous areas, is related to precipitation variability within a limited spatial extent, whereas for aquifers located in the plains, precipitation variability influence much larger areas; the topography and geological structure of the island explain these differences. Results indicate large spatial variability in the response of aquifers to precipitation in

  3. Response of groundwater level and surface-water/groundwater interaction to climate variability: Clarence-Moreton Basin, Australia

    Science.gov (United States)

    Cui, Tao; Raiber, Matthias; Pagendam, Dan; Gilfedder, Mat; Rassam, David

    2017-08-01

    Understanding the response of groundwater levels in alluvial and sedimentary basin aquifers to climatic variability and human water-resource developments is a key step in many hydrogeological investigations. This study presents an analysis of groundwater response to climate variability from 2000 to 2012 in the Queensland part of the sedimentary Clarence-Moreton Basin, Australia. It contributes to the baseline hydrogeological understanding by identifying the primary groundwater flow pattern, water-level response to climate extremes, and the resulting dynamics of surface-water/groundwater interaction. Groundwater-level measurements from thousands of bores over several decades were analysed using Kriging and nonparametric trend analysis, together with a newly developed three-dimensional geological model. Groundwater-level contours suggest that groundwater flow in the shallow aquifers shows local variations in the close vicinity of streams, notwithstanding general conformance with topographic relief. The trend analysis reveals that climate variability can be quickly reflected in the shallow aquifers of the Clarence-Moreton Basin although the alluvial aquifers have a quicker rainfall response than the sedimentary bedrock formations. The Lockyer Valley alluvium represents the most sensitively responding alluvium in the area, with the highest declining (-0.7 m/year) and ascending (2.1 m/year) Sen's slope rates during and after the drought period, respectively. Different surface-water/groundwater interaction characteristics were observed in different catchments by studying groundwater-level fluctuations along hydrogeologic cross-sections. The findings of this study lay a foundation for future water-resource management in the study area.

  4. Effect of Different Groundwater Levels on Seismic Dynamic Response and Failure Mode of Sandy Slope.

    Directory of Open Access Journals (Sweden)

    Shuai Huang

    Full Text Available Heavy seismic damage tends to occur in slopes when groundwater is present. The main objectives of this paper are to determine the dynamic response and failure mode of sandy slope subjected simultaneously to seismic forces and variable groundwater conditions. This paper applies the finite element method, which is a fast and efficient design tool in modern engineering analysis, to evaluate dynamic response of the slope subjected simultaneously to seismic forces and variable groundwater conditions. Shaking table test is conducted to analyze the failure mode and verify the accuracy of the finite element method results. The research results show that dynamic response values of the slope have different variation rules under near and far field earthquakes. And the damage location and pattern of the slope are different in varying groundwater conditions. The destruction starts at the top of the slope when the slope is in no groundwater, which shows that the slope appears obvious whipping effect under the earthquake. The destruction starts at the toe of the slope when the slope is in the high groundwater levels. Meanwhile, the top of the slope shows obvious seismic subsidence phenomenon after earthquake. Furthermore, the existence of the groundwater has a certain effect of damping.

  5. Effect of Different Groundwater Levels on Seismic Dynamic Response and Failure Mode of Sandy Slope

    Science.gov (United States)

    Huang, Shuai; Lv, Yuejun; Peng, Yanju; Zhang, Lifang; Xiu, Liwei

    2015-01-01

    Heavy seismic damage tends to occur in slopes when groundwater is present. The main objectives of this paper are to determine the dynamic response and failure mode of sandy slope subjected simultaneously to seismic forces and variable groundwater conditions. This paper applies the finite element method, which is a fast and efficient design tool in modern engineering analysis, to evaluate dynamic response of the slope subjected simultaneously to seismic forces and variable groundwater conditions. Shaking table test is conducted to analyze the failure mode and verify the accuracy of the finite element method results. The research results show that dynamic response values of the slope have different variation rules under near and far field earthquakes. And the damage location and pattern of the slope are different in varying groundwater conditions. The destruction starts at the top of the slope when the slope is in no groundwater, which shows that the slope appears obvious whipping effect under the earthquake. The destruction starts at the toe of the slope when the slope is in the high groundwater levels. Meanwhile, the top of the slope shows obvious seismic subsidence phenomenon after earthquake. Furthermore, the existence of the groundwater has a certain effect of damping. PMID:26560103

  6. Effect of Different Groundwater Levels on Seismic Dynamic Response and Failure Mode of Sandy Slope.

    Science.gov (United States)

    Huang, Shuai; Lv, Yuejun; Peng, Yanju; Zhang, Lifang; Xiu, Liwei

    2015-01-01

    Heavy seismic damage tends to occur in slopes when groundwater is present. The main objectives of this paper are to determine the dynamic response and failure mode of sandy slope subjected simultaneously to seismic forces and variable groundwater conditions. This paper applies the finite element method, which is a fast and efficient design tool in modern engineering analysis, to evaluate dynamic response of the slope subjected simultaneously to seismic forces and variable groundwater conditions. Shaking table test is conducted to analyze the failure mode and verify the accuracy of the finite element method results. The research results show that dynamic response values of the slope have different variation rules under near and far field earthquakes. And the damage location and pattern of the slope are different in varying groundwater conditions. The destruction starts at the top of the slope when the slope is in no groundwater, which shows that the slope appears obvious whipping effect under the earthquake. The destruction starts at the toe of the slope when the slope is in the high groundwater levels. Meanwhile, the top of the slope shows obvious seismic subsidence phenomenon after earthquake. Furthermore, the existence of the groundwater has a certain effect of damping.

  7. Atoll groundwater movement and its response to climatic and sea-level fluctuations

    Science.gov (United States)

    Oberle, Ferdinand; Swarzenski, Peter; Storlazzi, Curt

    2017-01-01

    Groundwater resources of low-lying atoll islands are threatened due to short-term and long-term changes in rainfall, wave climate, and sea level. A better understanding of how these forcings affect the limited groundwater resources was explored on Roi-Namur in the Republic of the Marshall Islands. As part of a 16-month study, a rarely recorded island-overwash event occurred and the island’s aquifer’s response was measured. The findings suggest that small-scale overwash events cause an increase in salinity of the freshwater lens that returns to pre-overwash conditions within one month. The overwash event is addressed in the context of climate-related local sea-level change, which suggests that overwash events and associated degradations in freshwater resources are likely to increase in severity in the future due to projected rises in sea level. Other forcings, such as severe rainfall events, were shown to have caused a sudden freshening of the aquifer, with salinity levels retuning to pre-rainfall levels within three months. Tidal forcing of the freshwater lens was observed in electrical resistivity profiles, high-resolution conductivity, groundwater-level well measurements and through submarine groundwater discharge calculations. Depth-specific geochemical pore water measurements further assessed and confirmed the distinct boundaries between fresh and saline water masses in the aquifer. The identification of the freshwater lens’ saline boundaries is essential for a quantitative evaluation of the aquifers freshwater resources and help understand how these resources may be impacted by climate change and anthropogenic activities.

  8. Plant traits in response to raising groundwater levels in wetland restoration: evidence from three case studies

    NARCIS (Netherlands)

    Bodegom, van P.M.; Grootjans, A.P.; Sorrell, B.K.; Bekker, R.M.; Bakker, C.; Ozinga, W.A.

    2006-01-01

    Question: Is raising groundwater tables successful as a wetland restoration strategy? Location: Kennemer dunes, The Netherlands; Moksloot dunes, The Netherlands and Bullock Creek fen, New Zealand. Methods: Generalizations were made by analysing soil dynamics and the responsiveness of integrative pla

  9. Plant traits in response to raising groundwater levels in wetland restoration : evidence from three case studies

    NARCIS (Netherlands)

    Bodegom, P.M. van; Grootjans, A.P.; Sorrell, B.K.; Bekker, R.M.; Bakker, C.; Ozinga, W.A.; Middleton, B.

    2006-01-01

    Question: Is raising groundwater tables successful as a wetland restoration strategy? Location: Kennemer dunes, The Netherlands; Moksloot dunes, The Netherlands and Bullock Creek fen, New Zealand. Methods: Generalizations were made by analysing soil dynamics and the responsiveness of integrative pla

  10. Groundwater level response in U.S. Principal Aquifers to natural climate variability on interannual to multidecadal timescales

    Science.gov (United States)

    Velasco, E.; Gurdak, J. J.; Dickinson, J.; Hanson, R. T.; Ferré, T. P. A.; Maurer, E. P.

    2014-12-01

    Natural climate variability on interannual to multidecadal timescales are important controls on precipitation, drought, evapotranspiration, streamflow, and groundwater recharge. Climate variability can also augment or diminish human stresses on water resources. Thus, understanding climate variability has particular relevance for groundwater management. Findings will be presented from a national scale study of groundwater level response to natural climate variability in principal aquifers (PAs) of the U.S., including the California Coastal Basin, Rio Grande, Coastal Lowlands, Mississippi Embayment, Floridan, and Glacial aquifer systems. We use the U.S. Geological Survey hydroclimatic analysis toolkit HydroClimATe to perform singular spectrum analysis and identify quasi-periodic signals in precipitation and groundwater time series that are coincident with the Arctic Oscillation (AO) (6-12 mo cycle), Pacific/North American oscillation (PNA) (management and planning decisions about the locations, cost effectiveness, and optimal time periods for conjunctive use strategies.

  11. Physiological response of natural plants to the change of groundwater level in the lower reaches of Tarim River,Xinjiang

    Institute of Scientific and Technical Information of China (English)

    CHEN Yaning; LI Weihong; CHEN Yapeng; ZHANG Hongfeng; ZHUANG Li

    2004-01-01

    Based on the analysis of the three-year (2000-2002) monitoring data of the four times intermittent stream water conveyance to the lower reaches of Tarim River where the stream flow was dried up for more than 30 years and the measurement of PRO, SOD and POD in plants collected from 24 vegetation plots, it is concluded that the stream water conveyance plays an important role in lifting groundwater level. The groundwater nearby the watercourse was raised from 5~8 m in depth before the stream water conveyance to 2.5~5 m after stream water conveyance. The physiological response of Phragmites communis, Tamarix spp. And Populus euphratica to the change of groundwater is sensitive and represents a grads change obviously. The growth of the plants in the lower reaches of Tarim River is stressed by drought to various degrees. Lengthways, the drought stress exposed to the plants increases with groundwater depth from the upper sections to the lower sections; and breadthwise, the drought stress exposed to the plants is increased with the increase of distance away from the river channel of stream intermittent water releases and of the groundwater depth. Combining the field investigation and the analysis of the plots, it is considered that the stress groundwater depths for the Phragmites communis, Tamarix spp. And Populus euphratica are 3.5 m, 5 m and 4.5 m respectively.

  12. Modelling the response of shallow groundwater levels to combined climate and water-diversion scenarios in Beijing-Tianjin-Hebei Plain, China

    Science.gov (United States)

    Li, Xue; Ye, Si-Yuan; Wei, Ai-Hua; Zhou, Peng-Peng; Wang, Li-Heng

    2017-09-01

    A three-dimensional groundwater flow model was implemented to quantify the temporal variation of shallow groundwater levels in response to combined climate and water-diversion scenarios over the next 40 years (2011-2050) in Beijing-Tianjin-Hebei (Jing-Jin-Ji) Plain, China. Groundwater plays a key role in the water supply, but the Jing-Jin-Ji Plain is facing a water crisis. Groundwater levels have declined continuously over the last five decades (1961-2010) due to extensive pumping and climate change, which has resulted in decreased recharge. The implementation of the South-to-North Water Diversion Project (SNWDP) will provide an opportunity to restore the groundwater resources. The response of groundwater levels to combined climate and water-diversion scenarios has been quantified using a groundwater flow model. The impacts of climate change were based on the World Climate Research Programme's (WCRP's) Coupled Model Intercomparison Project phase 3 (CMIP3) multi-model dataset for future high (A2), medium (A1B), and low (B1) greenhouse gas scenarios; precipitation data from CMIP3 were applied in the model. The results show that climate change will slow the rate of decrease of the shallow groundwater levels under three climate-change scenarios over the next 40 years compared to the baseline scenario; however, the shallow groundwater levels will rise significantly (maximum of 6.71 m) when considering scenarios that combine climate change and restrictions on groundwater exploitation. Restrictions on groundwater exploitation for water resource management are imperative to control the decline of levels in the Jing-Jin-Ji area.

  13. Modelling the response of shallow groundwater levels to combined climate and water-diversion scenarios in Beijing-Tianjin-Hebei Plain, China

    Science.gov (United States)

    Li, Xue; Ye, Si-Yuan; Wei, Ai-Hua; Zhou, Peng-Peng; Wang, Li-Heng

    2017-03-01

    A three-dimensional groundwater flow model was implemented to quantify the temporal variation of shallow groundwater levels in response to combined climate and water-diversion scenarios over the next 40 years (2011-2050) in Beijing-Tianjin-Hebei (Jing-Jin-Ji) Plain, China. Groundwater plays a key role in the water supply, but the Jing-Jin-Ji Plain is facing a water crisis. Groundwater levels have declined continuously over the last five decades (1961-2010) due to extensive pumping and climate change, which has resulted in decreased recharge. The implementation of the South-to-North Water Diversion Project (SNWDP) will provide an opportunity to restore the groundwater resources. The response of groundwater levels to combined climate and water-diversion scenarios has been quantified using a groundwater flow model. The impacts of climate change were based on the World Climate Research Programme's (WCRP's) Coupled Model Intercomparison Project phase 3 (CMIP3) multi-model dataset for future high (A2), medium (A1B), and low (B1) greenhouse gas scenarios; precipitation data from CMIP3 were applied in the model. The results show that climate change will slow the rate of decrease of the shallow groundwater levels under three climate-change scenarios over the next 40 years compared to the baseline scenario; however, the shallow groundwater levels will rise significantly (maximum of 6.71 m) when considering scenarios that combine climate change and restrictions on groundwater exploitation. Restrictions on groundwater exploitation for water resource management are imperative to control the decline of levels in the Jing-Jin-Ji area.

  14. Cross-species toxicogenomic analyses and phenotypic anchoring in response to groundwater low-level pollution.

    Science.gov (United States)

    Porreca, Immacolata; D'Angelo, Fulvio; Gentilcore, Daniela; Carchia, Emanuele; Amoresano, Angela; Affuso, Andrea; Ceccarelli, Michele; De Luca, Pasquale; Esposito, Libera; Guadagno, Francesco M; Mallardo, Massimo; Nardone, Antonio; Maccarone, Sergio; Pane, Francesca; Scarfò, Marzia; Sordino, Paolo; De Felice, Mario; Ambrosino, Concetta

    2014-12-05

    Comparison of toxicogenomic data facilitates the identification of deregulated gene patterns and maximizes health risk prediction in human. Here, we performed phenotypic anchoring on the effects of acute exposure to low-grade polluted groundwater using mouse and zebrafish. Also, we evaluated two windows of chronic exposure in mouse, starting in utero and at the end of lactation. Bioinformatic analysis of livers microarray data showed that the number of deregulated biofunctions and pathways is higher after acute exposure, compared to the chronic one. It also revealed specific profiles of altered gene expression in all treatments, pointing to stress response/mitochondrial pathways as major players of environmental toxicity. Of note, dysfunction of steroid hormones was also predicted by bioinformatic analysis and verified in both models by traditional approaches, serum estrogens measurement and vitellogenin mRNA determination in mice and zebrafish, respectively. In our report, phenotypic anchoring in two vertebrate model organisms highlights the toxicity of low-grade pollution, with varying susceptibility based on exposure window. The overlay of zebrafish and mice deregulated pathways, more than single genes, is useful in risk identification from chemicals implicated in the observed effects.

  15. Temporal and spatial variability response of groundwater level to land use/land cover change in oases of arid areas

    Institute of Scientific and Technical Information of China (English)

    YAN Jinfeng; CHEN Xi; LUO Geping; GUO Quanjun

    2006-01-01

    This paper conducts a case study on the impacts of land use/cover change (LUCC) on the temporal and spatial variability of the groundwater level in an arid oasis in the Sangong River Watershed by using the geographical information system (GIS),remote sensing (RS) and geostatistical methods. The temporal and spatial variability of the groundwater level in the watershed in 1978, 1987 and 1998 is regressed by using thesemivariogram model and Kriging interpolation. The LUCC classification maps derived from the aerial images in 1978, Landsat TM image in 1987 and Landsat ETM image in 1998 are used to superpose and analyze the conversion relationship of LUCC types in the regions with different isograms of the groundwater depth. The results show that the change of groundwater recharge was not so significant in the whole oasis, but the temporal and spatial LUCC was significant either in the normal flow periods or in the high flow periods during the 20-year period from 1978 to 1998, and there was a close correlation between them. There is generally a moderate spatial correlation of groundwater level (33.4%),and the spatial autocorrelation distance is 17.78 km.The regions where the groundwater level is sharply changed are also the regions where the land resources are increasingly exploited, which include mainly the exploitation of farmlands, woodlands, and building, industrial and mining lands. The study reveals that the LUCC affects strongly the temporal and spatial variability of the groundwater level in the arid oasis. The study results are of direct and practical significance for rationally utilizing shallow groundwater resources and maintaining the stability of the arid oasis.

  16. Coseismic responses of groundwater levels in the Three Gorges well-network to the Wenchuan Ms8.0 earthquake

    Institute of Scientific and Technical Information of China (English)

    Chenglong Liu; Guangcai Wang; Weihua Zhang; Jiangchang Mei

    2009-01-01

    We systematically analyze coseismic responses and post-seismic characteristics of groundwater levels in the Three Gorges well-network to the Afs8.0 Wenchuan earthquake on 12 May 2008. The results indicate that these characteristics differ among wells. On the conditions of similar borehole configurations, the differences are associated with geological structural sites of wells, burial types of aquifers monitored, and transmissivities of aquifer systems. We explored coseismic and post-seismic step-rise and step-drop mechanical mechanisms and their implication to earthquake prediction. We validated the inference that the residual step-rise zone is a possible earthquake risk zone based on recent seismic activity on the Xianniishan fault in the area.

  17. Groundwater level status report for 2010, Los Alamos National Laboratory

    Energy Technology Data Exchange (ETDEWEB)

    Koch, Richard J.; Schmeer, Sarah

    2011-03-01

    The status of groundwater level monitoring at Los Alamos National Laboratory in 2010 is provided in this report. This report summarizes groundwater level data for 194 monitoring wells, including 63 regional aquifer wells (including 10 regional/intermediate wells), 34 intermediate wells, 97 alluvial wells, and 12 water supply wells. Pressure transducers were installed in 162 monitoring wells for continuous monitoring of groundwater levels. Time-series hydrographs of groundwater level data are presented along with pertinent construction and location information for each well. The report also summarizes the groundwater temperatures recorded in intermediate and regional aquifer monitoring wells and seasonal responses to snowmelt runoff observed in intermediate wells.

  18. Examining the Relationship between Drought Indices and Groundwater Levels

    OpenAIRE

    Navaratnam Leelaruban; Padmanabhan, G.; Peter Oduor

    2017-01-01

    Thorough characterization of the response of finite water resources to climatic factors is essential for water monitoring and management. In this study, groundwater level data from U.S. Geological Survey Ground-Water Climate Response Network wells were used to analyze the relationship between selected drought indices and groundwater level fluctuation. The drought episodes included in this study were selected using climate division level drought indices. Indices included the Palmer Drought Sev...

  19. Changes in groundwater levels and the response of natural vegetation to transfer of water to the lower reaches of the Tarim River

    Institute of Scientific and Technical Information of China (English)

    2007-01-01

    Restoration and reconstruction of the degraded Tarim River ecosystem is an important challenge. A goal of an ecological water conveyance project is to protect and restore the natural vegetation in the lower reaches of Tarim River by transferring water from Bosten Lake, through the river channel, to the lower reaches. This study describes the changes in groundwater depth during the water transfer and the respondence of riparian vegetation to alterations in groundwater levels. The results indicate that groundwater depth along the Tarim River channel has a significant spatial-temporal component. Groundwater levels closest to the river channel show the most immediate and pronounced changes as a response to water transfer while those further away respond more slowly, although the observed change appears to be longer in duration. With a rise in the groundwater level, natural vegetation responded with higher growth rates, biomass and biodiversity. These favorable changes show that it is feasible to protect and restore the degraded natural vegetation by raising the groundwater depth. Plant communities are likely to reflect the hysteresis phenomenon, requiring higher water levels to initiate and stimulate desired growth than what may be needed to maintain the plant community. Because different species have different ecologies, including different root depths and densities and water needs, their response to increasing water availability will be spatially and temporally heterogenous. The response of vegetation is also influenced by microtopography and watering style. This paper discusses strategies for the protection and restoration of the degraded vegetation in the lower reaches of the Tarim River and provides information to complement ongoing theoretical research into ecological restoration in arid or semi-arid ecosystems.

  20. Examining the Relationship between Drought Indices and Groundwater Levels

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    Navaratnam Leelaruban

    2017-01-01

    Full Text Available Thorough characterization of the response of finite water resources to climatic factors is essential for water monitoring and management. In this study, groundwater level data from U.S. Geological Survey Ground-Water Climate Response Network wells were used to analyze the relationship between selected drought indices and groundwater level fluctuation. The drought episodes included in this study were selected using climate division level drought indices. Indices included the Palmer Drought Severity Index, Palmer Hydrological Drought Index, and Standardized Precipitation Index (SPI-6, 9, 12, 24. Precipitation and the average temperature were also used. SPI-24 was found to correlate best with groundwater levels during drought. For 17 out of 32 wells, SPI-24 showed the best correlation amongst all of the indices. For 12 out of 32 wells, SPI-24 showed correlation coefficients of −0.6 or stronger; and for other wells, reasonably good correlation was demonstrated. The statistical significance of SPI-24 in predicting groundwater level was also tested. The correlation of average monthly groundwater levels with SPI-24 does not change much throughout the timeframe, for all of the studied wells. The duration of drought also had a significant correlation with the decline of groundwater levels. This study illustrates how drought indices can be used for a rapid assessment of drought impact on groundwater level.

  1. Groundwater Level Predictions Using Artificial Neural Networks

    Institute of Scientific and Technical Information of China (English)

    毛晓敏; 尚松浩; 刘翔

    2002-01-01

    The prediction of groundwater level is important for the use and management of groundwater resources. In this paper, the artificial neural networks (ANN) were used to predict groundwater level in the Dawu Aquifer of Zibo in Eastern China. The first step was an auto-correlation analysis of the groundwater level which showed that the monthly groundwater level was time dependent. An auto-regression type ANN (ARANN) model and a regression-auto-regression type ANN (RARANN) model using back-propagation algorithm were then used to predict the groundwater level. Monthly data from June 1988 to May 1998 was used for the network training and testing. The results show that the RARANN model is more reliable than the ARANN model, especially in the testing period, which indicates that the RARANN model can describe the relationship between the groundwater fluctuation and main factors that currently influence the groundwater level. The results suggest that the model is suitable for predicting groundwater level fluctuations in this area for similar conditions in the future.

  2. Data-Driven Techniques for Regional Groundwater Level Forecasts

    Science.gov (United States)

    Chang, F. J.; Chang, L. C.; Tsai, F. H.; Shen, H. Y.

    2015-12-01

    Data-Driven Techniques for Regional Groundwater Level Forecasts Fi-John Changa, Li-Chiu Changb, Fong He Tsaia, Hung-Yu Shenba Department of Bioenvironmental Systems Engineering, National Taiwan University, Taipei 10617, Taiwan, ROC. b Department of Water Resources and Environmental Engineering, Tamkang University, New Taipei City 25137, Taiwan, ROC..Correspondence to: Fi-John Chang (email: changfj@ntu.edu.tw)The alluvial fan of the Zhuoshui River in Taiwan is a good natural recharge area of groundwater. However, the over extraction of groundwater occurs in the coastland results in serious land subsidence. Groundwater systems are heterogeneous with diverse temporal-spatial patterns, and it is very difficult to quantify their complex processes. Data-driven methods can effectively capture the spatial-temporal characteristics of input-output patterns at different scales for accurately imitating dynamic complex systems with less computational requirements. In this study, we implement various data-driven methods to suitably predict the regional groundwater level variations for making countermeasures in response to the land subsidence issue in the study area. We first establish the relationship between regional rainfall, streamflow as well as groundwater levels and then construct intelligent groundwater level prediction models for the basin based on the long-term (2000-2013) regional monthly data sets collected from the Zhuoshui River basin. We analyze the interaction between hydrological factors and groundwater level variations; apply the self-organizing map (SOM) to obtain the clustering results of the spatial-temporal groundwater level variations; and then apply the recurrent configuration of nonlinear autoregressive with exogenous inputs (R-NARX) to predicting the monthly groundwater levels. As a consequence, a regional intelligent groundwater level prediction model can be constructed based on the adaptive results of the SOM. Results demonstrate that the development

  3. Response of the accumulation of proline in the bodies of Populus euphratica to the change of groundwater level at the lower reaches of Tarim River

    Institute of Scientific and Technical Information of China (English)

    CHEN Yaning; CHEN Yapeng; LI Weihong; ZHANG Hongfeng

    2003-01-01

    The content of proline in the plant bodies is closely related to the converse-succession-resistant capability of the plants. In this paper, the relationship between the proline accumulation in the bodies of Populus euphratica and the change of groundwater level is analyzed by taking Populus euphratica, the main community-building species of the desert riparian forests along the Tarim River, as the research object. The research results show that the accumulation of proline in the bodies of Populus euphratica is closely related to the change of groundwater level gradient under drought stress, it increases with the drawdown of groundwater level and the increase of moisture stress degree; the accumulation of proline in the bodies of Populus euphratica has two extremely high points at the groundwater depth ranges of 3.64-5.14 m and 9.46-10.16 m. Combining the field investigation and the analysis of the plots, it is considered that the groundwater level of 3.5-4.5 m is rational for the growth of Populus euphratica. The stress groundwater depth for the normal growth and the critical one for the survival of Populus euphratica are below 4.5 m and 9-10 m respectively at the lower reaches of the Tarim River.

  4. Global Climate Responses to Anthropogenic Groundwater Exploitation

    Science.gov (United States)

    Zeng, Y.; Xie, Z.

    2015-12-01

    In this study, a groundwater exploitation scheme is incorporated into the earth system model, Community Earth System Model 1.2.0 (CESM1.2.0), which is called CESM1.2_GW, and the climatic responses to anthropogenic groundwater withdrawal are then investigated on global scale. The scheme models anthropogenic groundwater exploitation and consumption, which are then divided into agricultural irrigation, industrial use and domestic use. A group of 41-year ensemble groundwater exploitation simulations with six different initial conditions, and a group of ensemble control simulations without exploitation are conducted using the developed model CESM1.2_GW with water supplies and demands estimated. The results reveal that the groundwater exploitation and water consumption cause drying effects on soil moisture in deep layers and wetting effects in upper layers, along with a rapidly declining groundwater table in Central US, Haihe River Basin in China and Northern India and Pakistan where groundwater extraction are most severe in the world. The atmosphere also responds to anthropogenic groundwater exploitation. Cooling effects on lower troposphere appear in large areas of North China Plain and of Northern India and Pakistan. Increased precipitation occurs in Haihe River Basin due to increased evapotranspiration from irrigation. Decreased precipitation occurs in Northern India because water vapor here is taken away by monsoon anomalies induced by anthropogenic alteration of groundwater. The local reducing effects of anthropogenic groundwater exploitation on total terrestrial water storage evinces that water resource is unsustainable with the current high exploitation rate. Therefore, a balance between slow groundwater withdrawal and rapid human economic development must be achieved to maintain a sustainable water resource, especially in over-exploitation regions such as Central US, Northern China, India and Pakistan.

  5. Groundwater Level Status Report for 2005 Los Alamos National Laboratory

    Energy Technology Data Exchange (ETDEWEB)

    S.P. Allen; R.J. Koch

    2006-05-15

    The status of groundwater level monitoring at Los Alamos National Laboratory (LANL) in 2005 is provided in this report. The Groundwater Level Monitoring Project was instituted in 2005 to provide a framework for the collection and processing of quality controlled groundwater level data. This report summarizes groundwater level data for 137 monitoring wells, including 41 regional aquifer wells, 22 intermediate wells, and 74 alluvial wells. Pressure transducers were installed in 118 monitoring wells for continuous monitoring of groundwater levels. Time-series hydrographs of groundwater level data are presented along with pertinent construction and location information for each well.

  6. Groundwater level changes in a deep well in response to a magma intrusion event on Kilauea Volcano, Hawai'i

    Science.gov (United States)

    Hurwitz, S.; Johnston, M.J.S.

    2003-01-01

    On May 21, 2001, an abrupt inflation of Kilauea Volcano's summit induced a rapid and large increase in compressional strain, with a maximum of 2 ??strain recorded by a borehole dilatometer. Water level (pressure) simultaneously dropped by 6 cm. This mode of water level change (drop) is in contrast to that expected for compressional strain from poroelastic theory, and therefore it is proposed that the stress applied by the intrusion has caused opening of fractures or interflows that drained water out of the well. Upon relaxation of the stress recorded by the dilatometer, water levels have recovered at a similar rate. The proposed model has implications for the analysis of ground surface deformation and for mechanisms that trigger phreatomagmatic eruptions.

  7. Groundwater levels for selected wells in Upper Kittitas County, Washington

    Science.gov (United States)

    Fasser, E.T.; Julich, R.J.

    2011-01-01

    Groundwater levels for selected wells in Upper Kittitas County, Washington, are presented on an interactive, web-based map to document the spatial distribution of groundwater levels in the study area measured during spring 2011. Groundwater-level data and well information were collected by the U.S. Geological Survey using standard techniques and are stored in the U.S. Geological Survey National Water Information System, Groundwater Site-Inventory database.

  8. Application of vector autoregressive model for rainfall and groundwater level analysis

    Science.gov (United States)

    Keng, Chai Yoke; Shan, Fam Pei; Shimizu, Kunio; Imoto, Tomoaki; Lateh, Habibah; Peng, Koay Swee

    2017-08-01

    Groundwater is a crucial water supply for industrial, agricultural and residential use, hence it is important to understand groundwater system. Groundwater is a dynamic natural resource and can be recharged. The amount of recharge depends on the rate and duration of rainfall, as rainfall comprises an important component of the water cycle and is the prime source of groundwater recharge. This study applies Vector Autoregressive (VAR) model in the analysis of rainfall and groundwater level. The study area that is focused in the study is along the East-West Highway, Gerik-Jeli, Malaysia. The VAR model with optimum lag length 8, VAR(8) is selected to model the rainfall and groundwater level in the study area. Result of Granger causality test shows significant influence of rainfall to groundwater level. Impulse Response Function reveals that changes in rainfall significantly affect changes in groundwater level after some time lags. Moreover, Variance Decomposition reported that rainfall contributed to the forecast of the groundwater level. The VAR(8) model is validated by comparing the actual value with the in-sample forecasted value and the result is satisfied with all forecasted groundwater level values lies inside the confidence interval which indicate that the model is reliable. Furthermore, the closeness of both actual and forecasted groundwater level time series plots implies the high degree of accurateness of the estimated model.

  9. Groundwater Level Prediction using M5 Model Trees

    Science.gov (United States)

    Nalarajan, Nitha Ayinippully; Mohandas, C.

    2015-01-01

    Groundwater is an important resource, readily available and having high economic value and social benefit. Recently, it had been considered a dependable source of uncontaminated water. During the past two decades, increased rate of extraction and other greedy human actions have resulted in the groundwater crisis, both qualitatively and quantitatively. Under prevailing circumstances, the availability of predicted groundwater levels increase the importance of this valuable resource, as an aid in the planning of groundwater resources. For this purpose, data-driven prediction models are widely used in the present day world. M5 model tree (MT) is a popular soft computing method emerging as a promising method for numeric prediction, producing understandable models. The present study discusses the groundwater level predictions using MT employing only the historical groundwater levels from a groundwater monitoring well. The results showed that MT can be successively used for forecasting groundwater levels.

  10. Groundwater level status report for 2008, Los Alamos National Laboratory

    Energy Technology Data Exchange (ETDEWEB)

    Koch, Richard J.; Schmeer, Sarah

    2009-03-01

    The status of groundwater level monitoring at Los Alamos National Laboratory in 2008 is provided in this report. This report summarizes groundwater level data for 179 monitoring wells, including 45 regional aquifer wells, 28 intermediate wells, 8 regional/intermediate wells, 106 alluvial wells, and 12 water supply wells. Pressure transducers were installed in 166 monitoring wells for continuous monitoring of groundwater levels. Time-series hydrographs of groundwater level data are presented along with pertinent construction and location information for each well. The report also summarizes the groundwater temperatures recorded in intermediate and regional aquifer monitoring wells.

  11. Groundwater level status report for 2009, Los Alamos National Laboratory

    Energy Technology Data Exchange (ETDEWEB)

    Koch, Richard J.; Schmeer, Sarah

    2010-03-01

    The status of groundwater level monitoring at Los Alamos National Laboratory in 2009 is provided in this report. This report summarizes groundwater level data for 179 monitoring wells, including 55 regional aquifer wells (including 11 regional/intermediate wells), 26 intermediate wells, 98 alluvial wells, and 12 water supply wells. Pressure transducers were installed in 161 monitoring wells for continuous monitoring of groundwater levels. Time-series hydrographs of groundwater level data are presented along with pertinent construction and location information for each well. The report also summarizes the groundwater temperatures recorded in intermediate and regional aquifer monitoring wells.

  12. Response of Groundwater Level to Irrigation%地下水水位对灌溉的响应——以北京南部灌区为例

    Institute of Scientific and Technical Information of China (English)

    王树芳; 韩征

    2012-01-01

    Groundwater in Beijing is essential for achieving demand of agriculture irrigation and guaranteeing grain production. However f groundwater level is continuously decreasing with the overexploitation of groundwater. In order to find the response of groundwater level to agriculture irrigation, a monitoring well mainly affected by agriculture irrigation was selected to find out relationship between groundwater and winter wheat irrigation by analyzing relationship between daily change of groundwater level, precipitation and coupling degree between rainfall and water requirement of winter wheat. As concluded from the study, a close relation between groundwater level and winter wheat irrigation was indicated by groundwater level decrease corresponding to every irrigation period. Groundwater rose to the level before winter irrigation when striking root irrigation started due to abundant and effective recharge by precipitation infiltration; however, groundwater level continuously decreases with consumption of static reserve of groundwater due to ineffective and incomplete recharge because irrigation requirement was greater and precipitation was smaller during striking root-jointing stage and filling stage irrigation. Exploitation and compensation balance can be obtained to achieve sustainable development of groundwater if groundwater pump rate is reduced by water saving irrigation methods or alternating water source during striking root-jointing stage and filling stage irrigation.%北京地区的地下水为满足农业灌溉,保障粮食生产起到了至关重要的作用.但是随着开采的急剧增加,地下水位出现了连续下降的趋势.为掌握地下水水位对农业灌溉的响应,选取了主要受农业灌溉影响为主的一眼地下水监测井,通过对比地下水水位的日变化量与大气降水以及本地区冬小麦降水耦合度之间的关系,得出了地下水水位与冬小麦灌溉之间的关系.研究发现,冬小麦灌溉各个阶段

  13. Groundwater: Quality Levels and Human Exposure, SW Nigeria

    Directory of Open Access Journals (Sweden)

    Olusola Adeyemi

    2017-04-01

    Full Text Available Groundwater serves as a source of freshwater for agricultural, industrial and domestic purposes and it accounts for about 42%, 27% and 36% respectively. As it remains the only source of all-year-round supply of freshwater globally, it is of vital importance as regards water security, human survival and sustainable agriculture. The main goal of this study is to identify the main cause-effect relationship between human activities and the state of groundwater quality using a communication tool (the DPSIR Model; Drivers, Pressures, State, Impact and Response. A total of twenty-one samples were collected from ten peri-urban communities scattered across three conterminous Local Government Areas in Southwestern Nigeria. Each of the groundwater samples was tested for twelve parameters - total dissolved solids, pH, bicarbonate, chloride, lead, electrical conductivity, dissolved oxygen, nitrate, sulphate, magnesium and total suspended solids. The study revealed that the concentrations of DO and Pb were above threshold limits, while pH and N were just below the threshold and others elements were within acceptable limits based on Guidelines for Drinking Water Quality and Nigeria Standard for Drinking Water Quality. The study revealed that groundwater quality levels from the sampled wells are under pressure leading to reduction in the amount of freshwater availability. This is a first-order setback in achieving access to freshwater as a sustainable development goal across Less Developed Communities (LDCs globally. To combat this threat, there is the need for an integrated approach in response towards groundwater conservation and sustainability by all stakeholders.

  14. America's water: Agricultural water demands and the response of groundwater

    Science.gov (United States)

    Ho, M.; Parthasarathy, V.; Etienne, E.; Russo, T. A.; Devineni, N.; Lall, U.

    2016-07-01

    Agricultural, industrial, and urban water use in the conterminous United States (CONUS) is highly dependent on groundwater that is largely drawn from nonsurficial wells (>30 m). We use a Demand-Sensitive Drought Index to examine the impacts of agricultural water needs, driven by low precipitation, high agricultural water demand, or a combination of both, on the temporal variability of depth to groundwater across the CONUS. We characterize the relationship between changes in groundwater levels, agricultural water deficits relative to precipitation during the growing season, and winter precipitation. We find that declines in groundwater levels in the High Plains aquifer and around the Mississippi River Valley are driven by groundwater withdrawals used to supplement agricultural water demands. Reductions in agricultural water demands for crops do not, however, lead to immediate recovery of groundwater levels due to the demand for groundwater in other sectors in regions such as Utah, Maryland, and Texas.

  15. GROUNDWATER LEVEL ANALYSES OF PUNJAB, INDIA: A QUANTITATIVE APPROACH

    Directory of Open Access Journals (Sweden)

    Gopal Krishan

    2014-09-01

    Full Text Available Groundwater is considered to be the most vital for the livestock population. In Punjab, which is also the food basket of India, the groundwater level is declining at a rapid rate due to increase in the number of tube wells in the recent years and hence the groundwater abstraction has increased. In a recent study conducted for monitoring the groundwater level in Punjab, the water level data was monitored for the period 2006-2013 in Hoshiarpur, Jalandhar & Kapurthala districts of Bist-Doab; Faridkot, Firozepur, Ludhiana, Bhatinda & Patiala districts of Malwa region and Amritsar, Gurdaspur & Tarn Taran districts of Majha region of Punjab. The groundwater level data has shown that the maximum decline to the tune of 9.75 m was found in Patiala, followed by 8.57 m in Bhatinda and least decline of 3.13 m was found in Jalandhar during the period 2006-2013. The areas showing marked decline in water levels should practice artificial recharge. It is also essential to strengthen soil, water and groundwater institutions along with capacity building, training and education in specific areas like artificial recharge, groundwater modelling, watershed management, quality monitoring, and aquifer remediation on a continuous basis. Lastly, if immediate remedial measures are not taken to reverse the declining trend of water table, it would be difficult to sustain even the existing food grain production in the state, thereby, affecting the socio-economic condition of the farmers, specially the small and marginal farmers.

  16. DESIGN OF GROUNDWATER LEVEL MONITORING NETWORK WITH ORDINARY KRIGING

    Institute of Scientific and Technical Information of China (English)

    YANG Feng-guang; CAO Shu-you; LIU Xing-nian; YANG Ke-jun

    2008-01-01

    The primary network of groundwater level observation wells aims at realizing a regional groundwater management policy. It may give a regional picture of groundwater level with emphasis on the natural situation. Observation data from the primary network can be used to estimate the actual state of groundwater system. Since the cost of the installation and maintenance of a groundwater monitoring network is extremely high, the assessment of effectiveness of the network becomes very necessary. Groundwater level monitoring networks are the examples of discontinuous sampling on variables presenting spatial continuity and highly skewed frequency distributions. Anywhere in the aquifer, ordinary kriging provides estimates of the variable sampled and a standard error of the estimate. In this article, the average Kriging standard deviation was used as a criterion for the determination of network density,and the GIS-based approach was analysized. A case study of groundwater level network simulation in the Chaiwopu Basin, Xinjiang Uygur Autonomous Region, China, was presented. In the case study, the initial phreatic water observation wells were 18, a comparison of the three variogram parameters of the three defferent variogram models shows that the Gaussian model is the best. Finally, a network with 55 wells was constructed.

  17. Application of artificial neural network model for groundwater level forecasting in a river island with artificial influencing factors

    Science.gov (United States)

    Lee, Sanghoon; Yoon, Heesung; Park, Byeong-Hak; Lee, Kang-Kun

    2017-04-01

    Groundwater use has been increased for various purposes like agriculture, industry or drinking water in recent years, the issue related to sustainability on the groundwater use also has been raised. Accordingly, forecasting the groundwater level is of great importance for planning sustainable use of groundwater. In a small island surrounded by the Han River, South Korea, seasonal fluctuation of the groundwater level is characterized by multiple factors such as recharge/discharge event of the Paldang dam, Water Curtain Cultivation (WCC) during the winter season, operation of Groundwater Heat Pump System (GWHP). For a period when the dam operation is only occurred in the study area, a prediction of the groundwater level can be easily achieved by a simple cross-correlation model. However, for a period when the WCC and the GWHP systems are working together, the groundwater level prediction is challenging due to its unpredictable operation of the two systems. This study performed Artificial Neural Network (ANN) model to forecast the groundwater level in the river area reflecting the various predictable/unpredictable factors. For constructing the ANN models, two monitoring wells, YSN1 and YSO8, which are located near the injection and abstraction wells for the GWHP system were selected, respectively. By training with the groundwater level data measured in January 2015 to August 2015, response of groundwater level by each of the surface water level, the WCC and the GWHP system were evaluated. Consequentially, groundwater levels in December 2015 to March 2016 were predicted by ANN models, providing optimal fits in comparison to the observed water levels. This study suggests that the ANN model is a useful tool to forecast the groundwater level in terms of the management of groundwater. Acknowledgement : Financial support was provided by the "R&D Project on Environmental Management of Geologic CO2 Storage" from the KEITI (Project Number: 2014001810003) This research was

  18. Extent, perception and mitigation of damage due to high groundwater levels in the city of Dresden, Germany

    Science.gov (United States)

    Kreibich, H.; Thieken, A. H.; Grunenberg, H.; Ullrich, K.; Sommer, T.

    2009-07-01

    Flood risk analysis and management plans mostly neglect groundwater flooding, i.e. high groundwater levels. However, rising groundwater may cause considerable damage to buildings and infrastructure. To improve the knowledge about groundwater flooding and support risk management, a survey was undertaken in the city of Dresden (Saxony, Germany), resulting in 605 completed interviews with private households endangered by high groundwater levels. The reported relatively low flood impact and damage of groundwater floods in comparison with mixed floods was reflected by its scarce perception: Hardly anybody thinks about the risk of groundwater flooding. The interviewees thought that public authorities and not themselves, should be mainly responsible for preparedness and emergency response. Up to now, people do not include groundwater risk in their decision processes on self protection. The implementation of precautionary measures does not differ between households with groundwater or with mixed flood experience. However, less households undertake emergency measures when expecting a groundwater flood only. The state of preparedness should be further improved via an intensified risk communication about groundwater flooding by the authorities. Conditions to reach the endangered population are good, since 70% of the interviewed people are willing to inform themselves about groundwater floods. Recommendations for an improved risk communication are given.

  19. 2012 Water Levels - Mojave River and the Morongo Groundwater Basins

    Data.gov (United States)

    U.S. Geological Survey, Department of the Interior — During 2012, the U.S. Geological Survey and other agencies made approximately 2,500 water-level measurements in the Mojave River and Morongo groundwater basins....

  20. Influence of groundwater level to slope displacement by geodetic method

    Science.gov (United States)

    Sadarviana, Vera; Abidin, Hasanuddin Z.; Santoso, Djoko; Kahar, Joenil; Achmad R., T.

    2016-05-01

    In the rainy season, Indonesia often experience landslide disasters. Rainwater flows on the surface of the ground and partially into the ground, and changing the groundwater level (GWL) which can cause pressure on surrounding material. Water becomes the main factor that triggered landslides because water causes pressure force on the slopes that are prone to move. With the geometric approach, slope material displacement vectors can be known, including the origin of the material pressure using dynamic mathematical model that considers GWL. The data was used 5 campaigns of GPS observations. The results are obtained the correlation coefficients between coefficient changes in groundwater levels to the vector position as a representative of correlation between the physical and geometric parameters. There is relatively strong because of the value of the average correlation coefficient is 0.91997. Further, curves between changes in groundwater levels and the displacement position shows that the greater the groundwater levels, the greater the material position shift occurs.

  1. Comparison of GRACE data and groundwater levels for the assessment of groundwater depletion in Jordan

    Science.gov (United States)

    Liesch, Tanja; Ohmer, Marc

    2016-09-01

    Gravity Recovery and Climate Experiment (GRACE) derived groundwater storage (GWS) data are compared with in-situ groundwater levels from five groundwater basins in Jordan, using newly gridded GRACE GRCTellus land data. It is shown that (1) the time series for GRACE-derived GWS data and in-situ groundwater-level measurements can be correlated, with R 2 from 0.55 to 0.74, (2) the correlation can be widely ascribed to the seasonal and trend component, since the detrended and deseasonalized time series show no significant correlation for most cases, implying that anomalous signals that deviate from the trend or seasonal behaviour are overlaid by noise, (3) estimates for water losses in Jordan based on the trend of GRACE data from 2003 to 2013 could be up to four times higher than previously assumed using estimated recharge and abstraction rates, and (4) a significant time-lagged cross correlation of the monthly changes in GRACE-derived groundwater storage and precipitation data was found, suggesting that the conventional method for deriving GWS from GRACE data probably does not account for the typical conditions in the study basins. Furthermore, a new method for deriving plausible specific yields from GRACE data and groundwater levels is demonstrated.

  2. Groundwater management based on monitoring of land subsidence and groundwater levels in the Kanto Groundwater Basin, Central Japan

    Science.gov (United States)

    Furuno, K.; Kagawa, A.; Kazaoka, O.; Kusuda, T.; Nirei, H.

    2015-11-01

    Over 40 million people live on and exploit the groundwater resources of the Kanto Plain. The Plain encompasses metropolitan Tokyo and much of Chiba Prefecture. Useable groundwater extends to the base of the Kanto Plain, some 2500 to 3000 m below sea level. Much of the Kanto Plain surface is at sea level. By the early 1970s, with increasing urbanization and industrial expansion, local overdraft of groundwater resources caused major ground subsidence and damage to commercial and residential structures as well as to local and regional infrastructure. Parts of the lowlands around Tokyo subsided to 4.0 m below sea level; particularly affected were the suburbs of Funabashi and Gyotoku in western Chiba. In the southern Kanto Plain, regulations, mainly by local government and later by regional agencies, led to installation of about 500 monitoring wells and almost 5000 bench marks by the 1990's. Many of them are still working with new monitoring system. Long-term monitoring is important. The monitoring systems are costly, but the resulting data provide continuous measurement of the "health" of the Kanto Groundwater Basin, and thus permit sustainable use of the groundwater resource.

  3. Sea-level rise and coastal groundwater inundation and shoaling at select sites in California, USA

    Science.gov (United States)

    Hoover, Daniel J.; Odigie, Kingsley; Swarzenski, Peter W.; Barnard, Patrick

    2016-01-01

    Study regionThe study region spans coastal California, USA, and focuses on three primary sites: Arcata, Stinson Beach, and Malibu Lagoon.Study focus1 m and 2 m sea-level rise (SLR) projections were used to assess vulnerability to SLR-driven groundwater emergence and shoaling at select low-lying, coastal sites in California. Separate and combined inundation scenarios for SLR and groundwater emergence were developed using digital elevation models of study site topography and groundwater surfaces constructed from well data or published groundwater level contours.New hydrological insights for the regionSLR impacts are a serious concern in coastal California which has a long (∼1800 km) and populous coastline. Information on the possible importance of SLR-driven groundwater inundation in California is limited. In this study, the potential for SLR-driven groundwater inundation at three sites (Arcata, Stinson Beach, and Malibu Lagoon) was investigated under 1 m and 2 m SLR scenarios. These sites provide insight into the vulnerability of Northern California coastal plains, coastal developments built on beach sand or sand spits, and developed areas around coastal lagoons associated with seasonal streams and berms. Northern California coastal plains with abundant shallow groundwater likely will see significant and widespread groundwater emergence, while impacts along the much drier central and southern California coast may be less severe due to the absence of shallow groundwater in many areas. Vulnerability analysis is hampered by the lack of data on shallow coastal aquifers, which commonly are not studied because they are not suitable for domestic or agricultural use. Shallow saline aquifers may be present in many areas along coastal California, which would dramatically increase vulnerability to SLR-driven groundwater emergence and shoaling. Improved understanding of the extent and response of California coastal aquifers to SLR will help in preparing for mitigation

  4. Automated system for monitoring groundwater levels at an experimental low-level waste disposal site

    Energy Technology Data Exchange (ETDEWEB)

    Newbold, J.D.; Bogle, M.A.

    1984-06-01

    One of the major problems with disposing of low-level solid wastes in the eastern United States is the potential for water-waste interactions and leachate migration. To monitor groundwater fluctuations and the frequency with which groundwater comes into contact with a group of experimental trenches, work at Oak Ridge National Laboratory's Engineered Test Facility (ETF) has employed a network of water level recorders that feed information from 15 on-site wells to a centralized data recording system. The purpose of this report is to describe the monitoring system being used and to document the computer programs that have been developed to process the data. Included in this report are data based on more than 2 years of water level information for ETF wells 1 through 12 and more than 6 months of data from all 15 wells. The data thus reflect both long-term trends as well as a large number of short-term responses to individual storm events. The system was designed to meet the specific needs of the ETF, but the hardware and computer routines have generic application to a variety of groundwater monitoring situations. 5 references.

  5. Comparison of selection methods to deduce natural background levels for groundwater units

    NARCIS (Netherlands)

    Griffioen, J.; Passier, H.F.; Klein, J.

    2008-01-01

    Establishment of natural background levels (NBL) for groundwater is commonly performed to serve as reference when assessing the contamination status of groundwater units. We compare various selection methods to establish NBLs using groundwater quality data forfour hydrogeologically different areas i

  6. Comparison of selection methods to deduce natural background levels for groundwater units

    NARCIS (Netherlands)

    Griffioen, J.; Passier, H.F.; Klein, J.

    2008-01-01

    Establishment of natural background levels (NBL) for groundwater is commonly performed to serve as reference when assessing the contamination status of groundwater units. We compare various selection methods to establish NBLs using groundwater quality data forfour hydrogeologically different areas

  7. Risk assessment of groundwater level variability using variable Kriging methods

    Science.gov (United States)

    Spanoudaki, Katerina; Kampanis, Nikolaos A.

    2015-04-01

    Assessment of the water table level spatial variability in aquifers provides useful information regarding optimal groundwater management. This information becomes more important in basins where the water table level has fallen significantly. The spatial variability of the water table level in this work is estimated based on hydraulic head measured during the wet period of the hydrological year 2007-2008, in a sparsely monitored basin in Crete, Greece, which is of high socioeconomic and agricultural interest. Three Kriging-based methodologies are elaborated in Matlab environment to estimate the spatial variability of the water table level in the basin. The first methodology is based on the Ordinary Kriging approach, the second involves auxiliary information from a Digital Elevation Model in terms of Residual Kriging and the third methodology calculates the probability of the groundwater level to fall below a predefined minimum value that could cause significant problems in groundwater resources availability, by means of Indicator Kriging. The Box-Cox methodology is applied to normalize both the data and the residuals for improved prediction results. In addition, various classical variogram models are applied to determine the spatial dependence of the measurements. The Matérn model proves to be the optimal, which in combination with Kriging methodologies provides the most accurate cross validation estimations. Groundwater level and probability maps are constructed to examine the spatial variability of the groundwater level in the basin and the associated risk that certain locations exhibit regarding a predefined minimum value that has been set for the sustainability of the basin's groundwater resources. Acknowledgement The work presented in this paper has been funded by the Greek State Scholarships Foundation (IKY), Fellowships of Excellence for Postdoctoral Studies (Siemens Program), 'A simulation-optimization model for assessing the best practices for the

  8. Spatial modeling for groundwater arsenic levels in North Carolina.

    Science.gov (United States)

    Kim, Dohyeong; Miranda, Marie Lynn; Tootoo, Joshua; Bradley, Phil; Gelfand, Alan E

    2011-06-01

    To examine environmental and geologic determinants of arsenic in groundwater, detailed geologic data were integrated with well water arsenic concentration data and well construction data for 471 private wells in Orange County, NC, via a geographic information system. For the statistical analysis, the geologic units were simplified into four generalized categories based on rock type and interpreted mode of deposition/emplacement. The geologic transitions from rocks of a primary pyroclastic origin to rocks of volcaniclastic sedimentary origin were designated as polylines. The data were fitted to a left-censored regression model to identify key determinants of arsenic levels in groundwater. A Bayesian spatial random effects model was then developed to capture any spatial patterns in groundwater arsenic residuals into model estimation. Statistical model results indicate (1) wells close to a transition zone or fault are more likely to contain detectible arsenic; (2) welded tuffs and hydrothermal quartz bodies are associated with relatively higher groundwater arsenic concentrations and even higher for those proximal to a pluton; and (3) wells of greater depth are more likely to contain elevated arsenic. This modeling effort informs policy intervention by creating three-dimensional maps of predicted arsenic levels in groundwater for any location and depth in the area.

  9. Groundwater levels and dolomite - nuisance or necessity

    CSIR Research Space (South Africa)

    Hobbs, PJ

    2008-11-01

    Full Text Available environment enjoys particular geotechnical significance, response patterns evident in hydrographic data are looked at in terms of their reflection of natural and antropogenic stimuli. The paper concludes with a brief discussion on the legislative framework...

  10. The impact of groundwater level on soil seed bank survival

    NARCIS (Netherlands)

    Bekker, RM; Oomes, MJM; Bakker, JP

    Seed longevity of plant species is an important topic in restoration management, and little is known about the effects of environmental conditions on seed survival and longevity under natural conditions. Therefore, the effect of groundwater level on the survival of seeds in the soil seed bank of a

  11. Groundwater levels in the Kabul Basin, Afghanistan, 2004-2013

    Science.gov (United States)

    Taher, Mohammad R.; Chornack, Michael P.; Mack, Thomas J.

    2014-01-01

    The Afghanistan Geological Survey, with technical assistance from the U.S. Geological Survey, established a network of wells to measure and monitor groundwater levels to assess seasonal, areal, and potentially climatic variations in groundwater characteristics in the Kabul Basin, Afghanistan, the most populous region in the country. Groundwater levels were monitored in 71 wells in the Kabul Basin, Afghanistan, starting as early as July 2004 and continuing to the present (2013). The monitoring network is made up exclusively of existing production wells; therefore, both static and dynamic water levels were recorded. Seventy wells are in unconsolidated sediments, and one well is in bedrock. Water levels were measured periodically, generally monthly, using electric tape water-level meters. Water levels in well 64 on the grounds of the Afghanistan Geological Survey building were measured more frequently. This report provides a 10-year compilation of groundwater levels in the Kabul Basin prepared in cooperation with the Afghanistan Geological Survey. Depths to water below land surface range from a minimum of 1.47 meters (m) in the Shomali subbasin to a maximum of 73.34 m in the Central Kabul subbasin. The Logar subbasin had the smallest range in depth to water below land surface (1.5 to 12.4 m), whereas the Central Kabul subbasin had the largest range (2.64 to 73.34 m). Seasonal water-level fluctuations can be estimated from the hydrographs in this report for wells that have depth-to-water measurements collected under static conditions. The seasonal water-level fluctuations range from less than 1 m to a little more than 7 m during the monitoring period. In general, the hydrographs for the Deh Sabz, Logar, Paghman and Upper Kabul, and Shomali subbasins show relatively little change in the water-level trend during the period of record, whereas hydrographs for the Central Kabul subbasin show water level decreases of several meters to about 25 m.

  12. Groundwater Level Status Report for Fiscal Year 2007 - Los Alamos National Laboratory

    Energy Technology Data Exchange (ETDEWEB)

    Shannon P. Allen, Richard J. Koch

    2008-03-17

    The status of groundwater level monitoring at Los Alamos National Laboratory in Fiscal Year 2007 is provided in this report. The Groundwater Level Monitoring Project was instituted in 2005 to provide a framework for the collection and processing of quality controlled groundwater level data. This report summarizes groundwater level data for 166 monitoring wells, including 45 regional aquifer wells, 25 intermediate wells, and 96 alluvial wells, and 11 water supply wells. Pressure transducers were installed in 133 monitoring wells for continuous monitoring of groundwater levels. Time-series hydrographs of groundwater level data are presented along with pertinent construction and location information for each well.

  13. Groundwater Level Status Report for Fiscal Year 2006 Los Alamos National Laboratory

    Energy Technology Data Exchange (ETDEWEB)

    Shannon P. Allen, Richard J. Koch

    2007-03-30

    The status of groundwater level monitoring at Los Alamos National Laboratory in Fiscal Year 2006 is provided in this report. The Groundwater Level Monitoring Project was instituted in 2005 for providing a framework for the collection and processing of quality controlled groundwater level data. This report summarizes groundwater level data for 158 monitoring wells, including 43 regional aquifer wells, 23 intermediate wells, and 92 alluvial wells. Pressure transducers were installed in 132 monitoring wells for continuous monitoring of groundwater levels. Time-series hydrographs of groundwater level data are presented along with pertinent construction and location information for each well.

  14. Depletion and response of deep groundwater to climate-induced pumping variability

    Science.gov (United States)

    Russo, Tess A.; Lall, Upmanu

    2017-01-01

    Groundwater constitutes a critical component of our water resources. Widespread groundwater level declines have occurred in the USA over recent decades, including in regions not typically considered water stressed, such as areas of the Northwest and mid-Atlantic Coast. This loss of water storage reflects extraction rates that exceed natural recharge and capture. Here, we explore recent changes in the groundwater levels of deep aquifers from wells across the USA, and their relation to indices of interannual to decadal climate variability and to annual precipitation. We show that groundwater level changes correspond to selected global climate variations. Although climate-induced variations of deep aquifer natural recharge are expected to have multi-year time lags, we find that deep groundwater levels respond to climate over timescales of less than one year. In irrigated areas, the annual response to local precipitation in the deepest wells may reflect climate-induced pumping variability. An understanding of how the human response to drought through pumping leads to deep groundwater changes is critical to manage the impacts of interannual to decadal and longer climate variability on the nation’s water resources.

  15. Groundwater.

    Science.gov (United States)

    Braids, Olin C.; Gillies, Nola P.

    1978-01-01

    Presents a literature review of groundwater quality covering publications of 1977. This review includes: (1) sources of groundwater contamination; and (2) management of groundwater. A list of 59 references is also presented. (HM)

  16. Simulation of the effects of rainfall and groundwater use on historical lake water levels, groundwater levels, and spring flows in central Florida

    Science.gov (United States)

    O'Reilly, Andrew M.; Roehl, Edwin A.; Conrads, Paul A.; Daamen, Ruby C.; Petkewich, Matthew D.

    2014-01-01

    The urbanization of central Florida has progressed substantially in recent decades, and the total population in Lake, Orange, Osceola, Polk, and Seminole Counties more than quadrupled from 1960 to 2010. The Floridan aquifer system is the primary source of water for potable, industrial, and agricultural purposes in central Florida. Despite increases in groundwater withdrawals to meet the demand of population growth, recharge derived by infiltration of rainfall in the well-drained karst terrain of central Florida is the largest component of the long-term water balance of the Floridan aquifer system. To complement existing physics-based groundwater flow models, artificial neural networks and other data-mining techniques were used to simulate historical lake water level, groundwater level, and spring flow at sites throughout the area. Historical data were examined using descriptive statistics, cluster analysis, and other exploratory analysis techniques to assess their suitability for more intensive data-mining analysis. Linear trend analyses of meteorological data collected by the National Oceanic and Atmospheric Administration at 21 sites indicate 67 percent of sites exhibited upward trends in air temperature over at least a 45-year period of record, whereas 76 percent exhibited downward trends in rainfall over at least a 95-year period of record. Likewise, linear trend analyses of hydrologic response data, which have varied periods of record ranging in length from 10 to 79 years, indicate that water levels in lakes (307 sites) were about evenly split between upward and downward trends, whereas water levels in 69 percent of wells (out of 455 sites) and flows in 68 percent of springs (out of 19 sites) exhibited downward trends. Total groundwater use in the study area increased from about 250 million gallons per day (Mgal/d) in 1958 to about 590 Mgal/d in 1980 and remained relatively stable from 1981 to 2008, with a minimum of 559 Mgal/d in 1994 and a maximum of 773

  17. Effects of sea-level rise on barrier island groundwater system dynamics: ecohydrological implications

    Science.gov (United States)

    Masterson, John P.; Fienen, Michael N.; Thieler, E. Robert; Gesch, Dean B.; Gutierrez, Benjamin T.; Plant, Nathaniel G.

    2014-01-01

    We used a numerical model to investigate how a barrier island groundwater system responds to increases of up to 60 cm in sea level. We found that a sea-level rise of 20 cm leads to substantial changes in the depth of the water table and the extent and depth of saltwater intrusion, which are key determinants in the establishment, distribution and succession of vegetation assemblages and habitat suitability in barrier islands ecosystems. In our simulations, increases in water-table height in areas with a shallow depth to water (or thin vadose zone) resulted in extensive groundwater inundation of land surface and a thinning of the underlying freshwater lens. We demonstrated the interdependence of the groundwater response to island morphology by evaluating changes at three sites. This interdependence can have a profound effect on ecosystem composition in these fragile coastal landscapes under long-term changing climatic conditions.

  18. Measuring and modeling spatio-temporal patterns of groundwater storage dynamics to better understand nonlinear streamflow response

    Science.gov (United States)

    Rinderer, Michael; van Meerveld, Ilja; McGlynn, Brian

    2017-04-01

    Information about the spatial and temporal variability in catchment scale groundwater storage is needed to identify runoff source area dynamics and better understand variability in streamflow. However, information on groundwater levels is typically only available at a limited number of monitoring sites and interpolation or upscaling is necessary to obtain information on catchment scale groundwater dynamics. Here we used data from 51 spatially distributed groundwater monitoring sites in a Swiss pre-alpine catchment and time series clustering to define six groundwater response clusters. Each of the clusters was distinct in terms of the groundwater rise and recession but also had distinctly different topographic site characteristics, which allowed us to assign a groundwater response cluster to all non-monitored locations. Each of them was then assigned the mean groundwater response of the monitored cluster members. A site was considered active (i.e., enabling lateral subsurface flow) when the groundwater levels rose above the groundwater response threshold which was defined based on the depth of the more transmissive soil layers (typically between 10 cm and 30 cm below the soil surface). This allowed us to create maps of the active areas across the catchment at 15 min time intervals. The mean fraction of agreement between modeled groundwater activation (based on the mean cluster member time series) and measured groundwater activation (based on the measured groundwater level time series at a monitoring site) was 0.91 (25th percentile: 0.88, median: 0.92, 75th percentile: 0.95). The fraction of agreement dropped by 10 to 15 % at the beginning of events but was never lower than 0.4. Connectivity between all active areas and the stream network was determined using a graph theory approach. During rainfall events, the simulated active and connected area extended mainly laterally and longitudinally along the channel network, which is in agreement with the variable source

  19. Preliminary investigation of the effects of sea-level rise on groundwater levels in New Haven, Connecticut

    Science.gov (United States)

    Bjerklie, David M.; Mullaney, John R.; Stone, Janet R.; Skinner, Brian J.; Ramlow, Matthew A.

    2012-01-01

    Global sea level rose about 0.56 feet (ft) (170 millimeters (mm)) during the 20th century. Since the 1960s, sea level has risen at Bridgeport, Connecticut, about 0.38 ft (115 mm), at a rate of 0.008 ft (2.56 mm + or - 0.58 mm) per year. With regional subsidence, and with predicted global climate change, sea level is expected to continue to rise along the northeast coast of the United States through the 21st century. Increasing sea levels will cause groundwater levels in coastal areas to rise in order to adjust to the new conditions. Some regional climate models predict wetter climate in the northeastern United States under some scenarios. Scenarios for the resulting higher groundwater levels have the potential to inundate underground infrastructure in lowlying coastal cities. New Haven is a coastal city in Connecticut surrounded and bisected by tidally affected waters. Monitoring of water levels in wells in New Haven from August 2009 to July 2010 indicates the complex effects of urban influence on groundwater levels. The response of groundwater levels to recharge and season varied considerably from well to well. Groundwater temperatures varied seasonally, but were warmer than what was typical for Connecticut, and they seem to reflect the influence of the urban setting, including the effects of conduits for underground utilities. Specific conductance was elevated in many of the wells, indicating the influence of urban activities or seawater in Long Island Sound. A preliminary steady-state model of groundwater flow for part of New Haven was constructed using MODFLOW to simulate current groundwater levels (2009-2010) and future groundwater levels based on scenarios with a rise of 3 ft (0.91 meters (m)) in sea level, which is predicted for the end of the 21st century. An additional simulation was run assuming a 3-ft rise in sea level combined with a 12-percent increase in groundwater recharge. The model was constructed from existing hydrogeologic information for the

  20. Remediation alternatives for low-level herbicide contaminated groundwater

    Energy Technology Data Exchange (ETDEWEB)

    Conger, R.M. [BASF Corp., Geismar, LA (United States)

    1995-10-01

    In early 1995, an evaluation of alternatives for remediation of a shallow groundwater plume containing low-levels of an organic herbicide was conducted at BASF Corporation, a petrochemical facility located in Ascension Parish, Louisiana. The contaminated site is located on an undeveloped portion of property within 1/4 mile of the east bank of the Mississippi River near the community of Geismar. Environmental assessment data indicated that about two acres of the thirty acre site had been contaminated from past waste management practices with the herbicide bentazon. Shallow soils and groundwater between 5 to 15 feet in depth were affected. Maximum concentrations of bentazon in groundwater were less than seven parts per million. To identify potentially feasible remediation alternatives, the environmental assessment data, available research, and cost effectiveness were reviewed. After consideration of a preliminary list of alternatives, only two potentially feasible alternatives could be identified. Groundwater pumping, the most commonly used remediation alternative, followed by carbon adsorption treatment was identified as was a new innovative alternative known as vegetative transpiration. This alternative relies on the natural transpiration processes of vegetation to bioremediate organic contaminants. Advantages identified during screening suggest that the transpiration method could be the best remediation alternative to address both economic and environmental factors. An experiment to test critical factors of the vegetatived transpiration alternative with bentazon was recommended before a final decision on feasibility can be made.

  1. Analysis of 1997–2008 groundwater level changes in the upper Deschutes Basin, Central Oregon

    Science.gov (United States)

    Gannett, Marshall W.; Lite, Kenneth E.

    2013-01-01

    from on-farm losses over the past decade were relatively small, approaching an estimated 1,000 acre-feet per year by the late 2000s. All these changes in the hydrologic budget contributed to declines in groundwater levels. Groundwater flow model simulations indicate that climate variations have the largest influence on groundwater levels throughout the upper Deschutes Basin, and that impacts from pumping and canal lining also contribute but are largely restricted to the central part of the basin that extends north from near Benham Falls to Lower Bridge, and east from Sisters to the community of Powell Butte. Outside of this central area, the water-level response from changes in pumping and irrigation canal leakage cannot be discerned from the larger response to climate-driven changes in recharge. Within this central area, where measured water-level declines have generally ranged from about 5 to 14 feet since the mid-1990s, climate variations are still the dominant factor influencing groundwater levels, accounting for approximately 60–70 percent of the measured declines. Post-1994 increases in groundwater pumping account for about 20–30 percent of the measured declines in the central part of the basin, depending on location, and decreases in recharge due to canal lining account for about 10 percent of the measured declines. Decreases in recharge from on-farm losses were simulated, but the effects were negligible compared to climate influences, groundwater pumping, and the effects of canal lining and piping. Observation well data and model simulation results indicate that water levels in the Cascade Range rose and declined tens of feet in response to wet and dry climate cycles over the past two decades. Water levels in the central part of the basin, in contrast, steadily declined during the same period, with the rate of decline lessening during wet periods. This difference is because the water-level response from recharge is damped as water moves (diffuses) from the

  2. Separation of base flow from streamflow using groundwater levels - illustrated for the Pang catchment (UK)

    NARCIS (Netherlands)

    Peters, E.; Lanen, van H.A.J.

    2005-01-01

    A new filter to separate base flow from streamflow has developed that uses observed groundwater levels. To relate the base flow to the observed groundwater levels, a non-linear relation was used. This relation is suitable for unconfined aquifers with deep groundwater levels that do not respond to

  3. Separation of base flow from streamflow using groundwater levels - illustrated for the Pang catchment (UK)

    NARCIS (Netherlands)

    Peters, E.; Lanen, van H.A.J.

    2005-01-01

    A new filter to separate base flow from streamflow has developed that uses observed groundwater levels. To relate the base flow to the observed groundwater levels, a non-linear relation was used. This relation is suitable for unconfined aquifers with deep groundwater levels that do not respond to in

  4. Using Independent Components Analysis to diminish the response of groundwater in borehole strainmeter

    Science.gov (United States)

    Chen, Chih-Yen; Hu, Jyr-Ching

    2017-04-01

    With designed feather, borehole strainmeter can not only record minor signals of tectonic movements, but also broad environmental signs such as barometry, rainfall and groundwater. Among these external factor, groundwater will influence the observation of borehole strainmeter mostly. According to essential observation, groundwater will cause much bigger response than the target tectonic strain change. We use co-sited piezometer to record pore pressure of groundwater in the rock formation in order to obtain the relationship of stain change and pore pressure. But there still exist some puzzle that can not be solved. First, due to instrument limitation, we could not set the pore pressure transducer in the same aquifer as strainmeter did. In this case, the response due to pore pressure change might be not fully correct. Furthermore, through pore-pressure transducers were set in most observatory, problem of electricity and connectivity will cause the record lack and lost. Therefore, it is necessary to find out a better and more stable method to diminish the groundwater response of strainmeter data.Strain transducer with different orientation can observe the groundwater response in different scale. If we can extract out groundwater signal from each independent strain transducer and estimate its original source. That will significantly rise signal strength and lower noise level. The case belongs some kind of blind-signal-separation (BSS) problem. The procedure of BSS extract or rebuild signal that can't be observed directly in many mixed sources and Independent-Component-Analysis (ICA) is one method adopted broadly. ICA is an analysis to find out parts which have statistics independence and non-Gaussian factor in complex signals. We use FastICA developed by to figure out the groundwater response strain in original strain data, and try to diminish it to rise the signal strength. We preceded strain data previously, then using ICA to separate data into serval independent

  5. Forecasting the probability of future groundwater levels declining below specified low thresholds in the conterminous U.S.

    Science.gov (United States)

    Dudley, Robert W.; Hodgkins, Glenn A.; Dickinson, Jesse

    2017-01-01

    We present a logistic regression approach for forecasting the probability of future groundwater levels declining or maintaining below specific groundwater-level thresholds. We tested our approach on 102 groundwater wells in different climatic regions and aquifers of the United States that are part of the U.S. Geological Survey Groundwater Climate Response Network. We evaluated the importance of current groundwater levels, precipitation, streamflow, seasonal variability, Palmer Drought Severity Index, and atmosphere/ocean indices for developing the logistic regression equations. Several diagnostics of model fit were used to evaluate the regression equations, including testing of autocorrelation of residuals, goodness-of-fit metrics, and bootstrap validation testing. The probabilistic predictions were most successful at wells with high persistence (low month-to-month variability) in their groundwater records and at wells where the groundwater level remained below the defined low threshold for sustained periods (generally three months or longer). The model fit was weakest at wells with strong seasonal variability in levels and with shorter duration low-threshold events. We identified challenges in deriving probabilistic-forecasting models and possible approaches for addressing those challenges.

  6. Groundwater recharge and time lag measurement through Vertosols using impulse response functions

    Science.gov (United States)

    Hocking, Mark; Kelly, Bryce F. J.

    2016-04-01

    Throughout the world there are many stressed aquifers used to support irrigated agriculture. The Condamine River catchment (southern Queensland, Australia) is one example of a globally significant agricultural region where groundwater use has exceeded recharge over the last 50 years. There is a high dependence on groundwater in this catchment, because yearly rainfall is highly variable, and actual evapotranspiration often exceeds rainfall. To better manage the aquifer there is a need to correctly conceptualise the primary inputs and outputs of the system, and characterise the lags in system response to all forcings. In catchment models it is particularly important to correctly proportion diffuse (areal) rainfall recharge and to account for the lag between rainfall and recharge at the water table. Throughout large portions of the Condamine Catchment, groundwater levels are now 20 or more metres below the ground surface. This study aimed to better quantify the lag between rainfall and recharge at the water table using the predefined impulse response function in continuous time method (PIRFICT; von Asmuth et al., 2002; von Asmuth, 2012). The PIRFICT method was applied to 255 multi-decadal groundwater level data sets throughout the catchment. Inputs into the modelling include rainfall, irrigation deep drainage, stream water level, evapotranspiration, and groundwater extractions. As an independent check the PIRFICT model derived diffuse recharge estimates are compared to point lysimeter and geochemical recharge estimates in the Vertosol soils within this catchment. It is estimated using the PIRFICT method that in the Condamine Catchment between 1990 and 2012, the mean rain-derived groundwater recharge is 4.4 mm/year. Mean groundwater response from rainfall was determined to be 5.3 years: range 188 days to 48 years. The recharge estimates are consistent with both geochemical and lysimeter point measurements of recharge. It is concluded that where extensive groundwater

  7. Response of Groundwater to Climate Change under Extreme Climate Conditions in North China Plain

    Institute of Scientific and Technical Information of China (English)

    Ying Zhang; Jincui Wang; Jihong Jing; Jichao Sun

    2014-01-01

    The North China Plain (NCP) is one of the water shortage areas of China. Lack of water resources restricted the economic and social development of North China area and resulted in deterio-ration of ecosystem and natural environment. Influenced by the climate change and human activities, the water circulation of NCP was largely changed and the crisis of water resources was aggravated. Therefore, it is important to study the features of the extreme climate and the response mechanism of groundwater to climate change. We analyzed the trend of climate change and extreme climate features in the past 60 years based on the monitoring data of meteorological stations. And then the response characteristics of groundwater to climate change were discussed. The average temperature of NCP was in an obviously upward trend. The overall precipitation variation was in a downward trend. The cli-mate change in this area showed a warming-drying trend. The intensity of extreme precipitation dis-played a trend of declining and then increasing from north to south as well as declining from eastern coastal plain to the piedmont plain. Grey correlation degree analysis indicated that groundwater depth had a close relationship with precipitation and human activities in NCP. The response of groundwater level to precipitation differed from the piedmont alluvial-pluvial plain to the coastal plain. The response was more obvious in the coastal plain than the piedmont alluvial-pluvial plain and the middle plain. The precipitation influenced the groundwater depth both directly and indirectly. Under the condition of extreme precipitation, the impact would aggravate, in the forms of rapid or lag raise of groundwater levels.

  8. Groundwater-dependent ecosystems: recent insights, new techniques and an ecosystem-scale threshold response

    Directory of Open Access Journals (Sweden)

    D. Eamus

    2015-05-01

    Full Text Available Groundwater-dependent ecosystems (GDEs are at risk globally due to unsustainable levels of groundwater extraction, especially in arid and semi-arid regions. In this review, we examine recent developments in the ecohydrology of GDEs with a focus on three knowledge gaps: (1 how do we locate GDEs, (2 how much water is transpired from shallow aquifers by GDEs; and (3 what are the responses of GDEs to excessive groundwater extraction? The answers to these questions will determine water allocations that are required to sustain functioning of GDEs and to guide regulations on groundwater extraction to avoid negative impacts on GDEs. We discuss three methods for identifying GDEs: (1 fluctuations in depth-to-groundwater that are associated with diurnal variations in transpiration, (2 stable isotope analysis of water sources in the transpiration stream; and (3 remote sensing methods. We then discuss several methods for estimating rates of GW use, including direct measurement using sapflux or eddy covariance technologies, estimation of a climate wetness index within a Budyko framework, spatial distribution of ET using remote sensing, groundwater modelling and stable isotopes. Remote sensing methods often rely on direct measurements to calibrate the relationship between vegetation indices and ET. ET from GDEs is also determined using hydrologic models of varying complexity, from the "White method" to fully coupled, variable saturation models. Combinations of methods are typically employed to obtain clearer insight into the components of groundwater discharge in GDEs, such as the proportional importance of transpiration vs. evaporation (e.g., using stable isotopes or from groundwater vs. rainwater sources. Groundwater extraction can have severe consequences on structure and function of GDEs. In the most extreme cases, phreatophytes experience crown dieback and death following groundwater drawdown. We provide a brief review of two case studies of the impacts

  9. Reliable groundwater levels: failures and lessons learned from modeling and monitoring studies

    Science.gov (United States)

    Van Lanen, Henny A. J.

    2017-04-01

    Adequate management of groundwater resources requires an a priori assessment of impacts of intended groundwater abstractions. Usually, groundwater flow modeling is used to simulate the influence of the planned abstraction on groundwater levels. Model performance is tested by using observed groundwater levels. Where a multi-aquifer system occurs, groundwater levels in the different aquifers have to be monitored through observation wells with filters at different depths, i.e. above the impermeable clay layer (phreatic water level) and beneath (artesian aquifer level). A reliable artesian level can only be measured if the space between the outer wall of the borehole (vertical narrow shaft) and the observation well is refilled with impermeable material at the correct depth (post-drilling phase) to prevent a vertical hydraulic connection between the artesian and phreatic aquifer. We were involved in improper refilling, which led to impossibility to monitor reliable artesian aquifer levels. At the location of the artesian observation well, a freely overflowing spring was seen, which implied water leakage from the artesian aquifer affected the artesian groundwater level. Careful checking of the monitoring sites in a study area is a prerequisite to use observations for model performance assessment. After model testing the groundwater model is forced with proposed groundwater abstractions (sites, extraction rates). The abstracted groundwater volume is compensated by a reduction of groundwater flow to the drainage network and the model simulates associated groundwater tables. The drawdown of groundwater level is calculated by comparing the simulated groundwater level with and without groundwater abstraction. In lowland areas, such as vast areas of the Netherlands, the groundwater model has to consider a variable drainage network, which means that small streams only carry water during the wet winter season, and run dry during the summer. The main streams drain groundwater

  10. Potential effects of existing and proposed groundwater withdrawals on water levels and natural groundwater discharge in Snake Valley and surrounding areas, Utah and Nevada

    Science.gov (United States)

    Masbruch, Melissa D.; Brooks, Lynette E.

    2017-04-14

    Several U.S. Department of Interior (DOI) agencies are concerned about the cumulative effects of groundwater development on groundwater resources managed by, and other groundwater resources of interest to, these agencies in Snake Valley and surrounding areas. The new water uses that potentially concern the DOI agencies include 12 water-right applications filed in 2005, totaling approximately 8,864 acre-feet per year. To date, only one of these applications has been approved and partially developed. In addition, the DOI agencies are interested in the potential effects of three new water-right applications (UT 18-756, UT 18-758, and UT 18-759) and one water-right change application (UT a40687), which were the subject of a water-right hearing on April 19, 2016.This report presents a hydrogeologic analysis of areas in and around Snake Valley to assess potential effects of existing and future groundwater development on groundwater resources, specifically groundwater discharge sites, of interest to the DOI agencies. A previously developed steady-state numerical groundwater-flow model was modified to transient conditions with respect to well withdrawals and used to quantify drawdown and capture (withdrawals that result in depletion) of natural discharge from existing and proposed groundwater withdrawals. The original steady-state model simulates and was calibrated to 2009 conditions. To investigate the potential effects of existing and proposed groundwater withdrawals on the groundwater resources of interest to the DOI agencies, 10 withdrawal scenarios were simulated. All scenarios were simulated for periods of 5, 10, 15, 30, 55, and 105 years from the start of 2010; additionally, all scenarios were simulated to a new steady state to determine the ultimate long-term effects of the withdrawals. Capture maps were also constructed as part of this analysis. The simulations used to develop the capture maps test the response of the system, specifically the reduction of natural

  11. A method to improve the stability and accuracy of ANN- and SVM-based time series models for long-term groundwater level predictions

    Science.gov (United States)

    Yoon, Heesung; Hyun, Yunjung; Ha, Kyoochul; Lee, Kang-Kun; Kim, Gyoo-Bum

    2016-05-01

    The prediction of long-term groundwater level fluctuations is necessary to effectively manage groundwater resources and to assess the effects of changes in rainfall patterns on groundwater resources. In the present study, a weighted error function approach was utilised to improve the performance of artificial neural network (ANN)- and support vector machine (SVM)-based recursive prediction models for the long-term prediction of groundwater levels in response to rainfall. The developed time series models were applied to groundwater level data from 5 groundwater-monitoring stations in South Korea. The results demonstrated that the weighted error function approach can improve the stability and accuracy of recursive prediction models, especially for ANN models. The comparison of the model performance showed that the recursive prediction performance of the SVM was superior to the performance of the ANN in this case study.

  12. Groundwater level deterioration issues and suggested solution for the water curtain cultivation area in South Korea

    Science.gov (United States)

    Kim, Yongcheol; Lee, Bongju; Ha, Kucheol; Yoon, Yunyeol; Moon, Sangho; Cho, Suyoung; Kim, Seongyun

    2013-04-01

    Protected water curtain cultivation system is an energy saving technique for winter season by splashing groundwater on the inner roof of the green house. But the issue is that the method results in groundwater level deterioration because it disposes the used groundwater to nearby stream. Reuse of the groundwater for water curtain cultivation is important Groundwater level, steam level, and groundwater usage rate are investigated at the five green house concentrated areas such as Cheongwon, Namyangju, Choongju, Namwon, Jinju. Groundwater usage rate is estimated using a ultrasonic flowmeter for a specific well and using the combination of pressure sensor and propeller type velocity counting equipment at a water disposal channel from November to April which is water curtain cultivating season. Groundwater usage rate ranges from 46.9m3/d to 108.0m3/d for a 10a greenhouse. Groundwater level change is strongly influenced by seasonal variation of rainfall and concentrated pumping activities in winter but the level is lower than stream level all year long resulting in all year around losing stream at Cheongwon, Namyangju, Jinju. At Nanwon, the stream is converted from losing one in winter to gaining one in summer. Groundwater level deterioration at concentrated water curtain cultivation area is found to be severe for some area where circulating water curtain cultivation system is need to be applied for groundwater restoration and sustainable cultivation in winter. Circulating water curtain cultivation system can restore the groundwater level by recharging the used groundwater through injection well and then pumping out from pumping well.

  13. Impacts of Future Climate Change and Baltic Sea Level Rise on Groundwater Recharge, Groundwater Levels, and Surface Leakage in the Hanko Aquifer in Southern Finland

    Directory of Open Access Journals (Sweden)

    Samrit Luoma

    2014-11-01

    Full Text Available The impact of climate change and Baltic Sea level rise on groundwater resources in a shallow, unconfined, low-lying coastal aquifer in Hanko, southern Finland, was assessed using the UZF1 model package coupled with the three-dimensional groundwater flow model MODFLOW to simulate flow from the unsaturated zone through the aquifer. The snow and PET models were used to calculate the surface water availability for infiltration from the precipitation data used in UZF1. Infiltration rate, flow in the unsaturated zone and groundwater recharge were then simulated using UZF1. The simulation data from climate and sea level rise scenarios were compared with present data. The results indicated changes in recharge pattern during 2071–2100, with recharge occurring earlier in winter and early spring. The seasonal impacts of climate change on groundwater recharge were more significant, with surface overflow resulting in flooding during winter and early spring and drought during summer. Rising sea level would cause some parts of the aquifer to be under sea level, compromising groundwater quality due to intrusion of sea water. This, together with increased groundwater recharge, would raise groundwater levels and consequently contribute more surface leakage and potential flooding in the low-lying aquifer.

  14. Spatial analyses of groundwater levels using universal kriging

    Indian Academy of Sciences (India)

    Kemal Sulhi Gundogdu; Ibrahim Guney

    2007-02-01

    For water levels, generally a non-stationary variable, the technique of universal kriging is applied in preference to ordinary kriging as the interpolation method. Each set of data in every sector can fit different empirical semivariogram models since they have different spatial structures. These models can be classified as circular, spherical, tetraspherical, pentaspherical, exponential, gaussian, rational quadratic, hole effect, K-bessel, J-bessel and stable. This study aims to determine which of these empirical semivariogram models will be best matched with the experimental models obtained from groundwater-table values collected from Mustafakemalpasa left bank irrigation scheme in 2002. The model having the least error was selected by comparing the observed water-table values with the values predicted by empirical semivariogram models. It was determined that the rational quadratic empirical semivariogram model is the best fitted model for the studied irrigation area.

  15. Microbial Community-Level Physiological Profiles (CLPP) and herbicide mineralization potential in groundwater affected by agricultural land use

    DEFF Research Database (Denmark)

    Janniche, Gry Sander; Spliid, Henrik; Albrechtsen, Hans-Jørgen

    2012-01-01

    Diffuse groundwater pollution from agricultural land use may impact the microbial groundwater community, which was investigated as Community-Level Physiological Profiles (CLPP) using EcoPlate™. Water was sampled from seven piezometers and a spring in a small agricultural catchment with diffuse...... herbicide and nitrate pollution. Based on the Shannon–Wiener and Simpson's diversity indices the diversity in the microbial communities was high. The response from the EcoPlates™ showed which substrates support groundwater bacteria, and all 31 carbon sources were utilized by organisms from at least one......-galacturonic acid, tween 40, and 4-hydroxy benzoic acid as substrates, whereas none preferred 2-hydroxy benzoic acid, α-d-lactose, d,l-α-glycerol phosphate, α-ketobutyric acid, l-threonine and glycyl-l-glutamic acid. Principal Component Analysis of the CLPP's clustered the most agriculturally affected groundwater...

  16. Confirmation of elevated arsenic levels in groundwater of Myanmar

    Science.gov (United States)

    van Geen, Alexander; Win, Kyi Htut; Zaw, Than; Naing, Win; Mey, Jacob L.; Mailloux, Brian

    2014-01-01

    Millions of villagers across South and Southeast Asia are exposed to toxic levels of arsenic (As) by drinking well water. In order to confirm field-kit results that Myanmar is also affected, a total of 55 wells were tested in the field in January 2013 and sampled for laboratory analysis across seven villages spanning a range of As contamination in the lower Ayeyarwady basin. Elevated concentrations of As (50–630 μg/L) were measured in wells up to 60 m deep and associated with high levels of Fe (up to 21 mg/L) and low concentrations of SO4 (<0.05 mg/L). Concentrations of As <10 μg/L were measured in some shallow (<30 m) grey sands and in both shallow and deep orange sands. These results indicate that the main mechanism of As release to groundwater in Myanmar is the reductive dissolution of Fe oxyhydroxides, as in the neighboring Bengal, Mekong, and Red River basins. Concentrations of As in groundwater of Myanmar are therefore unlikely to change rapidly over time and switching to existing low-As wells is a viable way of reducing exposure in the short term. However, only 17 of the 55 well owners interviewed correctly recalled the status of their well despite extensive testing in the region. A renewed effort is thus needed to test existing wells and new wells that continue to be installed and to communicate the health risks of exposure to As for infants, children, and adults. PMID:24530581

  17. Phreatophytic vegetation and groundwater fluctuations: a review of current research and application of ecosystem response modeling with an emphasis on great basin vegetation.

    Science.gov (United States)

    Naumburg, Elke; Mata-Gonzalez, Ricardo; Hunter, Rachael G; McLendon, Terry; Martin, David W

    2005-06-01

    Although changes in depth to groundwater occur naturally, anthropogenic alterations may exacerbate these fluctuations and, thus, affect vegetation reliant on groundwater. These effects include changes in physiology, structure, and community dynamics, particularly in arid regions where groundwater can be an important water source for many plants. To properly manage ecosystems subject to changes in depth to groundwater, plant responses to both rising and falling groundwater tables must be understood. However, most research has focused exclusively on riparian ecosystems, ignoring regions where groundwater is available to a wider range of species. Here, we review responses of riparian and other species to changes in groundwater levels in arid environments. Although decreasing water tables often result in plant water stress and reduced live biomass, the converse is not necessarily true for rising water tables. Initially, rising water tables kill flooded roots because most species cannot tolerate the associated low oxygen levels. Thus, flooded plants can also experience water stress. Ultimately, individual species responses to either scenario depend on drought and flooding tolerance and the change in root system size and water uptake capacity. However, additional environmental and biological factors can play important roles in the severity of vegetation response to altered groundwater tables. Using the reviewed information, we created two conceptual models to highlight vegetation dynamics in areas with groundwater fluctuations. These models use flow charts to identify key vegetation and ecosystem properties and their responses to changes in groundwater tables to predict community responses. We then incorporated key concepts from these models into EDYS, a comprehensive ecosystem model, to highlight the potential complexity of predicting community change under different fluctuating groundwater scenarios. Such models provide a valuable tool for managing vegetation and

  18. Groundwater response to changing water-use practices in sloping aquifers using convolution of transient response functions

    Science.gov (United States)

    An integrated foundation is presented to study the impacts of external forcings on irrigated agricultural systems. Individually, models are presented that simulate groundwater hydrogeology and econometric farm level crop choices and irrigated water use. The natural association between groundwater we...

  19. Characterizing the spatiotemporal variability of groundwater levels of alluvial aquifers in different settings using drought indices

    Science.gov (United States)

    Haas, Johannes Christoph; Birk, Steffen

    2017-05-01

    snow as compared with those with much snow. This is in agreement with typical aquifer response times over 1 month, suggesting that short events such as floods will not affect much of the aquifer, whereas a long-term event such as a drought or snow-rich winter will. Splitting the time series into periods of 12 years reveals a tendency towards higher correlations in the most recent time period from 1999 to 2010. This time period also shows the highest number of events with SPI values below -2. The SGI values behave in a similar way only in the foreland aquifer, whereas the investigated Alpine aquifers exhibit a contrasting behavior with the highest number of low SGI events in the time before 1986. This is a result of overlying trends and suggests that the groundwater levels within these subregions are more strongly influenced by direct human impacts, e.g., on the river, than by changes in precipitation. Thus, direct human impacts must not be ignored when assessing climate change impacts on alluvial aquifers situated in populated valleys.

  20. Efficient Calibration of Computationally Intensive Groundwater Models through Surrogate Modelling with Lower Levels of Fidelity

    Science.gov (United States)

    Razavi, S.; Anderson, D.; Martin, P.; MacMillan, G.; Tolson, B.; Gabriel, C.; Zhang, B.

    2012-12-01

    Many sophisticated groundwater models tend to be computationally intensive as they rigorously represent detailed scientific knowledge about the groundwater systems. Calibration (model inversion), which is a vital step of groundwater model development, can require hundreds or thousands of model evaluations (runs) for different sets of parameters and as such demand prohibitively large computational time and resources. One common strategy to circumvent this computational burden is surrogate modelling which is concerned with developing and utilizing fast-to-run surrogates of the original computationally intensive models (also called fine models). Surrogates can be either based on statistical and data-driven models such as kriging and neural networks or simplified physically-based models with lower fidelity to the original system (also called coarse models). Fidelity in this context refers to the degree of the realism of a simulation model. This research initially investigates different strategies for developing lower-fidelity surrogates of a fine groundwater model and their combinations. These strategies include coarsening the fine model, relaxing the numerical convergence criteria, and simplifying the model geological conceptualisation. Trade-offs between model efficiency and fidelity (accuracy) are of special interest. A methodological framework is developed for coordinating the original fine model with its lower-fidelity surrogates with the objective of efficiently calibrating the parameters of the original model. This framework is capable of mapping the original model parameters to the corresponding surrogate model parameters and also mapping the surrogate model response for the given parameters to the original model response. This framework is general in that it can be used with different optimization and/or uncertainty analysis techniques available for groundwater model calibration and parameter/predictive uncertainty assessment. A real-world computationally

  1. The Resilience of Groundwater Remediation System in Response to Changing Conditions

    Science.gov (United States)

    Hou, D.

    2016-12-01

    Anthropogenic activities have caused the contamination of groundwater resources at many locations. In an effort to protect human health and prevent further spreading of groundwater contamination, remediation systems have been or will be built at hundreds of thousands of sites. While the short term effectiveness has been the focus of past research and practice, the long-term effectiveness is increasingly scrutinized. When assessing the long-term effectiveness of groundwater remediation systems, it is important to examine how existing remediation systems respond to changing geophysical (e.g. climate change) and social (e.g. improved living standard and changing development needs) conditions. The resilience of remediation strategies, or their potential to adapt to future changes, is a critical sustainability consideration. We intend to examine the resilience of groundwater remediation systems in response to changing conditions. Among others, we explore the effects of sea level rise and changing hydroclimatic conditions on the life cycle impact of phytoremediation and bioremediation systems. The study was conducted in the San Francisco Bay area, where thousands of contaminated sites are located in an area that may be affected by sea level rise and changing hydroclimatic conditions.

  2. Strain Observation Affected by Groundwater-Level Change in Seismic Precursor Monitoring

    Science.gov (United States)

    Zhang, Lei; Cao, Daiyong; Zhang, Jingfa

    2017-03-01

    Groundwater extraction is one of the most typical disturbance factors for strain observation in seismic precursor monitoring. The statistic regression method is used to study based on the relation between the variation of strain and the groundwater level. The least square regression linear model is built between the annual variation of Sangzi groundwater level and the Xiaoxinzhuang strain data. Such model meets t test with significance level α = 0. 0 5, which confirms that groundwater-level change in each year affects strain measurement significantly and strain's trend variation is related to groundwater-level change. Consequently, a new correction method about strain data is put forward based on the groundwater-level annual variation to eliminate the trend change. Results indicate that the accumulated residual deformation causes the horizontal displacement and strain change, which is on account of that the amount of groundwater recharge is less than that of extraction around Xiaoxinzhuang cave, the phreatic surface continues to descend, and residual deformation accumulates and leads to local subsidence area. Therefore, the decline trend change of strain is related to groundwater-level change and is not seismic precursor.

  3. Effects of Soil and Water Conservation Measures on Groundwater Levels and Recharge

    Directory of Open Access Journals (Sweden)

    Hong Wang

    2014-12-01

    Full Text Available Measures of soil and water conservation (SWC could affect the hydrological process. The impacts of typical measures on groundwater recharge, levels and flow were analyzed based on simulated rainfall experiments and a groundwater model. The three-dimensional finite-difference groundwater flow model (MODFLOW was calibrated and verified for bare slope, grassland and straw mulching scenarios based on the experiments. The results of the verification in groundwater balance, levels, runoff and flow field all showed that MODFLOW could be applied to study the impact of SWC measures on groundwater. Meanwhile, the results showed the recharge rate (α and specific yield of the three soil layers (Sy1, Sy2 and Sy3 were the most sensitive parameters to the change in the underlying surface. Then, the impacts of the SWC measures’ construction and destruction on the groundwater regime were studied. The results indicated the measures could strengthen groundwater recharge. The amounts of groundwater recharge, runoff and level were on the order of straw mulching > grassland > bare slope. When the underlying surface was converted from grass and mulching to bare slope, the recharge decreased by 42.2% and 39.1%. It was concluded that SWC measure construction would increase groundwater recharge and the measure destruction would decrease recharge.

  4. Machine learning algorithms for modeling groundwater level changes in agricultural regions of the U.S.

    Science.gov (United States)

    Sahoo, S.; Russo, T. A.; Elliott, J.; Foster, I.

    2017-05-01

    Climate, groundwater extraction, and surface water flows have complex nonlinear relationships with groundwater level in agricultural regions. To better understand the relative importance of each driver and predict groundwater level change, we develop a new ensemble modeling framework based on spectral analysis, machine learning, and uncertainty analysis, as an alternative to complex and computationally expensive physical models. We apply and evaluate this new approach in the context of two aquifer systems supporting agricultural production in the United States: the High Plains aquifer (HPA) and the Mississippi River Valley alluvial aquifer (MRVA). We select input data sets by using a combination of mutual information, genetic algorithms, and lag analysis, and then use the selected data sets in a Multilayer Perceptron network architecture to simulate seasonal groundwater level change. As expected, model results suggest that irrigation demand has the highest influence on groundwater level change for a majority of the wells. The subset of groundwater observations not used in model training or cross-validation correlates strongly (R > 0.8) with model results for 88 and 83% of the wells in the HPA and MRVA, respectively. In both aquifer systems, the error in the modeled cumulative groundwater level change during testing (2003-2012) was less than 2 m over a majority of the area. We conclude that our modeling framework can serve as an alternative approach to simulating groundwater level change and water availability, especially in regions where subsurface properties are unknown.

  5. Assessing the suitability of extreme learning machines (ELM for groundwater level prediction

    Directory of Open Access Journals (Sweden)

    Yadav Basant

    2017-03-01

    Full Text Available Fluctuation of groundwater levels around the world is an important theme in hydrological research. Rising water demand, faulty irrigation practices, mismanagement of soil and uncontrolled exploitation of aquifers are some of the reasons why groundwater levels are fluctuating. In order to effectively manage groundwater resources, it is important to have accurate readings and forecasts of groundwater levels. Due to the uncertain and complex nature of groundwater systems, the development of soft computing techniques (data-driven models in the field of hydrology has significant potential. This study employs two soft computing techniques, namely, extreme learning machine (ELM and support vector machine (SVM to forecast groundwater levels at two observation wells located in Canada. A monthly data set of eight years from 2006 to 2014 consisting of both hydrological and meteorological parameters (rainfall, temperature, evapotranspiration and groundwater level was used for the comparative study of the models. These variables were used in various combinations for univariate and multivariate analysis of the models. The study demonstrates that the proposed ELM model has better forecasting ability compared to the SVM model for monthly groundwater level forecasting.

  6. Responses of submarine groundwater to silty-sand coast reclamation: A case study in south of Laizhou Bay, China

    Science.gov (United States)

    Liu, Sen; Gao, Maosheng; Tang, Zhonghua; Hou, Guohua; Guo, Fei

    2016-11-01

    Coastal reclamation can result in considerable changes in the quality and quantity of submarine groundwater at the land/sea interface. In this study, submarine groundwater monitoring wells and water samples were designed and implemented to get data of groundwater level, electrical conductivity, temperature, and hydrochemistry data to examine the responses of silty-sand submarine groundwater in different sedimentary strata to reclamation in south of Laizhou Bay. The submarine groundwater is mainly saline water and its salinity in the deep aquifer is higher than that of seawater and close to brine. It was formed in the Late Pleistocene and Holocene. Drilling core data indicates that there is a stratigraphic boundary at a depth of 18.58 m, with Holocene strata above, and Late Pleistocene strata below, this level. Continuous electrical conductivity data indicates that the submarine groundwater properties are stratigraphically distributed in this study area. And there is an interface at a depth of 38 m. Above the 38 m depth, the water quantity of submarine ground-saline water is freshening. The major ions showed a tendency to change continually above 25 m, but the tended to stabilize below 25 m depth. Freshwater is the major recharge source in the upper section of the Holocene strata, between the surface and 8.00 m depth, and the hydrochemical type has changed from Clsbnd Na to Cl·HCO3sbnd Na. In the lower section of Holocene strata (8.00-23.00 m) and upper section of late Late Pleistocene strata (23.00-38.00 m), groundwater is influenced by seawater and groundwater of upper aquifer. The freshwater, seawater, and groundwater recharge in the upper aquifer has no influence on the groundwater in the section below the late Late Pleistocene (between 38.00 and 49.15 m) and the early Late Pleistocene strata (between 49.15 and 75.00 m). The filling layer, added in the coastal reclamation project, is comprised of clayey silt and fine sand, and its high porosity means that it is

  7. Data-driven behavioural characterization of dry-season groundwater-level variation in Maharashtra, India

    Indian Academy of Sciences (India)

    Rahul Gokhale; Milind Sohoni

    2015-06-01

    This paper looks at the crucial issue of dry-season groundwater-availability in the state of Maharashtra, India. We look at the two key hydro-climatological measurements which are used to implement ground-water policy in the state, viz., water levels in 5000+ observation wells across the state and aggregate rainfall data. We see that there is substantial variation in groundwater levels within and across the years in most wells. We argue that for a large number of these observation well locations, aggregate rainfall data is inadequate to model or to predict groundwater levels. For this, we use a novel random rainfall coefficient model for the purpose of modelling the effect of rainfall in a composite setting where extraction and changing land-use data is unknown. The observed high variance of this coefficient points to significant variations in groundwater levels, which may only be explained by unmeasured anthropogenic factors. Next, we see that the uncertainty in actual groundwater levels along with scarcity are two distinct features of groundwater availability and will elicit different behaviours from the typical user. Finally, we recommend that quantitative groundwater assessment protocols of the state should move to incorporating data from which extraction and land-use may be modelled. We believe this is one of the first studies where large spatio-temporal scale data gathered by state agencies have been analysed for scientific adequacy.

  8. Nitrate levels and the age of groundwater from the Upper Devonian sandstone aquifer in Fife, Scotland.

    Science.gov (United States)

    McNeill, G W; Anderson, J; Elliot, T

    2003-03-01

    The tritium concentrations in 13 groundwater samples from boreholes throughout the Upper Devonian sandstone aquifer of Fife have been measured. Due to atmospheric variations in tritium concentrations over the last century, this radioactive tracer can be used as a groundwater age indicator. In this study, the groundwater tritium concentrations have allowed for the area to be divided into three zones, and the variable chemistry of the groundwater samples, including the problem of recent elevated nitrate levels in the Fife Aquifer, has been interpreted in terms of their relative ages.

  9. Prediction of monthly regional groundwater levels through hybrid soft-computing techniques

    Science.gov (United States)

    Chang, Fi-John; Chang, Li-Chiu; Huang, Chien-Wei; Kao, I.-Feng

    2016-10-01

    Groundwater systems are intrinsically heterogeneous with dynamic temporal-spatial patterns, which cause great difficulty in quantifying their complex processes, while reliable predictions of regional groundwater levels are commonly needed for managing water resources to ensure proper service of water demands within a region. In this study, we proposed a novel and flexible soft-computing technique that could effectively extract the complex high-dimensional input-output patterns of basin-wide groundwater-aquifer systems in an adaptive manner. The soft-computing models combined the Self Organized Map (SOM) and the Nonlinear Autoregressive with Exogenous Inputs (NARX) network for predicting monthly regional groundwater levels based on hydrologic forcing data. The SOM could effectively classify the temporal-spatial patterns of regional groundwater levels, the NARX could accurately predict the mean of regional groundwater levels for adjusting the selected SOM, the Kriging was used to interpolate the predictions of the adjusted SOM into finer grids of locations, and consequently the prediction of a monthly regional groundwater level map could be obtained. The Zhuoshui River basin in Taiwan was the study case, and its monthly data sets collected from 203 groundwater stations, 32 rainfall stations and 6 flow stations during 2000 and 2013 were used for modelling purpose. The results demonstrated that the hybrid SOM-NARX model could reliably and suitably predict monthly basin-wide groundwater levels with high correlations (R2 > 0.9 in both training and testing cases). The proposed methodology presents a milestone in modelling regional environmental issues and offers an insightful and promising way to predict monthly basin-wide groundwater levels, which is beneficial to authorities for sustainable water resources management.

  10. Groundwater Level Fluctuation Forecasting in Birjand Aquifer Using Artificial Neural Network

    Science.gov (United States)

    Mirarabi, A.; Nakhaei, M.

    2009-04-01

    Artificial Neural Networks (ANNs) are being used increasingly to predict and forecast water resources variables such as groundwater levels. In this paper using artificial neural network three objective including determination of the influential parameters which impact fluctuation of groundwater level in birjand aquifer, investigation of the effect of temporal and spatial information by considering time series (9 years) and simulation of the fluctuation groundwater level in three selected piezometers are recognized. The reasonably good prediction of piezometric level simulated based on ANN using FNN_LM by selection of effective parameters and optimal time lag

  11. 1:750,000-scale static ground-water levels of Nevada

    Data.gov (United States)

    U.S. Geological Survey, Department of the Interior — This data set consists of static ground-water levels for the State of Nevada based on a 1974 ground-water map (Rush, 1974) published by the Nevada Department of...

  12. Analysis of Aquifer Response, Groundwater Flow, and PlumeEvolution at Site OU 1, Former Fort Ord, California

    Energy Technology Data Exchange (ETDEWEB)

    Jordan, Preston D.; Oldenburg, Curtis M.; Su, Grace W.

    2005-02-24

    This report presents a continuation from Oldenburg et al. (2002) of analysis of the hydrogeology, In-Situ Permeable Flow Sensor (ISPFS) results, aquifer response, and changes in the trichloroethylene (TCE) groundwater plume at Operational Unit 1 (OU 1) adjacent to the former Fritzsche Army Airfield at the former Fort Ord Army Base, located on Monterey Bay in northern Monterey County. Fuels and solvents were burned on a portion of OU 1 called the Fire Drill Area (FDA) during airport fire suppression training between 1962 and 1985. This activity resulted in soil and groundwater contamination in the unconfined A-aquifer. In the late 1980's, soil excavation and bioremediation were successful in remediating soil contamination at the site. Shortly thereafter, a groundwater pump, treat, and recharge system commenced operation. This system has been largely successful at remediating groundwater contamination at the head of the groundwater plume. However, a trichloroethylene (TCE) groundwater plume extends approximately 3000 ft (900 m) to the northwest away from the FDA. In the analyses presented here, we augment our prior work (Oldenburg et al., 2002) with new information including treatment-system totalizer data, recent water-level and chemistry data, and data collected from new wells to discern trends in contaminant migration and groundwater flow that may be useful for ongoing remediation efforts. Some conclusions from the prior study have been modified based on these new analyses, and these are pointed out clearly in this report.

  13. Global assessment of vulnerability to sea-level rise in topography-limited and recharge-limited coastal groundwater systems

    Science.gov (United States)

    Michael, Holly A.; Russoniello, Christopher J.; Byron, Lindsay A.

    2013-04-01

    Impacts of rising sea level on the hydraulic balance between aquifers and the ocean threaten fresh water resources and aquatic ecosystems along many world coastlines. Understanding the vulnerability of groundwater systems to these changes and the primary factors that determine the magnitude of system response is critical to developing effective management and adaptation plans in coastal zones. We assessed the vulnerability of two types of groundwater systems, recharge-limited and topography-limited, to changes caused by sea-level rise over a range of hydrogeologic settings. Vulnerability in this context is defined by the rate and magnitude of salinization of coastal aquifers and changes in groundwater flow to the sea. Two-dimensional variable-density groundwater flow and salt transport simulations indicate that the response of recharge-limited systems is largely minimal, whereas topography-limited systems are vulnerable for various combinations of permeability, vertical anisotropy in permeability, and recharge. World coastlines were classified according to system type as a vulnerability indicator. Results indicate that approximately 70% of world coastlines may be topography-limited, though variability in hydrogeologic conditions strongly affects classification. Future recharge and sea-level rise scenarios have much less influence on the proportion of vulnerable coastlines than differences in permeability, distance to a hydraulic divide, and recharge, indicating that hydrogeologic properties and setting are more important factors to consider in determining system type than uncertainties in the magnitude of sea-level rise and hydrologic shifts associated with future climate change.

  14. Regional scale assessment of soil predictors of groundwater phosphate (P) levels in acidic sandy agricultural soils

    Science.gov (United States)

    Mabilde, Lisa

    2016-04-01

    Possible factors affecting the leaching of P to the groundwater in the Belgian sandy area are examined via regression analysis. The main objective is to investigate the dependency of phreatic groundwater phosphate concentrations (Flemish VMM monitoring net, monitoring period 2010-2013) on soil phosphate saturation degree (PSD) (1994-1997 mapping for Flemish Land Agency) (n = 1032). Additionally explored parameters include: depth distributions of Fe- and Al-oxides, sorbed P and phosphate sorption capacity (PSC) and soil pH. Interpolated data of these soil parameters in 3 depth layers (0-30, 30-60, 60-90 cm) were generated by ordinary kriging. Secondly, we assessed the significance of other edaphic factors potentially controlling the groundwater P: topsoil organic carbon content (OC %), soil clay content and fluctuation of the groundwater table. Overall, the mean PSD halved with each 30 cm depth layer (56 > 24 > 13 %) and was correlated to groundwater PO43- level. The statistical significance of the correlation with groundwater PO43- concentrations increased with depth layer. The poor correlation (R2 = 0.01) between PSD and groundwater phosphate concentration indicates that many factors, other than soil P status, control the transport of P from soil solution to the groundwater in Belgian sandy soils. A significant (PStructural equation modeling for example could be used to understand the practical importance of individual soil, management and hydrological potential predictors of groundwater PO4.

  15. Evaluating mountain meadow groundwater response to Pinyon-Juniper and temperature in a great basin watershed

    Science.gov (United States)

    Carroll, Rosemary W.H.; Huntington, Justin L.; Snyder, Keirith A.; Niswonger, Richard G.; Morton, Charles; Stringham, Tamzen K.

    2017-01-01

    This research highlights development and application of an integrated hydrologic model (GSFLOW) to a semiarid, snow-dominated watershed in the Great Basin to evaluate Pinyon-Juniper (PJ) and temperature controls on mountain meadow shallow groundwater. The work used Google Earth Engine Landsat satellite and gridded climate archives for model evaluation. Model simulations across three decades indicated that the watershed operates on a threshold response to precipitation (P) >400 mm/y to produce a positive yield (P-ET; 9%) resulting in stream discharge and a rebound in meadow groundwater levels during these wetter years. Observed and simulated meadow groundwater response to large P correlates with above average predicted soil moisture and with a normalized difference vegetation index threshold value >0.3. A return to assumed pre-expansion PJ conditions or an increase in temperature to mid-21st century shifts yielded by only ±1% during the multi-decade simulation period; but changes of approximately ±4% occurred during wet years. Changes in annual yield were largely dampened by the spatial and temporal redistribution of evapotranspiration across the watershed: Yet the influence of this redistribution and vegetation structural controls on snowmelt altered recharge to control water table depth in the meadow. Even a small-scale removal of PJ (0.5 km2) proximal to the meadow will promote a stable, shallow groundwater system resilient to droughts, while modest increases in temperature will produce a meadow susceptible to declining water levels and a community structure likely to move toward dry and degraded conditions.

  16. COMPARISON OF DETEMINISTIC INTERPOLATION METHODS FOR THE ESTIMATION OF GROUNDWATER LEVEL

    Directory of Open Access Journals (Sweden)

    Agnieszka Kamińska

    2014-10-01

    Full Text Available This paper compares two spatial interpolation techniques – Radial Basis Functions (RBF and Inverse Distance Weighting (IDW – with the goal of determining which method creates the best representation of reality for measured groundwater levels in catchment area. The study used the results of research and field observations from the year 2011, in Sosnowica (West Polesie. The data set consists of groundwater levels measured at 15 points in three series of tests. Surface generation was obtained for each method. The water prediction maps showed spatial variation in the groundwater level in the study area and they are quite different. RBF method resulted in a smoother map. The analysis of the methods of interpolation of analyzed data with the help of cross validation statistics and plots showed that Radial Basis Functions creates better representation of reality for measured groundwater levels.

  17. Microbial Community-Level Physiological Profiles (CLPP) and herbicide mineralization potential in groundwater affected by agricultural land use

    Science.gov (United States)

    Janniche, Gry Sander; Spliid, Henrik; Albrechtsen, Hans-Jørgen

    2012-10-01

    Diffuse groundwater pollution from agricultural land use may impact the microbial groundwater community, which was investigated as Community-Level Physiological Profiles (CLPP) using EcoPlate™. Water was sampled from seven piezometers and a spring in a small agricultural catchment with diffuse herbicide and nitrate pollution. Based on the Shannon-Wiener and Simpson's diversity indices the diversity in the microbial communities was high. The response from the EcoPlates™ showed which substrates support groundwater bacteria, and all 31 carbon sources were utilized by organisms from at least one water sample. However, only nine carbon sources were utilized by all water samples: D-Mannitol, N-acetyl-D-glucosamine, putrescine, D-galacturonic acid, itaconic acid, 4-hydroxy benzoic acid, tween 40, tween 80, and L-asparagine. In all water samples the microorganisms preferred D-mannitol, D-galacturonic acid, tween 40, and 4-hydroxy benzoic acid as substrates, whereas none preferred 2-hydroxy benzoic acid, α-D-lactose, D,L-α-glycerol phosphate, α-ketobutyric acid, L-threonine and glycyl-L-glutamic acid. Principal Component Analysis of the CLPP's clustered the most agriculturally affected groundwater samples, indicating that the agricultural land use affects the groundwater microbial communities. Furthermore, the ability to mineralize atrazine and isoproturon, which have been used in the catchment, was also associated with this cluster.

  18. Study on the change rule of groundwater level and its impacts on vegetation at arid mining area

    Institute of Scientific and Technical Information of China (English)

    LEI Shao-gang; BIAN Zheng-fu; ZHANG Ri-chen; LI Lin

    2007-01-01

    The shallow groundwater in Shendong mining area was broken because of large-scale underground mining activities. Selecting 32201 working-face as research area,analyzed the change rule of groundwater level and aquifer thickness under mining impact with a large number of water level observation data. Then, the impacts of groundwater level change on vegetation were analyzed by the relationship theory of arid area groundwater and vegetation. The results show that the aquifer structure and the water condition of supply flow and drainage are changed by the water proof mining. The groundwater level recovere only a little compared with the original groundwater level in two years. But the great change of groundwater level do not have notable influences on vegetation of this mining area, and further study indicates that there are certain conditions where groundwater level change impacted on vegetation. When the influence of groundwater level change was evaluated, the plant ecological water level, warning water level and spatial distribution character of original groundwater and mining-impacted groundwater-level change should be integrated.

  19. Predicting of Groundwater Level Fluctuation Using ANN and ANFIS in Lailakh plain

    Directory of Open Access Journals (Sweden)

    Semko Rashidi

    2016-09-01

    Full Text Available Forecasting of groundwater level and its fluctuations is one of the essential measures(actions for integrated management planning of groundwater resources. Considering the nonlinear and complex relations that govern groundwater flow, designing a precise and simple model is considered as an inevitable necessity for simulating the groundwater resources behavior. Nowadays, the connoisseur systems such as Artificial Neural Networks (ANN and Adaptive Neuro Fuzzy Inference Systems (ANFIS have regarded as the useful and reliable tools for modeling the nonlinear mappings. The purpose of this study is developing the ANN and ANFIS models, to predict water table fluctuations of groundwater resources system in Lailakh Plain. The time-values of monthly average groundwater level, rainfall, temperature and evaporation were used to develop the proposed models. And, ANN and ANFIS dynamic, static andhybrid models were developed for predicting water table depths. Finally, the proposed models were compared and prioritized by the using of Analytical Hierarchy Process (AHP. The resultes of the research showed that the dynamic and static models were respectively the most accurate and careless groundwater table predicting models. The ANN dynamic model with three input parameters and MSE=0.776 and R=0.975, was the best model for the more accurately predicting of water table fluctuations in Lailakh plain.

  20. Isotope techniques for the research of groundwater in the potential site of China’s high-level waste repository

    Institute of Scientific and Technical Information of China (English)

    郭永海; 刘淑芬; 杨天笑; 姜桂林

    2001-01-01

    Using the isotope techniques, the groundwater origin, evolution and circulation in the potential site of China’s high-level waste repository are studied. The results indicate that both shallow groundwaters and deep groundwaters in the site area are of meteoric origin. The shallow groundwaters are mainly recharged by modern and local precipitation, and the deep groundwaters are originated from regional precipitation at higher elevation, or may be from the precipitation during the geological history period with lower temperature. Through the study we can also understand that the deep underground is a very low-permeability system where the groundwater flow-rates are very low.

  1. [Groundwater].

    Science.gov (United States)

    González De Posada, Francisco

    2012-01-01

    From the perspective of Hydrogeology, the concept and an introductory general typology of groundwater are established. From the perspective of Geotechnical Engineering works, the physical and mathematical equations of the hydraulics of permeable materials, which are implemented, by electric analogical simulation, to two unique cases of global importance, are considered: the bailing during the construction of the dry dock of the "new shipyard of the Bahia de Cádiz" and the waterproofing of the "Hatillo dam" in the Dominican Republic. From a physical fundamental perspective, the theories which are the subset of "analogical physical theories of Fourier type transport" are related, among which the one constituted by the laws of Adolf Fick in physiology occupies a historic role of some relevance. And finally, as a philosophical abstraction of so much useful mathematical process, the one which is called "the Galilean principle of the mathematical design of the Nature" is dealt with.

  2. Impact of Groundwater Level on Nitrate Nitrogen Accumulation in the Vadose Zone Beneath a Cotton Field

    Directory of Open Access Journals (Sweden)

    Xiyun Jiao

    2017-02-01

    Full Text Available In this study, the impacts of groundwater level on nitrate nitrogen accumulation in the vadose zone of a cotton field were investigated. Experiments were conducted in a cotton field at the CAS Ecological Agricultural Experiment Station in Nanpi from 2008 to 2010. A vertical observation well was drilled, and time-domain reflectometry probes and soil solution extractors were installed every 50 cm in the walls of the well to a depth of 5 m. The soil water content was monitored, and soil solution samples were obtained and analyzed every six days throughout the growing seasons during the three studied years. Additionally, a water consumption experiment was conducted, and the topsoil water content and leaf area index were measured in the cotton field. The resulting data were used to estimate parameters for use in a soil hydraulic and nitrate nitrogen movement model, and cotton evapotranspiration was calculated using the Penman–Monteith method. Groundwater level increases and decreases of ±4 m were simulated during a ten-year period using HYDRUS-1D. The results showed significant nitrate nitrogen accumulation in the vadose zone when the groundwater level remained unchanged or decreased, with increased accumulation as the groundwater depth increased. Additionally, increased precipitation and a deeper groundwater level resulted in greater nitrate nitrogen leaching in the cotton root zone. Therefore, irrigation and fertilization strategies should be adjusted based on precipitation conditions and groundwater depth.

  3. Application of RBFN network and GM (1, 1) for groundwater level simulation

    Science.gov (United States)

    Li, Zijun; Yang, Qingchun; Wang, Luchen; Martín, Jordi Delgado

    2016-10-01

    Groundwater is a prominent resource of drinking and domestic water in the world. In this context, a feasible water resources management plan necessitates acceptable predictions of groundwater table depth fluctuations, which can help ensure the sustainable use of a watershed's aquifers for urban and rural water supply. Due to the difficulties of identifying non-linear model structure and estimating the associated parameters, in this study radial basis function neural network (RBFNN) and GM (1, 1) models are used for the prediction of monthly groundwater level fluctuations in the city of Longyan, Fujian Province (South China). The monthly groundwater level data monitored from January 2003 to December 2011 are used in both models. The error criteria are estimated using the coefficient of determination (R 2), mean absolute error (E) and root mean squared error (RMSE). The results show that both the models can forecast the groundwater level with fairly high accuracy, but the RBFN network model can be a promising tool to simulate and forecast groundwater level since it has a relatively smaller RMSE and MAE.

  4. Characterizing the regional pattern and temporal change of groundwater levels by analyses of a well log data set

    Institute of Scientific and Technical Information of China (English)

    Mahmuda PARVIN; Naoyuki TADAKUMA; Hisafumi ASAUE; Katsuaki KOIKE

    2011-01-01

    Preservation of the amount and quality of groundwater resources is an important issue around the world.Changes in groundwater levels need to be monitored in efforts to preserve groundwater.This study investigates suitable methods to characterize changes in the groundwater level and determine the factors involved.The area of Kumamoto,a city in central Kyushu,southwest Japan,was selected to demonstrate the usefulness of the methods because this area is one of the richest in Japan in terms of groundwater resources and takes all its water from groundwater.Data of the groundwater level recorded at 69 wells from 1979 to 2007 were used in geostatistical and correlogram analyses.First,strong correlation between the topography and groundwater level was identified.Incorporating this correlation into spatial modeling of the groundwater level,co-kriging was demonstrated to be more accurate than ordinary kriging.The co-kriging results clarified the hydraulic characteristics of the Kumamoto area; the patterns of shallow and deep groundwater levels were agreeable generally,and the general trends of their annual average levels were similar regardless of precipitation.Another important feature was that the correlograms for the precipitation amount and groundwater level had a constant shape and changed smoothly with a change in lag time regardless of the precipitation only in the area of Togawa lava.These characteristics are probably due to the connections between shallow and deep aquifers and the high permeability of Togawa lava.

  5. The range fraction: an applied method to characterize regional groundwater responses to climate inputs.

    Science.gov (United States)

    Leising, Joseph F; Lutz, Alexandra

    2014-12-01

    An important component of ongoing water-resource investigations in the eastern Great Basin, USA, has been to ascertain the impact of future predicted climate change on groundwater availability. As a first step in that analysis, it was hypothesized that potentiometric fluctuations at certain wells would reflect annual-scale precipitation variation. Potentiometric behavior at a well depends on local hydrologic conditions, well construction, and human activities, in addition to natural recharge and regional water levels. Moreover, measurement data are limited for many wells. After preliminarily screening, a large body of well and climate station data, short-term potentiometric responses to annual-scale climate inputs, were identified at 18 wells using a simple visualization methodology developed during the study. For water levels displaying multi-annual trends, the signals were measured as deviations from a linear trendline. Groundwater responses lagged precipitation signals by less than 1 year to as much as 3 years, with most wells showing at most a 1- to 2-year delay. Response amplitude was variable and strongly depended on the hydrologic setting of each well.

  6. Hydrogeology, ground-water use, and ground-water levels in the Mill Creek Valley near Evendale, Ohio

    Science.gov (United States)

    Schalk, Charles; Schumann, Thomas

    2002-01-01

    Withdrawals of ground water in the central Mill Creek Valley near Evendale, Ohio, caused water-level declines of more than 100 feet by the 1950s. Since the 1950s, management practices have changed to reduce the withdrawals of ground water, and recovery of water levels in long-term monitoring wells in the valley has been documented. Changing conditions such as these prompted a survey of water use, streamflow conditions, and water levels in several aquifers in the central Mill Creek Valley, Hamilton and Butler Counties, Ohio. Geohydrologic information, water use, and water levels were compiled from historical records and collected during the regional survey. Data collected during the survey are presented in terms of updated geohydrologic information, water use in the study area, water levels in the aquifers, and interactions between ground water and surface water. Some of the data are concentrated at former Air Force Plant 36 (AFP36), which is collocated with the General Electric Aircraft Engines (GEAE) plant, and these data are used to describe geohydrology and water levels on a more local scale at and near the plant. A comparison of past and current ground-water use and levels indicates that the demand for ground water is decreasing and water levels are rising. Before 1955, most of the major industrial ground-water users had their own wells, ground water was mined from a confined surficial (lower) aquifer, and water levels were more than 100 feet below their predevelopment level. Since 1955, however, these users have been purchasing their water from the city of Cincinnati or a private water purveyor. The cities of Reading and Lockland, both producers of municipal ground-water supplies in the area, shut down their well fields within their city limits. Because the demand for ground-water supplies in the valley has lessened greatly since the 1950s, withdrawals have decreased, and, consequently, water levels in the lower aquifer are 65 to 105 feet higher than they were

  7. Sensitivity of GRACE-derived estimates of groundwater-level changes in southern Ontario, Canada

    Science.gov (United States)

    Hachborn, Ellen; Berg, Aaron; Levison, Jana; Ambadan, Jaison Thomas

    2017-06-01

    Amidst changing climates, understanding the world's water resources is of increasing importance. In Ontario, Canada, low water conditions are currently assessed using only precipitation and watershed-based stream gauges by the Conservation Authorities in Ontario and the Ministry of Natural Resources and Forestry. Regional groundwater-storage changes in Ontario are not currently measured using satellite data by research institutes. In this study, contributions from the Gravity Recovery and Climate Experiment (GRACE) data are compared to a hydrogeological database covering southern Ontario from 2003 to 2013, to determine the suitability of GRACE total water storage estimates for monitoring groundwater storage in this location. Terrestrial water storage data from GRACE were used to determine monthly groundwater storage (GWS) anomaly values. GWS values were also determined by multiplying groundwater-level elevations (from the Provincial Groundwater Monitoring Network wells) by specific yield. Comparisons of GRACE-derived GWS to well-based GWS data determined that GRACE is sufficiently sensitive to obtain a meaningful signal in southern Ontario. Results show that GWS values produced by GRACE are useful for identifying regional changes in groundwater storage in areas with limited available hydrogeological characterization data. Results also indicate that GRACE may have an ability to forecast changes in groundwater storage, which will become useful when monitoring climate shifts in the near future.

  8. Groundwater response to the 2014 pulse flow in the Colorado River Delta

    Science.gov (United States)

    Kennedy, Jeffrey; Rodriguez-Burgueno, Eliana; Ramirez-Hernandez, Jorge

    2017-01-01

    During the March-May 2014 Colorado River Delta pulse flow, approximately 102 × 106 m3 (82,000 acre-feet) of water was released into the channel at Morelos Dam, with additional releases further downstream. The majority of pulse flow water infiltrated and recharged the regional aquifer. Using groundwater-level and microgravity data we mapped the spatial and temporal distribution of changes in aquifer storage associated with pulse flow. Surface-water losses to infiltration were greatest around the Southerly International Boundary, where a lowered groundwater level owing to nearby pumping created increased storage potential as compared to other areas with shallower groundwater. Groundwater levels were elevated for several months after the pulse flow but had largely returned to pre-pulse levels by fall 2014. Elevated groundwater levels in the limitrophe (border) reach extended about 2 km to the east around the midway point between the Northerly and Southerly International Boundaries, and about 4 km to the east at the southern end. In the southern part of the delta, although total streamflow in the channel was less due to upstream infiltration, augmented deliveries through irrigation canals and possible irrigation return flows created sustained increases in groundwater levels during summer 2014. Results show that elevated groundwater levels and increases in groundwater storage were relatively short lived (confined to calendar year 2014), and that depressed water levels associated with groundwater pumping around San Luis, Arizona and San Luis Rio Colorado, Sonora cause large, unavoidable infiltration losses of in-channel water to groundwater in the vicinity.

  9. Spatiotemporal Characteristics of Groundwater Drought and Its Response to Meteorological Drought in Jiangsu Province, China

    Directory of Open Access Journals (Sweden)

    Bo Liu

    2016-10-01

    Full Text Available In this study, the temporal and spatial variations of groundwater drought using a Standardized Groundwater Level Index (SGI were analyzed based on 40 monthly groundwater level observation wells from 1989 to 2012 in Jiangsu Province, China. Meteorological drought, calculated by the Standardized Precipitation Index (SPI, was also included to reveal its propagation and impact on the groundwater drought process. Results showed that the southern region of Jiangsu faced more frequent groundwater droughts and lower intensity, while the northern region faced less frequent groundwater drought with higher intensity. Furthermore, the cross-correlation between the spatial average of SGI and SPI for SPI accumulation periods of q = 1 to 12 was computed. The relationship between SGI and SPI varied in different regions. Detailed analysis of the characteristics of groundwater and meteorological drought for each region showed that meteorological droughts happened more frequently than groundwater drought in Jiangsu Province during the study period, while the mean duration and mean magnitude of groundwater droughts were longer and larger than those of meteorological droughts. It is expected that this study will provide useful information for drought monitoring and mitigation in Jiangsu and similar areas.

  10. Fe and Mn levels regulated by agricultural activities in alluvial groundwaters underneath a flooded paddy field

    Energy Technology Data Exchange (ETDEWEB)

    Kim, Kangjoo [School of Civil and Environmental Engineering, Kunsan National University, Jeonbuk 573-701 (Korea, Republic of)], E-mail: kangjoo@kunsan.ac.kr; Kim, Hyun-Jung; Choi, Byoung-Young; Kim, Seok-Hwi; Park, Ki-hoon [School of Civil and Environmental Engineering, Kunsan National University, Jeonbuk 573-701 (Korea, Republic of); Park, Eungyu [Department of Geology, Kyungpook National University, Daegu 702-701 (Korea, Republic of); Koh, Dong-Chan [Korea Institute of Geoscience and Mineral Resources, Daejeon 305-350 (Korea, Republic of); Yun, Seong-Taek [Department of Earth and Environmental Sciences, Korea University, Seoul 136-701 (Korea, Republic of)

    2008-01-15

    Iron and Mn concentrations in fresh groundwaters of alluvial aquifers are generally high in reducing conditions reflecting low SO{sub 4} concentrations. The mass balance and isotopic approaches of this study demonstrate that reduction of SO{sub 4}, supplied from agricultural activities such as fertilization and irrigation, is important in lowering Fe and Mn levels in alluvial groundwaters underneath a paddy field. This study was performed to investigate the processes regulating Fe and Mn levels in groundwaters of a point bar area, which has been intensively used for flood cultivation. Four multilevel-groundwater samplers were installed to examine the relationship between geology and the vertical changes in water chemistry. The results show that Fe and Mn levels are regulated by the presence of NO{sub 3} at shallow depths and by SO{sub 4} reduction at the greater depths. Isotopic and mass balance analyses revealed that NO{sub 3} and SO{sub 4} in groundwater are mostly supplied from the paddy field, suggesting that the Fe-and Mn-rich zone of the study area is confined by the agricultural activities. For this reason, the geologic conditions controlling the infiltration of agrochemicals are also important for the occurrence of Fe/Mn-rich groundwaters in the paddy field area.

  11. Evaluation of groundwater levels in the South Platte River alluvial aquifer, Colorado, 1953-2012, and design of initial well networks for monitoring groundwater levels

    Science.gov (United States)

    Wellman, Tristan

    2015-01-01

    The South Platte River and underlying alluvial aquifer form an important hydrologic resource in northeastern Colorado that provides water to population centers along the Front Range and to agricultural communities across the rural plains. Water is regulated based on seniority of water rights and delivered using a network of administration structures that includes ditches, reservoirs, wells, impacted river sections, and engineered recharge areas. A recent addendum to Colorado water law enacted during 2002-2003 curtailed pumping from thousands of wells that lacked authorized augmentation plans. The restrictions in pumping were hypothesized to increase water storage in the aquifer, causing groundwater to rise near the land surface at some locations. The U.S. Geological Survey (USGS), in cooperation with the Colorado Water Conservation Board and the Colorado Water Institute, completed an assessment of 60 years (yr) of historical groundwater-level records collected from 1953 to 2012 from 1,669 wells. Relations of "high" groundwater levels, defined as depth to water from 0 to 10 feet (ft) below land surface, were compared to precipitation, river discharge, and 36 geographic and administrative attributes to identify natural and human controls in areas with shallow groundwater.

  12. Fluctuations in groundwater levels related to regional and local withdrawals in the fractured-bedrock groundwater system in northern Wake County, North Carolina, March 2008-February 2009

    Science.gov (United States)

    Chapman, Melinda J.; Almanaseer, Naser; McClenney, Bryce; Hinton, Natalie

    2011-01-01

    February 2009. Correlation of groundwater-level distribution patterns with orientations of geologic structures obtained from surficial mapping, borehole geophysical measurements, and interpretation of fracture traces suggests two dominant trends striking north-south and N. 65 degrees W. A variation in overall response to groundwater withdrawals was noted in the continuous groundwater-level records for the monitored observation wells and dewatered private wells. The largest overall declines during the study period were observed in an observation well in which the water-level declined as much as 247 feet from mid-July through early August 2008, during a period of heavy usage. A private well had a water-level decline of about 94 feet during the same monitoring period. The large declines recorded in the observation well and the private well indicated a substantial temporary loss of storage in the fractured-bedrock aquifer near the wells, thus reducing the amount of water available to shallow wells in the area (those wells with total depths of about 300 feet), and resulting in temporary well failures until such time as the aquifer recovered.

  13. Groundwater Level Changes Due to Extreme Weather—An Evaluation Tool for Sustainable Water Management

    Directory of Open Access Journals (Sweden)

    Jadwiga R. Ziolkowska

    2017-02-01

    Full Text Available In the past decade, extreme and exceptional droughts have significantly impacted many economic sectors in the US, especially in California, Oklahoma, and Texas. The record drought of 2011–2014 affected almost 90% of Texas areas and 95% of Oklahoma state areas. In 2011 alone, around $1.6 billion in agricultural production were lost as a result of drought in Oklahoma, and $7.6 billion in Texas. The agricultural sectors in Oklahoma and Texas rely mainly on groundwater resources from the non-replenishable Ogallala Aquifer in Panhandle and other aquifers around the states. The exceptional droughts of 2011–2014 not only caused meteorologically induced water scarcity (due to low precipitation, but also prompted farmers to overuse groundwater to maintain the imperiled production. Comprehensive studies on groundwater levels, and thus the actual water availability/scarcity across all aquifers in Oklahoma and Texas are still limited. Existing studies are mainly focused on a small number of selected sites or aquifers over a short time span of well monitoring, which does not allow for a holistic geospatial and temporal evaluation of groundwater level variations. This paper aims at addressing those issues with the proposed geospatial groundwater visualization model to assess availability of groundwater resources for agricultural, industrial, and municipal uses both in Oklahoma and Texas in the time frame of 2003–2014. The model is an evaluation tool that can be used by decision-makers for designing sustainable water management practices and by teachers and researchers for educational purposes.

  14. Screening-level risk assessment for styrene-acrylonitrile (SAN) trimer detected in soil and groundwater.

    Science.gov (United States)

    Kirman, C R; Gargas, M L; Collins, J J; Rowlands, J C

    2012-01-01

    A screening-level risk assessment was conducted for styrene-acrylonitrile (SAN) Trimer detected at the Reich Farm Superfund site in Toms River, NJ. Consistent with a screening-level approach, on-site and off-site exposure scenarios were evaluated using assumptions that are expected to overestimate actual exposures and hazards at the site. Environmental sampling data collected for soil and groundwater were used to estimate exposure point concentrations. Several exposure scenarios were evaluated to assess potential on-site and off-site exposures, using parameter values for exposures to soil (oral, inhalation of particulates, and dermal contact) and groundwater (oral, dermal contact) to reflect central tendency exposure (CTE) and reasonable maximum exposure (RME) conditions. Three reference dose (RfD) values were derived for SAN Trimer for short-term, subchronic, and chronic exposures, based upon its effects on the liver in exposed rats. Benchmark (BMD) methods were used to assess the relationship between exposure and response, and to characterize appropriate points of departure (POD) for each RfD. An uncertainty factor of 300 was applied to each POD to yield RfD values of 0.1, 0.04, and 0.03 mg/kg-d for short-term, subchronic, and chronic exposures, respectively. Because a chronic cancer bioassay for SAN Trimer in rats (NTP 2011a) does not provide evidence of carcinogenicity, a cancer risk assessment is not appropriate for this chemical. Potential health hazards to human health were assessed using a hazard index (HI) approach, which considers the ratio of exposure dose (i.e., average daily dose, mg/kg-d) to toxicity dose (RfD, mg/kg-d) for each scenario. All CTE and RME HI values are well below 1 (where the average daily dose is equivalent to the RfD), indicating that there is no concern for potential noncancer effects in exposed populations even under the conservative assumptions of this screening-level assessment.

  15. Resolving discrepancies between hydraulic and chemical calibration data for seawater intrusion groundwater flow models by considering climate-driven sea level change.

    Energy Technology Data Exchange (ETDEWEB)

    J. Chapman; A. Hassan; K. Pohlmann

    2001-10-18

    Groundwater models of seawater intrusion environments can be calibrated using both hydraulic and chemical information. The possible impact of the long-term transient process of sea level change is difficult to identify, but important to accurate simulation of present conditions. The response times of the pressure and chemical fields to major fluctuations in sea level change are investigated

  16. Irrigator responses to groundwater resource management in northern Victoria, southeastern Australia

    Science.gov (United States)

    Gill, Bruce C.; Webb, John; Wilkinson, Roger; Cherry, Don

    2014-10-01

    In northern Victoria, farmers are the biggest users of groundwater and therefore the main stakeholders in plans that seek to sustainably manage the resource. Interviews with 30 irrigation farmers in two study areas, analysed using qualitative social research methods, showed that the overwhelming majority of groundwater users agreed with the need for groundwater management and thought that the current plans had achieved sustainable resource use. The farmers also expressed a strong need for clear technical explanations for management decisions, in particular easily understood water level data. The social licence to implement the management plans arose through effective consultation with the community during plan development. Several additional factors combined to gain acceptance for the plans: good data on groundwater usage and aquifer levels is available; irrigation farmers had been exposed to usage restrictions since the late 1990s; an ‘adaptive’ management approach is in use which allowed refinements to be readily incorporated and fortuitously, plan development coincided with the 1998-2009 drought, when declines in groundwater levels reinforced the usefulness of the plans. The imposition of a nation-wide water use reduction plan in 2012 had relatively little impact in Victoria because of the early implementation of effective groundwater management plans. However, economic difficulties that reduce groundwater users’ capacity to pay groundwater management charges mean that the future of the plans in Victoria is not assured. Nevertheless, the high level of trust that exists between Victorian irrigation farmers and the management agencies suggests that the continued use of a consultative approach will continue to produce workable outcomes. Lessons from the Victorian experience may be difficult to apply in other areas of groundwater use in Australia and overseas, where there may be a quite different history of development and culture of groundwater management.

  17. Aquifer-Circulating Water Curtain Cultivation System To Recover Groundwater Level And Temperature

    Science.gov (United States)

    Kim, Y.; Ko, K.; Chon, C.; Oh, S.

    2011-12-01

    Groundwater temperature, which generally ranges 14 to 16 degree of Celsius all year long, can be said to be 'constant' compared to the amplitude of daily variation of air temperature or surface water. Water curtain cultivating method utilizes this 'constant' groundwater temperature to warm up the inside of greenhouse during winter night by splash groundwater on the roof of inner greenhouse. The area of water curtain cultivation system have increased up to 107.5 square kilometers as of 2006 since when it is first introduced to South Korea in 1984. Groundwater shortage problem became a great issue in a concentrated water curtain cultivation area because the pumped and splashed groundwater is abandoned to nearby stream and natural recharge rate is reduced by greenhouses. The amount of groundwater use for water curtain cultivation system in South Korea is calculated to be 587 million cubic meters which is 35% of national agricultural use of groundwater. A new water curtain cultivation system coupled with aquifer circulating of the splashed groundwater and greenhouse roof-top rainwater harvesting is developed and applied to field site in Nonsan-si, Chungnam province to minimize groundwater shortage problem and recover groundwater level. The aquifer circulating water curtain cultivation system is consist of a pumping well and a injection well of 80 m deep, groundwater transfer and splashing system, recovery tank and rainwater collecting waterway. The distance between injection and pumping well is 15 m and an observation well is installed in the middle of the wells. To characterize hydrogeological properties of this site, hydraulic test such as pumping tests and tracer tests with dye tracer, thermal tracer and ion tracer. Once the integrated system is constructed in this site, hydraulic head in all the wells and temperature of air, recovery tank and groundwater in all the wells are monitored during the operation for 3months in winter season. Hydraulic test and tracer

  18. Theory and Method for Identifying Well Water Level Anomalies in a Groundwater Overdraft Area

    Institute of Scientific and Technical Information of China (English)

    Zhang Suxin; Zhang Ziguang; Ren Xiaoxia; Wang Xiang

    2007-01-01

    The overexploitation of underground water leads to the continuous drawdown of groundwater levels, change of water quality and dry-up in dynamic water level observation wells. Due to land subsidence, the well pipes uplift and the observation piping systems are damaged. These environmental geology problems can present serious difficulties for the identification of earthquake anomalies by groundwater level observation. Basied on hydrogeological theories and methods, the paper analyzes the relations of the water balance state of aquifers with stressstrain conditions and the water level regime, and then discusses preliminarily the theory and method for identifying well water level anomalies in a groundwater overdraft area. The result shows that we can accurately judge the nature of the anomaly according to the diffusion character of the drawdown funnel in the well area in combination with the aforementioned theory and method and multi-year variation patterns obtained from existing data. The results of the research are helpful for distinguishing the influence of single centralized water pumping from the long-term overdraft of water on the water level, correctly recognizing water level anomalies in the groundwater overdraft area and increasing the level of earthquake analysis and prediction.

  19. Hydrologic and nutrient response of groundwater to flooding of cranberry farms in southeastern Massachusetts, USA

    Science.gov (United States)

    Kennedy, Casey D.

    2015-06-01

    Seasonal flooding of cranberry farms is essential for commercial production of cranberries in southeastern Massachusetts, with close to 90% of growers using a flood for harvesting and winter protection. Although periodic flooding results in increased groundwater recharge, it may also exacerbate subsurface transport of dissolved forms of nitrogen and phosphorus. Given the paucity of information on groundwater exchange with cranberry floodwaters, hydrometric measurements were used to solve for the residual term of groundwater recharge in water budgets for three cranberry farms during the harvest and winter floods. Combined with continuous monitoring of water-table depth and discrete sampling of groundwater for analysis of nitrate (NO3-), ammonium (NH4+), and total dissolved phosphorus (TDP), values of groundwater recharge were used to evaluate the hydrologic and nutrient response of groundwater to flooding of cranberry farms. Mean values of groundwater recharge were 11 (±6) and 47 (±11) cm for the harvest and winter floods, respectively (one standard deviation in parentheses). The factor-of-four difference in ground recharge was related to flood holding times that, on average, were twenty days longer for the winter flood. The total estimated seasonal groundwater recharge of 58 cm was about four times higher than that assigned to cranberry farms in regional groundwater flow models. During the floods, 10 to 20-cm increases in water-table depth were observed for wells within 10 m of the farm, contrasting with decreases (or minimal variation) in water-table depth for wells located 100 m or farther from the farm. These spatial patterns in the hydrologic response of groundwater suggested a zone of influence of approximately 100 m from the flooded edge of the farm. Analysis of 43 groundwater samples collected from 10 wells indicated generally low concentrations of TDP in groundwater (edge of farms). For one groundwater well located in proximity to the farm (∼10 m

  20. Response of selenium concentrations in groundwater to seasonal canal leakage, lower Gunnison River Basin, Colorado, 2013

    Science.gov (United States)

    Linard, J.I.; McMahon, P.B.; Arnold, L.R.; Thomas, J.C.

    2016-05-23

    Selenium is a water-quality concern in the lower Gunnison River Basin because irrigation water interacting with seleniferous soils derived from the Mancos Shale Formation has mobilized selenium and increased its concentrations in surface water. Understanding the occurrence of elevated selenium concentrations in groundwater is necessary because groundwater discharge is an important source of selenium in surface water in the basin. In 2013, the U.S. Geological Survey, in cooperation with the Bureau of Reclamation and the Colorado Water Conservation Board, began a study to understand how changes in groundwater levels attributed to canal leakage affected the concentrations and speciation of dissolved selenium in groundwater. The purpose of this report is to characterize the groundwater adjacent to an unlined leaky canal. Two locations, near the East Canal (W-N1 and W-N2) and farther from the East Canal (W-M1 and W-M2), were selected for nested monitoring well installations. The pressure exerted by changes in canal stage was more readily transferred to the deep groundwater measured in the W-N1 near the canal than the shallow groundwater at the W-N2 well. No definitive relation could be made between canal water-level elevation and water-level elevations in monitoring wells farther from the canal (W-M1 and W-M2). 

  1. A method to filter out the effect of river stage fluctuation on groundwater level using time series models

    Science.gov (United States)

    Yoon, Heesung; Park, Eungyu; Yoon, Pilsun; Lee, Eunhee; Kim, Gyoo-Bum

    2016-04-01

    A method to filter out the effect of river stage fluctuations on groundwater level was designed using an artificial neural network-based time series model of groundwater level prediction. The designed method was applied to daily groundwater level data near the Gangjeong-Koryeong Barrage in the Nakdong river, South Korea. First, one-step ahead direct prediction time series models were successfully developed for both cases of before and after the barrage construction using past measurement data of rainfall, river stage, and groundwater level as inputs. The correlation coefficient values between observed and predicted data were over 0.97. Based on the direct prediction models, recursive prediction models for the simulation of groundwater level fluctuations were designed. The effect of river stage fluctuation on groundwater level data was filtered out by setting a constant value for river stage inputs of the recursive time series models. The hybrid water table fluctuation method was employed to estimate the groundwater recharge using the filtered data. The calculated ratios of groundwater recharge to precipitation before and after the barrage construction were 11.0% and 4.3%, respectively. It is expected that the proposed method can be a useful tool for groundwater level prediction and recharge estimation in the riverside area.

  2. Hydrographs showing groundwater levels for selected wells in the Puyallup River watershed and vicinity, Pierce and King Counties, Washington

    Science.gov (United States)

    Lane, R.C.; Julich, R.J.; Justin, G.B.

    2013-01-01

    Hydrographs of groundwater levels for selected wells in and adjacent to the Puyallup River watershed in Pierce and King Counties, Washington, are presented using an interactive Web-based map of the study area to illustrate changes in groundwater levels on a monthly and seasonal basis. The interactive map displays well locations that link to the hydrographs, which in turn link to the U.S. Geological Survey National Water Information System, Groundwater Site Inventory System.

  3. Hydrographs Showing Groundwater Level Changes for Selected Wells in the Chambers-Clover Creek Watershed and Vicinity, Pierce County, Washington

    Science.gov (United States)

    Justin, G.B.; Julich, R.; Payne, K.L.

    2009-01-01

    Selected groundwater level hydrographs for the Chambers-Clover Creek watershed (CCCW) and vicinity, Washington, are presented in an interactive web-based map to illustrate changes in groundwater levels in and near the CCCW on a monthly and seasonal basis. Hydrographs are linked to points corresponding to the well location on an interactive map of the study area. Groundwater level data and well information from Federal, State, and local agencies were obtained from the U.S. Geological Survey National Water Information System (NWIS), Groundwater Site Inventory (GWSI) System.

  4. Ground-water levels and directions of flow in Geauga County, Ohio, September 1994, and changes in ground-water levels, 1986-94

    Science.gov (United States)

    Jagucki, M.L.; Lesney, L.L.

    1995-01-01

    This report presents the results of a study by the U.S. Geological Survey, in cooperation with Geauga County Planning Commission and Board of County Commissioners, to determine directions of ground-water flow and to assess differences from 1986 to 1994 in ground-water levels in the glacial deposits and Pottsville Formation, Cuyahoga Group, and the Berea Sandstone. Water levels were measured in 219 wells in Geauga County, Ohio, in September 1994. Water levels measured in January and February 1986 in 88 of the 219 wells were used for comparison. Water-level maps constructed from measurements made in September 1994 to show that ground-water levels in the Pottsville Formation and the glacial deposits generally correspond to the land-surface configuration and that ground water flows from the uplands to adjacent streams and buried valleys. Ground-water flow in the Cuyahoga Group is generally downward from the Pottsville Formation to the Berea Sandstone. Directions of ground-water flow in the Berea Sandstone are toward outcrop areas at the north and east edges of Geauga County and toward sub-crops beneath buried glacial valley deposits in Chardon, Chester, Munson, and Russel Townships and along the west edge of the county. A comparison of water level measurements in 1986 and 1994 indicates that water levels declined in 70 percent of the measured wells and increased in 30 percent. The change in water levels from 1986 to 1994 ranged from an increase of 13.58 feet to a decrease of 29.25 feet. Thirty percent of all water-level changes were less than 1 foot in magnitude. In nearly 80 percent of the wells, water-level changes were within the range of plus or minus 5 feet. Among the wells for which two or more historical measurements were available, the 1994 water levels in 54 percent were outside the range of water-levels observed in previous studies (only 24 percent were greater than 1 foot outside of the previously-observed range). Water-level declines of greater than 10 feet

  5. Geostatistics-based groundwater-level monitoring network design and its application to the Upper Floridan aquifer, USA.

    Science.gov (United States)

    Bhat, Shirish; Motz, Louis H; Pathak, Chandra; Kuebler, Laura

    2015-01-01

    A geostatistical method was applied to optimize an existing groundwater-level monitoring network in the Upper Floridan aquifer for the South Florida Water Management District in the southeastern United States. Analyses were performed to determine suitable numbers and locations of monitoring wells that will provide equivalent or better quality groundwater-level data compared to an existing monitoring network. Ambient, unadjusted groundwater heads were expressed as salinity-adjusted heads based on the density of freshwater, well screen elevations, and temperature-dependent saline groundwater density. The optimization of the numbers and locations of monitoring wells is based on a pre-defined groundwater-level prediction error. The newly developed network combines an existing network with the addition of new wells that will result in a spatial distribution of groundwater monitoring wells that better defines the regional potentiometric surface of the Upper Floridan aquifer in the study area. The network yields groundwater-level predictions that differ significantly from those produced using the existing network. The newly designed network will reduce the mean prediction standard error by 43% compared to the existing network. The adoption of a hexagonal grid network for the South Florida Water Management District is recommended to achieve both a uniform level of information about groundwater levels and the minimum required accuracy. It is customary to install more monitoring wells for observing groundwater levels and groundwater quality as groundwater development progresses. However, budget constraints often force water managers to implement cost-effective monitoring networks. In this regard, this study provides guidelines to water managers concerned with groundwater planning and monitoring.

  6. Groundwater response to serial stream stage fluctuations in shallow unconfined alluvial aquifers along a regulated stream (West Virginia, USA)

    Science.gov (United States)

    Maharjan, Madan; Donovan, Joseph J.

    2016-12-01

    Groundwater response to stream stage fluctuations was studied in two unconfined alluvial aquifers using a year-long time series of stream stages from two pools along a regulated stream in West Virginia, USA. The purpose was to analyze spatial and temporal variations in groundwater/surface-water interaction and to estimate induced infiltration rate and cumulative bank storage during an annual cycle of stream stage fluctuation. A convolution-integral method was used to simulate aquifer head at different distances from the stream caused by stream stage fluctuations and to estimate fluxes across the stream-aquifer boundary. Aquifer diffusivities were estimated by wiggle-matching time and amplitude of modeled response to multiple observed storm events. The peak lag time between observed stream and aquifer stage peaks ranged between 14 and 95 hour. Transient modeled diffusivity ranged from 1,000 to 7,500 m2/day and deviated from the measured and calculated single-peak stage-ratio diffusivity by 14-82 %. Stream stage fluctuation displayed more primary control over groundwater levels than recharge, especially during high-flow periods. Dam operations locally altered groundwater flow paths and velocity. The aquifer is more prone to surface-water control in the upper reaches of the pools where stream stage fluctuations are more pronounced than in the lower reaches. This method could be a useful tool for quick assessment of induced infiltration rate and bank storage related to contamination investigations or well-field management.

  7. Groundwater-level trends and forecasts, and salinity trends, in the Azraq, Dead Sea, Hammad, Jordan Side Valleys, Yarmouk, and Zarqa groundwater basins, Jordan

    Science.gov (United States)

    Goode, Daniel J.; Senior, Lisa A.; Subah, Ali; Jaber, Ayman

    2013-01-01

    Changes in groundwater levels and salinity in six groundwater basins in Jordan were characterized by using linear trends fit to well-monitoring data collected from 1960 to early 2011. On the basis of data for 117 wells, groundwater levels in the six basins were declining, on average about -1 meter per year (m/yr), in 2010. The highest average rate of decline, -1.9 m/yr, occurred in the Jordan Side Valleys basin, and on average no decline occurred in the Hammad basin. The highest rate of decline for an individual well was -9 m/yr. Aquifer saturated thickness, a measure of water storage, was forecast for year 2030 by using linear extrapolation of the groundwater-level trend in 2010. From 30 to 40 percent of the saturated thickness, on average, was forecast to be depleted by 2030. Five percent of the wells evaluated were forecast to have zero saturated thickness by 2030. Electrical conductivity was used as a surrogate for salinity (total dissolved solids). Salinity trends in groundwater were much more variable and less linear than groundwater-level trends. The long-term linear salinity trend at most of the 205 wells evaluated was not increasing, although salinity trends are increasing in some areas. The salinity in about 58 percent of the wells in the Amman-Zarqa basin was substantially increasing, and the salinity in Hammad basin showed a long-term increasing trend. Salinity increases were not always observed in areas with groundwater-level declines. The highest rates of salinity increase were observed in regional discharge areas near groundwater pumping centers.

  8. Vulnerability of topography-limited and recharge-limited groundwater systems to sea-level rise-induced salinization

    Science.gov (United States)

    Michael, H. A.; Byron, L. A.; Feinson, L. S.; Voss, C. I.; Russoniello, C. J.

    2012-12-01

    The effects of rising sea level on the hydraulic balance between aquifers and the ocean threaten freshwater resources and aquatic ecosystems along many world coastlines. Understanding both the vulnerability of groundwater systems to these changes and the primary factors that determine the magnitude of system response is critical to developing effective management plans in coastal zones. The rate and magnitude of salinization of fresh groundwater due to lateral seawater intrusion and changes in groundwater flow to the sea were assessed over a range of hydrogeologic settings. A primary factor affecting vulnerability is whether the system is recharge-limited or topography-limited. Results of two-dimensional variable-density groundwater-flow and salt-transport simulations indicate that the response of recharge-limited systems is largely minimal, whereas topography-limited systems are vulnerable for various combinations of permeability, vertical anisotropy in permeability, and recharge. World coastlines were classified according to system type as a vulnerability indicator. Results indicate that more than 50 percent of world coastlines are topography-limited over the range of cases tested. Central coastal Bangladesh is an example of a primarily topography-limited system that is highly vulnerable to impacts of sea-level rise as a result of its low elevation, dense population, and extensive groundwater use. Complexities of geologic heterogeneity and salinization processes, including storm-surge overtopping and accelerated salinization rates due to pumping, were considered. Results indicate that geologic heterogeneity has a strong control on the current and evolving pattern of salinity. The process of lateral intrusion can be slow, such that the current salinity distribution may still be changing in response to past sea-level rise. Vertical intrusion from above, where it occurs, is faster, and pumping can accelerate both mechanisms. Bangladesh vulnerability analyses are

  9. GROUNDWATER FLOW MODEL CALIBRATION USING WATER LEVEL MEASUREMENTS AT SHORT INTERVALS

    Science.gov (United States)

    Groundwater flow models are usually calibrated with respect to water level measurements collected at intervals of several months or even years. Measurements of these kinds are not sensitive to sudden or short stress conditions, such as impact from stormwater drainage flow or flas...

  10. Response of surface and groundwater on meteorological drought in Topla River catchment, Slovakia

    Science.gov (United States)

    Fendekova, Miriam; Fendek, Marian; Vrablikova, Dana; Blaskovicova, Lotta; Slivova, Valeria; Horvat, Oliver

    2016-04-01

    Continuously increasing number of drought studies published in scientific journals reflects the attention of the scientific community paid to drought. The fundamental works among many others were published by Yevjevich (1967), Zelenhasic and Salvai (1987), later by Tallaksen and van Lanen Eds. (2004). The aim of the paper was to analyze the response of surface and groundwater to meteorological drought occurrence in the upper and middle part of the Topla River Basin, Slovakia. This catchment belongs to catchments with unfavourable hydrogeological conditions, being built of rocks with quite low permeability. The basin is located in the north-eastern part of Slovakia covering the area of 1050.05 km2. The response was analyzed using precipitation data from the Bardejov station (long-term annual average of 662 mm in 1981 - 2012) and discharge data from two gauging stations - Bardejov and Hanusovce nad Toplou. Data on groundwater head from eight observation wells, located in the catchment, were also used, covering the same observation period. Meteorological drought was estimated using characterisation of the year humidity and SPI index. Hydrological drought was evaluated using the threshold level method and method of sequent peak algorithm, both with the fixed and also variable thresholds. The centroid method of the cluster analysis with the squared Euclidean distance was used for clustering data according to occurrence of drought periods, lasting for 100 days and more. Results of the SPI index showed very good applicability for drought periods identification in the basin. The most pronounced dry periods occurred in 1982 - 1983, 1984, 1998 and 2012 being classified as moderately dry, and also in 1993 - 1994, 2003 - 2004 and 2007 evolving from moderately to severely dry years. Short-term drought prevailed in discharges, only three periods of drought longer than 100 days occurred during the evaluated period in 1986 - 1987, 1997 and 2003 - 2004. Discharge drought in the

  11. THE STUDY OF CHANGES IN ARDABIL PLAIN GROUNDWATER LEVEL USING GIS

    Directory of Open Access Journals (Sweden)

    Javad Zare Aghbolagh

    2016-03-01

    Full Text Available Uncontrolled exploitation of groundwater in many parts of the world has led to a sharp drop in groundwater levels. In this study, changes in Ardabil plain groundwater level were studied using geographic information system (GIS. For this purpose, the interpolation table method was used, the intrinsic data as table data of piezo metric wells was used. In order to implement the model, the Majol Geoestatical in geographic information system software was used. The data entered as regions into the geographic information system, and then done for the entire zoning area, due to zoning 8 models, the IDW, GPI, RBF, LPI, KO, KS, KU and EBK in geostatical extension were evaluated. The ordinary kriging method (KO with the lowest RMSE, was determined as the most accurate one, and finally, as the ultimate method for zoning and map providing for the changes in groundwater levels drop of the region. The results of classification showed that the biggest drop of about 40 meters was in the areas close to the southeastern parts of the study region and in other areas, little changes were observed, this rate of the change and decline in some parts of the desert like southern regions is very tangible and specified.

  12. Precipitation; ground-water age; ground-water nitrate concentrations, 1995-2002; and ground-water levels, 2002-03 in Eastern Bernalillo County, New Mexico

    Science.gov (United States)

    Blanchard, Paul J.

    2004-01-01

    wells during 1995, 1997, and (or) 1998. Nitrate concentrations in two wells were larger than the U.S. Environmental Protection Agency primary drinking-water regulation of 10 milligrams per liter in 1998 and in 2001. Ground-water levels were measured during June and July 2002 and during June, July, and August 2003 in 18 monitoring wells. The median change in water level for all 18 wells was a decline of 2.03 feet.

  13. Perennial filter strips reduce nitrate levels in soil and shallow groundwater after grassland-to-cropland conversion.

    Science.gov (United States)

    Zhou, Xiaobo; Helmers, Matthew J; Asbjornsen, Heidi; Kolka, Randy; Tomer, Mark D

    2010-01-01

    Many croplands planted to perennial grasses under the Conservation Reserve Program are being returned to crop production, and with potential consequences for water quality. The objective of this study was to quantify the impact of grassland-to-cropland conversion on nitrate-nitrogen (NO3-N) concentrations in soil and shallow groundwater and to assess the potential for perennial filter strips (PFS) to mitigate increases in NO3-N levels. The study, conducted at the Neal Smith National Wildlife Refuge (NSNWR) in central Iowa, consisted of a balanced incomplete block design with 12 watersheds and four watershed-scale treatments having different proportions and topographic positions of PFS planted in native prairie grasses: 100% rowcrop, 10% PFS (toeslope position), 10% PFS (distributed on toe and as contour strips), and 20 PFS (distributed on toe and as contour strips). All treatments were established in fall 2006 on watersheds that were under bromegrass (Bromus L.) cover for at least 10 yr. Nonperennial areas were maintained under a no-till 2-yr corn (Zea mays L.)--soybean [Glycine max. (L.) Merr.] rotation since spring 2007. Suction lysimeter and shallow groundwater wells located at upslope and toeslope positions were sampled monthly during the growing season to determine NO3-N concentration from 2005 to 2008. The results indicated significant increases in NO3-N concentration in soil and groundwater following grassland-to-cropland conversion. Nitrate-nitrogen levels in the vadose zone and groundwater under PFS were lower compared with 100% cropland, with the most significant differences occurring at the toeslope position. During the years following conversion, PFS mitigated increases in subsurface nitrate, but long-term monitoring is needed to observe and understand the full response to land-use conversion.

  14. Well-response model of the confined area, Bunker Hill ground-water basin, San Bernardino County, California

    Science.gov (United States)

    Durbin, Timothy J.; Morgan, Charles O.

    1978-01-01

    The Bunker Hill ground-water basin, in the vicinity of San Bernardino, Calif., is being artificially recharged with imported water. Current and future artificial recharge of the basin may cause the potentiometric surface in an area of confined ground water to rise above land surface and water to flow from uncapped and unplugged wells. This could cause damage to structures where the soil becomes waterlogged and where buried wells begin to flow beneath the structures. A well-response model was used to generate a series of water-level hydrographs representing the response of the ground-water basin to six possible combinations of conditions for each well; one pumping rate, two artificial-recharge rate, and three natural-recharge rates. Inflow to the ground-water basin exceeds outflow for all tested combinations. According to model predictions, the accumulation of stored ground water resulting from the excess of inflow is sufficient to cause the water level in the selected wells to rise above land surface for all but one of the combinations of conditions tested. Water levels in wells are predicted to rise above the land surface as early as 1981 for the combination with the greatest excess of inflow. (Woodard-USGS)

  15. Chemical response to groundwater extraction southeast of Mexico City

    Science.gov (United States)

    Huizar-Alvarez, R.; Carrillo-Rivera, J. J.; Ángeles-Serrano, G.; Hergt, T.; Cardona, A.

    An alternative procedure of pumping test data interpretation is used through a joint analysis of the standard time-drawdown curve and simultaneous field measurements of total dissolved solids (TDS); additional support is also provided by the temperature of extracted groundwater and the chemical composition of extracted water. The overall information was applied to characterise the groundwater flow system and its sources, the hydraulic conditions of the aquifer and hydraulic response of extraction boreholes. The analysis of this information suggests the presence of: (i) a local flow system that circulates at shallow depth through basalt units interstratified with fine grained sediments and pyroclastics; these materials contain water with TDS of 127-600 mg/L and Na of 24-178 mg/L, and temperature of 18-19.5 °C (ii) intermediate flow in granular material under reducing conditions by the oxidation of organic matter in aquitard sediments; this water has TDS and Na values of 203-940 and 30-370 mg/L, respectively, and temperatures of about 20-22 °C (iii) regional flow through volcanic rocks and limestone, with TDS content of 300-700 mg/L, Na of 80-230 mg/L and temperature of 23.0-24.8 °C. The hydraulic response and the chemical composition of the water produced by some boreholes are affected by the seepage inflow from sewage effluents, the input from an overlying aquitard unit and the inducement of regional flow. The conception of the flow regime thus obtained allowed the recognition of hydraulic conditions which were more consistent with the hydrogeological setting, than if only a time vs. drawdown test analysis would have been carried out. L'interprétation simultanée de pompages d'essais, des données de température et résidu sec (RS) de L'eau souterraine pompée, mesurées simultanément sur le terrain et la composition chimique de L'eau pompée comme un aide additionnelle, est utilisée comme une différent procédure pour interpréter les pompages d'essais. La

  16. From groundwater abstraction to vegetative response in fen ecosystems

    DEFF Research Database (Denmark)

    Johansen, Ole Munch; Jensen, Jacob Birk; Pedersen, Morten Lauge

    2014-01-01

    periods. The predicted change in water table conditions in the fen habitat is compared to the variability found in 35 Danish fens, and the ecological response is discussed based on statistical water-level vegetation relations. The results provide a rare quantitative foundation for decision making...... resolution. A considerable flow reduction in the natural spring was monitored during a full-scale pumping test while no significant effects on the water table in the fen habitats were observed. A modelled abstraction scenario predicted a lowering of 2–3 cm in the centre of the main fen area during summer...

  17. Screening-Level Risk Assessment for Styrene-Acrylonitrile (SAN) Trimer Detected in Soil and Groundwater

    OpenAIRE

    Kirman, C. R.; Gargas, M L; Collins, J. J.; Rowlands, J. C.

    2012-01-01

    A screening-level risk assessment was conducted for styrene-acrylonitrile (SAN) Trimer detected at the Reich Farm Superfund site in Toms River, NJ. Consistent with a screening-level approach, on-site and off-site exposure scenarios were evaluated using assumptions that are expected to overestimate actual exposures and hazards at the site. Environmental sampling data collected for soil and groundwater were used to estimate exposure point concentrations. Several exposure scenarios were evaluate...

  18. Response of Coastal Groundwater Table to Offshore Storms

    Institute of Scientific and Technical Information of China (English)

    L. Li(李 凌); N. Cartwright; P. Nielsen; D. Lockington

    2004-01-01

    Large groundwater table fluctuations were observed in a coastal aquifer during an offshore storm. The storm induced significant changes of the mean shoreline elevation, characterized by a pulse-like oscillation. This pulse propagated in the aquifer, resulting in the water table fluctuations. A general analytical solution is derived to quantify this new mechanism of water table fluctuation. The solution is applied to field observations and is found to be able to predict reasonably well the observed storm-induced water table fluctuations. Based on the analytical solution, the damping characteristics and phase shift of the oscillation as it propagates inland are exanfined.

  19. Using Hydrologic Data from Africa in a Senior-Level Course in Groundwater Hydrology (Invited)

    Science.gov (United States)

    Silliman, S. E.

    2010-12-01

    Ongoing research efforts in Benin, West Africa, and Uganda, East Africa, have provided substantial data sets involving groundwater quality, applied geophysics, water use, and response of local populations / government agencies to challenges related to water development, protection and management. Ranging from characterization of coastal salt-water encroachment to a major well field to nitrate and microbial contamination of rural water supplies, these data sets were developed by interdisciplinary / international teams that included both undergraduate and graduate students. The present discussion focuses on the integration of the resulting data sets into a senior-level (and lower-level graduate student) course in Groundwater Hydrology. The data sets are employed in multiple ways, including: (i) support of concepts introduced during lectures, (ii) problem sets involving analysis of the data, and (iii) foundation material for open-ended discussions on comparative water resource strategies in developed and developing countries. Most significant in terms of the use of these data sets to advance educational opportunities, the African case studies have been integrated into semester-long projects completed by teams of students as a significant component of their final grade as well as one of their engineering design experiences used to fulfill ABET requirements. During the 2009-2010 academic year, these data sets (as well as published data bases by other agencies) were used by individual groups to design water development strategies for rural villages. During the present semester, two teams of students are pursuing long-term sustainability analyses, the first focused on an aquifer system in northern Indiana (USA) and the second focused on a coastal aquifer system serving Cotonou, Benin. The goal of pursuing these parallel projects is to illustrate to the students the similarities and differences involved in water resource management / protection in different parts of the

  20. Statistical analysis of interaction between lake seepage rates and groundwater and lake levels

    Science.gov (United States)

    Ala-aho, P.; Rossi, P. M.; Klöve, B.

    2012-04-01

    In Finland, the main sources of groundwater are the esker deposits from the last ice age. Small lakes imbedded in the aquifer with no outlets or inlets are typically found in eskers. Some lakes at Rokua esker, in Northern Finland, have been suffering from changes in water stage and quality. A possible permanent decline of water level has raised considerable concern as the area is also used for recreation and tourism. Rare biotypes supported by the oligotrophic lakes can also be endangered by the level decline. Drainage of peatlands located in the discharge zone of the aquifer is a possible threat for the lakes and the whole aquifer. Drainage can potentially lower the aquifer water table which can have an effect on the groundwater-lake interaction. The aim of this study was to understand in more detail the interaction of the aquifer and the lake systems so potential causes for the lake level variations could be better understood and managed. In-depth understanding of hydrogeological system provides foundation to study the nutrient input to lakes affecting lake ecosystems. A small lake imbedded the Rokua esker aquifer was studied in detail. Direct measurements of seepage rate between the lake and the aquifer were carried out using seepage meters. Seepage was measured from six locations for eight times during May 2010 - November 2010. Precipitation was recorded with a tipping bucket rain gauge adjacent to the lake. Lake stage and groundwater levels from three piezometers were registered on an hourly interval using pressure probes. Statistical methods were applied to examine relationship between seepage measurements and levels of lake and groundwater and amount of precipitation. Distinct areas of inseepage and outseepage of the lake were distinguished with seepage meter measurements. Seepage rates showed only little variation within individual measurement locations. Nevertheless analysis revealed statistically significant correlation of seepage rate variation in four

  1. Electricity for groundwater use: constraints and opportunities for adaptive response to climate change

    Science.gov (United States)

    Scott, Christopher A.

    2013-09-01

    Globally, groundwater use is intensifying to meet demands for irrigation, urban supply, industrialization, and, in some instances, electrical power generation. In response to hydroclimatic variability, surface water is being substituted with groundwater, which must be viewed as a strategic resource for climate adaptation. In this sense, the supply of electricity for pumping is an adaptation policy tool. Additionally, planning for climate-change mitigation must consider CO2 emissions resulting from pumping. This paper examines the influence of electricity supply and pricing on groundwater irrigation and resulting emissions, with specific reference to Mexico—a climate-water-energy ‘perfect storm’. Night-time power supply at tariffs below the already-subsidized rates for agricultural groundwater use has caused Mexican farmers to increase pumping, reversing important water and electricity conservation gains achieved. Indiscriminate groundwater pumping, including for virtual water exports of agricultural produce, threatens the long-term sustainability of aquifers, non-agricultural water uses, and stream-aquifer interactions that sustain riparian ecosystems. Emissions resulting from agricultural groundwater pumping in Mexico are estimated to be 3.6% of total national emissions and are equivalent to emissions from transporting the same agricultural produce to market. The paper concludes with an assessment of energy, water, and climate trends coupled with policy futures to address these challenges.

  2. Effects of Groundwater Levels on Photosynthetic Pigments and Light Response of Chlorophyll Fluorescence Parameters of Populus euphratica and Populus pruinosa%地下水位对胡杨(Populus euphratica)和灰胡杨(Populus pruinosa)叶绿素荧光光响应与光合色素含量的影响

    Institute of Scientific and Technical Information of China (English)

    王海珍; 陈加利; 韩路; 徐雅丽; 贾文锁

    2013-01-01

    Photosynthetic pigments and light response curves of chlorophyll fluorescence parameters in leaves of Populus euphratica and Poulus pruinosa,living with different groundwater depths (2.5 m,3.5 m and 5.0 m) in the upper reaches of Tarmi River,were measured with a portable fluorometer.The results showed that chlorophyll fluorescence parameters of light response curves of P.euphratica and P.pruinosa,such as photosynthetic electron transport rate(ETR),non-photochemical quenching(NPQ),excitation pressure (1-qP),the ratio of antenna thermal dissipation (D),excess excited energy(E),relative limitation of photosynthesis(PED),the deviation from full balance between PSⅠ and PS Ⅱ (β/α-1) increased with increasing photosynthetic active radiation(PAR),but PS Ⅱ actual photochemical efficiency(ΦPSⅡ),photochemistry quenching (qP) and the ratio of absorbed light in photochemistry(P) decreased with increasing PAR under different groundwater levels in arid desert environment.The decrease of groundwater levels led to decrease in leaf water content,maximum electron transport rate (ETRmax),initial slope rate of photochemical reaction(θ),ETR,ΦSⅡ,qP,P and leaf content of chlorophyll a (Chla),leaf content of chlorophyll b (Chlb),total chlorophyll (Chla + Chlb),carotenoids,but it led to increase obviously in the ratio of Chla to Chlb (Chla/ Chlb),NPQ,D,E,PED,1-qP,β/α-1 under the same light intensity.The decrease of groundwater levels influenced significantly the chlorophyll fluorescence parameters of light response curves of two tree species,and it led to changes in light energy absorption,transfer and allocation,further to decrease the photosynthetic efficiency.Greater decreases occurred with the deeper groundwater level and P.pruinosa declined more than P.euphratica,it showed P.euphratica were better ecological adaptation to desert environment than P.pruinosa.P.euphratica could maintain relative high ETR,ETRmax,θ,ΦPSⅡ,qP,P and enhanced radiationless energy dissipation

  3. Groundwater level and nitrate concentration trends on Mountain Home Air Force Base, southwestern Idaho

    Science.gov (United States)

    Williams, Marshall L.

    2014-01-01

    Mountain Home Air Force Base in southwestern Idaho draws most of its drinking water from the regional aquifer. The base is located within the State of Idaho's Mountain Home Groundwater Management Area and is adjacent to the State's Cinder Cone Butte Critical Groundwater Area. Both areas were established by the Idaho Department of Water Resources in the early 1980s because of declining water levels in the regional aquifer. The base also is listed by the Idaho Department of Environmental Quality as a nitrate priority area. The U.S. Geological Survey, in cooperation with the U.S. Air Force, began monitoring wells on the base in 1985, and currently monitors 25 wells for water levels and 17 wells for water quality, primarily nutrients. This report provides a summary of water-level and nitrate concentration data collected primarily between 2001 and 2013 and examines trends in those data. A Regional Kendall Test was run to combine results from all wells to determine an overall regional trend in water level. Groundwater levels declined at an average rate of about 1.08 feet per year. Nitrate concentration trends show that 3 wells (18 percent) are increasing in nitrate concentration trend, 3 wells (18 percent) show a decreasing nitrate concentration trend, and 11 wells (64 percent) show no nitrate concentration trend. Six wells (35 percent) currently exceed the U.S. Environmental Protection Agency's maximum contaminant limit of 10 milligrams per liter for nitrate (nitrite plus nitrate, measured as nitrogen).

  4. Groundwater geochemistry near the storage sites of low-level radioactive waste: Implications for uranium migration

    Energy Technology Data Exchange (ETDEWEB)

    Gaskova, Olga L.; Boguslavsky, Anatoly E. [Institute of Geology and Mineralogy SB RAS, Ac. Koptyug prosp. 3, Novosibirsk 630090 (Russian Federation)

    2013-07-01

    This paper presents results of detailed sampling of groundwater and surface water near the storage sites of radioactive waste from the Electrochemical Plant ECP (Zelenogorsk, Krasnoyarsk region, Russia) and the Angarsk Electrolysis Chemical Complex AEC (Angarsk, Irkutsk region, Russia), both of which have produced enriched uranium since 1960's. The liquid (LRW) and solid (SRW) radioactive wastes belong to the category of low-level activity waste. The main result is that the uranium is below the recommended MPC for drinking waters in all types of groundwater around the sludge of ECP and AEC. But alkaline nitrate solutions have been penetrating and spreading into the aquifers under the LRW sludge pits. According to our calculations, redox conditions in the groundwater influenced by discharge are controlled by the couple NO{sub 3}{sup -}/NO{sub 2}{sup -} that facilitates U(VI) migration. The groundwater under SRW repositories is distinguished by its low mineralization and neutral pH. Co-contaminants, such as Mo, V, and Zr may serve as markers of techno-genous contamination in storage sites of the LRW sludge. (authors)

  5. Climate change impact on groundwater levels in the Guarani Aquifer outcrop zone

    Science.gov (United States)

    Melo, D. D.; Wendland, E.

    2013-12-01

    The unsustainable use of groundwater in many countries might cause water availability restrictions in the future. Such issue is likely to worsen due to predicted climate changes for the incoming decades. As numerous studies suggest, aquifers recharge rates will be affected as a result of climate change. The Guarani Aquifer System (GAS) is one of the most important transboundary aquifer in the world, providing drinkable water for millions of people in four South American countries (Brazil, Argentina, Uruguay and Paraguay). Considering the GAS relevance and how its recharge rates might be altered by climatic conditions anomalies, the objective of this work is to assess possible climate changes impacts on groundwater levels in this aquifer outcrop zone. Global Climate Models' (GCM) outputs were used as inputs in a transient flux groundwater model created using the software SPA (Simulation of Process in Aquifers), enabling groundwater table fluctuation to be evaluated under distinct climatic scenarios. Six monitoring wells, located in a representative basin (Ribeirão da Onça basin) inside a GAS outcrop zone (ROB), provided water table measurements between 2004 and 2011 to calibrate the groundwater model. Using observed climatic data, a water budget method was applied to estimate recharge in different types of land uses. Statistically downscaled future climate scenarios were used as inputs for that same recharge model, which provided data for running SPA under those scenarios. The results show that most of the GCMs used here predict temperature arises over 275,15 K and major monthly rainfall mean changes to take place in the dry season. During wet seasons, those means might experience around 50% decrease. The transient model results indicate that water table variations, derived from around 70% of the climate scenarios, would vary below those measured between 2004 and 2011. Among the thirteen GCMs considered in this work, only four of them predicted more extreme

  6. A Comparison of Groundwater Storage Using GRACE Data, Groundwater Levels, and a Hydrological Model in Californias Central Valley

    Science.gov (United States)

    Kuss, Amber; Brandt, William; Randall, Joshua; Floyd, Bridget; Bourai, Abdelwahab; Newcomer, Michelle; Skiles, Joseph; Schmidt, Cindy

    2011-01-01

    The Gravity Recovery and Climate Experiment (GRACE) measures changes in total water storage (TWS) remotely, and may provide additional insight to the use of well-based data in California's agriculturally productive Central Valley region. Under current California law, well owners are not required to report groundwater extraction rates, making estimation of total groundwater extraction difficult. As a result, other groundwater change detection techniques may prove useful. From October 2002 to September 2009, GRACE was used to map changes in TWS for the three hydrological regions (the Sacramento River Basin, the San Joaquin River Basin, and the Tulare Lake Basin) encompassing the Central Valley aquifer. Net groundwater storage changes were calculated from the changes in TWS for each of the three hydrological regions and by incorporating estimates for additional components of the hydrological budget including precipitation, evapotranspiration, soil moisture, snow pack, and surface water storage. The calculated changes in groundwater storage were then compared to simulated values from the California Department of Water Resource's Central Valley Groundwater- Surface Water Simulation Model (C2VSIM) and their Water Data Library (WDL) Geographic Information System (GIS) change in storage tool. The results from the three methods were compared. Downscaling GRACE data into the 21 smaller Central Valley sub-regions included in C2VSIM was also evaluated. This work has the potential to improve California's groundwater resource management and use of existing hydrological models for the Central Valley.

  7. Forecasting monthly groundwater level fluctuations in coastal aquifers using hybrid Wavelet packet–Support vector regression

    Directory of Open Access Journals (Sweden)

    N. Sujay Raghavendra

    2015-12-01

    Full Text Available This research demonstrates the state-of-the-art capability of Wavelet packet analysis in improving the forecasting efficiency of Support vector regression (SVR through the development of a novel hybrid Wavelet packet–Support vector regression (WP–SVR model for forecasting monthly groundwater level fluctuations observed in three shallow unconfined coastal aquifers. The Sequential Minimal Optimization Algorithm-based SVR model is also employed for comparative study with WP–SVR model. The input variables used for modeling were monthly time series of total rainfall, average temperature, mean tide level, and past groundwater level observations recorded during the period 1996–2006 at three observation wells located near Mangalore, India. The Radial Basis function is employed as a kernel function during SVR modeling. Model parameters are calibrated using the first seven years of data, and the remaining three years data are used for model validation using various input combinations. The performance of both the SVR and WP–SVR models is assessed using different statistical indices. From the comparative result analysis of the developed models, it can be seen that WP–SVR model outperforms the classic SVR model in predicting groundwater levels at all the three well locations (e.g. NRMSE(WP–SVR = 7.14, NRMSE(SVR = 12.27; NSE(WP–SVR = 0.91, NSE(SVR = 0.8 during the test phase with respect to well location at Surathkal. Therefore, using the WP–SVR model is highly acceptable for modeling and forecasting of groundwater level fluctuations.

  8. Variations of dominant microbial populations in groundwater in response to the leachate from Laogang Landfill

    Institute of Scientific and Technical Information of China (English)

    TIAN Yang-jie; YANG Hong; LI Dao-tang; LIN Zhi-xin

    2005-01-01

    Temporal changes of dominant microbial populations in groundwater in response to the leachate from Shanghai Laogang Landfill were investigated. Concentrations of dissolved redox-relevant species in groundwater suggested that the dominating redox process had changed from denitrification to methane-production/sulfate-reduction due to landfilling. Dominant microbial populations were determined using restriction fragment length polymorphism(RFLP) analyses of 16S rRNA gene libraries, which were further studied by sequencing and phylogenetic analyses. The results indicated that obvious shifts of dominant microbial populations had occurred in groundwater in response to the pollution of leachate. The closest relatives of some dominant clones are accordant with the dominating redox processes determined by hydrochemical analyses, based on the GenBank's indications on the ability to perform redox reactions.

  9. Effects on the groundwater levels of the May-June 2012 Emilia seismic sequence

    Directory of Open Access Journals (Sweden)

    Marco Marcaccio

    2012-10-01

    Full Text Available A variety of phenomena were observed in the groundwaters in concomitance with the May-June 2012 seismic sequence that occurred in the Emilia Romagna area. In particular, phreatic wells close to the epicentral area were affected by a sudden increase in water level of up to 4 m. In some cases, the sands of aquifers were ejected outside wells, and >700 liquefaction phenomena were recorded [Bertolini and Fioroni 2012, this volume]. Some automatic stations of the regional well network recorded variations in well levels. These data can be considered useful to understand the relationships between seismic events and the local groundwaters [see also Italiano et al. 2012, this volume]. […] In 1976, a regional network composed of 330 wells was set up with the purpose of monitoring the groundwater levels using manual techniques. These data have been used for environmental purposes and for water management. In recent years, the monitoring network managed by Agenzia Regionale Prevenzione e Ambiente (ARPA has increased the number of wells (to about 600, and chemical analyses are also periodically carried out for environmental monitoring activities. In the past three years, an automatic monitoring network composed of 40 stations was set up and this has allowed the monitoring of the water levels and the temperatures, at a rate of one measure per hour, and to broadcast the data to the host center located in Bologna. […

  10. Recent trends in groundwater levels in a highly seasonal hydrological system: the Ganges-Brahmaputra-Meghna Delta

    Directory of Open Access Journals (Sweden)

    M. Shamsudduha

    2009-12-01

    Full Text Available Groundwater levels in shallow aquifers underlying Asian mega-deltas are characterized by strong seasonal variations associated with monsoon rainfall. To resolve trend and seasonal components in weekly groundwater levels in the Ganges-Brahmaputra-Meghna (GBM Delta, we apply a nonparametric seasonal-trend decomposition procedure (STL to observations compiled from 1985–2005 in Bangladesh. Seasonality dominates observed variance in groundwater levels but declining groundwater levels (>1 m/yr are detected in urban and peri-urban areas around Dhaka as well as in north-central, northwestern, and southwestern parts of the country (0.1–0.5 m/yr where intensive abstraction of groundwater is conducted for dry-season rice cultivation. Rising groundwater levels (0.5–2.5 cm/yr are observed in the estuarine and southern coastal regions. This novel application of the STL procedure reveals, for the first time, the unsustainability of irrigation supplied by shallow aquifers in some areas (e.g., High Barind Tract of the GBM Delta and the hydrological impact of potential seawater intrusion of coastal aquifers associated with sea-level rise. Our findings provide important insight into the hydrological impacts of groundwater-fed irrigation and sea-level rise in other Asian mega-deltas where monitoring data are limited.

  11. Recent trends in groundwater levels in a highly seasonal hydrological system: the Ganges-Brahmaputra-Meghna Delta

    Directory of Open Access Journals (Sweden)

    M. Shamsudduha

    2009-06-01

    Full Text Available Groundwater levels in shallow aquifers underlying Asian mega-deltas are characterized by strong seasonal variations associated with monsoon rainfall. To resolve trend and seasonal components in weekly groundwater levels in the Ganges-Brahmaputra-Meghna (GBM Delta, we apply a nonparametric seasonal-trend decomposition procedure (STL to observations compiled from 1985 to 2005 in Bangladesh. Seasonality dominates observed variance in groundwater levels but declining groundwater levels (>1 m/yr are detected in urban and peri-urban areas around Dhaka as well as in north-central, northwestern, and southwestern parts of the country (0.1 to 0.5 m/yr where intensive abstraction of groundwater is conducted for dry-season rice cultivation. Rising groundwater levels (0.5 to 2.5 cm/yr are observed in the estuarine and southern coastal regions. This novel application of the STL procedure reveals, for the first time, the unsustainability of irrigation supplied by shallow aquifers in some areas of the GBM Delta and the hydrological impact of seawater intrusion of coastal aquifers associated with sea-level rise. Our findings provide important insight into the hydrological impacts of groundwater-fed irrigation and sea-level rise in other Asian mega-deltas where monitoring data are limited.

  12. Mean Transit Time as a Predictor of Groundwater Discharge Response in the Upper Colorado River Basin

    Science.gov (United States)

    Solder, J. E.; Heilweil, V. M.; Stolp, B. J.; Susong, D.

    2015-12-01

    The Colorado River and its tributaries support 40 million municipal water users and 5.5 million acres of agriculture in the south western United States (U.S. Bureau of Reclamation, 2012). Recent estimates by Rumsey et al. (2015) suggest that a significant portion (about 50 percent) of surface water flow in the Upper Colorado River Basin (UCRB) is sustained by groundwater discharge to streams. Predicted climate variation (Cook et al., 2015) and increased water demand (U.S. Bureau of Reclamation, 2012) within the UCRB suggest future decreases in groundwater discharge, however transient groundwater responses are not well understood. In this study we calculate groundwater mean transit time (MTT) and transit time distribution (TTD) as predictors of the pattern and timing of groundwater response to hydraulic stress. Samples from nineteen large springs within the UCRB were analyzed for environmental tracers to determine MTT and TTD. The predictive value of the MTT is examined by a statistical analysis of MTT, historical spring discharge records, and the Palmer Hydrological Drought Index. MTTs of the 19 springs range from 10 to 15,000 years with a flow-weighted average of 1,650 years. The composite TTD of the 19 springs suggest that flowpaths representing 45 percent of their combined discharge have transit times greater than 100 years. However, spring discharge records indicate that flow responds to drought on much shorter (0.5 - 6 year) time scales, indicative of a hydraulic pressure response. Springs with shorter MTTs ( 100) also show a hydraulic pressure response. While not fully representative of the UCRB, results from the 19 springs indicate that groundwater discharge responds to climate variation and water-demand imbalances over a relatively short time period of years.

  13. Analysis of the applicability of geophysical methods and computer modelling in determining groundwater level

    Science.gov (United States)

    Czaja, Klaudia; Matula, Rafal

    2014-05-01

    The paper presents analysis of the possibilities of application geophysical methods to investigation groundwater conditions. In this paper groundwater is defined as liquid water flowing through shallow aquifers. Groundwater conditions are described through the distribution of permeable layers (like sand, gravel, fractured rock) and impermeable or low-permeable layers (like clay, till, solid rock) in the subsurface. GPR (Ground Penetrating Radar), ERT(Electrical Resistivity Tomography), VES (Vertical Electric Soundings) and seismic reflection, refraction and MASW (Multichannel Analysis of Surface Waves) belong to non - invasive, surface, geophysical methods. Due to differences in physical parameters like dielectric constant, resistivity, density and elastic properties for saturated and saturated zones it is possible to use geophysical techniques for groundwater investigations. Few programmes for GPR, ERT, VES and seismic modelling were applied in order to verify and compare results. Models differ in values of physical parameters such as dielectric constant, electrical conductivity, P and S-wave velocity and the density, layers thickness and the depth of occurrence of the groundwater level. Obtained results for computer modelling for GPR and seismic methods and interpretation of test field measurements are presented. In all of this methods vertical resolution is the most important issue in groundwater investigations. This require proper measurement methodology e.g. antennas with frequencies high enough, Wenner array in electrical surveys, proper geometry for seismic studies. Seismic velocities of unconsolidated rocks like sand and gravel are strongly influenced by porosity and water saturation. No influence of water saturation degree on seismic velocities is observed below a value of about 90% water saturation. A further saturation increase leads to a strong increase of P-wave velocity and a slight decrease of S-wave velocity. But in case of few models only the

  14. Influence of seasonal variations in sea level on the salinity regime of a coastal groundwater-fed wetland.

    Science.gov (United States)

    Wood, Cameron; Harrington, Glenn A

    2015-01-01

    Seasonal variations in sea level are often neglected in studies of coastal aquifers; however, they may have important controls on processes such as submarine groundwater discharge, sea water intrusion, and groundwater discharge to coastal springs and wetlands. We investigated seasonal variations in salinity in a groundwater-fed coastal wetland (the RAMSAR listed Piccaninnie Ponds in South Australia) and found that salinity peaked during winter, coincident with seasonal sea level peaks. Closer examination of salinity variations revealed a relationship between changes in sea level and changes in salinity, indicating that sea level-driven movement of the fresh water-sea water interface influences the salinity of discharging groundwater in the wetland. Moreover, the seasonal control of sea level on wetland salinity seems to override the influence of seasonal recharge. A two-dimensional variable density model helped validate this conceptual model of coastal groundwater discharge by showing that fluctuations in groundwater salinity in a coastal aquifer can be driven by a seasonal coastal boundary condition in spite of seasonal recharge/discharge dynamics. Because seasonal variations in sea level and coastal wetlands are ubiquitous throughout the world, these findings have important implications for monitoring and management of coastal groundwater-dependent ecosystems.

  15. Numerical Simulation of Changes in Groundwater-Level Induced by Earthquakes

    Science.gov (United States)

    Liu, Ching-Yi; Chia, Yeeping; Zheng, Ding-Qian

    2016-04-01

    Changes in groundwater level induced by earthquakes have been recorded worldwide. Sustained groundwater-level changes during earthquakes, primarily induced by the co-seismic strain due to fault displacement, are often observed in the confined aquifer. In the unconfined aquifer, sustained co-seismic changes can hardly be observed due to the rapid recovery of pore pressure change. In this study, field observation of co-seismic groundwater-level changes are showed. Also, the finite element software ABAQUS is used to simulate two-dimensional time-dependent pore pressure change in the aquifer due to fault displacement during earthquakes. Different physical properties are used to represent different types of aquifer. We adopted the 3-step method to simulate how earthquakes affect pore pressure in the 3 models, unconfined aquifer, confined aquifer and over-pressured confined layers. Results from the simulation gives us more details of how co-seismic and post-seismic pore pressure temporal changes are processed in different aquifers.

  16. Nitrogen and Oxygen Isotopes of Low-Level Nitrate in Groundwater For Environmental Forensics

    Science.gov (United States)

    Wang, Y.

    2009-05-01

    Sources of nitrate in water from human activities include fertilizers, animal feedlots, septic systems, wastewater treatment lagoons, animal wastes, industrial wastes and food processing wastes. Nitrogen and Oxygen isotopic analysis of nitrate in groundwater is essential to source identification and environmental forensics as nitrate from different sources carry distinctly different N and O isotopic compositions. Nitrate is extracted from groundwater samples and converted into AgNO3 using ion exchange techniques. The purified AgNO3 is then broken down into N2 and CO for N and O isotopic measurement. Since nitrate concentrations in natural ground waters are usually less than 2 mg/L, however, such method has been limited by minimum sample size it requires, in liters, which is highly nitrate concentration dependent. Here we report a TurboVap- Denitrifier method for N and O isotopic measurement of low-level dissolved nitrate, based on sample evaporation and isotopic analysis of nitrous oxide generated from nitrate by denitrifying bacteria that lack N2O- reductase activity. For most groundwater samples with mg/L-level of nitrate direct injection of water samples in mLs is applied. The volume of sample is adjusted according to its nitrate concentration to achieve a final sample size optimal for the system. For water samples with ug/L-level of nitrate, nitrate is highly concentrated using a TurboVap evaporator, followed by isotopic measurement with Denitrifier method. Benefits of TurboVap- Denitrifier method include high sensitivity and better precision in both isotopic data. This method applies to both freshwater and seawater. The analyses of isotopic reference materials in nitrate-free de-ionized water and seawater are included as method controls to correct for any blank effects. The isotopic data from groundwater and ocean profiles demonstrate the consistency of the data produced by the TurboVap-Denitrifier method.

  17. Comparison of stochastic and deterministic methods for mapping groundwater level spatial variability in sparsely monitored basins.

    Science.gov (United States)

    Varouchakis, Epsilon A; Hristopulos, D T

    2013-01-01

    In sparsely monitored basins, accurate mapping of the spatial variability of groundwater level requires the interpolation of scattered data. This paper presents a comparison of deterministic interpolation methods, i.e. inverse distance weight (IDW) and minimum curvature (MC), with stochastic methods, i.e. ordinary kriging (OK), universal kriging (UK) and kriging with Delaunay triangulation (DK). The study area is the Mires Basin of Mesara Valley in Crete (Greece). This sparsely sampled basin has limited groundwater resources which are vital for the island's economy; spatial variations of the groundwater level are important for developing management and monitoring strategies. We evaluate the performance of the interpolation methods with respect to different statistical measures. The Spartan variogram family is applied for the first time to hydrological data and is shown to be optimal with respect to stochastic interpolation of this dataset. The three stochastic methods (OK, DK and UK) perform overall better than the deterministic counterparts (IDW and MC). DK, which is herein for the first time applied to hydrological data, yields the most accurate cross-validation estimate for the lowest value in the dataset. OK and UK lead to smooth isolevel contours, whilst DK and IDW generate more edges. The stochastic methods deliver estimates of prediction uncertainty which becomes highest near the southeastern border of the basin.

  18. COVARIANCE CORRECTION FOR ESTIMATING GROUNDWATER LEVEL USING DETERMINISTIC ENSEMBLE KALMAN FILTER

    Directory of Open Access Journals (Sweden)

    J. Behmanesh

    2015-01-01

    Full Text Available The main problem in developing a groundwater model is to determine model parameters, particularly hydrogeologic coefficients, in a precise way. In this research, Deterministic Ensemble Kalman Filter (DEnKF is described as a modern sequential method for data assimilation and a localization scheme within the framework of DEnKF is applied. Najafabad aquifer (in Iran with area of 1150 km2, is modeled in the time window of Oct. 2000 to Sept. 2007 to obtain water table level data when its values of hydrogeologic coefficients calibrated and verified. DEnKF assimilated 45 observations of true run into the model with 2, 5, and 10 times of calibrated values of hydraulic conductivity and specific yield. This filter has been run both with and without use of localization. Results show easily-implemented localized DEnKF is favorably robust in groundwater flow modeling.

  19. A new approach for estimating groundwater table fluctuation response to rainfall events in North China Plain

    Science.gov (United States)

    Liao, Z.; Xie, X.; Ma, Z.

    2015-12-01

    A rise or decline in water table in response to water budget is a function of rainfall volume and groundwater depletion intensity. Most research have focus on estimating water table fluctuations among various shallow aquifer resulting from recharge and discharge change, however, the methods commonly applied are limited in that the subsurface system is more complex. In this paper, a reliable approach based on statistics theory is presented for quantifying the correlation relationship among water table, rainfall events and groundwater depletion process. The detail monitoring data are used to multivariate regression analysis and established the relationship model between water table and groundwater depletion in the proposed method. We further employed the model to obtain water table fluctuation trend with manual controlled depletion in different rainfall conditions. We also identify how this model applied to North China Plain and examine the water table error. The results show that controlling the depletion process based on different rainfall frequency can promote groundwater table recover and the model can provide a reliable method to groundwater management.

  20. Rational allocation of water resources based on ecological groundwater levels:a case study in Jinghui Irrigation District in China

    Science.gov (United States)

    Li, H.; Zhou, W. B.; Dong, Q. G.; Liu, B. Y.; Ma, C.

    2016-08-01

    Aimed at the hydrogeological environmental problems caused by over-exploitation and unreasonable utilization of water resources in Jinghui Irrigation District, this paper discusses the ecological groundwater level of the study area and establishes a three-layer optimal allocation model of water resources based on the theory of large scale systems. Then, the genetic algorithm method was employed to optimize the model and obtain the optimal allocation of crop irrigation schedule and water resources under the condition of a 75% assurance rate. Finally, the numerical simulation model of the groundwater was applied to analyze the balance of the groundwater on the basis of the optimal allocation scheme. The results show that the upper limitation of the ecological groundwater in Jinghui Irrigation District ranged from 1.8m to 4.2m, while the lower limitation level ranged from 8m to 28m. By 2020, the condition of the groundwater imbalance that results from adopting the optimal allocation scheme will be much better than that caused by current water utilization scheme. With the exception of only a few areas, the groundwater level in most parts of Jinghui Irrigation District will not exceed the lower limitation of ecological groundwater level.

  1. Modelling the distribution of tritium in groundwater across South Africa to assess the vulnerability and sustainability of groundwater resources in response to climate change

    Science.gov (United States)

    van Rooyen, Jared; Miller, Jodie; Watson, Andrew; Butler, Mike

    2017-04-01

    Groundwater is critical for sustaining human populations, especially in semi-arid to arid areas, where surface water availability is low. Shallow groundwater is usually abstracted for this purpose because it is the easiest to access and assumed to be renewable and regularly recharged by precipitation. Renewable, regularly recharged groundwater is also called modern groundwater, ie groundwater that has recently been in contact with the atmosphere. Tritium can be used to determine whether or not a groundwater resource is modern because the half-life of tritium is only 12.36 years and tritium is dominantly produced in the upper atmosphere and not in the rock mass. For this reason, groundwater with detectable tritium activities likely has a residence age of less than 50 years. In this study, tritium activities in 277 boreholes distributed across South Africa were used to develop a national model for tritium activity in groundwater in order to establish the extent of modern groundwater across South Africa. The tritium model was combined with modelled depth to water using 3079 measured static water levels obtained from the National Groundwater Archive and validated against a separate set of 40 tritium activities along the west coast of South Africa. The model showed good agreement with the distribution of rainfall which has been previously documented across the globe (Gleeson et al., 2015), although the arid Karoo basin in south west South Africa shows higher than expected tritium levels given the very low regional precipitation levels. To assess the vulnerability of groundwater to degradation in quality and quantity, the tritium model was incorporated into a multi-criteria evaluation (MCE) model which incorporated other indicators of groundwater stress including mean annual precipitation, mean annual surface temperature, electrical conductivity (as a proxy for groundwater salinization), potential evaporation, population density and cultivated land usage. The MCE model

  2. Comparison of different methods to assess natural backgrond levels in groundwater bodies in southern Europe

    Science.gov (United States)

    Preziosi, Elisabetta; Parrone, Daniele; Ghergo, Stefano; Ducci, Daniela; Sellerino, Mariangela; Condesso de Melo, Maria Teresa; Oliveira, Juana; Ribeiro, Luis

    2014-05-01

    The assessment of the natural background levels (NBLs) of a substance or element is important to distinguish anthropogenic pollution from contamination of natural origin in groundwater bodies. NBLs are the result of different atmospheric, geological, chemical and biological interaction processes during groundwater infiltration and circulation. Rainfall composition, water-rock interactions in both vadose and saturated zone, exchanges with other water bodies and residence time also contribute to determine the groundwater natural composition. Nowadays there are different methods to assess NBLs but the main concern is that they may provide different results. In the European legislative context, the Groundwater Directive (2006/118/EC) requests to EU Member States to derive appropriate threshold values (TV) for several potentially harmful substances, taking into account NBLs when necessary, in order to assess the chemical status of groundwater bodies. In the framework of a common project between Italy (CNR) and Portugal (FCT), several groundwater bodies were taken into account in different regions of Italy (Latium and Campania) and Portugal. The general objective is the definition of a sound comprehensive methodology for NBL assessment at groundwater body scale, suitable to different hydrogeological settings through comparing diverse case studies and different approaches. The Italian case studies are located in volcanic or volcano-sedimentary geological contexts, where high concentrations of substances such as As, F, Fe, Mn among others in groundwater are well known. The Portuguese case studies are located in carbonate and porous media aquifers. Several data sets were explored with the use of statistical as well as mathematical procedures in order to determine a threshold between natural and anthropogenic concentration. Today essentially two groups of methods are proposed, the first ascribed to the probability plots (PP method), the second based on the selection of the

  3. Behavioral response to contamination risk information in a spatially explicit groundwater environment: Experimental evidence

    Science.gov (United States)

    Li, Jingyuan; Michael, Holly A.; Duke, Joshua M.; Messer, Kent D.; Suter, Jordan F.

    2014-08-01

    This paper assesses the effectiveness of aquifer monitoring information in achieving more sustainable use of a groundwater resource in the absence of management policy. Groundwater user behavior in the face of an irreversible contamination threat is studied by applying methods of experimental economics to scenarios that combine a physics-based, spatially explicit, numerical groundwater model with different representations of information about an aquifer and its risk of contamination. The results suggest that the threat of catastrophic contamination affects pumping decisions: pumping is significantly reduced in experiments where contamination is possible compared to those where pumping cost is the only factor discouraging groundwater use. The level of information about the state of the aquifer also affects extraction behavior. Pumping rates differ when information that synthesizes data on aquifer conditions (a "risk gauge") is provided, despite invariant underlying economic incentives, and this result does not depend on whether the risk information is location-specific or from a whole aquifer perspective. Interestingly, users increase pumping when the risk gauge signals good aquifer status compared to a no-gauge treatment. When the gauge suggests impending contamination, however, pumping declines significantly, resulting in a lower probability of contamination. The study suggests that providing relatively simple aquifer condition guidance derived from monitoring data can lead to more sustainable use of groundwater resources.

  4. Natural radioactivity levels in granitic plutons and groundwaters in Southeast part of Eskisehir, Turkey.

    Science.gov (United States)

    Orgün, Y; Altinsoy, N; Gültekin, A H; Karahan, G; Celebi, N

    2005-08-01

    The present work investigated the radioactivity level of the granitoid plutons and its effect on the groundwaters in the southeast part of Eskisehir. Fourteen granitic samples from the Kaymaz and Sivrihisar plutons and 11 groundwater samples from the near vicinity of the pluton were analyzed. The activity concentrations measured for (238)U and (232)Th ranged from 43.59+/-2 to 651.80+/-24 Bq/kg, and 51.16+/-3 to 351.94+/-13 Bq/kg, respectively. The activity concentrations obtained for (40)K varied from 418.50+/-17 to 1618.03+/-66 Bq/kg. The absorbed dose rates in air outdoors ranged from 87.14 to 531.81 nGy/h. All the results obtained from the Kaymaz pluton are higher than those from the Sivrihisar. The U (ave. 16.6 ppm) and Th (ave. 49.9 ppm) values of the Kaymaz pluton are higher than the average concentrations of the magmatic rocks of granitic composition. These results are consistent with high dose rates of the pluton. The gross-alpha activities in the groundwater samples ranged from 0.009 to 1.64 Bq/l and the gross-beta activities from 0.006 to 0.89 Bq/l. The highest gross-alpha value was found in the sample taken from near the Kaymaz pluton. The concentrations of (222)Rn varied from 0.060 to 0.557 Bq/l.

  5. Research on critical groundwater level under the threshold value of land subsidence in the typical region of Beijing

    Science.gov (United States)

    Jiang, Y.; Liu, J.-R.; Luo, Y.; Yang, Y.; Tian, F.; Lei, K.-C.

    2015-11-01

    Groundwater in Beijing has been excessively exploited in a long time, causing the groundwater level continued to declining and land subsidence areas expanding, which restrained the economic and social sustainable development. Long years of study show good time-space corresponding relationship between groundwater level and land subsidence. To providing scientific basis for the following land subsidence prevention and treatment, quantitative research between groundwater level and settlement is necessary. Multi-linear regression models are set up by long series factual monitoring data about layered water table and settlement in the Tianzhu monitoring station. The results show that: layered settlement is closely related to water table, water level variation and amplitude, especially the water table. Finally, according to the threshold value in the land subsidence prevention and control plan of China (45, 30, 25 mm), the minimum allowable layered water level in this region while settlement achieving the threshold value is calculated between -18.448 and -10.082 m. The results provide a reasonable and operable control target of groundwater level for rational adjustment of groundwater exploited horizon in the future.

  6. Application of a modified conceptual rainfall-runoff model to simulation of groundwater level in an undefined watershed.

    Science.gov (United States)

    Hong, Nian; Hama, Takehide; Suenaga, Yuichi; Aqili, Sayed Waliullah; Huang, Xiaowu; Wei, Qiaoyan; Kawagoshi, Yasunori

    2016-01-15

    Groundwater level simulation models can help ensure the proper management and use of urban and rural water supply. In this paper, we propose a groundwater level tank model (GLTM) based on a conceptual rainfall-runoff model (tank model) to simulate fluctuations in groundwater level. The variables used in the simulations consist of daily rainfall and daily groundwater level, which were recorded between April 2011 and March 2015 at two representative observation wells in Kumamoto City, Japan. We determined the best-fit model parameters by root-mean-square error through use of the Shuffled Complex Evolution-University of Arizona algorithm on a simulated data set. Calibration and validation results were evaluated by their coefficients of determination, Nash-Sutcliffe efficiency coefficients, and root-mean-square error values. The GLTM provided accurate results in both the calibration and validation of fluctuations in groundwater level. The split sample test results indicate a good reliability. These results indicate that this model can provide a simple approach to the accurate simulation of groundwater levels.

  7. Research on critical groundwater level under the threshold value of land subsidence in the typical region of Beijing

    Directory of Open Access Journals (Sweden)

    Y. Jiang

    2015-11-01

    Full Text Available Groundwater in Beijing has been excessively exploited in a long time, causing the groundwater level continued to declining and land subsidence areas expanding, which restrained the economic and social sustainable development. Long years of study show good time-space corresponding relationship between groundwater level and land subsidence. To providing scientific basis for the following land subsidence prevention and treatment, quantitative research between groundwater level and settlement is necessary. Multi-linear regression models are set up by long series factual monitoring data about layered water table and settlement in the Tianzhu monitoring station. The results show that: layered settlement is closely related to water table, water level variation and amplitude, especially the water table. Finally, according to the threshold value in the land subsidence prevention and control plan of China (45, 30, 25 mm, the minimum allowable layered water level in this region while settlement achieving the threshold value is calculated between −18.448 and −10.082 m. The results provide a reasonable and operable control target of groundwater level for rational adjustment of groundwater exploited horizon in the future.

  8. Mapping groundwater level and aquifer storage variations from InSAR measurements in the Madrid aquifer, Central Spain

    Science.gov (United States)

    Béjar-Pizarro, Marta; Ezquerro, Pablo; Herrera, Gerardo; Tomás, Roberto; Guardiola-Albert, Carolina; Ruiz Hernández, José M.; Fernández Merodo, José A.; Marchamalo, Miguel; Martínez, Rubén

    2017-04-01

    Groundwater resources are under stress in many regions of the world and the future water supply for many populations, particularly in the driest places on Earth, is threatened. Future climatic conditions and population growth are expected to intensify the problem. Understanding the factors that control groundwater storage variation is crucial to mitigate its adverse consequences. In this work, we apply satellite-based measurements of ground deformation over the Tertiary detritic aquifer of Madrid (TDAM), Central Spain, to infer the spatio-temporal evolution of water levels and estimate groundwater storage variations. Specifically, we use Persistent Scatterer Interferometry (PSI) data during the period 1992-2010 and piezometric time series on 19 well sites covering the period 1997-2010 to build groundwater level maps and quantify groundwater storage variations. Our results reveal that groundwater storage loss occurred in two different periods, 1992-1999 and 2005-2010 and was mainly concentrated in a region of ∼200 km2. The presence of more compressible materials in that region combined with a long continuous water extraction can explain this volumetric deficit. This study illustrates how the combination of PSI and piezometric data can be used to detect small aquifers affected by groundwater storage loss helping to improve their sustainable management.

  9. The thermal consequences of river-level variations in an urban groundwater body highly affected by groundwater heat pumps.

    Science.gov (United States)

    García-Gil, Alejandro; Vázquez-Suñe, Enric; Schneider, Eduardo Garrido; Sánchez-Navarro, José Ángel; Mateo-Lázaro, Jesús

    2014-07-01

    The extensive implementation of ground source heat pumps in urban aquifers is an important issue related to groundwater quality and the future economic feasibility of existent geothermal installations. Although many cities are in the immediate vicinity of large rivers, little is known about the thermal river-groundwater interaction at a kilometric-scale. The aim of this work is to evaluate the thermal impact of river water recharges induced by flood events into an urban alluvial aquifer anthropogenically influenced by geothermal exploitations. The present thermal state of an urban aquifer at a regional scale, including 27 groundwater heat pump installations, has been evaluated. The thermal impacts of these installations in the aquifer together with the thermal impacts from "cold" winter floods have also been spatially and temporally evaluated to ensure better geothermal management of the aquifer. The results showed a variable direct thermal impact from 0 to 6 °C depending on the groundwater-surface water interaction along the river trajectory. The thermal plumes far away from the riverbed also present minor indirect thermal impacts due to hydraulic gradient variations. Copyright © 2014 Elsevier B.V. All rights reserved.

  10. Response of the hyporheic zone to transient groundwater fluctuations on the annual and storm event time scales

    Science.gov (United States)

    Malzone, Jonathan M.; Lowry, Christopher S.; Ward, Adam S.

    2016-07-01

    The volume of the water stored in and exchanged with the hyporheic zone is an important factor in stream metabolism and biogeochemical cycling. Previous studies have identified groundwater direction and magnitude as one key control on the volume of the hyporheic zone, suggesting that fluctuation in the riparian water table could induce large changes under certain seasonal conditions. In this study, we analyze the transient drivers that control the volume of the hyporheic zone by coupling the Brinkman-Darcy equation to the Navier-Stokes equations to simulate annual and storm induced groundwater fluctuations. The expansion and contraction of the hyporheic zone was quantified based on temporally dynamic scenarios simulating annual groundwater fluctuations in a humid temperate climate. The amplitude of the groundwater signal was varied between scenarios to represent a range of annual hydrologic forcing. Storm scenarios were then superimposed on the annual scenario to simulate the response to short-term storm signals. Simulations used two different groundwater storm responses; one in-phase with the surface water response and one 14 h out-of-phase with the surface water response to represent our observed site conditions. Results show that annual groundwater fluctuation is a dominant control on the volume of the hyporheic zone, where increasing groundwater fluctuation increases the amount of annual variation. Storm responses depended on the antecedent conditions determined by annual scenarios, where the time of year dictated the duration and magnitude of the storm induced response of the hyporheic zone.

  11. Tide-induced fluctuations of salinity and groundwater level in unconfined aquifers - Field measurements and numerical model

    Science.gov (United States)

    Levanon, Elad; Yechieli, Yoseph; Gvirtzman, Haim; Shalev, Eyal

    2017-08-01

    The responses of the fresh-saline water interface (FSI) and the groundwater level (GWL) to the Mediterranean Sea tide were monitored in the coastal aquifer of Israel, modeled numerically and analyzed using cross-correlation analysis. Different time-lags between sea level fluctuations and hydraulic head and salinity fluctuations were detected for the FSI and the GWL. At the FSI, the time-lag of hydraulic head behind the sea level is much shorter than the lag of the salinity at the same point. Surprisingly, similar time-lags behind the sea level were measured for both the hydraulic head at the GWL and the salinity at the FSI, both at the same distance from the shoreline. Results from a numerical model, simulating the flow and transport processes at the field scale, agree with field measurements. In both, the GWL and the salinity in the FSI fluctuate almost simultaneously, while the hydraulic head in the FSI reacts faster to sea level fluctuations. The actual movement of the fresh water body, which is controlled by the unsaturated flow in the capillary fringe ('capillary effect'), lags behind the pressure head fluctuations in the deeper parts of the aquifer, which is controlled by saturated parameters of the aquifer. The overall results agree with the conceptual mechanism suggested by Levanon et al. (2016), in which the effect of sea tide on the coastal groundwater system comprises two main processes: (1) tidal fluctuations at the sea floor boundary which cause pressure wave propagation into the aquifer, and (2) attenuation at the GWL due to the capillary effect which control also the change in the salinity and the actual movement of the FSI.

  12. Effects of Heterogeneity and Uncertainties in Sources and Initial and Boundary Conditions on Spatiotemporal Variations of Groundwater Levels

    Science.gov (United States)

    Zhang, Y. K.; Liang, X.

    2014-12-01

    Effects of aquifer heterogeneity and uncertainties in source/sink, and initial and boundary conditions in a groundwater flow model on the spatiotemporal variations of groundwater level, h(x,t), were investigated. Analytical solutions for the variance and covariance of h(x, t) in an unconfined aquifer described by a linearized Boussinesq equation with a white noise source/sink and a random transmissivity field were derived. It was found that in a typical aquifer the error in h(x,t) in early time is mainly caused by the random initial condition and the error reduces as time goes to reach a constant error in later time. The duration during which the effect of the random initial condition is significant may last a few hundred days in most aquifers. The constant error in groundwater in later time is due to the combined effects of the uncertain source/sink and flux boundary: the closer to the flux boundary, the larger the error. The error caused by the uncertain head boundary is limited in a narrow zone near the boundary but it remains more or less constant over time. The effect of the heterogeneity is to increase the variation of groundwater level and the maximum effect occurs close to the constant head boundary because of the linear mean hydraulic gradient. The correlation of groundwater level decreases with temporal interval and spatial distance. In addition, the heterogeneity enhances the correlation of groundwater level, especially at larger time intervals and small spatial distances.

  13. Geomorphic interaction among climate, sea levels and karst groundwater: the Taranto area (South of Italy)

    Science.gov (United States)

    Spilotro, Giuseppe; Fidelibus, Maria Dolores; Argentiero, Ilenia; Pellicani, Roberta; Parisi, Alessandro; Di Modugno, Antonella

    2017-04-01

    The area of Taranto (Apulia region, Italy) has an extraordinary environmental and landscape value, which derives from its specific geological, geomorphological and hydrogeological conditions: they represent the effect of a complex mechanism of interaction in the geological time among the sea, its level variations and stands driven by climate changes, karst groundwater and the geo lithological frame. The knowledge of this interaction spans over two very different time duration: the first is subsequent to the sedimentary pleistocenic deposition and diagenesis and lasts until the late Holocene; the second spans over a more limited time durations, from the LIA until today, and its knowledge is mainly based on hystorical topographic records and reports. The general geological and stratigraphical setting is represented by marine deposits, which fill the Bradanic Trough, shaped in the upper part as marine terraces bordering the W and SW side of the Murgian carbonate platform (Apulia, South of Italy) as well. This latter constitutes an important karst hydro-structure, fed by precipitation, bordered on the opposite side of the Bradanic Trough by the Adriatic Sea. Fresh groundwater hosted in the huge coastal aquifer freely flows towards the Adriatic coast, while on the opposite W-NW side, the continuous confinement by the impermeable filling of the trough, forces the underground drainage of the aquifer towards the Ionian Sea just in the Taranto area. The overall flow rate of the groundwater through submarine and subaerial coastal springs, according to the current sea level, is significant and currently estimated in about 18 m3/sec. Climate changes have forced over geological time, but also in shorter periods, sea level changes and stands, consequently correlated to groundwater levels. This allowed genesis of selected karst levels, of regional extension, both at the surface or underground, which arise as typical forms, namely polje and karst plane inland, terraces on the sea

  14. Water-Level Monitoring Plan for the Hanford Groundwater Monitoring Project

    Energy Technology Data Exchange (ETDEWEB)

    D.R. Newcomer; J.P. McDonald; M.A. Chamness

    1999-09-30

    This document presents the water-level monitoring plan for the Hanford Groundwater Monitoring Project, conducted by the Pacific Northwest National Laboratory (PNNL). Water-level monitoring of the groundwater system beneath the Hanford Site is performed to fulfill the requirements of various state and federal regulations, orders, and agreements. The primary objective of this monitoring is to determine groundwater flow rates and directions. To meet this and other objectives, water-levels are measured annually in monitoring wells completed within the unconfined aquifer system, the upper basalt-confined aquifer system, and in the lower basalt-confined aquifers for surveillance monitoring. At regulated waste units, water levels are taken monthly, quarterly, semi-annually, or annually, depending on the hydrogeologic conditions and regulatory status of a given site. The techniques used to collect water-level data are described in this document along with the factors that affect the quality of the data and the strategies employed by the project to minimize error in the measurement and interpretation of water levels. Well networks are presented for monitoring the unconfined aquifer system, the upper basalt-confined aquifer system, and the lower basalt-confined aquifers, all at a regional scale (surveillance monitoring), as well as the local-scale well networks for each of the regulated waste units studied by this project (regulated-unit monitoring). The criteria used to select wells for water-table monitoring are discussed. It is observed that poor well coverage for surveillance water-table monitoring exists south and west of the 200-West Area, south of the 100-F Area, and east of B Pond and the Treated Effluent Disposal Facility (TEDF). This poor coverage results from a lack of wells suitable for water-table monitoring, and causes uncertainty in representation of the regional water-table in these areas. These deficiencies are regional in scale and apply to regions outside

  15. Groundwater monitoring in the Savannah River Plant Low Level Waste Burial Ground

    Energy Technology Data Exchange (ETDEWEB)

    Carlton, W.H.

    1983-12-31

    This document describes chemical mechanisms that may affect trace-level radionuclide migration through acidic sandy clay soils in a humid environment, and summarizes the extensive chemical and radiochemical analyses of the groundwater directly below the SRP Low-Level Waste (LLW) Burial Ground (643-G). Anomalies were identified in the chemistry of individual wells which appear to be related to small amounts of fission product activity that have reached the water table. The chemical properties which were statistically related to trace level transport of Cs-137 and Sr-90 were iron, potassium, sodium and calcium. Concentrations on the order of 100 ppM appear sufficient to affect nuclide migration. Several complexation mechanisms for plutonium migration were investigated.

  16. Wavelet coupled MARS and M5 Model Tree approaches for groundwater level forecasting

    Science.gov (United States)

    Rezaie-balf, Mohammad; Naganna, Sujay Raghavendra; Ghaemi, Alireza; Deka, Paresh Chandra

    2017-10-01

    In this study, two different machine learning models, Multivariate Adaptive Regression Splines (MARS) and M5 Model Trees (MT) have been applied to simulate the groundwater level (GWL) fluctuations of three shallow open wells within diverse unconfined aquifers. The Wavelet coupled MARS and MT hybrid models were developed in an attempt to further increase the GWL forecast accuracy. The Discrete Wavelet Transform (DWT) which is particularly effective in dealing with non-stationary time-series data was employed to decompose the input time series into various sub-series components. Historical data of 10 years (August-1996 to July-2006) comprising monthly groundwater level, rainfall, and temperature were used to calibrate and validate the models. The models were calibrated and tested for one, three and six months ahead forecast horizons. The wavelet coupled MARS and MT models were compared with their simple counterpart using standard statistical performance evaluation measures such as Root Mean Square Error (RMSE), Normalized Nash-Sutcliffe Efficiency (NNSE) and Coefficient of Determination (R2) . The wavelet coupled MARS and MT models developed using multi-scale input data performed better compared to their simple counterpart and the forecast accuracy of W-MARS models were superior to that of W-MT models. Specifically, the DWT offered a better discrimination of non-linear and non-stationary trends that were present at various scales in the time series of the input variables thus crafting the W-MARS models to provide more accurate GWL forecasts.

  17. Wavelet-entropy data pre-processing approach for ANN-based groundwater level modeling

    Science.gov (United States)

    Nourani, Vahid; Alami, Mohammad Taghi; Vousoughi, Farnaz Daneshvar

    2015-05-01

    Accurate and reliable groundwater level forecasting models can help ensure the sustainable use of a watershed's aquifers for urban and rural water supply. In this paper, a Self-Organizing-Map (SOM)-based clustering technique was used to identify spatially homogeneous clusters of groundwater level (GWL) data for a feed-forward neural network (FFNN) to model one and multi-step-ahead GWLs. The wavelet transform (WT) was also used to extract dynamic and multi-scale features of the non-stationary GWL, runoff and rainfall time series. The performance of the FFNN model was compared to the newly proposed combined WT-FFNN model and also the conventional linear forecasting method of ARIMAX (Auto Regressive Integrated Moving Average with exogenous input). GWL predictions were investigated under three different scenarios. The results indicated that the proposed FFNN model coupled with the SOM-based clustering method decreased the dimensionality of the input variables and consequently the complexity of the FFNN models. On the other hand, the application of the wavelet transform to GWL data increased the performance of the FFNN model up to 15.3% in average by revealing the dominant periods of the process.

  18. Optimisation of groundwater level monitoring networks using geostatistical modelling based on the Spartan family variogram and a genetic algorithm method

    Science.gov (United States)

    Parasyris, Antonios E.; Spanoudaki, Katerina; Kampanis, Nikolaos A.

    2016-04-01

    Groundwater level monitoring networks provide essential information for water resources management, especially in areas with significant groundwater exploitation for agricultural and domestic use. Given the high maintenance costs of these networks, development of tools, which can be used by regulators for efficient network design is essential. In this work, a monitoring network optimisation tool is presented. The network optimisation tool couples geostatistical modelling based on the Spartan family variogram with a genetic algorithm method and is applied to Mires basin in Crete, Greece, an area of high socioeconomic and agricultural interest, which suffers from groundwater overexploitation leading to a dramatic decrease of groundwater levels. The purpose of the optimisation tool is to determine which wells to exclude from the monitoring network because they add little or no beneficial information to groundwater level mapping of the area. Unlike previous relevant investigations, the network optimisation tool presented here uses Ordinary Kriging with the recently-established non-differentiable Spartan variogram for groundwater level mapping, which, based on a previous geostatistical study in the area leads to optimal groundwater level mapping. Seventy boreholes operate in the area for groundwater abstraction and water level monitoring. The Spartan variogram gives overall the most accurate groundwater level estimates followed closely by the power-law model. The geostatistical model is coupled to an integer genetic algorithm method programmed in MATLAB 2015a. The algorithm is used to find the set of wells whose removal leads to the minimum error between the original water level mapping using all the available wells in the network and the groundwater level mapping using the reduced well network (error is defined as the 2-norm of the difference between the original mapping matrix with 70 wells and the mapping matrix of the reduced well network). The solution to the

  19. Purification and Detection of 39Ar in Groundwater Samples via Low-Level Counting

    Science.gov (United States)

    Mace, E. K.; Aalseth, C.; Brandenberger, J. M.; Humble, P.; Panisko, M.; Seifert, A.; Williams, R. M.

    2015-12-01

    Argon-39 can be used as a radiotracer to age-date groundwater aquifers to study recharge rates and to better understand the mean residence time, or age distributions, of groundwater. Argon-39 (with a half-life of 269 years) is created in the atmosphere by cosmic rays interacting with argon in the air (primarily 40Ar). The use of 39Ar as a radiotracer fills a gap in the age dating range which is currently covered by 3H/3He or 85Kr (1000 years); 39Ar fills the intermediate time scale range from 50-1000 years where the previously established radiotracers are not adequate. We will introduce the process for purifying and detecting 39Ar in ground water using ultra-low-background proportional counters (ULBPCs) at the shallow underground laboratory at Pacific Northwest National Laboratory. Argon-39 is detected through direct beta counting using ULBPCs loaded with a mixture of geologic argon (extracted from a carbon dioxide well with no measureable 39Ar activity) and methane, which enhances the sensitivity for 39Ar measurements. The ULBPCs have been shown to have a background count rate of 148 counts per day (cpd) in the energy range 3-400 keV when filled with 10 atm of P-10 counting gas (90% geologic Ar, 10% CH4). Initial demonstration samples were collected from groundwater aquifers in Fresno, California supported by the United States Geological Survey (USGS). A discussion of the sampling technique to degas the water from these wells and to then purify it for counting will be presented. In order to quantify the 39Ar contribution in the groundwater samples, the ULBPCs were characterized to determine two components: 1) the detector efficiency to modern levels of 39Ar, and 2) the remaining detector background (using geologic sourced argon which is free from 39Ar - no measureable 39Ar activity). These characterization results will be presented along with a discussion of the quantification of the 39Ar age of the demonstration measurements.

  20. Can We Remove Secular Terms for Analytical Solution of Groundwater Response under Tidal Influence?

    CERN Document Server

    Munusamy, Selva Balaji

    2016-01-01

    This paper presents a secular term removal methodology based on the homotopy perturbation method for analytical solutions of nonlinear problems with periodic boundary condition. The analytical solution for groundwater response to tidal fluctuation in a coastal unconfined aquifer system with the vertical beach is provided as an example. The non-linear one-dimensional Boussinesq's equation is considered as the governing equation for the groundwater flow. An analytical solution is provided for non-dimensional Boussinesq's equation with cosine harmonic boundary condition representing tidal boundary condition. The analytical solution is obtained by using homotopy perturbation method with a virtual embedding parameter. The present approach does not require pre-specified perturbation parameter and also facilitates secular terms elimination in the perturbation solution. The solutions starting from zeroth-order up to third-order are obtained. The non-dimensional expression, $A/D_{\\infty}$ emerges as an implicit parame...

  1. Ground-water protection, low-level waste, and below regulatory concern: What`s the connection?

    Energy Technology Data Exchange (ETDEWEB)

    Gruhlke, J.M.; Galpin, F.L. [Environmental Protection Agency, Washington, DC (United States). Office of Radiation Programs

    1991-12-31

    The Environmental Protection Agency (EPA) has a responsibility to protect ground water and drinking water under a wide variety of statutes. Each statute establishes different but specific requirements for EPA and applies to diverse environmental contaminants. Radionuclides are but one of the many contaminants subject to this regulatory matrix. Low-level radioactive waste (LLW) and below regulatory concern (BRC) are but two of many activities falling into this regulatory structure. The nation`s ground water serves as a major source of drinking water, supports sensitive ecosystems, and supplies the needs of agriculture and industry. Ground water can prove enormously expensive to clean up. EPA policy for protecting ground water has evolved considerably over the last ten years. The overall goal is to prevent adverse effects to human health, both now and in the future, and to protect the integrity of the nation`s ground-water resources. The Agency uses the Maximum Contaminant Levels (MCLs) under the Safe Drinking Water Act as reference points for protection in both prevention and remediation activities. What`s the connection? Both low-level waste management and disposal activities and the implementation of below regulatory concern related to low-level waste disposal have the potential for contaminating ground water. EPA is proposing to use the MCLs as reference points for low-level waste disposal and BRC disposal in order to define limits to the environmental contamination of ground water that is, or may be, used for drinking water.

  2. Application of a Coupled Vegetation Competition and Groundwater Simulation Model to Study Effects of Sea Level Rise and Storm Surges on Coastal Vegetation

    Directory of Open Access Journals (Sweden)

    Su Yean Teh

    2015-09-01

    Full Text Available Global climate change poses challenges to areas such as low-lying coastal zones, where sea level rise (SLR and storm-surge overwash events can have long-term effects on vegetation and on soil and groundwater salinities, posing risks of habitat loss critical to native species. An early warning system is urgently needed to predict and prepare for the consequences of these climate-related impacts on both the short-term dynamics of salinity in the soil and groundwater and the long-term effects on vegetation. For this purpose, the U.S. Geological Survey’s spatially explicit model of vegetation community dynamics along coastal salinity gradients (MANHAM is integrated into the USGS groundwater model (SUTRA to create a coupled hydrology–salinity–vegetation model, MANTRA. In MANTRA, the uptake of water by plants is modeled as a fluid mass sink term. Groundwater salinity, water saturation and vegetation biomass determine the water available for plant transpiration. Formulations and assumptions used in the coupled model are presented. MANTRA is calibrated with salinity data and vegetation pattern for a coastal area of Florida Everglades vulnerable to storm surges. A possible regime shift at that site is investigated by simulating the vegetation responses to climate variability and disturbances, including SLR and storm surges based on empirical information.

  3. Application of a coupled vegetation competition and groundwater simulation model to study effects of sea level rise and storm surges on coastal vegetation

    Science.gov (United States)

    Teh, Su Yean; Turtora, Michael; DeAngelis, Don; Jiang Jiang,; Pearlstine, Leonard G.; Smith, Thomas; Koh, Hock Lye

    2015-01-01

    Global climate change poses challenges to areas such as low-lying coastal zones, where sea level rise (SLR) and storm-surge overwash events can have long-term effects on vegetation and on soil and groundwater salinities, posing risks of habitat loss critical to native species. An early warning system is urgently needed to predict and prepare for the consequences of these climate-related impacts on both the short-term dynamics of salinity in the soil and groundwater and the long-term effects on vegetation. For this purpose, the U.S. Geological Survey’s spatially explicit model of vegetation community dynamics along coastal salinity gradients (MANHAM) is integrated into the USGS groundwater model (SUTRA) to create a coupled hydrology–salinity–vegetation model, MANTRA. In MANTRA, the uptake of water by plants is modeled as a fluid mass sink term. Groundwater salinity, water saturation and vegetation biomass determine the water available for plant transpiration. Formulations and assumptions used in the coupled model are presented. MANTRA is calibrated with salinity data and vegetation pattern for a coastal area of Florida Everglades vulnerable to storm surges. A possible regime shift at that site is investigated by simulating the vegetation responses to climate variability and disturbances, including SLR and storm surges based on empirical information.

  4. Climate change impact on groundwater levels: ensemble modelling of extreme values

    Directory of Open Access Journals (Sweden)

    J. Kidmose

    2012-06-01

    Full Text Available This paper presents a first attempt to estimate future groundwater levels by applying extreme value statistics on predictions from a hydrological model. Climate for the future period, 2081–2100, are represented by projections from nine combinations of three global climate models and six regional climate models, and downscaled with two different methods. An integrated surface water/groundwater model is forced with precipitation, temperature, and evapotranspiration from the 18 model – and downscaling combinations. Extreme value analyses are performed on the hydraulic head changes from a control period (1991–2010 to the future period for the 18 combinations. Hydraulic heads for return periods of 21, 50 and 100 yr (T21–100 are estimated. Three uncertainty sources are evaluated; climate models, downscaling and extreme value statistics. Of these sources, downscaling dominates for the higher return periods of 50 and 100 yr, whereas uncertainty from climate models and downscaling are similar for lower return periods. Uncertainty from the extreme value statistics only contribute up to around 10% of the uncertainty from the three sources.

  5. DETERMINATION OF THE GROUND-WATER LEVEL BY MODERN NON-DISTRUCTIVE METHODS (GPR TECHNOLOGY

    Directory of Open Access Journals (Sweden)

    I. C. NICU

    2011-03-01

    Full Text Available Determination of the ground-water level by modern non-dis¬tructive methods (ground-penetrating radar technology. Ground Penetrating Radar (GPR is now a well-accepted geophysical technique, which unfortunately in our country its less used. Historically, the development of GPR comes from the use of radio echosounding to determine ice thickness and it was only a short step to enlarge the domain of research such as permafrost, geological investigation (bedrock, sedimentology, environmental assessment and hydrogeophysical studies (under-ground water location, soil water content. The GPR method measures the travel time of electromagnetic impulses in subsurface materials. An impulse radar system radiates repetitive electromagnetic impulses into the soil. A bandwidth antenna is usually placed in close proximity and electromagnetic coupled to the ground surface. It detects and measures the depth of reflecting discontinuities in subsurface soils and other earth materials to within a few centimeters depending of antenna frequency. For over 30 years, GPR has been used extensively for hydropedological investigations. Our research aims to determine the groundwater to estimate the degree of evolution of hydro-geomorphological processes.

  6. Space-Time Modelling of Groundwater Level Using Spartan Covariance Function

    Science.gov (United States)

    Varouchakis, Emmanouil; Hristopulos, Dionissios

    2014-05-01

    Geostatistical models often need to handle variables that change in space and in time, such as the groundwater level of aquifers. A major advantage of space-time observations is that a higher number of data supports parameter estimation and prediction. In a statistical context, space-time data can be considered as realizations of random fields that are spatially extended and evolve in time. The combination of spatial and temporal measurements in sparsely monitored watersheds can provide very useful information by incorporating spatiotemporal correlations. Spatiotemporal interpolation is usually performed by applying the standard Kriging algorithms extended in a space-time framework. Spatiotemoral covariance functions for groundwater level modelling, however, have not been widely developed. We present a new non-separable theoretical spatiotemporal variogram function which is based on the Spartan covariance family and evaluate its performance in spatiotemporal Kriging (STRK) interpolation. The original spatial expression (Hristopulos and Elogne 2007) that has been successfully used for the spatial interpolation of groundwater level (Varouchakis and Hristopulos 2013) is modified by defining the following space-time normalized distance h = °h2r-+-α h2τ, hr=r- ξr, hτ=τ- ξτ; where r is the spatial lag vector, τ the temporal lag vector, ξr is the correlation length in position space (r) and ξτ in time (τ), h the normalized space-time lag vector, h = |h| is its Euclidean norm of the normalized space-time lag and α the coefficient that determines the relative weight of the time lag. The space-time experimental semivariogram is determined from the biannual (wet and dry period) time series of groundwater level residuals (obtained from the original series after trend removal) between the years 1981 and 2003 at ten sampling stations located in the Mires hydrological basin in the island of Crete (Greece). After the hydrological year 2002-2003 there is a significant

  7. Groundwater Governance in the United States: Common Priorities and Challenges.

    Science.gov (United States)

    Megdal, Sharon B; Gerlak, Andrea K; Varady, Robert G; Huang, Ling-Yee

    2015-01-01

    Groundwater is a critical component of the water supply for agriculture, urban areas, industry, and ecosystems, but managing it is a challenge because groundwater is difficult to map, quantify, and evaluate. Until recently, study and assessment of governance of this water resource has been largely neglected. A survey was developed to query state agency officials about the extent and scope of groundwater use, groundwater laws and regulations, and groundwater tools and strategies. Survey responses revealed key findings: states' legal frameworks for groundwater differ widely in recognizing the hydrologic connection between surface water and groundwater, the needs of groundwater-dependent ecosystems, and the protection of groundwater quality; states reported a range in capacity to enforce groundwater responsibilities; and states have also experienced substantial changes in groundwater governance in the past few decades. Overall, groundwater governance across the United States is fragmented. States nevertheless identified three common priorities for groundwater governance: water quality and contamination, conflicts between users, and declining groundwater levels. This survey represents an initial step in a broader, continuing effort to characterize groundwater governance practices in the United States.

  8. Combining natural background levels (NBLs) assessment with indicator kriging analysis to improve groundwater quality data interpretation and management.

    Science.gov (United States)

    Ducci, Daniela; de Melo, M Teresa Condesso; Preziosi, Elisabetta; Sellerino, Mariangela; Parrone, Daniele; Ribeiro, Luis

    2016-11-01

    The natural background level (NBL) concept is revisited and combined with indicator kriging method to analyze the spatial distribution of groundwater quality within a groundwater body (GWB). The aim is to provide a methodology to easily identify areas with the same probability of exceeding a given threshold (which may be a groundwater quality criteria, standards, or recommended limits for selected properties and constituents). Three case studies with different hydrogeological settings and located in two countries (Portugal and Italy) are used to derive NBL using the preselection method and validate the proposed methodology illustrating its main advantages over conventional statistical water quality analysis. Indicator kriging analysis was used to create probability maps of the three potential groundwater contaminants. The results clearly indicate the areas within a groundwater body that are potentially contaminated because the concentrations exceed the drinking water standards or even the local NBL, and cannot be justified by geogenic origin. The combined methodology developed facilitates the management of groundwater quality because it allows for the spatial interpretation of NBL values.

  9. Geophysical data integration, stochastic simulation and significance analysis of groundwater responses using ANOVA in the Chicot Aquifer system, Louisiana, USA

    Science.gov (United States)

    Rahman, A.; Tsai, F.T.-C.; White, C.D.; Carlson, D.A.; Willson, C.S.

    2008-01-01

    Data integration is challenging where there are different levels of support between primary and secondary data that need to be correlated in various ways. A geostatistical method is described, which integrates the hydraulic conductivity (K) measurements and electrical resistivity data to better estimate the K distribution in the Upper Chicot Aquifer of southwestern Louisiana, USA. The K measurements were obtained from pumping tests and represent the primary (hard) data. Borehole electrical resistivity data from electrical logs were regarded as the secondary (soft) data, and were used to infer K values through Archie's law and the Kozeny-Carman equation. A pseudo cross-semivariogram was developed to cope with the resistivity data non-collocation. Uncertainties in the auto-semivariograms and pseudo cross-semivariogram were quantified. The groundwater flow model responses by the regionalized and coregionalized models of K were compared using analysis of variance (ANOVA). The results indicate that non-collocated secondary data may improve estimates of K and affect groundwater flow responses of practical interest, including specific capacity and drawdown. ?? Springer-Verlag 2007.

  10. Method for the Preparation of Hazard Map in Urban Area Using Soil Depth and Groundwater Level

    Science.gov (United States)

    Kim, Sung-Wook; Choi, Eun-Kyeong; Cho, Jin Woo; Lee, Ju-Hyoung

    2017-04-01

    The hazard maps for predicting collapse on natural slopes consists of a combination of topographic, hydrological, and geological factors. Topographic factors are extracted from DEM, including aspect, slope, curvature, and topographic index. Hydrological factors, such as distance to drainage, drainage density, stream-power index, and wetness index are most important factors for slope instability. However, most of the urban areas are located on the plains and it is difficult to apply the hazard map using the topography and hydrological factors. In order to evaluate the risk of collapse of flat and low slope areas, soil depth and groundwater level data were collected and used as a factor for interpretation. In addition, the reliability of the hazard map was compared with the disaster history of the study area (Gangnam-gu and Yeouido district). In the disaster map of the disaster prevention agency, the urban area was mostly classified as the stable area and did not reflect the collapse history. Soil depth, drainage conditions and groundwater level obtained from boreholes were added as input data of hazard map, and disaster vulnerability increased at the location where the actual collapse points. In the study area where damage occurred, the moderate and low grades of the vulnerability of previous hazard map were 12% and 88%, respectively. While, the improved map showed 2% high grade, moderate grade 29%, low grade 66% and very low grade 2%. These results were similar to actual damage. Keywords: hazard map, urban area, soil depth, ground water level Acknowledgement This research was supported by a Grant from a Strategic Research Project (Horizontal Drilling and Stabilization Technologies for Urban Search and Rescue (US&R) Operation) funded by the Korea Institute of Civil Engineering and Building Technology.

  11. Characterization of sediment and measurement of groundwater levels and temperatures, Camas National Wildlife Refuge, eastern Idaho

    Science.gov (United States)

    Twining, Brian V.; Rattray, Gordon W.

    2016-11-02

    The Camas National Wildlife Refuge (Refuge) in eastern Idaho, established in 1937, contains wetlands, ponds, and wet meadows that are essential resting and feeding habitat for migratory birds and nesting habitat for waterfowl. Initially, natural sources of water supported these habitats. However, during the past few decades, climate change and changes in surrounding land use have altered and reduced natural groundwater and surface water inflows such that the wetlands, ponds, and wet meadows are now maintained through water management and groundwater pumping. These water management activities have proven to be inefficient and costly, prompting the Refuge to develop alternative water management options that are more efficient and less expensive. The U.S. Geological Survey, in cooperation with the U.S. Fish and Wildlife Service, is studying the hydrogeology at the Refuge to provide information for developing alternative water management options.The hydrogeologic studies at the Refuge included characterizing the type, distribution, and hydraulic conductivity of surficial sediments and measuring water levels and temperatures in monitoring wells. Four monitoring wells and seven soil probe coreholes were drilled at the Refuge. Seven water level and temperature data loggers were installed in the wells and water levels and temperatures were continuously recorded from November 2014 to June 2016. Sediment cores were collected from the coreholes and sediment type and distribution were characterized from drillers’ notes, geophysical logs, corehole samples, and particle grain-size analysis. The hydraulic conductivities of sediments were estimated using the measured average grain size and the assumed textural maturity of the sediment, and ranged from about 20 to 290 feet per day.

  12. Records of wells, ground-water levels, and ground-water withdrawals in the lower Goose Creek Basin, Cassia County, Idaho

    Science.gov (United States)

    Mower, R.W.

    1954-01-01

    Investigations by the United States Geological Survey of Ground Water in the Southern border area of the Snake Rive Plain, south of the Snake River, a re concerned at the present time with delineation of the principal ground-water districts, the extent and location of existing ground-water developments, the possibilities for additional development, and the effects of ground-water development on the regimen of streams and reservoirs whose waters are appropriate for beneficial use. The lower part of the Goose Creek Basin is one of the important ground-water districts of the southern plains area and there are substantial but spotty developments of ground water for irrigation in the basin. Several thousand irrigable acres that are now dry could be put under irrigation if a dependable supply of ground water could be developed. The relations of the ground-water reservoirs to the regime of the Snake River and Goose Cree, and to the large body of ground water in the Snake River Plain north of the Snake, are poorly known. A large amount of geologic and hydrologic study remains to be done before those relations can be accurately determined. Investigations will be continued in the future but file work and preparation of a comprehensive report inevitably will be delayed. Therefore the available records are presented herein in order to make them accessible to farmers, well drillers, government agencies, and the general public. Interpretation of the records is not attempted in this report and is deferred pending the accumulation of additional and quantitative information. The data summarized herein include records of the locations and physical characteristics of wells, the depth to water in wells, fluctuations of water levels in observation wells, and estimated rates and volumes of seasonal ans yearly ground-water pumpage for irrigation, municipal, and other uses. This information is complete for work done as of December 31, 1952. The investigations upon which this report is

  13. Vertical groundwater storage properties and changes in confinement determined using hydraulic head response to atmospheric tides

    Science.gov (United States)

    Acworth, R. Ian; Rau, Gabriel C.; Halloran, Landon J. S.; Timms, Wendy A.

    2017-04-01

    Accurate determination of groundwater state of confinement and compressible storage properties at vertical resolution over depth is notoriously difficult. We use the hydraulic head response to atmospheric tides at 2 cpd frequency as a tracer to quantify barometric efficiency (BE) and specific storage (Ss) over depth. Records of synthesized Earth tides, atmospheric pressure, and hydraulic heads measured in nine piezometers completed at depths between 5 and 55 m into unconsolidated smectitic clay and silt, sand and gravel were examined in the frequency domain. The barometric efficiency increased over depth from ˜0.05 in silty clay to ˜0.15 in sands and gravels. BE for silty clay was confirmed by calculating the loading efficiency as 0.95 using rainfall at the surface. Specific storage was calculated using effective rather than total moisture. The differences in phase between atmospheric pressure and hydraulic heads at 2 cpd were ˜180° below 10 m indicating confined conditions despite the low BE. Heads in the sediment above a fine sand and silt layer at 12 m exhibited a time variable phase difference between 0° and 180° indicating varying confinement. Our results illustrate that the atmospheric tide at 2 cpd is a powerful natural tracer for quantifying groundwater state of confinement and compressible storage properties in layered formations from hydraulic heads and atmospheric pressure records without the need for externally induced hydraulic stress. This approach could significantly improve the development of conceptual hydrogeological model used for groundwater resource development and management.

  14. Pore Pressure Response to Groundwater Fluctuations in Saturated Double-Layered Soil

    Directory of Open Access Journals (Sweden)

    Hongwei Ying

    2015-01-01

    Full Text Available Analytical solutions are developed for one-dimensional consolidation of double-layered saturated soil subjected to groundwater fluctuations. The solutions are derived by an explicit mathematical procedure using Duhamel’s theorem in conjunction with a Fourier series, when groundwater fluctuation is described by a general time-dependent function and assumed to be the pore water pressure variations at the upper boundary. Taking as an example the harmonic groundwater fluctuation, the relevant response of the excess pore water pressure is discussed in detail, and the main influencing factors of the excess pore pressure distribution are analyzed. A dimensionless parameter θ has been introduced because it significantly affects the phase and the amplitude of excess pore pressures. The influences of the coefficients of permeability and compressibility of soil on the excess pore pressure distribution are different and cannot be incorporated into the coefficient of consolidation in double-layered soil. The relative permeability ratio of two clayey soils also plays an important role on the curves of the distributions of the excess pore pressures. The effects of the thickness of the soil layer on the excess pore pressure distribution should be considered together with the dimensionless parameter θ and the permeability and compressibility of the double-layered soil system.

  15. Impact of coal gangue on the level of main trace elements in the shallow groundwater of a mine reclamation area

    Institute of Scientific and Technical Information of China (English)

    Li Wei; Chen Longqian; Zhou Tianjian; Tang Qibao; Zhang Ting

    2011-01-01

    Coal gangue is the most used filling material during reclamation of areas suffering subsidence from mining.Main trace element levels (F,As,Hg,and Pb) in shallow groundwater in the reclamation area may be affected by leaching from the gangue.This can has an impact on the application of the water for agricultural irrigation or use as drinking water.Therefore,it is of great significance to understand the effect coal gangue has on the shallow groundwater of a reclaimed area.We studied the effect of coal gangue on fluorine,arsenic,mercury,and lead levels in the shallow groundwater of a reclamation area by testing the water and the coal gangue.One well near the reclamation area was used as a control well and element levels in water from this well and from the soil next to the well were also measured.The results show that the levels of these elements are increasing in the reclamation area over time.The increase in fluorine,arsenic,mercury,and lead in monitor wells varies from 7.42% to 8.26%,from 7.13% to 7.90%,from 4.85% to 6.48%,and from 4.69% to 6.42%,respectively.Fluorine and arsenic levels are lower in monitor wells than in the control water.The other elements are found in greater concentration than in the control.The Nemerow index also indicates that the shallow groundwater in the reclamation area Ⅰ is moderately affected by the back-filling coal gangue,while the shallow groundwater in the reclamation area Ⅱ and Ⅲ are slightly affected by the back-filling coal gangue.This shallow groundwater could be used for agricultural irrigation or for drinking.

  16. Groundwater-level and storage-volume changes in the Equus Beds aquifer near Wichita, Kansas, predevelopment through January 2015

    Science.gov (United States)

    Whisnant, Joshua A.; Hansen, Cristi V.; Eslick, Patrick J.

    2015-10-01

    Development of the Wichita well field began in the 1940s in the Equus Beds aquifer to provide the city of Wichita, Kansas, a new water-supply source. After development of the Wichita well field began, groundwater levels began to decline. Extensive development of irrigation wells that began in the 1970s also contributed to substantial groundwater-level declines. Groundwater-level declines likely enhance movement of brine from past oil and gas production near Burrton, Kansas, and natural saline water from the Arkansas River into the Wichita well field. Groundwater levels reached a historical minimum in 1993 because of drought conditions, irrigation, and the city of Wichita’s withdrawals from the aquifer. In 1993, the city of Wichita adopted the Integrated Local Water Supply Program to ensure that Wichita’s water needs would be met through the year 2050 and beyond as part of its efforts to manage the part of the Equus Beds aquifer Wichita uses. A key component of the Integrated Local Water Supply Program was the Equus Beds Aquifer Storage and Recovery project. The Aquifer Storage and Recovery project’s goal is to store and eventually recover groundwater and help protect the Equus Beds aquifer from oil-field brine water near Burrton, Kansas, and saline water from the Arkansas River. Since 1940, the U.S. Geological Survey has monitored groundwater levels and storage-volume changes in the Equus Beds aquifer to provide data to the city of Wichita in order to better manage its water supply.

  17. Quantifying uncertainty in predictions of groundwater levels using formal likelihood methods

    Science.gov (United States)

    Marchant, Ben; Mackay, Jonathan; Bloomfield, John

    2016-09-01

    Informal and formal likelihood methods can be used to quantify uncertainty in modelled predictions of groundwater levels (GWLs). Informal methods use a relatively subjective criterion to identify sets of plausible or behavioural parameters of the GWL models. In contrast, formal methods specify a statistical model for the residuals or errors of the GWL model. The formal uncertainty estimates are only reliable when the assumptions of the statistical model are appropriate. We apply the formal approach to historical reconstructions of GWL hydrographs from four UK boreholes. We test whether a model which assumes Gaussian and independent errors is sufficient to represent the residuals or whether a model which includes temporal autocorrelation and a general non-Gaussian distribution is required. Groundwater level hydrographs are often observed at irregular time intervals so we use geostatistical methods to quantify the temporal autocorrelation rather than more standard time series methods such as autoregressive models. According to the Akaike Information Criterion, the more general statistical model better represents the residuals of the GWL model. However, no substantial difference between the accuracy of the GWL predictions and the estimates of their uncertainty is observed when the two statistical models are compared. When the general model is applied, significant temporal correlation over periods ranging from 3 to 20 months is evident for the different boreholes. When the GWL model parameters are sampled using a Markov Chain Monte Carlo approach the distributions based on the general statistical model differ from those of the Gaussian model, particularly for the boreholes with the most autocorrelation. These results suggest that the independent Gaussian model of residuals is sufficient to estimate the uncertainty of a GWL prediction on a single date. However, if realistically autocorrelated simulations of GWL hydrographs for multiple dates are required or if the

  18. Predictive models applied to groundwater level forecasting: a preliminary experience on the alluvial aquifer of the Magra River (Italy).

    Science.gov (United States)

    Brozzo, Gianpiero; Doveri, Marco; Lelli, Matteo; Scozzari, Andrea

    2010-05-01

    the natural system can be partly explained in terms of its impulse response, identified as an arbitrary function, optimally fitted to the behavior observed in the past time series. In the proposed method, the approximation of the natural behavior of the system derives from the decomposition of the excitation signals (input parameters) into sequences of discrete values. Data fed to the ANN are thus pre-processed according to this concept. In the particular case study presented in this work, the proximity of the Magra River mixes the short-term effects of the hydraulic level of the river with the slower rainfall effects that diffusely feed the groundwater system, making the analysis even more challenging. In addition to piezometric levels, also continuous conductivity data series are available for the same period, and have been taken into account separately in this preliminary experience. The availability of the electrical conductivity parameter opens the way to the modeling of the different contributions to the groundwater reservoir, and may also enable the prediction of some water quality features, as discussed in this work. The preliminary analysis of meteorological and hydrologic data sets is discussed in this work, and goes through the following steps: a) description of the dataset, b) description of the model developed, c) model tuning, d) discussion of results and applicability as a predictor.

  19. Groundwater-level change and evaluation of simulated water levels for irrigated areas in Lahontan Valley, Churchill County, west-central Nevada, 1992 to 2012

    Science.gov (United States)

    Smith, David W.; Buto, Susan G.; Welborn, Toby L.

    2016-09-14

    The acquisition and transfer of water rights to wetland areas of Lahontan Valley, Nevada, has caused concern over the potential effects on shallow aquifer water levels. In 1992, water levels in Lahontan Valley were measured to construct a water-table map of the shallow aquifer prior to the effects of water-right transfers mandated by the Fallon Paiute-Shoshone Tribal Settlement Act of 1990 (Public Law 101-618, 104 Stat. 3289). From 1992 to 2012, approximately 11,810 water-righted acres, or 34,356 acre-feet of water, were acquired and transferred to wetland areas of Lahontan Valley. This report documents changes in water levels measured during the period of water-right transfers and presents an evaluation of five groundwater-flow model scenarios that simulated water-level changes in Lahontan Valley in response to water-right transfers and a reduction in irrigation season length by 50 percent.Water levels measured in 98 wells from 2012 to 2013 were used to construct a water-table map. Water levels in 73 of the 98 wells were compared with water levels measured in 1992 and used to construct a water-level change map. Water-level changes in the 73 wells ranged from -16.2 to 4.1 feet over the 20-year period. Rises in water levels in Lahontan Valley may correspond to annual changes in available irrigation water, increased canal flows after the exceptionally dry and shortened irrigation season of 1992, and the increased conveyance of water rights transferred to Stillwater National Wildlife Refuge. Water-level declines generally occurred near the boundary of irrigated areas and may be associated with groundwater pumping, water-right transfers, and inactive surface-water storage reservoirs. The largest water-level declines were in the area near Carson Lake.Groundwater-level response to water-right transfers was evaluated by comparing simulated and observed water-level changes for periods representing water-right transfers and a shortened irrigation season in areas near Fallon

  20. How geomorphology and groundwater level affect the spatio-temporal variability of riverine cold water patches?

    Science.gov (United States)

    Wawrzyniak, Vincent; Piégay, Hervé; Allemand, Pascal; Vaudor, Lise; Goma, Régis; Grandjean, Philippe

    2016-04-01

    Temperature is a key factor for river ecosystems. In summer, patches of cold water are formed in the river by groundwater seepage. These patches have strong ecological significance and extend to the surface water in a well-mixed riverine system. These patches can serve as thermal refuges for some fish species during summer. In this study, the temporal variability and spatial distribution of cold water patches were explored along a 50 km river reach (the lower Ain River, France) using thermal infrared airborne remote sensing. This study examines a new range of processes acting on cold water patches at different scales that have not previously been touched upon in the literature. Three airborne campaigns were conducted during the summers of 2010, 2011 and 2014. Based on these images, a large number of cold water patches were identified using an automated method. Four types of patches were observed: tributary plumes, cold side channels (former channels or point-bar backwater channels), side seeps (located directly in the river channel) and gravel bar seeps (occurring at the downstream end of gravel bars). Logistic regression was used to analyse the longitudinal distribution of cold water patches according to geomorphologic indicators reflecting current or past fluvial process. Side seeps were found to be related to the local geology. Cold side channels were correlated to contemporary and past lateral river mobility. Gravel bar seeps were related to the current development of bars and are more prevalent in wandering reaches than in single-bed incised and paved reaches. The logistic model was subsequently used to evaluate gravel bar seep variability in the past. The model suggests larger numbers of seeps in the mid-20th century when bar surface area was higher. Interannual variability in the occurrence and spatial extent of side seeps and gravel bar seeps appear to be related to groundwater level fluctuations. Cold side channels exhibited greater interannual stability

  1. Analysis of Water Level Fluctuations and TDS Variations in the Groundwater at Mewat (Nuh District, Haryana (India

    Directory of Open Access Journals (Sweden)

    Priyanka1

    2016-08-01

    Full Text Available Groundwater is the major source for fulfilling the water needs of domestic and agricultural sectors in Mewat district, Haryana, India and its continuous use has put an enormous pressure on the groundwater resource, which along with low rainfall and variable geographical conditions lead to the declining water levels. The other problem of this area is high salinity which is reported intruding to the freshwater zone1. Taking into account the twin problem of declining water level and high salinity the study was taken up jointly by National Institute of Hydrology, Roorkee; Sehgal Foundation, Gurgaon and Indian Institute of Technology, Roorkee. Groundwater level and TDS (Total dissolved solids data for pre-monsoon and post-monsoon seasons for the time period of 2011–2015 of 40 monitoring wells developed by Sehgal Foundation, Gurgaon was collected and analysed. It has been found that the groundwater level is decreasing in the area while TDS values show inconsistent trends during 2011-15. Further monitoring of the wells is continued to get the more information on water level and TDS which will help in facilitating the researchers in finding out the applicable solutions for the above problems in the Mewat, Haryana.

  2. Arsenic Removal from Natural Groundwater by Electrocoagulation Using Response Surface Methodology

    Directory of Open Access Journals (Sweden)

    A. M. García-Lara

    2014-01-01

    Full Text Available Contamination of natural groundwater by arsenic (As is a serious problem that appears in some areas of Northern Central Mexico (NCM. In this research, As was removed from NCM wells groundwater by the electrocoagulation (EC technique. Laboratory-scale arsenic electroremoval experiments were carried out at continuous flow rates between 0.25 and 1.00 L min−1 using current densities of 5, 10, and 20 A m−2. Experiments were performed under galvanostatic conditions during 5 min, at constant temperature and pH. The response surface methodology (RSM was used for the optimization of the processing variables (flow rate and current density, response modeling, and predictions. The highest arsenic removal efficiency from underground water (99% was achieved at low flow rates (0.25 L min−1 and high current densities (20 A m−2. The response models developed explained 93.7% variability for As removal efficiency.

  3. Spatiotemporal groundwater level modeling using hybrid artificial intelligence-meshless method

    Science.gov (United States)

    Nourani, Vahid; Mousavi, Shahram

    2016-05-01

    Uncertainties of the field parameters, noise of the observed data and unknown boundary conditions are the main factors involved in the groundwater level (GL) time series which limit the modeling and simulation of GL. This paper presents a hybrid artificial intelligence-meshless model for spatiotemporal GL modeling. In this way firstly time series of GL observed in different piezometers were de-noised using threshold-based wavelet method and the impact of de-noised and noisy data was compared in temporal GL modeling by artificial neural network (ANN) and adaptive neuro-fuzzy inference system (ANFIS). In the second step, both ANN and ANFIS models were calibrated and verified using GL data of each piezometer, rainfall and runoff considering various input scenarios to predict the GL at one month ahead. In the final step, the simulated GLs in the second step of modeling were considered as interior conditions for the multiquadric radial basis function (RBF) based solve of governing partial differential equation of groundwater flow to estimate GL at any desired point within the plain where there is not any observation. In order to evaluate and compare the GL pattern at different time scales, the cross-wavelet coherence was also applied to GL time series of piezometers. The results showed that the threshold-based wavelet de-noising approach can enhance the performance of the modeling up to 13.4%. Also it was found that the accuracy of ANFIS-RBF model is more reliable than ANN-RBF model in both calibration and validation steps.

  4. Optimal level of groundwater charge to promote rainwater usage for irrigation in rural Beijing

    NARCIS (Netherlands)

    X. Liang (Xiao); M.P. van Dijk (Meine Pieter)

    2011-01-01

    textabstractAbstract: Since groundwater is diminishing rapidly in rural Beijing, rainwater harvesting for irrigation is being promoted. As the cost of pumping up groundwater is low, farmers have few incentives to use rainwater. To promote the consumption of rainwater, the Beijing Water Authority may

  5. The backend design of an environmental monitoring system upon real-time prediction of groundwater level fluctuation under the hillslope.

    Science.gov (United States)

    Lin, Hsueh-Chun; Hong, Yao-Ming; Kan, Yao-Chiang

    2012-01-01

    The groundwater level represents a critical factor to evaluate hillside landslides. A monitoring system upon the real-time prediction platform with online analytical functions is important to forecast the groundwater level due to instantaneously monitored data when the heavy precipitation raises the groundwater level under the hillslope and causes instability. This study is to design the backend of an environmental monitoring system with efficient algorithms for machine learning and knowledge bank for the groundwater level fluctuation prediction. A Web-based platform upon the model-view controller-based architecture is established with technology of Web services and engineering data warehouse to support online analytical process and feedback risk assessment parameters for real-time prediction. The proposed system incorporates models of hydrological computation, machine learning, Web services, and online prediction to satisfy varieties of risk assessment requirements and approaches of hazard prevention. The rainfall data monitored from the potential landslide area at Lu-Shan, Nantou and Li-Shan, Taichung, in Taiwan, are applied to examine the system design.

  6. A Study of the Groundwater Level Spatial Variability in the Messara Valley of Crete

    Science.gov (United States)

    Varouchakis, E. A.; Hristopulos, D. T.; Karatzas, G. P.

    2009-04-01

    The island of Crete (Greece) has a dry sub-humid climate and marginal groundwater resources, which are extensively used for agricultural activities and human consumption. The Messara valley is located in the south of the Heraklion prefecture, it covers an area of 398 km2, and it is the largest and most productive valley of the island. Over-exploitation during the past thirty (30) years has led to a dramatic decrease of thirty five (35) meters in the groundwater level. Possible future climatic changes in the Mediterranean region, potential desertification, population increase, and extensive agricultural activity generate concern over the sustainability of the water resources of the area. The accurate estimation of the water table depth is important for an integrated groundwater resource management plan. This study focuses on the Mires basin of the Messara valley for reasons of hydro-geological data availability and geological homogeneity. The research goal is to model and map the spatial variability of the basin's groundwater level accurately. The data used in this study consist of seventy (70) piezometric head measurements for the hydrological year 2001-2002. These are unevenly distributed and mostly concentrated along a temporary river that crosses the basin. The range of piezometric heads varies from an extreme low value of 9.4 meters above sea level (masl) to 62 masl, for the wet period of the year (October to April). An initial goal of the study is to develop spatial models for the accurate generation of static maps of groundwater level. At a second stage, these maps should extend the models to dynamic (space-time) situations for the prediction of future water levels. Preliminary data analysis shows that the piezometric head variations are not normally distributed. Several methods including Box-Cox transformation and a modified version of it, transgaussian Kriging, and Gaussian anamorphosis have been used to obtain a spatial model for the piezometric head. A

  7. Development of a model to simulate groundwater inundation induced by sea-level rise and high tides in Honolulu, Hawaii.

    Science.gov (United States)

    Habel, Shellie; Fletcher, Charles H; Rotzoll, Kolja; El-Kadi, Aly I

    2017-05-01

    Many of the world's largest cities face risk of sea-level rise (SLR) induced flooding owing to their limited elevations and proximities to the coastline. Within this century, global mean sea level is expected to reach magnitudes that will exceed the ground elevation of some built infrastructure. The concurrent rise of coastal groundwater will produce additional sources of inundation resulting from narrowing and loss of the vertical unsaturated subsurface space. This has implications for the dense network of buried and low-lying infrastructure that exists across urban coastal zones. Here, we describe a modeling approach that simulates narrowing of the unsaturated space and groundwater inundation (GWI) generated by SLR-induced lifting of coastal groundwater. The methodology combines terrain modeling, groundwater monitoring, estimation of tidal influence, and numerical groundwater-flow modeling to simulate future flood scenarios considering user-specified tide stages and magnitudes of SLR. We illustrate the value of the methodology by applying it to the heavily urbanized and low-lying Waikiki area of Honolulu, Hawaii. Results indicate that SLR of nearly 1 m generates GWI across 23% of the 13 km(2) study area, threatening $5 billion of taxable real estate and 48 km of roadway. Analysis of current conditions reveals that 86% of 259 active cesspool sites in the study area are likely inundated. This suggests that cesspool effluent is currently entering coastal groundwater, which not only leads to degradation of coastal environments, but also presents a future threat to public health as GWI would introduce effluent at the ground surface. Copyright © 2017 Elsevier Ltd. All rights reserved.

  8. Anomalous frequency characteristics of groundwater levels before major earthquakes in Taiwan

    Directory of Open Access Journals (Sweden)

    C.-H. Chen

    2012-06-01

    Full Text Available Unusual decreases in water levels were consistently observed in 78% (=42/54 of the wells in the Choshuichi Alluvial Fan of central Taiwan roughly 150 days before the Chi-Chi earthquake (M = 7.6 on 20 September 1999 when the influences of barometric pressure, earth tides, precipitation and artificial pumping were removed. Variations in groundwater levels measured in the anomalous wells between 1 August 1997 and 19 September 1999, the time period covering the unusual decreases, were transferred into the frequency domain to examine anomalous frequency bands associated with the Chi-Chi earthquake. Analytical results show that amplitudes at the frequency band between 0.02 day−1 and 0.04 day−1 were generally maintained at the low stage and were enhanced in the few weeks before the Chi-Chi earthquake. Variations in amplitude within this particular frequency band were further examined in association with earthquakes (M > 6 between 1 August 1997 and 31 December 2009. Enhanced amplitude phenomena are consistently observed prior to the other two earthquakes (the Rei-Li and Ming-Jian earthquakes during the 12.5 yr, which sheds a promising light on research into precursors of strong earthquakes when combined with other geophysical observations such as geomagnetic anomalies and crustal displacements.

  9. Long-term (1930-2010) trends in groundwater levels in Texas: influences of soils, landcover and water use.

    Science.gov (United States)

    Chaudhuri, Sriroop; Ale, Srinivasulu

    2014-08-15

    Rapid groundwater depletion has raised grave concerns about sustainable development in many parts of Texas, as well as in other parts of the world. Previous hydrologic investigations on groundwater levels in Texas were conducted mostly on aquifer-specific basis, and hence lacked state-wide panoramic view. The aim of this study was to present a qualitative overview of long-term (1930-2010) trends in groundwater levels in Texas and identify spatial patterns by applying different statistical (boxplots, correlation-regression, hierarchical cluster analysis) and geospatial techniques (Moran's I, Local Indicators of Spatial Association) on 136,930 groundwater level observations from Texas Water Development Board's database. State-wide decadal median water-levels declined from about 14 m from land surface in the 1930s to about 36 m in the 2000s. Number of counties with deeper median water-levels (water-level depth>100 m) increased from 2 to 13 between 1930s and 2000s, accompanied by a decrease in number of counties having shallower median water-levels (water-level depthlandcover, geology and soil properties distinguished Texas Panhandle from GMA 8. Irrigated agriculture is the major cause of depletion in the Texas Panhandle as compared to increasing urbanization in GMA 8. Overall our study indicated that use of robust spatial and statistical methods can reveal important details about the trends in water-level changes and shed lights on the associated factors. Due to very generic nature, techniques used in this study can also be applied to other areas with similar eco-hydrologic issues to identify regions that warrant future management actions.

  10. Interim Status Groundwater Monitoring Plan for Low-Level Waste Management Areas 1 to 4, RCRA Facilities, Hanford,Washington

    Energy Technology Data Exchange (ETDEWEB)

    Dresel, P Evan

    2004-10-25

    This document describes the monitoring plan to meet the requirements for interim status groundwater monitoring at Hanford Site low-level waste burial grounds as specified by 40 CFR 265, incorporated by reference in WAC 173-303-400. The monitoring will take place at four separate low-level waste management areas in the 200-West and 200-East Areas, in the central part of the site. This plan replaces the previous monitoring plan.

  11. Influence of irrigation on the level, salinity and flow of groundwater at ...

    African Journals Online (AJOL)

    2010-03-31

    Mar 31, 2010 ... Suitable internal subsurface drainage should be cleaned, ... Keywords: Drainage, irrigation and scheduling, soil water quality, water and salt balance ..... groundwater was pumped or bailed out of the piezometers and.

  12. Groundwater Recharge Rates and Surface Runoff Response to Land Use and Land Cover Changes in Semi-arid Environments

    Science.gov (United States)

    Owuor, Steven; Butterbach-Bahl, Klaus; Guzha, Alphonce; Rufino, Mariana; Pelster, David; Díaz-Pinés, Eugenio; Breuer, Lutz; Merbold, Lutz

    2017-04-01

    Conclusive evidence and understanding of the effects of land use and land cover (LULC) on both groundwater recharge and surface runoff is critical for effective management of water resources in semi-arid region as those heavily depend on groundwater resources. However, there is limited quantitative evidence on how changes to LULC in semi-arid tropical and subtropical regions affect the subsurface components of the hydrologic cycle, particularly groundwater recharge. In this study, we reviewed a total of 27 studies (2 modelling and 25 experimental), which reported on pre- and post-land use change groundwater recharge or surface runoff magnitude, and thus allowed to quantify the response of groundwater recharge rates and runoff to LULC. Restoration of bare land induces a decrease in groundwater recharge from 42 % of precipitation to between 6 and 12 % depending on the final LULC. If forests are cleared for rangelands, groundwater recharge increases by 7.8 ± 12.6 %, while conversion to cropland or grassland results in increases of 3.4 ± 2.5 and 4.4 ± 3.3 %, respectively. Rehabilitation of bare land to cropland results in surface runoff reductions of between 5.2 and 7.3 %. The conversion of forest vegetation to managed LULC shows an increase in surface runoff from 1 to 14.1 % depending on the final LULC. Surface runoff is reduced from 2.5 to 1.1 % when grassland is converted to forest vegetation. While there is general consistency in the results from the selected case studies, we conclude that there are few experimental studies that have been conducted in tropical and subtropical semi-arid regions, despite that many people rely heavily on groundwater for their livelihoods. Therefore, there is an urgent need to increase the body of quantitative evidence given the pressure of growing human population and climate change on water resources in the region.

  13. Environmental impact of radionuclide migration in groundwater from a low-intermediate level radioactive waste repository

    Institute of Scientific and Technical Information of China (English)

    2001-01-01

    The radionuclide migration from a certain Chinese repository withlow-intermediate level radioactive solid waste is studied. The migration in groundwater is analyzed and computed in detail. Under presumption of normal releasing, or the bottom of the repository has been marinated for one month with precipitation reaching 600 mm once and a 6m aerated zone exists, a prediction for 7 radionuclides is conducted. It shows that the aerated zone is the primary barrier for migration. The migration for radionuclides 60Co, 137Cs, 90Sr, 63Ni, etc. will be retarded in it within 500 years. The concentration of 239Pu will be decreased by amount of 6 order. Only 3H and 14C can migrate through the aerated zone. The radionuclides that go through the aerated zone and enter the aquifer will exist in spring, stream and sea. Based on this, the intake dose by residents in different age group resulting from drinking contaminated spring water, eating seafood is calculated. The results showed that the impact of the repository to the key resident group is lower than the limit in national repository regulation standard. This complies with the repository management target.

  14. Simulating groundwater-induced sewer flooding

    Science.gov (United States)

    Mijic, A.; Mansour, M.; Stanic, M.; Jackson, C. R.

    2016-12-01

    During the last decade, Chalk catchments of southern England experienced severe groundwater flooding. High groundwater levels resulted in the groundwater ingress into the sewer network that led to restricted toilet use and the overflow of diluted, but untreated sewage to road surfaces, rivers and water courses. In response to these events the water and sewerage company Thames Water Utilities Ltd (TWUL) had to allocate significant funds to mitigate the impacts. It was estimated that approximately £19m was spent responding to the extreme wet weather of 2013-14, along with the use of a fleet of over 100 tankers. However, the magnitude of the event was so large that these efforts could not stop the discharge of sewage to the environment. This work presents the analysis of the risk of groundwater-induced sewer flooding within the Chalk catchment of the River Lambourn, Berkshire. A spatially distributed groundwater model was used to assess historic groundwater flood risk and the potential impacts of changes in future climate. We then linked this model to an urban groundwater model to enable us to simulate groundwater-sewer interaction in detail. The modelling setup was used to identify relationships between infiltration into sewers and groundwater levels at specific points on TWUL's sewer network, and to estimate historic and future groundwater flood risk, and how this varies across the catchment. The study showed the significance of understanding the impact of groundwater on the urban water systems, and producing information that can inform a water company's response to groundwater flood risk, their decision making process and their asset management planning. However, the knowledge gained through integrated modelling of groundwater-sewer interactions has highlighted limitations of existing approaches for the simulation of these coupled systems. We conclude this work with number of recommendations about how to improve such hydrological/sewer analysis.

  15. Simulation and assessment of groundwater flow and groundwater and surface-water exchanges in lakes of the northeast Twin Cities Metropolitan Area, Minnesota, 2003 through 2013: Chapter B of Water levels and groundwater and surface-water exchanges in lakes of the northeast Twin Cities Metropolitan Area, Minnesota, 2002 through 2015

    Science.gov (United States)

    Jones, Perry M.; Roth, Jason L.; Trost, Jared J.; Christenson, Catherine A.; Diekoff, Aliesha L.; Erickson, Melinda L.

    2017-09-05

    Water levels during 2003 through 2013 were less than mean water levels for the period 1925–2013 for several lakes in the northeast Twin Cities Metropolitan Area in Minnesota. Previous periods of low lake-water levels generally were correlated with periods with less than mean precipitation. Increases in groundwater withdrawals and land-use changes have brought into question whether or not recent (2003–13) lake-water-level declines are solely caused by decreases in precipitation. A thorough understanding of groundwater and surface-water exchanges was needed to assess the effect of water-management decisions on lake-water levels. To address this need, the U.S. Geological Survey, in cooperation with the Metropolitan Council and the Minnesota Department of Health, developed and calibrated a three-dimensional, steady-state groundwater-flow model representing 2003–13 mean hydrologic conditions to assess groundwater and lake-water exchanges, and the effects of groundwater withdrawals and precipitation on water levels of 96 lakes in the northeast Twin Cities Metropolitan Area.Lake-water budgets for the calibrated groundwater-flow model indicated that groundwater is flowing into lakes in the northeast Twin Cities Metropolitan Area and lakes are providing water to underlying aquifers. Lake-water outflow to the simulated groundwater system was a major outflow component for Big Marine Lake, Lake Elmo, Snail Lake, and White Bear Lake, accounting for 45 to 64 percent of the total outflows from the lakes. Evaporation and transpiration from the lake surface ranged from 19 to 52 percent of the total outflow from the four lakes. Groundwater withdrawals and precipitation were varied from the 2003‒13 mean values used in the calibrated model (30-percent changes in groundwater withdrawals and 5-percent changes in precipitation) for hypothetical scenarios to assess the effects of groundwater withdrawals and precipitation on water budgets and levels in Big Marine Lake, Snail Lake

  16. Ecohydrological Responses to Diversion of Groundwater: Case Study of a Deep-Rock Repository for Spent Nuclear Fuel in Sweden

    Energy Technology Data Exchange (ETDEWEB)

    Werner, Kent [EmpTec, Taeby (Sweden)], E-mail: kent.werner@emptec.se; Collinder, Per [Ekologigruppen AB, Stockholm (Sweden); Berglund, Sten [HydroResearch AB, Taeby (Sweden); Maartensson, Erik [DHI Sverige AB, Lund (Sweden)

    2013-05-15

    Planning and license applications concerning groundwater diversion in areas containing water-dependent or water-favored habitats must take into account both hydrological effects and associated ecological consequences. There is at present no established methodology to assess such ecohydrological responses. Thus, this paper describes a new stepwise methodology to assess ecohydrological responses to groundwater diversion from, e.g., water-drained pits, shafts, tunnels, and caverns in rock below the groundwater table. The methodology is illustrated using the planned deep-rock repository for spent nuclear fuel at Forsmark in central Sweden as a case study, offering access to a unique hydrological and ecological dataset. The case study demonstrates that results of ecohydrological assessments can provide useful inputs to planning of monitoring programs and mitigation measures in infrastructure projects. As a result of the assessment, artificial water supply to wetlands is planned in order to preserve biological diversity, nature values, and vulnerable species.

  17. Groundwater level and specific conductance monitoring at Marine Corps Base, Camp Lejeune, Onslow County, North Carolina, 2007-2008

    Science.gov (United States)

    McSwain, Kristen Bukowski

    2010-01-01

    The U.S. Geological Survey, in cooperation with the Marine Corps Base, Camp Lejeune, monitored water-resources conditions in the surficial, Castle Hayne, Peedee, and Black Creek aquifers in Onslow County, North Carolina, from November 2007 through September 2008. To comply with North Carolina Central Coastal Plain Capacity Use Area regulations, large-volume water suppliers in Onslow County must reduce their dependency on the Black Creek aquifer as a water-supply source and have, instead, proposed using the Castle Hayne aquifer as an alternative water-supply source. The Marine Corps Base, Camp Lejeune, uses water obtained from the unregulated surficial and Castle Hayne aquifers for drinking-water supply. Water-level data were collected and field measurements of physical properties were made at 19 wells at 8 locations spanning the Marine Corps Base, Camp Lejeune. These wells were instrumented with near real-time monitoring equipment to collect hourly measurements of water level. Additionally, specific conductance and water temperature were measured hourly in 16 of the 19 wells. Graphs are presented relating altitude of groundwater level to water temperature and specific conductance measurements collected during the study, and the relative vertical gradients between aquifers are discussed. The period-of-record normal (25th to 75th percentile) monthly mean groundwater levels at two well clusters were compared to median monthly mean groundwater levels at these same well clusters for 2008 to determine groundwater-resources conditions. In 2008, water levels were below normal in the 3 wells at one of the well clusters and were normal in 4 wells at the other cluster.

  18. Movement of a tritium plume in shallow groundwater at a legacy low-level radioactive waste disposal site in eastern Australia.

    Science.gov (United States)

    Hughes, C E; Cendón, D I; Harrison, J J; Hankin, S I; Johansen, M P; Payne, T E; Vine, M; Collins, R N; Hoffmann, E L; Loosz, T

    2011-10-01

    Between 1960 and 1968 low-level radioactive waste was buried in a series of shallow trenches near the Lucas Heights facility, south of Sydney, Australia. Groundwater monitoring carried out since the mid 1970s indicates that with the exception of tritium, no radioactivity above typical background levels has been detected outside the immediate vicinity of the trenches. The maximum tritium level detected in ground water was 390 kBq/L and the median value was 5400 Bq/L, decay corrected to the time of disposal. Since 1968, a plume of tritiated water has migrated from the disposal trenches and extends at least 100 m from the source area. Tritium in rainfall is negligible, however leachate from an adjacent and fill represents a significant additional tritium source. Study data indicate variation in concentration levels and plume distribution in response to wet and dry climatic periods and have been used to determine pathways for tritium migration through the subsurface.

  19. Assessment of fluoride level in groundwater and prevalence of dental fluorosis in Didwana block of Nagaur district, Central Rajasthan, India.

    Science.gov (United States)

    Arif, M; Husain, I; Hussain, J; Kumar, S

    2013-10-01

    In India, for the high concentration of fluoride in groundwater, people are at risk of dental fluorosis. The problem is common in various states of India. The condition in Rajasthan is worse where all districts have such a problem. To study the fluoride concentration in groundwater and prevalence of dental fluorosis in Didwana block of Nagaur district, Central Rajasthan, India. The fluoride concentration in water of 54 villages was measured electrochemically, using fluoride ion selective electrode. Dental fluorosis was assessed in 1136 people residing in study area by Dean's classification for dental fluorosis. The fluoride concentration in groundwater in studied sites ranged from 0.5 to 8.5 mg/L. The concentration of fluoride was more than the maximum permissible limit set by WHO and Bureau of Indian Standards (1 mg/L) in 48 groundwater sources. Of 1136 people studied, 788 (69.4%; 95% CI: 66.7%-72.1%) had dental fluoros---252 had mild and 74 had severe dental fluorosis. High level of fluoride in drinking water of Didwana block of Nagaur district, Central Rajasthan, India, causes dental fluorosis in most people in the region and is an important health problem that needs prompt attention.

  20. Assessment of Fluoride Level in Groundwater and Prevalence of Dental Fluorosis in Didwana Block of Nagaur District, Central Rajasthan, India

    Directory of Open Access Journals (Sweden)

    S Kumar

    2013-10-01

    Full Text Available Background: In India, for the high concentration of fluoride in groundwater, people are at risk of dental fluorosis. The problem is common in various states of India. The condition in Rajasthan is worse where all districts have such a problem.Objective: To study the fluoride concentration in groundwater and prevalence of dental fluorosis in Didwana block of Nagaur district, Central Rajasthan, India.Methods: The fluoride concentration in water of 54 villages was measured electrochemically, using fluoride ion selective electrode. Dental fluorosis was assessed in 1136 people residing in study area by Dean's classification for dental fluorosis.Results: The fluoride concentration in groundwater in studied sites ranged from 0.5 to 8.5 mg/L. The concentration of fluoride was more than the maximum permissible limit set by WHO and Bureau of Indian Standards (1 mg/L in 48 groundwater sources. Of 1136 people studied, 788 (69.4%; 95% CI: 66.7%–72.1% had dental fluorosis—252 had mild and 74 had severe dental fluorosis.Conclusion: High level of fluoride in drinking water of Didwana block of Nagaur district, Central Rajasthan, India, causes dental fluorosis in most people in the region and is an important health problem that needs prompt attention.

  1. Water levels and groundwater and surface-water exchanges in lakes of the northeast Twin Cities Metropolitan Area, Minnesota, 2002 through 2015

    Science.gov (United States)

    Jones, Perry M.; Trost, Jared J.; Erickson, Melinda L.

    2016-10-19

    OverviewThis study assessed lake-water levels and regional and local groundwater and surface-water exchanges near northeast Twin Cities Metropolitan Area lakes applying three approaches: statistical analysis, field study, and groundwater-flow modeling.  Statistical analyses of lake levels were completed to assess the effect of physical setting and climate on lake-level fluctuations of selected lakes. A field study of groundwater and surface-water interactions in selected lakes was completed to (1) estimate potential percentages of surface-water contributions to well water across the northeast Twin Cities Metropolitan Area, (2) estimate general ages for waters extracted from the wells, and (3) assess groundwater inflow to lakes and lake-water outflow to aquifers downgradient from White Bear Lake.  Groundwater flow was simulated using a steady-state, groundwater-flow model to assess regional groundwater and surface-water exchanges and the effects of groundwater withdrawals, climate, and other factors on water levels of northeast Twin Cities Metropolitan Area lakes.

  2. Response to recharge variation of thin rainwater lenses and their mixing zone with underlying saline groundwater

    Directory of Open Access Journals (Sweden)

    S. Eeman

    2012-10-01

    Full Text Available In coastal zones with saline groundwater, fresh groundwater lenses may form due to infiltration of rain water. The thickness of both the lens and the mixing zone, determines fresh water availability for plant growth. Due to recharge variation, the thickness of the lens and the mixing zone are not constant, which may adversely affect agricultural and natural vegetation if saline water reaches the root zone during the growing season. In this paper, we study the response of thin lenses and their mixing zone to variation of recharge. The recharge is varied using sinusoids with a range of amplitudes and frequencies. We vary lens characteristics by varying the Rayleigh number and Mass flux ratio of saline and fresh water, as these dominantly influence the thickness of thin lenses and their mixing zone. Numerical results show a linear relation between the normalised lens volume and the main lens and recharge characteristics, enabling an empirical approximation of the variation of lens thickness. Increase of the recharge amplitude causes increase and the increase of recharge frequency causes a decrease in the variation of lens thickness. The average lens thickness is not significantly influenced by these variations in recharge, contrary to the mixing zone thickness. The mixing zone thickness is compared to that of a Fickian mixing regime. A simple relation between the travelled distance of the centre of the mixing zone position due to variations in recharge and the mixing zone thickness is shown to be valid for both a sinusoidal recharge variation and actual records of daily recharge data. Starting from a step response function, convolution can be used to determine the effect of variable recharge in time. For a sinusoidal curve, we can determine delay of lens movement compared to the recharge curve as well as the lens amplitude, derived from the convolution integral. Together the proposed equations provide us with a first order approximation of lens

  3. Response to recharge variation of thin lenses and their mixing zone with underlying saline groundwater

    Directory of Open Access Journals (Sweden)

    S. Eeman

    2012-01-01

    Full Text Available In coastal zones with saline groundwater, fresh groundwater lenses may form due to infiltration of rain water. The thickness of both the lens and the mixing zone, determines fresh water availability for plant growth. Due to recharge variation, the thickness of the lens and the mixing zone are not constant, which may adversely affect agricultural and natural vegetation if saline water reaches the root zone during the growing season. In this paper, we study the response of thin lenses and their mixing zone to variation of recharge. The recharge is varied using sinusoids with a range of amplitudes and frequencies. We vary lens characteristics by varying the Rayleigh number and Mass flux ratio of saline and fresh water, as these dominantly influence the thickness of thin lenses and their mixing zone. Numerical results show a linear relation between the normalized lens volume and the main lens and recharge characteristics, enabling an analytical approximation of the variation of lens thickness. Increase of the recharge amplitude causes increase, and increase of recharge frequency causes decrease in the variation of lens thickness. The average lens thickness is not significantly influenced by these variations in recharge, contrary to the mixing zone thickness. The mixing zone thickness is compared to that of a Fickian mixing regime. A simple relation between the travelled distance of the center of the mixing zone position due to variations in recharge and the mixing zone thickness is shown to be valid for both a sinusoidal recharge variation and actual records of daily recharge data. Starting from a step response function, convolution can be used to determine the effect of variable recharge in time. For a sinusoidal curve, we can determine delay of lens movement compared to the recharge curve as well as the lens amplitude, derived from the convolution integral. Together the proposed equations provide us with a first order approximation of lens

  4. A new concept of irrigation response units for effective management of surface and groundwater resources: a case study from the multi-country Fergana Valley, Central Asia

    KAUST Repository

    Awan, Usman Khalid

    2016-09-09

    When estimating canal water supplies for large-scale irrigation schemes and especially in arid regions worldwide, the impact of all factors affecting the gross irrigation requirements (GIR) are not properly accounted for, which results in inefficient use of precious freshwater resources. This research shows that the concept of irrigation response units (IRU)—areas having unique combinations of factors effecting the GIR—allows for more precise estimates of GIR. An overlay analysis of soil texture and salinity, depth and salinity of groundwater, cropping patterns and irrigation methods was performed in a GIS environment, which yielded a total of 17 IRUs combinations of the Oktepa Zilol Chashmasi water consumers’ association in multi-country Fergana Valley, Central Asia. Groundwater contribution, leaching requirements, losses in the irrigation system through field application and conveyance and effective rainfall were included in GIR estimates. The GIR varied significantly among IRUs [average of 851 mm (±143 mm)] with a maximum (1051 mm) in IRU-12 and a minimum (629 mm) in IRUs-15, 16. Owing to varying groundwater levels in each IRU, the groundwater contribution played a key role in the estimation of the GIR. The maximum groundwater contribution occurred in IRUs dominated by cotton–fallow rotations as evidenced by an average value of 159 mm but a maximum of 254 mm and a minimum of 97 mm. Percolation losses depended on irrigation methods for different crops in their respective IRUs. The novel approach can guide water managers in this and similar regions to increase the accuracy of irrigation demands based on all the factor effecting the GIR. © 2016 Springer-Verlag Berlin Heidelberg

  5. Geostatistical interpolation model selection based on ArcGIS and spatio-temporal variability analysis of groundwater level in piedmont plains, northwest China.

    Science.gov (United States)

    Xiao, Yong; Gu, Xiaomin; Yin, Shiyang; Shao, Jingli; Cui, Yali; Zhang, Qiulan; Niu, Yong

    2016-01-01

    Based on the geo-statistical theory and ArcGIS geo-statistical module, datas of 30 groundwater level observation wells were used to estimate the decline of groundwater level in Beijing piedmont. Seven different interpolation methods (inverse distance weighted interpolation, global polynomial interpolation, local polynomial interpolation, tension spline interpolation, ordinary Kriging interpolation, simple Kriging interpolation and universal Kriging interpolation) were used for interpolating groundwater level between 2001 and 2013. Cross-validation, absolute error and coefficient of determination (R(2)) was applied to evaluate the accuracy of different methods. The result shows that simple Kriging method gave the best fit. The analysis of spatial and temporal variability suggest that the nugget effects from 2001 to 2013 were increasing, which means the spatial correlation weakened gradually under the influence of human activities. The spatial variability in the middle areas of the alluvial-proluvial fan is relatively higher than area in top and bottom. Since the changes of the land use, groundwater level also has a temporal variation, the average decline rate of groundwater level between 2007 and 2013 increases compared with 2001-2006. Urban development and population growth cause over-exploitation of residential and industrial areas. The decline rate of the groundwater level in residential, industrial and river areas is relatively high, while the decreasing of farmland area and development of water-saving irrigation reduce the quantity of water using by agriculture and decline rate of groundwater level in agricultural area is not significant.

  6. Maps showing ground-water levels, springs, and depth to ground water, Basin and Range Province, Texas

    Science.gov (United States)

    Brady, B.T.; Bedinger, M.S.; Mulvihill, D.A.; Mikels, John; Langer, W.H.

    1984-01-01

    This report on ground-water levels, springs, and depth to ground water in the Basin and Range province of Texas (see index map) was prepared as part of a program of the U.S. Geological Survey to identify prospective regions for further study relative to isolation of high-level nuclear waste (Bedinger, Sargent, and Reed, 1984), utilizing program guidelines defined in Sargent and Bedinger (1984). Also included in this report are selected references on pertinent geologic and hydrologic studies of the region. Other map reports in this series contain detailed data on ground-water quality, surface distribution of selected rock types, tectonic conditions, areal geophysics, Pleistocene lakes and marshes, and mineral and energy resources.

  7. Time prediction of an onset of shallow landslides based on the monitoring of the groundwater level and the surface displacement at different locations on a sandy model slope

    Science.gov (United States)

    Sasahara, Katsuo

    2016-04-01

    Location of monitoring of the deformation and the groundwater level in a slope is important for time-prediction of an onset of shallow landslides based on the monitoring. The analysis of the monitored data of the surface displacement and the groundwater level at different locations in sandy model slope under artificial rainfall was conducted in this study. The monitored data showed that the surface displacement increased with the increase of the groundwater level significantly. Then the analysis of the monitored data revealed that the relation between the surface displacement and the groundwater level can be modified as hyperbolic curve. The surface displacement grew larger and maximum groundwater level was smaller at farther location from the toe of the slope. Time-prediction of an onset of a landslide based on the monitored data at different location on the slope was proposed as following procedures. (1) To make a regression equation for the relation between the surface displacement and the groundwater level based on the monitored data at any time before the failure, (2) To make a regression equation for the relation between the time and the groundwater level based on the same data with (1), and (3) To incorporate the equation for the relation between the time and the groundwater level into that between the surface displacement and the groundwater level to derive the time - the surface displacement relation. (4) To derive the time - the inverse of the surface displacement velocity from the equation for the time - the surface displacement relation. The equation for the time - the surface displacement and the equation for the time - the inverse of the surface displacement velocity could simulate the actual phenomena of the slope well based on the monitored data at any location on the model slope.

  8. 高精度地下水位监测仪%High Precision Groundwater Level Monitor

    Institute of Scientific and Technical Information of China (English)

    钟佳迅; 庹先国; 王洪辉; 张兆义; 张贵宇

    2012-01-01

    Through studying the change of groundwater on the influence of the geological hazards, such as landslide, a high precision groundwater level monitor was designed. The monitor took advantage of static-pressure water level sensor to get ground-water level information. By means of sophisticated I/V conversion, high precision A/D conversion, high stability reference voltage and cooperating with curve fitting method, it realized the high precision collection of groundwater level information, and the system error was less than 1 mm. In the actual application, the instrument highlighted its advantages such as high precision, stable performance, small volume,installation flexible,convenient operation,etc. The monitor can be applied to all kinds of monitoring wells very well,and used in geological disaster monitoring.%通过地下水位变化对滑坡等地质灾害的影响研究,设计了一种高精度地下水位监测仪器.仪器采用静压力式水位传感器获取地下水位信息,通过精密I/V转换、高精度A/D转换及高稳定性基准电压,并配合曲线拟合方法,实现了地下水位信息的高精度采集,误差≤1 mm.在实际应用中,仪器突出了精度高、性能稳定、体积小、安装灵活、操作方便等优点,对各类监测井具有很强的适应性,适合用于地质灾害监测.

  9. Assessment of the impact of sea-level rise due to climate change on coastal groundwater discharge.

    Science.gov (United States)

    Masciopinto, Costantino; Liso, Isabella Serena

    2016-11-01

    An assessment of sea intrusion into coastal aquifers as a consequence of local sea-level rise (LSLR) due to climate change was carried out at Murgia and Salento in southern Italy. The interpolation of sea-level measurements at three tide-gauge stations was performed during the period of 2000 to 2014. The best fit of measurements shows an increasing rate of LSLR ranging from 4.4mm/y to 8.8mm/y, which will result in a maximum LSLR of approximately 2m during the 22nd century. The local rate of sea-level rise matches recent 21st and 22nd century projections of mean global sea-level rise determined by other researchers, which include increased melting rates of the Greenland and Antarctic ice sheets, the effect of ocean thermal expansion, the melting of glaciers and ice caps, and changes in the quantity of stored land water. Subsequently, Ghyben-Herzberg's equation for the freshwater/saltwater interface was rewritten in order to determine the decrease in groundwater discharge due to the maximum LSLR. Groundwater flow simulations and ArcGIS elaborations of digital elevation models of the coast provided input data for the Ghyben-Herzberg calculation under the assumption of head-controlled systems. The progression of seawater intrusion due to LSLR suggests an impressive depletion of available groundwater discharge during the 22nd century, perhaps as much as 16.1% of current groundwater pumping for potable water in Salento. Copyright © 2016 Elsevier B.V. All rights reserved.

  10. Numerical study on the responses of groundwater and strata to pumping and recharge in a deep confined aquifer

    Science.gov (United States)

    Zhang, Yang-Qing; Wang, Jian-Hua; Chen, Jin-Jian; Li, Ming-Guang

    2017-05-01

    Groundwater drawdown and strata settlements induced by dewatering in confined aquifers can be relieved by artificial recharge. In this study, numerical simulations of a field multi-well pumping-recharge test in a deep confined aquifer are conducted to analyze the responses of groundwater and strata to pumping and recharge. A three-dimensional numerical model is developed in a finite-difference software, which considers the fluid-mechanical interaction using the Biot consolidation theory. The predicted groundwater drawdown and ground settlements are compared to the measured data to confirm the validation of the numerical analysis of the pumping and recharge. Both numerical results and measured data indicate that the effect of recharge on controlling the groundwater drawdown and strata settlements correlates with the injection rate and well arrangements. Since the groundwater drawdown induced by pumping can be controlled by artificial recharge, soil compression can be relieved by reducing the changes of effective stress of the soils. Consequently, strata settlement induced by pumping can be relieved by artificial recharge and ground settlements can be eliminated if an appropriate injection rate and well arrangement are being determined. Moreover, the changes of the pore pressure and seepage force induced by pumping and recharge will also result in significant horizontal deformations in the strata near the recharge wells.

  11. Spatial variability of the response to climate change in regional groundwater systems -- examples from simulations in the Deschutes Basin, Oregon

    Science.gov (United States)

    Waibel, Michael S.; Gannett, Marshall W.; Chang, Heejun; Hulbe, Christina L.

    2013-01-01

    We examine the spatial variability of the response of aquifer systems to climate change in and adjacent to the Cascade Range volcanic arc in the Deschutes Basin, Oregon using downscaled global climate model projections to drive surface hydrologic process and groundwater flow models. Projected warming over the 21st century is anticipated to shift the phase of precipitation toward more rain and less snow in mountainous areas in the Pacific Northwest, resulting in smaller winter snowpack and in a shift in the timing of runoff to earlier in the year. This will be accompanied by spatially variable changes in the timing of groundwater recharge. Analysis of historic climate and hydrologic data and modeling studies show that groundwater plays a key role in determining the response of stream systems to climate change. The spatial variability in the response of groundwater systems to climate change, particularly with regard to flow-system scale, however, has generally not been addressed in the literature. Here we simulate the hydrologic response to projected future climate to show that the response of groundwater systems can vary depending on the location and spatial scale of the flow systems and their aquifer characteristics. Mean annual recharge averaged over the basin does not change significantly between the 1980s and 2080s climate periods given the ensemble of global climate models and emission scenarios evaluated. There are, however, changes in the seasonality of groundwater recharge within the basin. Simulation results show that short-flow-path groundwater systems, such as those providing baseflow to many headwater streams, will likely have substantial changes in the timing of discharge in response changes in seasonality of recharge. Regional-scale aquifer systems with flow paths on the order of many tens of kilometers, in contrast, are much less affected by changes in seasonality of recharge. Flow systems at all spatial scales, however, are likely to reflect

  12. A dynamically-coupled groundwater, land surface and regional climate model to predict seasonal watershed flow and groundwater response, FINAL LDRD REPORT.

    Energy Technology Data Exchange (ETDEWEB)

    Maxwell, R; Kollet, S; Chow, F; Granvold, P; Duan, Q

    2007-02-23

    This final report is organized in four sections. Section 1 is the project summary (below), Section 2 is a submitted manuscript that describes the offline, or spinup simulations in detail, Section 3 is also a submitted manuscript that describes the online, or fully-coupled simulations in detail and Section 3, which is report that describes work done via a subcontract with UC Berkeley. The goal of this project was to develop and apply a coupled regional climate, land-surface, groundwater flow model as a means to further understand important mass and energy couplings between regional climate, the land surface, and groundwater. The project involved coupling three distinct submodels that are traditionally used independently with abstracted and potentially oversimplified (inter-model) boundary conditions. This coupled model lead to (1) an improved understanding of the sensitivity and importance of coupled physical processes from the subsurface to the atmosphere; (2) a new tool for predicting hydrologic conditions (rainfall, temperature, snowfall, snowmelt, runoff, infiltration and groundwater flow) at the watershed scale over a range of timeframes; (3) a simulation of hydrologic response of a characteristic watershed that will provide insight into the certainty of hydrologic forecasting, dominance and sensitivity of groundwater dynamics on land-surface fluxes; and (4) a more realistic model representation of weather predictions, precipitation and temperature, at the regional scale. Regional climate models are typically used for the simulation of weather, precipitation and temperature behavior over 10-1000 km domains for weather or climate prediction purposes, and are typically driven by boundary conditions derived from global climate models (GCMs), observations or both. The land or ocean surface typically represents a bottom boundary condition of these models, where important mass (water) and energy fluxes are approximated. The viability and influence of these

  13. A dynamically-coupled groundwater, land surface and regional climate model to predict seasonal watershed flow and groundwater response, FINAL LDRD REPORT.

    Energy Technology Data Exchange (ETDEWEB)

    Maxwell, R; Kollet, S; Chow, F; Granvold, P; Duan, Q

    2007-02-23

    This final report is organized in four sections. Section 1 is the project summary (below), Section 2 is a submitted manuscript that describes the offline, or spinup simulations in detail, Section 3 is also a submitted manuscript that describes the online, or fully-coupled simulations in detail and Section 3, which is report that describes work done via a subcontract with UC Berkeley. The goal of this project was to develop and apply a coupled regional climate, land-surface, groundwater flow model as a means to further understand important mass and energy couplings between regional climate, the land surface, and groundwater. The project involved coupling three distinct submodels that are traditionally used independently with abstracted and potentially oversimplified (inter-model) boundary conditions. This coupled model lead to (1) an improved understanding of the sensitivity and importance of coupled physical processes from the subsurface to the atmosphere; (2) a new tool for predicting hydrologic conditions (rainfall, temperature, snowfall, snowmelt, runoff, infiltration and groundwater flow) at the watershed scale over a range of timeframes; (3) a simulation of hydrologic response of a characteristic watershed that will provide insight into the certainty of hydrologic forecasting, dominance and sensitivity of groundwater dynamics on land-surface fluxes; and (4) a more realistic model representation of weather predictions, precipitation and temperature, at the regional scale. Regional climate models are typically used for the simulation of weather, precipitation and temperature behavior over 10-1000 km domains for weather or climate prediction purposes, and are typically driven by boundary conditions derived from global climate models (GCMs), observations or both. The land or ocean surface typically represents a bottom boundary condition of these models, where important mass (water) and energy fluxes are approximated. The viability and influence of these

  14. Estimating seepage flux from ephemeral stream channels using surface water and groundwater level data

    Science.gov (United States)

    Noorduijn, Saskia L.; Shanafield, Margaret; Trigg, Mark A.; Harrington, Glenn A.; Cook, Peter G.; Peeters, L.

    2014-02-01

    Seepage flux from ephemeral streams can be an important component of the water balance in arid and semiarid regions. An emerging technique for quantifying this flux involves the measurement and simulation of a flood wave as it moves along an initially dry channel. This study investigates the usefulness of including surface water and groundwater data to improve model calibration when using this technique. We trialed this approach using a controlled flow event along a 1387 m reach of artificial stream channel. Observations were then simulated using a numerical model that combines the diffusion-wave approximation of the Saint-Vénant equations for streamflow routing, with Philip's infiltration equation and the groundwater flow equation. Model estimates of seepage flux for the upstream segments of the study reach, where streambed hydraulic conductivities were approximately 101 m d-1, were on the order of 10-4 m3 d-1 m-2. In the downstream segments, streambed hydraulic conductivities were generally much lower but highly variable (˜10-3 to 10-7 m d-1). A Latin Hypercube Monte Carlo sensitivity analysis showed that the flood front timing, surface water stage, groundwater heads, and the predicted streamflow seepage were most influenced by specific yield. Furthermore, inclusion of groundwater data resulted in a higher estimate of total seepage estimates than if the flood front timing were used alone.

  15. Characterizing the interaction of groundwater and surface water in the karst aquifer of Fangshan, Beijing (China)

    Science.gov (United States)

    Chu, Haibo; Wei, Jiahua; Wang, Rong; Xin, Baodong

    2016-12-01

    Correct understanding of groundwater/surface-water (GW-SW) interaction in karst systems is of greatest importance for managing the water resources. A typical karst region, Fangshan in northern China, was selected as a case study. Groundwater levels and hydrochemistry analyses, together with isotope data based on hydrogeological field investigations, were used to assess the GW-SW interaction. Chemistry data reveal that water type and the concentration of cations in the groundwater are consistent with those of the surface water. Stable isotope ratios of all samples are close to the local meteoric water line, and the 3H concentrations of surface water and groundwater samples are close to that of rainfall, so isotopes also confirm that karst groundwater is recharged by rainfall. Cross-correlation analysis reveals that rainfall leads to a rise in groundwater level with a lag time of 2 months and groundwater exploitation leads to a fall within 1 month. Spectral analysis also reveals that groundwater level, groundwater exploitation and rainfall have significantly similar response periods, indicating their possible inter-relationship. Furthermore, a multiple nonlinear regression model indicates that groundwater level can be negatively correlated with groundwater exploitation, and positively correlated with rainfall. The overall results revealed that groundwater level has a close correlation with groundwater exploitation and rainfall, and they are indicative of a close hydraulic connection and interaction between surface water and groundwater in this karst system.

  16. Characterizing the interaction of groundwater and surface water in the karst aquifer of Fangshan, Beijing (China)

    Science.gov (United States)

    Chu, Haibo; Wei, Jiahua; Wang, Rong; Xin, Baodong

    2017-03-01

    Correct understanding of groundwater/surface-water (GW-SW) interaction in karst systems is of greatest importance for managing the water resources. A typical karst region, Fangshan in northern China, was selected as a case study. Groundwater levels and hydrochemistry analyses, together with isotope data based on hydrogeological field investigations, were used to assess the GW-SW interaction. Chemistry data reveal that water type and the concentration of cations in the groundwater are consistent with those of the surface water. Stable isotope ratios of all samples are close to the local meteoric water line, and the 3H concentrations of surface water and groundwater samples are close to that of rainfall, so isotopes also confirm that karst groundwater is recharged by rainfall. Cross-correlation analysis reveals that rainfall leads to a rise in groundwater level with a lag time of 2 months and groundwater exploitation leads to a fall within 1 month. Spectral analysis also reveals that groundwater level, groundwater exploitation and rainfall have significantly similar response periods, indicating their possible inter-relationship. Furthermore, a multiple nonlinear regression model indicates that groundwater level can be negatively correlated with groundwater exploitation, and positively correlated with rainfall. The overall results revealed that groundwater level has a close correlation with groundwater exploitation and rainfall, and they are indicative of a close hydraulic connection and interaction between surface water and groundwater in this karst system.

  17. Hydrogeology, groundwater levels, and generalized potentiometric-surface map of the Green River Basin lower Tertiary aquifer system, 2010–14, in the northern Green River structural basin

    Science.gov (United States)

    Bartos, Timothy T.; Hallberg, Laura L.; Miller, Cheryl E.

    2015-07-14

    In cooperation with the Bureau of Land Management, groundwater levels in wells located in the northern Green River Basin in Wyoming, an area of ongoing energy development, were measured by the U.S. Geological Survey from 2010 to 2014. The wells were completed in the uppermost aquifers of the Green River Basin lower Tertiary aquifer system, which is a complex regional aquifer system that provides water to most wells in the area. Except for near perennial streams, groundwater-level altitudes in most aquifers generally decreased with increasing depth, indicating a general downward potential for groundwater movement in the study area. Drilled depth of the wells was observed as a useful indicator of depth to groundwater such that deeper wells typically had a greater depth to groundwater. Comparison of a subset of wells included in this study that had historical groundwater levels that were measured during the 1960s and 1970s and again between 2012 and 2014 indicated that, overall, most of the wells showed a net decline in groundwater levels.

  18. Long-Term Oil Pollution and In Situ Microbial Response of Groundwater in Northwest China.

    Science.gov (United States)

    Sun, Yujiao; Lu, Sidan; Zhao, Xiaohui; Ding, Aizhong; Wang, Lei

    2017-05-01

    Potential threats exist where groundwater is polluted by high concentrations of oil compounds (980.20 mg L(-1) the highest TPHs). An abandoned petrochemical plant in Lanzhou City, where long-term petrochemical products leakage contaminated the groundwater, was used as a field site in this study. To determine the extent of pollution and find an effective solution, chemical techniques combined with molecular biological techniques were used to survey the migration and decomposition of pollutants. Moreover, Illumina Sequencing was employed to reveal the microbial changes of different sites. Light-chain alkanes (mostly C6-C9), most benzene compounds, and some polycyclic aromatic hydrocarbons (naphthalene, 2-methylnaphthalene) mainly polluted the source. C29 to C36 and chlorobenzenes (hexachlorocyclohexane) polluted the secondary polluted sites. Moreover, chloralkane (trichloroethane and dichloroethane), benzene derivatives (trimethylbenzene and butylbenzene), and PAHs (fluorene and phenanthrene) were present in the other longtime-contaminated water. The bacterial genera are closely related with the chemical matters, and different groups of microorganisms gather in the sample sites that are polluted with different kinds of oil. The biodiversity and abundance of observed species change with pollution conditions. The dominant phyla (81%) of the bacterial community structure are Proteobacteria (62.2% of the total microbes), Bacteroidetes (8.85%), Actinobacteria (6.70%), and Choloroflexi (3.03%). Pseudomonadaceae is significant in the oil-polluted source and Comamonadaceae is significant in the secondary polluted (migrated oil) sample; these two genera are natural decomposers of refractory matters. Amycolatopsis, Rhodocyclaceae, Sulfurimonas, and Sulfuricurvum are the dominant genera in the long-migrated oil-polluted samples. Bioavailability of the oil-contaminated place differs with levels of pollution and cleaning the worse-polluted sites by microbes is more difficult.

  19. Geospatial Data Used in Water-Level and Land-Subsidence Studies in the Mojave River and Morongo Groundwater Basins for 2008

    Data.gov (United States)

    U.S. Geological Survey, Department of the Interior — During 2008, the U.S. Geological Survey and other agencies made approximately 2,500 water-level measurements in the Mojave River and Morongo groundwater basins....

  20. Geospatial Data Used in Water-Level and Land-Subsidence Studies in the Mojave River and Morongo Groundwater Basins for 2006

    Data.gov (United States)

    U.S. Geological Survey, Department of the Interior — During 2006, the U.S. Geological Survey and other agencies made approximately 2,500 water-level measurements in the Mojave River and Morongo ground-water basins....

  1. Response to recharge variation of thin rainwater lenses and their mixing zone with underlying saline groundwater

    NARCIS (Netherlands)

    Eeman, S.; Zee, van der S.E.A.T.M.; Leijnse, A.; Louw, de P.G.B.; Maas, C.

    2012-01-01

    In coastal zones with saline groundwater, fresh groundwater lenses may form due to infiltration of rain water. The thickness of both the lens and the mixing zone, determines fresh water availability for plant growth. Due to recharge variation, the thickness of the lens and the mixing zone are not co

  2. The role of bedrock groundwater in rainfall-runoff response at hillslope and catchment scales

    Science.gov (United States)

    C. Gabrielli; J.J. McDonnell; W.T. Jarvis

    2012-01-01

    Bedrock groundwater dynamics in headwater catchments are poorly understood and poorly characterized. Direct hydrometric measurements have been limited due to the logistical challenges associated with drilling through hard rock in steep, remote and often roadless terrain. We used a new portable bedrock drilling system to explore bedrock groundwater dynamics aimed at...

  3. A technique for estimating ground-water levels at sites in Rhode Island from observation-well data

    Science.gov (United States)

    Socolow, Roy S.; Frimpter, Michael H.; Turtora, Michael; Bell, Richard W.

    1994-01-01

    Estimates of future high, median, and low ground- water levels are needed for engineering and architectural design decisions and for appropriate selection of land uses. For example, the failure of individual underground sewage-disposal systems due to high ground-water levels can be prevented if accurate water-level estimates are available. Estimates of extreme or average conditions are needed because short duration preconstruction obser- vations are unlikely to be adequately represen- tative. Water-level records for 40 U.S. Geological Survey observation wells in Rhode Island were used to describe and interpret water-level fluctuations. The maximum annual range of water levels average about 6 feet in sand and gravel and 11 feet in till. These data were used to develop equations for estimating future high, median, and low water levels on the basis of any one measurement at a site and records of water levels at observation wells used as indexes. The estimating technique relies on several assumptions about temporal and spatial variations: (1) Water levels will vary in the future as they have in the past, (2) Water levels fluctuate seasonally (3) Ground-water fluctuations are dependent on site geology, and (4) Water levels throughout Rhode Island are subject to similar precipitation and climate. Comparison of 6,697 estimates of high, median, and low water levels (depth to water level exceeded 95, 50, and 5 percent of the time, respectively) with the actual measured levels exceeded 95, 50, and 5 percent of the time at 14 sites unaffected by pumping and unknown reasons, yielded mean squared errors ranging from 0.34 to 1.53 square feet, 0.30 to 1.22 square feet, and 0.32 to 2.55 square feet, respectively. (USGS)

  4. Groundwater level forecasting using an artificial neural network trained with particle swarm optimization.

    Science.gov (United States)

    Tapoglou, E.; Trichakis, I. C.; Dokou, Z.; Karatzas, G. P.

    2012-04-01

    period is minimal. Finally, climate change scenarios were examined, based on the prediction that on the island of Crete during the period of 2010-2040, it will be a 12(±25)% average reduction in precipitation and a 1.9(±0.9)oC increase in mean temperature (Tsanis et al., 2011). In order to study these scenarios, data time series were created for the period 2010-2020, using a stochastic weather generator for three cases (best, worst and average case scenarios). The prediction results indicate a significant negative effect on the groundwater level only for the worst case scenario (37% reduction in precipitation), while in the other cases the results vary from neutral to positive.

  5. Relation of hydrologic processes to groundwater and surface-water levels and flow directions in a dune-beach complex at Indiana Dunes National Lakeshore and Beverly Shores, Indiana

    Science.gov (United States)

    Buszka, Paul M.; Cohen, David A.; Lampe, David C.; Pavlovic, Noel B.

    2011-01-01

    Shores. Perennial mounding of the water table in the surficial aquifer indicates that the recharge that created the water-table mound originates within the dune-beach complex and not through flow from the adjacent hydrologic boundaries: the restored wetland, Lake Michigan, and Derby Ditch. Infiltrating precipitation causes most seasonal and episodic rises in groundwater levels beneath the dune-beach complex. Groundwater-level fluctuations lasting days to weeks in the dune-beach complex in 2008-9 were superimposed on a seasonal high water-table altitude that began with the recharge from snowmelt and rain in February 2009 and maintained through July 2009. Increases in water-table-mound altitude under the dune-beach complex recurred in 2008-9 in response to the largest rain events of 1 inch or more and to snowmelt. Smaller, shorter-term rises in water level after individual rain events persisted over hours to less than 1 week. Groundwater-level fluctuations varied over a relatively narrow range of about 2 to 3 feet, with no net fluctuations greater than 4 feet. Groundwater levels in or near low parts of the dune-beach complex were frequently within 0 to 6 feet of the land surface and indicate the potential for groundwater flooding. Groundwater-level gradients from the water-table mound to wells next to surface-water discharges increase after rainfall and snowmelt events and recede slowly as groundwater discharges from the aquifer. Evapotranspiration is responsible for part of the general pattern of decreasing water-table altitudes observed from May to August 2009. Rapid water-level rises in the restored wetland after precipitation do not likely have an effect on groundwater flooding elsewhere in the dune-beach complex. Surface-water-level fluctuations during this study generally varied over a narrower range, approximately from 1 to 1.5 feet, as compared with groundwater fluctuations, except after a very large, 10.77-inch rainfall. Time-delayed and smaller groundwater-level

  6. Functional gene array-based analysis of microbial community structure in groundwaters with a gradient of contaminant levels

    Energy Technology Data Exchange (ETDEWEB)

    Waldron, P.J.; Wu, L.; Van Nostrand, J.D.; Schadt, C.W.; Watson, D.B.; Jardine, P.M.; Palumbo, A.V.; Hazen, T.C.; Zhou, J.

    2009-06-15

    To understand how contaminants affect microbial community diversity, heterogeneity, and functional structure, six groundwater monitoring wells from the Field Research Center of the U.S. Department of Energy Environmental Remediation Science Program (ERSP; Oak Ridge, TN), with a wide range of pH, nitrate, and heavy metal contamination were investigated. DNA from the groundwater community was analyzed with a functional gene array containing 2006 probes to detect genes involved in metal resistance, sulfate reduction, organic contaminant degradation, and carbon and nitrogen cycling. Microbial diversity decreased in relation to the contamination levels of the wells. Highly contaminated wells had lower gene diversity but greater signal intensity than the pristine well. The microbial composition was heterogeneous, with 17-70% overlap between different wells. Metal-resistant and metal-reducing microorganisms were detected in both contaminated and pristine wells, suggesting the potential for successful bioremediation of metal-contaminated groundwaters. In addition, results of Mantel tests and canonical correspondence analysis indicate that nitrate, sulfate, pH, uranium, and technetium have a significant (p < 0.05) effect on microbial community structure. This study provides an overall picture of microbial community structure in contaminated environments with functional gene arrays by showing that diversity and heterogeneity can vary greatly in relation to contamination.

  7. Exact electromagnetic response of Landau level electrons

    Science.gov (United States)

    Nguyen, Dung Xuan; Gromov, Andrey

    2017-02-01

    We present a simple method that allows us to calculate the electromagnetic response of noninteracting electrons in a strong magnetic field to arbitrary order in the gradients of external electric and magnetic fields. We illustrate the method on both nonrelativistic and massless Dirac electrons filling N Landau levels. First, we derive an exact relation between the electromagnetic response of the nonrelativistic and Dirac electrons in the lowest Landau level. Next, we obtain a closed form expression for the polarization operator in the large-N (or weak magnetic field) limit. We explicitly show that in the large-N limit the random phase approximation (RPA) computation of the polarization tensor agrees—in leading and subleading order in N —with a Fermi liquid computation to all orders in the gradient expansion and for arbitrary value of the g factor. Finally, we show that in the large-N limit the nonrelativistic polarization tensor agrees with Dirac's in the leading and subleading orders in N , provided that the Berry phase of the Dirac cone is taken into account via replacement N ⟶N +1 /2 .

  8. Exact Electromagnetic Response of Landau Level Electrons

    CERN Document Server

    Nguyen, Dung Xuan

    2016-01-01

    We present a simple method that allows to calculate the electromagnetic response of non-interacting electrons in strong magnetic field to arbitrary order in the gradients of external electric and magnetic fields. We illustrate the method on both non-relativistic and massless Dirac electrons filling $N$ Landau levels. First, we derive an exact relation between the electromagnetic response of the non-relativistic and Dirac electrons in the lowest Landau level. Next, we obtain a closed form expression for the polarization operator in the large $N$ (or weak magnetic field) limit. We explicitly show that in the large $N$ limit the random phase approximation (RPA) computation of the polarization tensor agrees - in leading and sub-leading order in $N$ - with a Fermi liquid computation to {\\it all} orders in the gradient expansion and for arbitrary value of the $\\mathrm{g}$-factor. Finally, we show that in the large $N$ limit the non-relativistic polarization tensor agrees with Dirac's in the leading and sub-leading ...

  9. Enhancing arsenic removal from groundwater at household level with naturally occurring iron

    Directory of Open Access Journals (Sweden)

    Anitha Kumari Sharma

    2016-06-01

    Full Text Available A supply of drinking water low in Arsenic (As prevents arsenic poisoning. The presence of high concentrations of iron (Fe in groundwater under the alluvial plains of the large rivers in Southeast Asia is a prerequisite for the simple removal of As. This study investigated the mechanisms and possibilities for enhancing As removal with naturally occurring Fe in a reliable, low cost and sustainable way. The results of the study show that As removal with Fe is greatly enhanced by the addition of an oxidizing agent (preferably KMnO4 immediately after the pumping of groundwater. Further enhancement of As removal in the presence of Fe can be achieved by adding a small volume of a concentrated basic solution of MnO4- and AlO2-, which has a combined oxidation, coagulation and buffering capacity. Best results were obtained when this solution was mixed with the groundwater immediately after its pumping until a pale pink color appeared. Maximum required reaction time was 10 minutes and subsequent filtration of the water was able to reduce the As concentration to near zero. Concentrations of MnO4- and AlO2- can be varied in the solution to achieve sufficient As removal to suit different Fe/As ratios and the presence of interfering co-occurring anions.

  10. Groundwater subsidies and penalties to corn yield

    Science.gov (United States)

    Zipper, S. C.; Booth, E.; Loheide, S. P.

    2013-12-01

    Proper water management is critical to closing yield gaps (observed yield below potential yield) as global populations continue to expand. However, the impacts of shallow groundwater on crop production and surface processes are poorly understood. The presence of groundwater within or just below the root zone has the potential to cause (via oxygen stress in poorly drained soils) or eliminate (via water supply in dry regions) yield gaps. The additional water use by a plant in the presence of shallow groundwater, compared to free drainage conditions, is called the groundwater subsidy; the depth at which the groundwater subsidy is greatest is the optimal depth to groundwater (DTGW). In wet years or under very shallow water table conditions, the groundwater subsidy is likely to be negative due to increased oxygen stress, and can be thought of as a groundwater penalty. Understanding the spatial dynamics of groundwater subsidies/penalties and how they interact with weather is critical to making sustainable agricultural and land-use decisions under a range of potential climates. Here, we examine patterns of groundwater subsidies and penalties in two commercial cornfields in the Yahara River Watershed, an urbanizing agricultural watershed in south-central Wisconsin. Water table levels are generally rising in the region due to a long-term trend of increasing precipitation over the last several decades. Biophysical indicators tracked throughout both the 2012 and 2013 growing seasons show a strong response to variable groundwater levels on a field scale. Sections of the field with optimal DTGW exhibit consistently higher stomatal conductance rates, taller canopies and higher leaf area index, higher ET rates, and higher pollination success rates. Patterns in these biophysical lines of evidence allow us to pinpoint specific periods within the growing season that plants were experiencing either oxygen or water stress. Most importantly, groundwater subsidies and penalties are

  11. Linking soil moisture balance and source-responsive preferential flow models for estimating groundwater recharge

    Science.gov (United States)

    Cuthbert, M. O.; Mackay, R.; Nimmo, J. R.

    2012-04-01

    Results are presented of a detailed study into the vadose zone and shallow water table hydrodynamics of a fieldsite in Shropshire, UK. Tensiometry reveals that the loamy sand topsoil wets up via macropore flow and subsequent redistribution of moisture into the soil matrix. However, recharge does not occur until near-positive pressures are achieved at the top of the glaciofluvial outwash material that underlies the topsoil, about 1 m above the water table. Once this occurs, very rapid water table rises follow. This threshold behaviour is attributed to the vertical discontinuity in the macropore system due to seasonal ploughing of the topsoil, and a lower permeability plough/iron pan restricting matrix flow between the topsoil and the lower outwash deposits. Thus, although the wetting process in the topsoil is highly complex, a soil moisture balance model (SMBM) is shown to be skilful in predicting the initiation of preferential flow from the base of the topsoil into the lower outwash horizon. The rapidity of the response at the water table suggests that Stokes type film flow rather than Richards type capillarity dominated flow is occurring and this conjecture is tested using a range of numerical models. A variation of the source-responsive model proposed by Nimmo (2010) is shown to reproduce the observed water table dynamics well, when linked to a SMBM as the source of recharge from the topsoil. The results reveal new insights into preferential flow processes in cultivated soils. If the conceptual and numerical models can be shown to be transferable to other ploughed soils, it promises to be a very useful and practical approach to accounting for preferential flow in studies of groundwater recharge estimation. Nimmo, J. R. (2010). Theory for Source-Responsive and Free-Surface Film Modeling of Unsaturated Flow. Vadose Zone Journal, 9, 295-306.

  12. Response of Groundwater table to Eucalyptus Plantations in a Tropical Monsoon Climate, Lake Tana Basin, Ethiopia

    Science.gov (United States)

    Enku, Temesgen; Melesse, Assefa; Ayana, Essaya; Tilahun, Seifu; Abate, Mengiste; Steenhuis, Tammo

    2017-04-01

    Given the increasing demand for water resources and the need for better management of regional water resources, it is essential to quantify the groundwater use by phreatophytes in tropical monsoon climates. Phreatophytes, like eucalyptus plantations are reported to be a groundwater sink and it could significantly affect the regional groundwater resources. In our study, the consumptive groundwater use of a closed eucalyptus plantation was calculated based on the diurnal water table fluctuations observed in monitoring wells for two dry monsoon phases in the Fogera plain, northwest of Ethiopia. Automated recorders were installed to monitor the hourly groundwater table fluctuations. The groundwater table fluctuates from maximum at early in the morning to minimum in the evening daily and generally declined linearly during the dry phase averaging 3.1 cm/day during the two year period under the eucalyptus plantations. The hourly eucalypts transpiration rate over the daylight hours follows the daily solar irradiance curve for clear sky days. It is minimal during the night and reaches maximum of 1.65mm/hour at mid-day. The evapotranspiration from the groundwater by eucalyptus plantations during the dry phases was estimated at about 2300mm from October 1 to 31 May, in 2015 compared to about 900mm without eucalyptus trees. The average daily evapotranspiration was 9.6mm. This is almost twice of the reference evapotranspiration in the area and 2.5 times the actual rate under fallow agricultural fields. Thus, water resources planning and management in the region needs to consider the effect of eucalyptus plantations on the availability of groundwater resources in the highlands of Ethiopia. Key words: Eucalyptus, Evapotranspiration, Groundwater, Ethiopia, Lake Tana

  13. Electrical resistivity dynamics beneath a fractured sedimentary bedrock riverbed in response to temperature and groundwater-surface water exchange

    Science.gov (United States)

    Steelman, Colby M.; Kennedy, Celia S.; Capes, Donovan C.; Parker, Beth L.

    2017-06-01

    Bedrock rivers occur where surface water flows along an exposed rock surface. Fractured sedimentary bedrock can exhibit variable groundwater residence times, anisotropic flow paths, and heterogeneity, along with diffusive exchange between fractures and rock matrix. These properties of the rock will affect thermal transients in the riverbed and groundwater-surface water exchange. In this study, surface electrical methods were used as a non-invasive technique to assess the scale and temporal variability of riverbed temperature and groundwater-surface water interaction beneath a sedimentary bedrock riverbed. Conditions were monitored at a semi-daily to semi-weekly interval over a full annual period that included a seasonal freeze-thaw cycle. Surface electromagnetic induction (EMI) and electrical resistivity tomography (ERT) methods captured conditions beneath the riverbed along a pool-riffle sequence of the Eramosa River in Canada. Geophysical datasets were accompanied by continuous measurements of aqueous specific conductance, temperature, and river stage. Time-lapse vertical temperature trolling within a lined borehole adjacent to the river revealed active groundwater flow zones along fracture networks within the upper 10 m of rock. EMI measurements collected during cooler high-flow and warmer low-flow periods identified a spatiotemporal riverbed response that was largely dependent upon riverbed morphology and seasonal groundwater temperature. Time-lapse ERT profiles across the pool and riffle sequence identified seasonal transients within the upper 2 and 3 m of rock, respectively, with spatial variations controlled by riverbed morphology (pool versus riffle) and dominant surficial rock properties (competent versus weathered rock rubble surface). While the pool and riffle both exhibited a dynamic resistivity through seasonal cooling and warming cycles, conditions beneath the pool were more variable, largely due to the formation of river ice during the winter season

  14. Groundwater-abstraction induced land subsidence and groundwater regulation in the North China Plain

    Science.gov (United States)

    Guo, H.; Wang, L.; Cheng, G.; Zhang, Z.

    2015-11-01

    Land subsidence can be induced when various factors such as geological, and hydrogeological conditions and intensive groundwater abstraction combine. The development and utilization of groundwater in the North China Plain (NCP) bring great benefits, and at the same time have led to a series of environmental and geological problems accompanying groundwater-level declines and land subsidence. Subsidence occurs commonly in the NCP and analyses show that multi-layer aquifer systems with deep confined aquifers and thick compressible clay layers are the key geological and hydrogeological conditions responsible for its development in this region. Groundwater overdraft results in aquifer-system compaction, resulting in subsidence. A calibrated, transient groundwater-flow numerical model of the Beijing plain portion of the NCP was developed using MODFLOW. According to available water supply and demand in Beijing plain, several groundwater regulation scenarios were designed. These different regulation scenarios were simulated with the groundwater model, and assessed using a multi-criteria fuzzy pattern recognition model. This approach is proven to be very useful for scientific analysis of sustainable development and utilization of groundwater resources. The evaluation results show that sustainable development of groundwater resources may be achieved in Beijing plain when various measures such as control of groundwater abstraction and increase of artificial recharge combine favourably.

  15. A numerical model to evaluate potential impacts of sea-level rise on groundwater resources in the Delaware coastal plain

    Science.gov (United States)

    He, C.; McKenna, T. E.; Wang, L.

    2013-12-01

    Sea level rise on the U.S. East Coast has accelerated much faster than in other parts of the world. In Delaware, the estimated sea level could rise as high as 1.5 meters by the year 2100 based on the information in IPCC (2007) and CCSP (2009). In this study, we used a 3-D variable-density groundwater flow model to study the movement of the fresh-water/salt-water interface and water table changes due to sea-level rise. Rather than developing a site-specific model, we analyzed the geospatial features of a serious of sub-watersheds along the coastline of the Delaware Estuary in Delaware using ArcGIS and constructed a representative model to capture the generalized flow patterns and saltwater intrusion rates that occur in typical area. Different scenarios with varying parameters were simulated. The simulation results were then applied to the Delaware River region to evaluate potential impacts of groundwater level changes on the potential land lose.

  16. Simulation of groundwater and nuclide transport in the near-field of the high-level radioactive waste repository with TOUGHREACT

    Institute of Scientific and Technical Information of China (English)

    LI Xun; YANG Zeping; ZHENG Zhihong; WU Hongmei

    2008-01-01

    In order to know the mechanism of groundwater transport and the variation of ion concentrations in the near-field of the high-level radioactive waste repository, the whole process was simulated by EOS3 module of TOUGHREACT. Generally, the pH and cation concentrations vary obviously in the near-field saturated zone due to interaction between groundwater and bentonite. Moreover, the simulated results showed that calcite precipitation could not cause obvious variations in the porosity of media in the near-filed if the chemical components and their concentrations of groundwater and bentonite pore water are similar to those used in this study.

  17. Toxic Levels of Some Heavy Metals in Drinking Groundwater in Dakahlyia Governorate, Egypt in the Year 2010

    Directory of Open Access Journals (Sweden)

    RA Mandour

    2011-03-01

    Full Text Available Fifty-four drinking groundwater samples were collected in April 2010 from some districts of the Dakahlyia governorate, Egypt. The water samples were analyzed by atomic absorption spectrophotometer for iron, manganese, lead, nickel, chromium, zinc, copper, cobalt and cadmium concentrations. All samples but two were found suitable for drinking; from the water sample from Aga district showed slightly higher levels of cadmium and nickel (Ikhtab and Feshbena than other areas; the concentrations were higher than the permissible limits of Egyptian Ministry of Health and World Health Organization.

  18. Increased concentrations of potassium in heartwood of trees in response to groundwater contamination

    Science.gov (United States)

    Vroblesky, D.A.; Yanosky, T.M.; Siegel, F.R.

    1992-01-01

    The wood of tuliptrees (Liriodendron tulipifera L.) growing above groundwater contamination from a hazardous-waste landfill in Maryland contained elevated concentrations of potassium (K). The groundwater contamination also contained elevated concentrations of dissolved K, as well as arsenic (As), cadmium (Cd), chloride (Cl), iron (Fe), manganese (Mn), zinc (Zn), and organic solvents. The dissolved K is derived from disposed smoke munitions. The excess K in the tuliptrees is concentrated in the heartwood, the part of the xylem most depleted in K in trees growing outside of the contamination. These data show that the uptake and translocation of K by tuliptrees can be strongly influenced by the availability of K in groundwater contamination and suggest the utility of this species as an areal indicator of groundwater contamination. ?? 1992 Springer-Verlag New York Inc.

  19. Groundwater level monitoring sampling and analysis plan for the environmental monitoring plan at waste area grouping 6, Oak Ridge National Laboratory, Oak Ridge, Tennessee

    Energy Technology Data Exchange (ETDEWEB)

    NONE

    1995-09-01

    This document is the Groundwater Level Monitoring Sampling and Analysis Plan (SAP) for Waste Area Grouping (WAG) 6 at Oak Ridge National Laboratory (ORNL). Note that this document is referred to as a SAP even though no sampling and analysis will be conducted. The term SAP is used for consistency. The procedures described herein are part of the Environmental Monitoring Plan (EMP) for WAG 6, which also includes monitoring tasks for seeps and springs, groundwater quality, surface water, and meteorological parameters. Separate SAPs are being issued concurrently to describe each of these monitoring programs. This SAP has been written for the use of the field personnel responsible for implementation of the EMP, with the intent that the field personnel will be able to take these documents to the field and quickly find the appropriate steps required to complete a specific task. In many cases, Field Operations Procedures (FOPs) will define the steps required for an activity. The FOPs for the EMP are referenced and briefly described in the relevant sections of the SAPs, and are contained within the FOP Manual. Both these documents (the SAP and the FOP Manual) will be available to personnel in the field.

  20. Groundwater Flow Systems and Their Response to Climate Change: A Need for a Water-System View Approach

    Directory of Open Access Journals (Sweden)

    Joel J. Carrillo-Rivera

    2012-01-01

    Full Text Available Problem statement: The interest in early hydrogeological studies was the aquifer unit, as it is the physical media that stores and permits groundwater transfers from the recharge zone to the discharge zone, making groundwater available to boreholes for water extraction. Approach: Recently, the aquifer concept has been complemented by the groundwater flow system theory, where groundwater may be defined by local, intermediate and regional flow systems. This implies that groundwater may travel from one aquifer unit to another aquifer unit (or more located above or below the former. Water in a local flow system takes months or several years to travel from the recharge to the discharge zone. These flows usually transfer the best natural quality water, so a reduction in precipitation would lessen recharge and diminish stored water, making them more vulnerable to contamination and variability in climatic conditions. Thus, there is a need to define local flows and to enhance actions to protect them from contamination and inefficient extraction. Results: In contrast to local flows, intermediate and regional flows travel from a region, or country, into another, with their recharge processes usually taking place in a zone located far away from the discharge zone (natural or by boreholes. There is a need of groundwater flow systems evaluation by means of an integrated wide system-view analysis of partial evidence represented by surface (soil and vegetation covers as well as hydraulic, isotopic and chemical groundwater characterization in the related geological media where the depth of actual basement rock is paramount as well as discharge areas. The flow system definition may assist in extraction management strategies to control related issues as subsidence, obtained the water quality change, desiccation of springs and water bodies, soil erosion, flooding response, contamination processes in recharge areas, among others; many of which could be efficiently

  1. California Groundwater Management During Drought: Existing and Future Regulatory Approaches

    Science.gov (United States)

    Ekdahl, E.; Boland-Brien, S.; Vanderburgh, B.; Landau, K.; Bean, J.; Peltier, T.

    2015-12-01

    Groundwater has served as an effective buffer to California's crippling drought of 2012-2015, allowing continued agricultural production in many areas where surface water deliveries have been curtailed. However, over-reliance on groundwater has caused plummeting groundwater levels in much of the state's heavily agricultural regions, with annual groundwater overdraft state-wide estimated in the millions of acre-feet per year. Prior to 2015, California water law did not allow for the effective monitoring or assessment of groundwater use; passage of new state regulations will require development of locally-managed plans that, for the first time, require comprehensive groundwater management and groundwater basin sustainability. Because these plans are not required to be implemented for another 25 years, groundwater levels will likely continue to decrease. Some communities that are 100-percent reliant on groundwater as a source of municipal supply may face shortages and supply issues, which may exacerbate known water quality concerns. Examination of community water systems that are reliant on groundwater, their existing water quality issues, and their response to the current drought (through existing mandatory conservation requirements imposed by California state regulators) can identify areas that are particularly susceptible to continued groundwater overdraft.

  2. Changes between early development (1930–60) and recent (2005–15) groundwater-level altitudes and dissolved-solids and nitrate concentrations In and near Gaines, Terry, and Yoakum Counties, Texas

    Science.gov (United States)

    Thomas, Jonathan V.; Teeple, Andrew; Payne, Jason; Ikard, Scott

    2016-06-21

    Llano Estacado Underground Water Conservation District, Sandy Land Underground Water Conservation District, and South Plains Underground Water Conservation District manage groundwater resources in a part of west Texas near the Texas-New Mexico State line. Declining groundwater levels have raised concerns about the amount of available groundwater in the study area and the potential for water-quality changes resulting from dewatering and increased vertical groundwater movement between adjacent water-bearing units.

  3. Experimental evidence for seismically initiated gas bubble nucleation and growth in groundwater as a mechanism for coseismic borehole water level rise and remotely triggered seismicity

    Science.gov (United States)

    Crews, Jackson B.; Cooper, Clay A.

    2014-09-01

    Changes in borehole water levels and remotely triggered seismicity occur in response to near and distant earthquakes at locations around the globe, but the mechanisms for these phenomena are not well understood. Experiments were conducted to show that seismically initiated gas bubble growth in groundwater can trigger a sustained increase in pore fluid pressure consistent in magnitude with observed coseismic borehole water level rise, constituting a physically plausible mechanism for remote triggering of secondary earthquakes through the reduction of effective stress in critically loaded geologic faults. A portion of the CO2 degassing from the Earth's crust dissolves in groundwater where seismic Rayleigh and P waves cause dilational strain, which can reduce pore fluid pressure to or below the bubble pressure, triggering CO2 gas bubble growth in the saturated zone, indicated by a spontaneous buildup of pore fluid pressure. Excess pore fluid pressure was measured in response to the application of 0.1-1.0 MPa, 0.01-0.30 Hz confining stress oscillations to a Berea sandstone core flooded with initially subsaturated aqueous CO2, under conditions representative of a confined aquifer. Confining stress oscillations equivalent to the dynamic stress of the 28 June 1992 Mw 7.3 Landers, California, earthquake Rayleigh wave as it traveled through the Long Valley caldera, and Parkfield, California, increased the pore fluid pressure in the Berea core by an average of 36 ± 15 cm and 23 ± 15 cm of equivalent freshwater head, respectively, in agreement with 41.8 cm and 34 cm rises recorded in wells at those locations.

  4. Status of groundwater levels and storage volume in the Equus Beds aquifer near Wichita, Kansas, January 2006 to January 2010

    Science.gov (United States)

    Hansen, Cristi V.; Aucott, Walter R.

    2010-01-01

    A part of the Equus Beds aquifer in southwestern Harvey County and northwestern Sedgwick County was developed to supply water to residents of Wichita and for irrigation in south-central Kansas. Groundwater pumping for city and agricultural use caused water levels to decline in a large part of the aquifer northwest of Wichita. In 1965, the city of Wichita began using water from Cheney Reservoir in addition to water from the Equus Beds aquifer to meet the city's increasing demand for water. Irrigation pumpage in the area increased substantially during the 1970s and 1980s and contributed to the water-level declines. Water-level declines reached their maximum to date in October 1992.

  5. Status of groundwater levels and storage volume in the Equus Beds aquifer near Wichita, Kansas, January 2016

    Science.gov (United States)

    Klager, Brian J.

    2016-12-29

    The Equus Beds aquifer in south-central Kansas, which is part of the High Plains aquifer, serves as a source of water for municipal and agricultural users in the area. The city of Wichita has used the Equus Beds aquifer as one of its primary water sources since the 1940s. The aquifer in and around Wichita’s well field reached historically low water levels in 1993, prompting the city to adopt new water-use and conservation strategies to ensure future water supply needs were met. Part of the plan was to initiate a managed aquifer recharge program called the Equus Beds Aquifer Storage and Recovery project. The goal of the managed aquifer recharge program is to artificially recharge the Equus Beds aquifer with treated water from the Little Arkansas River. As part of the Equus Beds Aquifer Storage and Recovery project, the city of Wichita and the U.S. Geological Survey have partnered in a long-term cooperative study to monitor and describe the quantity and quality of the water in the Equus Beds aquifer and the Little Arkansas River.The city of Wichita, the Equus Beds Groundwater Management District No. 2, the Kansas Department of Agriculture–Division of Water Resources, and the U.S. Geological Survey collected groundwater levels in numerous wells screened in the Equus Beds aquifer in the area in and around Wichita’s well field in January 2016. The measurements were used to interpolate potentiometric surfaces for shallow and deep parts of the aquifer in the study area. These potentiometric surfaces were compared with potentiometric surfaces from previous years to estimate changes in water levels and storage volume in the study area.Groundwater levels were generally higher in January 2016 than they were in January 2015. On average, in January 2016, groundwater levels in the shallow part of the aquifer were about 3.4 feet higher and groundwater levels in the deep part of the aquifer were about 3.8 feet higher than in January 2015. The volume of water stored in the

  6. Simulation of groundwater level variations using wavelet combined with neural network, linear regression and support vector machine

    Science.gov (United States)

    Ebrahimi, Hadi; Rajaee, Taher

    2017-01-01

    Simulation of groundwater level (GWL) fluctuations is an important task in management of groundwater resources. In this study, the effect of wavelet analysis on the training of the artificial neural network (ANN), multi linear regression (MLR) and support vector regression (SVR) approaches was investigated, and the ANN, MLR and SVR along with the wavelet-ANN (WNN), wavelet-MLR (WLR) and wavelet-SVR (WSVR) models were compared in simulating one-month-ahead of GWL. The only variable used to develop the models was the monthly GWL data recorded over a period of 11 years from two wells in the Qom plain, Iran. The results showed that decomposing GWL time series into several sub-time series, extremely improved the training of the models. For both wells 1 and 2, the Meyer and Db5 wavelets produced better results compared to the other wavelets; which indicated wavelet types had similar behavior in similar case studies. The optimal number of delays was 6 months, which seems to be due to natural phenomena. The best WNN model, using Meyer mother wavelet with two decomposition levels, simulated one-month-ahead with RMSE values being equal to 0.069 m and 0.154 m for wells 1 and 2, respectively. The RMSE values for the WLR model were 0.058 m and 0.111 m, and for WSVR model were 0.136 m and 0.060 m for wells 1 and 2, respectively.

  7. Effect of sea-level rise and climate change on groundwater salinity and agro-hydrology in a low coastal region of the Netherlands

    NARCIS (Netherlands)

    Stuyt, L.C.P.M.; Kabat, P.; Postma, J.; Pomper, A.B.

    1995-01-01

    Scenario studies were carried out to predict the effects of doubled carbon dioxide levels, a 1 °C temperature increase and a 1.2 m sea level rise on seepage, groundwater and crop production. Climatic change was simulated, showing increased precipitation. Simulation of effects of sea level rise on

  8. Water-level changes and directions of ground-water flow in the shallow aquifer, Fallon area, Churchill County, Nevada

    Science.gov (United States)

    Seiler, R.L.; Allander, K.K.

    1993-01-01

    The Truckee-Carson-Pyramid Lake Water Rights Settlement Act of 1990 directed the U.S. Fish and Wildlife Service to acquire water rights for wetland areas in the Carson Desert, Nevada. The public is concerned that htis acquisition of water rights and delivery of the water directly to wildlife areas would result in less recharge to the shallow ground water in the Fallon area and cause domestic wells to go dry. In January 1992, the U.S. Geological Survey, in cooperation with U.S. Fish and Wildlife Service, began a study of the shallow ground-water system in the Fallon area in Churchill County, Nevada. A network of 126 wells in the study area was monitored. Between January and November 1992, water levels in most wells declined, usually less than 2 feet. The maximum measured decline over this period was 2.68 feet in a well near Stillwater Marsh. Between April and July, however, water levels rose in irrigated areas, typically 1 to 2 feet. Newlands Project water deliveries to the study area began soon after the turn of the century. Since then, water levels have risen more than 15 feet across much of the study area. Water lost from unlined irrigtiaon canals caused the stage in Big Soda Lake to rise nearly 60 feet; ground-water levels near the lake have risen 30 to 40 feet. The depth to water in most irrigated areas is now less than 10 feet. The altitude of the water table ranges from 4.025 feet above sea level 11 miles west of Fallon to 3,865 feet in the Stillwater Marsh area. Ground water flows eastward and divides; some flow goes to the northeast toward the Carson Sink and Stillwater areas, and some goes southeastward to Carson Lake.

  9. Development og groundwater flow modeling techniques for the low-level radwaste disposal (III)

    Energy Technology Data Exchange (ETDEWEB)

    Bae, Dae-Seok; Kim, Chun-Soo; Kim, Kyung-Soo; Park, Byung-Yoon; Koh, Yong-Kweon; Park, Hyun-Soo [Korea Atomic Energy Research Institute, Taejeon (Korea)

    2000-12-01

    The project amis to establish the methodology of hydrogeologic assessment by the field application of the evaluation techniques gained and accumulated from the previous hydrogeological research works in Korea. The results of the project and their possible areas for application are (1) acquisition of detailed hydrogeologic information by using a borehole televiewer and a multipacker system, (2) establishing an integrated hydrogeological assessment method for fractured rocks, (3) acquisition of the fracture parameters for fracture modeling, (4) an inversion analysis of hydraulic parameters from fracture network modeling, (5) geostatistical methods for the spatial assignment of hydraulic parameters for fractured rocks, and (6) establishing the groundwater flow modeling procedure for a repository. 75 refs., 72 figs., 34 tabs. (Author)

  10. Comparison of Groundwater Level Models Based on Artificial Neural Networks and ANFIS

    Directory of Open Access Journals (Sweden)

    Nevenka Djurovic

    2015-01-01

    Full Text Available Water table forecasting plays an important role in the management of groundwater resources in agricultural regions where there are drainage systems in river valleys. The results presented in this paper pertain to an area along the left bank of the Danube River, in the Province of Vojvodina, which is the northern part of Serbia. Two soft computing techniques were used in this research: an adaptive neurofuzzy inference system (ANFIS and an artificial neural network (ANN model for one-month water table forecasts at several wells located at different distances from the river. The results suggest that both these techniques represent useful tools for modeling hydrological processes in agriculture, with similar computing and memory capabilities, such that they constitute an exceptionally good numerical framework for generating high-quality models.

  11. Comparison of Groundwater Level Models Based on Artificial Neural Networks and ANFIS

    Science.gov (United States)

    Domazet, Milka; Stricevic, Ruzica; Pocuca, Vesna; Spalevic, Velibor; Pivic, Radmila; Gregoric, Enika; Domazet, Uros

    2015-01-01

    Water table forecasting plays an important role in the management of groundwater resources in agricultural regions where there are drainage systems in river valleys. The results presented in this paper pertain to an area along the left bank of the Danube River, in the Province of Vojvodina, which is the northern part of Serbia. Two soft computing techniques were used in this research: an adaptive neurofuzzy inference system (ANFIS) and an artificial neural network (ANN) model for one-month water table forecasts at several wells located at different distances from the river. The results suggest that both these techniques represent useful tools for modeling hydrological processes in agriculture, with similar computing and memory capabilities, such that they constitute an exceptionally good numerical framework for generating high-quality models. PMID:26759830

  12. Bored boys, graffiti, and YouTube - tracing recent groundwater level changes in a Saudi Arabian cave

    Science.gov (United States)

    Michelsen, Nils; Dirks, Heiko; Schulz, Stephan; Kempe, Stephan; Schüth, Christoph

    2015-04-01

    The Dahl Hith cave is located approximately 30 km southeast of Riyadh, the capital of Saudi Arabia. In the past decades, the groundwater table exposed inside the cave became subject to appreciable changes. After a decline due to agricultural water abstraction for irrigation purposes, the water table exhibited a rapid rise in the last few years. Considering that most of the aquifers of the country show a depletion of the largely fossil groundwater, the mentioned rise is quite unusual. The area does not host an observation well, i.e., reliable data on the piezometric changes is hitherto not available. Hence, two uncommon data sources were used to reconstruct the water level changes: (1) YouTube videos and (2) graffiti inscriptions. (1) The cave is frequently visited by locals and expats from Riyadh and many visitors are willing to share their cave adventures on YouTube. Identifying certain reference points in the uploaded videos (e.g. specific boulders, cave graffiti) and estimating their position relative to the water table allows for an approximate reconstruction of the recent groundwater rise. Information on the observation time is derived from the uploading date. Occasionally, also the exact date of the visit is provided as part of the footage description. (2) Some people documented their visit by graffiti inscriptions. These do not only serve as a marker in the videos, but also contain genuine data on historic water levels: if written on parts of the cave wall, which are only accessible from the water, they indicate the water level at the time of their creation. Fortunately, some graffiti also feature the date of the visit. In order to improve the reliability of the water level estimations, measurements conducted in the course of own site visits in the past few years were considered for the evaluation. Also photographs taken during these surveys helped to improve the quality of the water level reconstruction. The described "Youtube Approach" could be interpreted

  13. Long-Term Response of Groundwater Nitrate Concentrations to Management Regulations in Nebraska's Central Platte Valley

    Directory of Open Access Journals (Sweden)

    Mary E. Exner

    2010-01-01

    Full Text Available The impact of 16 years (1988–2003 of management practices on high groundwater nitrate concentrations in Nebraska's central Platte River valley was assessed in a 58,812-ha (145,215-ac groundwater quality management area intensively cropped to irrigated corn (Zea mays L.. Crop production and groundwater nitrate data were obtained from ~23,800 producer reports. The terrace, comprising ~56% of the study area, is much more intensively cropped to irrigated corn than the bottomland. From 1987 to 2003, average groundwater nitrate concentrations in the primary aquifer beneath the bottomland remained static at ~8 mg N/l. During the same period, average groundwater nitrate concentrations in the primary aquifer beneath the terrace decreased from 26.4 to 22.0 mg N/l at a slow, but significant (p < 0.0001, rate of 0.26 mg N/l/year. Approximately 20% of the decrease in nitrate concentrations can be attributed to increases in the amount of N removed from fields as a consequence of small annual increases in yield. During the study, producers converted ~15% of the ~28,300 furrow-irrigated terrace hectares (~69,800 ac to sprinkler irrigation. The conversion is associated with about an additional 50% of the decline in the nitrate concentration, and demonstrates the importance of both improved water and N management. Average N fertilizer application rates on the terrace were essentially unchanged during the study. The data indicate that groundwater nitrate concentrations have responded to improved management practices instituted by the Central Platte Natural Resources District.

  14. Accounting for groundwater in stream fish thermal habitat responses to climate change.

    Science.gov (United States)

    Snyder, Craig D; Hitt, Nathaniel P; Young, John A

    2015-07-01

    Forecasting climate change effects on aquatic fauna and their habitat requires an understanding of how water temperature responds to changing air temperature (i.e., thermal sensitivity). Previous efforts to forecast climate effects on brook trout (Salvelinus fontinalis) habitat have generally assumed uniform air-water temperature relationships over large areas that cannot account for groundwater inputs and other processes that operate at finer spatial scales. We developed regression models that accounted for groundwater influences on thermal sensitivity from measured air-water temperature relationships within forested watersheds in eastern North America (Shenandoah National Park, Virginia, USA, 78 sites in nine watersheds). We used these reach-scale models to forecast climate change effects on stream temperature and brook trout thermal habitat, and compared our results to previous forecasts based upon large-scale models. Observed stream temperatures were generally less sensitive to air temperature than previously assumed, and we attribute this to the moderating effect of shallow groundwater inputs. Predicted groundwater temperatures from air-water regression models corresponded well to observed groundwater temperatures elsewhere in the study area. Predictions of brook trout future habitat loss derived from our fine-grained models. were far less pessimistic than those from prior models developed at coarser spatial resolutions. However, our models also revealed spatial variation in thermal sensitivity within and among catchments resulting in a patchy distribution of thermally suitable habitat. Habitat fragmentation due to thermal barriers therefore may have an increasingly important role for trout population viability in headwater streams. Our results demonstrate that simple adjustments to air-water temperature regression models can provide a powerful and cost-effective approach for predicting future stream temperatures while accounting for effects of groundwater.

  15. Guidelines for selecting codes for ground-water transport modeling of low-level waste burial sites. Executive summary

    Energy Technology Data Exchange (ETDEWEB)

    Simmons, C.S.; Cole, C.R.

    1985-05-01

    This document was written to provide guidance to managers and site operators on how ground-water transport codes should be selected for assessing burial site performance. There is a need for a formal approach to selecting appropriate codes from the multitude of potentially useful ground-water transport codes that are currently available. Code selection is a problem that requires more than merely considering mathematical equation-solving methods. These guidelines are very general and flexible and are also meant for developing systems simulation models to be used to assess the environmental safety of low-level waste burial facilities. Code selection is only a single aspect of the overall objective of developing a systems simulation model for a burial site. The guidance given here is mainly directed toward applications-oriented users, but managers and site operators need to be familiar with this information to direct the development of scientifically credible and defensible transport assessment models. Some specific advice for managers and site operators on how to direct a modeling exercise is based on the following five steps: identify specific questions and study objectives; establish costs and schedules for achieving answers; enlist the aid of professional model applications group; decide on approach with applications group and guide code selection; and facilitate the availability of site-specific data. These five steps for managers/site operators are discussed in detail following an explanation of the nine systems model development steps, which are presented first to clarify what code selection entails.

  16. Potential effects of groundwater pumping on water levels, phreatophytes, and spring discharges in Spring and Snake Valleys, White Pine County, Nevada, and adjacent areas in Nevada and Utah

    Science.gov (United States)

    Halford, Keith J.; Plume, Russell W.

    2011-01-01

    Assessing hydrologic effects of developing groundwater supplies in Snake Valley required numerical, groundwater-flow models to estimate the timing and magnitude of capture from streams, springs, wetlands, and phreatophytes. Estimating general water-table decline also required groundwater simulation. The hydraulic conductivity of basin fill and transmissivity of basement-rock distributions in Spring and Snake Valleys were refined by calibrating a steady state, three-dimensional, MODFLOW model of the carbonate-rock province to predevelopment conditions. Hydraulic properties and boundary conditions were defined primarily from the Regional Aquifer-System Analysis (RASA) model except in Spring and Snake Valleys. This locally refined model was referred to as the Great Basin National Park calibration (GBNP-C) model. Groundwater discharges from phreatophyte areas and springs in Spring and Snake Valleys were simulated as specified discharges in the GBNP-C model. These discharges equaled mapped rates and measured discharges, respectively. Recharge, hydraulic conductivity, and transmissivity were distributed throughout Spring and Snake Valleys with pilot points and interpolated to model cells with kriging in geologically similar areas. Transmissivity of the basement rocks was estimated because thickness is correlated poorly with transmissivity. Transmissivity estimates were constrained by aquifer-test results in basin-fill and carbonate-rock aquifers. Recharge, hydraulic conductivity, and transmissivity distributions of the GBNP-C model were estimated by minimizing a weighted composite, sum-of-squares objective function that included measurement and Tikhonov regularization observations. Tikhonov regularization observations were equations that defined preferred relations between the pilot points. Measured water levels, water levels that were simulated with RASA, depth-to-water beneath distributed groundwater and spring discharges, land-surface altitudes, spring discharge at

  17. Variability of surface-water quantity and quality and shallow groundwater levels and quality within the Rio Grande Project Area, New Mexico and Texas, 2009–13

    Science.gov (United States)

    Driscoll, Jessica M.; Sherson, Lauren R.

    2016-03-15

    . Calculation of the change of salt loads using a mass-balance approach was applied between streamgages. Results from these calculations suggest differing responses to releases in the Rincon and Mesilla Valleys over the period of study; there is a decreasing sink of salt in the Rincon Valley whereas there is an increasing sink of salt in the Mesilla Valley. Daily groundwater-level and water-quality data from shallow wells within the two alluvial valleys show spatial heterogeneity of water quality over the study period. Mass-balance salt-loading trends during the study period are similar to previous trends during the 1950s drought as well as a wet period in the 1980s. The similarity of salt-loading trends from the 1950s, 1980s, and 2000s independent of the climate indicates salt loading in this hydrologic setting may be driven by water-use practices rather than a single climatic variable.

  18. Groundwater response to changing water-use practices in sloping aquifers

    Science.gov (United States)

    Groundwater flow is examined for recharge and extraction within a sloping aquifer. Fundamental equations are commonly formulated either in s-n coordinates where s is tangent to the base or in x-z coordinates where x is horizontal. Consistency between these two formulations is achieved here by incorp...

  19. Land subsidence induced by groundwater extraction and building damage level assessment-a case study of Datun,China

    Institute of Scientific and Technical Information of China (English)

    FENG Qi-yan; LIU Gang-jun; MENG Lei; FU Er-jiang; ZHANG Hai-rong; ZHANG Ke-fei

    2008-01-01

    As in many parts of the world, long-term excessive extraction of groundwater has caused significant land-surface subsidence in the residential areas of Datun coal mining district in East China. The recorded maximum level of subsidence in the area since 1976 to 2006 is 863 mm, and the area with an accumulative subsidence more than 200 mm has reached 33.1 km2 by the end of 2006. Over ten cases of building crack due to ground subsidence have already been observed. Spatial variation in ground subsidence often leads to a corresponding pattern of ground deformation. Buildings and underground infrastructures have been under a higher risk of damage in locations with greater differential ground deformation. Governmental guideline in China classifies building damages into four different levels, based on the observable measures such as the width of wall crack, the degree of door and window deformation, the degree of wall inclination and the degree of structural destruction. Building damage level (BDL) is estimated by means of ground deformation analysis in terms of variations in slope gradient and curvature. Ground deformation analysis in terms of variations in slope gradient has shown that the areas of BDL Ⅲ and BDL Ⅱ sites account for about 0.013 km2 and 0.284km2 respectively in 2006, and the predicted areas of BDL (define this first) Ⅲ and Ⅱ sites will be about 0.029 km2 and 0.423 km2respectively by 2010. The situation is getting worse as subsidence continues. That calls for effective strategies for subsidence mitigation and damage reduction, in terms of sustainable groundwater extraction, enhanced monitoring and the establishment of early warning systems.

  20. Evaluation of Elevated Tritium Levels in Groundwater Downgradient from the 618-11 Burial Ground Phase I Investigations

    Energy Technology Data Exchange (ETDEWEB)

    Dresel, P.E.; Smith, R.M.; Williams, B.A.; Thompson, C.J.; Evans, J.C.; Hulstrom, L.C.

    2000-05-01

    This report describes the results of the preliminary investigation of elevated tritium in groundwater discovered near the 618-11 burial ground, located in the eastern part of the Hanford Site. Tritium in one well downgradient of the burial ground was detected at levels up to 8,140,000 pCi/L. The 618-11 burial ground received a variety of radioactive waste from the 300 Area between 1962 and 1967. The burial ground covers 3.5 hectare (8.6 acre) and contains trenches, large diameter caissons, and vertical pipe storage units. The burial ground was stabilized with a native sediment covering. The Energy Northwest reactor complex was constructed immediately east of the burial ground.

  1. Database of groundwater levels and hydrograph descriptions for the Nevada Test Site area, Nye County, Nevada

    Science.gov (United States)

    Elliott, Peggy E.; Fenelon, Joseph M.

    2010-01-01

    A database containing water levels measured from wells in and near areas of underground nuclear testing at the Nevada Test Site was developed. The water-level measurements were collected from 1941 to 2016. The database provides information for each well including well construction, borehole lithology, units contributing water to the well, and general site remarks. Water-level information provided in the database includes measurement source, status, method, accuracy, and specific water-level remarks. Additionally, the database provides hydrograph narratives that document the water-level history and describe and interpret the water-level hydrograph for each well.Water levels in the database were quality assured and analyzed. Multiple conditions were assigned to each water-level measurement to describe the hydrologic conditions at the time of measurement. General quality, temporal variability, regional significance, and hydrologic conditions are attributed to each water-level measurement.

  2. Hydrologic conditions in urban Miami-Dade County, Florida, and the effect of groundwater pumpage and increased sea level on canal leakage and regional groundwater flow

    Science.gov (United States)

    Hughes, Joseph D.; White, Jeremy T.

    2014-01-01

    The extensive and highly managed surface-water system in southeastern Florida constructed during the 20th Century has allowed for the westward expansion of urban and agricultural activities in Miami-Dade County. In urban areas of the county, the surface-water system is used to (1) control urban flooding, (2) supply recharge to production well fields, and (3) control seawater intrusion. Previous studies in Miami-Dade County have determined that on a local scale, leakage from canals adjacent to well fields can supply a large percentage (46 to 78 percent) of the total groundwater pumpage from production well fields. Canals in the urban areas also receive seepage from the Biscayne aquifer that is derived from a combination of local rainfall and groundwater flow from Water Conservation Area 3 and Everglades National Park, which are west of urban areas of Miami-Dade County.

  3. Water level observations from Unmanned Aerial Vehicles (UAVs) for improving probabilistic estimations of interaction between rivers and groundwater

    Science.gov (United States)

    Bandini, Filippo; Butts, Michael; Vammen Jacobsen, Torsten; Bauer-Gottwein, Peter

    2016-04-01

    Integrated hydrological models are generally calibrated against observations of river discharge and piezometric head in groundwater aquifers. Integrated hydrological models are rarely calibrated against spatially distributed water level observations measured by either in-situ stations or spaceborne platforms. Indeed in-situ observations derived from ground-based stations are generally spaced too far apart to capture spatial patterns in the water surface. On the other hand spaceborne observations have limited spatial resolution. Additionally satellite observations have a temporal resolution which is not ideal for observing the temporal patterns of the hydrological variables during extreme events. UAVs (Unmanned Aerial Vehicles) offer several advantages: i) high spatial resolution; ii) tracking of the water body better than any satellite technology; iii) timing of the sampling merely depending on the operators. In this case study the Mølleåen river (Denmark) and its catchment have been simulated through an integrated hydrological model (MIKE 11-MIKE SHE). This model was initially calibrated against observations of river discharge retrieved by in-situ stations and against piezometric head of the aquifers. Subsequently the hydrological model has been calibrated against dense spatially distributed water level observations, which could potentially be retrieved by UAVs. Error characteristics of synthetic UAV water level observations were taken from a recent proof-of-concept study. Since the technology for ranging water level is under development, UAV synthetic water level observations were extracted from another model of the river with higher spatial resolution (cross sections located every 10 m). This model with high resolution is assumed to be absolute truth for the purpose of this work. The river model with the coarser resolution has been calibrated against the synthetic water level observations through Differential Evolution Adaptive Metropolis (DREAM) algorithm, an

  4. Groundwater Diffuse Recharge and its Response to Climate Changes in Semi-Arid Northwestern China

    Directory of Open Access Journals (Sweden)

    Lin Deng

    2015-01-01

    Full Text Available Understanding the processes and rates of groundwater recharge in arid and semi-arid areas is crucial for utilizing and managing groundwater resources sustainably. We obtained three chloride profiles of the unsaturated-zone in the desert/loess transition zone of northwestern China and reconstructed the groundwater recharge variations over the last 11, 21, and 37 years, respectively, using the generalized chloride mass balance (GCMB method. The average recharge rates were 43.7, 43.5, and 45.1 mm yr-1, respectively, which are similar to those evaluated by the chloride mass balance (CMB or GCMB methods in other semi-arid regions. The results indicate that the annual recharge rates were not in complete linear proportion to the corresponding annual precipitations, although both exhibited descending tendencies on the whole. Comparisons between the daily precipitation aggregate at different intensity and recharge rates reveal that the occurrence of relatively heavy daily precipitation per year may contribute to such nonlinearity between annual precipitation and recharge. The possible influences of vegetation cover alterations following precipitation change cannot be excluded as well. The approximately negative correlation between the average annual recharge and temperature suggests that changes in temperature have had significant influences on recharge.

  5. Zr and U determination at trace level in simulated deep groundwater by Q ICP-MS using extraction chromatography.

    Science.gov (United States)

    Gautier, C; Coppo, M; Caussignac, C; Laszak, I; Fichet, P; Goutelard, F

    2013-03-15

    In the framework of trace element analysis by Q ICP-MS in a simulated deep Callovo-Oxfordian groundwater, separation procedures based on extraction chromatography were developed to eliminate the high salt contents and to concentrate Zr and U simultaneously. Theoretical and experimental speciation studies showed the importance of adjusting the medium to HNO₃/HF (0.5 M/0.005 M) to guarantee the stability over time of the analytes before removal of the matrix. Two preconcentration methods based on TRU and TODGA resins were optimized for the simultaneous isolation of Zr and U prior to Q ICP-MS measurements. Using TRU resin, alkali and alkali earth metals contained in the deep groundwater were removed with 2 M HNO₃ whereas Zr and U were recovered with a HNO₃/NH₄HC₂O₄ (0.02 M/0.05 M) medium. For the separation protocol based on TODGA resin, alkali and alkali earth metals were eliminated with 3 M and 11 M HNO₃ while Zr and U were simultaneously stripped with a HNO₃/HF (0.5 M/0.2 M) medium. The procedure optimized on TODGA resin was validated with the French AFNOR NF T90-210 standard by studying linearity, limits of quantification (LOQ) and separation yields. The LOQ was determined at 0.008 μg L(-1) for Zr and U after the separation. Both analytes were recovered quantitatively. Compared to a sample dilution implemented to reduce the matrix effects, the developed preconcentration method allowed improving the sensitivity up to a 20 fold factor for Zr and U measurements at trace level by Q ICP-MS. Copyright © 2012 Elsevier B.V. All rights reserved.

  6. AUTOMATING GROUNDWATER SAMPLING AT HANFORD

    Energy Technology Data Exchange (ETDEWEB)

    CONNELL CW; HILDEBRAND RD; CONLEY SF; CUNNINGHAM DE

    2009-01-16

    Until this past October, Fluor Hanford managed Hanford's integrated groundwater program for the U.S. Department of Energy (DOE). With the new contract awards at the Site, however, the CH2M HILL Plateau Remediation Company (CHPRC) has assumed responsibility for the groundwater-monitoring programs at the 586-square-mile reservation in southeastern Washington State. These programs are regulated by the Resource Conservation and Recovery Act (RCRA) and the Comprehensive Environmental Response Compensation and Liability Act (CERCLA). The purpose of monitoring is to track existing groundwater contamination from past practices, as well as other potential contamination that might originate from RCRA treatment, storage, and disposal (TSD) facilities. An integral part of the groundwater-monitoring program involves taking samples of the groundwater and measuring the water levels in wells scattered across the site. More than 1,200 wells are sampled each year. Historically, field personnel or 'samplers' have been issued pre-printed forms that have information about the well(s) for a particular sampling evolution. This information is taken from the Hanford Well Information System (HWIS) and the Hanford Environmental Information System (HEIS)--official electronic databases. The samplers used these hardcopy forms to document the groundwater samples and well water-levels. After recording the entries in the field, the samplers turned the forms in at the end of the day and the collected information was posted onto a spreadsheet that was then printed and included in a log book. The log book was then used to make manual entries of the new information into the software application(s) for the HEIS and HWIS databases. This is a pilot project for automating this tedious process by providing an electronic tool for automating water-level measurements and groundwater field-sampling activities. The automation will eliminate the manual forms and associated data entry, improve the

  7. Marine water from mid-Holocene sea level highstand trapped in a coastal aquifer: Evidence from groundwater isotopes, and environmental significance

    Energy Technology Data Exchange (ETDEWEB)

    Lee, Stephen [School of Civil, Environmental and Chemical Engineering, RMIT University, Melbourne (Australia); Currell, Matthew, E-mail: Matthew.currell@rmit.edu.au [School of Civil, Environmental and Chemical Engineering, RMIT University, Melbourne (Australia); Cendón, Dioni I. [Australian Nuclear Science and Technology Organisation, Kirrawee (Australia); Connected Water Initiative, School of Biological, Earth and Environmental Sciences, University of New South Wales (UNSW), Sydney (Australia)

    2016-02-15

    A multi-layered coastal aquifer in southeast Australia was assessed using environmental isotopes, to identify the origins of salinity and its links to palaeo-environmental setting. Spatial distribution of groundwater salinity (electrical conductivity values ranging from 0.395 to 56.1 mS/cm) was examined along the coastline along with geological, isotopic and chemical data. This allowed assessment of different salinity sources and emplacement mechanisms. Molar chloride/bromide ratios range from 619 to 1070 (621 to 705 in samples with EC > 15 mS/cm), indicating salts are predominantly marine. Two distinct vertical salinity profiles were observed, one with increasing salinity with depth and another with saline shallow water overlying fresh groundwater. The saline shallow groundwater (EC = 45.4 to 55.7 mS/cm) has somewhat marine-like stable isotope ratios (δ{sup 18}O = − 2.4 to − 1.9 ‰) and radiocarbon activities indicative of middle Holocene emplacement (47.4 to 60.4 pMC). This overlies fresher groundwater with late Pleistocene radiocarbon ages and meteoric stable isotopes (δ{sup 18}O = − 5.5 to − 4.6‰). The configuration suggests surface inundation of the upper sediments by marine water during the mid-Holocene (c. 2–8 kyr BP), when sea level was 1–2 m above today's level. Profiles of chloride, stable isotopes, and radiocarbon indicate mixing between this pre-modern marine water and fresh meteoric groundwater to varying degrees around the coastline. Mixing calculations using chloride and stable isotopes show that in addition to fresh-marine water mixing, some salinity is derived from transpiration by halophytic vegetation (e.g. mangroves). The δ{sup 13}C ratios in saline water (− 17.6 to − 18.4‰) also have vegetation/organic matter signatures, consistent with emplacement by surface inundation and extensive interaction between vegetation and recharging groundwater. Saline shallow groundwater is preserved only in areas where low

  8. Quantifying the link between crop production and mined groundwater irrigation in China.

    Science.gov (United States)

    Grogan, Danielle S; Zhang, Fan; Prusevich, Alexander; Lammers, Richard B; Wisser, Dominik; Glidden, Stanley; Li, Changsheng; Frolking, Steve

    2015-04-01

    In response to increasing demand for food, Chinese agriculture has both expanded and intensified over the past several decades. Irrigation has played a key role in increasing crop production, and groundwater is now an important source of irrigation water. Groundwater abstraction in excess of recharge (which we use here to estimate groundwater mining) has resulted in declining groundwater levels and could eventually restrict groundwater availability. In this study we used a hydrological model, WBMplus, in conjunction with a process based crop growth model, DNDC, to evaluate Chinese agriculture's recent dependence upon mined groundwater, and to quantify mined groundwater-dependent crop production across a domain that includes variation in climate, crop choice, and management practices. This methodology allowed for the direct attribution of crop production to irrigation water from rivers and reservoirs, shallow (renewable) groundwater, and mined groundwater. Simulating 20 years of weather variability and circa year 2000 crop areas, we found that mined groundwater fulfilled 20%-49% of gross irrigation water demand, assuming all demand was met. Mined groundwater accounted for 15%-27% of national total crop production. There was high spatial variability across China in irrigation water demand and crop production derived from mined groundwater. We find that climate variability and mined groundwater demand do not operate independently; rather, years in which irrigation water demand is high due to the relatively hot and dry climate also experience limited surface water supplies and therefore have less surface water with which to meet that high irrigation water demand.

  9. Groundwater and Terrestrial Water Storage

    Science.gov (United States)

    Rodell, Matthew; Chambers, Don P.; Famiglietti, James S.

    2011-01-01

    Most people think of groundwater as a resource, but it is also a useful indicator of climate variability and human impacts on the environment. Groundwater storage varies slowly relative to other non-frozen components of the water cycle, encapsulating long period variations and trends in surface meteorology. On seasonal to interannual timescales, groundwater is as dynamic as soil moisture, and it has been shown that groundwater storage changes have contributed to sea level variations. Groundwater monitoring well measurements are too sporadic and poorly assembled outside of the United States and a few other nations to permit direct global assessment of groundwater variability. However, observational estimates of terrestrial water storage (TWS) variations from the GRACE satellites largely represent groundwater storage variations on an interannual basis, save for high latitude/altitude (dominated by snow and ice) and wet tropical (surface water) regions. A figure maps changes in mean annual TWS from 2009 to 2010, based on GRACE, reflecting hydroclimatic conditions in 2010. Severe droughts impacted Russia and the Amazon, and drier than normal weather also affected the Indochinese peninsula, parts of central and southern Africa, and western Australia. Groundwater depletion continued in northern India, while heavy rains in California helped to replenish aquifers that have been depleted by drought and withdrawals for irrigation, though they are still below normal levels. Droughts in northern Argentina and western China similarly abated. Wet weather raised aquifer levels broadly across western Europe. Rains in eastern Australia caused flooding to the north and helped to mitigate a decade long drought in the south. Significant reductions in TWS seen in the coast of Alaska and the Patagonian Andes represent ongoing glacier melt, not groundwater depletion. Figures plot time series of zonal mean and global GRACE derived non-seasonal TWS anomalies (deviation from the mean of

  10. Seismically Initiated Carbon Dioxide Gas Bubble Growth in Groundwater: A Mechanism for Co-seismic Borehole Water Level Rise and Remotely Triggered Secondary Seismicity

    Science.gov (United States)

    Crews, Jackson B.

    of freshwater. Co-seismic borehole water level increases of the same magnitude were observed in Parkfield, California, and Long Valley caldera, California, in response to the propagation of a Rayleigh wave in the same amplitude and frequency range produced by the June 28, 1992 MW 7.3 Landers, California, earthquake. Co-seismic borehole water level rise is well documented in the literature, but the mechanism is not well understood, and the results of core-scale experiments indicate that seismically initiated CO2 gas bubble nucleation and growth in groundwater is a reasonable mechanism. Remotely triggered secondary seismicity is also well documented, and the reduction of effective stress due to CO2 bubble nucleation and growth in critically loaded faults may potentially explain how, for example, the June 28, 1992 MW 7.3 Landers, California, earthquake triggered seismicity as far away as Yellowstone, Wyoming, 1250 km from the hypocenter. A numerical simulation was conducted using Euler's method and a first-order kinetic model to compute the pore fluid pressure response to confining stress excursions on a Berea sandstone core flooded with initially under-saturated aqueous CO2. The model was calibrated on the pore pressure response to a rapid drop and later recovery of the confining stress. The model predicted decreasing overpressure as the confining stress oscillation frequency increased from 0.05 Hz to 0.30 Hz, in contradiction with the experimental results and field observations, which exhibit larger excess pore fluid pressure in response to higher frequency oscillations. The limitations of the numerical model point to the important influence of non-ideal behavior arising from a discontinuous gas phase and complex dynamics at the gas-liquid interface.

  11. Elevated levels of iron in groundwater in Prey Veng province in Cambodia: a possible factor contributing to high iron stores in women.

    Science.gov (United States)

    Karakochuk, Crystal D; Murphy, Heather M; Whitfield, Kyly C; Barr, Susan I; Vercauteren, Suzanne M; Talukder, Aminuzzaman; Porter, Keith; Kroeun, Hou; Eath, Many; McLean, Judy; Green, Timothy J

    2015-06-01

    Iron is a natural element found in food, water and soil and is essential for human health. Our aim was to determine the levels of iron and 25 other metals and trace elements in groundwater from 22 households in Prey Veng, Cambodia. Water analyses were conducted using inductively coupled plasma-mass spectrometry and optical emission spectrometry. Compared to the 2011 World Health Organization guidelines for drinking water quality, aluminum, iron and manganese exceeded maximum levels (in 4.5, 72.7 and 40.9% of samples, respectively). Compared to the 2004 Cambodian drinking water quality standards, iron and manganese exceeded maximum levels (in 59.1 and 36.4% of samples, respectively). We found no evidence of arsenic contamination. Guidelines for iron were established primarily for esthetic reasons (e.g. taste), whereas other metals and elements have adverse effects associated with toxicity. Iron in groundwater ranged from 134 to 5,200 μg/L (mean ∼1,422 μg/L). Based on a daily consumption of 3 L groundwater, this equates to ∼0.4-15.6 mg iron (mean ∼4.3 mg/day), which may be contributing to high iron stores and the low prevalence of iron deficiency anemia in Prey Veng women. Elevated levels of manganese in groundwater are a concern and warrant further investigation.

  12. Limits to global groundwater consumption

    Science.gov (United States)

    de Graaf, I.; Van Beek, L. P.; Sutanudjaja, E.; Wada, Y.; Bierkens, M. F.

    2016-12-01

    Groundwater is the largest accessible freshwater resource worldwide and is of critical importance for irrigation, and so for global food security. For many regions of the world where groundwater abstraction exceeds groundwater recharge, persistent groundwater depletion occurs. A direct consequence of depletion is falling groundwater levels, reducing baseflows to rivers, harming ecosystems. Also, pumping costs increase, wells dry up and land subsidence can occur. Water demands are expected to increase further due to growing population, economic development and climate change, posing the urgent question how sustainable current water abstractions are worldwide and where and when these abstractions approach conceivable limits with all the associated problems. Here, we estimated past and future trends (1960-2050) in groundwater levels resulting from changes in abstractions and climate and predicted when limits of groundwater consumption are reached. We explored these limits by predicting where and when groundwater levels drop that low that groundwater becomes unattainable for abstractions and how river flows are affected. Water availabilities, abstractions, and lateral groundwater flows are simulated (5 arcmin. resolution) using a coupled version of the global hydrological model PCR-GLOBWB and a groundwater model based on MODFLOW. The groundwater model includes a parameterization of the worlds confined and unconfined aquifer systems, needed for a realistic simulation of groundwater head dynamics. Results show that, next to the existing regions experiencing groundwater depletion (like India, Pakistan, Central Valley) new regions will develop, e.g. Southern Europe, the Middle East, and Africa. Using a limit that reflects present-day feasibility of groundwater abstraction, we estimate that in 2050 groundwater becomes unattainable for 20% of the global population, mainly in the developing countries and pumping cost will increase significantly. Largest impacts are found

  13. Ground-water discharge determined from measurements of evapotranspiration, other available hydrologic components, and shallow water-level changes, Oasis Valley, Nye County, Nevada

    Science.gov (United States)

    Reiner, S.R.; Laczniak, R.J.; DeMeo, G.A.; Smith, Jody L.; Elliott, P.E.; Nylund, W.E.; Fridrich, C.J.

    2002-01-01

    component of 0.5 foot, is estimated to be about 6,000 acre-feet. Annual subsurface outflow from Oasis Valley into the Amargosa Desert is estimated to be between 30 and 130 acre-feet. Estimates of total annual ground-water withdrawal from Oasis Valley by municipal and non-municipal users in 1996 and 1999 are 440 acre-feet and 210 acre-feet, respectively. Based on these values, natural annual ground-water discharge from Oasis Valley is about 6,100 acre-feet. Total annual discharge was 6,500 acre-ft in 1996 and 6,300 acre-ft in 1999. This quantity of natural ground-water discharge from Oasis Valley exceeds the previous estimate made in 1962 by a factor of about 2.5. Water levels were measured in Oasis Valley to gain additional insight into the ET process. In shallow wells, water levels showed annual fluctuations as large as 7 feet and daily fluctuations as large as 0.2 foot. These fluctuations may be attributed to water loss associated with evapotranspiration. In shallow wells affected by ET, annual minimum depths to water generally occurred in winter or early spring shortly after daily ET reached minimum rates. Annual maximum depths to water generally occurred in late summer or fall shortly after daily ET reached maximum rates. The magnitude of daily water-level fluctuations generally increased as ET increased and decreased as depth to water increased.

  14. Linking Organic Matter Deposition And Iron Mineral Transformations to Groundwater Arsenic Levels in the Mekong Delta, Cambodia

    Energy Technology Data Exchange (ETDEWEB)

    Quicksall, A.N.; Bostick, B.C.; Sampson, M.L.

    2009-05-21

    Enriched As in drinking water wells in south and Southeast Asia has increased the risk of cancer for nearly 100 million people. This enrichment is generally attributed to the reductive dissolution of Fe oxides; however, the complex expression of As enrichment in these areas is not yet well understood. Here, the coupled sedimentological and geochemical factors that contribute to the extent and spatial distribution of groundwater As concentrations in the Mekong River delta, Cambodia in an avulsed scroll bar sequence are examined. X-Ray absorption spectroscopy (XAS) was used to determine Fe and As speciation in redox preserved sediment collected from drilled cores. Dissolved As, Fe and S solution concentrations in existing and newly drilled wells (cores) differed considerably depending on their source sedimentology. The rapid burial of organic matter in the scroll bar sequence facilitated the development of extensive Fe-reducing conditions, and As release into the aquifer. In older features organic C levels are high enough to sustain extensive Fe reduction and provide ample SO{sub 4} which is reduced to sulfide. This S reduction impacts As levels; As is sequestered in sulfide minerals outside of the scrollbar sequence, decreasing pore water concentrations. In contrast, As is depleted in sediments from the scroll sequence, and associated with elevated pore water aqueous concentrations. The concentration and form of organic C in the scrollbar sequence is related to depositional environment, and can facilitate Fe and S mineral transformations, distinct sedimentary environments explain a portion of the inherent heterogeneity of aquifer As concentrations.

  15. Excel Spreadsheet Tools for Analyzing Groundwater Level Records and Displaying Information in ArcMap

    Science.gov (United States)

    Tillman, Fred D

    2009-01-01

    When beginning hydrologic investigations, a first action is often to gather existing sources of well information, compile this information into a single dataset, and visualize this information in a geographic information system (GIS) environment. This report presents tools (macros) developed using Visual Basic for Applications (VBA) for Microsoft Excel 2007 to assist in these tasks. One tool combines multiple datasets into a single worksheet and formats the resulting data for use by the other tools. A second tool produces summary information about the dataset, such as a list of unique site identification numbers, the number of water-level observations for each, and a table of the number of sites with a listed number of water-level observations. A third tool creates subsets of the original dataset based on user-specified options and produces a worksheet with water-level information for each well in the subset, including the average and standard deviation of water-level observations and maximum decline and rise in water levels between any two observations, among other information. This water-level information worksheet can be imported directly into ESRI ArcMap as an 'XY Data' file, and each of the fields of summary well information can be used for custom display. A separate set of VBA tools distributed in an additional Excel workbook creates hydrograph charts of each of the wells in the data subset produced by the aforementioned tools and produces portable document format (PDF) versions of the hydrograph charts. These PDF hydrographs can be hyperlinked to well locations in ArcMap or other GIS applications.

  16. Natural background levels and threshold values of chemical species in three large-scale groundwater bodies in Northern Italy

    Energy Technology Data Exchange (ETDEWEB)

    Molinari, Antonio, E-mail: ant.molinari2002@libero.it [Politecnico di Milano, Dipartimento di Ingegneria Idraulica, Ambientale, Infrastrutture Viarie e Rilevamento, Piazza L. Da Vinci, 32-20133 Milano (Italy); Guadagnini, Laura [Politecnico di Milano, Dipartimento di Ingegneria Idraulica, Ambientale, Infrastrutture Viarie e Rilevamento, Piazza L. Da Vinci, 32-20133 Milano (Italy); Marcaccio, Marco [ARPA Emilia-Romagna, Direzione Tecnica, Largo Caduti del Lavoro, 6-40122 Bologna (Italy); Guadagnini, Alberto [Politecnico di Milano, Dipartimento di Ingegneria Idraulica, Ambientale, Infrastrutture Viarie e Rilevamento, Piazza L. Da Vinci, 32-20133 Milano (Italy)

    2012-05-15

    We analyze natural background levels (NBLs) and threshold values (TVs) of spatially distributed chemical species (NH{sub 4}, B and As) which may be a potential pressure and concern in three large scale alluvial and fluvio-deltaic aquifers at different depths of the Apennines and Po river plains in Emilia-Romagna, Northern Italy. Our results are based on statistical methodologies designed to separate the natural and anthropogenic contributions in monitored concentrations by modeling the empirical distribution of the detected concentration with a mixture of probability density functions. Available chemical observations are taken over a 20 years period and are associated with different depths and cover planar investigation scales of the order of hundreds of kilometers. High concentration values detected for NH{sub 4} and B appear to be related to high natural background levels. Due to interaction with the host rock in different geochemical environments we observed that concentration vary in time and space (including in depth) consistently with the hydrogeochemical features and the occurrence of natural attenuation mechanisms in the analyzed reservoirs. Conversely, estimated As NBLs are not consistent with the conceptual model of the hydrogeochemical behavior of the systems analyzed and experimental evidences of As content in aquifer cores. This is due to the inability of these techniques to incorporate the complex dynamics of the processes associated with the specific hydrogeochemical setting. Statistical analyses performed upon aggregating the concentration data according to different time observation windows allow identifying temporal dynamics of NBLs and TVs of target compounds within the observation time frame. Our results highlight the benefit of a dynamic monitoring process and analysis of well demarcated groundwater bodies to update the associated NBLs as a function of the temporal dependence of natural processes occurring in the subsurface. Monitoring

  17. The effects of artificial recharge on groundwater levels and water quality in the west hydrogeologic unit of the Warren subbasin, San Bernardino County, California

    Science.gov (United States)

    Stamos, Christina L.; Martin, Peter; Everett, Rhett; Izbicki, John A.

    2013-01-01

    Between the late 1940s and 1994, groundwater levels in the Warren subbasin, California, declined by as much as 300 feet because pumping exceeded sparse natural recharge. In response, the local water district, Hi-Desert Water District, implemented an artificial-recharge program in early 1995 using imported water from the California State Water Project. Subsequently, the water table rose by as much as 250 feet; however, a study done by the U.S. Geological Survey found that the rising water table entrained high-nitrate septic effluent, which caused nitrate (as nitrogen) concentrations in some wells to increase to more than the U.S. Environmental Protection Agency maximum contaminant level of 10 milligrams per liter.. A new artificial-recharge site (site 3) was constructed in 2006 and this study, which started in 2004, was done to address concerns about the possible migration of nitrates in the unsaturated zone. The objectives of this study were to: (1) characterize the hydraulic, chemical, and microbiological properties of the unsaturated zone; (2) monitor changes in water levels and water quality in response to the artificial-recharge program at site 3; (3) determine if nitrates from septic effluent infiltrated through the unsaturated zone to the water table; (4) determine the potential for nitrates within the unsaturated zone to mobilize and contaminate the groundwater as the water table rises in response to artificial recharge; and (5) determine the presence and amount of dissolved organic carbon because of its potential to react with disinfection byproducts during the treatment of water for public use. Two monitoring sites were installed and instrumented with heat-dissipation probes, advanced tensiometers, suction-cup lysimeters, and wells so that the arrival and effects of recharging water from the State Water Project through the 250 to 425 foot-thick unsaturated zone and groundwater system could be closely observed. Monitoring site YVUZ-1 was located between two

  18. Water level observations from Unmanned Aerial Vehicles for improving estimates of surface water-groundwater interaction

    DEFF Research Database (Denmark)

    Bandini, Filippo; Butts, Michael; Vammen Jacobsen, Torsten

    2017-01-01

    . However, traditional river gauging stations are normally spaced too far apart to capture spatial patterns in the water surface, while spaceborne observations have limited spatial and temporal resolution. UAVs (Unmanned Aerial Vehicles) can retrieve river water level measurements, providing: i) high...

  19. Microbial community response to addition of polylactate compounds to stimulate hexavalent chromium reduction in groundwater.

    Science.gov (United States)

    Brodie, Eoin L; Joyner, Dominique C; Faybishenko, Boris; Conrad, Mark E; Rios-Velazquez, Carlos; Malave, Josue; Martinez, Ramon; Mork, Benjamin; Willett, Anna; Koenigsberg, Steven; Herman, Donald J; Firestone, Mary K; Hazen, Terry C

    2011-10-01

    To evaluate the efficacy of bioimmobilization of Cr(VI) in groundwater at the Department of Energy Hanford site, we conducted a series of microcosm experiments using a range of commercial electron donors with varying degrees of lactate polymerization (polylactate). These experiments were conducted using Hanford Formation sediments (coarse sand and gravel) immersed in Hanford groundwater, which were amended with Cr(VI) and several types of lactate-based electron donors (Hydrogen Release Compound, HRC; primer-HRC, pHRC; extended release HRC) and the polylactate-cysteine form (Metal Remediation Compound, MRC). The results showed that polylactate compounds stimulated an increase in bacterial biomass and activity to a greater extent than sodium lactate when applied at equivalent carbon concentrations. At the same time, concentrations of headspace hydrogen and methane increased and correlated with changes in the microbial community structure. Enrichment of Pseudomonas spp. occurred with all lactate additions, and enrichment of sulfate-reducing Desulfosporosinus spp. occurred with almost complete sulfate reduction. The results of these experiments demonstrate that amendment with the pHRC and MRC forms result in effective removal of Cr(VI) from solution most likely by both direct (enzymatic) and indirect (microbially generated reductant) mechanisms.

  20. Aquatic community response in a groundwater-fed desert lake to Holocene desiccation of the Sahara

    Science.gov (United States)

    Eggermont, Hilde; Verschuren, Dirk; Fagot, Maureen; Rumes, Bob; Van Bocxlaer, Bert; Kröpelin, Stefan

    2008-12-01

    The finely laminated sediment record of a permanent, hypersaline, desert oasis lake in the Ounianga region of northeastern Chad presents a unique opportunity to document the hydrological evolution of this groundwater-fed aquatic ecosystem during mid- and late-Holocene desiccation of the Sahara. In this study we reconstruct long-term changes in zoobenthos and zooplankton communities of Lake Yoa as their early-Holocene freshwater habitat changed into the hypersaline conditions prevailing today. Chironomid production peaked during the fresh-to-saline transition period, then stabilized at about half that of the earlier freshwater ecosystem. Quantitative salinity inferences based on fossil chironomid assemblages indicate that the fresh-to-saline transition occurred fairly abruptly between ˜4100 and 3400 cal yr BP, but that the ecosystem was buffered against shorter-term climate fluctuations due to continuous inflow of fossil groundwater. The mixture of tropical-African and southern Palaearctic chironomid faunas in the Lake Yoa fossil record required us to address several methodological issues concerning chironomid-based salinity reconstruction, and the applicability of a calibration dataset based on tropical East and West African lakes to this Sahara desert locality. The most coherent reconstruction was obtained with an inference model that applies a weighted best-modern-analogue (WMAT) transfer function to the African calibration dataset expanded with six Sahara lakes.

  1. Groundwater arsenic contamination in one of the 107 arsenic-affected blocks in West Bengal, India: Status, distribution, health effects and factors responsible for arsenic poisoning.

    Science.gov (United States)

    Roychowdhury, Tarit

    2010-11-01

    A somewhat detailed study was carried out in Gaighata, one of the 107 arsenic-affected blocks in West Bengal, India, to determine the degree of groundwater contamination with arsenic, its depth wise distribution, correlation with iron, arsenical health effects to the inhabitants and the factors responsible for arsenic poisoning. Groundwater in all the 107 mouzas over 13 gram-panchayets in Gaighata block contains arsenic above 0.01mgl(-1) and in 91 mouzas, arsenic concentration has been found above 0.05mgl(-1). About 59.2 and 40.3% of the tubewell water samples contain arsenic above 0.01 and 0.05mgl(-1), respectively. The approximate population drinking arsenic-contaminated water above 0.01 and 0.05mgl(-1) are 106,560 and 72,540, respectively. The tubewells that were installed within the depth range of 15.4-30.3m are mostly arsenic-contaminated. Even the shallow groundwater level (7.87-15.1m) is arsenic-contaminated. Both arsenic and iron concentrations in groundwater gradually increase from lower depth to higher depth up to 39.4m, and then decrease with increasing depth. About 58% of the deep tubewell water samples (depth range 122-182m, n=31) contain arsenic ≥0.05mgl(-1). About 72% of the arsenic-contaminated deep tubewells (n=18) were safe when surveyed first time. But within a span of 2-5 years, they became contaminated with arsenic. The linear regression shows direct correlation between arsenic and iron concentrations in groundwater (r(2)=0.8114, parsenic from water by an adult male and female in the surveyed areas are 11.7 and 13.1μg/kg body wt./day, respectively and these values are higher than the WHO recommended PTDI value of inorganic arsenic (2.1μg/kg body wt./day). Mean arsenic concentrations in urine, hair and nail samples, collected from the inhabitants of Gutri mouza are higher than their normal level and the values are 292μgl(-1) (range: 8.35-1024μg l(-1), n=193), 2.50mgkg(-1) (range: 0.17-5.99mgkg(-1), n=132), and 6.05mgkg(-1) (range: 0

  2. Groundwater Recharge Evaluation in Semi-Arid Northeast Mexico in Response to Projected Climate Change

    Science.gov (United States)

    Wolaver, B. D.

    2007-12-01

    This research evaluates the effects of projected climate change on mountain recharge in the semi-arid Cuatrocinegas Basin (CCB) of northeast Mexico. The CCB UNESCO Biosphere Reserve is located in Coahuila, Mexico (~27° N, ~102° W) and includes > 500 springs that discharge from a regional flow system to wetlands with > 70 endemic species and to an irrigation network. This study tests the hypothesis that projected climate changes will reduce CCB recharge. In CCB, ~75% of annual precipitation (~220 mm at 700 m, ~400 mm at 2350 m) falls between May and October and ~40% falls during the North American Monsoon in June, July, and August. Environmental isotopes indicate aquifer residence times of > 50 years. Stable isotopes (O and H) show that mountain precipitation (at an elevation of ~1170 to 2350 m) dominates groundwater recharge. Recharge is insignificant at lower- elevation valleys that cover the majority of the study area due to high evapotranspiration rates. A Cl--balance water-budget recharge analysis estimates a spatially distributed recharge rate of ~1 to 3% of precipitation to provide at least 35x106 m3/year spring discharge (as measured in canals that drain dozens of springs). IPCC AR4 climate projections predict an annual temperature increase of 3.0 to 3.5°C and an annual precipitation decrease of 5 to 10% for Subregion CNA (located adjacent to CCB) by 2099. During June to August, models project a temperature increase of 3.5 to 4.0°C and a precipitation increase of 0 to 5%. Although global and regional circulation models evaluate mountain regions poorly, a first-order evaluation of climate projections on CCB recharge is needed input to develop effective long-term groundwater management policies. Climate projections suggest that the minimum elevation at which recharge occurs in CCB may increase by ~615 m to 1785 m, which would limit recharge to the highest mountain elevations. If annual precipitation is reduced by 5 to 10% and temperatures increase as

  3. Joint Assimilation of InSAR and Water-level Data for Aquifer Parameter Estimation and Groundwater State Forecasting in Santa Clara Valley, California

    Science.gov (United States)

    Abdullin, Ayrat; Jonsson, Sigurjon

    2017-04-01

    Ground subsidence induced by groundwater withdrawal is a widespread problem and can cause damage to buildings and infrastructure. The challenge is to forecast, accurately and in a cost effective way, when water extraction may threaten infrastructure, so that procedures can be applied to avoid unacceptable levels of ground deformation beyond construction engineering criteria. However, many characteristics of the heterogeneity of aquifer parameters, such as hydraulic conductivity and storage coefficients, are usually uncertain. Monitoring data, such as water-level data in monitoring wells, can be used to reduce these uncertainties, but the difficulty is that they usually only provide spatially limited information about the groundwater system. To take on these problems, we use an ensemble-based assimilation framework that efficiently integrates InSAR-derived displacements and hydraulic head data for improved understanding of groundwater reservoir behavior. We apply this framework for aquifer parameter estimation of the basin-wide Santa Clara Valley groundwater system in northern California. To study the deformation patterns in the area, we use time-series analysis of InSAR data, based on more than 150 images from the ERS, Envisat and ALOS satellites from 1992-2012. Using the InSAR observations, in addition to approximate data on pumping, managed recharge and rainfall amounts, we are able to advance our understanding of the ongoing hydrogeological processes within the aquifer system. We find that including both InSAR and well water-level data as observations improves the properties estimation compared to basic statistical interpolation between the available well data. We also compare the performance of our hydraulic head predictions with previous groundwater studies in Santa Clara Valley, such as those of Chaussard et al. (2014). The results suggest that the high spatial resolution subsidence observations from InSAR are useful for accurately quantifying hydraulic

  4. Culture, climate change and farm-level groundwater management: An Australian case study

    Science.gov (United States)

    Sanderson, Matthew R.; Curtis, Allen L.

    2016-05-01

    Cultural factors - values, beliefs, and norms - provide important insights into the environmental attitudes, risk perceptions, and behaviors of the general population. Little is known, however, about the ostensibly complex relationships linking those elements of culture to climate change risk perceptions, especially in the context of farm level decision in the ground water context. This paper addresses that gap through an analysis of survey data provided by irrigators in the Namoi catchment of Australia's Murray-Darling Basin. We use Values-Beliefs-Norms theory to construct multivariate models of the relationship between ground water irrigators' interpretations of climate change risks and their implementation of adaptive water conservation practices. Results indicate that these cultural factors are important explanations of irrigators' climate change risk perceptions, and these risk perceptions are related to adaptive ground water management strategies at the farm level. The implications of the findings are discussed for research on the culture-environment nexus and for outreach designed to encourage agricultural adaptations to climate change.

  5. Estimated 2008 groundwater potentiometric surface and predevelopment to 2008 water-level change in the Santa Fe Group aquifer system in the Albuquerque area, central New Mexico

    Science.gov (United States)

    Falk, Sarah E.; Bexfield, Laura M.; Anderholm, Scott K.

    2011-01-01

    The water-supply requirements of the Albuquerque metropolitan area of central New Mexico have historically been met almost exclusively by groundwater withdrawal from the Santa Fe Group aquifer system. Previous studies have indicated that the large quantity of groundwater withdrawal relative to recharge has resulted in water-level declines in the aquifer system throughout the metropolitan area. Analysis of the magnitude and pattern of water-level change can help improve understanding of how the groundwater system responds to withdrawals and variations in the management of the water supply and can support water-management agencies' efforts to minimize future water-level declines and improve sustainability. This report, prepared by the U.S. Geological Survey in cooperation with the Albuquerque Bernalillo County Water Utility Authority, presents the estimated groundwater potentiometric surface during winter (from December to March) of the 2008 water year and the estimated changes in water levels between predevelopment and water year 2008 for the production zone of the Santa Fe Group aquifer system in the Albuquerque and surrounding metropolitan and military areas. Hydrographs from selected wells are included to provide details of historical water-level changes. In general, water-level measurements used for this report were measured in small-diameter observation wells screened over short intervals and were considered to best represent the potentiometric head in the production zone-the interval of the aquifer, about 300 feet below land surface to 1,100 feet or more below land surface, in which production wells generally are screened. Water-level measurements were collected by various local and Federal agencies. The 2008 water year potentiometric surface map was created in a geographic information system, and the change in water-level elevation from predevelopment to water year 2008 was calculated. The 2008 water-level contours indicate that the general direction of

  6. Hanford Site ground-water monitoring for 1994

    Energy Technology Data Exchange (ETDEWEB)

    Dresel, P.E.; Thorne, P.D.; Luttrell, S.P. [and others

    1995-08-01

    This report presents the results of the Ground-Water Surveillance Project monitoring for calendar year 1994 on the Hanford Site, Washington. Hanford Site operations from 1943 onward produced large quantities of radiologic and chemical waste that have impacted ground-water quality on the Site. Monitoring of water levels and ground-water chemistry is performed to track the extent of contamination and trends in contaminant concentrations. The 1994 monitoring was also designed to identify emerging ground-water quality problems. The information obtained is used to verify compliance with applicable environmental regulations and to evaluate remedial actions. Data from other monitoring and characterization programs were incorporated to provide an integrated assessment of Site ground-water quality. Additional characterization of the Site`s geologic setting and hydrology was performed to support the interpretation of contaminant distributions. Numerical modeling of sitewide ground-water flow also supported the overall project goals. Water-level monitoring was performed to evaluate ground-water flow directions, to track changes in water levels, and to relate such changes to changes in site disposal practices. Water levels over most of the Hanford Site continued to decline between June 1993 and June 1994. These declines are part of the continued response to the cessation of discharge to U Pond and other disposal facilities. The low permeability in this area which enhanced mounding of waste-water discharge has also slowed the response to the reduction of disposal.

  7. Linking soil moisture balance and source-responsive models to estimate diffuse and preferential components of groundwater recharge

    Science.gov (United States)

    Cuthbert, M.O.; Mackay, R.; Nimmo, J.R.

    2012-01-01

    Results are presented of a detailed study into the vadose zone and shallow water table hydrodynamics of a field site in Shropshire, UK. A conceptual model is developed and tested using a range of numerical models, including a modified soil moisture balance model (SMBM) for estimating groundwater recharge in the presence of both diffuse and preferential flow components. Tensiometry reveals that the loamy sand topsoil wets up via macropore flow and subsequent redistribution of moisture into the soil matrix. Recharge does not occur until near-positive pressures are achieved at the top of the sandy glaciofluvial outwash material that underlies the topsoil, about 1 m above the water table. Once this occurs, very rapid water table rises follow. This threshold behaviour is attributed to the vertical discontinuity in the macropore system due to seasonal ploughing of the topsoil, and a lower permeability plough/iron pan restricting matrix flow between the topsoil and the lower outwash deposits. Although the wetting process in the topsoil is complex, a SMBM is shown to be effective in predicting the initiation of preferential flow from the base of the topsoil into the lower outwash horizon. The rapidity of the response at the water table and a water table rise during the summer period while flow gradients in the unsaturated profile were upward suggest that preferential flow is also occurring within the outwash deposits below the topsoil. A variation of the source-responsive model proposed by Nimmo (2010) is shown to reproduce the observed water table dynamics well in the lower outwash horizon when linked to a SMBM that quantifies the potential recharge from the topsoil. The results reveal new insights into preferential flow processes in cultivated soils and provide a useful and practical approach to accounting for preferential flow in studies of groundwater recharge estimation.

  8. Linking soil moisture balance and source-responsive models to estimate diffuse and preferential components of groundwater recharge

    Directory of Open Access Journals (Sweden)

    M. O. Cuthbert

    2013-03-01

    Full Text Available Results are presented of a detailed study into the vadose zone and shallow water table hydrodynamics of a field site in Shropshire, UK. A conceptual model is presented and tested using a range of numerical models, including a modified soil moisture balance model (SMBM for estimating groundwater recharge in the presence of both diffuse and preferential flow components. Tensiometry reveals that the loamy sand topsoil wets up via preferential flow and subsequent redistribution of moisture into the soil matrix. Recharge does not occur until near-positive pressures are achieved at the top of the sandy glaciofluvial outwash material that underlies the topsoil, about 1 m above the water table. Once this occurs, very rapid water table rises follow. This threshold behaviour is attributed to the vertical discontinuity in preferential flow pathways due to seasonal ploughing of the topsoil and to a lower permeability plough/iron pan restricting matrix flow between the topsoil and the lower outwash deposits. Although the wetting process in the topsoil is complex, a SMBM is shown to be effective in predicting the initiation of preferential flow from the base of the topsoil into the lower outwash horizon. The rapidity of the response at the water table and a water table rise during the summer period while flow gradients in the unsaturated profile were upward suggest that preferential flow is also occurring within the outwash deposits below the topsoil. A variation of the source-responsive model proposed by Nimmo (2010 is shown to reproduce the observed water table dynamics well in the lower outwash horizon when linked to a SMBM that quantifies the potential recharge from the topsoil. The results reveal new insights into preferential flow processes in cultivated soils and provide a useful and practical approach to accounting for preferential flow in studies of groundwater recharge estimation.

  9. Numerical simulation of saltwater intrusion in response to sea-level rise

    Science.gov (United States)

    Langevin, C.D.; Dausman, A.M.

    2005-01-01

    A two dimensional numerical model of variable-density groundwater flow and dispersive solute transport was used to predict the extent, rate, and lag time of saltwater intrusion in response to various sea-level rise scenarios. Three simulations were performed with varying rates of sea-level rise. For the first simulation, sea-level rise was specified at a rate of 0.9 mm/yr, which is the slowest rate of sea-level rise estimated by the Intergovernmental Panel on Climate Change (IPCC). After 100 years, the 250 mg/L chloride isochlor moved inland by about 40 m, and required an additional 8 years for the system to reach equilibrium. For the next simulation, sea-level rise was specified at 4.8 mm/yr, which is the central value of the IPCC estimate. For this moderate rate of sea-level rise, the 250 mg/L isochlor moved inland by about 740 m after 100 years, and required an additional 10 years for the system to reach equilibrium. For the fastest rate of sea level rise estimated by IPCC (8.8 mm/yr), the 250 mg/L isochlor moved inland by about 1800 m after 100 years, and required more than 50 years to reach equilibrium. Copyright ASCE 2005.

  10. 不同潜水埋深下土壤水盐运移特征及其交互效应%Migration characteristics of soil water and salt and their interaction under different groundwater levels

    Institute of Scientific and Technical Information of China (English)

    夏江宝; 赵西梅; 赵自国; 陈印平; 刘俊华

    2015-01-01

    为探讨盐水矿化度下土壤水盐分布特征对潜水埋深的响应规律及其水盐交互效应,以黄河三角洲建群种柽柳(Tamarix chinensis Lour)栽植的土壤柱体为研究对象,模拟设置0.3、0.6、0.9、1.2、1.5和1.8 m共6种潜水水位,测定分析各水位处理下不同土壤剖面的相对含水率、含盐量及土壤溶液绝对浓度等水盐参数。结果表明:随潜水水位的增加,整个土柱水分均值显著降低,土壤含盐量和溶液绝对浓度均值先升高后降低,1.2 m水位是土壤水盐变化的转折点,此水位下各土壤剖面的含盐量和土壤溶液绝对浓度均达最高。土柱水分和盐分变化幅度最大的水位分别在中水位0.9~1.2 m,浅水位0.6 m,土壤溶液绝对浓度变化最剧烈的是深水位1.5~1.8 m。随土壤深度的增加,土壤水分显著升高,土壤盐分先降低后升高,表土层盐分均值最高达1.36%,但土壤溶液绝对浓度显著减小。土壤含盐量、土壤相对含水率与潜水水位分别呈极显著(P<0.01)和显著(P<0.05)负相关,土壤相对含水率与盐分呈极显著正相关(P<0.01)。地下盐水矿化度下,柽柳幼苗栽植深度应超过20 cm深,适宜潜水水位在1.5~1.8 m,栽植深度以30~40 cm较好。研究结果可为地下盐水作用条件下土壤次生盐渍化的防治和柽柳栽植管理提供参考。%Soil salt and water closely related to groundwater depth mainly affect vegetation distribution pattern and community succession of the Yellow River Delta. Thus,it is important to explain the changing process of water and salt in groundwater and soil and their effects on the occurrence of the secondary salinization. This study aimed to understand the response of soil water-salt distribution characteristics to groundwater depth and their interactive effects under saline groundwater conditions. To achieve the objective, a laboratory experiment was

  11. Groundwater flow modeling of periods with periglacial and glacial climate conditions for the safety assessment of the proposed high-level nuclear waste repository site at Forsmark, Sweden

    Science.gov (United States)

    Vidstrand, Patrik; Follin, Sven; Selroos, Jan-Olof; Näslund, Jens-Ove

    2014-09-01

    The impact of periglacial and glacial climate conditions on groundwater flow in fractured crystalline rock is studied by means of groundwater flow modeling of the Forsmark site, which was recently proposed as a repository site for the disposal of spent high-level nuclear fuel in Sweden. The employed model uses a thermal-hydraulically coupled approach for permafrost modeling and discusses changes in groundwater flow implied by the climate conditions found over northern Europe at different times during the last glacial cycle (Weichselian glaciation). It is concluded that discharge of particles released at repository depth occurs very close to the ice-sheet margin in the absence of permafrost. If permafrost is included, the greater part discharges into taliks in the periglacial area. During a glacial cycle, hydraulic gradients at repository depth reach their maximum values when the ice-sheet margin passes over the site; at this time, also, the interface between fresh and saline waters is distorted the most. The combined effect of advances and retreats during several glaciations has not been studied in the present work; however, the results indicate that hydrochemical conditions at depth in the groundwater flow model are almost restored after a single event of ice-sheet advance and retreat.

  12. Surface- and ground-water relations on the Portneuf river, and temporal changes in ground-water levels in the Portneuf Valley, Caribou and Bannock Counties, Idaho, 2001-02

    Science.gov (United States)

    Barton, Gary J.

    2004-01-01

    high flows. Conveyance losses in the Pebble-Topaz reach were greatest, about 283 cubic feet per second, during the spring regulated high flows and were attributed to a hydroelectric project.Comparison of water levels in 30 wells in the Portneuf Valley during September and October 1968 and 2001 indicated long-term declines since 1968; the median decline was 3.4 feet. September and October were selected for characterizing long-term ground-water-level fluctuations because declines associated with irrigation reach a maximum at the end of the irrigation season. The average annual snowpack in the study area has declined significantly; 1945 85 average annual snowpack was 16.1 inches, whereas 1986 through 2002 average annual snowpack was 11.6 inches. Water-level declines during 1998 2002 may be partially attributable to the extended dry climatic conditions. It is unclear whether the declines could be partially attributed to increases in ground-water withdrawals. Between 1968 and 1980, water rights for ground-water withdrawals nearly doubled from 23,500 to 46,000 acre-feet per year. During this period, ground-water levels were relatively constant and did not exhibit a declining trend that could be related to increased ground-water withdrawal rights. However, ground-water withdrawals are not measured in the valley; thus, the amount of water pumped is not known. Since the 1990s, there have been several years when the Chesterfield Reservoir has not completely refilled, and the water in storage behind the reservoir has been depleted by the middle of the irrigation season. In this situation, surface-water diversions for irrigation were terminated before the end of the irrigation season, and irrigators, who were relying in part on diversions from the Portneuf River, had to rely solely on ground water as an alternate supply. Smaller volumes of water in the Chesterfield Reservoir since the 1990s indicate a growing demand for ground-water supplies.

  13. Declining Groundwater Levels in North India: Understanding Sources of Irrigation Inefficiency

    Science.gov (United States)

    O'Keeffe, J.; Buytaert, W.; Mijic, A.; Brozovic, N.

    2014-12-01

    Over the last half century, the green revolution has transformed India from a famine-prone, drought-susceptible country, into the world's third largest grain producer and one of the most intensely irrigated regions on the planet. This is in no small part due to the country's vast water resources along with an increase in tubewells and more advanced abstraction methods. While agricultural intensification has had undeniable benefits, it has, and continues to have a significant impact on water resources. Unless solutions which take into consideration the ever evolving socio-economic, hydrological and climatic conditions are found, India's agricultural future looks bleak.This research examines the irrigation behaviour of farmers, using data collected during field work in the State of Uttar Pradesh within the Ganges Basin of North India. Significant differences in farmer behaviour and irrigation practices are highlighted, not only between State districts but between individual farmers. This includes the volume of irrigation water applied and the price paid, as well as differences in the yields of crops produced. Analyses of results suggest that this is due to a number of factors, particularly the source of irrigation water. Study areas which had access to cheaper, but crucially less reliable, canal water were found to invest in more efficient water saving technologies in order to reduce the overall cost of irrigation during periods where less expensive canal water is not available. As a result, overall water use and irrigation cost is lower and yields are higher despite very similar climatic conditions. While cheap canal water is not an option for all farmers, the results show that the introduction of more efficient water saving technologies, despite the significant capital expenditure is a viable option for many farmers and costs can be recovered in a relatively short space of time. In addition, the reduction of declining water levels mean that water is abstracted from

  14. Groundwater dynamic, temperature and salinity response to the tide in Patagonian marshes: Observations on a coastal wetland in San José Gulf, Argentina

    Science.gov (United States)

    Alvarez, María del Pilar; Carol, Eleonora; Hernández, Mario A.; Bouza, Pablo J.

    2015-10-01

    The processes regulating the relationship between tidal flows and shallow groundwater dynamics, temperature and salinity in a coastal wetland in an arid climate are analysed in a detailed field study carried out in the marsh located at Playa Fracasso (Argentina). The continuous records of groundwater level, temperature and electrical conductivity from a transect perpendicular to the coastline were studied during a period ranging from summer to winter, together with the information obtained in hydrogeomorphological field surveys and soil profiles. An assessment of the processes conditioning marsh hydrology was carried out contemplating seasonal (summer-winter) and periodical variations caused by tidal flows. The study showed that the dynamics of groundwater in relation to tidal flows depends almost exclusively on the infiltration of tidal water when the marsh is flooded during spring tides (syzygy), with an increase in the groundwater discharge level at the onset of syzygy. The differences in temperature between sea and continental water were very useful in defining the origin of the different contributions. Groundwater salinity is mainly associated with the leaching of the soil salts that enter with the sea water infiltrating during flood events. The presence of saline soils in the marsh is regulated by the evapotranspiration predominating in arid zones. The conceptual hydrological model suggested may help in the understanding of the hydrological processes in other similar marshes of Patagonia, as well as in coastal wetlands of arid zones worldwide.

  15. Regional differences in climate change impacts on groundwater and stream discharge in Denmark

    DEFF Research Database (Denmark)

    Van Roosmalen, Lieke Petronella G; Christensen, Britt S.B.; Sonnenborg, Torben O.

    2007-01-01

    groundwater-river interaction. On Sjaelland, where the topsoil is dominated by low-permeability soils and the aquifers are protected by thick clay layers of regional extent, only minor changes in groundwater levels are predicted. The primary effect in this area is the change in stream discharge, caused...... of the hydrological response to the simulated climate change is highly dependant on the geological setting of the model area. In the Jylland area, characterized by sandy top soils and large interconnected aquifers, groundwater recharge increases significantly, resulting in higher groundwater levels and increasing...

  16. Questa baseline and pre-mining ground-water quality investigation. 5. Well installation, water-level data, and surface- and ground-water geochemistry in the Straight Creek drainage basin, Red River Valley, New Mexico, 2001-03

    Science.gov (United States)

    Naus, Cheryl A.; McCleskey, R. Blaine; Nordstrom, D. Kirk; Donohoe, Lisa C.; Hunt, Andrew G.; Paillet, Frederick L.; Morin, Roger H.; Verplanck, Philip L.

    2005-01-01

    The U.S. Geological Survey, in cooperation with the New Mexico Environment Department, is investigating the pre-mining ground-water chemistry at the Molycorp molybdenum mine in the Red River Valley, northern New Mexico. The primary approach is to determine the processes controlling ground-water chemistry at an unmined, off-site, proximal analog. The Straight Creek drainage basin, chosen for this purpose, consists of the same quartz-sericite-pyrite altered andesitic and rhyolitic volcanic rock of Tertiary age as the mine site. The weathered and rugged volcanic bedrock surface is overlain by heterogeneous debris-flow deposits that interfinger with alluvial deposits near the confluence of Straight Creek and the Red River. Pyritized rock in the upper part of the drainage basin is the source of acid rock drainage (pH 2.8-3.3) that infiltrates debris-flow deposits containing acidic ground water (pH 3.0-4.0) and bedrock containing water of circumneutral pH values (5.6-7.7). Eleven observation wells were installed in the Straight Creek drainage basin. The wells were completed in debris-flow deposits, bedrock, and interfingering debris-flow and Red River alluvial deposits. Chemical analyses of ground water from these wells, combined with chemical analyses of surface water, water-level data, and lithologic and geophysical logs, provided information used to develop an understanding of the processes contributing to the chemistry of ground water in the Straight Creek drainage basin. Surface- and ground-water samples were routinely collected for determination of total major cations and selected trace metals; dissolved major cations, selected trace metals, and rare-earth elements; anions and alkalinity; and dissolved-iron species. Rare-earth elements were determined on selected samples only. Samples were collected for determination of dissolved organic carbon, mercury, sulfur isotopic composition (34S and 18O of sulfate), and water isotopic composition (2H and 18O) during

  17. Identification and level of organochlorine insecticide contamination in groundwater and iridology analysis for people in Upper Citarum cascade

    Science.gov (United States)

    Oginawati, K.; Pratama, M. A.

    2016-03-01

    Organochlorines are the main pollutants in the class of persistent organic pollutants which are types of pollutants that are being questioned worldwide due to chronic persistence, toxicity and bioaccumulation. Human around the Citarum River are still using groundwater as a drinking source. It is very risky for people health that consume groundwater because in 2009 the application of organochlorine still found in the Upper Citarum watershed rice field and had potential to contaminate groundwater. Groundwater was analyzed with nine species belonging to the organochlorine pollutants Organic Peristent types. 7 types of organochlorinesAldrin was detected with an average concentration of 0.09 ppb, dieldrin with an average concentration of 24 ppb, heptaklor with an average concentration of 0.51 ppb, with concentrations of endosulfan on average 0.73 ppb, DDT with average concentration of 0.13 ppb, Lindan with an average concentration of 1.2 ppb, endrin with an average concentration of 0.03 ppb. Types with the highest concentration of organochlorine a lindan and endosulfan. Residues of aldrin, dieldrin and heptaklor in groundwater already exceeds the quality standards for drinking water Permenkes 492/2010. Based on the iridology analysis obtained several systems are expected to nervous, immune and reproductive system disorders and toxin deposits under the skin.

  18. Implementing groundwater extraction in life cycle impact assessment: characterization factors based on plant species richness for The Netherlands.

    Science.gov (United States)

    van Zelm, Rosalie; Schipper, Aafke M; Rombouts, Michiel; Snepvangers, Judith; Huijbregts, Mark A J

    2011-01-15

    An operational method to evaluate the environmental impacts associated with groundwater use is currently lacking in life cycle assessment (LCA). This paper outlines a method to calculate characterization factors that address the effects of groundwater extraction on the species richness of terrestrial vegetation. Characterization factors (CF) were derived for The Netherlands and consist of a fate and an effect part. The fate factor equals the change in drawdown due to a change in groundwater extraction and expresses the amount of time required for groundwater replenishment. It was obtained with a grid-specific steady-state groundwater flow model. Effect factors were obtained from groundwater level response curves of potential plant species richness, which was constructed based on the soil moisture requirements of 625 plant species. Depending on the initial groundwater level, effect factors range up to 9.2% loss of species per 10 cm of groundwater level decrease. The total Dutch CF for groundwater extraction depended on the value choices taken and ranged from 0.09 to 0.61 m(2)·yr/m(3). For tap water production, we showed that groundwater extraction can be responsible for up to 32% of the total terrestrial ecosystem damage. With the proposed approach, effects of groundwater extraction on terrestrial ecosystems can be systematically included in LCA.

  19. Discussion on the Initial Water Level of Groundwater%关于地下水初见水位的讨论

    Institute of Scientific and Technical Information of China (English)

    尤苏南

    2012-01-01

    This paper presents the analysis and discussion on initial water level of groundwater according to different understanding offered by investigation competitors; besides, it also puts forward the author's own ideas for colleagues in reference.%针对勘察同行们对地下水初见水位的不同理解,进行分析和讨论,提出了自己的看法,可供勘察同行们工作中参考.

  20. Geostatistical analysis of groundwater level using Euclidean and non-Euclidean distance metrics and variable variogram fitting criteria

    Science.gov (United States)

    Theodoridou, Panagiota G.; Karatzas, George P.; Varouchakis, Emmanouil A.; Corzo Perez, Gerald A.

    2015-04-01

    Groundwater level is an important information in hydrological modelling. Geostatistical methods are often employed to map the free surface of an aquifer. In geostatistical analysis using Kriging techniques the selection of the optimal variogram model is very important for the optimal method performance. This work compares three different criteria, the least squares sum method, the Akaike Information Criterion and the Cressie's Indicator, to assess the theoretical variogram that fits to the experimental one and investigates the impact on the prediction results. Moreover, five different distance functions (Euclidean, Minkowski, Manhattan, Canberra, and Bray-Curtis) are applied to calculate the distance between observations that affects both the variogram calculation and the Kriging estimator. Cross validation analysis in terms of Ordinary Kriging is applied by using sequentially a different distance metric and the above three variogram fitting criteria. The spatial dependence of the observations in the tested dataset is studied by fitting classical variogram models and the Matérn model. The proposed comparison analysis performed for a data set of two hundred fifty hydraulic head measurements distributed over an alluvial aquifer that covers an area of 210 km2. The study area is located in the Prefecture of Drama, which belongs to the Water District of East Macedonia (Greece). This area was selected in terms of hydro-geological data availability and geological homogeneity. The analysis showed that a combination of the Akaike information Criterion for the variogram fitting assessment and the Brays-Curtis distance metric provided the most accurate cross-validation results. The Power-law variogram model provided the best fit to the experimental data. The aforementioned approach for the specific dataset in terms of the Ordinary Kriging method improves the prediction efficiency in comparison to the classical Euclidean distance metric. Therefore, maps of the spatial

  1. Estimating hydraulic parameters of a heterogeneous aquitard using long-term multi-extensometer and groundwater level data

    Science.gov (United States)

    Zhuang, Chao; Zhou, Zhifang; Illman, Walter A.; Guo, Qiaona; Wang, Jinguo

    2017-05-01

    The classical aquitard-drainage model COMPAC has been modified to simulate the compaction process of a heterogeneous aquitard consisting of multiple sub-units (Multi-COMPAC). By coupling Multi-COMPAC with the parameter estimation code PEST++, the vertical hydraulic conductivity (K v) and elastic (S ske) and inelastic (S skp) skeletal specific-storage values of each sub-unit can be estimated using observed long-term multi-extensometer and groundwater level data. The approach was first tested through a synthetic case with known parameters. Results of the synthetic case revealed that it was possible to accurately estimate the three parameters for each sub-unit. Next, the methodology was applied to a field site located in Changzhou city, China. Based on the detailed stratigraphic information and extensometer data, the aquitard of interest was subdivided into three sub-units. Parameters K v, S ske and S skp of each sub-unit were estimated simultaneously and then were compared with laboratory results and with bulk values and geologic data from previous studies, demonstrating the reliability of parameter estimates. Estimated S skp values ranged within the magnitude of 10-4 m-1, while K v ranged over 10-10-10-8 m/s, suggesting moderately high heterogeneity of the aquitard. However, the elastic deformation of the third sub-unit, consisting of soft plastic silty clay, is masked by delayed drainage, and the inverse procedure leads to large uncertainty in the S ske estimate for this sub-unit.

  2. Estimating hydraulic parameters of a heterogeneous aquitard using long-term multi-extensometer and groundwater level data

    Science.gov (United States)

    Zhuang, Chao; Zhou, Zhifang; Illman, Walter A.; Guo, Qiaona; Wang, Jinguo

    2017-09-01

    The classical aquitard-drainage model COMPAC has been modified to simulate the compaction process of a heterogeneous aquitard consisting of multiple sub-units (Multi-COMPAC). By coupling Multi-COMPAC with the parameter estimation code PEST++, the vertical hydraulic conductivity ( K v) and elastic ( S ske) and inelastic ( S skp) skeletal specific-storage values of each sub-unit can be estimated using observed long-term multi-extensometer and groundwater level data. The approach was first tested through a synthetic case with known parameters. Results of the synthetic case revealed that it was possible to accurately estimate the three parameters for each sub-unit. Next, the methodology was applied to a field site located in Changzhou city, China. Based on the detailed stratigraphic information and extensometer data, the aquitard of interest was subdivided into three sub-units. Parameters K v, S ske and S skp of each sub-unit were estimated simultaneously and then were compared with laboratory results and with bulk values and geologic data from previous studies, demonstrating the reliability of parameter estimates. Estimated S skp values ranged within the magnitude of 10-4 m-1, while K v ranged over 10-10-10-8 m/s, suggesting moderately high heterogeneity of the aquitard. However, the elastic deformation of the third sub-unit, consisting of soft plastic silty clay, is masked by delayed drainage, and the inverse procedure leads to large uncertainty in the S ske estimate for this sub-unit.

  3. Occurrence of nitrate in Tanzanian groundwater aquifers: A review

    Science.gov (United States)

    Elisante, Eliapenda; Muzuka, Alfred N. N.

    2017-03-01

    More than 25 % of Tanzanian depends on groundwater as the main source of water for drinking, irrigation and industrial activities. The current trend of land use may lead to groundwater contamination and thus increasing risks associated with the usage of contaminated water. Nitrate is one of the contaminants resulting largely from anthropogenic activities that may find its way to the aquifers and thus threatening the quality of groundwater. Elevated levels of nitrate in groundwater may lead to human health and environmental problems. The current trend of land use in Tanzania associated with high population growth, poor sanitation facilities and fertilizer usage may lead to nitrate contamination of groundwater. This paper therefore aimed at providing an overview of to what extent human activities have altered the concentration of nitrate in groundwater aquifers in Tanzania. The concentration of nitrate in Tanzanian groundwater is variable with highest values observable in Dar es Salaam (up to 477.6 mg/l), Dodoma (up to 441.1 mg/l), Tanga (above 100 mg/l) and Manyara (180 mg/l). Such high values can be attributed to various human activities including onsite sanitation in urban centres and agricultural activities in rural areas. Furthermore, there are some signs of increasing concentration of nitrate in groundwater with time in some areas in response to increased human activities. However, reports on levels and trends of nitrate in groundwater in many regions of the country are lacking. For Tanzania to appropriately address the issue of groundwater contamination, a deliberate move to determine nitrate concentration in groundwater is required, as well as protection of recharge basins and improvement of onsite sanitation systems.

  4. Occurrence of nitrate in Tanzanian groundwater aquifers: A review

    Science.gov (United States)

    Elisante, Eliapenda; Muzuka, Alfred N. N.

    2015-03-01

    More than 25 % of Tanzanian depends on groundwater as the main source of water for drinking, irrigation and industrial activities. The current trend of land use may lead to groundwater contamination and thus increasing risks associated with the usage of contaminated water. Nitrate is one of the contaminants resulting largely from anthropogenic activities that may find its way to the aquifers and thus threatening the quality of groundwater. Elevated levels of nitrate in groundwater may lead to human health and environmental problems. The current trend of land use in Tanzania associated with high population growth, poor sanitation facilities and fertilizer usage may lead to nitrate contamination of groundwater. This paper therefore aimed at providing an overview of to what extent human activities have altered the concentration of nitrate in groundwater aquifers in Tanzania. The concentration of nitrate in Tanzanian groundwater is variable with highest values observable in Dar es Salaam (up to 477.6 mg/l), Dodoma (up to 441.1 mg/l), Tanga (above 100 mg/l) and Manyara (180 mg/l). Such high values can be attributed to various human activities including onsite sanitation in urban centres and agricultural activities in rural areas. Furthermore, there are some signs of increasing concentration of nitrate in groundwater with time in some areas in response to increased human activities. However, reports on levels and trends of nitrate in groundwater in many regions of the country are lacking. For Tanzania to appropriately address the issue of groundwater contamination, a deliberate move to determine nitrate concentration in groundwater is required, as well as protection of recharge basins and improvement of onsite sanitation systems.

  5. Limits to Global Groundwater Consumption

    Science.gov (United States)

    Graaf, I. D.; Van Beek, R.; Sutanudjaja, E.; Wada, Y.; Bierkens, M. F.

    2015-12-01

    In regions with frequent water stress and large aquifer systems, groundwater is often used as an additional fresh water source. For many regions of the world groundwater abstraction exceeds groundwater recharge and persistent groundwater depletion occurs. The most direct effect of groundwater depletion is declining of water tables, leading to reduced groundwater discharge needed to sustain base-flow to e.g. rivers. Next to that, pumping costs increase, wells dry up and land subsidence occurs. These problems are expected to increase in the near future due to growing population and climate changes. This poses the urgent question of what the limits are of groundwater consumption worldwide. We simulate global water availability (5 arc-minute resolution, for 1960-2050) using the hydrological model PCR-GLOBWB (van Beek et al. 2011), coupled to a groundwater model based on MODFLOW (de Graaf et al. 2015), allowing for groundwater - surface water interactions. The groundwater model includes a parameterization of world's confined and unconfined aquifer systems needed for a realistic simulation of groundwater head dynamics. Water demands are included (from Wada et al. 2014). We study the limits to water consumption, focusing on locally attainable groundwater and groundwater levels critical to rivers to sustain low flows. We show an increasing trend (1960-2050) in groundwater head declines, due to increase in groundwater demand. Also, stream flow will decrease and low flow conditions will occur more frequent and will be longer in duration in the near future, especially for irrigated areas. Next to that, we provide a global overview of the years it takes until groundwater gets unattainable for e.g. a local farmer (100 m below land-surface used as a proxy), and estimate the increase in pumping cost for the near future. The results show where and when limits of groundwater consumption are reached globally.

  6. Evaluation of levels of antibiotic resistance in groundwater-derived E. coli isolates in the Midwest of Ireland and elucidation of potential predictors of resistance

    Science.gov (United States)

    O'Dwyer, Jean; Hynds, Paul; Pot, Matthieu; Adley, Catherine C.; Ryan, Michael P.

    2017-06-01

    Antibiotic-resistant (pathogenic and non-pathogenic) organisms and genes are now acknowledged as significant emerging aquatic contaminants with potentially adverse human and ecological health impacts, and thus require monitoring. This study is the first to investigate levels of resistance among Irish groundwater (private wells) samples; Escherichia coli isolates were examined against a panel of commonly prescribed human and veterinary therapeutic antibiotics, followed by determination of the causative factors of resistance. Overall, 42 confirmed E. coli isolates were recovered from a groundwater-sampling cohort. Resistance to the human panel of antibiotics was moderate; nine (21.4%) E. coli isolates demonstrated resistance to one or more human antibiotics. Conversely, extremely high levels of resistance to veterinary antibiotics were found, with all isolates presenting resistance to one or more veterinary antibiotics. Particularly high levels of resistance (93%) were found with respect to the aminoglycoside class of antibiotics. Results of statistical analysis indicate a significant association between the presence of human (multiple) antibiotic resistance ( p = 0.002-0.011) and both septic tank density and the presence of vulnerable sub-populations (antibiotics, results point to a significant relationship ( p = antibiotic resistant E. coli. Groundwater continues to be an important resource in Ireland, particularly in rural areas; thus, results of this preliminary study offer a valuable insight into the prevalence of antibiotic resistance in the hydrogeological environment and establish a need for further research with a larger geological diversity.

  7. Groundwater management for agriculture and nature: an economic analysis

    NARCIS (Netherlands)

    Hellegers, P.J.G.J.

    2001-01-01

    Key words: desiccation of nature, economics of water management, groundwater extraction, groundwater level management, ecohydrology, agriculture, policy instruments.

    As a result of declining groundwater levels, nature in the Netherlands is suffering

  8. Groundwater Management for Agriculture and Nature : an Economic Analysis

    NARCIS (Netherlands)

    Hellegers, P.

    2001-01-01

    Key words: desiccation of nature, economics of water management, groundwater extraction, groundwater level management, ecohydrology, agriculture, policy instruments.As a result of declining groundwater levels, nature in the Netherlands is suffering from desiccation. Since measures taken to raise gro

  9. Groundwater sustainability assessment in coastal aquifers

    Indian Academy of Sciences (India)

    U A Lathashri; A Mahesha

    2016-08-01

    The present work investigates the response of shallow, coastal unconfined aquifers to anticipated overdraft conditions and climate change effect using numerical simulation. The groundwater flow model MODFLOW and variable density groundwater model SEAWAT are used for this investigation. The transmissivity and specific yield estimated from the existing database range from 10 to 810 m^2/day and 0.08% to 10.92% respectively. After successful calibration with Nash–Sutcliffe efficiency greater than 0.80, the values of horizontal hydraulic conductivity and specific yield of the unconfined aquifer were set in the range 1.85–61.90 m/day and 0.006–0.24 respectively. After validating the model, it is applied for forecasting the aquifer’s response to anticipated future scenarios of groundwater draft, recharge rate and sea level rise. The findings of the study illustrate that saltwater intrusion is intensified in the area adjoining the tidal rivers, rather than that due to the sea alone. Of all the scenarios simulated, the immense negative impact on groundwater quality emerges due to overdraft conditions and reduced recharge with the areal extent of seawater intrusion exceeding about 67% (TDS>1 kg/m^3). The study also arrivesat the conclusion that, regional sea level rise of 1 mm/year has no impact on the groundwater dynamics of the aquifer.

  10. Effects of groundwater levels and headwater wetlands on streamflow in the Charlie Creek basin, Peace River watershed, west-central Florida

    Science.gov (United States)

    Lee, T.M.; Sacks, L.A.; Hughes, J.D.

    2010-01-01

    The Charlie Creek basin was studied from April 2004 to December 2005 to better understand how groundwater levels in the underlying aquifers and storage and overflow of water from headwater wetlands preserve the streamflows exiting this least-developed tributary basin of the Peace River watershed. The hydrogeologic framework, physical characteristics, and streamflow were described and quantified for five subbasins of the 330-square mile Charlie Creek basin, allowing the contribution of its headwaters area and tributary subbasins to be separately quantified. A MIKE SHE model simulation of the integrated surface-water and groundwater flow processes in the basin was used to simulate daily streamflow observed over 21 months in 2004 and 2005 at five streamflow stations, and to quantify the monthly and annual water budgets for the five subbasins including the changing amount of water stored in wetlands. Groundwater heads were mapped in Zone 2 of the intermediate aquifer system and in the Upper Floridan aquifer, and were used to interpret the location of artesian head conditions in the Charlie Creek basin and its relation to streamflow. Artesian conditions in the intermediate aquifer system induce upward groundwater flow into the surficial aquifer and help sustain base flow which supplies about two-thirds of the streamflow from the Charlie Creek basin. Seepage measurements confirmed seepage inflow to Charlie Creek during the study period. The upper half of the basin, comprised largely of the Upper Charlie Creek subbasin, has lower runoff potential than the lower basin, more storage of runoff in wetlands, and periodically generates no streamflow. Artesian head conditions in the intermediate aquifer system were widespread in the upper half of the Charlie Creek basin, preventing downward leakage from expansive areas of wetlands and enabling them to act as headwaters to Charlie Creek once their storage requirements were met. Currently, the dynamic balance between wetland

  11. Baseline Response Levels Are a Nuisance in Infant Contingency Learning

    Science.gov (United States)

    Millar, W. S.; Weir, Catherine

    2015-01-01

    The impact of differences in level of baseline responding on contingency learning in the first year was examined by considering the response acquisition of infants classified into baseline response quartiles. Whereas the three lower baseline groups showed the predicted increment in responding to a contingency, the highest baseline responders did…

  12. MODFLOW-NWT model used to evaluate the potential effect of groundwater pumpage and increased sea level on canal leakage and regional groundwater flow in Miami-Dade County, Florida

    Data.gov (United States)

    U.S. Geological Survey, Department of the Interior — A three-dimensional, surface-water/groundwater model (MODFLOW-NWT with the Surface-Water Routing Process) was developed to the predict the effects of groundwater...

  13. MANAGEMENT MODEL OF UNCONFINED AQUIFER SYSTEM WITH SMALL THICKNESS WITH RESPECT TO DRAWDOWN BASED ON TWO-LEVEL RESPONSE MATRIX

    Institute of Scientific and Technical Information of China (English)

    Cai-Zhi SUN; Wei ZOU; Xue-Yu LIN

    2004-01-01

    In the management of unconfined aquifer systems, if the thickness of the aquifer is very small and the drawdown is relatively big, errors may arise when the superposition principle is adopted.directly. In allusion to this limitation, a new management model for the management of unconfined aquifer systems called two-level response matrix method is put forward. This method is applied in groundwater resources management in Shenyang city. The managing results show that this methodcan, in some degree, increase the efficiency of management and decrease the risk of management.

  14. Numerical groundwater-flow modeling to evaluate potential effects of pumping and recharge: implications for sustainable groundwater management in the Mahanadi delta region, India

    Science.gov (United States)

    Sahoo, Sasmita; Jha, Madan K.

    2017-07-01

    Process-based groundwater models are useful to understand complex aquifer systems and make predictions about their response to hydrological changes. A conceptual model for evaluating responses to environmental changes is presented, considering the hydrogeologic framework, flow processes, aquifer hydraulic properties, boundary conditions, and sources and sinks of the groundwater system. Based on this conceptual model, a quasi-three-dimensional transient groundwater flow model was designed using MODFLOW to simulate the groundwater system of Mahanadi River delta, eastern India. The model was constructed in the context of an upper unconfined aquifer and lower confined aquifer, separated by an aquitard. Hydraulic heads of 13 shallow wells and 11 deep wells were used to calibrate transient groundwater conditions during 1997-2006, followed by validation (2007-2011). The aquifer and aquitard hydraulic properties were obtained by pumping tests and were calibrated along with the rainfall recharge. The statistical and graphical performance indicators suggested a reasonably good simulation of groundwater flow over the study area. Sensitivity analysis revealed that groundwater level is most sensitive to the hydraulic conductivities of both the aquifers, followed by vertical hydraulic conductivity of the confining layer. The calibrated model was then employed to explore groundwater-flow dynamics in response to changes in pumping and recharge conditions. The simulation results indicate that pumping has a substantial effect on the confined aquifer flow regime as compared to the unconfined aquifer. The results and insights from this study have important implications for other regional groundwater modeling studies, especially in multi-layered aquifer systems.

  15. Future Flows Hydrology: an ensemble of daily river flow and monthly groundwater levels for use for climate change impact assessment across Great Britain

    Directory of Open Access Journals (Sweden)

    C. Prudhomme

    2012-12-01

    Full Text Available The dataset Future Flows Hydrology was developed as part of the project "Future Flows and Groundwater Levels" to provide a consistent set of transient daily river flow and monthly groundwater levels projections across England, Wales and Scotland to enable the investigation of the role of climate variability on river flow and groundwater levels nationally and how this may change in the future.

    Future Flows Hydrology is derived from Future Flows Climate, a national ensemble projection derived from the Hadley Centre's ensemble projection HadRM3-PPE to provide a consistent set of climate change projections for the whole of Great Britain at both space and time resolutions appropriate for hydrological applications. Three hydrological models and one groundwater level model were used to derive Future Flows Hydrology, with 30 river sites simulated by two hydrological models to enable assessment of hydrological modelling uncertainty in studying the impact of climate change on the hydrology.

    Future Flows Hydrology contains an 11-member ensemble of transient projections from January 1951 to December 2098, each associated with a single realisation from a different variant of HadRM3 and a single hydrological model. Daily river flows are provided for 281 river catchments and monthly groundwater levels at 24 boreholes as .csv files containing all 11 ensemble members. When separate simulations are done with two hydrological models, two separate .csv files are provided.

    Because of potential biases in the climate-hydrology modelling chain, catchment fact sheets are associated with each ensemble. These contain information on the uncertainty associated with the hydrological modelling when driven using observed climate and Future Flows Climate for a period representative of the reference time slice 1961–1990 as described by key hydrological statistics. Graphs of projected changes for selected hydrological indicators are also provided for

  16. Future Flows Hydrology: an ensemble of daily river flow and monthly groundwater levels for use for climate change impact assessment across Great Britain

    Directory of Open Access Journals (Sweden)

    C. Prudhomme

    2013-03-01

    Full Text Available The dataset Future Flows Hydrology was developed as part of the project "Future Flows and Groundwater Levels'' to provide a consistent set of transient daily river flow and monthly groundwater level projections across England, Wales and Scotland to enable the investigation of the role of climate variability on river flow and groundwater levels nationally and how this may change in the future. Future Flows Hydrology is derived from Future Flows Climate, a national ensemble projection derived from the Hadley Centre's ensemble projection HadRM3-PPE to provide a consistent set of climate change projections for the whole of Great Britain at both space and time resolutions appropriate for hydrological applications. Three hydrological models and one groundwater level model were used to derive Future Flows Hydrology, with 30 river sites simulated by two hydrological models to enable assessment of hydrological modelling uncertainty in studying the impact of climate change on the hydrology. Future Flows Hydrology contains an 11-member ensemble of transient projections from January 1951 to December 2098, each associated with a single realisation from a different variant of HadRM3 and a single hydrological model. Daily river flows are provided for 281 river catchments and monthly groundwater levels at 24 boreholes as .csv files containing all 11 ensemble members. When separate simulations are done with two hydrological models, two separate .csv files are provided. Because of potential biases in the climate–hydrology modelling chain, catchment fact sheets are associated with each ensemble. These contain information on the uncertainty associated with the hydrological modelling when driven using observed climate and Future Flows Climate for a period representative of the reference time slice 1961–1990 as described by key hydrological statistics. Graphs of projected changes for selected hydrological indicators are also provided for the 2050s time slice

  17. Derivation of Threshold Values for Groundwater in Romania, in order to distinguish Point & Diffuse pollution from natural background levels

    NARCIS (Netherlands)

    Schipper, P.N.M.; Radu, E.; Vliegenthart, F.; Balaet, R.

    2010-01-01

    Romania aims to adopt and implement the European Union's legislation, also including that for the field of water management. Like other countries, groundwater in Romania is locally polluted from point sources, such as leaking landfills, as well as from diffuse pollution sources, include fertilizers,

  18. Reduction of Cortisol Levels and Participants' Responses Following Art Making

    Science.gov (United States)

    Kaimal, Girija; Ray, Kendra; Muniz, Juan

    2016-01-01

    This quasi-experimental study investigated the impact of visual art making on the cortisol levels of 39 healthy adults. Participants provided saliva samples to assess cortisol levels before and after 45 minutes of art making. Participants also provided written responses about the experience at the end of the session. Results indicate that art…

  19. An Investigation of Relationships Among Question Level, Response Level and Lapse Time

    Science.gov (United States)

    Arnold, Daniel S.; And Others

    1973-01-01

    Studied relationships among questioning lapse time'' and the cognitive levels of teachers' questions and youngsters' responses, using Bloom's taxonomy and tape recordings in student teaching. Concluded that teachers' questions above the memory level could serve as a mechanism for promoting youngsters' learning at higher cognitive levels. (CC)

  20. Guidelines for selecting codes for ground-water transport modeling of low-level waste burial sites. Volume 2. Special test cases

    Energy Technology Data Exchange (ETDEWEB)

    Simmons, C.S.; Cole, C.R.

    1985-08-01

    This document was written for the National Low-Level Waste Management Program to provide guidance for managers and site operators who need to select ground-water transport codes for assessing shallow-land burial site performance. The guidance given in this report also serves the needs of applications-oriented users who work under the direction of a manager or site operator. The guidelines are published in two volumes designed to support the needs of users having different technical backgrounds. An executive summary, published separately, gives managers and site operators an overview of the main guideline report. Volume 1, titled ''Guideline Approach,'' consists of Chapters 1 through 5 and a glossary. Chapters 2 through 5 provide the more detailed discussions about the code selection approach. This volume, Volume 2, consists of four appendices reporting on the technical evaluation test cases designed to help verify the accuracy of ground-water transport codes. 20 refs.

  1. Groundwater regime and calculation of yield response in North China Plain: a case study of Luancheng County in Hebei Province

    Institute of Scientific and Technical Information of China (English)

    2002-01-01

    The groundwater table has been declining at a rate of 0.65 m/yr in Luancheng County since large scale groundwater extraction carried out in the 1960s. The drop of precipitation, substantial increase in agricultural output, variations of crop planting structure and construction of water conservancy projects in the headwater area all tie up with the decline of the groundwater table. On the basis of analyzing the hydrogeological conditions and the water resources utilization of Luancheng County, a three-dimensional groundwater flow model was developed to simulate the county's groundwater flow through finite-difference method using Visual Modflow software. We divide the research field into four parts after analyzing the hydrogeological condition. Based on parameter calibration and adjustment using measured data, the hydraulic conductivity and specific yield were simulated. Using the calibrated model, we analyze the agricultural water saving potentiality and its influence on the groundwater. The results are as follows: (1) if we decrease the amount of water extracted by 0.14× 108 m3, the average groundwater table of the five observation wells in December will rise by 0.33 m; (2) if we decrease the water by 0.29×10s m3, the average groundwater table of the five observation wells in December will rise by 0.64 m; and (3) if we increase the water by 0.29× 108 m3, the average groundwater table of the five observation wells in December will decline by 0.45 m. So we can draw a conclusion that controlling the agricultural water use is an important way to prevent the decline of groundwater table.

  2. Groundwater level monitoring sampling and analysis plan for environmental monitoring in Waste Area Grouping 6 at Oak Ridge National Laboratory, Oak Ridge, Tennessee

    Energy Technology Data Exchange (ETDEWEB)

    1994-04-01

    This Sampling and Analysis Plan addresses groundwater level monitoring activities that will be conducted in support of the Environmental Monitoring Plan for Waste Area Grouping (WAG) 6. WAG 6 is a shallow-burial land disposal facility for low-level radioactive waste at the Oak Ridge National Laboratory, a research facility owned by the US Department of Energy and managed by Martin Marietta Energy Systems, Inc. Groundwater level monitoring will be conducted at 129 sites within the WAG. All of the sites will be manually monitored on a semiannual basis. Forty-five of the 128 wells, plus one site in White Oak Lake, will also be equipped with automatic water level monitoring equipment. The 46 sites are divided into three groups. One group will be equipped for continuous monitoring of water level, conductivity, and temperature. The other two groups will be equipped for continuous monitoring of water level only. The equipment will be rotated between the two groups. The data collected from the water level monitoring will be used to support determination of the contaminant flux at WAG 6.

  3. 关中平原渠井双灌区地下水循环对环境变化的响应%Response of groundwater cycle to environmental changes in Guanzhong Plain irrigation district

    Institute of Scientific and Technical Information of China (English)

    李萍; 魏晓妹; 降亚楠; 冯东溥

    2014-01-01

    为促进陕西关中平原渠井双灌区地下水良性循环,保障灌区水资源高效安全利用,以泾惠渠灌区为例,分析了灌区多年来地下水系统外部环境因素及地下水循环要素的变化特征,基于多变量时间序列CAR(controlled auto-regressive)模型建立了地下水位动态对环境变化的响应模型,利用验证后的模型对灌区不同环境变化情景下的地下水位埋深进行了模拟。研究结果表明:降水、蒸发、渠首引水、渠井用水比例是影响灌区地下水循环的主要外部环境因素;降水量减少、蒸发量增加,地下水各项补给量减少、排泄量增加,使得地下水位逐年下降,近34 a累计下降11.8 m;在多年平均降水量情景Ⅰ下(近56 a均值:513 mm),维持灌区地下水良性循环的适宜渠井用水比例为1.53,在多年平均降水量减少5%,即降水情景Ⅱ下(487 mm),适宜渠井用水比例为1.61。环境变化下不同渠井用水方案的研究,有利于灌区地下水的良性循环,可为灌区制定高效安全用水对策提供依据。%Healthy groundwater cycle can ensure that water resources are used more efficiently and securely in northern irrigation district. In recent years, groundwater cycle condition in the irrigation district affected by climate change and human activities has changed greatly. Environmental problems such as the attenuation of groundwater storage capacity, hanging pump wells and the groundwater deterioration occur with the unhealthy groundwater cycle in some northern areas, which directly affect the safety and efficiency of water resource utilization in the irrigation district. Therefore, studies on response of groundwater cycle to environmental changes in the irrigation district are urgent and important. This study took Jinghui Canal Irrigation District in Shaanxi province as a research area, analyzed variations of characteristics of external environment

  4. The European 2015 drought from a groundwater perspective

    Science.gov (United States)

    Van Loon, Anne; Kumar, Rohini; Mishra, Vimal

    2017-04-01

    In 2015 central and eastern Europe were affected by severe drought. Impacts of the drought were felt across many sectors, incl. agriculture, drinking water supply, electricity production, navigation, fisheries, and recreation. This drought event has recently been studied from meteorological and streamflow perspective, but no analysis of the groundwater drought has been performed. This is not surprising because real-time groundwater level observations often are not available. In this study we use previously established spatially-explicit relationships between meteorological drought and groundwater drought to quantify the 2015 groundwater drought over two regions in southern Germany and eastern Netherlands. We also tested the applicability of the Gravity Recovery Climate Experiment (GRACE) Terrestrial Water Storage (TWS) and GRACE-based groundwater anomalies to capture the spatial variability of the 2003 and 2015 drought events. We use the monthly groundwater observations from 2040 wells to establish the spatially varying optimal accumulation period between the Standardized Groundwater Index (SGI) and the Standardized Precipitation Evapotranspiration Index (SPEI) at a 0.250 gridded scale. The resulting optimal accumulation periods range between 1 and more than 24 months, indicating strong spatial differences in groundwater response time to meteorological input over the region. Based on these optimal accumulation periods, we found that in Germany a uniform severe groundwater drought persisted for several months (i.e. SGI below the drought threshold of 20th percentile for almost all grid cells in August, September and October 2015), whereas the Netherlands appeared to have relatively high groundwater levels (never below the drought threshold of 20th percentile). The differences between this event and the European 2003 benchmark drought are striking. The 2003 groundwater drought was less uniformly pronounced, both in the Netherlands and Germany, with the regional

  5. Estimation of spatial distrubition of groundwater level and risky areas of seawater intrusion on the coastal region in Çarşamba Plain, Turkey, using different interpolation methods.

    Science.gov (United States)

    Arslan, Hakan

    2014-08-01

    Groundwater level plays a significant role in coastal plains. Heavy pumping and excessive use of near-coast groundwater can increase the intrusion of seawater into the aquifers. In the present study, groundwater levels were measured at 59 groundwater wells at different times during pre- and post-irrigation seasons (April and September of the year 2012) in Çarşamba Plain, Turkey. To select the best method, two deterministic interpolation methods (inverse distance weighing (IDW) with the weights of 1, 2, and 3 and radial basis function (RBF) with spline with tension (SPT) and completely regularized spline (CRS)) and two stochastic methods (ordinary kriging (OK) with spherical, exponential, and Gaussian variograms) and cokriging (COK)) were compared and then the best interpolation method was used to evaluate the spatial distribution of groundwater levels in different seasons and seasonal changes. A total of nine different techniques were tested. Also, risky areas of seawater intrusion in coastal area were determined using the best methods for two periods. The performance of these interpolation methods is evaluated by using a validation test method. Statistical indices of correlation (R (2)), mean absolute error (MAE), and root-mean-square error (RMSE) were used to select and validate the best methods. Comparisons between predicted and observed values indicated RBF as the optimal method for groundwater level estimation in April and September. When the best method RBF and the worst method IDW were compared, significant differences were observed in the spatial distribution of groundwater. Results of the study also revealed that excessive groundwater withdrawals during the post-irrigation season dropped the groundwater levels up to 2.0 m in some sections. With regard to seawater intrusion, 9,103 ha of land area was determined to be highly risky and risky.

  6. High-resolution monitoring across the soil-groundwater interface - Revealing small-scale hydrochemical patterns with a novel multi-level well

    Science.gov (United States)

    Gassen, Niklas; Griebler, Christian; Stumpp, Christine

    2016-04-01

    Biogeochemical turnover processes in the subsurface are highly variable both in time and space. In order to capture this variability, high resolution monitoring systems are required. Particular in riparian zones the understanding of small-scale biogeochemical processes is of interest, as they are regarded as important buffer zones for nutrients and contaminants with high turnover rates. To date, riparian research has focused on influences of groundwater-surface water interactions on element cycling, but little is known about processes occurring at the interface between the saturated and the unsaturated zone during dynamic flow conditions. Therefore, we developed a new type of high resolution multi-level well (HR-MLW) that has been installed in the riparian zone of the Selke river. This HR-MLW for the first time enables to derive water samples both from the unsaturated and the saturated zone across one vertical profile with a spatial vertical resolution of 0.05 to 0.5 m to a depth of 4 m b.l.s. Water samples from the unsaturated zone are extracted via suction cup sampling. Samples from the saturated zone are withdrawn through glass filters and steel capillaries. Both, ceramic cups and glass filters, are installed along a 1" HDPE piezometer tube. First high resolution hydrochemical profiles revealed a distinct depth-zonation in the riparian alluvial aquifer. A shallow zone beneath the water table carried a signature isotopically and hydrochemically similar to the nearby river, while layers below 1.5 m were influenced by regional groundwater. This zonation showed temporal dynamics related to groundwater table fluctuations and microbial turnover processes. The HR-MLW delivered new insight into mixing and turnover processes between riverwater and groundwater in riparian zones, both in a temporal and spatial dimension. With these new insights, we are able to improve our understanding of dynamic turnover processes at the soil - groundwater interface and of surface

  7. Responses of fen plant species to groundwater level and light intensity

    NARCIS (Netherlands)

    Kotowski, W; van Andel, J; van Diggelen, R; Hogendorf, J.

    Characteristic species of sedge-moss fen communities occur in constantly wet, nutrient-poor sites with a high penetration of light through the vegetation canopy. We studied the effects of water table depth and differences in light intensity on the performance of fen species. Three fen species (Carex

  8. Physical, chemical, and mineralogical data from surficial deposits, groundwater levels, and water composition in the area of Franklin Lake playa and Ash Meadows, California and Nevada

    Science.gov (United States)

    Goldstein, Harland L.; Breit, George N.; Yount, James C.; Reynolds, Richard L.; Reheis, Marith C.; Skipp, Gary L.; Fisher, Eric M.; Lamothe, Paul J.

    2011-01-01

    This report presents data and describes the methods used to determine the physical attributes, as well as the chemical and mineralogical composition of surficial deposits; groundwater levels; and water composition in the area of Franklin Lake playa and Ash Meadows, California and Nevada. The results support studies that examine (1) the interaction between groundwater and the ground surface, and the transport of solutes through the unsaturated zone; (2) the potential for the accumulation of metals and metalloids in surface crusts; (3) emission of dust from metal-rich salt crust; and (4) the effects of metal-rich dusts on human and ecosystem health. The evaporation of shallow (salt in the subsurface and (or) the formation of salt crusts at the ground surface. Ground-surface characteristics such as hardness, electrical conductivity, and mineralogy depend on the types and forms of these salt crusts. In the study area, salt crusts range from hard and bedded to soft and loose (Reynolds and others, 2009). Depending on various factors such as the depth and composition of groundwater and sediment characteristics of the unsaturated zone, salt crusts may accumulate relatively high contents of trace elements. Soft, loose salt crusts are highly vulnerable to wind erosion and transport. These vulnerable crusts, which may contain high contents of potentially toxic trace elements, can travel as atmospheric dust and affect human and ecosystem health at local to regional scales.

  9. Groundwater simulation and management models for the upper Klamath Basin, Oregon and California

    Science.gov (United States)

    Gannett, Marshall W.; Wagner, Brian J.; Lite, Kenneth E.

    2012-01-01

    The upper Klamath Basin encompasses about 8,000 square miles, extending from the Cascade Range east to the Basin and Range geologic province in south-central Oregon and northern California. The geography of the basin is dominated by forested volcanic uplands separated by broad interior basins. Most of the interior basins once held broad shallow lakes and extensive wetlands, but most of these areas have been drained or otherwise modified and are now cultivated. Major parts of the interior basins are managed as wildlife refuges, primarily for migratory waterfowl. The permeable volcanic bedrock of the upper Klamath Basin hosts a substantial regional groundwater system that provides much of the flow to major streams and lakes that, in turn, provide water for wildlife habitat and are the principal source of irrigation water for the basin's agricultural economy. Increased allocation of surface water for endangered species in the past decade has resulted in increased groundwater pumping and growing interest in the use of groundwater for irrigation. The potential effects of increased groundwater pumping on groundwater levels and discharge to springs and streams has caused concern among groundwater users, wildlife and Tribal interests, and State and Federal resource managers. To provide information on the potential impacts of increased groundwater development and to aid in the development of a groundwater management strategy, the U.S. Geological Survey, in collaboration with the Oregon Water Resources Department and the Bureau of Reclamation, has developed a groundwater model that can simulate the response of the hydrologic system to these new stresses. The groundwater model was developed using the U.S. Geological Survey MODFLOW finite-difference modeling code and calibrated using inverse methods to transient conditions from 1989 through 2004 with quarterly stress periods. Groundwater recharge and agricultural and municipal pumping are specified for each stress period. All

  10. Groundwater data network interoperability

    Science.gov (United States)

    Brodaric, Boyan; Booth, Nathaniel; Boisvert, Eric; Lucido, Jessica M.

    2016-01-01

    Water data networks are increasingly being integrated to answer complex scientific questions that often span large geographical areas and cross political borders. Data heterogeneity is a major obstacle that impedes interoperability within and between such networks. It is resolved here for groundwater data at five levels of interoperability, within a Spatial Data Infrastructure architecture. The result is a pair of distinct national groundwater data networks for the United States and Canada, and a combined data network in which they are interoperable. This combined data network enables, for the first time, transparent public access to harmonized groundwater data from both sides of the shared international border.

  11. Groundwater dynamics mediate low-flow response to global warming in snow-dominated alpine regions

    Science.gov (United States)

    Christina Tague; Gordon E. Grant

    2009-01-01

    In mountain environments, spatial and temporal patterns of snow accumulation and melt are dominant controls on hydrologic responses to climate change. In this paper, we develop a simple conceptual model that links the timing of peak snowmelt with geologically mediated differences in rate of streamflow recession. This model demonstrates that within the western United...

  12. Barrier response to Holocene sea-level rise

    DEFF Research Database (Denmark)

    Pejrup, Morten; Andersen, Thorbjørn Joest; Johannessen, Peter N

    Normally it is believed that sea-level rise causes coastal barrier retreat. However, sea-level is only one of the parameters determining the long term coastal development of barrier coasts. Sediment supply is an equally important determinant and may overshadow the effects of sea-level rise...... show quite different responses to sea-level rise. The southernmost island Rømø has survived 17 m of sea-level rise at the same position illustrating the control from sediment supply; whereas the northernmost island Skallingen has shifted its position several times during the same period indicating...... a much stronger component of sea-level control. The distance between the islands is only 50 km, and therefore our study shows that prediction of barrier development during a period of rising sea level may be more complicated than formerly believed....

  13. Effect of diversified crop rotations on groundwater levels and crop water productivity in the North China Plain

    Science.gov (United States)

    Yang, Xiaolin; Chen, Yuanquan; Pacenka, Steven; Gao, Wangsheng; Ma, Li; Wang, Guangya; Yan, Peng; Sui, Peng; Steenhuis, Tammo S.

    2015-03-01

    Water shortage is the major bottleneck that limits sustainable yield of agriculture in the North China Plain. Due to the over-exploitation of groundwater for irrigating the winter wheat-summer maize double cropping systems, a groundwater crisis is becoming increasingly serious. To help identify more efficient and sustainable utilization of the limited water resources, the water consumption and water use efficiency of five irrigated cropping systems were calculated and the effect of cropping systems on groundwater table changes was estimated based on a long term field experiment from 2003 to 2013 in the North China Plain interpreted using a soil-water-balance model. The five cropping systems included sweet potato → cotton → sweet potato → winter wheat-summer maize (SpCSpWS, 4-year cycle), ryegrass-cotton → peanuts → winter wheat-summer maize (RCPWS, 3-year cycle), peanuts → winter wheat-summer maize (PWS, 2-year cycle), winter wheat-summer maize (WS, 1-year cycle), and continuous cotton (Cont C). The five cropping systems had a wide range of annual average actual evapotranspiration (ETa): Cont C (533 mm/year) RCPWS (0.7 m/year) > PWS (0.6 m/year) > SPCSPWS and Cont C (0.4 m/year). The annual average economic output water use efficiency (WUEe) increased in the order SpCSpWS (11.6 yuan ¥ m-3) > RCPWS (9.0 ¥ m-3) > PWS (7.3 ¥ m-3) > WS (6.8 ¥ m-3) > Cont C (5.6 ¥ m-3) from 2003 to 2013. Results strongly suggest that diversifying crop rotations could play a critically important role in mitigating the over-exploitation of the groundwater, while ensuring the food security or boosting the income of farmers in the North China Plain.

  14. Modeling of Morelia Fault Earthquake (Mw=5.4) source fault parameters using the coseismic ground deformation and groundwater level changes data

    Science.gov (United States)

    Sarychikhina, O.; Glowacka, E.; Mellors, R. J.; Vázquez, R.

    2009-12-01

    On 24 May 2006 at 04:20 (UTC) a moderate-size (Mw=5.4) earthquake struck the Mexicali Valley, Baja California, México, roughly 30 km to the southeast of the city of Mexicali, in the vicinity of the Cerro Prieto Geothermal Field (CPGF). The earthquake occurred on the Morelia fault, one of the east-dipping normal faults in the Mexicali Valley. Locally, this earthquake was strongly felt and caused minor damage. The event created 5 km of surface rupture and down-dip displacements of up to 25-30 cm were measured at some places along this surface rupture. Associated deformation was measured by vertical crackmeter, leveling profile, and Differential Synthetic Aperture Radar Interferometry (D-InSAR). A coseismic step-like groundwater level change was detected at 7 wells. The Mw=5.4 Morelia Fault earthquake had significant scientific interest, first, because of surprisingly strong effects for an earthquake of such size; second, the variability of coseismic effects data from different ground-based and space-based techniques which allows to the better constrain of the source fault parameters. Source parameters for the earthquake were estimated using forward modeling of both surface deformation data and static volume strain change (inferred from coseismic changes in groundwater level). All ground deformation data was corrected by anthropogenic component caused by the geothermal fluid exploitation in the CPGF. Modeling was based on finite rectangular fault embedded in an elastic media. The preferred fault model has a strike, rake, and dip of (48°, -89°, 45°) and has a length of 5.2 km, width of 6.7 km, and 34 cm of uniform slip. The geodetic moment, based on the modeled fault parameters, is 1.18E+17 Nm. The model matches the observed surface deformation, expected groundwater level changes, and teleseismic moment reasonably well and explains in part why the earthquake was so strongly felt in the area.

  15. Cell cycle progression in response to oxygen levels.

    Science.gov (United States)

    Ortmann, Brian; Druker, Jimena; Rocha, Sonia

    2014-09-01

    Hypoxia' or decreases in oxygen availability' results in the activation of a number of different responses at both the whole organism and the cellular level. These responses include drastic changes in gene expression, which allow the organism (or cell) to cope efficiently with the stresses associated with the hypoxic insult. A major breakthrough in the understanding of the cellular response to hypoxia was the discovery of a hypoxia sensitive family of transcription factors known as the hypoxia inducible factors (HIFs). The hypoxia response mounted by the HIFs promotes cell survival and energy conservation. As such, this response has to deal with important cellular process such as cell division. In this review, the integration of oxygen sensing with the cell cycle will be discussed. HIFs, as well as other components of the hypoxia pathway, can influence cell cycle progression. The role of HIF and the cell molecular oxygen sensors in the control of the cell cycle will be reviewed.

  16. Groundwater availability of the Mississippi embayment

    Science.gov (United States)

    Clark, Brian R.; Hart, Rheannon M.; Gurdak, Jason J.

    2011-01-01

    Groundwater is an important resource for agricultural and municipal uses in the Mississippi embayment. Arkansas ranks first in the Nation for rice and third for cotton production, with both crops dependent on groundwater as a major source of irrigation requirements. Multiple municipalities rely on the groundwater resources to provide water for industrial and public use, which includes the city of Memphis, Tennessee. The demand for the groundwater resource has resulted in groundwater availability issues in the Mississippi embayment including: (1) declining groundwater levels of 50 feet or more in the Mississippi River Valley alluvial aquifer in parts of eastern Arkansas from agricultural pumping, (2) declining groundwater levels of over 360 feet over the last 90 years in the confined middle Claiborne aquifer in southern Arkansas and northern Louisiana from municipal pumping, and (3) litigation between the State of Mississippi and a Memphis water utility over water rights in the middle Claiborne aquifer. To provide information to stakeholders addressing the groundwater-availability issues, the U.S. Geological Survey Groundwater Resources Program supported a detailed assessment of groundwater availability through the Mississippi Embayment Regional Aquifer Study (MERAS). This assessment included (1) an evaluation of how these resources have changed over time through the use of groundwater budgets, (2) development of a numerical modeling tool to assess system responses to stresses from future human uses and climate trends, and (3) application of statistical tools to evaluate the importance of individual observations within a groundwater-monitoring network. An estimated 12 million acre-feet per year (11 billion gallons per day) of groundwater was pumped in 2005 from aquifers in the Mississippi embayment. Irrigation constitutes the largest groundwater use, accounting for approximately 10 million acre-feet per year (9 billion gallons per day) in 2000 from the Mississippi

  17. Confidence sets for optimal factor levels of a response surface.

    Science.gov (United States)

    Wan, Fang; Liu, Wei; Bretz, Frank; Han, Yang

    2016-12-01

    Construction of confidence sets for the optimal factor levels is an important topic in response surfaces methodology. In Wan et al. (2015), an exact (1-α) confidence set has been provided for a maximum or minimum point (i.e., an optimal factor level) of a univariate polynomial function in a given interval. In this article, the method has been extended to construct an exact (1-α) confidence set for the optimal factor levels of response surfaces. The construction method is readily applied to many parametric and semiparametric regression models involving a quadratic function. A conservative confidence set has been provided as an intermediate step in the construction of the exact confidence set. Two examples are given to illustrate the application of the confidence sets. The comparison between confidence sets indicates that our exact confidence set is better than the only other confidence set available in the statistical literature that guarantees the (1-α) confidence level. © 2016, The International Biometric Society.

  18. Analyses of infrequent (quasi-decadal) large groundwater recharge events in the northern Great Basin: Their importance for groundwater availability, use, and management

    Science.gov (United States)

    Masbruch, Melissa D.; Rumsey, Christine; Gangopadhyay, Subhrendu; Susong, David D.; Pruitt, Tom

    2016-01-01

    There has been a considerable amount of research linking climatic variability to hydrologic responses in the western United States. Although much effort has been spent to assess and predict changes in surface water resources, little has been done to understand how climatic events and changes affect groundwater resources. This study focuses on characterizing and quantifying the effects of large, multiyear, quasi-decadal groundwater recharge events in the northern Utah portion of the Great Basin for the period 1960–2013. Annual groundwater level data were analyzed with climatic data to characterize climatic conditions and frequency of these large recharge events. Using observed water-level changes and multivariate analysis, five large groundwater recharge events were identified with a frequency of about 11–13 years. These events were generally characterized as having above-average annual precipitation and snow water equivalent and below-average seasonal temperatures, especially during the spring (April through June). Existing groundwater flow models for several basins within the study area were used to quantify changes in groundwater storage from these events. Simulated groundwater storage increases per basin from a single recharge event ranged from about 115 to 205 Mm3. Extrapolating these amounts over the entire northern Great Basin indicates that a single large quasi-decadal recharge event could result in billions of cubic meters of groundwater storage. Understanding the role of these large quasi-decadal recharge events in replenishing aquifers and sustaining water supplies is crucial for long-term groundwater management.

  19. Analyses of infrequent (quasi-decadal) large groundwater recharge events in the northern Great Basin: Their importance for groundwater availability, use, and management

    Science.gov (United States)

    Gangopadhyay, Subhrendu; Masbruch, Melissa D.; Pruitt, Tom; Rumsey, Christine; Susong, David D.

    2016-01-01

    There has been a considerable amount of research linking climatic variability to hydrologic responses in the western United States. Although much effort has been spent to assess and predict changes in surface water resources, little has been done to understand how climatic events and changes affect groundwater resources. This study focuses on characterizing and quantifying the effects of large, multiyear, quasi-decadal groundwater recharge events in the northern Utah portion of the Great Basin for the period 1960–2013. Annual groundwater level data were analyzed with climatic data to characterize climatic conditions and frequency of these large recharge events. Using observed water-level changes and multivariate analysis, five large groundwater recharge events were identified with a frequency of about 11–13 years. These events were generally characterized as having above-average annual precipitation and snow water equivalent and below-average seasonal temperatures, especially during the spring (April through June). Existing groundwater flow models for several basins within the study area were used to quantify changes in groundwater storage from these events. Simulated groundwater storage increases per basin from a single recharge event ranged from about 115 to 205 million cubic meters. Extrapolating these amounts over the entire northern Great Basin indicates that a single large quasi-decadal recharge event could result in billions of cubic meters of groundwater storage. Understanding the role of these large quasi-decadal recharge events in replenishing aquifers and sustaining water supplies is crucial for long-term groundwater management.

  20. Analyses of infrequent (quasi-decadal) large groundwater recharge events in the northern Great Basin: Their importance for groundwater availability, use, and management

    Science.gov (United States)

    Masbruch, Melissa D.; Rumsey, Christine A.; Gangopadhyay, Subhrendu; Susong, David D.; Pruitt, Tom

    2016-10-01

    There has been a considerable amount of research linking climatic variability to hydrologic responses in the western United States. Although much effort has been spent to assess and predict changes in surface water resources, little has been done to understand how climatic events and changes affect groundwater resources. This study focuses on characterizing and quantifying the effects of large, multiyear, quasi-decadal groundwater recharge events in the northern Utah portion of the Great Basin for the period 1960-2013. Annual groundwater level data were analyzed with climatic data to characterize climatic conditions and frequency of these large recharge events. Using observed water-level changes and multivariate analysis, five large groundwater recharge events were identified with a frequency of about 11-13 years. These events were generally characterized as having above-average annual precipitation and snow water equivalent and below-average seasonal temperatures, especially during the spring (April through June). Existing groundwater flow models for several basins within the study area were used to quantify changes in groundwater storage from these events. Simulated groundwater storage increases per basin from a single recharge event ranged from about 115 to 205 Mm3. Extrapolating these amounts over the entire northern Great Basin indicates that a single large quasi-decadal recharge event could result in billions of cubic meters of groundwater storage. Understanding the role of these large quasi-decadal recharge events in replenishing aquifers and sustaining water supplies is crucial for long-term groundwater management.

  1. Hydrologic response to multimodel climate output using a physically based model of groundwater/surface water interactions

    Science.gov (United States)

    Sulis, M.; Paniconi, C.; Marrocu, M.; Huard, D.; Chaumont, D.

    2012-12-01

    General circulation models (GCMs) are the primary instruments for obtaining projections of future global climate change. Outputs from GCMs, aided by dynamical and/or statistical downscaling techniques, have long been used to simulate changes in regional climate systems over wide spatiotemporal scales. Numerous studies have acknowledged the disagreements between the various GCMs and between the different downscaling methods designed to compensate for the mismatch between climate model output and the spatial scale at which hydrological models are applied. Very little is known, however, about the importance of these differences once they have been input or assimilated by a nonlinear hydrological model. This issue is investigated here at the catchment scale using a process-based model of integrated surface and subsurface hydrologic response driven by outputs from 12 members of a multimodel climate ensemble. The data set consists of daily values of precipitation and min/max temperatures obtained by combining four regional climate models and five GCMs. The regional scenarios were downscaled using a quantile scaling bias-correction technique. The hydrologic response was simulated for the 690 km2des Anglais catchment in southwestern Quebec, Canada. The results show that different hydrological components (river discharge, aquifer recharge, and soil moisture storage) respond differently to precipitation and temperature anomalies in the multimodel climate output, with greater variability for annual discharge compared to recharge and soil moisture storage. We also find that runoff generation and extreme event-driven peak hydrograph flows are highly sensitive to any uncertainty in climate data. Finally, the results show the significant impact of changing sequences of rainy days on groundwater recharge fluxes and the influence of longer dry spells in modifying soil moisture spatial variability.

  2. Conjunctive management of multi-reservoir network system and groundwater system

    Science.gov (United States)

    Mani, A.; Tsai, F. T. C.

    2015-12-01

    This study develops a successive mixed-integer linear fractional programming (successive MILFP) method to conjunctively manage water resources provided by a multi-reservoir network system and a groundwater system. The conjunctive management objectives are to maximize groundwater withdrawals and maximize reservoir storages while satisfying water demands and raising groundwater level to a target level. The decision variables in the management problem are reservoir releases and spills, network flows and groundwater pumping rates. Using the fractional programming approach, the objective function is defined as a ratio of total groundwater withdraws to total reservoir storage deficits from the maximum storages. Maximizing this ratio function tends to maximizing groundwater use and minimizing surface water use. This study introduces a conditional constraint on groundwater head in order to sustain aquifers from overpumping: if current groundwater level is less than a target level, groundwater head at the next time period has to be raised; otherwise, it is allowed to decrease up to a certain extent. This conditional constraint is formulated into a set of mixed binary nonlinear constraints and results in a mixed-integer nonlinear fractional programming (MINLFP) problem. To solve the MINLFP problem, we first use the response matrix approach to linearize groundwater head with respect to pumping rate and reduce the problem to an MILFP problem. Using the Charnes-Cooper transformation, the MILFP is transformed to an equivalent mixed-integer linear programming (MILP). The solution of the MILP is successively updated by updating the response matrix in every iteration. The study uses IBM CPLEX to solve the MILP problem. The methodology is applied to water resources management in northern Louisiana. This conjunctive management approach aims to recover the declining groundwater level of the stressed Sparta aquifer by using surface water from a network of four reservoirs as an

  3. Sustainability of groundwater supplies in the Northern Atlantic Coastal Plain aquifer system

    Science.gov (United States)

    Masterson, John P.; Pope, Jason P.

    2016-08-31

    Groundwater is the Nation’s principal reserve of freshwater. It provides about half our drinking water, is essential to food production, and facilitates business and industry in developing economic well-being. Groundwater is also an important source of water for sustaining the ecosystem health of rivers, wetlands, and estuaries throughout the country. The decreases in groundwater levels and other effects of pumping that result from large-scale development of groundwater resources have led to concerns about the future availability of groundwater to meet all our Nation’s needs. Assessments of groundwater availability provide the science and information needed by the public and decision makers to manage water resources and use them responsibly.

  4. Shallow groundwater nitrogen responses to different land use managements in the riparian zone of Yuqiao Reservoir in North China

    Institute of Scientific and Technical Information of China (English)

    LU Haiming; YIN Chengqing

    2008-01-01

    This field study investigated the nitrogen concentrations in the shallow groundwater from an ephemeral stream and four land uses:cropland,two-year restored (2yr) and five-years restored (5yr) woodlands,fishponds,and the nitrogen flux in the riparian zone of Yuqiao Reservoir.The groundwater nitrate-N concentrations in cropland were the highest among the four land uses.Total dissolved nitrogen (TDN) and nitrate-N concentrations in the 2yr woodland were significantly (p<0.05) higher than in 5yr woodland.The lowest nitrogen concentrations were detected in fishponds.Nitrate-N was the main form in cropland and 2yr woodland,whereas both nitrate-N and diSSolved organic nitrogen (DON) were the main species in 5yr woodland and fishponds.But,ammonium-N was the main form in the ephemeral stream.During the rainy season,the groundwater flow wim dissolved nitrogen drains from upland into the reservoir along the hydraulic gradient.The woodland between the cropland and reservoir could act as a buffer to retain shallow groundwater nitrogen.The dominant form of ammonium-N in the groundwater TDN pool in ephemeral stream indicated that nitrogen from the village and orchard in upland flowed into the reservoir via subsurface flow.The fishpond Was not an important pollution source for nitrogen transfer via shallow groundwater.

  5. Evaluation of levels of antibiotic resistance in groundwater-derived E. coli isolates in the Midwest of Ireland and elucidation of potential predictors of resistance

    Science.gov (United States)

    O'Dwyer, Jean; Hynds, Paul; Pot, Matthieu; Adley, Catherine C.; Ryan, Michael P.

    2017-02-01

    Antibiotic-resistant (pathogenic and non-pathogenic) organisms and genes are now acknowledged as significant emerging aquatic contaminants with potentially adverse human and ecological health impacts, and thus require monitoring. This study is the first to investigate levels of resistance among Irish groundwater (private wells) samples; Escherichia coli isolates were examined against a panel of commonly prescribed human and veterinary therapeutic antibiotics, followed by determination of the causative factors of resistance. Overall, 42 confirmed E. coli isolates were recovered from a groundwater-sampling cohort. Resistance to the human panel of antibiotics was moderate; nine (21.4%) E. coli isolates demonstrated resistance to one or more human antibiotics. Conversely, extremely high levels of resistance to veterinary antibiotics were found, with all isolates presenting resistance to one or more veterinary antibiotics. Particularly high levels of resistance (93%) were found with respect to the aminoglycoside class of antibiotics. Results of statistical analysis indicate a significant association between the presence of human (multiple) antibiotic resistance (p = 0.002-0.011) and both septic tank density and the presence of vulnerable sub-populations (<5 years). For the veterinary antibiotics, results point to a significant relationship (p = <0.001) between livestock (cattle) density and the prevalence of multiple antibiotic resistant E. coli. Groundwater continues to be an important resource in Ireland, particularly in rural areas; thus, results of this preliminary study offer a valuable insight into the prevalence of antibiotic resistance in the hydrogeological environment and establish a need for further research with a larger geological diversity.

  6. Investigation of groundwater behavior in response to oceanic tide and hydrodynamic assessment of coastal aquifers.

    Science.gov (United States)

    Fadili, Ahmed; Malaurent, Philippe; Najib, Saliha; Mehdi, Khalid; Riss, Joëlle; Makan, Abdelhadi; Boutayeb, Khadija

    2016-05-01

    This study was based, firstly, on observations and analysis of water table level variations in the Plio-Quaternary and Hauterivian aquifers, Oualidia (Morocco), and secondly, on comparing this behavior to oceanic tidal variations. Recordings were made in the well located at 1318 m from the coast, where the two aquifers are in direct contact. This investigation was subdivided into two periods of 4 months each. Results showed a tidal influence on water table level within the well during semi-diurnal and monthly periods. Water table fluctuation periods were equal to 12 h 25 min identical to oceanic tide propagation period, while time lag between water levels was equal to 3 h 24 min. Moreover, results allowed aquifer diffusivity calculation through a confined aquifer model, which was equal to 6.20 m(2) s(-1) calculated from average value of water amplitude and to 40.6 m(2) s(-1) calculated from average value of time lag. In addition, tidal wave amplitude attenuation occurred exponentially with distance from ocean, which disappeared completely after 2000 m from coast.

  7. Updated study reporting levels (SRLs) for trace-element data collected for the California Groundwater Ambient Monitoring and Assessment (GAMA) Priority Basin Project, October 2009-March 2013

    Science.gov (United States)

    Davis, Tracy A.; Olsen, Lisa D.; Fram, Miranda S.; Belitz, Kenneth

    2014-01-01

    Groundwater samples have been collected in California as part of statewide investigations of groundwater quality conducted by the U.S. Geological Survey for the Groundwater Ambient Monitoring and Assessment (GAMA) Priority Basin Project (PBP). The GAMA-PBP is being conducted in cooperation with the California State Water Resources Control Board to assess and monitor the quality of groundwater resources used for drinking-water supply and to improve public knowledge of groundwater quality in California. Quality-control samples (source-solution blanks, equipment blanks, and field blanks) were collected in order to ensure the quality of the groundwater sample results. Olsen and others (2010) previously determined study reporting levels (SRLs) for trace-element results based primarily on field blanks collected in California from May 2004 through January 2008. SRLs are raised reporting levels used to reduce the likelihood of reporting false detections attributable to contamination bias. The purpose of this report is to identify any changes in the frequency and concentrations of detections in field blanks since the last evaluation and update the SRLs for more recent data accordingly. Constituents analyzed were aluminum (Al), antimony (Sb), arsenic (As), barium (Ba), beryllium (Be), boron (B), cadmium (Cd), chromium (Cr), cobalt (Co), copper (Cu), iron (Fe), lead (Pb), lithium (Li), manganese (Mn), molybdenum (Mo), nickel (Ni), selenium (Se), silver (Ag), strontium (Sr), thallium (Tl), tungsten (W), uranium (U), vanadium (V), and zinc (Zn). Data from 179 field blanks and equipment blanks collected from March 2006 through March 2013 by the GAMA-PBP indicated that for trace elements that had a change in detection frequency and concentration since the previous review, the shift occurred near October 2009, in conjunction with a change in the capsule filters used by the study. Results for 89 field blanks and equipment blanks collected from October 2009 through March 2013 were

  8. Research on the Technology of Extracting Earthquake Precursor Information from Groundwater Level%地下水位中地震前兆信息提取方法研究

    Institute of Scientific and Technical Information of China (English)

    赵栋; 易立新; 王广才; 张玺

    2013-01-01

    all of the components.Changes caused by Earth tide and atmospheric pressure were first separated according to the BAYTAP-G procedure.Then,because quick and slow response existed in the influence of rainfall on groundwater level,these effects were distinguished by applying base flow separation methods.Changes induced by rainfall were separated from groundwater level by using base flow separation methods.By analyzing the relationships between the curve feature of every component and local seismic activities,local earthquake precursor information on groundwater level could be recognized.In this study,we selected as research objects two observation wells including the Deyang Well in Sichuan,one of China's earthquake undc-ground fluid observation networks,the and Tuanjie-1 Well,one of the earthquake underground fluid dynamic monitoring networks located downstream of the Jinshajiang River.Based on the data of underground water level and pressure from the Deyang Well from April 1 to June 30,2008,we analyzed the changes in curves before and after the M8.0 Wenchuan earthquake that occurred on May 12,2008.On the basis of synchronous observation data of underground water level,rainfall,and pressure of the Tuanjie-1 Well from December 1,2010,to December 31,2011,we analyzed the effects of rainfall on water level.Results show that methods that regarded the underground water level as a linear combination of various factors and separated types of effect value from the original data were effective in practice.In addition,base flow separation methods were effective in reducing peaks of the rainfall influence on underground water level.Thus,earthquake precursor information can be identified more effectively.Once significant change occurs,whether such change is induced by earthquake activities needs to be considered.Through systematic research of a large number of typical earthquake examples,a regional earthquake precursor change model can be created,which can be used for earthquake

  9. Tracing groundwater with low-level detections of halogenated VOCs in a fractured carbonate-rock aquifer, Leetown Science Center, West Virginia, USA

    Science.gov (United States)

    Plummer, L. Niel; Sibrell, Philip L.; Casile, Gerolamo C.; Busenberg, Eurybiades; Hunt, Andrew G.; Schlosser, Peter

    2013-01-01

    Measurements of low-level concentrations of halogenated volatile organic compounds (VOCs) and estimates of groundwater age interpreted from 3H/3He and SF6 data have led to an improved understanding of groundwater flow, water sources, and transit times in a karstic, fractured, carbonate-rock aquifer at the Leetown Science Center (LSC), West Virginia. The sum of the concentrations of a set of 16 predominant halogenated VOCs (TDVOC) determined by gas chromatography with electron-capture detector (GC–ECD) exceeded that possible for air–water equilibrium in 34 of the 47 samples (median TDVOC of 24,800 pg kg−1), indicating that nearly all the water sampled in the vicinity of the LSC has been affected by addition of halogenated VOCs from non-atmospheric source(s). Leakage from a landfill that was closed and sealed nearly 20 a prior to sampling was recognized and traced to areas east of the LSC using low-level detection of tetrachloroethene (PCE), methyl chloride (MeCl), methyl chloroform (MC), dichlorodifluoromethane (CFC-12), and cis-1,2-dichloroethene (cis-1,2-DCE). Chloroform (CHLF) was the predominant VOC in water from domestic wells surrounding the LSC, and was elevated in groundwater in and near the Fish Health Laboratory at the LSC, where a leak of chlorinated water occurred prior to 2006. The low-level concentrations of halogenated VOCs did not exceed human or aquatic-life health criteria, and were useful in providing an awareness of the intrinsic susceptibility of the fractured karstic groundwater system at the LSC to non-atmospheric anthropogenic inputs. The 3H/3He groundwater ages of spring discharge from the carbonate rocks showed transient behavior, with ages averaging about 2 a in 2004 following a wet climatic period (2003–2004), and ages in the range of 4–7 a in periods of more average precipitation (2008–2009). The SF6 and CFC-12 data indicate older water (model ages of 10s of years or more) in the low-permeability shale of the Martinsburg

  10. Correlation between geology and radon levels in groundwater, soil and indoor air in Bhilangana Valley, Garhwal Himalaya, India

    Energy Technology Data Exchange (ETDEWEB)

    Choubey, V.M. [Wadia Inst. of Himalayan Geology, Dehra Dun (India); Ramola, R.C. [Dept. of Physics, H.N.B. Garhwal Univ. Campus, Tehri Garhwal (India)

    1997-11-01

    Radon concentrations were measured in soil, air and groundwater in Bhilangana Valley, Garhwal Himalaya, India by using an LR-115 plastic track detector and radon emanometer. Radon concentrations were found to vary from 1 KBq/m{sup 3} to 57 KBq/m{sup 3} in soil, 5 Bq/l to 887 Bq/l in water and 95 Bq/m{sup 3} to 208 Bq/m{sup 3} in air. The recorded values are quite high due to associated uranium mineralization in the area. Radon concentration was also found to depend on the tectonic structure and geology of the area. (orig.)

  11. Statistical analysis of lake levels and field study of groundwater and surface-water exchanges in the northeast Twin Cities Metropolitan Area, Minnesota, 2002 through 2015: Chapter A of Water levels and groundwater and surface-water exchanges in lakes of the northeast Twin Cities Metropolitan Area, Minnesota, 2002 through 2015

    Science.gov (United States)

    Jones, Perry M.; Trost, Jared J.; Diekoff, Aliesha L.; Rosenberry, Donald O.; White, Eric A.; Erickson, Melinda L.; Morel, Daniel L.; Heck, Jessica M.

    2016-10-19

    Water levels declined from 2003 to 2011 in many lakes in Ramsey and Washington Counties in the northeast Twin Cities Metropolitan Area, Minnesota; however, water levels in other northeast Twin Cities Metropolitan Area lakes increased during the same period. Groundwater and surface-water exchanges can be important in determining lake levels where these exchanges are an important component of the water budget of a lake. An understanding of groundwater and surface-water exchanges in the northeast Twin Cities Metropolitan Area has been limited by the lack of hydrologic data. The U.S. Geological Survey, in cooperation with the Metropolitan Council and Minnesota Department of Health, completed a field and statistical study assessing lake-water levels and regional and local groundwater and surface-water exchanges near northeast Twin Cities Metropolitan Area lakes. This report documents the analysis of collected hydrologic, water-quality, and geophysical data; and existing hydrologic and geologic data to (1) assess the effect of physical setting and climate on lake-level fluctuations of selected lakes, (2) estimate potential percentages of surface-water contributions to well water across the northeast Twin Cities Metropolitan Area, (3) estimate general ages for waters extracted from the wells, and (4) assess groundwater inflow to lakes and lake-water outflow to aquifers downgradient from White Bear Lake. Statistical analyses of lake levels during short-term (2002–10) and long-term (1925–2014) periods were completed to help understand lake-level changes across the northeast Twin Cities Metropolitan Area. Comparison of 2002–10 lake levels to several landscape and geologic characteristics explained variability in lake-level changes for 96 northeast Twin Cities Metropolitan Area lakes. Application of several statistical methods determined that (1) closed-basin lakes (without an active outlet) had larger lake-level declines than flow-through lakes with an outlet; (2

  12. Behavioral response of manatees to variations in environmental sound levels

    Science.gov (United States)

    Miksis-Olds, J. L.; Wagner, T.

    2011-01-01

    Florida manatees (Trichechus manatus latirostris) inhabit coastal regions because they feed on the aquatic vegetation that grows in shallow waters, which are the same areas where human activities are greatest. Noise produced from anthropogenic and natural sources has the potential to affect these animals by eliciting responses ranging from mild behavioral changes to extreme aversion. Sound levels were calculated from recordings made throughout behavioral observation periods. An information theoretic approach was used to investigate the relationship between behavior patterns and sound level. Results indicated that elevated sound levels affect manatee activity and are a function of behavioral state. The proportion of time manatees spent feeding and milling changed in response to sound level. When ambient sound levels were highest, more time was spent in the directed, goal-oriented behavior of feeding, whereas less time was spent engaged in undirected behavior such as milling. This work illustrates how shifts in activity of individual manatees may be useful parameters for identifying impacts of noise on manatees and might inform population level effects. ?? 2010 by the Society for Marine Mammalogy.

  13. Linear response at the 4-component relativistic level

    DEFF Research Database (Denmark)

    Saue, T.; Jensen, Hans Jørgen Aagaard

    2003-01-01

    The theory, implementation, and application of linear response at the 4-component relativistic closed-shell Hartree-Fock level based on the concept of quasienergy and time averaging are reported. As such, an efficient AO-driven algorithm is obtained by assigning specific Hermiticity and time...... reversal symmetry to the trial vectors used in the solution of the reduced response equations. The given implementation has a quite general structure and thereby allows the calculation of a wide range of second-order properties such as polarizabilities, magnetizabilities, as well as NMR parameters....

  14. Determination of N-nitrosodimethylamine at part-per-trillion levels in drinking waters and contaminated groundwaters

    Energy Technology Data Exchange (ETDEWEB)

    Tomkins, B.A.; Griest, W.H.; Higgins, C.E.

    1995-12-01

    N-nitrosodimethylamine is a high, carcinogenic manufacturing by-product of unsymmetrical dimethyl hydrazine a component of rocket fuel. Prior disposal practices resulted in the contamination of groundwater near certain military installations with both species. The current regulatory threshold promulgated by the US Environmental Protection Agency (EPA) for NDMA in surface waters designated for drinking is 0.7 ng NDMA/L (0.7 pptr)L. Existing procedures for determining NDMA in aqueous samples typically employ dichloromethane extraction followed by concentration to a final volume of 1 mL, and gas chromatographic analysis of a 2 {mu}L aliquot of concentrate using either a nitrogen-phosphorus detector (NPD), mass spectrometric detector, or chemiluminescent nitrogen detector (CLND). Such a protocol does not permit detection of NDMA at the desired health-based criterion unless high-resolution mass spectrometric (HRMS) detectors are employed. The analytical procedure described in this work employed an initial solid-phase extraction of groundwater samples with a preconditioned Empore C{sub 18} disk, used to remove interfering neutral species including di-isopropylmethane phosphonate (DIMP), prior to continuous overnight extraction.

  15. Effect of irrigation return flow on groundwater recharge in an overexploited aquifer in Bangladesh

    Science.gov (United States)

    Touhidul Mustafa, Syed Md.; Shamsudduha, Mohammad; Huysmans, Marijke

    2016-04-01

    Irrigated agriculture has an important role in the food production to ensure food security of Bangladesh that is home to over 150 million people. However, overexploitation of groundwater for irrigation, particularly during the dry season, causes groundwater-level decline in areas where abstraction is high and surface geology inhibits direct recharge to underlying shallow aquifer. This is causing a number of potential adverse socio-economic, hydrogeological, and environmental problems in Bangladesh. Alluvial aquifers are primarily recharged during monsoon season from rainfall and surface sources. However, return flow from groundwater-fed irrigation can recharge during the dry months. Quantification of the effect of return flow from irrigation in the groundwater system is currently unclear but thought to be important to ensure sustainable management of the overexploited aquifer. The objective of the study is to investigate the effect of irrigation return flow on groundwater recharge in the north-western part of Bangladesh, also known as Barind Tract. A semi-physically based distributed water balance model (WetSpass-M) is used to simulate spatially distributed monthly groundwater recharge. Results show that, groundwater abstraction for irrigation in the study area has increased steadily over the last 29 years. During the monsoon season, local precipitation is the controlling factor of groundwater recharge; however, there is no trend in groundwater recharge during that period. During the dry season, however, irrigation return-flow plays a major role in recharging the aquifer in the irrigated area compared to local precipitation. Therefore, during the dry season, mean seasonal groundwater recharge has increased and almost doubled over the last 29 years as a result of increased abstraction for irrigation. The increase in groundwater recharge during dry season has however no significant effect in the improvement of groundwater levels. The relation between groundwater

  16. Biogeochemical responses to nutrient inputs in a Cuban coastal lagoon: runoff, anthropogenic, and groundwater sources.

    Science.gov (United States)

    González-De Zayas, R; Merino-Ibarra, M; Soto-Jiménez, M F; Castillo-Sandoval, F S

    2013-12-01

    Laguna Larga, a coastal lagoon in central Cuba, has been heavily altered by tourism infrastructure construction and sewage disposal. We hypothesize that this has decreased the circulation and caused eutrophication of the lagoon. To assess this, 12 bimonthly samplings were carried out in 2007-2008. Temperature, salinity, oxygen, nutrients and nitrogen, and phosphorous fractions (inorganic, organic, and total) were determined. Water and salt budgets, as well as biogeochemical fluxes of nitrogen and phosphorus were calculated using the LOICZ budget model for the three sections of the lagoon identified by morphological constrains and salinity patterns. Laguna Larga is a choked lagoon with restricted water circulation, low exchange, and high residence times that vary significantly along its sections. Residence time was estimated to be 0.1-0.7 years for the inner section and 1-9 days for the outer one. High levels of total nitrogen (annual means 126-137 μM, peaks up to 475 μM) and phosphorus (2.5-4.4 μM, peaks up to 14.5 μM) are evidence of eutrophication of Laguna Larga. During 2007, an average precipitation year, Laguna Larga exported water (703 m(3) d(-1)) and was a source of nitrogen (9.026 mmol m(-2) d(-1)) and phosphorus (0.112 mmol m(-2) d(-1)) to the adjacent sea. δ(15)N determinations in the seagrass Thalassia testudinum (-1.83 to +3.02 ‰) differed significantly between sites in the lagoon and offshore reference sites located W of the inlet, but were similar to those located E of the inlet. δ(15)N determinations in the seaweed Penicillus dumetosus (+1.02 to +4.2) did not show significant differences.

  17. Geospatial Data Used in Water-Level and Land-Subsidence Studies in the Mojave River and Morongo Groundwater Basins for 2004

    Data.gov (United States)

    U.S. Geological Survey, Department of the Interior — The Mojave River and Morongo ground-water basins are in the southwestern part of the Mojave Desert in southern California. Ground-water from these basins supplies a...

  18. Shallow groundwater in the Matanuska-Susitna Valley, Alaska—Conceptualization and simulation of flow

    Science.gov (United States)

    Kikuchi, Colin P.

    2013-01-01

    estimated during field investigations on several small streams. Regional groundwater flow patterns were characterized by synthesizing previous water-table maps with a synoptic water-level measurement conducted during 2009. Time-series water-level data were collected at groundwater and lake monitoring stations over the study period (2009–present). Comparison of historical groundwater-level records with time-series groundwater-level data collected during this study showed similar patterns in groundwater-level fluctuation in response to precipitation. Groundwater-age data collected during previous studies show that water moves quickly through the groundwater system, suggesting that the system responds quickly to changes in climate forcing. Similarly, the groundwater system quickly returns to long-term average conditions following variability due to seasonal or interannual changes in precipitation. These analyses indicate that the groundwater system is in a state of dynamic equilibrium, characterized by water-level fluctuation about a constant average state, with no long-term trends in aquifer-system storage. To address the second study goal, a steady-state groundwater flow model was developed to simulate regional groundwater flow patterns. The groundwater flow model was bounded by physically meaningful hydrologic features, and appropriate internal model boundaries were specified on the basis of conceptualization of the groundwater system resulting in a three-layer model. Calibration data included 173 water‑level measurements and 18 measurements of streamflow gains and losses along small streams. Comparison of simulated and observed heads and flows showed that the model accurately simulates important regional characteristics of the groundwater flow system. This model is therefore appropriate for studying regional-scale groundwater availability. Mismatch between model-simulated and observed hydrologic quantities is likely because of the coarse grid size of the model and

  19. Tidal Level Response to Sea-Level Rise in the Yangtze Estuary

    Institute of Scientific and Technical Information of China (English)

    GONG Zheng; ZHANG Chang-kuan; WAN Li-ming; ZUO Jun-cheng

    2012-01-01

    The rise of tidal level in tidal reaches induced by sea-level rise has a large impact on flood control and water supply for the regions around the estuary.This paper focuses on the variations of tidal level response along the tidal reaches in the Yangtze Estuary,as well as the impacts of upstream discharge on tidal level response,due to the sea-level rise of the East China Sea.Based on the Topex/Poseidon altimeter data obtained during the period 1993~2005,a stochastic dynamic analysis was performed and a forecast model was run to predict the sea-level rise of the East China Sea.Two-dimensional hydrodynamic numerical models downscaling from the East China Sea to estuarine areas were implemented to analyze the rise of tidal level along the tidal reaches.In response to the sea-level rise,the tidal wave characteristics change slightly in nearshore areas outside the estuaries,involving the tidal range and the duration of flood and ebb tide.The results show that the rise of tidal level in the tidal reaches due to the sea-level rise has upstream decreasing trends.The step between the stations of Zhangjiagang and Shiyiwei divides the tidal reaches into two parts,in which the tidal level response declines slightly.The rise of tidal level is 1~2.5 mm/a in the upper part,and 4~6 mm/a in the lower part.The stations of Jiangyin and Yanglin,as an example of the upper part and the lower part respectively,are extracted to analyze the impacts of upstream discharge on tidal level response to the sea-level rise.The relation between the rise of tidal level and the upstream discharge can be fitted well with a quadratic function in the upper part.However,the relation is too complicated to be fitted in the lower part because of the tide dominance.For comparison purposes,hourly tidal level observations at the stations of Xuliujing and Yanglin during the period 1993~2009 are adopted.In order to uniform the influence of upstream discharge on tidal level for a certain day each year

  20. Hanford Site ground-water monitoring for 1993

    Energy Technology Data Exchange (ETDEWEB)

    Dresel, P.E.; Luttrell, S.P.; Evans, J.C. [and others

    1994-09-01

    This report presents the results of the Ground-Water Surveillance Project monitoring for calendar year 1993 on the Hanford Site, Washington. Hanford Site operations from 1943 onward produced large quantities of radiological and chemical waste that have impacted ground-water quality on the Site. Monitoring of water levels and ground-water chemistry is performed to track the extent of contamination and trends in contaminant concentrations. The 1993 monitoring was also designed to identify emerging ground-water quality problems. The information obtained is used to verify compliance with applicable environmental regulations and to evaluate remedial actions. Data from other monitoring and characterization programs were incorporated to provide an integrated assessment of Site ground-water quality. Additional characterization of the Site`s geologic setting and hydrology was performed to support the interpretation of contaminant distributions. Numerical modeling of sitewide ground-water flow also supported the overall project goals. Water-level monitoring was performed to evaluate ground-water flow directions, to track changes in water levels, and to relate such changes to changes in site disposal practices. Water levels over most of the Hanford Site continued to decline between June 1992 and June 1993. The greatest declines occurred in the 200-West Area. These declines are part of the continued response to the cessation of discharge to U Pond and other disposal facilities. The low permeability in this area which enhanced mounding of waste-water discharge has also slowed the response to the reduction of disposal. Water levels remained nearly constant in the vicinity of B Pond, as a result of continued disposal to the pond. Water levels measured from wells in the unconfined aquifer north and east of the Columbia River indicate that the primary source of recharge is irrigation practices.

  1. High-fluoride groundwater.

    Science.gov (United States)

    Rao, N Subba

    2011-05-01

    Fluoride (F(-)) is essential for normal bone growth, but its higher concentration in the drinking water poses great health problems and fluorosis is common in many parts of India. The present paper deals with the aim of establishment of facts of the chemical characteristics responsible for the higher concentration of F(-) in the groundwater, after understanding the chemical behavior of F(-) in relation to pH, total alkalinity (TA), total hardness (TH), carbonate hardness (CH), non-carbonate hardness (NCH), and excess alkalinity (EA) in the groundwater observed from the known areas of endemic fluorosis zones of Andhra Pradesh that have abundant sources of F(-)-bearing minerals of the Precambrians. The chemical data of the groundwater shows that the pH increases with increase F(-); the concentration of TH is more than the concentration of TA at low F(-) groundwater, the resulting water is represented by NCH; the TH has less concentration compared to TA at high F(-) groundwater, causing the water that is characterized by EA; and the water of both low and high concentrations of F(-) has CH. As a result, the F(-) has a positive relation with pH and TA, and a negative relation with TH. The operating mechanism derived from these observations is that the F(-) is released from the source into the groundwater by geochemical reactions and that the groundwater in its flowpath is subjected to evapotranspiration due to the influence of dry climate, which accelerates a precipitation of CaCO(3) and a reduction of TH, and thereby a dissolution of F(-). Furthermore, the EA in the water activates the alkalinity in the areas of alkaline soils, leading to enrichment of F(-). Therefore, the alkaline condition, with high pH and EA, and low TH, is a more conducive environment for the higher concentration of F(-) in the groundwater.

  2. Kissing reduces allergic skin wheal responses and plasma neurotrophin levels.

    Science.gov (United States)

    Kimata, Hajime

    2003-11-01

    The effect of kissing on allergen-induced skin wheal responses and plasma neurotrophin levels were studied in 30 normal subjects, 30 patients with allergic rhinitis (AR), and 30 patients with atopic dermatitis (AD). All of the patients with AR or AD are allergic to house dust mite (HDM) and Japanese cedar pollen (JCP). They are all Japanese and they do not kiss habitually. The subject kissed freely during 30 min with their lover or spouse alone in a room with closed doors while listening to soft music. Before and after kissing, skin prick tests were performed using commercial HDM allergen, JCP allergen, as well as histamine and control solution, and wheal responses were measured. Simultaneously, plasma levels of neurotrophin, including nerve growth factor (NGF), brain-derived neurotrophic factor (BDNF), neurotrophin-3 (NT-3) and -4 (NT-4) were measured. Kissing significantly reduced wheal responses induced by HDM and JCP, but not by histamine, and decreased plasma levels of NGF, BDNF, NT-3, and NT-4 in patients with AR or AD, while it failed to do so in normal subjects. These finding indicate that kissing have some implication in the study of neuroimmunology in allergic patients.

  3. Groundwater arsenic and fluoride in Rajnandgaon District, Chhattisgarh, northeastern India

    Science.gov (United States)

    Patel, Khageshwar Singh; Sahu, Bharat Lal; Dahariya, Nohar Singh; Bhatia, Amarpreet; Patel, Raj Kishore; Matini, Laurent; Sracek, Ondra; Bhattacharya, Prosun

    2017-07-01

    The groundwater of Ambagarh Chouki, Rajnandgaon, India, shows elevated levels of As and F-, frequently above the WHO guidelines. In this work, the concentrations of As, F-, Na+, Mg2+, Ca2+, Cl-, SO4 2-, HCO3 -, Fe, dissolved organic carbon (DOC) and dissolved inorganic carbon (DIC) in the groundwater of Ambagarh Chouki are described. The sources of dissolved components in the groundwater are investigated using the cluster and factor analysis. Five factors have been identified and linked to processes responsible for the formation of groundwater chemistry. High concentrations of dissolved As seems to be linked to high concentrations of DOC, suggesting reductive dissolution of ferric oxyhydroxides as arsenic mobilization process. Fluoride is found in shallow depth water, presumably as a consequence of evaporation of water and removal of Ca2+ by precipitation of carbonates.

  4. Roles and responsibilities in the secondary level eye care model

    Directory of Open Access Journals (Sweden)

    Saibaba Saravanan

    2005-12-01

    Full Text Available In any secondary level eye care clinic, a number of tasks must be completed. In different countries and different settings, different people will carry out these tasks. The manager is responsible for ensuring that all the tasks are covered, that people are carefully selected to perform them, and that staff are supported and managed. The International Centre for Advancement of Rural Eye Care (ICARE, within the L.V. Prasad Eye Institute (LVPEI in India, has evolved an eye care team to provide secondary level eye care services to a population of 0.5 to 1 million. The ICARE model emphasises that all cadres of clinical and non-clinical personnel are equally important. Below is a description of the range of jobs at secondary level centres. The tertiary centre at LVPEI manages leadership and training for this model.

  5. Projecting avian response to linked changes in groundwater and riparian floodplain vegetation along a dryland river: a scenario analysis

    Science.gov (United States)

    Groundwater is a key driver of riparian condition on dryland rivers but is in high demand for municipal, industrial, and agricultural uses. Approaches are needed to guide decisions that balance human water needs while conserving riparian ecosystems. We developed a space-for-time substitution model ...

  6. Organizing groundwater regimes and response thresholds by soils: A framework for understanding runoff generation in a headwater catchment

    Science.gov (United States)

    John P. Gannon; Scott W. Bailey; Kevin J. McGuire

    2014-01-01

    A network of shallow groundwater wells in a headwater catchment at the Hubbard Brook Experimental Forest in New Hampshire, U.S. was used to investigate the hydrologic behavior of five distinct soil morphological units. The soil morphological units were hypothesized to be indicative of distinct water table regimes. Water table fluctuations in the wells were...

  7. Ground-water levels and water-quality data for wells in the Spring Creek area near Arnold Air Force Base, Tennessee, April and May 2000

    Science.gov (United States)

    Williams, Shannon D.; Aycock, Robert A.

    2001-01-01

    Arnold Air Force Base (AAFB) occupies about 40,000 acres in Coffee and Franklin Counties, Tennessee. Numerous site-specific ground-water contamination investigations have been conducted at designated solid waste management units (SWMU?s) at AAFB. Several synthetic volatile organic compounds (VOC?s), primarily chlorinated solvents, have been identified in groundwater samples collected from monitoring wells near SWMU 8 in the Spring Creek area. During April and May 2000, a study of the groundwater resources in the Spring Creek area was conducted to determine if VOC?s from AAFB have affected local private water supplies and to advance understanding of the ground-water-flow system in this area. The study focused on sampling private wells located within the Spring Creek area that are used as a source of drinking water. Ground-water-flow directions were determined by measuring water levels in wells and constructing a potentiometric-surface map of the Manchester aquifer in the study area. Data were collected from a total of 35 private wells and 22 monitoring wells during the period of study. Depths to ground water were determined for 22 of the private wells and all 22 of the monitoring wells. The wells ranged in depth from 21 to 105 feet. Water-level altitudes ranged from 930 to 1,062 feet above sea level. Depths to water ranged from 8 to 83 feet below land surface. Water-quality samples were collected from 29 private wells which draw water from either gravel zones in the upper part of the Manchester aquifer, fractured bedrock in the lower part of the Manchester aquifer, or a combination of these two zones. Concentrations of 50 of the 55 VOC?s analyzed for were less than method detection limits. Chloroform, acetone, chloromethane, 2-butanone, and tetrachloroethylene were detected in concentrations exceeding the method detection limits. Only chloroform and acetone were detected in concentrations equal to or exceeding reporting limits. Chloroform was detected in a sample

  8. Evaluation of Groundwater Impacts to Support the National Environmental Policy Act Environmental Assessment for the INL Remote-Handled Low-Level Waste Disposal Project

    Energy Technology Data Exchange (ETDEWEB)

    Annette Schafer, Arthur S. Rood, A. Jeffrey Sondrup

    2011-12-23

    Groundwater impacts have been analyzed for the proposed remote-handled low-level waste disposal facility. The analysis was prepared to support the National Environmental Policy Act environmental assessment for the top two ranked sites for the proposed disposal facility. A four-phase screening and analysis approach was documented and applied. Phase I screening was site independent and applied a radionuclide half-life cut-off of 1 year. Phase II screening applied the National Council on Radiation Protection analysis approach and was site independent. Phase III screening used a simplified transport model and site-specific geologic and hydrologic parameters. Phase III neglected the infiltration-reducing engineered cover, the sorption influence of the vault system, dispersion in the vadose zone, vertical dispersion in the aquifer, and the release of radionuclides from specific waste forms. These conservatisms were relaxed in the Phase IV analysis which used a different model with more realistic parameters and assumptions. Phase I screening eliminated 143 of the 246 radionuclides in the inventory from further consideration because each had a half-life less than 1 year. An additional 13 were removed because there was no ingestion dose coefficient available. Of the 90 radionuclides carried forward from Phase I, 57 radionuclides had simulated Phase II screening doses exceeding 0.4 mrem/year. Phase III and IV screening compared the maximum predicted radionuclide concentration in the aquifer to maximum contaminant levels. Of the 57 radionuclides carried forward from Phase II, six radionuclides were identified in Phase III as having simulated future aquifer concentrations exceeding maximum contaminant limits. An additional seven radionuclides had simulated Phase III groundwater concentrations exceeding 1/100th of their respective maximum contaminant levels and were also retained for Phase IV analysis. The Phase IV analysis predicted that none of the thirteen remaining

  9. Exercise responses in patients with chronically high creatine kinase levels.

    Science.gov (United States)

    Cooper, Christopher B; Dolezal, Brett A; Neufeld, Eric V; Shieh, Perry; Jenner, John R; Riley, Marshall

    2017-08-01

    Elevated serum creatine kinase (CK) is often taken to reflect muscle disease, but many individuals have elevated CK without a specific diagnosis. How elevated CK reflects muscle metabolism during exercise is not known. Participants (46 men, 48 women) underwent incremental exercise testing to assess aerobic performance, cardiovascular response, and ventilatory response. Serum lactate, ammonia, and CK were measured at rest, 4 minutes into exercise, and 2 minutes into recovery. High-CK and control subjects demonstrated similar aerobic capacities and cardiovascular responses to incremental exercise. Those with CK ≥ 300 U/L exhibited significantly higher lactate and ammonia levels after maximal exercise, together with increased ventilatory responses, whereas those with CK ≥200 U/L but ≤ 300 U/L did not. We recommend measurement of lactate and ammonia profiles during a maximal incremental exercise protocol to help identify patients who warrant muscle biopsy to rule out myopathy. Muscle Nerve 56: 264-270, 2017. © 2016 Wiley Periodicals, Inc.

  10. Biphasic dose response in low level light therapy - an update.

    Science.gov (United States)

    Huang, Ying-Ying; Sharma, Sulbha K; Carroll, James; Hamblin, Michael R

    2011-01-01

    Low-level laser (light) therapy (LLLT) has been known since 1967 but still remains controversial due to incomplete understanding of the basic mechanisms and the selection of inappropriate dosimetric parameters that led to negative studies. The biphasic dose-response or Arndt-Schulz curve in LLLT has been shown both in vitro studies and in animal experiments. This review will provide an update to our previous (Huang et al. 2009) coverage of this topic. In vitro mediators of LLLT such as adenosine triphosphate (ATP) and mitochondrial membrane potential show biphasic patterns, while others such as mitochondrial reactive oxygen species show a triphasic dose-response with two distinct peaks. The Janus nature of reactive oxygen species (ROS) that may act as a beneficial signaling molecule at low concentrations and a harmful cytotoxic agent at high concentrations, may partly explain the observed responses in vivo. Transcranial LLLT for traumatic brain injury (TBI) in mice shows a distinct biphasic pattern with peaks in beneficial neurological effects observed when the number of treatments is varied, and when the energy density of an individual treatment is varied. Further understanding of the extent to which biphasic dose responses apply in LLLT will be necessary to optimize clinical treatments.

  11. Enhancements to the Mississippi Embayment Regional Aquifer Study (MERAS) groundwater-flow model and simulations of sustainable water-level scenarios

    Science.gov (United States)

    Clark, Brian R.; Westerman, Drew A.; Fugitt, D. Todd

    2013-01-01

    Arkansas continues to be one of the largest users of groundwater in the Nation. As such, long-term planning and management are essential to ensure continued availability of groundwater and surface water for years to come. The Mississippi Embayment Regional Aquifer Study (MERAS) model was developed previously as a tool to evaluate groundwater availability within the Mississippi embayment, which encompasses much of eastern Arkansas where the majority of groundwater is used. The Arkansas Water Plan is being updated for the first time since 1990 and serves as the State’s primary, comprehensive water-resources planning and guidance document. The MERAS model was selected as the best available tool for evaluation of specific water-use pumping scenarios that are currently being considered by the State of Arkansas. The model, developed as part of the U.S. Geological Survey Groundwater Resources Program’s assessment of the Nation’s groundwater availability, is proving to be invaluable to the State as it works toward development of a sustained yield pumping strategy. One aspect of this investigation was to evaluate multiple methods to improve the match of observed to simulated groundwater levels within the Mississippi River Valley alluvial and middle Claiborne (Sparta) aquifers in the MERAS model. Five primary methods were evaluated: (1) explicit simulation of evapotranspiration (ET), (2) upgrade of the Multi-Node Well (MNW2) Package, (3) geometry improvement within the Streamflow Routing (SFR) Package, (4) parameter estimation of select aquifer properties with pilot points, and (5) modification of water-use estimates. For the planning purposes of the Arkansas Water Plan, three scenarios were developed to evaluate potential future conditions: (1) simulation of previously optimized pumping values within the Mississippi River Valley alluvial and the middle Claiborne aquifers, (2) simulated prolonged effects of pumping at average recent (2000–5) rates, and (3) simulation

  12. The response of mire vegetation to water level drawdown

    Science.gov (United States)

    Kurki, Kirsi; Laine, Jukka; Vasander, Harri; Tuittila, Eeva-Stiina

    2010-05-01

    Mires have a significant role in climate change mitigation due to their enormous carbon storage and due to the fluxes of greenhouse gases between ecosystem and the atmosphere. Mire vegetation is controlled by ecohydrology, climate and by the competition of plants on light and nutrients. The water logged conditions create a challenging environment for both vascular plants and bryophytes; therefore majority of plants growing in these habitats are highly specialized. Global warming is predicted to affect mire vegetation indirectly through increased evapotranspiration leading to decreased water table levels down to 14-22 centimeters. Water level drawdown is likely to affect the vegetation composition and consequently the ecosystem functioning of mires. Previous studies covering the first years following water table level drawdown have shown that vascular plants benefit from a lower water table and hollow-specific Sphagnum species suffer. In addition to changes in plant abundances the diversity of plant communities decreases. The lawn and hollow communities of Sphagna and sedges are found to be the most sensitive plant groups. It has been shown that surveys on vegetation changes can have different results depending on the time scale. The short and long term responses are likely vary in heterogenous mire vegetation; therefore predictions can be done more reliably with longer surveys. We applied BACI (before-after-control-impact) experimental approach to study the responses of different functional mire plant groups to water level drawdown. There are 3 control plots, 3 treatment plots with moderate water level drawdown and 3 plots drained for forestry 40 years ago as a reference. The plots are located in meso-, oligo- and ombrotrophic sites in Lakkasuo (Orivesi, Finland). The vegetation was surveyed from permanent sampling points before ditching in 2000 and during the years 2001-2003 and 2009. The data was analyzed with NMDS (PC-Ord) and DCA (CANOCO). Overall results show

  13. Status of groundwater levels and storage volume in the Equus Beds aquifer near Wichita, Kansas, January 2011

    Science.gov (United States)

    Hansen, Cristi V.

    2011-01-01

    The Equus Beds aquifer in southwestern Harvey County and northwestern Sedgwick County was developed to supply water to the city of Wichita and for irrigation in south-central Kansas. Water-level and storage-volume decreases that began with the development of the aquifer in the 1940s reached record to near-record lows in January 1993. Since 1993, the aquifer has been experiencing higher water levels and a partial recovery of storage volume. Potentiometric maps of the shallow and deep layers of the map show flow in both aquifer layers is generally from west to east. Water-level altitudes in the shallow aquifer layer ranged from a high of about 1,470 feet in the northwest corner of the study area to low of about 1,330 feet in the southeast corner of the study area; water-level altitudes in the deep aquifer layer ranged from a high of about 1,440 feet on the west edge of the study area to a low of about 1,330 feet in the southeast corner of the study area. In the northwest part of the study area, water-levels can be up to 50 feet higher in the shallow layer than in the deep layer of the Equus Beds aquifer. Measured water-level changes for August 1940 to January 2011 ranged from a decline of 16.52 feet to a rise of 2.22 feet. The change in storage volume from August 1940 to January 2011 was a decrease of about 104,000 acre-feet. This volume represents a recovery of about 151,000 acre-feet, or about 59 percent of the storage volume previously lost between August 1940 and January 1993. It also represents a recovery of about 63,000 acre-feet, or about 38 percent of the storage volume lost between August 1940 and January 2007. Major factors in these storage-volume recoveries are increased recharge from greater-than-normal precipitation and planned decreases in city pumpage that are part of Wichita's Integrated Local Water Supply Plan; however, part of the recovery may be because city and irrigation pumpage probably decreased in response to greater-than-normal precipitation

  14. Recalibration of a ground-water flow model of the Mississippi River Valley alluvial aquifer of northeastern Arkansas, 1918-1998, with simulations of water levels caused by projected ground-water withdrawals through 2049

    Science.gov (United States)

    Reed, Thomas B.

    2003-01-01

    A digital model of the Mississippi River Valley alluvial aquifer in eastern Arkansas was used to simulate ground-water flow for the period from 1918 to 2049. The model results were used to evaluate effects on water levels caused by demand for ground water from the alluvial aquifer, which has increased steadily for the last 40 years. The model results showed that water currently (1998) is being withdrawn from the aquifer at rates greater than what can be sustained for the long term. The saturated thickness of the alluvial aquifer has been reduced in some areas resulting in dry wells, degraded water quality, decreased water availability, increased pumping costs, and lower well yields. The model simulated the aquifer from a line just north of the Arkansas-Missouri border to south of the Arkansas River and on the east from the Mississippi River westward to the less permeable geologic units of Paleozoic age. The model consists of 2 layers, a grid of 184 rows by 156 columns, and comprises 14,118 active cells each measuring 1 mile on a side. It simulates time periods from 1918 to 1998 along with further time periods to 2049 testing different pumping scenarios. Model flux boundary conditions were specified for rivers, general head boundaries along parts of the western side of the model and parts of Crowleys Ridge, and a specified head boundary across the aquifer further north in Missouri. Model calibration was conducted for observed water levels for the years 1972, 1982, 1992, and 1998. The average absolute residual was 4.69 feet and the root-mean square error was 6.04 feet for the hydraulic head observations for 1998. Hydraulic-conductivity values obtained during the calibration process were 230 feet per day for the upper layer and ranged from 230 to 730 feet per day for the lower layer with the maximum mean for the combined aquifer of 480 feet per day. Specific yield values were 0.30 throughout the model and specific storage values were 0.000001 inverse-feet throughout

  15. MODFLOW-2000 model used to evaluate potential effects of existing and proposed groundwater withdrawals on water levels and natural groundwater discharge in Snake Valley and surrounding areas, Utah and Nevada

    Data.gov (United States)

    U.S. Geological Survey, Department of the Interior — A previously developed three-dimensional steady-state numerical groundwater-flow model was modified to transient conditions with respect to well withdrawals, and...

  16. Groundwater Depletion in Dhaka City, Bangladesh: A Spatio-temporal Analysis

    Science.gov (United States)

    Jerin, T.; Ishtiaque, A.

    2015-12-01

    Dhaka city, having a population of more than fifteen million, exclusively depends on groundwater as a source of quality drinking water. In recent decades the city is encountering groundwater diminution and the declining scenario is dissimilar in different parts of the city. This paper aims to discuss the groundwater depletion in different parts of Dhaka city from 1990 to 2012 along with the causes and consequences. Groundwater level data of different locations of Dhaka city were collected from Bangladesh Water Development Board (BWDB). The data were processed and analyzed using SPSS and Excel Worksheet; a contour map was generated using ArcGIS 10.0 to outline the contemporary groundwater scenario of Dhaka city and the spatial analyst tool, Inverse Distance Weighted (IDW) was used to prepare the map. In addition, experts' opinions were collected using an in-depth interview strategy in order to provide a better understanding of the causes and consequences of groundwater depletion. The research results show that groundwater in Dhaka city is depleting at an alarming rate; the central part has the worst situation followed by the south-western part. In contrast, northern part has relatively better groundwater condition. Moreover, the peripheral zone exhibits a better condition because of the existence of rivers and wetlands. The interviews reveal that population density and overexploitation are mainly responsible for groundwater depletion; however, various other factors such as the deliberate establishment of deep tube wells, reduction of recharge capacity due to rapid growth of urban structures altogether results in huge drop of water level throughout the city. Rapid decline in groundwater augments the city's exposure towards multiple risks including land subsidence, groundwater pollution and most importantly, paucity of available fresh water that might ultimately results into an urban disaster. Potential solutions to ameliorate this situation include urban greening

  17. Quantifying phosphorus levels in soils, plants, surface water, and shallow groundwater associated with bahiagrass-based pastures.

    Science.gov (United States)

    Sigua, Gilbert C; Hubbard, Robert K; Coleman, Samuel W

    2010-01-01

    Recent assessments of water quality status have identified eutrophication as one of the major causes of water quality 'impairment' not only in the USA but also around the world. In most cases, eutrophication has accelerated by increased inputs of phosphorus due to intensification of crop and animal production systems since the early 1990 s. Despite substantial measurements using both laboratory and field techniques, little is known about the spatial and temporal variability of phosphorus dynamics across landscapes, especially in agricultural landscapes with cow-calf operations. Critical to determining environmental balance and accountability is an understanding of phosphorus excreted by animals, phosphorus removal by plants, acceptable losses of phosphorus within the manure management and crop production systems into soil and waters, and export of phosphorus off-farm. Further research effort on optimizing forage-based cow-calf operations to improve pasture sustainability and protect water quality is therefore warranted. We hypothesized that properly managed cow-calf operations in subtropical agroecosystem would not be major contributors to excess loads of phosphorus in surface and ground water. To verify our hypothesis, we examined the comparative concentrations of total phosphorus among soils, forage, surface water, and groundwater beneath bahiagrass-based pastures with cow-calf operations in central Florida, USA. Soil samples were collected at 0-20; 20-40, 40-60, and 60-100 cm across the landscape (top slope, middle slope, and bottom slope) of 8 ha pasture in the fall and spring of 2004 to 2006. Forage availability and phosphorus uptake of bahiagrass were also measured from the top slope, middle slope, and bottom slope. Bi-weekly (2004-2006) groundwater and surface water samples were taken from wells located at top slope, middle slope, and bottom slope, and from the runoff/seepage area. Concentrations of phosphorus in soils, forage, surface water, and shallow

  18. Groundwater types in Southeast Srem

    Directory of Open Access Journals (Sweden)

    Gregorić Enike

    2009-01-01

    Full Text Available The region of Southeast Srem is rich in ground waters, which is of great significance to agricultural production. The objective of this paper was to designate the zones of different groundwater types from the aspect of recharge, based on the analysis of groundwater regimes in the study area. A very complex groundwater regime in Southeast Srem, which depends on a great number of natural and some anthropogenic factors, makes it difficult to designate clearly the zones of the three main types of groundwater regime. Still, the boundaries of the zones of groundwater regime types were defined based on the results of correlation analysis of the basic factors affecting the groundwater regime. Zone I includes the climatic type of groundwater. Its fluctuation corresponds to the vertical factors of water balance (precipitation and evaporation and it is not affected by the river water level. This zone extends North and East of the line Putinci, Golubinci, Stara Pazova, Batajnica, Dobanovci, mainly in the area of the loess plateau. Within the zone, groundwater is at a relatively great depth. Only exceptionally, in the valleys, it appears almost on the surface. Zone II includes the climatic-hydrological groundwater type, which is the transition between the climatic type and the hydrological type. The fluctuation of groundwater regime is affected both by the effect of vertical balance factors, and by the effect of watercourses. Climatic-hydrological groundwater type covers the central and the lowest part of the study area and the South part of the middle terrace. Zone III is classified as the hydrological groundwater type and it covers the riparian areas along the Sava and the Danube. The aquifer is hydraulically connected with the river Sava.

  19. Trophic level responses differ as climate warms in Ireland

    Science.gov (United States)

    Donnelly, Alison; Yu, Rong; Liu, Lingling

    2015-08-01

    Effective ecosystem functioning relies on successful species interaction. However, this delicate balance may be disrupted if species do not respond to environmental change at a similar rate. Here we examine trends in the timing of spring phenophases of groups of species occupying three trophic levels as a potential indicator of ecosystem response to climate warming in Ireland. The data sets were of varying length (1976-2009) and from varying locations: (1) timing of leaf unfolding and May Shoot of a range of broadleaf and conifer tree species, (2) first appearance dates of a range of moth species, and (3) first arrival dates of a range of spring migrant birds. All three groups revealed a statistically significant ( Psupply and demand. These differing trophic level response rates demonstrate the potential for a mismatch in the timing of interdependent phenophases as temperatures rise. Even though these data were not specifically collected to examine climate warming impacts, we conclude that such data may be used as an early warning indicator and as a means to monitor the potential for future ecosystem disruption to occur as climate warms.

  20. The groundwater recharge response and hydrologic services of tropical humid forest ecosystems to use and reforestation: Support for the “infiltration-evapotranspiration trade-off hypothesis”

    Science.gov (United States)

    Krishnaswamy, Jagdish; Bonell, Michael; Venkatesh, Basappa; Purandara, Bekal K.; Rakesh, K. N.; Lele, Sharachchandra; Kiran, M. C.; Reddy, Veerabasawant; Badiger, Shrinivas

    2013-08-01

    The hydrologic effects of forest use and reforestation of degraded lands in the humid tropics has implications for local and regional hydrologic services but such issues have been relatively less studied when compared to the impacts of forest conversion. In particular, the “infiltration-evapotranspiration trade-off” hypothesis which predicts a net gain or loss to baseflow and dry-season flow under both, forest degradation or reforestation depending on conditions has not been tested adequately. In the Western Ghats of India, we examined the hydrologic responses and groundwater recharge and hydrologic services linked with three ecosystems, (1) remnant tropical evergreen forest (NF), (2) heavily-used former evergreen forest which now has been converted to tree savanna, known as degraded forest(DF), and (3) exotic Acacia plantations (AC, Acacia auriculiformis) on degraded former forest land. Instrumented catchments ranging from 7 to 23 ha representing these three land-covers (3 NF, 4 AC and 4 DF, in total 11 basins), were established and maintained between 2003 and 2005 at three sites in two geomorphological zones, Coastal and Up-Ghat (Malnaad). Four larger (1-2 km2) catchments downstream of the head-water catchments in the Malnaad with varying proportions of different land-cover and providing irrigation water for areca-nut and paddy rice were also measured for post-monsoon baseflow. Daily hydrological and climate data was available at all the sites. In addition, 36 min data was available at the Coastal site for 41 days as part of the opening phase of the summer monsoon, June-July 2005. Low potential and actual evapotranspiration rates during the monsoon that are similar across all land-cover ensures that the main control on the extent of groundwater recharge during the south-west monsoon is the proportion of rainfall that is converted into quick flow rather than differences in evapotranspiration between the different land cover types. The Flow duration curves

  1. Quantifying human response capabilities towards tsunami threats at community level

    Science.gov (United States)

    Post, J.; Mück, M.; Zosseder, K.; Wegscheider, S.; Taubenböck, H.; Strunz, G.; Muhari, A.; Anwar, H. Z.; Birkmann, J.; Gebert, N.

    2009-04-01

    Decision makers at the community level need detailed information on tsunami risks in their area. Knowledge on potential hazard impact, exposed elements such as people, critical facilities and lifelines, people's coping capacity and recovery potential are crucial to plan precautionary measures for adaptation and to mitigate potential impacts of tsunamis on society and the environment. A crucial point within a people-centred tsunami risk assessment is to quantify the human response capabilities towards tsunami threats. Based on this quantification and spatial representation in maps tsunami affected and safe areas, difficult-to-evacuate areas, evacuation target points and evacuation routes can be assigned and used as an important contribution to e.g. community level evacuation planning. Major component in the quantification of human response capabilities towards tsunami impacts is the factor time. The human response capabilities depend on the estimated time of arrival (ETA) of a tsunami, the time until technical or natural warning signs (ToNW) can be received, the reaction time (RT) of the population (human understanding of a tsunami warning and the decision to take appropriate action), the evacuation time (ET, time people need to reach a safe area) and the actual available response time (RsT = ETA - ToNW - RT). If RsT is larger than ET, people in the respective areas are able to reach a safe area and rescue themselves. Critical areas possess RsT values equal or even smaller ET and hence people whin these areas will be directly affected by a tsunami. Quantifying the factor time is challenging and an attempt to this is presented here. The ETA can be derived by analyzing pre-computed tsunami scenarios for a respective area. For ToNW we assume that the early warning center is able to fulfil the Indonesian presidential decree to issue a warning within 5 minutes. RT is difficult as here human intrinsic factors as educational level, believe, tsunami knowledge and experience

  2. Guidelines for selecting codes for ground-water transport modeling of low-level waste burial sites. Volume 1. Guideline approach

    Energy Technology Data Exchange (ETDEWEB)

    Simmons, C.S.; Cole, C.R.

    1985-05-01

    This document was written for the National Low-Level Waste Management Program to provide guidance for managers and site operators who need to select ground-water transport codes for assessing shallow-land burial site performance. The guidance given in this report also serves the needs of applications-oriented users who work under the direction of a manager or site operator. The guidelines are published in two volumes designed to support the needs of users having different technical backgrounds. An executive summary, published separately, gives managers and site operators an overview of the main guideline report. This volume includes specific recommendations for decision-making managers and site operators on how to use these guidelines. The more detailed discussions about the code selection approach are provided. 242 refs., 6 figs.

  3. An immune response network associated with blood lipid levels.

    Directory of Open Access Journals (Sweden)

    Michael Inouye

    2010-09-01

    Full Text Available While recent scans for genetic variation associated with human disease have been immensely successful in uncovering large numbers of loci, far fewer studies have focused on the underlying pathways of disease pathogenesis. Many loci which are associated with disease and complex phenotypes map to non-coding, regulatory regions of the genome, indicating that modulation of gene transcription plays a key role. Thus, this study generated genome-wide profiles of both genetic and transcriptional variation from the total blood extracts of over 500 randomly-selected, unrelated individuals. Using measurements of blood lipids, key players in the progression of atherosclerosis, three levels of biological information are integrated in order to investigate the interactions between circulating leukocytes and proximal lipid compounds. Pair-wise correlations between gene expression and lipid concentration indicate a prominent role for basophil granulocytes and mast cells, cell types central to powerful allergic and inflammatory responses. Network analysis of gene co-expression showed that the top associations function as part of a single, previously unknown gene module, the Lipid Leukocyte (LL module. This module replicated in T cells from an independent cohort while also displaying potential tissue specificity. Further, genetic variation driving LL module expression included the single nucleotide polymorphism (SNP most strongly associated with serum immunoglobulin E (IgE levels, a key antibody in allergy. Structural Equation Modeling (SEM indicated that LL module is at least partially reactive to blood lipid levels. Taken together, this study uncovers a gene network linking blood lipids and circulating cell types and offers insight into the hypothesis that the inflammatory response plays a prominent role in metabolism and the potential control of atherogenesis.

  4. Simple chloride sensors for continuous groundwater monitoring

    DEFF Research Database (Denmark)

    Thorn, Paul; Mortensen, John

    2012-01-01

    The development of chloride sensors which can be used for continuous, on-line monitoring of groundwater could be very valuable in the management of our coastal water resources. However, sensor stability, drift, and durability all need to be addressed in order for the sensors to be used...... in continuous application. This study looks at the development of a simple, inexpensive chloride electrode, and evaluates its performance under continuous use, both in the laboratory and in a field test in a monitoring well. The results from the study showed a consistent response to changing chloride...... sensor remained responsive even at low chloride concentrations, where the conductivity electrode was no longer responding to changing chloride levels. With the results, it is believed that the simple chloride sensor could be used for continuous monitoring of groundwater quality....

  5. On mobilization of lead and arsenic in groundwater in response to CO2 leakage from deep geological storage

    Energy Technology Data Exchange (ETDEWEB)

    Zheng, L.; Apps, J.A.; Zhang, Y.; Xu, T.; Birkholzer, J.T.

    2009-07-01

    If carbon dioxide stored in deep saline aquifers were to leak into an overlying aquifer containing potable groundwater, the intruding CO{sub 2} would change the geochemical conditions and cause secondary effects mainly induced by changes in pH In particular, hazardous trace elements such as lead and arsenic, which are present in the aquifer host rock, could be mobilized. In an effort to evaluate the potential risks to potable water quality, reactive transport simulations were conducted to evaluate to what extent and mechanisms through which lead and arsenic might be mobilized by intrusion of CO{sub 2}. An earlier geochemical evaluation of more than 38,000 groundwater quality analyses from aquifers throughout the United States and an associated literature review provided the basis for setting up a reactive transport model and examining its sensitivity to model variation. The evaluation included identification of potential mineral hosts containing hazardous trace elements, characterization of the modal bulk mineralogy for an arenaceous aquifer, and augmentation of the required thermodynamic data. The reactive transport simulations suggest that CO{sub 2} ingress into a shallow aquifer can mobilize significant lead and arsenic, contaminating the groundwater near the location of intrusion and further downstream. Although substantial increases in aqueous concentrations are predicted compared to the background values, the maximum permitted concentration for arsenic in drinking water was exceeded in only a few cases, whereas that for lead was never exceeded.

  6. Groundwater Eruption in China Triggered By the 2004 Sumatra Earthquake

    Science.gov (United States)

    Shi, Z.; Wang, D.; Manga, M.; Wang, C. Y.; Wang, G.

    2014-12-01

    The 2004 Mw9.3 Sumatra earthquake initiated a large, sustained groundwater eruption in Guangdong, China, 3200 km away from the epicenter. The erupted water column reached a height of ~60 m above the ground surface when it was first sighted and the eruption lasted about 10 days. Estimated seismic energy density at the eruption site is only 0.046 J.m-3; thus it is surprising that the earthquake caused such an intense response. A field survey showed that a large amount of gaseous CO2 was released from groundwater during the eruption and suggested that the eruption was caused by the exsolution of CO2 from groundwater. In this study, we use numerical simulation to explore the mechanism of the well eruption. We apply tidal analysis to water level data from 2003 to 2006 to estimate the aquifer parameters before and after the earthquake; the hydraulic diffusivity inferred this way is 0.423 m2/s and 1.371 m2/s before and after the earthquake, respectively. Based on these parameters, we use TOUGH2, a widely used numerical program for simulating two-phase hydrothermal processes, to simulate the evolution of CO2 saturation, the velocity of erupted groundwater and pressure in the well-aquifer system after Sumatra earthquake. The simulations show that the earthquake may have triggered bubbles to nucleate from the CO2-rich groundwater and enhanced the aquifer permeability, leading to increased groundwater discharge to the well. Decreased pore-pressure in the aquifer caused greater exsolution of CO2 and greater discharge, leading to groundwater eruption. Exsolution of CO2 extends radially away from the wellbore as a function of time and the continued exsolution of CO2 sustained the eruption until pressure in the aquifer drops below hydrostatic, which is marked by a ~9 m drop in groundwater level from that before the earthquake. That earthquake trigger eruption and CO2 exsolution has implications for CO2 sequestration.

  7. The groundwater subsidy to vegetation: groundwater exchanges between landcover patches

    Science.gov (United States)

    Steven, L. I.; Gimenez, R.; Jobbagy, E. G.

    2015-12-01

    The Gran Chaco is a hot, dry plain, that spans over 60 million hectares across Bolivia, Paraguay, Brazil and Argentina. It supports high biodiversity in its dry forest and savannahs, but is rapidly being converted to agriculture in response to growing soy demand and technology including genetic modification and zero-till, that has made cultivation in drier landscapes more viable. Under natural conditions, the deep-rooted, native vegetation of the Chaco effectively captured all rainfall for evapotranspiration resulting in near zero groundwater recharge under the dry forest. Conversion to shallower rooted soy and corn, combined with the fallow period prior to the growing season, reduces evapotranspiration and allows some water to percolate through the root zone and recharge the groundwater system. When this groundwater recharge occurs, it creates groundwater mounding and a hydraulic gradient that drives flow to adjacent landcover patches where recharge does not occur. As the watertable rises, groundwater becomes available to the deep-rooted, dry forest vegetation. We develop a soil and groundwater flow model to simulate infiltration, percolation, evaporation, rootwater uptake, groundwater recharge and the lateral transfer of water between adjacent landcover patches to quantify this groundwater subsidy from converted agricultural lands to remnant patches of dry forest.

  8. Recharge and level change of shallow groundwater within the Lake Qinghai catchment%青海湖流域浅层地下水补给来源及其水位变化

    Institute of Scientific and Technical Information of China (English)

    金章东; 石岳威; 张飞

    2010-01-01

    inland shallow groundwater plays a key role in local drinking, irrigation and regional economic development, especially in semi-arid and arid areas. For the Lake Qinghai catchment, the recharge and table level of shallow groundwater are one of the most important essential factors for land ecology and vegetation conditions and for ongoing ecologic restoration tests on wetland, deserted and grass lands. Through an investigation of shallow groundwater table level in August 2009 and a comparison with that in august 2000, and analyses of hydrogen and oxygen isotopic compositions of shallow groundwater, river and rain water samples, the natural condition of isobaths of shallow groundwater table level within the Lake Qinghai catchment was demonstrated. The data indicate that precipitation is the major recharge source of shallow groundwater whose table levels are affected by precipitation amount and terrain, besides consumption by local residents.%地下水补给来源及水位变化是干旱–半干旱地区生态和植被的主要制约要素之一,也是开展流域生态和环境治理技术与试验示范的关键。通过青海湖流域2000年8月和2009年8月浅层地下水埋深的调查,以及地下水、河水和雨水氢氧同位素分析,揭示了青海湖流域浅层地下水埋深的基本状况,明确了大气降水是青海湖流域浅层地下水的主要补给来源,其水位变化受居民用水量的影响外,主要与降水量、地形密切相关。

  9. Bridging groundwater models and decision support with a Bayesian network

    Science.gov (United States)

    Fienen, Michael N.; Masterson, John P.; Plant, Nathaniel G.; Gutierrez, Benjamin T.; Thieler, E. Robert

    2013-01-01

    Resource managers need to make decisions to plan for future environmental conditions, particularly sea level rise, in the face of substantial uncertainty. Many interacting processes factor in to the decisions they face. Advances in process models and the quantification of uncertainty have made models a valuable tool for this purpose. Long-simulation runtimes and, often, numerical instability make linking process models impractical in many cases. A method for emulating the important connections between model input and forecasts, while propagating uncertainty, has the potential to provide a bridge between complicated numerical process models and the efficiency and stability needed for decision making. We explore this using a Bayesian network (BN) to emulate a groundwater flow model. We expand on previous approaches to validating a BN by calculating forecasting skill using cross validation of a groundwater model of Assateague Island in Virginia and Maryland, USA. This BN emulation was shown to capture the important groundwater-flow characteristics and uncertainty of the groundwater system because of its connection to island morphology and sea level. Forecast power metrics associated with the validation of multiple alternative BN designs guided the selection of an optimal level of BN complexity. Assateague island is an ideal test case for exploring a forecasting tool based on current conditions because the unique hydrogeomorphological variability of the island includes a range of settings indicative of past, current, and future conditions. The resulting BN is a valuable tool for exploring the response of groundwater conditions to sea level rise in decision support.

  10. Numerical simulation of groundwater level in a fractured porous medium and sensitivity analysis of the hydrodynamic parameters using grid computing: application of the plain of Gondo (Burkina Faso

    Directory of Open Access Journals (Sweden)

    Wenddabo Olivier Sawadogo

    2012-01-01

    Full Text Available The use of mathematical modeling as a tool for decision support is not common in Africa in solving development problems. In this article we talk about the numerical simulation of groundwater level of the plain of Gondo (Burkina Faso and the sensitivity analysis of the hydrodynamic parameters. The domain has fractures which have hydraulic coefficients lower than those of the rock. Our contribution is to bring brief replies to the real problem posed in the thesis of Mr. KOUSSOUBE [1]. Namely that what causes the appearance of the piezometric level observed and impact of surface water on the piezometry. The mathematical model of the flow was solved by programming the finite element method on FreeFem++[2]. A local refinement of the mesh at fracture was used. We then conduct a sensitivity analysis to see which hydrodynamic parameters influences much of the solution. The method used for the sensitivity analysis is based on the calculation of the gradient by the adjoint equation and requires great computational power. To remedy this, we used a technique of distributed computing and we launched our application to the Moroccan grid (magrid. This allowed us to reduce the computation time. The results allowed to highlight the role of fractures and contributions of surface water on the evolution of the piezometric level of the plain of Gondo and identified the parameters that greatly influence the piezometric level.

  11. 应用同位素方法识别高放废物处置库预选场址地下水的形成%Isotope Method for the Recognition of Groundwater Formation in China's Preselected High Level Radioactive Waste Disposal Repository Site

    Institute of Scientific and Technical Information of China (English)

    郭永海; 王驹; 刘淑芬; 苏锐; 吕川河

    2005-01-01

    Yemaquan region in Beishan area, Gansu province, is one of the preselected sites of disposal repository for high level radioactive waste (HLW) in our country. Hydrogeological condition is an important aspect for site evaluation and the groundwater formation is a key factor to reflect the hydrogeological conditions for a certain area. Isotopic method is the one of the important means to determine the groundwater formation. Through the sampling and analysis of shallow groundwater isotopes of Yemaquan region, combined with geological, hydrogeological and hydrogeochemical characteristics, the issue of groundwater formation in the study region was discussed. The main cognition is that the groundwater in the region was formed from the infiltration of modern rainfall and the strong evaporation was happened for the shallow groundwater, which indicates the circulation conditions were relatively good for the shallow groundwater. This cognition provides very important hydrgeological information and basis for the evaluation of Yemaquan preselected site.

  12. groundwater contribution to crop water requirement groundwater ...

    African Journals Online (AJOL)

    eobe

    Keywords: Groundwater, water table, capillary rise, soil type, waterleaf, ... GROUNDWATER CONTRIBUTION TO WATERLEAF (TALINUM TRIANGULARE) IN OXISOLS, I. J. ... Nutritionally, ... information to facilitate increased crop production,.

  13. Statistical analysis of lake levels and field study of groundwater and surface-water exchanges in the northeast Twin Cities Metropolitan Area, Minnesota, 2002 through 2015: Chapter A of Water levels and groundwater and surface-water exchanges in lakes of the northeast Twin Cities Metropolitan Area, Minnesota, 2002 through 2015

    Science.gov (United States)

    Jones, Perry M.; Trost, Jared J.; Diekoff, Aliesha L.; Rosenberry, Donald O.; White, Eric A.; Erickson, Melinda L.; Morel, Daniel L.; Heck, Jessica M.

    2016-10-19

    Water levels declined from 2003 to 2011 in many lakes in Ramsey and Washington Counties in the northeast Twin Cities Metropolitan Area, Minnesota; however, water levels in other northeast Twin Cities Metropolitan Area lakes increased during the same period. Groundwater and surface-water exchanges can be important in determining lake levels where these exchanges are an important component of the water budget of a lake. An understanding of groundwater and surface-water exchanges in the northeast Twin Cities Metropolitan Area has been limited by the lack of hydrologic data. The U.S. Geological Survey, in cooperation with the Metropolitan Council and Minnesota Department of Health, completed a field and statistical study assessing lake-water levels and regional and local groundwater and surface-water exchanges near northeast Twin Cities Metropolitan Area lakes. This report documents the analysis of collected hydrologic, water-quality, and geophysical data; and existing hydrologic and geologic data to (1) assess the effect of physical setting and climate on lake-level fluctuations of selected lakes, (2) estimate potential percentages of surface-water contributions to well water across the northeast Twin Cities Metropolitan Area, (3) estimate general ages for waters extracted from the wells, and (4) assess groundwater inflow to lakes and lake-water outflow to aquifers downgradient from White Bear Lake. Statistical analyses of lake levels during short-term (2002–10) and long-term (1925–2014) periods were completed to help understand lake-level changes across the northeast Twin Cities Metropolitan Area. Comparison of 2002–10 lake levels to several landscape and geologic characteristics explained variability in lake-level changes for 96 northeast Twin Cities Metropolitan Area lakes. Application of several statistical methods determined that (1) closed-basin lakes (without an active outlet) had larger lake-level declines than flow-through lakes with an outlet; (2

  14. Promoting local management in groundwater

    Science.gov (United States)

    van Steenbergen, Frank

    2006-03-01

    There is a strong case for making greater effort to promote local groundwater management—in addition to other measures that regulate groundwater use. Though scattered, there are several examples—from India, Pakistan, Yemen and Egypt—where groundwater users effectively self-imposed restrictions on the use of groundwater. There are a number of recurrent themes in such spontaneously-developed examples of local regulation: the importance of not excluding potential users; the importance of simple, low transaction cost rules; the power of correct and accessible hydrogeological information; the possibility of making more use of demand and supply management strategies; and the important supportive role of local governments. The case is made, using examples, for actively promoting local groundwater management as an important element in balancing groundwater uses. Two programmes for promoting local groundwater management in South India are described—one focussing on participatory hydrological monitoring, and one focussing on micro-resource planning and training. In both cases the response was very positive and the conclusion is that promoting local groundwater regulation is not difficult, costly or sensitive and can reach the necessary scale quickly.

  15. Tehran Groundwater Chemical Pollution

    Directory of Open Access Journals (Sweden)

    M- Shariatpanahi

    1990-06-01

    Full Text Available Seventy eight wells water sample of Tehran plain were examined to determine r its groundwaters chemical pollution. Tehran s groundwaters are slightly acidic and their total dissolved solids are high and are in the hard water category."nThe nitrate concentration of wells water of west region is less than per¬missible level of W.H.O. standard, whereas, the nitrate concentration of some of the other regions wells exceed W.H.O. standard which is indication of pollution"nwith municipal wastewaters. The concentration of toxic elements Cr, Cd, As, Hg and"ni Pb of some of the west, east and south regions wells of Tehran is more than per¬missible level of W.H.O. standard, whereas, the concentration of Cu, Zn,Mn and detergents is below W.H.O. standard."n1"nIn general, the amount of dissolved materials of Tehran s groundwaters and also"ni the potential of their contamination with nitrate is increased as Tehran s ground-"nwaters move further to the south, and even though, Tehran s groundwaters contamination with toxic elements is limited to the industrial west district, industrial-residential east and south districts, but»with regard to the disposal methods of"nt municipal and industrial wastewaters, if Tehran s groundwaters pollution continues,"nlocal contamination of groundwaters is likely to spread. So that finally their quality changes in such a way that this water source may become unfit for most domestic, industrial and agricultural uses. This survey shows the necessity of collection and treatment of Tehran s wastewaters and Prevention of the disposal of untreated wastewaters into the environment.

  16. Control of Groundwater Pollution from Animal Feeding Operations: A Farm-Level Dynamic Model for Policy Analysis

    Science.gov (United States)

    Wang, J.; Baerenklau, K.

    2012-12-01

    Consolidation in livestock production generates higher farm incomes due to economies of scale, but it also brings waste disposal problems. Over-application of animal waste on adjacent land produces adverse environmental and health effects, including groundwater nitrate pollution. The situation is particularly noticeable in California. In respond to this increasingly severe problem, EPA published a type of command-and-control regulation for concentrated animal feeding operations (CAFOs) in 2003. The key component of the regulation is its nutrient management plans (NMPs), which intend to limit the land application rates of animal waste. Although previous studies provide a full perspective on potential economic impacts for CAFOs to meet nutrient standards, their models are static and fail to reflect changes in management practices other than spreading manure on additional land and changing cropping patterns. We develop a dynamic environmental-economic modeling framework for representative CAFOs. The framework incorporates four models (i.e., animal model, crop model, hydrologic model, and economic model) that include various components such as herd management, manure handling system, crop rotation, water sources, irrigation system, waste disposal options, and pollutant emissions. We also include the dynamics of soil characteristics in the rootzone as well as the spatial heterogeneity of the irrigation system. The operator maximizes discounted total farm profit over multiple periods subject to environmental regulations. Decision rules from the dynamic optimization problem demonstrate best management practices for CAFOs to improve their economic and environmental performance. Results from policy simulations suggest that direct quantity restrictions of emission or incentive-based emission policies are much more cost-effective than the standard approach of limiting the amount of animal waste that may be applied to fields (as shown in the figure below); reason being

  17. A Contamination Vulnerability Assessment for the Sacramento Area Groundwater Basin

    Energy Technology Data Exchange (ETDEWEB)

    Moran, J E; Hudson, G B; Eaton, G F; Leif, R

    2004-03-10

    In response to concerns expressed by the California Legislature and the citizenry of the State of California, the State Water Resources Control Board (SWRCB), implemented a program to assess groundwater quality, and provide a predictive capability for identifying areas that are vulnerable to contamination. The program was initiated in response to concern over public supply well closures due to contamination by chemicals such as MtBE from gasoline, and solvents from industrial operations. As a result of this increased awareness regarding groundwater quality, the Supplemental Report of the 1999 Budget Act mandated the SWRCB to develop a comprehensive ambient groundwater-monitoring plan, and led to the initiation of the Ambient Groundwater Monitoring and Assessment (GAMA) Program. The primary objective of the GAMA Program is to assess the water quality and to predict the relative susceptibility to contamination of groundwater resources throughout the state of California. Under the GAMA program, scientists from Lawrence Livermore National Laboratory (LLNL) collaborate with the SWRCB, the U.S. Geological Survey, the California Department of Health Services (DHS), and the California Department of Water Resources (DWR) to implement the groundwater assessment program in cooperation with local water purveyors. In 2001 and 2002, LLNL carried out this vulnerability study in the groundwater basin of Sacramento suburban area, located to the north of the American River and to the east of the Sacramento River. The goal of the study is to provide a probabilistic assessment of the relative vulnerability of groundwater used for the public water supply to contamination from surface sources. This assessment of relative contamination vulnerability is made based on the results of two types of analyses that are not routinely carried out at public water supply wells: ultra low-level measurement of volatile organic compounds (VOCs), and groundwater age dating (using the tritium-helium-3

  18. Influence of groundwater level change on vegetation coverage and their spatial variation in arid regions%地下水位变化对干旱区植被盖度的影响及其空间变异特征

    Institute of Scientific and Technical Information of China (English)

    苏里坦; 宋郁东; 玛丽娜

    2004-01-01

    Sampling and testing are conducted on groundwater depth and vegetation coverage in the 670 km2 of the Sangong River Basin and semi-variance function analysis is made afterwards on the data obtained by the application of geo-statistics. Results showed that the variance curve of the groundwater depth and vegetation coverage displays an exponential model. Analysis of sampling data in 2003 indicates that the groundwater depth and vegetation coverage change similarly in space in this area. The Sangong River Basin is composed of upper oasis, middle ecotone and lower sand dune. In oasis and ecotone, influenced by irrigation of the adjoining oasis, groundwater level has been raised and soil water content also increased compared with sand dune nearby, vegetation developed well. But in the lower reaches of the Sangong River Basin, because of descending of groundwater level, soil water content decreased and vegetation degenerated. From oasis to abandoned land and desert grassland, vegetation coverage and groundwater level changed greatly with significant difference respectively in spatial variation. Distinct but similar spatial variability exists among the groundwater depth and vegetation coverage in the study area, namely, the vegetation coverage decreasing (increasing) as the groundwater depth increases (decreases). This illustrates the great dependence of vegetation coverage on groundwater depth in arid regions and further implies that among the great number of factors affecting vegetation coverage in arid regions, groundwater depth tums out to be the most determinant one.

  19. Groundwater salinisation in the Wadden Sea area of the Netherlands: quantifying the effects of climate change, sea level rise and anthropogenic interferences

    NARCIS (Netherlands)

    Pauw, P.S.; Louw, de P.G.B.; Oude Essink, G.H.P.

    2012-01-01

    Hydrogeological research in coastal areas has gained considerable attention over the last decades due to increasing stresses on fresh groundwater resources. Fundamental groundwater flow and solute transport analyses remain essential for a concise understanding of the governing processes that lead to

  20. Estimating Groundwater Development area in Jianan Plain using Standardized Groundwater Index

    Science.gov (United States)

    Yu, Chang Hsiang; Haw, Lee Cheng

    2017-04-01

    Taiwan has been facing severe water crises in recent years owing to the effects of extreme weather conditions. Changes in precipitation patterns have also made the drought phenomenon increasingly prominent, which has indirectly affected groundwater recharge. Hence, in the present study, long-term monitoring data were collected from the study area of the Jianan plain. The standardized groundwater index (SGI) and was then used to analyse the region's drought characteristics. To analyse the groundwater level by using SGI, making SGI180 groundwater level be the medium water crises, and SGI360 groundwater level be the extreme water crises. Through the different water crises signal in SGI180 and SGI360, we divide groundwater in Jianan plain into two sections. Thereby the water crises indicators establishing groundwater level standard line in Jianan Plain, then using the groundwater level standard line to find the study area where could be groundwater development area in Jianan plain. Taking into account relatively more water scarcity in dry season, so the study screen out another emergency backup groundwater development area, but the long-term groundwater development area is still as a priority development area. After finding suitable locations, groundwater modeling systems(GMS) software is used to simulate our sites to evaluate development volume. Finally, the result of study will help the government to grasp the water shortage situation immediately and solve the problem of water resources deployment.

  1. 干旱引黄灌区地下水位变化特征分析%Changing Characteristics of Groundwater Level of the Yellow River Irrigation Area in Arid Region

    Institute of Scientific and Technical Information of China (English)

    徐存东; 王荣荣; 丁廉营; 温钦钰; 连海东

    2016-01-01

    In order to study the changing characteristics of groundwater level of different groundwater movement zones in the arid Yellow River irrigation area, the stage I project of Jingtaichuan electrical lifting irrigation area in Gansu Province ( hereinafter called as"JID") was selected as the typical representative and the basic data was the real⁃time monitoring data of groundwater level in this area from 1982 to 2011. The inter⁃annual variation trend of groundwater level was analyzed based on Mann⁃Kendall test and the intra⁃annual variation was analyzed through the comparison of groundwater level monthly average curve of every 15 years. The results show that account for the seasonal irrigation, regional terrain and artificial exploitation, the inter⁃annual and intra⁃annual variation of different groundwater movement zones in the irrigation area has obvious difference;exploiting groundwater in groundwater accumulation zone for irrigation can effectively control the local salinization of the irrigation area.%为研究干旱引黄灌区不同地下水运动带的地下水位变化特征,以甘肃省景电一期灌区为例,利用其1982—2011年实测地下水位数据,采用Mann-Kendall趋势检验法分析了地下水位的年际变化趋势,并根据每15 a逐月的地下水位均值曲线,对地下水位的年内变化特征进行了研究。结果表明:受季节性灌溉、区域地势、人为开采等因素的影响,不同地下水运动带地下水位年际、年内变化趋势存在较大差异;在灌区汇水区域适当发展井灌,有利于土地盐渍化的控制。

  2. Shallow Groundwater Movement in the Skagit River Delta Area, Skagit County, Washington

    Science.gov (United States)

    Savoca, Mark E.; Johnson, Kenneth H.; Fasser, Elisabeth T.

    2009-01-01

    levels rise from October through March, when precipitation is high, and decline from April through September, when precipitation is lower. Groundwater levels in wells along the eastern margin of the study area also are likely influenced by stage on the Skagit River. Water levels in these wells remained elevated through April, and did not seem to begin to decline until the end of May in response to declining river stage. Groundwater levels in a well equipped with a continuous water-level recorder exhibited periodic fluctuations that are characteristic of ocean tides. This well is less than 1 mile east of the tidally influenced Swinomish Channel, and exhibited water-level fluctuations that correspond closely to predicted tidal extremes obtained from a tide gage near La Conner, Washington.

  3. 基于GIS的再生水利用对地下水位影响的研究%Effect of Reclaimed Water Useage on Groundwater Level Based on GIS

    Institute of Scientific and Technical Information of China (English)

    蒙格平; 尹世洋; 张桂芳; 杨再俊; 张平

    2012-01-01

    基于ArcGIS9.3应用软件,系统分析了北京市大兴区地下水时空变化规律及蓄变特征,比较了不同区域地下埋深的变化。结果表明:大兴区的地下水埋深程逐年加大趋势,地下水储量逐年减少;2002年开始大量利用再生水以后,大兴区南红门再生水灌区的地下水位下降速度小于灌区以外的区域。%Based on ArcG1S9. 3, characteristics of the temporal & spatial variation and accumulator variation of groundwater level of Daxing district in Beijing were analyzed , and changes of groundwater depth in different areas were compared. The results showed that groundwater depth of Daxing district increased year by year, while the storage of groundwater decreased continuously; With the extensive use of reclaimed water from 2002, rate for the decline of groundwater in Nanhongmen reclaimed water irrigation district was slower than that in other area.

  4. Analysis on Variation Law of Groundwater Level in Yinbei Irrigation Region of Ningxia%宁夏银北灌区地下水位变化规律分析

    Institute of Scientific and Technical Information of China (English)

    孙根火

    2012-01-01

    The causes for higher groundwater level in Yinbei irrigation region were analyzed, the annual and inner-year dynamic variation law was studied. The main influencing factors on irrigation area groundwater level variation was determined by using principle component analysis method. The results showed that the groundwater level has cyclicity and seasonal characteristics. Affected by random factors, the groundwater level is relatively stable among years. The main factors for variation is induction water amount, degradation water amount a nd precipitation.%分析了银北灌区地下水位较高的成因,研究了灌区地下水位年际和年内的动态变化规律,采用主成分分析方法确定了灌区地下水位变化的主要影响因素.研究结果表明,灌区地下水位具有周期性、季节性变化的特点,受随机性因素的影响,在年际间相对稳定;影响灌区地下水位变化的主要因素是引水量、退水量、降水量.

  5. Modelling of the effect of a sea-level rise and land subsidence on the evolution of the groundwater density in the subsoil of the northern part of the Netherlands

    NARCIS (Netherlands)

    Meij, J.L. van der; Minnema, B.

    1999-01-01

    The Province of Friesland is conducting a study on possible future changes in the surface water and groundwater systems of Friesland. The aim of the study is to assess what changes might be caused by land subsidence and a rise in sea level - focusing in particular on the salinization of the surface

  6. Water quality, discharge, and groundwater levels in the Palomas, Mesilla, and Hueco Basins in New Mexico and Texas from below Caballo Reservoir, New Mexico, to Fort Quitman, Texas, 1889-2013

    Science.gov (United States)

    McKean, Sarah E.; Matherne, Anne Marie; Thomas, Nicole

    2014-01-01

    The U.S. Geological Survey, in cooperation with the New Mexico Environment Department, compiled data from various sources to develop a dataset that can be used to conduct an assessment of the total dissolved solids in surface water and groundwater of the Palomas, Mesilla, and Hueco Basins in New Mexico and Texas, from below Caballo Reservoir, N. Mex., to Fort Quitman, Tex. Data include continuous surface-water discharge records at various locations on the Rio Grande; surface-water-quality data for the Rio Grande collected at selected locations in the Palomas, Mesilla, and Hueco Basins; groundwater levels and groundwater-quality data collected from selected wells in the Palomas and Mesilla Basins; and data from several seepage investigations conducted on the Rio Grande and selected drains in the Mesilla Basin.

  7. Groundwater and Terrestrial Water Storage

    Science.gov (United States)

    Rodell, Matthew; Chambers, Don P.; Famiglietti, James S.

    2012-01-01

    Groundwater is a vital resource and also a dynamic component of the water cycle. Unconfined aquifer storage is less responsive to short term weather conditions than the near surface terrestrial water storage (TWS) components (soil moisture, surface water, and snow). However, save for the permanently frozen regions, it typically exhibits a larger range of variability over multi-annual periods than the other components. Groundwater is poorly monitored at the global scale, but terrestrial water storage (TWS) change data from the Gravity Recovery and Climate Experiment (GRACE) satellite mission are a reasonable proxy for unconfined groundwater at climatic scales.

  8. Quality-assurance plan for groundwater activities, U.S. Geological Survey, Washington Water Science Center

    Science.gov (United States)

    Kozar, Mark D.; Kahle, Sue C.

    2013-01-01

    This report documents the standard procedures, policies, and field methods used by the U.S. Geological Survey’s (USGS) Washington Water Science Center staff for activities related to the collection, processing, analysis, storage, and publication of groundwater data. This groundwater quality-assurance plan changes through time to accommodate new methods and requirements developed by the Washington Water Science Center and the USGS Office of Groundwater. The plan is based largely on requirements and guidelines provided by the USGS Office of Groundwater, or the USGS Water Mission Area. Regular updates to this plan represent an integral part of the quality-assurance process. Because numerous policy memoranda have been issued by the Office of Groundwater since the previous groundwater quality assurance plan was written, this report is a substantial revision of the previous report, supplants it, and contains significant additional policies not covered in the previous report. This updated plan includes information related to the organization and responsibilities of USGS Washington Water Science Center staff, training, safety, project proposal development, project review procedures, data collection activities, data processing activities, report review procedures, and archiving of field data and interpretative information pertaining to groundwater flow models, borehole aquifer tests, and aquifer tests. Important updates from the previous groundwater quality assurance plan include: (1) procedures for documenting and archiving of groundwater flow models; (2) revisions to procedures and policies for the creation of sites in the Groundwater Site Inventory database; (3) adoption of new water-level forms to be used within the USGS Washington Water Science Center; (4) procedures for future creation of borehole geophysics, surface geophysics, and aquifer-test archives; and (5) use of the USGS Multi Optional Network Key Entry System software for entry of routine water-level data

  9. Application of inverse modeling technique to describe hydrogeochemical processes responsible to spatial distribution of groundwater quality along flowpath

    Directory of Open Access Journals (Sweden)

    Tjahyo NugrohoAdji

    2013-07-01

    The result shows that firstly, the aquifer within the research area can be grouped into several aquifer systems (i.e. denudational hill, colluvial plain, alluvial plain, and beach ridges from recharge to discharge which generally have potential groundwater resources in terms of the depth and fluctuation of groundwater table. Secondly, flownets analysis gives three flowpaths that are plausible to be modeled in order to describe their hydrogeochemical reactions. Thirdly, the Saturation Indices (SI analysis shows that there are a positive correlation between the mineral occurrence and composition and the value of SI from recharge to discharge. In addition, The Mass Balance Model indicates that dissolution and precipitation of aquifer minerals is dominantly change the chemical composition along flowpath and the rate of the mass transfer between two wells shows a discrepancy and be certain of the percentage of the nature of aquifer mineral. Lastly, there is an interesting characteristic of mass balance chemical reaction occurs which is the entire chemical reaction shows that the sum of smallest mineral fmmol/litre will firstly always totally be reacted.

  10. Modeling soil water-salt dynamics and maize yield responses to groundwater depths and irrigations%土壤水盐与玉米产量对地下水埋深及灌溉响应模拟

    Institute of Scientific and Technical Information of China (English)

    郝远远; 徐旭; 黄权中; 黄冠华

    2014-01-01

    引黄水量的削减将进一步加剧宁夏银北灌区农业用水短缺问题,合理应用地下水进行灌溉对保障作物产量具有重要意义。为探究地下水灌溉条件下土壤水盐与作物生长的互馈机制,该研究修正了HYDRUS-1D的土壤蒸发模块,并嵌入可模拟作物生长与产量的 EPIC 模块,以此提高该模型在农田水文过程模拟中的适用性。采用2008年银北灌区不同水质灌水处理的玉米田间试验数据对模型进行了率定与验证。进一步应用该模型探寻地下水灌溉条件下,土壤水盐动态及玉米产量对地下水埋深变动及灌溉的响应规律。结果表明,玉米产量随地下水埋深增大呈现先增后减趋势,为保障玉米产量应将地下水适宜埋深控制在140~155 cm,且灌水量不宜低于现状灌水量,即玉米生育期内灌3水,每次900 m3/hm2。该研究对干旱银北灌区农业生产具有重要意义。%Reduction of water diversion from the Yellow River will intensify water shortage problems in the Yinbei Irrigation District (YID). Reasonable use of groundwater for irrigation is helpful to maintain the agricultural production. Groundwater exploitation may cause groundwater level declines in local areas. This helps to reduce the salinity accumulation in the root zone but decreases the capillary rise. Thus, it is important to figure out the responses of soil water-salt dynamics and crop yields to groundwater table fluctuations for salinity control and stable yields. In this study, HYDRUS-1D model was modified by coupling with the EPIC (erosion-productivity impact calculator) crop growth module for simulating agro-hydrological processes. The new crop module could simulate crop height, leaf area index (LAI), above-ground biomass and crop yield. The information between HYDRUS-1D and EPIC was exchanged by daily step. Root water uptake under water and salt stress was calculated with HYDRUS-1D and imported to EPIC to

  11. Annual Report of Groundwater Monitoring at Centralia, Kansas, in 2012

    Energy Technology Data Exchange (ETDEWEB)

    LaFreniere, Lorraine M. [Argonne National Lab. (ANL), Argonne, IL (United States)

    2013-06-01

    Periodic sampling is performed at Centralia, Kansas, on behalf of the Commodity Credit Corporation of the U.S. Department of Agriculture (CCC/USDA) by Argonne National Laboratory. The sampling is currently (2009-2012) conducted in accord with a monitoring program approved by the Kansas Department of Health and Environment (KDHE 2009). The objective is to monitor levels of carbon tetrachloride contamination identified in the groundwater sitewide (Argonne 2003, 2004, 2005a), as well as the response to the interim measure (IM) pilot test that is in progress (Argonne 2007b). This report provides a summary of the findings for groundwater inspection in Centralia.

  12. PATHS groundwater hydrologic model

    Energy Technology Data Exchange (ETDEWEB)

    Nelson, R.W.; Schur, J.A.

    1980-04-01

    A preliminary evaluation capability for two-dimensional groundwater pollution problems was developed as part of the Transport Modeling Task for the Waste Isolation Safety Assessment Program (WISAP). Our approach was to use the data limitations as a guide in setting the level of modeling detail. PATHS Groundwater Hydrologic Model is the first level (simplest) idealized hybrid analytical/numerical model for two-dimensional, saturated groundwater flow and single component transport; homogeneous geology. This document consists of the description of the PATHS groundwater hydrologic model. The preliminary evaluation capability prepared for WISAP, including the enhancements that were made because of the authors' experience using the earlier capability is described. Appendixes A through D supplement the report as follows: complete derivations of the background equations are provided in Appendix A. Appendix B is a comprehensive set of instructions for users of PATHS. It is written for users who have little or no experience with computers. Appendix C is for the programmer. It contains information on how input parameters are passed between programs in the system. It also contains program listings and test case listing. Appendix D is a definition of terms.

  13. Earth's free oscillations excited by the 2011 Tohoku Mw 9.0 earthquake detected with a groundwater level array in mainland China

    Science.gov (United States)

    Yan, Rui; Woith, Heiko; Wang, Rongjiang; Zhang, Yong

    2016-09-01

    Earth's free oscillations excited by a mega-thrust earthquake were observed by a continent-scale array of groundwater monitoring sites for the first time. After the occurrence of the 2011 Tohoku Mw 9.0 earthquake, water level records at 43 out of 216 wells in the China mainland revealed long-period free oscillation signals. In the time domain, these free oscillations exhibit globe circling Rayleigh surface waves. In some single wells, even the globe-circling Rayleigh wave R7 was visible, which travels three times around the Earth after the first arrival and appears about 10 hr after the earthquake occurrence in the present case. The spectral analysis shows that the principal oscillatory fluctuations seen in the water level records correspond to the spheroidal modes 0Sl (l = 2-31 for frequencies between 0.3 and 5.0 mHz) of the Earth's free oscillation. Especially at quiet sites, the spheroidal modes at very low frequencies (conditions.

  14. The Role of Groundwater for Lake-Water Quality and Quantification of N Seepage.

    Science.gov (United States)

    Kidmose, Jacob; Engesgaard, Peter; Ommen, Daniela A Oliveira; Nilsson, Bertel; Flindt, Mogens R; Andersen, Frede Ø

    2015-01-01

    The heterogeneous nature of both groundwater discharge to a lake (inflow) and nitrate concentrations in groundwater can lead to significant errors in calculations of nutrient loading. Therefore, an integrated approach, combining groundwater flow and transport modelling with observed nitrate and ammonium groundwater concentrations, was used to estimate nitrate loading from a catchment via groundwater to an oligotrophic flow-through lake (Lake Hampen, Denmark). The transport model was calibrated against three vertical nitrate profiles from multi-level wells and 17 shallow wells bordering a crop field near the lake. Nitrate concentrations in groundwater discharging to the lake from the crop field were on average 70 times higher than in groundwater from forested areas. The crop field was responsible for 96% of the total nitrate loading (16.2 t NO3 /year) to the lake even though the field only covered 4.5% of the catchment area. Consequently, a small change in land use in the catchment will have a large effect on the lake nutrient balance and possible lake restoration. The study is the first known attempt to estimate the decrease of nitrate