Modeling the local biodiversity impacts of agricultural water use: case study of a wetland in the coastal arid area of Peru.

Science.gov (United States)

Verones, Francesca; Bartl, Karin; Pfister, Stephan; Jiménez Vílchez, Ricardo; Hellweg, Stefanie

2012-05-01

Global water use is dominated by agriculture and has considerable influence on people's livelihood and ecosystems, especially in semiarid and arid regions. Methods to address the impacts of water withdrawal and consumption on terrestrial and aquatic ecosystems within life cycle assessment are still sparse and very generic. Regionalized characterization factors (CFs) for a groundwater-fed wetland at the arid coast of Peru are developed for groundwater and surface water withdrawal and consumption in order to address the spatial dependency of water use related impacts. Several agricultural scenarios for 2020 were developed in a workshop with local stakeholders and used for calculating total biodiversity impacts. In contrast to assumptions used in top-down approaches (e.g., Pfister et al. Environ. Sci Technol. 2009, 43, 4098 ), irrigation with surface water leads in this specific region to benefits for the groundwater-fed wetland, due to additional groundwater recharge from surplus irrigation water. However, irrigation with groundwater leads to ecological damage to the wetland. The CFs derived from the different scenarios are similar and can thus be used as general CFs for this region, helping local decision-makers to plan future agricultural development, including irrigation technologies, crop choices, and protection of the wetland. © 2012 American Chemical Society

Estimation of Net Groundwater Recharge Using Natural Drawdown Events in Subtropical Isolated Wetland Ecosystems

Science.gov (United States)

Perkins, D. B.; Min, J.; Jawitz, J. W.

2008-12-01

Restoration of ditched and drained wetlands in the Lake Okeechobee basin, Florida, USA is currently under study for possible amelioration of anthropogenic phosphorus enrichment of the lake. To date most research in this area has focused on the biogeochemical role of these wetlands. Here we focus on the dynamic hydrology of these systems and the resulting control on biogeochemical cycling. Four depressional wetlands in the basin were monitored for approximately three years to understand the interaction between wetland surface water and adjacent upland groundwater system. A coupled hydrologic-biogeochemical model was created to evaluate restoration scenarios. Determining wetland-scale hydraulic conductivity was an important aspect of the hydrologic model. Based on natural drawdown events observed at wetland-upland well pairs, hydraulic conductivities of top sandy soil layers surrounding the isolated wetlands were calculated using the Dupuit equation under a constrained water budget framework. The drawdown-based hydraulic conductivity estimates of 1.1 to 18.7 m/d (geometric mean of 4.8 m/d) were about three times greater than slug test- based values (1.5 ± 1.1 m/d), which is consistent with scale-dependent expectations. Model-based net groundwater recharge rate at each depressional wetland was predicted based on the estimated hydraulic conductivities, which corresponded to 50 to 72% of rainfall in the same period. These variances appeared to be due to the relative difference of ditch bottom elevation controlling the surface runoff as well as the spatial heterogeneity of the sandy aquifer. Results from this study have implications for nutrient loads to Lake Okeechobee via groundwater as well as water quality monitoring and management strategies aimed to reduce solute export (especially P) from the upstream catchment area to Lake Okeechobee.

Solute transport by groundwater flow to wetland ecosystems : the environmental impact of human activities

NARCIS (Netherlands)

Schot, P.P.

1991-01-01

This thesis deals with solute transport by groundwater flow and the way in which solute transport is affected by human activities. This in relation to wetland ecosystems. Wetlands in the eastern part of the Vecht river plain in The Netherlands are historically renown for their great variety of

Seawater-groundwater exchange and nutrients carried by submarine groundwater discharge in different types of wetlands at Jiaozhou Bay, China

Science.gov (United States)

Qu, Wenjing; Li, Hailong; Huang, Hao; Zheng, Chunmiao; Wang, Chaoyue; Wang, Xuejing; Zhang, Yan

2017-12-01

In Jiaozhou Bay, there are four wetland types, including sandy beaches, mud flats, tidal marshes, and estuarine intertidal zones. Four typical transects representing each of the wetland types were selected to investigate the flow dynamics, seawater-groundwater exchange and nutrients carried by submarine groundwater discharge (SGD). Based on field measurements of groundwater heads and salinity along each transect, the SGD averaged over the observation period was estimated using generalized Darcy's law. The SGD along the four transects ranges from 3.6 × 10-3 to 7.6 cm/d with the maximum occurring at the sandy beach. The SGD rate has a good correlation with the hydraulic conductivities of the wetland sediments. There is a positive correlation between the ratio of NO3-N/DIN and SGD rates. The SGD-associated nutrient output rate ranges from 3.3 × 10-2 to 9.5 mmol/m2/d for DIN (dissolved inorganic nitrogen), and from 6.2 × 10-5 to 1.8 × 10-2 mmol/m2/d for DIP (dissolved inorganic phosphorus). Compared to the nutrients delivered by the river, nutrients carried by SGD provide a more important source for the phosphate-limited environment to plankton in Jiaozhou Bay.

Assessment of in situ biodegradation of monochlorobenzene in contaminated groundwater treated in a constructed wetland

International Nuclear Information System (INIS)

Braeckevelt, Mareike; Rokadia, Hemal; Imfeld, Gwenael; Stelzer, Nicole; Paschke, Heidrun; Kuschk, Peter; Kaestner, Matthias; Richnow, Hans-H.; Weber, Stefanie

2007-01-01

The degradation of monochlorobenzene (MCB) was assessed in a constructed wetland treating MCB contaminated groundwater using a detailed geochemical characterisation, stable isotope composition analysis and in situ microcosm experiments. A correlation between ferrous iron mobilisation, decreasing MCB concentration and enrichment in carbon isotope composition was visible at increasing distance from the inflow point, indicating biodegradation of MCB in the wetland. Additionally, in situ microcosm systems loaded with 13 C-labelled MCB were deployed for the first time in sediments to investigate the biotransformation of MCB. Incorporation of 13 C-labelled carbon derived from the MCB into bacterial fatty acids substantiated in situ degradation of MCB. The detection of 13 C-labelled benzene indicated reductive dehalogenation of MCB. This integrated approach indicated the natural attenuation of the MCB in a wetland system. Further investigations are required to document and optimise the in situ biodegradation of MCB in constructed and natural wetland systems treating contaminated groundwater. - An integrated approach including isotope composition analysis and in situ microcosm experiments provided evidences for in situ biodegradation of MCB in a wetland system

Assessment of in situ biodegradation of monochlorobenzene in contaminated groundwater treated in a constructed wetland

Energy Technology Data Exchange (ETDEWEB)

Braeckevelt, Mareike [Departments of Bioremediation, Helmholtz Centre for Environmental Research - UFZ, Permoserstrasse 15, Leipzig D-04318, Saxonia (Germany); Rokadia, Hemal [Department of Isotope Biogeochemistry, Helmholtz Centre for Environmental Research - UFZ, Permoserstrasse 15, Leipzig D-04318, Saxonia (Germany); Imfeld, Gwenael [Department of Isotope Biogeochemistry, Helmholtz Centre for Environmental Research - UFZ, Permoserstrasse 15, Leipzig D-04318, Saxonia (Germany)]. E-mail: gwenael.imfeld@ufz.de; Stelzer, Nicole [Department of Isotope Biogeochemistry, Helmholtz Centre for Environmental Research - UFZ, Permoserstrasse 15, Leipzig D-04318, Saxonia (Germany); Paschke, Heidrun [Department of Analytical Chemistry, Helmholtz Centre for Environmental Research - UFZ, Permoserstrasse 15, Leipzig D-04318, Saxonia (Germany); Kuschk, Peter [Departments of Bioremediation, Helmholtz Centre for Environmental Research - UFZ, Permoserstrasse 15, Leipzig D-04318, Saxonia (Germany); Kaestner, Matthias [Departments of Bioremediation, Helmholtz Centre for Environmental Research - UFZ, Permoserstrasse 15, Leipzig D-04318, Saxonia (Germany); Richnow, Hans-H. [Department of Isotope Biogeochemistry, Helmholtz Centre for Environmental Research - UFZ, Permoserstrasse 15, Leipzig D-04318, Saxonia (Germany); Weber, Stefanie [Department of Isotope Biogeochemistry, Helmholtz Centre for Environmental Research - UFZ, Permoserstrasse 15, Leipzig D-04318, Saxonia (Germany)

2007-07-15

The degradation of monochlorobenzene (MCB) was assessed in a constructed wetland treating MCB contaminated groundwater using a detailed geochemical characterisation, stable isotope composition analysis and in situ microcosm experiments. A correlation between ferrous iron mobilisation, decreasing MCB concentration and enrichment in carbon isotope composition was visible at increasing distance from the inflow point, indicating biodegradation of MCB in the wetland. Additionally, in situ microcosm systems loaded with {sup 13}C-labelled MCB were deployed for the first time in sediments to investigate the biotransformation of MCB. Incorporation of {sup 13}C-labelled carbon derived from the MCB into bacterial fatty acids substantiated in situ degradation of MCB. The detection of {sup 13}C-labelled benzene indicated reductive dehalogenation of MCB. This integrated approach indicated the natural attenuation of the MCB in a wetland system. Further investigations are required to document and optimise the in situ biodegradation of MCB in constructed and natural wetland systems treating contaminated groundwater. - An integrated approach including isotope composition analysis and in situ microcosm experiments provided evidences for in situ biodegradation of MCB in a wetland system.

Placing prairie pothole wetlands along spatial and temporal continua to improve integration of wetland function in ecological investigations

Science.gov (United States)

Euliss, Ned H.; Mushet, David M.; Newton, Wesley E.; Otto, Clint R.V.; Nelson, Richard D.; LaBaugh, James W.; Scherff, Eric J.; Rosenberry, Donald O.

2014-01-01

We evaluated the efficacy of using chemical characteristics to rank wetland relation to surface and groundwater along a hydrologic continuum ranging from groundwater recharge to groundwater discharge. We used 27 years (1974–2002) of water chemistry data from 15 prairie pothole wetlands and known hydrologic connections of these wetlands to groundwater to evaluate spatial and temporal patterns in chemical characteristics that correspond to the unique ecosystem functions each wetland performed. Due to the mineral content and the low permeability rate of glacial till and soils, salinity of wetland waters increased along a continuum of wetland relation to groundwater recharge, flow-through or discharge. Mean inter-annual specific conductance (a proxy for salinity) increased along this continuum from wetlands that recharge groundwater being fresh to wetlands that receive groundwater discharge being the most saline, and wetlands that both recharge and discharge to groundwater (i.e., groundwater flow-through wetlands) being of intermediate salinity. The primary axis from a principal component analysis revealed that specific conductance (and major ions affecting conductance) explained 71% of the variation in wetland chemistry over the 27 years of this investigation. We found that long-term averages from this axis were useful to identify a wetland’s long-term relation to surface and groundwater. Yearly or seasonal measurements of specific conductance can be less definitive because of highly dynamic inter- and intra-annual climate cycles that affect water volumes and the interaction of groundwater and geologic materials, and thereby influence the chemical composition of wetland waters. The influence of wetland relation to surface and groundwater on water chemistry has application in many scientific disciplines and is especially needed to improve ecological understanding in wetland investigations. We suggest ways that monitoring in situ wetland conditions could be linked

Hydrology of prairie wetlands: Understanding the integrated surface-water and groundwater processes

Science.gov (United States)

Hayashi, Masaki; van der Kamp, Garth; Rosenberry, Donald O.

2016-01-01

Wetland managers and policy makers need to make decisions based on a sound scientific understanding of hydrological and ecological functions of wetlands. This article presents an overview of the hydrology of prairie wetlands intended for managers, policy makers, and researchers new to this field (e.g., graduate students), and a quantitative conceptual framework for understanding the hydrological functions of prairie wetlands and their responses to changes in climate and land use. The existence of prairie wetlands in the semi-arid environment of the Prairie-Pothole Region (PPR) depends on the lateral inputs of runoff water from their catchments because mean annual potential evaporation exceeds precipitation in the PPR. Therefore, it is critically important to consider wetlands and catchments as highly integrated hydrological units. The water balance of individual wetlands is strongly influenced by runoff from the catchment and the exchange of groundwater between the central pond and its moist margin. Land-use practices in the catchment have a sensitive effect on runoff and hence the water balance. Surface and subsurface storage and connectivity among individual wetlands controls the diversity of pond permanence within a wetland complex, resulting in a variety of eco-hydrological functionalities necessary for maintaining the integrity of prairie-wetland ecosystems.

Potential impacts of climate change on groundwater supplies to the Doñana wetland, Spain

OpenAIRE

Jackson, Christopher R.; Guardiola-Albert, Carolina

2011-01-01

Climate change impacts on natural recharge and groundwater-wetland dynamics were investigated for the Almonte-Marismas aquifer, Spain, which supports the internationally important Doñana wetland. Simulations were carried out using outputs from 13 global climate models to assess the impacts of climate change. Reductions in flow from the aquifer to streams and springs flooding the wetland, induced by changes in recharge according to different climate projections, were modelled. The results proj...

Phytoremediation of explosives in groundwater using innovative wetlands-based treatment technologies

Energy Technology Data Exchange (ETDEWEB)

Sikora, F.J.; Behrends, L.L.; Coonrod, H.S.; Phillips, W.D. [Tennessee Valley Authority, Muscle Shoals, AL (United States). Environmental Research Center; Bader, D.F. [Army Environmental Center, Aberdeen Proving Ground, MD (United States)

1997-12-31

Many army ammunition plants across the country have problems with groundwater contaminated with explosives. A field demonstration was initiated at the Milan Army Ammunition Plant near Milan, Tennessee early in 1996 to demonstrate the feasibility of treating contaminated groundwater with constructed wetlands. Two different systems were designed and installed. A lagoon system consisted of two cells in series with each cell having dimensions of 24 x 9.4 x 0.6 m (L x W x H). A gravel-bed system consisted of three gravel-beds operated in series with a primary anaerobic cell having dimensions of 32 x 11 x 1.4 m (L x W x H), followed by a pair of secondary cells each with dimensions of 5.5 x 11 x 1.4 m (L x W x H). The primary cell is maintained anaerobic by adding powdered milk to the water every two weeks. The secondary cells are maintained aerobic via reciprocation, whereby water is pumped back and forth from one cell to another to cause a recurrent fill and drain action. The lagoons were planted with sago pond weed, water stargrass, elodea, and parrot feather. The gravel-bed wetlands were planted with canary grass, wool grass, sweet flag, and parrot feather. Water began flowing to each of the wetland treatment systems at 19 L min{sup {minus}1} starting in June 1996. The design hydraulic retention time through each treatment system was approximately 10 days. Influent and effluent water samples were collected every 2 weeks. Intensive sampling of water interior to the wetlands occurred every 2 months.

Comammox Nitrospira are key nitrifiers in diverse groundwater-fed drinking water filters

DEFF Research Database (Denmark)

Fowler, Jane; Palomo, Alejandro; Smets, Barth F.

Nitrification is a dominant process in groundwater-fed rapid sand filters (RSFs) used for drinking water purification. Near complete removal of ammonium and nitrite is required in the EU and Denmark due to strict regulatory limits that enable high water stability in the distribution system. RSFs...... this work provides a new assay for the simultaneous detection of clade A and B comammox Nitrospira and expands our current knowledge of the diversity of comammox Nitrospira, while attempting to explain the success of comammox Nitrospira in these groundwater-fed filters....

Groundwater fluxes in a shallow seasonal wetland pond: The effect of bathymetric uncertainty on predicted water and solute balances

Science.gov (United States)

Trigg, Mark A.; Cook, Peter G.; Brunner, Philip

2014-09-01

The successful management of groundwater dependent shallow seasonal wetlands requires a sound understanding of groundwater fluxes. However, such fluxes are hard to quantify. Water volume and solute mass balance models can be used in order to derive an estimate of groundwater fluxes within such systems. This approach is particularly attractive, as it can be undertaken using measurable environmental variables, such as; rainfall, evaporation, pond level and salinity. Groundwater fluxes estimated from such an approach are subject to uncertainty in the measured variables as well as in the process representation and in parameters within the model. However, the shallow nature of seasonal wetland ponds means water volume and surface area can change rapidly and non-linearly with depth, requiring an accurate representation of the wetland pond bathymetry. Unfortunately, detailed bathymetry is rarely available and simplifying assumptions regarding the bathymetry have to be made. However, the implications of these assumptions are typically not quantified. We systematically quantify the uncertainty implications for eight different representations of wetland bathymetry for a shallow seasonal wetland pond in South Australia. The predictive uncertainty estimation methods provided in the Model-Independent Parameter Estimation and Uncertainty Analysis software (PEST) are used to quantify the effect of bathymetric uncertainty on the modelled fluxes. We demonstrate that bathymetry can be successfully represented within the model in a simple parametric form using a cubic Bézier curve, allowing an assessment of bathymetric uncertainty due to measurement error and survey detail on the derived groundwater fluxes compared with the fixed bathymetry models. Findings show that different bathymetry conceptualisations can result in very different mass balance components and hence process conceptualisations, despite equally good fits to observed data, potentially leading to poor management

Environmental restoration: Integrating hydraulic control of groundwater, innovative contaminant removal technologies and wetlands restoration--A case study at SRS

International Nuclear Information System (INIS)

Lewis, C.M.; Serkiz, S.M.; Adams, J.; Welty, M.

1992-01-01

The groundwater remediation program at the F and H Seepage Basins, Savannah River Sits (SRS) is a case study of the integration of various environmental restoration technologies at a single waste site. Hydraulic control measures are being designed to mitigate the discharge of groundwater plumes to surface water. One of the primary constituents of the plumes is tritium. An extraction and reinjection scenario is being designed to keep the tritium in circulation in the shallow groundwater, until it can naturally decay. This will be accomplished by extracting groundwater downgradient of the waste sites, treatment, and reinjection of the tritiated water into the water table upgradient of the basins. Innovative in-situ technologies, including electrolytic migration, are being field tested at the site to augment the pump-treat-reinject system. The in-situ technologies target removal of contaminants which are relatively immobile, yet represent long term risks to human health and the environment. Wetland restoration is an integral part of the F and H remediation program. Both in-situ treatment of the groundwater discharging the wetlands to adjust the pH, and replacement of water loss due to the groundwater extraction program ar being considered. Toxicity studies indicate that drought and the effects of low pH groundwater discharge have been factors in observed tree mortality in wetlands near the waste sites

Integrated Modeling of Groundwater and Surface Water Interactions in a Manmade Wetland

Directory of Open Access Journals (Sweden)

Guobiao Huang Gour-Tsyh Yeh

2012-01-01

Full Text Available A manmade pilot wetland in south Florida, the Everglades Nutrient Removal (ENR project, was modeled with a physics-based integrated approach using WASH123D (Yeh et al. 2006. Storm water is routed into the treatment wetland for phosphorus removal by plant and sediment uptake. It overlies a highly permeable surficial groundwater aquifer. Strong surface water and groundwater interactions are a key component of the hydrologic processes. The site has extensive field measurement and monitoring tools that provide point scale and distributed data on surface water levels, groundwater levels, and the physical range of hydraulic parameters and hydrologic fluxes. Previous hydrologic and hydrodynamic modeling studies have treated seepage losses empirically by some simple regression equations and, only surface water flows are modeled in detail. Several years of operational data are available and were used in model historical matching and validation. The validity of a diffusion wave approximation for two-dimensional overland flow (in the region with very flat topography was also tested. The uniqueness of this modeling study is notable for (1 the point scale and distributed comparison of model results with observed data; (2 model parameters based on available field test data; and (3 water flows in the study area include two-dimensional overland flow, hydraulic structures/levees, three-dimensional subsurface flow and one-dimensional canal flow and their interactions. This study demonstrates the need and the utility of a physics-based modeling approach for strong surface water and groundwater interactions.

Long-term changes in pond permanence, size, and salinity in Prairie Pothole Region wetlands: The role of groundwater-pond interaction

Science.gov (United States)

LaBaugh, James W.; Rosenberry, Donald O.; Mushet, David M.; Neff, Brian; Nelson, Richard D.; Euliss, Ned H.

2018-01-01

Study RegionCottonwood Lake area wetlands, North Dakota, U.S.A.Study FocusFluctuations in pond permanence, size, and salinity are key features of prairie-pothole wetlands that provide a variety of wetland habitats for waterfowl in the northern prairie of North America. Observation of water-level and salinity fluctuations in a semi-permanent wetland pond over a 20-year period, included periods when the wetland occasionally was dry, as well as wetter years when the pond depth and surface extent doubled while volume increased 10 times.New hydrological insights for the study regionCompared to all other measured budget components, groundwater flow into the pond often contributed the least water (8–28 percent) but the largest amount (>90 percent) of specific solutes to the water and solute budgets of the pond. In drier years flow from the pond into groundwater represented > 10 percent of water loss, and in 1992 was approximately equal to evapotranspiration loss. Also during the drier years, export of calcium, magnesium, sodium, potassium, chloride, and sulfate by flow from the pond to groundwater was substantial compared with previous or subsequent years, a process that would have been undetected if groundwater flux had been calculated as a net value. Independent quantification of water and solute gains and losses were essential to understand controls on water-level and salinity fluctuations in the pond in response to variable climate conditions.

Comparison of groundwater quality from forested (Waimarino River), urban (Turangi), and natural wetland (South Taupo Wetlands) subcatchments at the southern end of Lake Taupo

International Nuclear Information System (INIS)

Rosen, M.R.; Reeves, R.R.; Eser, P.; Chague-Goff, C.; Coshell, L.

1998-01-01

Comparison of groundwater quality of three different land uses, (1) exotic pine plantation ready for harvest (Waimarino River Catchment), (2) an urban area characterised by a land treatment facility for sewage effluent from Turangi (Turangi oxidation ponds), and (3) a natural wetland (South Taupo Wetlands) demonstrates that groundwater quality in the southern region of the Lake Taupo catchment is controlled by both natural and human influences in the area. Comparative water quality issues can be summarised as follows. (1) Naturally high concentrations of reduced iron and manganese are present in all three study areas, with the highest concentrations found in the natural wetland area and around the Turangi land treatment facility. (2) Concentrations of sodium, chloride, potassium, and ammonium in the groundwater down-gradient of the Turangi oxidation ponds are elevated relative to the other two study areas. Stable isotopic signatures also show that the groundwater has been influenced by surface water from the oxidation ponds, mostly due to additional evaporation caused by the relatively long residence time of the water (125 days) in the oxidation ponds. Elevated concentrations of ammonium also occur in deep groundwater under the forest areas of the Waimarino River catchment. (3) The water at all three sites is generally unsuitable for drinking supplies due to naturally elevated concentrations of reduced iron and manganese in the groundwater and elevated concentrations of ammonium at many monitoring sites, particularly around the Turangi land treatment site and the Waimarino deep aquifer monitoring sites. Aeration followed by settling or filtration of the groundwater could significantly reduce the concentrations of iron and manganese. (4) Elevated concentrations of reduced iron and manganese are unlikely to affect the water quality of Lake Taupo as all reduced iron and manganese will be oxidised once the water reaches the lake and precipitate as oxyhydroxide minerals

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

Chlorobenzene removal efficiencies and removal processes in a pilot-scale constructed wetland treating contaminated groundwater

DEFF Research Database (Denmark)

Braeckevelt, M.; Reiche, N.; Trapp, Stefan

2011-01-01

Low-chlorinated benzenes (CBs) are widespread groundwater contaminants and often threaten to contaminate surface waters. Constructed wetlands (CWs) in river floodplains are a promising technology for protecting sensitive surface water bodies from the impact of CBs. The efficiency and seasonal var...

Using Remote Sensing to Evaluate Wetland Recovery in the Northern Tampa Bay Area Following Reduction in Groundwater Withdrawals

Science.gov (United States)

Elder, Amor

In the past, the Northern Tampa Bay Area (NTBA) wetlands saw severe declines in hydrologic conditions due to excessive groundwater withdrawal rates. Eventually these rates were reduced to allow the wetlands to recover. To monitor this recovery, the Southwest Florida Water Management district (SWFWMD) set up a fieldwork based scoring methodology, called the Wetlands Assessment Procedure (WAP). WAP has been used in many studies of the area since groundwater withdrawal reductions; with many of those studies finding the recovery to be mixed at best. However, these studies were very limited in the number of wetlands they could assess due to the limitations of fieldwork. Therefore, it was proposed that remotely sensed variables associated with water consumption and stress be used to assess the recovery of the NTBA wetlands, as remote sensing allows for efficient assessments of targets over large area. Utilizing ASTER imagery scenes from 2005 and 2014, 211 wetlands' remotely sensed responses of NDVI, Land Surface Temperature (LST), and Evapotranspiration (ET) were mapped and statistically examined for trends indicating improvement or decline. Furthermore, a subset of WAP scores for the two years were examined and compared to the remotely sensed values. The results were contradictory, with remotely sensed responses showing an improvement over the time period, WAP scores indicating a decline in hydrologic conditions, and the two methods showing little to no fit when modeled against each other. As such, it is believed at this time that the remotely sensed method is not suitable for measuring the indicators of wetland recovery used in the WAP methodology.

Potential effects of climate change on riparian areas, wetlands, and groundwater-dependent ecosystems in the Blue Mountains, Oregon, USA

Directory of Open Access Journals (Sweden)

Kathleen A. Dwire

2018-04-01

Full Text Available Riparian areas, wetlands, and groundwater-dependent ecosystems, which are found at all elevations throughout the Blue Mountains, comprise a small portion of the landscape but have high conservation value because they provide habitat for diverse flora and fauna. The effects of climate change on these special habitats may be especially profound, due to altered snowpack and hydrologic regimes predicted to occur in the near future. The functionality of many riparian areas is currently compromised by water diversions and livestock grazing, which reduces their resilience to additional stresses that a warmer climate may bring. Areas associated with springs and small streams will probably experience near-term changes, and some riparian areas and wetlands may decrease in size over time. A warmer climate and reduced soil moisture could lead to a transition from riparian hardwood species to more drought tolerant conifers and shrubs. Increased frequency and spatial extent of wildfire spreading from upland forests could also affect riparian species composition. The specific effects of climate change will vary, depending on local hydrology (especially groundwater, topography, streamside microclimates, and current conditions and land use. Keywords: Climate change, Groundwater-dependent ecosystems, Riparian areas, Springs, Wetlands

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.

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

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

Hydroecological impacts of climate change modelled for a lowland UK wetland

Science.gov (United States)

House, Andrew; Acreman, Mike; Sorensen, James; Thompson, Julian

2015-04-01

Conservation management of wetlands often rests on modifying hydrological functions to establish or maintain desired flora and fauna. Hence the ability to predict the impacts of climate change is highly beneficial. Here, the physically based, distributed model MIKE SHE was used to simulate hydrology for the Lambourn Observatory at Boxford, UK. This comprises a 10 ha lowland riparian wetland protected for conservation, where the degree of variability in the peat, gravel and chalk geology has clouded hydrological understanding. Notably, a weathered layer on the chalk aquifer surface seals it from overlying deposits, yet is highly spatially heterogeneous. Long-term monitoring yielded observations of groundwater and surface water levels for model calibration and validation. Simulated results were consistent with observed data and reproduced the effects of seasonal fluctuations and in-channel macrophyte growth. The adjacent river and subsidiary channel were found to act as head boundaries, exerting a general control on water levels across the site. Discrete areas of groundwater upwellings caused raised water levels at distinct locations within the wetland. These were concurrent to regions where the weathered chalk layer is absent. To assess impacts of climate change, outputs from the UK Climate Projections 2009 ensemble of global climate models for the 2080s are used to obtain monthly percentage changes in climate variables. Changes in groundwater levels were taken from a regional model of the Chalk aquifer. Values of precipitation and evapotranspiration were seen to increase, whilst groundwater levels decreased, resulting in the greater dominance of precipitation. The discrete areas of groundwater upwelling were seen to diminish or disappear. Simulated water levels were linked to specific requirements of wetland plants using water table depth zone diagrams. Increasing depth of winter and summer groundwater levels leads to a loss of Glyceria maxima and Phragmites

The Compatibility of Geothermal Power Plants with Groundwater Dependent Ecosystems: The Case of the Cesine Wetland (Southern Italy

Directory of Open Access Journals (Sweden)

Giorgio De Giorgio

2018-01-01

Full Text Available The Cesine Wetland, located along the Adriatic coast, was recognized as a Wetland of International Interest and a National Natural Park. Managed by the “World Wide Fund for nature” (WWF, it is considered a groundwater dependent ecosystem which is affected by seawater intrusion. The site was selected to test the environmental compatibility of a low-enthalpy geothermal power plant (closed loop operating in the aquifer saturated portion with purpose to improving the visitor centre. For this purpose, the long-lasting thermal impact on groundwater was assessed using a multi-methodological approach. The complex aquifer system was carefully studied with geological, hydrogeological and geochemical surveys, including chemical and isotopic laboratory analyses of surface water, groundwater and seawater. The isotopes δ18O, δD, δ11B, and 3H were useful to clarify the recharge contribution, the water mixing and the water age. All information was used to improve the conceptualization of the water system, including aquifers and the boundary conditions for a density driven numerical groundwater model. The purpose was to forecast anthropogenic thermal groundwater variations up to 10 years of plant working before the plant realization and to validate the solution after some working years. All results show the environmental compatibility notwithstanding the peculiar ecological environment.

Are isolated wetlands groundwater recharge hotspots?

Science.gov (United States)

Webb, A.; Wicks, C. M.; Brantley, S. T.; Golladay, S. W.

2017-12-01

Geographically isolated wetlands (GIWs) are a common landscape feature in the mantled karst terrain of the Dougherty Plain physiographic district in Southwestern Georgia. These wetlands support a high diversity of obligate/facultative wetland flora and fauna, including several endangered species. While the ecological value of these wetlands is well documented, the hydrologic effects of GIWs on larger watershed processes, such as water storage and aquifer recharge, are less clear. Our project seeks to understand the spatial and temporal variation in recharge across GIWs on this mantled karst landscape. In particular, our first step is to understand the role of isolated wetlands (presumed sinkholes) in delivering water into the underlying aquifer. Our hypothesis is that many GIWs are actually water-filled sinkholes and are locations of focused recharge feeding either the underlying upper Floridan aquifer or the nearby creeks. If we are correct, then these sinkholes should exhibit "drains", i.e., conduits into the limestone bedrock. Thus, the purposes of our initial study are to image the soil-limestone contact (the buried epikarstic surface) and determine if possible subsurface drains exist. Our field work was conducted at the Joseph W Jones Ecological Research Center. During the dry season, we conducted ground penetrating radar (GPR) surveys as grids and lines across a large wetland and across a field with no surface expression of a wetland or sinkhole. We used GPR (200 MHz antenna) with 1-m spacing between antenna and a ping rate of 1 ping per 40 centimeters. Our results show that the epikarstic surface exhibits a drain underneath the wetland (sinkhole) and that no similar feature was seen under the field, even though the survey grid and spacing were similar. As our project progresses, we will survey additional wetlands occurring across varying soil types to determine the spatial distribution between surface wetlands and subsurface drains.

Iron oxides stimulate microbial monochlorobenzene in situ transformation in constructed wetlands and laboratory systems

International Nuclear Information System (INIS)

Schmidt, Marie; Wolfram, Diana; Birkigt, Jan; Ahlheim, Jörg; Paschke, Heidrun; Richnow, Hans-Hermann; Nijenhuis, Ivonne

2014-01-01

Natural wetlands are transition zones between anoxic ground and oxic surface water which may enhance the (bio)transformation potential for recalcitrant chloro-organic contaminants due to the unique geochemical conditions and gradients. Monochlorobenzene (MCB) is a frequently detected groundwater contaminant which is toxic and was thought to be persistent under anoxic conditions. Furthermore, to date, no degradation pathways for anoxic MCB removal have been proven in the field. Hence, it is important to investigate MCB biodegradation in the environment, as groundwater is an important drinking water source in many European countries. Therefore, two pilot-scale horizontal subsurface-flow constructed wetlands, planted and unplanted, were used to investigate the processes in situ contributing to the biotransformation of MCB in these gradient systems. The wetlands were fed with anoxic MCB-contaminated groundwater from a nearby aquifer in Bitterfeld, Germany. An overall MCB removal was observed in both wetlands, whereas just 10% of the original MCB inflow concentration was detected in the ponds. In particular in the gravel bed of the planted wetland, MCB removal was highest in summer season with 73 ± 9% compared to the unplanted one with 40 ± 5%. Whereas the MCB concentrations rapidly decreased in the transition zone of unplanted gravel to the pond, a significant MCB removal was already determined in the anoxic gravel bed of the planted system. The investigation of hydro-geochemical parameters revealed that iron and sulphate reduction were relevant redox processes in both wetlands. In parallel, the addition of ferric iron or nitrate stimulated the mineralisation of MCB in laboratory microcosms with anoxic groundwater from the same source, indicating that the potential for anaerobic microbial degradation of MCB is present at the field site. - Highlights: • MCB removal in anoxic gravel bed of a planted and an unplanted constructed wetland was accompanied by iron

Iron oxides stimulate microbial monochlorobenzene in situ transformation in constructed wetlands and laboratory systems

Energy Technology Data Exchange (ETDEWEB)

Schmidt, Marie; Wolfram, Diana; Birkigt, Jan [Department of Isotope Biogeochemistry, Helmholtz Centre for Environmental Research — UFZ, Permoserstrasse 15, 04318 Leipzig (Germany); Ahlheim, Jörg [Department of Groundwater Remediation, Helmholtz Centre for Environmental Research — UFZ, Permoserstrasse 15, 04318 Leipzig (Germany); Paschke, Heidrun [Department of Analytical Chemistry, Helmholtz Centre for Environmental Research — UFZ, Permoserstrasse 15, 04318 Leipzig (Germany); Richnow, Hans-Hermann [Department of Isotope Biogeochemistry, Helmholtz Centre for Environmental Research — UFZ, Permoserstrasse 15, 04318 Leipzig (Germany); Nijenhuis, Ivonne, E-mail: ivonne.nijenhuis@ufz.de [Department of Isotope Biogeochemistry, Helmholtz Centre for Environmental Research — UFZ, Permoserstrasse 15, 04318 Leipzig (Germany)

2014-02-01

Natural wetlands are transition zones between anoxic ground and oxic surface water which may enhance the (bio)transformation potential for recalcitrant chloro-organic contaminants due to the unique geochemical conditions and gradients. Monochlorobenzene (MCB) is a frequently detected groundwater contaminant which is toxic and was thought to be persistent under anoxic conditions. Furthermore, to date, no degradation pathways for anoxic MCB removal have been proven in the field. Hence, it is important to investigate MCB biodegradation in the environment, as groundwater is an important drinking water source in many European countries. Therefore, two pilot-scale horizontal subsurface-flow constructed wetlands, planted and unplanted, were used to investigate the processes in situ contributing to the biotransformation of MCB in these gradient systems. The wetlands were fed with anoxic MCB-contaminated groundwater from a nearby aquifer in Bitterfeld, Germany. An overall MCB removal was observed in both wetlands, whereas just 10% of the original MCB inflow concentration was detected in the ponds. In particular in the gravel bed of the planted wetland, MCB removal was highest in summer season with 73 ± 9% compared to the unplanted one with 40 ± 5%. Whereas the MCB concentrations rapidly decreased in the transition zone of unplanted gravel to the pond, a significant MCB removal was already determined in the anoxic gravel bed of the planted system. The investigation of hydro-geochemical parameters revealed that iron and sulphate reduction were relevant redox processes in both wetlands. In parallel, the addition of ferric iron or nitrate stimulated the mineralisation of MCB in laboratory microcosms with anoxic groundwater from the same source, indicating that the potential for anaerobic microbial degradation of MCB is present at the field site. - Highlights: • MCB removal in anoxic gravel bed of a planted and an unplanted constructed wetland was accompanied by iron

Preliminary Analysis of the Role of Wetlands and Rivers in the Groundwater Discharge of the Guarani Aquifer System in NE Argentina

International Nuclear Information System (INIS)

Vives, L.; Rodriguez, L.; Manzano, M.; Valladares, A.; Agarwaal, P.; Araguas, L.

2011-01-01

The Guarani Aquifer System (GAS) is a transboundary aquifer occupying parts of Brazil, Uruguay, Paraguay and Argentina, covering some 1200000 km''2. The location and magnitude of recharge and the magnitude of regional discharges are uncertain. Regional groundwater flow modeling suggests that some discharge may occur through selected reaches of the Parana and Uruguay rivers and their tributaries, and perhaps, through the Ibera wetland system within Argentina. Preliminary findings of hydrochemical and isotopic sampling and analysis from surface water and groundwater in the Southern GAS region, studying the role of rivers and wetlands in the aquifer discharge and revising the conceptual model, are presented.

Wetland Surface Water Processes

National Research Council Canada - National Science Library

1993-01-01

.... Temporary storage includes channel, overbank, basin, and groundwater storage. Water is removed from the wetland through evaporation, plant transpiration, channel, overland and tidal flow, and groundwater recharge...

Engineered wetlands for on-site groundwater remediation

International Nuclear Information System (INIS)

Wallace, S.; Davis, B.M.

2008-01-01

Engineered wetlands have been touted as an emerging technology for the in situ remediation of hydrocarbon-contaminated soil and water. They incorporate a horizontal subsurface flow gravel bed reactor lined with impermeable liners, and are equipped with forced bed aeration systems that enhance oxygen delivery to the wetland's aerobic micro-organisms. Engineered wetlands generally emphasize specific characteristics of wetland ecosystems to improve treatment capacities. Design parameters include biodegradation rate coefficients, flowrate, hydraulic residence time plus influent and required effluent concentrations. This paper described the installation of an engineered wetland system at a former British Petroleum (BP) refinery in Wyoming where a pipeline terminal generated contact wastewater containing benzene, toluene, ethylbenzene and xylene (BTEX) and ammonia. The wetland treatment system was designed to treat 6000 m 3 of contaminated ground water per day and has been in operation since May 2003. It was concluded that engineered wetlands can offer long-term solutions to site remediation challenges. 16 refs., 3 tabs., 6 figs

Demonstrating practical application of soil and groundwater clean-up and recovery technologies at natural gas processing facilities: Bioventing, air sparging and wetlands remediation

International Nuclear Information System (INIS)

Moore, B.

1996-01-01

This issue of the project newsletter described the nature of bioventing, air sparging and wetland remediation. It reviewed their effectiveness in remediating hydrocarbon contaminated soil above the groundwater surface. Bioventing was described as an effective, low cost treatment in which air is pumped below ground to stimulate indigenous bacteria. The bacteria then use the oxygen to consume the hydrocarbons, converting them to CO 2 and water. Air sparging involves the injection of air below the groundwater surface. As the air rises, hydrocarbons are stripped from the contaminated soil and water. The advantage of air sparging is that it cleans contaminated soil and water from below the groundwater surface. Hydrocarbon contamination of wetlands was described as fairly common. Conventional remediation methods of excavation, trenching, and bellholes to remove contamination often cause extreme harm to the ecosystem. Recent experimental evidence suggests that wetlands may be capable of attenuating contaminated water through natural processes. Four hydrocarbon contaminated wetlands in Alberta are currently under study. Results to date show that peat's high organic content promotes sorption and biodegradation and that some crude oil spills can been resolved by natural processes. It was suggested that assuming peat is present, a good clean-up approach may be to contain the contaminant source, monitor the lateral and vertical extent of contamination, and wait for natural processes to resolve the problem. 3 figs

Wetland Hydrology | Science Inventory | US EPA

Science.gov (United States)

This chapter discusses the state of the science in wetland hydrology by touching upon the major hydraulic and hydrologic processes in these complex ecosystems, their measurement/estimation techniques, and modeling methods. It starts with the definition of wetlands, their benefits and types, and explains the role and importance of hydrology on wetland functioning. The chapter continues with the description of wetland hydrologic terms and related estimation and modeling techniques. The chapter provides a quick but valuable information regarding hydraulics of surface and subsurface flow, groundwater seepage/discharge, and modeling groundwater/surface water interactions in wetlands. Because of the aggregated effects of the wetlands at larger scales and their ecosystem services, wetland hydrology at the watershed scale is also discussed in which we elaborate on the proficiencies of some of the well-known watershed models in modeling wetland hydrology. This chapter can serve as a useful reference for eco-hydrologists, wetland researchers and decision makers as well as watershed hydrology modelers. In this chapter, the importance of hydrology for wetlands and their functional role are discussed. Wetland hydrologic terms and the major components of water budget in wetlands and how they can be estimated/modeled are also presented. Although this chapter does not provide a comprehensive coverage of wetland hydrology, it provides a quick understanding of the basic co

The origin and disappearance of the late Pleistocene-early Holocene short-lived coastal wetlands along the Carmel coast, Israel

Science.gov (United States)

Sivan, Dorit; Greenbaum, Noam; Cohen-Seffer, Ronit; Sisma-Ventura, Guy; Almogi-Labin, Ahuva

The formation of short-lived backswamps along the Carmel coast of Israel coincides with the rapid global sea-level rise during the late Pleistocene-early Holocene transition. The current study shows that the wetland phenomena originated around 10,000 yr ago and dried up shortly before the local Pre-Pottery Neolithic humans settled on the wetland dark clay sediments 9430 cal yr BP. Palaeontological and stable-isotope data were used in this study to elucidate previously published sedimentological reconstruction obtained from a core drilled into the western trough of the Carmel coastal plain. The water body contained typical brackish calcareous fauna, with variable numerical abundance and low species richness of ostracods and foraminifera. The δ 18O and δ 13C of the ostracod Cyprideis torosa show close similarity to the present Pleistocene coastal aquifer isotopic values. This study therefore concludes that the wetlands were shallow-water bodies fed by groundwater, with no evidence of sea-water mixing. It seems that they developed as the result of high groundwater levels, transportation of sediments landward, and deposition of sand bars at the paleo-river mouths. It is still not fully understood why these wetlands deteriorated abruptly and disappeared within less than 1000 yr.

Model of hydrological behaviour of the anthropized semiarid wetland of Las Tablas de Daimiel National Park (Spain) based on surface water-groundwater interactions

Science.gov (United States)

Aguilera, H.; Castaño, S.; Moreno, L.; Jiménez-Hernández, M. E.; de la Losa, A.

2013-05-01

Las Tablas de Daimiel National Park (TDNP) in Spain is one of the most important semiarid wetlands of the Mediterranean area. The inversion of the regional groundwater flow, primarily due to overexploitation and inadequate aquifer management, has led to degradation. The system has turned from a groundwater discharge zone into a recharge zone, and has remained mostly dry since the 1980s. High heterogeneity and complexity, enhanced by anthropogenic management action, hampers prediction of the surface-groundwater system response to flooding events. This study analyses these interactions and provides empirical evidence to define a conceptual model of flooding-infiltration-groundwater dynamics through the application of a few simple analysis tools to basic hydrological data. Relevant surface water-groundwater interactions are mainly localized in the left (west) margin of TDNP, as confirmed by the fast responses to flooding observed in the hydrochemic, hydrodynamic and isotopic data. During drying periods, small artificial and/or low-flow natural floods are followed by infiltration of evaporated poor-quality ponding water into saline low-permeability layers. The results allow an improved understanding of the hydrological behaviour essential to support efficient management practices. The relative simplicity of the methodology allows for its application in other similar complex groundwater-linked wetlands where detailed knowledge of local geology is still absent.

Groundwater in the hydrological functioning of wetlands in the Southeast of Buenos Aires Province, Argentina

International Nuclear Information System (INIS)

Romanelli, A.; Quiroz, O.M.; Massone, H.E.; Martinez, D.E.; Bocanegra, E.

2010-01-01

The understanding of the hydrological functioning and the interaction among the different water bodies in an area is essential when a sustainable use of the hydric resources is considered. The hydrogeochemical interpretation of representative water-sample analyses is a useful tool developed for the analysis of hydrological systems. Isotopic techniques are also important tools for the validation and adjustment of conceptual hydrogeological models. The aim of the present paper is to develop depth of knowledge of the conceptual hydrogeological models for wetlands of the Pampa Plain by using hydrochemical and stable isotopic techniques. Three wetlands of different origin were sampled for hydrochemical and stable isotopic analysis (18O and 2H) at different depths. Groundwater and streams were also sampled. Hydrochemical analysis classified La Brava and Los Padres basins as sodium bicarbonate waters, and La Salada Basin as sodium chloride bicarbonate waters. Differences in the isotopic fingerprints and the electrical conductivity values were evident among wetlands: 6.766,8, 762,2 y 647,8 iS/cm in La Salada, Los Padres and La Brava respectively. Hydrochemical and isotopic data allowed us to define the effluent-influent behavior of these wetlands, their main recharge sources and their importance as aquifer recharge areas. (Author).

Groundwater-surface water interaction

International Nuclear Information System (INIS)

White, P.A.; Clausen, B.; Hunt, B.; Cameron, S.; Weir, J.J.

2001-01-01

This chapter discusses natural and modified interactions between groundwater and surface water. Theory on recharge to groundwater from rivers is introduced, and the relative importance of groundwater recharge from rivers is illustrated with an example from the Ngaruroro River, Hawke's Bay. Some of the techniques used to identify and measure recharge to groundwater from gravel-bed rivers will be outlined, with examples from the Ngaruroro River, where the recharge reach is relatively well defined, and from the Rakaia River, where it is poorly defined. Groundwater recharged from rivers can have characteristic chemical and isotopic signatures, as shown by Waimakariri River water in the Christchurch-West Melton groundwater system. The incorporation of groundwater-river interaction in a regional groundwater flow model is outlined for the Waimea Plains, and relationships between river scour and groundwater recharge are examined for the Waimakariri River. Springs are the result of natural discharge from groundwater systems and are important water sources. The interactions between groundwater systems, springs, and river flow for the Avon River in New Zealand will be outlined. The theory of depletion of stream flow by groundwater pumpage will be introduced with a case study from Canterbury, and salt-water intrusion into groundwater systems with examples from Nelson and Christchurch. The theory of artificial recharge to groundwater systems is introduced with a case study from Hawke's Bay. Wetlands are important to flora, and the relationship of the wetland environment to groundwater hydrology will be discussed, with an example from the South Taupo wetland. (author). 56 refs., 25 figs., 3 tabs

Effects of groundwater pumping on the sustainability of a mountain wetland complex, Yosemite National Park, California

Directory of Open Access Journals (Sweden)

David J. Cooper

2015-03-01

Full Text Available Study Region: We analyzed the effects of groundwater pumping on a mountain wetland complex, Yosemite National Park, California, USA. Study Focus: Groundwater pumping from mountain meadows is common in many regions of the world. However, few quantitative analyses exist of the hydrologic or ecological effects of pumping. New Hydrological Insights for the Region: Daily hydraulic head and water table variations at sampling locations within 100 m of the pumping well were strongly correlated with the timing and duration of pumping. The effect of pumping varied by distance from the pumping well, depth of the water table when the pumping started, and that water year's snow water equivalent (SWE. Pumping in years with below average SWE and/or early melting snow pack, resulted in a water table decline to the base of the fen peat body by mid summer. Pumping in years with higher SWE and later melting snowpack, resulted in much less water level drawdown from the same pumping schedule. Predictive modeling scenarios showed that, even in a dry water year like 2004, distinct increases in fen water table elevation can be achieved with reductions in pumping. A high water table during summers following low snowpack water years had a more significant influence on vegetation composition than depth of water table in wet years or peat thickness, highlighting the impact of water level drawdown on vegetation. Keywords: Fen, Groundwater pumping, Modeling, Mountain meadow, Water table, Wetlands

Regional paleohydrologic and paleoclimatic settings of wetland/lacustrine depositional systems in the Morrison Formation (Upper Jurassic), Western Interior, USA

Science.gov (United States)

Dunagan, S.P.; Turner, C.E.

2004-01-01

and shoreline deposits. Marginal lacustrine deposits include ooid and skeletal packstone-grainstone, siltstone, and sandstone. Distal lacustrine units are skeletal mudstone-wackestone, microbialites, and laminated (siliciclastic) mudstone. Differentiation between wetlands and distal lacustrine units is not always possible. Palustrine features, Magadi-type chert (MTC), and evaporites record episodes of increased aridity and exposure. Farther upstream, during deposition of the upper part of the Brushy Basin Member, the ancestral Uncompahgre Uplift imposed a barrier to shallow, eastward-flowing groundwater that discharged into the San Juan/Paradox Basin on the upstream side of the uplift. This created the closed hydrologic setting necessary for development of an alkaline-saline wetland/lacustrine complex ("Lake" T'oo'dichi'). Silicic volcanic ash, delivered by prevailing winds from calderas west and southwest of the basin, contributed to the pore-water evolution in the sediments. A distinctive lateral hydrogeochemical gradient, reflecting increasing salinity and alkalinity in the pore waters, altered the ash to a variety of authigenic minerals that define concentric zones within the basin. The basinward progression of diagenetic mineral zones is smectite???clinoptilolite???analcime ??potassium feldspar???albite. The groundwater-fed wetlands were shallow and frequently evaporated to dryness. Scarce laminated gray mudstone beds record distinct episodes of freshwater lacustrine deposition that resulted from intermittent streams that carried detritus well out into the basin. ?? 2004 Elsevier B.V. All rights reserved.

Nitrate movement and removal along a shallow groundwater flow path in a riparian wetland within a sheep-grazed pastoral catchment : result of a tracer study

International Nuclear Information System (INIS)

Burns, D.A.; Nguyen, L.

2002-01-01

The movement and removal of nitrate (NO 3 ) along a groundwater flow path within a riparian wetland was investigated during a 24-day period in late autumn-early winter, using a lithium bromide (LiBr)-potassium nitrate (KNO 3 ) tracer solution containing 19 200 mg/litre as Br - and 193.8 mg/litre as NO 3 -N. The tracer solution was added as an instantaneous dose of tracer solution at a depth of 10-20 cm to four injection wells in two 1 m 2 plots within a sheep-grazed pastoral catchment at the Whatawhata Agricultural Research Centre near Hamilton, New Zealand. Bromide and NO 3- N concentrations were measured periodically in: (1) wetland groundwater samples from piezometers installed at 15 and 30 cm depths and located at 30, 60, and 100 cm down gradient from the injection wells; and (2) surface flow samples. Peak concentrations of 50-250 mg/litre of Br - and 0.2-1.1 mg/litre of NO 3 -N were reached within 1-2 days after application at most piezometers. Nitrate concentrations decreased thereafter more sharply than did those of Br - , resulting in decreased NO 3 -N/Br - ratios from Days 2 through 7. More than 99% of groundwater samples collected after the tracer application had NO 3 -N/Br - less than the value in the tracer solution indicating removal of NO 3 -N during transport. Mass flux estimates indicated removal of >90% of added NO 3 -N along the 100 cm flow path from the injection, with essentially all of the NO 3 - removed within the first 30 cm of transport. On Days 10 and 24, just after rain events, surface flow from the experimental plots had greatly elevated NO 3 -N concentrations that were not accompanied by correspondingly elevated Br - concentrations, indicating that NO 3 -N originating from the surrounding catchment was transported over the wetland surface with little penetration or mixing with wetland groundwater. Despite a significant capacity for NO 3 -N removal from shallow groundwater equivalent to an annualised value of 50 kg/ha in these wetland

Understanding wetland sub-surface hydrology using geologic and isotopic signatures

Directory of Open Access Journals (Sweden)

P. Sahu

2009-07-01

Full Text Available This paper attempts to utilize hydrogeology and isotope composition of groundwater to understand the present hydrological processes prevalent in a freshwater wetland, source of wetland groundwater, surface water/groundwater interaction and mixing of groundwater of various depth zones in the aquifer. This study considers East Calcutta Wetlands (ECW – a freshwater peri-urban inland wetland ecosystem located at the lower part of the deltaic alluvial plain of South Bengal Basin and east of Kolkata city. This wetland is well known over the world for its resource recovery systems, developed by local people through ages, using wastewater of the city. Geological investigations reveal that the sub-surface geology is completely blanketed by the Quaternary sediments comprising a succession of silty clay, sand of various grades and sand mixed with occasional gravels and thin intercalations of silty clay. At few places the top silty clay layer is absent due to scouring action of past channels. In these areas sand is present throughout the geological column and the areas are vulnerable to groundwater pollution. Groundwater mainly flows from east to west and is being over-extracted to the tune of 65×10³ m³/day. δ¹⁸O and δD values of shallow and deep groundwater are similar indicating resemblance in hydrostratigraphy and climate of the recharge areas. Groundwater originates mainly from monsoonal rain with some evaporation prior to or during infiltration and partly from bottom of ponds, canals and infiltration of groundwater withdrawn for irrigation. Relatively high tritium content of the shallow groundwater indicates local recharge, while the deep groundwater with very low tritium is recharged mainly from distant areas. At places the deep aquifer has relatively high tritium, indicating mixing of groundwater of shallow and deep aquifers. Metals such as copper, lead, arsenic, cadmium, aluminium, nickel and chromium are also

Understanding wetland sub-surface hydrology using geologic and isotopic signatures

Science.gov (United States)

Sikdar, P. K.; Sahu, P.

2009-07-01

This paper attempts to utilize hydrogeology and isotope composition of groundwater to understand the present hydrological processes prevalent in a freshwater wetland, source of wetland groundwater, surface water/groundwater interaction and mixing of groundwater of various depth zones in the aquifer. This study considers East Calcutta Wetlands (ECW) - a freshwater peri-urban inland wetland ecosystem located at the lower part of the deltaic alluvial plain of South Bengal Basin and east of Kolkata city. This wetland is well known over the world for its resource recovery systems, developed by local people through ages, using wastewater of the city. Geological investigations reveal that the sub-surface geology is completely blanketed by the Quaternary sediments comprising a succession of silty clay, sand of various grades and sand mixed with occasional gravels and thin intercalations of silty clay. At few places the top silty clay layer is absent due to scouring action of past channels. In these areas sand is present throughout the geological column and the areas are vulnerable to groundwater pollution. Groundwater mainly flows from east to west and is being over-extracted to the tune of 65×103 m3/day. δ18O and δD values of shallow and deep groundwater are similar indicating resemblance in hydrostratigraphy and climate of the recharge areas. Groundwater originates mainly from monsoonal rain with some evaporation prior to or during infiltration and partly from bottom of ponds, canals and infiltration of groundwater withdrawn for irrigation. Relatively high tritium content of the shallow groundwater indicates local recharge, while the deep groundwater with very low tritium is recharged mainly from distant areas. At places the deep aquifer has relatively high tritium, indicating mixing of groundwater of shallow and deep aquifers. Metals such as copper, lead, arsenic, cadmium, aluminium, nickel and chromium are also present in groundwater of various depths. Therefore

Dissolved organic matter signatures vary between naturally acidic, circumneutral and groundwater-fed freshwaters in Australia.

Science.gov (United States)

Holland, Aleicia; Stauber, Jenny; Wood, Chris M; Trenfield, Melanie; Jolley, Dianne F

2018-06-15

Dissolved organic matter (DOM) plays important roles in both abiotic and biotic processes within aquatic ecosystems, and these in turn depend on the quality of the DOM. We collected and characterized chromophoric DOM (CDOM) from different Australian freshwater types (circumneutral, naturally acidic and groundwater-fed waterways), climatic regions and seasons. CDOM quality was characterized using absorbance and fluorescence spectroscopy. Excitation emission scans followed by parallel factor (PARAFAC) analysis showed that CDOM was characterized by three main components: protein-like, fulvic-like and humic-like components commonly associated with various waters globally in the Openfluor database. Principal component analysis showed that CDOM quality varied between naturally acidic, circumneutral and groundwater-fed waters, with unique CDOM quality signatures shown for each freshwater type. CDOM quality also differed significantly within some sites between seasons. Clear differences in dominant CDOM components were shown between freshwater types. Naturally acidic waters were dominated by highly aromatic (as indicated by the specific absorbance co-efficient (SAC 340 ) and the specific UV absorbance (SUVA 254 ) values which ranged between 31 and 50 cm 2  mg -1 and 3.9-5.7 mg C -1  m -1 respectively), humic-like CDOM of high molecular weight (as indicated by abs 254/365 which ranged from 3.8 to 4.3). In contrast, circumneutral waters were dominated by fulvic-like CDOM of lower aromaticity (SAC 340 : 7-21 cm 2  mg -1 and SUVA 254 : 1.5-3.0 mg C -1  m -1 ) and lower molecular weight (abs 254/365 5.1-9.3). The groundwater-fed site had a higher abundance of protein-like CDOM, which was the least aromatic (SAC 340 : 2-5 cm 2  mg -1 and SUVA 254 : 0.58-1.1 mg C -1  m -1 ). CDOM was generally less aromatic, of a lower molecular weight and more autochthonous in nature during the summer/autumn sampling compared to winter/spring. Significant

Incorporation of GRACE Data into a Bayesian Model for Groundwater Drought Monitoring

Science.gov (United States)

Slinski, K.; Hogue, T. S.; McCray, J. E.; Porter, A.

2015-12-01

Groundwater drought, defined as the sustained occurrence of below average availability of groundwater, is marked by below average water levels in aquifers and reduced flows to groundwater-fed rivers and wetlands. The impact of groundwater drought on ecosystems, agriculture, municipal water supply, and the energy sector is an increasingly important global issue. However, current drought monitors heavily rely on precipitation and vegetative stress indices to characterize the timing, duration, and severity of drought events. The paucity of in situ observations of aquifer levels is a substantial obstacle to the development of systems to monitor groundwater drought in drought-prone areas, particularly in developing countries. Observations from the NASA/German Space Agency's Gravity Recovery and Climate Experiment (GRACE) have been used to estimate changes in groundwater storage over areas with sparse point measurements. This study incorporates GRACE total water storage observations into a Bayesian framework to assess the performance of a probabilistic model for monitoring groundwater drought based on remote sensing data. Overall, it is hoped that these methods will improve global drought preparedness and risk reduction by providing information on groundwater drought necessary to manage its impacts on ecosystems, as well as on the agricultural, municipal, and energy sectors.

A conceptual framework for assessing cumulative impacts on the hydrology of nontidal wetlands

Science.gov (United States)

Winter, Thomas C.

1988-01-01

Wetlands occur in geologic and hydrologic settings that enhance the accumulation or retention of water. Regional slope, local relief, and permeability of the land surface are major controls on the formation of wetlands by surface-water sources. However, these landscape features also have significant control over groundwater flow systems, which commonly play a role in the formation of wetlands. Because the hydrologic system is a continuum, any modification of one component will have an effect on contiguous components. Disturbances commonly affecting the hydrologic system as it relates to wetlands include weather modification, alteration of plant communities, storage of surface water, road construction, drainage of surface water and soil water, alteration of groundwater recharge and discharge areas, and pumping of groundwater. Assessments of the cumulative effects of one or more of these disturbances on the hydrologic system as related to wetlands must take into account uncertainty in the measurements and in the assumptions that are made in hydrologic studies. For example, it may be appropriate to assume that regional groundwater flow systems are recharged in uplands and discharged in lowlands. However, a similar assumption commonly does not apply on a local scale, because of the spatial and temporal dynamics of groundwater recharge. Lack of appreciation of such hydrologic factors can lead to misunderstanding of the hydrologic function of wetlands within various parts of the landscape and mismanagement of wetland ecosystems.

Wetland survey of the X-10 Bethel Valley and Melton Valley groundwater operable units at Oak Ridge National Labortory Oak Ridge, Tennessee

International Nuclear Information System (INIS)

Rosensteel, B.A.

1996-03-01

Executive Order 11990, Protection of Wetlands, (May 24, 1977) requires that federal agencies avoid, to the extent possible, adverse impacts associated with the destruction and modification of wetlands and that they avoid direct and indirect support of wetlands development when there is a practicable alternative. In accordance with Department of Energy (DOE) Regulations for Compliance with Floodplains and Wetlands Environmental Review Requirements (Subpart B, 10 CFR 1022.11), surveys for wetland presence or absence were conducted in both the Melton Valley and the Bethel Valley Groundwater Operable Units (GWOU) on the DOE Oak Ridge Reservation (ORR) from October 1994 through September 1995. As required by the Energy and Water Development Appropriations Act of 1992, wetlands were identified using the criteria and methods set forth in the Wetlands Delineation Manual (Army Corps of Engineers, 1987). Wetlands were identified during field surveys that examined and documented vegetation, soils, and hydrologic evidence. Most of the wetland boundary locations and wetland sizes are approximate. Boundaries of wetlands in Waste Area Grouping (WAG) 2 and on the former proposed site of the Advanced Neutron Source in the upper Melton Branch watershed were located by civil survey during previous wetland surveys; thus, the boundary locations and areal sizes in these areas are accurate. The wetlands were classified according to the system developed by Cowardin et al. (1979) for wetland and deepwater habitats of the United States. A total of 215 individual wetland areas ranging in size from 0.002 ha to 9.97 ha were identified in the Bethel Valley and Melton Valley GWOUs. The wetlands are classified as palustrine forested broad-leaved deciduous (PFO1), palustrine scrub-shrub broad-leaved deciduous (PSS1), and palustrine persistent emergent (PEM1)

Nitrate fate and transport through current and former depressional wetlands in an agricultural landscape, Choptank Watershed, Maryland, United States

Science.gov (United States)

Denver, J.M.; Ator, S.W.; Lang, M.W.; Fisher, T.R.; Gustafson, A.B.; Fox, R.; Clune, J.W.; McCarty, G.W.

2014-01-01

Understanding local groundwater hydrology and geochemistry is critical for evaluating the effectiveness of wetlands at mitigating agricultural impacts on surface waters. The effectiveness of depressional wetlands at mitigating nitrate (NO3) transport from fertilized row crops, through groundwater, to local streams was examined in the watershed of the upper Choptank River, a tributary of Chesapeake Bay on the Atlantic Coastal Plain. Hydrologic, geochemical, and water quality data were collected from January of 2008 through December of 2009 from surface waters and networks of piezometers installed in and around current or former depressional wetlands of three major types along a gradient of anthropogenic alteration: (1) natural wetlands with native vegetation (i.e., forested); (2) prior-converted croplands, which are former wetlands located in cultivated fields; and (3) hydrologically restored wetlands, including one wetland restoration and one shallow water management area. These data were collected to estimate the orientation of groundwater flow paths and likely interactions of groundwater containing NO3 from agricultural sources with reducing conditions associated with wetlands of different types. Natural wetlands were found to have longer periods of soil saturation and reducing conditions conducive to denitrification compared to the other wetland types studied. Because natural wetlands are typically located in groundwater recharge areas along watershed divides, nitrogen (N) from nearby agriculture was not intercepted. However, these wetlands likely improve water quality in adjacent streams via dilution. Soil and geochemical conditions conducive to denitrification were also present in restored wetlands and prior-converted croplands, and substantial losses of agricultural NO3 were observed in groundwater flowing through these wetland sediments. However, delivery of NO3 from agricultural areas through groundwater to these wetlands resulting in opportunities for

Novel Large Sulfur Bacteria in the Metagenomes of Groundwater-Fed Chemosynthetic Microbial Mats in the Lake Huron Basin

OpenAIRE

Allison M. Sharrar; Beverly E. Flood; Jake V. Bailey; Daniel S. Jones; Daniel S. Jones; Bopaiah A. Biddanda; Steven A. Ruberg; Daniel N. Marcus; Gregory J. Dick

2017-01-01

Little is known about large sulfur bacteria (LSB) that inhabit sulfidic groundwater seeps in large lakes. To examine how geochemically relevant microbial metabolisms are partitioned among community members, we conducted metagenomic analysis of a chemosynthetic microbial mat in the Isolated Sinkhole, which is in a deep, aphotic environment of Lake Huron. For comparison, we also analyzed a white mat in an artesian fountain that is fed by groundwater similar to Isolated Sinkhole, but that sits i...

Interaction of hydrological regime and vegetation in a seasonally flooded lake wetland (Poyang Lake) in China

Science.gov (United States)

Zhang, Qi

2017-04-01

Hydrological regime has been widely recognized as one of the major forces determining vegetation distribution in seasonally flooded wetlands. To explore the influences of hydrological conditions on the spatial distribution of wetland vegetation, an experimental transect in Poyang Lake wetland, the largest freshwater lake in China, was selected as a study area. In-situ high time frequency observations of climate, soil moisture, groundwater level and surface water level were simultaneously conducted. Vegetation was sampled periodically to obtain species composition, diversity and biomass. Results show that significant hydrological gradient exists along the experimental transect. Both groundwater level and soil moisture demonstrate high correlation with the distribution of different communities of vegetation. Above- and belowground biomass present Gaussian models along the gradient of groundwater depth in growing seasons. It was found that the optimal average groundwater depths for above- and belowground biomass are 0.8 m and 0.5 m, respectively. Numerical simulations using HYDRUS-1D further indicated that the groundwater depths had significant influences on the water usage by vegetation, which suggested the high dependence of wetland vegetation on groundwater, even in a wet climate zone such as Poyang Lake. The study revealed new knowledge on the interaction of hydrological regime and wetland vegetation, and provided scientific support for an integrated management of balancing wetland ecology and water resources development in Poyang Lake, and other lake floodplain wetlands, with strong human interferences.

Spatial variation in background groundwater geochemistry of the Gurinai Wetland, Gobi Desert, Inner Mongolia

Science.gov (United States)

Gu, Weizu; Peters, N.E.

1995-01-01

Age dating of groundwater from several hand-dug wells in the Gurinai Wetland of the Badajilin-Gobi Desert, north-central China, indicated a continuum from present to 7625??155 years B.P. Water age correlates with concentration for some constituents. In general, concentrations of Fe, Cr, Se and Sr increase with increasing age, whereas Ca, Br, Zn and Rb decrease. Compared to concentration ranges reported for freshwaters, several constituents were much more concentrated including Na, Cl, Mg, Br and Th, and many others extended the upper concentration limit including Sr, Mo, Rb, Cr, U, Se, Nb and Ce. For Th, the maximum observed concentration extends the previously summarized maximum by more than an order of magnitude.

Hydrologic response in karstic-ridge wetlands to rainfall and evapotranspiration, central Florida, 2001-2003

Science.gov (United States)

Knowles, Leel; Phelps, G.G.; Kinnaman, Sandra L.; German, Edward R.

2005-01-01

Two internally drained karstic wetlands in central Florida-Boggy Marsh at the Hilochee Wildlife Management Area and a large unnamed wetland at the Lyonia Preserve-were studied during 2001-03 to gain a better understanding of the net-recharge function that these wetlands provide, the significance of exchanges with ground water with regard to wetland water budgets, and the variability in wetland hydrologic response to a range of climate conditions. These natural, relatively remote and unaltered wetlands were selected to provide a baseline of natural wetland hydrologic variability to which anthropogenic influences on wetland hydrology could be compared. Large departures from normal rainfall during the study were fortuitous, and allowed monitoring of hydrologic processes over a wide range of climate conditions. Wetland responses varied greatly as a result of climate conditions that ranged from moderate drought to extremely moist. Anthropogenic activities influenced water levels at both study sites; however, because these activities were brief relative to the duration of the study, sufficient data were collected during unimpacted periods to allow for the following conclusions to be made. Water budgets developed for Boggy Marsh and the Lyonia large wetland showed strong similarity between the flux terms of rainfall, evaporation, net change in storage, and the net ground-water exchange residual. Runoff was assumed to be negligible. Of the total annual flux at Boggy Marsh, rainfall accounted for 45 percent; evaporation accounted for 25 percent; net change in storage accounted for 25 percent; and the net residual accounted for 5 percent. At the Lyonia large wetland, rainfall accounted for 44 percent; evaporation accounted for 29 percent; net change in storage accounted for 21 percent; and the net residual accounted for 6 percent of the total annual flux. Wetland storage and ground-water exchange were important when compared to the total water budget at both wetlands. Even

Observations On Some Upper Amazonian Wetlands of Southeastern Peru

Science.gov (United States)

Householder, J. E.; Muttiah, R.; Khanal, S.

2007-05-01

Upper Amazonian wetlands represent little studied, poorly understood, and grossly under protected systems. Scientific investigation of Amazonian wetlands is in its infancy; nor is there much known about their ecological services. Regionally, wetlands form a ubiquitous and significant component of floodplain habitat fed by perennial springs as well as overland runoff. Locally, wetland vegetation forms bewilderingly complex vegetation mosaics that seem to be governed by local topography and hydrology. Drawing upon intensive field campaigns and remotely sensed imagery, we summarize the results and experiences gathered in wetlands of southeastern Peru.

Effects of influent strength on microorganisms in surface flow mesocosm wetlands.

Science.gov (United States)

Tao, Wendong; Hall, Ken J; Ramey, William

2007-11-01

To choose an appropriate dilution ratio to treat woodwaste leachate without inhibition on heterotrophic bacteria, microbial ATP concentration and the rates of heterotrophic leucine incorporation and acetate uptake were compared across surface flow mesocosm wetlands fed with different strengths of influent. Abundances of protozoa and respiring bacteria were investigated in two mesocosm wetlands to elucidate the effects of influent strength on heterotrophic bacteria. The strongest influent or the raw leachate did not show a significant inhibitory effect on leucine incorporation and acetate uptake. Instead, leucine incorporation rates by bacteria in water, epiphytic biofilm and sediment were higher in mesocosm wetlands fed with a stronger influent. There were significantly more respiring planktonic bacteria (451 x 10(5) mL(-1)) and fewer nanoflagellates (3.8 x 10(3) mL(-1)) in the mesocosm fed with a strong influent, while fewer respiring planktonic bacteria (38.7 x 10(5)mL(-1)) and more nanoflagellates (15.4 x 10(3) mL(-1)) in the mesocosm fed with a weak influent. The majority of the total microbial ATP was attributed to sedimentary bacteria, of which >96% were inactive. Heterotrophic activity and its distribution among water, epiphytic biofilm and sediment in the mesocosm wetlands were affected by availability of bacterial substrates and grazing pressure of nanoflagellates.

Climatic Controls on the Porewater Chemistry of Mid-Continental Wetlands

Science.gov (United States)

Levy, Zeno Francis

Wetlands develop where climate and physiography conspire to maintain saturated soils at the land surface, support diverse plant and animal communities, and serve as globally important sinks for atmospheric carbon. The chemistry of wetland porewaters impacts near-surface biological communities and subsurface biogeochemical processes that influence carbon cycling in the environment. Wetland porewater chemistry is a dynamic byproduct of complex hydrogeological processes that cause meteoric waters to enter groundwater systems (recharge) or groundwater to flow to the land surface (discharge). Changes in climate can alter subsurface hydraulic gradients that determine the recharge and discharge functions of wetlands, which in turn control the hydrogeochemical evolution of wetland porewaters. The climate of mid-continental North America is influenced by competing air masses with vastly different temperature and moisture contents originating from the Pacific Coast, the Gulf of Mexico, and the Arctic. The interactions of these air masses result in large dynamic shifts of climate regimes characterized by decadal-scale oscillations between periods of drought and heavy rain. Over the course of the 20th century, a shift occurred towards wetter climate in the mid-continental region. This dissertation examines the impact of this climate shift on the porewater chemistry of two very different wetland systems, located only 350 km apart: the Glacial Lake Agassiz Peatlands (GLAP) of northern Minnesota and the Cottonwood Lake Study Area (CLSA) of North Dakota. The former study site consists of a large (7,600 km2), circumboreal peatland that developed an extensive blanket of peat over the last 5000 years on a relatively flat glacial lake bed within a sub-humid to semi-arid climate gradient characterized by small annual atmospheric moisture surpluses and frequent droughts. The latter study site consists of a 0.92 km2 complex of small (meter-scale) "prairie pothole" wetlands located on a

Investigating Hydrogeologic Controls on Sandhill Wetlands in Covered Karst with 2D Resistivity and Ground Penetrating Radar

Science.gov (United States)

Downs, C. M.; Nowicki, R. S.; Rains, M. C.; Kruse, S.

2015-12-01

In west-central Florida, wetland and lake distribution is strongly controlled by karst landforms. Sandhill wetlands and lakes are sand-filled upland basins whose water levels are groundwater driven. Lake dimensions only reach wetland edges during extreme precipitation events. Current wetland classification schemes are inappropriate for identifying sandhill wetlands due to their unique hydrologic regime and ecologic expression. As a result, it is difficult to determine whether or not a wetland is impacted by groundwater pumping, development, and climate change. A better understanding of subsurface structures and how they control the hydrologic regime is necessary for development of an identification and monitoring protocol. Long-term studies record vegetation diversity and distribution, shallow ground water levels and surface water levels. The overall goals are to determine the hydrologic controls (groundwater, seepage, surface water inputs). Most recently a series of geophysical surveys was conducted at select sites in Hernando and Pasco County, Florida. Electrical resistivity and ground penetrating radar were employed to image sand-filled basins and the top of the limestone bedrock and stratigraphy of wetland slopes, respectively. The deepest extent of these sand-filled basins is generally reflected in topography as shallow depressions. Resistivity along inundated wetlands suggests the pools are surface expressions of the surficial aquifer. However, possible breaches in confining clay layers beneath topographic highs between depressions are seen in resistivity profiles as conductive anomalies and in GPR as interruptions in otherwise continuous horizons. These data occur at sites where unconfined and confined water levels are in agreement, suggesting communication between shallow and deep groundwater. Wetland plants are observed outside the historic wetland boundary at many sites, GPR profiles show near-surface layers dipping towards the wetlands at a shallower

Constructed wetlands for treatment of dissolved phase hydrocarbons

Energy Technology Data Exchange (ETDEWEB)

Moore, B J; Ross, S D [Komex International, Calgary, AB (Canada); Gibson, D [Calgary Univ., AB (Canada); Hardisty, P E [Komex Clarke Bond, Bristol (United Kingdom)

1999-01-01

The use of constructed wetlands as an alternative to conventional treatment of condensate-contaminated groundwater was studied. In 1997 a pilot scale wetland was constructed and implemented at the Gulf Strachan Gas Processing Plant to determine its ability in treating extracted groundwater contaminated with natural gas condensates. This paper presented the results of hydrocarbon removal efficiency, hydrocarbon removal mechanisms, winter operation, and the effect of hydrocarbons on vegetation health. The inflow water to the wetland contains 15 to 20 mg/L of C[sub 5]-C[sub 10] hydrocarbons, including 50 per cent BTEX compounds. During the summer months, hydrocarbon removal efficiency was 100 per cent, but decreased to 60 and 30 per cent in the spring and late fall, respectively. The hydrocarbons not removed in the wetland were eventually removed along the outflow channel. Temperature was determined to be an important factor in the variable removal rates, particularly when there is no aeration. The main hydrocarbon removal mechanisms appear to be volatilization, biodegradation and dilution. At present, plant uptake is not a factor. 12 refs., 1 tab., 3 figs.

Constructed wetlands for treatment of dissolved phase hydrocarbons

International Nuclear Information System (INIS)

Moore, B.J.; Ross, S.D.; Gibson, D.; Hardisty, P.E.

1999-01-01

The use of constructed wetlands as an alternative to conventional treatment of condensate-contaminated groundwater was studied. In 1997 a pilot scale wetland was constructed and implemented at the Gulf Strachan Gas Processing Plant to determine its ability in treating extracted groundwater contaminated with natural gas condensates. This paper presented the results of hydrocarbon removal efficiency, hydrocarbon removal mechanisms, winter operation, and the effect of hydrocarbons on vegetation health. The inflow water to the wetland contains 15 to 20 mg/L of C 5 -C 10 hydrocarbons, including 50 per cent BTEX compounds. During the summer months, hydrocarbon removal efficiency was 100 per cent, but decreased to 60 and 30 per cent in the spring and late fall, respectively. The hydrocarbons not removed in the wetland were eventually removed along the outflow channel. Temperature was determined to be an important factor in the variable removal rates, particularly when there is no aeration. The main hydrocarbon removal mechanisms appear to be volatilization, biodegradation and dilution. At present, plant uptake is not a factor. 12 refs., 1 tab., 3 figs

Uranium Immobilization in Wetland Soils

Science.gov (United States)

Jaffe, Peter R.; Koster van Groos, Paul G.; Li, Dien; Chang, Hyun-Shik; Seaman, John C.; Kaplan, Daniel I.; Peacock, Aaron D.; Scheckel, Kirk

2014-05-01

In wetlands, which are a major feature at the groundwater-surface water interface, plants deliver oxygen to the subsurface to keep root tissue aerobic. Some of this oxygen leaches into the rhizosphere where it will oxidize iron that typically precipitates on or near roots. Furthermore, plans provide carbon via root exudates and turnover, which in the presence of the iron oxides drives the activity of heterotrophic iron reducers in wetland soils. Oxidized iron is an important electron acceptor for many microbially-driven transformations, which can affect the fate and transport of several pollutants. It has been shown that heterotrophic iron reducing organisms, such as Geobacter sp., can reduce water soluble U(VI) to insoluble U(IV). The goal of this study was to determine if and how iron cycling in the wetland rhizosphere affects uranium dynamics. For this purpose, we operated a series of small-scale wetland mesocosms in a greenhouse to simulate the discharge of uranium-contaminated groundwater to surface waters. The mesocosms were operated with two different Fe(II) loading rates, two plant types, and unplanted controls. The mesocosms contained zones of root exclusion to differentiate between the direct presence and absence of roots in the planted mesocosms. The mesocosms were operated for several month to get fully established, after which a U(VI) solution was fed for 80 days. The mesocosms were then sacrificed and analyzed for solid-associated chemical species, microbiological characterization, micro-X-ray florescence (µ-XRF) mapping of Fe and U on the root surface, and U speciation via X-ray Absorption Near Edge Structure (XANES). Results showed that bacterial numbers including Geobacter sp., Fe(III), as well as total uranium, were highest on roots, followed by sediments near roots, and lowest in zones without much root influence. Results from the µ-XRF mapping on root surfaces indicated a strong spatial correlation between Fe and U. This correlation was

The hydrodynamic response of a semi-arid headwater wetland to ...

African Journals Online (AJOL)

This paper presents findings of a hydrological monitoring study of the shallow groundwaters to determine the wetland's hydrodynamic behaviour and the extent to which this had degraded as a result of erosion. Furthermore, whether technical rehabilitation could ameliorate any degradation in the wetland's hydrological ...

Biogeochemial modeling of biodegradation and stable isotope fractionation of DCE in a small-scale wetland

Science.gov (United States)

Alvarez-Zaldívar, Pablo; Imfeld, Gwenaël; Maier, Uli; Centler, Florian; Thullner, Martin

2013-04-01

In recent years, the use of (constructed) wetlands has gained significant attention for the in situ remediation of groundwater contaminated with (chlorinated) organic hydrocarbons. Although many sophisticated experimental methods exist for the assessment of contaminant removal in such wetlands the understanding how changes in wetland hydrochemistry affect the removal processes is still limited. This knowledge gap might be reduced by the use of biogeochemical reactive transport models. This study presents the reactive transport simulation of a small-scale constructed wetland treated with groundwater containing cis-1,2-dichloroethene (cDCE). Simulated processes consider different cDCE biodegradation pathways and the associated carbon isotope fractionation, a set of further (bio)geochemical processes as well as the activity of the plant roots. Spatio-temporal hydrochemical and isotope data from a long-term constructed wetland experiment [1] are used to constrain the model. Simulation results for the initial oxic phase of the wetland experiment indicate carbon isotope enrichment factors typical for cometabolic DCE oxidation, which suggests that aerobic treatment of cDCE is not an optimal remediation strategy. For the later anoxic phase of the experiment model derived enrichment factors indicate reductive dechlorination pathways. This degradation is promoted at all wetland depths by a sufficient availability of electron donor and carbon sources from root exudates, which makes the anoxic treatment of groundwater in such wetlands an effective remediation strategy. In combination with the previous experimental data results from this study suggest that constructed wetlands are viable remediation means for the treatment of cDCE contaminated groundwater. Reactive transport models can improve the understanding of the factors controlling chlorinated ethenes removal, and the used model approach would also allow for an optimization of the wetland operation needed for a complete

Economic valuation of selected direct and indirect use values of the Makgadikgadi wetland system, Botswana

Science.gov (United States)

Setlhogile, Tshepo; Arntzen, Jaap; Mabiza, Collin; Mano, Reneth

Economic valuation of wetlands aims to investigate public preferences for changes in the state of the wetland and the natural resources it constitutes in monetary terms. It provides a means of quantifying the direct and indirect benefits that people derive from wetlands. In addition, it informs management planning and practice about resource options, optimal allocation and also provides information for conservation of the resource. The Makgadikgadi wetland is a unique system that mostly consists of dry pans during most of the year. This study aimed at estimating the value of groundwater recharge and community-based natural resource management (CBNRM) activities within the Makgadikgadi wetland and how these goods and services contribute to the local and national economy. The study used the Total Economic Valuation approach, which considers both the direct and indirect use values of the resource. In essence, the study concentrated on one direct use value (use of resources through CBNRM) and one indirect use value (groundwater recharge). With regard to CBNRM, three community-based organisations (CBOs) were selected for the study and static and dynamic cost-benefit models for these CBOs were developed. The groundwater recharge value was largely determined through desktop review and interviews with stakeholders. The results indicate a small positive contribution of CBOs towards the economy of Botswana and a high potential for communities to derive substantial benefits from the projects because currently benefits realised by communities are limited. CBOs involved in joint venture partnerships with tourism and hunting enterprises benefit more from utilising the wetland’s resources. Groundwater recharge often occurs in areas away from the physical location of the wetland and may not be easily attributable to the wetland. However, the study assessed the value taking into consideration the various sectors which rely on the groundwater resource. The groundwater recharge

Evolution of wetland in Honghe National Nature Reserve from the view of hydrogeology.

Science.gov (United States)

Wu, Xiancang; Dong, Weihong; Lin, Xueyu; Liang, Yukai; Meng, Ying; Xie, Wei

2017-12-31

There is wide concern about the evolution of wetlands, an important component of the global ecosystem. The Honghe National Nature Reserve (HNNR) is an internationally important marsh wetland in China that is at risk of degradation. To gain an improved understanding of how the HNNR wetland developed from 1975 to 2014, typical years, including 1975, 1988, 1996, 2002 and 2014, were selected based on precipitation date. And land cover types of the different years were classified using TM images. The results showed that the wetland evolution mainly reflects transformations between the meadow and wetland land cover types. The landscape index suggests the wetland is degrading. The main drivers of wetland evolution were a warmer and drier climate, the establishment of an irrigation system, and a decrease in the groundwater level. These factors resulted in changes in the quantity of water in the HNNR. We can therefore say that the evolution was driven by changes in the water quantity. Because there have been very few hydrogeological studies in the HNNR, we examined the relationships among precipitation, surface water, and groundwater, all of which significantly influence water quantity. We found that precipitation was the only source of surface water and, while there was certain amount of surface water recharge into the shallow groundwater, the recharge range was limited, which increased the vulnerability of the wetlands. Thus, it is difficult to recharge surface water but easy to lose surface water from the HNNR, which suggests that efforts need to be directed at maintaining the surface water at the optimal level to prevent degradation of the wetland. Copyright © 2017. Published by Elsevier B.V.

Uncertainty quantification of surface-water/groundwater exchange estimates in large wetland systems using Python

Science.gov (United States)

Hughes, J. D.; Metz, P. A.

2014-12-01

Most watershed studies include observation-based water budget analyses to develop first-order estimates of significant flow terms. Surface-water/groundwater (SWGW) exchange is typically assumed to be equal to the residual of the sum of inflows and outflows in a watershed. These estimates of SWGW exchange, however, are highly uncertain as a result of the propagation of uncertainty inherent in the calculation or processing of the other terms of the water budget, such as stage-area-volume relations, and uncertainties associated with land-cover based evapotranspiration (ET) rate estimates. Furthermore, the uncertainty of estimated SWGW exchanges can be magnified in large wetland systems that transition from dry to wet during wet periods. Although it is well understood that observation-based estimates of SWGW exchange are uncertain it is uncommon for the uncertainty of these estimates to be directly quantified. High-level programming languages like Python can greatly reduce the effort required to (1) quantify the uncertainty of estimated SWGW exchange in large wetland systems and (2) evaluate how different approaches for partitioning land-cover data in a watershed may affect the water-budget uncertainty. We have used Python with the Numpy, Scipy.stats, and pyDOE packages to implement an unconstrained Monte Carlo approach with Latin Hypercube sampling to quantify the uncertainty of monthly estimates of SWGW exchange in the Floral City watershed of the Tsala Apopka wetland system in west-central Florida, USA. Possible sources of uncertainty in the water budget analysis include rainfall, ET, canal discharge, and land/bathymetric surface elevations. Each of these input variables was assigned a probability distribution based on observation error or spanning the range of probable values. The Monte Carlo integration process exposes the uncertainties in land-cover based ET rate estimates as the dominant contributor to the uncertainty in SWGW exchange estimates. We will discuss

Optimized remedial groundwater extraction using linear programming

International Nuclear Information System (INIS)

Quinn, J.J.

1995-01-01

Groundwater extraction systems are typically installed to remediate contaminant plumes or prevent further spread of contamination. These systems are expensive to install and maintain. A traditional approach to designing such a wellfield uses a series of trial-and-error simulations to test the effects of various well locations and pump rates. However, the optimal locations and pump rates of extraction wells are difficult to determine when objectives related to the site hydrogeology and potential pumping scheme are considered. This paper describes a case study of an application of linear programming theory to determine optimal well placement and pump rates. The objectives of the pumping scheme were to contain contaminant migration and reduce contaminant concentrations while minimizing the total amount of water pumped and treated. Past site activities at the area under study included disposal of contaminants in pits. Several groundwater plumes have been identified, and others may be present. The area of concern is bordered on three sides by a wetland, which receives a portion of its input budget as groundwater discharge from the pits. Optimization of the containment pumping scheme was intended to meet three goals: (1) prevent discharge of contaminated groundwater to the wetland, (2) minimize the total water pumped and treated (cost benefit), and (3) avoid dewatering of the wetland (cost and ecological benefits). Possible well locations were placed at known source areas. To constrain the problem, the optimization program was instructed to prevent any flow toward the wetland along a user-specified border. In this manner, the optimization routine selects well locations and pump rates so that a groundwater divide is produced along this boundary

Development of a hydrogeological conceptual wetland model in the data-scarce north-eastern region of Kilombero Valley, Tanzania

Science.gov (United States)

Burghof, Sonja; Gabiri, Geofrey; Stumpp, Christine; Chesnaux, Romain; Reichert, Barbara

2018-02-01

Understanding groundwater/surface-water interactions in wetlands is crucial because wetlands provide not only a high potential for agricultural production, but also sensitive and valuable ecosystems. This is especially true for the Kilombero floodplain wetland in Tanzania, which represents a data-scarce region in terms of hydrological and hydrogeological data. A comprehensive approach combining hydrogeological with tracer-based assessments was conducted, in order to develop a conceptual hydrogeological wetland model of the area around the city of Ifakara in the north-eastern region of Kilombero catchment. Within the study site, a heterogeneous porous aquifer, with a range of hydraulic conductivities, is underlain by a fractured-rock aquifer. Groundwater chemistry is mainly influenced by silicate weathering and depends on groundwater residence times related to the hydraulic conductivities of the porous aquifer. Groundwater flows from the hillside to the river during most of the year. While floodwater close to the river is mainly derived from overbank flow of the river, floodwater at a greater distance from the river mainly originates from precipitation and groundwater discharge. Evaporation effects in floodwater increase with increasing distance from the river. In general, the contribution of flood and stream water to groundwater recharge is negligible. In terms of an intensification of agricultural activities in the wetland, several conclusions can be drawn from the conceptual model. Results of this study are valuable as a base for further research related to groundwater/surface-water interactions and the conceptual model can be used in the future to set up numerical flow and transport models.

Relation of streams, lakes, and wetlands to groundwater flow systems

Science.gov (United States)

Winter, Thomas C.

Surface-water bodies are integral parts of groundwater flow systems. Groundwater interacts with surface water in nearly all landscapes, ranging from small streams, lakes, and wetlands in headwater areas to major river valleys and seacoasts. Although it generally is assumed that topographically high areas are groundwater recharge areas and topographically low areas are groundwater discharge areas, this is true primarily for regional flow systems. The superposition of local flow systems associated with surface-water bodies on this regional framework results in complex interactions between groundwater and surface water in all landscapes, regardless of regional topographic position. Hydrologic processes associated with the surface-water bodies themselves, such as seasonally high surface-water levels and evaporation and transpiration of groundwater from around the perimeter of surface-water bodies, are a major cause of the complex and seasonally dynamic groundwater flow fields associated with surface water. These processes have been documented at research sites in glacial, dune, coastal, mantled karst, and riverine terrains. Résumé Les eaux de surface sont parties intégrantes des systèmes aquifères. Les eaux souterraines interagissent avec les eaux de surface dans presque tous les types d'environnements, depuis les petits ruisseaux, les lacs et les zones humides jusqu'aux bassins versants des vallées des grands fleuves et aux lignes de côte. Il est en général admis que les zones topographiquement hautes sont des lieux de recharge des aquifères et les zones basses des lieux de décharge, ce qui est le cas des grands systèmes aquifères régionaux. La superposition de systèmes locaux, associés à des eaux de surface, à l'organisation régionale d'écoulements souterrains résulte d'interactions complexes entre les eaux souterraines et les eaux de surface dans tous les environnements, quelle que soit la situation topographique régionale. Les processus

Drought-induced recharge promotes long-term storage of porewater salinity beneath a prairie wetland

Science.gov (United States)

Levy, Zeno F.; Rosenberry, Donald O.; Moucha, Robert; Mushet, David M.; Goldhaber, Martin B.; LaBaugh, James W.; Fiorentino, Anthony J.; Siegel, Donald I.

2018-02-01

Subsurface storage of sulfate salts allows closed-basin wetlands in the semiarid Prairie Pothole Region (PPR) of North America to maintain moderate surface water salinity (total dissolved solids [TDS] from 1 to 10 g L-1), which provides critical habitat for communities of aquatic biota. However, it is unclear how the salinity of wetland ponds will respond to a recent shift in mid-continental climate to wetter conditions. To understand better the mechanisms that control surface-subsurface salinity exchanges during regional dry-wet climate cycles, we made a detailed geoelectrical study of a closed-basin prairie wetland (P1 in the Cottonwood Lake Study Area, North Dakota) that is currently experiencing record wet conditions. We found saline lenses of sulfate-rich porewater (TDS > 10 g L-1) contained in fine-grained wetland sediments 2-4 m beneath the bathymetric low of the wetland and within the currently ponded area along the shoreline of a prior pond stand (c. 1983). During the most recent drought (1988-1993), the wetland switched from a groundwater discharge to recharge function, allowing salts dissolved in surface runoff to move into wetland sediments beneath the bathymetric low of the basin. However, groundwater levels during this time did not decline to the elevation of the saline lenses, suggesting these features formed during more extended paleo-droughts and are stable in the subsurface on at least centennial timescales. We hypothesize a "drought-induced recharge" mechanism that allows wetland ponds to maintain moderate salinity under semiarid climate. Discharge of drought-derived saline groundwater has the potential to increase the salinity of wetland ponds during wet climate.

Determination of the health of Lunyangwa wetland using Wetland Classification and Risk Assessment Index

Science.gov (United States)

Wanda, Elijah M. M.; Mamba, Bhekie B.; Msagati, Titus A. M.; Msilimba, Golden

2016-04-01

Wetlands are major sources of various ecological goods and services including storage and distribution of water in space and time which help in ensuring the availability of surface and groundwater throughout the year. However, there still remains a poor understanding of the range of values of water quality parameters that occur in wetlands either in its impacted state or under natural conditions. It was thus imperative to determine the health of Lunyangwa wetland in Mzuzu City in Malawi in order to classify and determine its state. This study used the Escom's Wetland Classification and Risk Assessment Index Field Guide to determine the overall characteristics of Lunyangwa wetland and to calculate its combined Wetland Index Score. Data on site information, field measurements (i.e. EC, pH, temperature and DO) and physical characteristics of Lunyangwa wetland were collected from March, 2013 to February, 2014. Results indicate that Lunyangwa wetland is a largely open water zone which is dominated by free-floating plants on the water surface, beneath surface and emergent in substrate. Furthermore, the wetland can be classified as of a C ecological category (score = 60-80%), which has been moderately modified with moderate risks of the losses and changes occurring in the natural habitat and biota in the wetland. It was observed that the moderate modification and risk were largely because of industrial, agricultural, urban/social catchment stressors on the wetland. This study recommends an integrated and sustainable management approach coupled with continuous monitoring and evaluation of the health of the wetland for all stakeholders in Mzuzu City. This would help to maintain the health of Lunyangwa wetland which is currently at risk of being further modified due to the identified catchment stressors.

Use of Isotopic Techniques for the Assessment of Hydrological Processes in Wetlands (Cienaga Colombia)

Energy Technology Data Exchange (ETDEWEB)

Betancur, T.; Santa, D.; Palacio, P.; Palacio, C.; Wills, B.; Hoyos, D. A. [Universidad de Antioquia, Medellin (Colombia)

2013-07-15

The Cienaga Colombia wetland is located in the Bajo Cauca Antioqueno region where the 'Man' river flows into the Cauca River. Hydrological processes on the Cienaga Colombia wetland are complex because of the interactive effects of both local and regional elements, associated with a typical tropical wet climatic regime. In this groundwater dependent wetland hydrological studies have been conducted, including hydrochemical analyses and isotope tracers, to describe and understand the interactions between groundwater and surface water, not only for the wetland itself but also for the entire catchment area. Rain samples (five year record) were used to obtain the LML: {delta}{sup 2}H = 8.03 {delta}{sup 18}O +9.9. The evaporation line is: {delta}{sup 2}H = 5.9 {delta}{sup 18}O - 7.3. According to the analyses, both groundwater and surface waters have the same isotopic signatures. Unsustainable land use practices along with current and predicted global environmental changes may cause negative impacts on the hydrological functioning of the region, affecting primarily, but not exclusively, evapotranspiration-recharge processes and the sustainability of the entire system. (author)

Iron Mineralogy and Uranium-Binding Environment in the Rhizosphere of a Wetland Soil

Science.gov (United States)

Wetlands mitigate the migration of groundwater contaminants through a series of biogeochemical gradients that enhance multiple contaminant-binding processes. The hypothesis of this study was that wetland plant roots contribute organic carbon and release O2 within the ...

Estimating wetland connectivity to streams in the Prairie Pothole Region: An isotopic and remote sensing approach

Science.gov (United States)

Brooks, J. R.; Mushet, David M.; Vanderhoof, Melanie; Leibowitz, Scott G.; Neff, Brian; Christensen, J. R.; Rosenberry, Donald O.; Rugh, W. D.; Alexander, L.C.

2018-01-01

Understanding hydrologic connectivity between wetlands and perennial streams is critical to understanding the reliance of stream flow on inputs from wetlands. We used the isotopic evaporation signal in water and remote sensing to examine wetland‐stream hydrologic connectivity within the Pipestem Creek watershed, North Dakota, a watershed dominated by prairie‐pothole wetlands. Pipestem Creek exhibited an evaporated‐water signal that had approximately half the isotopic‐enrichment signal found in most evaporatively enriched prairie‐pothole wetlands. Groundwater adjacent to Pipestem Creek had isotopic values that indicated recharge from winter precipitation and had no significant evaporative enrichment, indicating that enriched surface water did not contribute significantly to groundwater discharging into Pipestem Creek. The estimated surface water area necessary to generate the evaporation signal within Pipestem Creek was highly dynamic, varied primarily with the amount of discharge, and was typically greater than the immediate Pipestem Creek surface water area, indicating that surficial flow from wetlands contributed to stream flow throughout the summer. We propose a dynamic range of spilling thresholds for prairie‐pothole wetlands across the watershed allowing for wetland inputs even during low‐flow periods. Combining Landsat estimates with the isotopic approach allowed determination of potential (Landsat) and actual (isotope) contributing areas in wetland‐dominated systems. This combined approach can give insights into the changes in location and magnitude of surface water and groundwater pathways over time. This approach can be used in other areas where evaporation from wetlands results in a sufficient evaporative isotopic signal.

A simple procedure to model water level fluctuations in partially inundated wetlands

NARCIS (Netherlands)

Spieksma, JFM; Schouwenaars, JM

When modelling groundwater behaviour in wetlands, there are specific problems related to the presence of open water in small-sized mosaic patterns. A simple quasi two-dimensional model to predict water level fluctuations in partially inundated wetlands is presented. In this model, the ratio between

Hydrogeology and hydrology of the Punta Cabullones wetland area, Ponce, southern Puerto Rico, 2007-08

Science.gov (United States)

Rodríguez-Martínez, Jesús; Soler-López, Luis R.

2014-01-01

modifying the water quality and stage of the wetland in Punta Cabullones. The role of the tidal fluctuations becomes important during those times when the outlets/inlets to the sea are not blocked by a sand bar and is allowed to freely flow into the wetland interior. The salinity of the wetland varies from brackish to hypersaline. The hypersaline conditions, including the occurrence of saltflats, within the Punta Cabullones wetland area result from a high evapotranspiration rate. The hypersaline conditions are further enhanced by a sand bar that blocks the inlet/outlet of the wetland’s easternmost channel, particularly during the dry season. Groundwater in Punta Cabullones mostly is present within beds of silisiclastic sand and gravel. During the study period, the depth to groundwater did not exceed 4 feet below land surface. The movement and direction of the groundwater flow in Punta Cabullones are driven by density variations that in turn result from the wide range of salinities in the groundwater. The salinity of the groundwater decreases within the first 60 to 100 feet of depth and decreases outward from a mound of hypersaline groundwater centered on piezometer nest PN2. The main groundwater types within the Punta Cabullones area vary from calcium-bicarbonate type in the northernmost part of the study area to a predominantly sodium-potassium-chloride groundwater type southward. According to stable-isotope data, groundwater within the study area is both modern meteoric water and seawater highly affected by evaporation. The chemical and stable-isotopic character of local groundwater is highly influenced by evapotranspiration because of its shallow depth. Equivalent freshwater heads indicate groundwater moves away from a mound centered on piezometer nest PN2, in a pattern similar to the spatial distribution of groundwater salinity. Vertical groundwater flow occurs in Punta Cabullones due to local differences in density. In the wetland subarea of Punta Cabullones

Rainfall Variability, Wetland Persistence, and Water–Carbon Cycle Coupling in the Upper Zambezi River Basin in Southern Africa

Directory of Open Access Journals (Sweden)

Lauren E. L. Lowman

2018-05-01

Full Text Available The Upper Zambezi River Basin (UZRB delineates a complex region of topographic, soil and rainfall gradients between the Congo rainforest and the Kalahari Desert. Satellite imagery shows permanent wetlands in low-lying convergence zones where surface–groundwater interactions are vigorous. A dynamic wetland classification based on MODIS Nadir BRDF-Adjusted Reflectance is developed to capture the inter-annual and seasonal changes in areal extent due to groundwater redistribution and rainfall variability. Simulations of the coupled water–carbon cycles of seasonal wetlands show nearly double rates of carbon uptake as compared to dry areas, at increasingly lower water-use efficiencies as the dry season progresses. Thus, wetland extent and persistence into the dry season is key to the UZRB’s carbon sink and water budget. Whereas groundwater recharge governs the expansion of wetlands in the rainy season under large-scale forcing, wetland persistence in April–June (wet–dry transition months is tied to daily morning fog and clouds, and by afternoon land–atmosphere interactions (isolated convection. Rainfall suppression in July–September results from colder temperatures, weaker regional circulations, and reduced instability in the lower troposphere, shutting off moisture recycling in the dry season despite high evapotranspiration rates. The co-organization of precipitation and wetlands reflects land–atmosphere interactions that determine wetland seasonal persistence, and the coupled water and carbon cycles.

Preliminary Analysis of the Role of Wetlands and Rivers in the Groundwater Discharge of the Guarani Aquifer System in NE Argentina

Energy Technology Data Exchange (ETDEWEB)

Vives, L., E-mail: lvives@faa.unicen.edu.ar [Instituto de Hidrologia de Llanuras, Universidad Nacional del Centro de la Provincia de Buenos Aires, Azul (Argentina); Rodriguez, L. [Centro de Estudios Hidroambientales, Facultad de Ingenieria y Ciencias Hidricas, Universidad Nacional del Litoral, Santa Fe (Argentina); Manzano, M. [Escuela de Ingenieria de Caminos y de Minas, Universidad Politecnica de Cartagena, Cartagena (Spain); Valladares, A. [Subsecretaria de Recursos Hidricos (Argentina); Aggarwal, P. K.; Araguas Araguas, L. [International Atomic Energy Angency, Vienna (Austria)

2013-07-15

The Guarani Aquifer System (GAS) is the largest aquifer in South America. Previous regional hydrochemical and isotopic studies suggested that discharge may occur at wetlands and reaches of the Parana and Uruguay Rivers. Preliminary findings of a project aimed at verifying the discharge hypothesis on the southern GAS region are presented. The hydrochemical- isotopic composition of 17 samples from surface and groundwater in that area were analysed. Some waters showed chemical facies and isotopic (stable isotope and carbon-14) signatures similar to the formerly identified as GAS+pre-GAS formations. Admixtures between modern and GAS+pre-GAS waters were found at depths between less than 100 m and 200 m. A 96 m deep well located near the Ibera lagoon showed chemical and isotopic composition indicating presence of GAS waters. The hydraulic gradient favours upward flow near the wetlands, but surface waters seem to originate from local recharge. Investigations continue, incorporating {sup 222}Rn and new sampling sites. (author)

Wetland Water Cooling Partnership: The Use of Constructed Wetlands to Enhance Thermoelectric Power Plant Cooling and Mitigate the Demand of Surface Water Use

Energy Technology Data Exchange (ETDEWEB)

Apfelbaum, Steven L. [Applied Ecological Services Inc., Brodhead, WI (United States); Duvall, Kenneth W. [Sterling Energy Services, LLC, Atlanta, GA (United States); Nelson, Theresa M. [Applied Ecological Services Inc., Brodhead, WI (United States); Mensing, Douglas M. [Applied Ecological Services Inc., Brodhead, WI (United States); Bengtson, Harlan H. [Sterling Energy Services, LLC, Atlanta, GA (United States); Eppich, John [Waterflow Consultants, Champaign, IL (United States); Penhallegon, Clayton [Sterling Energy Services, LLC, Atlanta, GA (United States); Thompson, Ry L. [Applied Ecological Services Inc., Brodhead, WI (United States)

2013-12-01

Through the Phase I study segment of contract #DE-NT0006644 with the U.S. Department of Energy’s National Energy Technology Laboratory, Applied Ecological Services, Inc. and Sterling Energy Services, LLC (the AES/SES Team) explored the use of constructed wetlands to help address stresses on surface water and groundwater resources from thermoelectric power plant cooling and makeup water requirements. The project objectives were crafted to explore and develop implementable water conservation and cooling strategies using constructed wetlands (not existing, naturally occurring wetlands), with the goal of determining if this strategy has the potential to reduce surface water and groundwater withdrawals of thermoelectric power plants throughout the country. Our team’s exploratory work has documented what appears to be a significant and practical potential for augmenting power plant cooling water resources for makeup supply at many, but not all, thermoelectric power plant sites. The intent is to help alleviate stress on existing surface water and groundwater resources through harvesting, storing, polishing and beneficially re-using critical water resources. Through literature review, development of conceptual created wetland plans, and STELLA-based modeling, the AES/SES team has developed heat and water balances for conventional thermoelectric power plants to evaluate wetland size requirements, water use, and comparative cooling technology costs. The ecological literature on organism tolerances to heated waters was used to understand the range of ecological outcomes achievable in created wetlands. This study suggests that wetlands and water harvesting can provide a practical and cost-effective strategy to augment cooling waters for thermoelectric power plants in many geographic settings of the United States, particularly east of the 100th meridian, and in coastal and riverine locations. The study concluded that constructed wetlands can have significant positive

Transfer of tracers and pesticides in lab scale wetland systems: the role of vegetation

Science.gov (United States)

Durst, R.; Imfeld, G.; Lange, J.

2012-04-01

Surface wetlands can collect contaminated runoff from urban or agricultural catchments and have intrinsic physical, chemical and biological retention and removal processes useful for mitigating contaminants, including pesticides, and thus limiting the contamination of aquatic ecosystems. Yet little is known about the transfer of pesticides between wetlands collecting pesticides runoff and groundwater, and the subsequent threat of groundwater contamination. In particular, the influence of wetland vegetation and related processes during pesticide transfer is largely unknown. Here we evaluate the transfer of the widely used herbicide Isoproturon (IPU) and the fungicide Metalaxyl (MTX) with that of Uranine (UR) and Sulphorhodamine (SRB) in a vegetated and a non-vegetated lab-scale wetland. UR and SRB had successfully served as a reference for pesticides in surface wetlands. We filled two 65 cm long and 15 cm diameter borosilicate columns with sediment cores from a wetland, one without and one with vegetation (Phragmites australis, Cav.). When a constant flow-through rate of 0.33 ml min-1 was reached, tracers and pesticides were injected simultaneously and continuously. The hydrological mass balance and tracer concentrations were measured daily at the outlet of the lab-scale wetland. Samples for pesticides and hydrochemical analyses were collected biweekly. The lab-scale wetlands were covered to limit evaporation and light decay of injected compounds. The reactive transfer of compounds in the vegetated and non-vegetated lab-scale wetland was compared based on breakthrough curves (BTC's) and model parameters of the lumped parameter model CXTFIT. The hydrologic balance revealed that the intensity of transpiration and hence plant activity in the lab-scale wetlands progressively decreased and then apparently ceased after about eight days following continuous pesticide injection. In this first phase, no significant difference in the hydrologic balances could be observed

Simulation of groundwater flow and hydrologic effects of groundwater withdrawals from the Kirkwood-Cohansey aquifer system in the Pinelands of southern New Jersey

Science.gov (United States)

Charles, Emmanuel; Nicholson, Robert S.

2012-01-01

The Kirkwood-Cohansey aquifer system is an important source of present and future water supply in southern New Jersey. Because this unconfined aquifer system also supports sensitive wetland and aquatic habitats within the New Jersey Pinelands (Pinelands), water managers and policy makers need up-to-date information, data, and projections that show the effects of potential increases in groundwater withdrawals on these habitats. Finite-difference groundwater flow models (MODFLOW) were constructed for three drainage basins (McDonalds Branch Basin, 14.3 square kilometers (km2); Morses Mill Stream Basin, 21.63 km2; and Albertson Brook Basin, 52.27 km2) to estimate the effects of potential increases in groundwater withdrawals on water levels and the base-flow portion of streamflow, in wetland and aquatic habitats. Three models were constructed for each drainage basin: a transient model consisting of twenty-four 1-month stress periods (October 2004 through September 2006); a transient model to simulate the 5- to 10-day aquifer tests that were performed as part of the study; and a high-resolution, steady-state model used to assess long-term effects of increased groundwater withdrawals on water levels in wetlands and on base flow. All models were constructed with the same eight-layer structure. The smallest horizontal cell dimensions among the three model areas were 150 meters (m) for the 24-month transient models, 10 m for the steady-state models, and 3 m for the transient aquifer-test models. Boundary flows of particular interest to this study and represented separately are those for wetlands, streams, and evapotranspiration. The final variables calibrated from both transient models were then used in steady-state models to assess the long-term effects of increased groundwater withdrawals on water levels in wetlands and on base flow. Results of aquifer tests conducted in the three study areas illustrate the effects of withdrawals on water levels in wetlands and on base

Novel Large Sulfur Bacteria in the Metagenomes of Groundwater-Fed Chemosynthetic Microbial Mats in the Lake Huron Basin.

Science.gov (United States)

Sharrar, Allison M; Flood, Beverly E; Bailey, Jake V; Jones, Daniel S; Biddanda, Bopaiah A; Ruberg, Steven A; Marcus, Daniel N; Dick, Gregory J

2017-01-01

Little is known about large sulfur bacteria (LSB) that inhabit sulfidic groundwater seeps in large lakes. To examine how geochemically relevant microbial metabolisms are partitioned among community members, we conducted metagenomic analysis of a chemosynthetic microbial mat in the Isolated Sinkhole, which is in a deep, aphotic environment of Lake Huron. For comparison, we also analyzed a white mat in an artesian fountain that is fed by groundwater similar to Isolated Sinkhole, but that sits in shallow water and is exposed to sunlight. De novo assembly and binning of metagenomic data from these two communities yielded near complete genomes and revealed representatives of two families of LSB. The Isolated Sinkhole community was dominated by novel members of the Beggiatoaceae that are phylogenetically intermediate between known freshwater and marine groups. Several of these Beggiatoaceae had 16S rRNA genes that contained introns previously observed only in marine taxa. The Alpena fountain was dominated by populations closely related to Thiothrix lacustris and an SM1 euryarchaeon known to live symbiotically with Thiothrix spp. The SM1 genomic bin contained evidence of H 2 -based lithoautotrophy. Genomic bins of both the Thiothrix and Beggiatoaceae contained genes for sulfur oxidation via the rDsr pathway, H 2 oxidation via Ni-Fe hydrogenases, and the use of O 2 and nitrate as electron acceptors. Mats at both sites also contained Deltaproteobacteria with genes for dissimilatory sulfate reduction ( sat, apr , and dsr ) and hydrogen oxidation (Ni-Fe hydrogenases). Overall, the microbial mats at the two sites held low-diversity microbial communities, displayed evidence of coupled sulfur cycling, and did not differ largely in their metabolic potentials, despite the environmental differences. These results show that groundwater-fed communities in an artesian fountain and in submerged sinkholes of Lake Huron are a rich source of novel LSB, associated heterotrophic and sulfate

Novel Large Sulfur Bacteria in the Metagenomes of Groundwater-Fed Chemosynthetic Microbial Mats in the Lake Huron Basin

Directory of Open Access Journals (Sweden)

Allison M. Sharrar

2017-05-01

Full Text Available Little is known about large sulfur bacteria (LSB that inhabit sulfidic groundwater seeps in large lakes. To examine how geochemically relevant microbial metabolisms are partitioned among community members, we conducted metagenomic analysis of a chemosynthetic microbial mat in the Isolated Sinkhole, which is in a deep, aphotic environment of Lake Huron. For comparison, we also analyzed a white mat in an artesian fountain that is fed by groundwater similar to Isolated Sinkhole, but that sits in shallow water and is exposed to sunlight. De novo assembly and binning of metagenomic data from these two communities yielded near complete genomes and revealed representatives of two families of LSB. The Isolated Sinkhole community was dominated by novel members of the Beggiatoaceae that are phylogenetically intermediate between known freshwater and marine groups. Several of these Beggiatoaceae had 16S rRNA genes that contained introns previously observed only in marine taxa. The Alpena fountain was dominated by populations closely related to Thiothrix lacustris and an SM1 euryarchaeon known to live symbiotically with Thiothrix spp. The SM1 genomic bin contained evidence of H2-based lithoautotrophy. Genomic bins of both the Thiothrix and Beggiatoaceae contained genes for sulfur oxidation via the rDsr pathway, H2 oxidation via Ni-Fe hydrogenases, and the use of O2 and nitrate as electron acceptors. Mats at both sites also contained Deltaproteobacteria with genes for dissimilatory sulfate reduction (sat, apr, and dsr and hydrogen oxidation (Ni-Fe hydrogenases. Overall, the microbial mats at the two sites held low-diversity microbial communities, displayed evidence of coupled sulfur cycling, and did not differ largely in their metabolic potentials, despite the environmental differences. These results show that groundwater-fed communities in an artesian fountain and in submerged sinkholes of Lake Huron are a rich source of novel LSB, associated heterotrophic

Dependence of Wetland Vegetation on Hydrological Regime in a Large Floodplain Lake (Poyang Lake) in the Middle Yangtze River

Science.gov (United States)

Zhang, Q.; Tan, Z.; Xu, X.

2017-12-01

Exemplified in the Yangtze River floodplain lake, Poyang Lake, investigations were carried out to examine the dependence of vegetation on hydrological variables. The Lake is one of the few lakes that remain naturally connected to the Yangtze River. The Lake surface expanses to 4000 km2 in wet seasons, and reduces to less than 1000 km2 in dry seasons, creating some 3000 km2 vital wetland habitats for many animals. Remote sensing was used to obtain the spatial distribution of wetland vegetations. A lake hydrodynamic model using MIKE 21 was employed to determine the variability of wetland inundation. In-situ high time frequency observations of climate, soil moisture, and groundwater depth were also conducted in a typical wetland transect of 1 km long. Vegetations were sampled periodically to obtain species composition, diversity and biomass. Results showed that the spatial distribution of vegetation highly depended on the inundation duration and depth. Optimal hydrological variables existed for the typical vegetations in Poyang Lake wetland. Numerical simulations using HYDRUS-1D further demonstrated that both groundwater depth and soil moisture had significant effects on the growth of vegetation and the water demand in terms of transpiration, even in a wet climate zone such as middle Yangtze River. It was found that the optimal groundwater depths existed for both above- and belowground biomass. Simulation scenarios indicated that climate changes and human modification of hydrology would affect the water usage of vegetation and may cause a strategic adaptation of the vegetation to the stressed hydrological conditions. The study revealed new knowledge on the high dependence of wetland vegetation on both surface water regime and groundwater depths, in wet climate zone. Outcomes of this study may provide support for an integrated management of balancing water resources development and wetland sustainability maintenance in Poyang Lake, and other floodplain wetlands, with

Hydrogeologic characterization and assessment of bioremediation of chlorinated benzenes and benzene in wetland areas, Standard Chlorine of Delaware, Inc. Superfund Site, New Castle County, Delaware, 2009-12

Science.gov (United States)

Lorah, Michelle M.; Walker, Charles W.; Baker, Anna C.; Teunis, Jessica A.; Emily Majcher,; Brayton, Michael J.; Raffensperger, Jeff P.; Cozzarelli, Isabelle M.

2015-01-01

Wetlands at the Standard Chlorine of Delaware, Inc. Superfund Site (SCD) in New Castle County, Delaware, are affected by contamination with chlorobenzenes and benzene from past waste storage and disposal, spills, leaks, and contaminated groundwater discharge. In cooperation with the U.S. Environmental Protection Agency, the U.S. Geological Survey began an investigation in June 2009 to characterize the hydrogeology and geochemistry in the wetlands and assess the feasibility of monitored natural attenuation and enhanced bioremediation as remedial strategies. Groundwater flow in the wetland study area is predominantly vertically upward in the wetland sediments and the underlying aquifer, and groundwater discharge accounts for a minimum of 47 percent of the total discharge for the subwatershed of tidal Red Lion Creek. Thus, groundwater transport of contaminants to surface water could be significant. The major contaminants detected in groundwater in the wetland study area included benzene, monochlorobenzene, and tri- and di-chlorobenzenes. Shallow wetland groundwater in the northwest part of the wetland study area was characterized by high concentrations of total chlorinated benzenes and benzene (maximum about 75,000 micrograms per liter [μg/L]), low pH, and high chloride. In the northeast part of the wetland study area, wetland groundwater had low to moderate concentrations of total chlorinated benzenes and benzene (generally not greater than 10,000 μg/L), moderate pH, and high sulfate concentrations. Concentrations in the groundwater in excess of 1 percent of the solubility of the individual chlorinated benzenes indicate that a contaminant source is present in the wetland sediments as dense nonaqueous phase liquids (DNAPLs). Consistently higher contaminant concentrations in the shallow wetland groundwater than deeper in the wetland sediments or the aquifer also indicate a continued source in the wetland sediments, which could include dissolution of DNAPLs and

Teaching multidisciplinary environmental science in a wetland setting

Science.gov (United States)

Panno, S.V.; Hackley, Keith C.; Nuzzo, V.A.

1998-01-01

High-school students from across the country came to the Illinois State Geological Survey (ISGS) to assist in field research for two weeks in July, 1994, as part of The Johns Hopkins University Center for Talented Youth Summer Experience Program. During the research project at the ISGS, students were exposed to a multidisciplinary scientific investigation where geology, hydrogeology, ground-water chemistry, and plant biology could be directly observed and used to study the potentially destructive effects of nearby road and house construction on a fen-wetland complex. Experienced researchers provided classroom and field instruction to the students prior to leading the field investigations. Following field work, the students returned to the ISGS laboratories where they assisted with the chemical analysis of ground-water samples and compiled and interpreted their data. The students wrote up their results in standard scientific report format and gave oral presentations covering various aspects of the project to an audience of ISGS scientists and guests. The results of their work, which showed changes in the wetland's plant biodiversity resulting from urban development within the watershed, will provide data needed for the preservation of biodiversity in these and other wetlands.

Accommodating state shifts within the conceptual framework of the wetland continuum

Science.gov (United States)

Mushet, David M.; McKenna, Owen; LaBaugh, James W.; Euliss, Ned H.; Rosenberry, Donald O.

2018-01-01

The Wetland Continuum is a conceptual framework that facilitates the interpretation of biological studies of wetland ecosystems. Recently summarized evidence documenting how a multi-decadal wet period has influenced aspects of wetland, lake and stream systems in the southern prairie-pothole region of North America has revealed the potential for wetlands to shift among alternate states. We propose that incorporation of state shifts into the Wetland Continuum, as originally proposed or as modified by Hayashi et al., is a relatively simple matter if one allows for shifts of wetlands along the horizontal, groundwater axis of the framework under conditions of extreme and sustained wet or dry conditions. We suggest that the ease by which state shifts can be accommodated within both the original and modified frameworks of the Wetland Continuum is a testament to the robustness of the concept when it is related to the alternative-stable-state concept.

Natural uranium and strontium isotope tracers of water sources and surface water-groundwater interactions in arid wetlands: Pahranagat Valley, Nevada, USA

Science.gov (United States)

Paces, James B.; Wurster, Frederic C.

2014-01-01

Near-surface physical and chemical process can strongly affect dissolved-ion concentrations and stable isotope compositions of water in wetland settings, especially under arid climate conditions. In contrast, heavy radiogenic isotopes of strontium (87Sr/86Sr) and uranium (234U/238U) remain largely unaffected and can be used to help identify unique signatures from different sources and quantify end-member mixing that would otherwise be difficult to determine. The utility of combined Sr and U isotopes are demonstrated in this study of wetland habitats on the Pahranagat National Wildlife Refuge, which depend on supply from large-volume springs north of the Refuge, and from small-volume springs and seeps within the Refuge. Water budgets from these sources have not been quantified previously. Evaporation, transpiration, seasonally variable surface flow, and water management practices complicate the use of conventional methods for determining source contributions and mixing relations. In contrast, 87Sr/86Sr and 234U/238U remain unfractionated under these conditions, and compositions at a given site remain constant. Differences in Sr- and U-isotopic signatures between individual sites can be related by simple two- or three-component mixing models. Results indicate that surface flow constituting the Refuge’s irrigation source consists of a 65:25:10 mixture of water from two distinct regionally sourced carbonate aquifer springs, and groundwater from locally sourced volcanic aquifers. Within the Refuge, contributions from the irrigation source and local groundwater are readily determined and depend on proximity to those sources as well as water management practices.

The role of evapotranspiration in the groundwater hydrochemistry of an arid coastal wetland (Península Valdés, Argentina)

International Nuclear Information System (INIS)

Alvarez, María del Pilar; Carol, Eleonora; Dapeña, Cristina

2015-01-01

Coastal wetlands are complex hydrogeological systems, in which saline groundwater usually occurs. Salinity can be attributed to many origins, such as dissolution of minerals in the sediments, marine contribution and evapotranspiration, among others. The aim of this paper is to evaluate the processes that condition the hydrochemistry of an arid marsh, Playa Fracasso, located in Patagonia, Argentina. A study of the dynamics and geochemistry of the groundwater was carried out in each hydrogeomorphological unit, using major ion and isotope ( 18 O and 2 H) data, soil profiles descriptions and measurements, and recording of water tables in relation to the tidal flow. Water balances and analytical models based on isotope data were used to quantify the evaporation processes and to define the role of evaporation in the chemical composition of water. The results obtained show that the groundwater salinity of the marsh comes mainly from the tidal inflow, to which the halite and gypsum dissolution is added. These mineral facies are the result of the total evaporation of the marine water flooding that occurs mostly at the spring high tides. The isotope relationships in the fan and bajada samples show the occurrence of evaporation processes. Such processes, however, are not mainly responsible for the saline content of groundwater, which is actually generated by the dissolution of the typical evaporite facies of the arid environment sediments. It is concluded that the evapotranspiration processes condition groundwater quality. This is not only due to the saline enrichment caused by the evapotranspiration of shallow water, but also because such processes are the main drivers of the formation of soluble salts, which are then incorporated into the water by groundwater or tidal flow. - Highlights: • Tidal inflow and evapotranspiration processes condition the salinity of the marsh. • The total evaporation of marine water led the halite and gypsum precipitation. • The dissolution

Abundance of Alnus incana ssp. rugosa in Adirondack Mountain shrub wetlands and its influence on inorganic nitrogen

International Nuclear Information System (INIS)

Kiernan, B.D.; Hurd, T.M.; Raynal, D.J.

2003-01-01

The presence of the nitrogen-fixing shrub, Alnus incana ssp. rugosa, influences the concentration of inorganic nitrogen in surface waters in the Adirondack Mountain region of northern New York. - The purpose of this research was to determine the abundance of the nitrogen-fixing shrub, Alnus incana ssp. rugosa (speckled alder), in shrub wetlands of the Adirondack Mountain region of New York State and to determine whether its abundance affects the concentration or accumulation of inorganic nitrogen in wetland substrates. Alder/willow wetlands are the second most common wetland type in the Adirondack region. The Adirondack Park Agency's digital GIS database of wetland types was used to determine the areal extent of alder/willow wetlands in the Adirondacks. Randomly selected wetlands were sampled to determine the size and abundance of alder. Alder densities averaged ∼7000 stems ha -1 and alder was present in 75% of the wetlands. As an indication of short-term accumulation of NO 3 - and NH 4 + in wetland substrates, ion exchange resins were used to sample ground water in high and low alder density wetlands as well as from wetlands lacking alder and dominated by conifers. Additionally, NO 3 - and NH 4 + concentrations in ground water samples were measured. NH 4 + accumulation levels from exchange resins were low for all wetland types while groundwater NH 4 + concentration was highest in the low-density alder sites. Wetlands with high alder density had approximately six times higher NO 3 - accumulation than other wetlands. Substrate groundwater NO 3 - concentrations in wetlands of high-density alder exceeded by three times levels in low or no alder wetlands, showing the importance of alder to local N budgets. To assess the recovery of shrub wetlands from acidification, future studies should determine the fate of fixed N in wetland systems

Effects of groundwater-flow paths on nitrate concentrations across two riparian forest corridors

Science.gov (United States)

Speiran, Gary K.

2010-01-01

Groundwater levels, apparent age, and chemistry from field sites and groundwater-flow modeling of hypothetical aquifers collectively indicate that groundwater-flow paths contribute to differences in nitrate concentrations across riparian corridors. At sites in Virginia (one coastal and one Piedmont), lowland forested wetlands separate upland fields from nearby surface waters (an estuary and a stream). At the coastal site, nitrate concentrations near the water table decreased from more than 10 mg/L beneath fields to 2 mg/L beneath a riparian forest buffer because recharge through the buffer forced water with concentrations greater than 5 mg/L to flow deeper beneath the buffer. Diurnal changes in groundwater levels up to 0.25 meters at the coastal site reflect flow from the water table into unsaturated soil where roots remove water and nitrate dissolved in it. Decreases in aquifer thickness caused by declines in the water table and decreases in horizontal hydraulic gradients from the uplands to the wetlands indicate that more than 95% of the groundwater discharged to the wetlands. Such discharge through organic soil can reduce nitrate concentrations by denitrification. Model simulations are consistent with field results, showing downward flow approaching toe slopes and surface waters to which groundwater discharges. These effects show the importance of buffer placement over use of fixed-width, streamside buffers to control nitrate concentrations.

A preliminary analysis of water chemistry of the Mkuze Wetland ...

African Journals Online (AJOL)

drinie

2002-01-01

Jan 1, 2002 ... The Mkuze Wetland System in northern KwaZulu-Natal constitutes an ... water, groundwater, pan and reed swamp sites, as well as a rainwater sample. ... runoff that drains catchments, whereas aquatic ecosystems are.

Using Halogens (Cl, Br, F, I) and Stable Isotopes of Water (δ18O, δ2H) to Trace Hydrological and Biogeochemical Processes in Prairie Wetlands

Science.gov (United States)

Levy, Z. F.; Lu, Z.; Mills, C. T.; Goldhaber, M. B.; Rosenberry, D. O.; Mushet, D.; Siegel, D. I.; Fiorentino, A. J., II; Gade, M.; Spradlin, J.

2014-12-01

Prairie pothole wetlands are ubiquitous features of the Great Plains of North America, and important habitat for amphibians and migratory birds. The salinity of proximal wetlands varies highly due to groundwater-glacial till interactions, which influence wetland biota and associated ecosystem functions. Here we use halogens and stable isotopes of water to fingerprint hydrological and biogeochemical controls on salt cycling in a prairie wetland complex. We surveyed surface, well, and pore waters from a groundwater recharge wetland (T8) and more saline closed (P1) and open (P8) basin discharge wetlands in the Cottonwood Lake Study Area (ND) in August/October 2013 and May 2014. Halogen concentrations varied over a broad range throughout the study area (Cl = 2.2 to 170 mg/L, Br = 13 to 2000 μg/L, F = evaporation-enriched pond water (δ18O = -9.5 to -2.71 ‰) mixes with shallow groundwater in the top 0.6 m of fringing wetland soils and 1.2 m of the substrate in the center of P1. Our results suggest endogenous sources for Br and I within the prairie landscape that may be controlled by biological mechanisms or weathering of shale from glacial till.

Simulation of integrated surface-water/ground-water flow and salinity for a coastal wetland and adjacent estuary

Science.gov (United States)

Langevin, C.; Swain, E.; Wolfert, M.

2005-01-01

The SWIFT2D surface-water flow and transport code, which solves the St Venant equations in two dimensions, was coupled with the SEAWAT variable-density ground-water code to represent hydrologic processes in coastal wetlands and adjacent estuaries. A sequentially coupled time-lagged approach was implemented, based on a variable-density form of Darcy's Law, to couple the surface and subsurface systems. The integrated code also represents the advective transport of salt mass between the surface and subsurface. The integrated code was applied to the southern Everglades of Florida to quantify flow and salinity patterns and to evaluate effects of hydrologic processes. Model results confirm several important observations about the coastal wetland: (1) the coastal embankment separating the wetland from the estuary is overtopped only during tropical storms, (2) leakage between the surface and subsurface is locally important in the wetland, but submarine ground-water discharge does not contribute large quantities of freshwater to the estuary, and (3) coastal wetland salinities increase to near seawater values during the dry season, and the wetland flushes each year with the onset of the wet season. ?? 2005 Elsevier B.V. All rights reserved.

Hydrological challenges to groundwater trading: lessons from south-west Western Australia

OpenAIRE

Skurray, James H.; Roberts, E.J.; Pannell, David J.

2013-01-01

Perth, Western Australia (pop. 1.6m) derives 60% of its public water supply from the Gnangara groundwater system (GGS). Horticulture, domestic self-supply, and municipal parks are other major consumers of GGS groundwater. The system supports important wetlands and groundwater-dependent ecosystems. Underlying approximately 2,200 km2 of the Swan Coastal Plain, the GGS comprises several aquifer levels with partial interconnectivity. Supplies of GGS groundwater are under unprecedented stress, due...

Ebullitive methane emissions from oxygenated wetland streams

Science.gov (United States)

Crawford, John T.; Stanley, Emily H.; Spawn, Seth A.; Finlay, Jacques C.; Striegl, Robert G.

2014-01-01

Stream and river carbon dioxide emissions are an important component of the global carbon cycle. Methane emissions from streams could also contribute to regional or global greenhouse gas cycling, but there are relatively few data regarding stream and river methane emissions. Furthermore, the available data do not typically include the ebullitive (bubble-mediated) pathway, instead focusing on emission of dissolved methane by diffusion or convection. Here, we show the importance of ebullitive methane emissions from small streams in the regional greenhouse gas balance of a lake and wetland-dominated landscape in temperate North America and identify the origin of the methane emitted from these well-oxygenated streams. Stream methane flux densities from this landscape tended to exceed those of nearby wetland diffusive fluxes as well as average global wetland ebullitive fluxes. Total stream ebullitive methane flux at the regional scale (103 Mg C yr−1; over 6400 km2) was of the same magnitude as diffusive methane flux previously documented at the same scale. Organic-rich stream sediments had the highest rates of bubble release and higher enrichment of methane in bubbles, but glacial sand sediments also exhibited high bubble emissions relative to other studied environments. Our results from a database of groundwater chemistry support the hypothesis that methane in bubbles is produced in anoxic near-stream sediment porewaters, and not in deeper, oxygenated groundwaters. Methane interacts with other key elemental cycles such as nitrogen, oxygen, and sulfur, which has implications for ecosystem changes such as drought and increased nutrient loading. Our results support the contention that streams, particularly those draining wetland landscapes of the northern hemisphere, are an important component of the global methane cycle.

Influence of an aerobic sediment-water interface in relation to reduced risk of phosphorus leaching from re-established wetlands

DEFF Research Database (Denmark)

Forsmann, Ditte M.; Kjærgaard, Charlotte

water interactions are of fundamental importance for the biogeochemical processes controlling phosphorus dynamics in wetlands, and different hydrological pathways such as groundwater discharge and surface water flooding are operating within wetlands (Hoffmann et al., 2009). During groundwater discharge...... depends both on the hydrological regimes and the processes taking place at the sediment-water interface. Re-oxidation of iron might allow a recapturing of phosphorus (Zak et al., 2004), and thereby impede P losses to the aquatic environment....

Structure and dynamics of basin forested wetlands in North America

International Nuclear Information System (INIS)

Brown, S.

1990-01-01

Freshwater basin wetlands are found in depressions of various depths, generally in areas where precipitation exceeds evapotranspiration or where the depression intersects the water table creating groundwater seeps or springs. Forested basins are those that contain woody vegetation with the potential for reaching tree stature; they do not include woody shrub wetlands. In North America these areas are mainly in the central and eastern region. Pertinent information and reviews on the distribution, floristic composition, structure and dynamics of basin forested wetlands are summarized. The major emphasis is on freshwater wetlands, but data for saltwater wetlands mainly from Florida and tropical America are included. The external factors affecting basin wetlands or the important components of a wetlands energy signature are described as well as the distribution and floristic composition of representative basin wetlands. Sections on structural characteristics, organic matter dynamics, and nutrient cycling comprise the bulk of quantitative information. The effects of disturbances, both natural and human induced, with varying degrees of impact depending upon the intensity and on the part of the ecosystem to which the stressor is applied are evaluated. Examples of stressors in basin wetlands include water impoundment, water diversion, thermal stress from hot water, sedimentation, addition of toxic substances, addition of wastewater, oil spills, and harvesting. 86 refs., 5 figs., 11 tabs

Ecological patterns, diversity and core taxa of microbial communities in groundwater-fed rapid gravity filters

DEFF Research Database (Denmark)

Gülay, Arda; Musovic, Sanin; Albrechtsen, Hans-Jørgen

2016-01-01

Here, we document microbial communities in rapid gravity filtration units, specifically serial rapid sand filters (RSFs), termed prefilters (PFs) and after- filters (AFs), fed with anoxic groundwaters low in organic carbon to prepare potable waters. A comprehensive 16S rRNA-based amplicon...... sequencing survey revealed a core RSF microbiome comprising few bacterial taxa (29–30 genera) dominated by Nitrospirae, Proteobacteria and Acidobacteria, with a strikingly high abundance (75–87±18%) across five examined waterworks in Denmark. Lineages within the Nitrospira genus consistently comprised...... the second most and most abundant fraction in PFs (27±23%) and AFs (45.2±23%), respectively, and were far more abundant than typical proteobacterial ammonium-oxidizing bacteria, suggesting a physiology beyond nitrite oxidation for Nitrospira. Within the core taxa, sequences closely related to types...

Groundwater Discharge to Upper Barataria Basin Driven by Mississippi River Stage

Science.gov (United States)

Cable, J. E.; Kim, J.; Johannesson, K. H.; Kolker, A.; Telfeyan, K.; Breaux, A.

2017-12-01

Groundwater flow into deltaic wetlands occurs despite the heterogeneous and anisotropic depositional environment of deltas. Along the Mississippi River this groundwater flow is augmented by the vast alluvial aquifer and the levees which confine the river to a zone much more narrow than the historical floodplain. The effect of the levees has been to force the river stage to as much as 10 m above the adjacent back-levee wetlands. Consequently, the head difference created by higher river stages can drive groundwater flow into these wetlands, especially during flood seasons. We measured Rn-222 in the surface waters of a bayou draining a bottomland hardwood swamp in the lower Mississippi River valley over a 14-month period. With a half-life of 3.83 days and its conservative geochemical behavior, Rn-222 is a well-known tracer for groundwater inputs in both fresh and marine environments. Transects from the mouth to the headwaters of the bayou were monitored for Rn-222 in real-time using Rad-7s on a semi-monthly basis. We found that Rn-222 decreased exponentially from the swamp at the headwaters to the mouth of the bayou. Using a mass balance approach, we calculated groundwater inputs to the bayou headwaters and compared these discharge estimates to variations in Mississippi River stage. Groundwater inputs to the Barataria Basin, Louisiana, represent a significant fraction of the freshwater budget of the basin. The flow appears to occur through the sandy Point Bar Aquifer that lies adjacent to the river and underlies many of the freshwater swamps of the Basin. Tracer measurements throughout the Basin in these swamp areas appear to confirm our hypothesis about the outlet for groundwater in this deltaic environment.

Ground-survey and water-quality data for selected wetlands on or near the Lower Brule Indian Reservation in South Dakota, 2012-13

Science.gov (United States)

Neitzert, Kathleen M.; Thompson, Ryan F.

2015-08-20

Numerous lakes, ponds, and wetlands are located within the Lower Brule Indian Reservation. Wetlands are an important resource providing aquatic habitat for plants and animals, and acting as a natural water filtration system. Several of the wetlands on or near the reservation are of particular interest, but information on the physical and biological integrity of these wetlands was needed to provide a base-line reference when planning for future water management needs. A reconnaissance-level study of selected wetlands on and near the Lower Brule Indian Reservation was completed in 2012–13 by the U.S. Geological Survey in cooperation with the Lower Brule Sioux Tribe using ground surveys and water-quality analyses. Ground surveys of six wetland areas (Dorman Slough, Little Bend Wetlands, Miller Pond, Potter Slough, an unnamed slough, and West Brule Community wetlands) were completed to map land, water, vegetation, and man-made features of the selected wetland areas using real-time kinematic global navigation satellite systems equipment. Water samples were collected from four of the selected wetlands. Two separate waterbodies were sampled at one of the wetlands for a total of five sampling locations. Water samples were analyzed for physical properties, selected inorganics, metals, nutrients, and suspended sediment. Concentrations of calcium, sodium, and sulfate were greater at the two wetland sites fed by ground water, compared to the wetland sites fed by surface runoff.

Is nutrient contamination of groundwater causing eutrophication of groundwater-fed meadows?

NARCIS (Netherlands)

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

2005-01-01

There is an ongoing debate as to whether nutrient contamination of groundwater under agricultural fields may cause nutrient-enrichment and subsequent eutrophication in discharge areas. Often, there is only circumstantial evidence to support this supposition (proximity of agricultural fields,

Quantifying Spatially Integrated Floodplain and Wetland Systems for the Conterminous US

Science.gov (United States)

Lane, C.; D'Amico, E.; Wing, O.; Bates, P. D.

2017-12-01

Wetlands interact with other waters across a variable connectivity continuum, from permanent to transient, from fast to slow, and from primarily surface water to exclusively groundwater flows. Floodplain wetlands typically experience fast and frequent surface and near-surface groundwater interactions with their river networks, leading to an increasing effort to tailor management strategies for these wetlands. Management of floodplain wetlands is contingent on accurate floodplain delineation, and though this has proven challenging, multiple efforts are being made to alleviate this data gap at the conterminous scale using spatial, physical, and hydrological floodplain proxies. In this study, we derived and contrasted floodplain extents using the following nationally available approaches: 1) a geospatial-buffer floodplain proxy (Lane and D'Amico 2016, JAWRA 52(3):705-722, 2) a regionalized flood frequency analysis coupled to a 30m resolution continental-scale hydraulic model (RFFA; Smith et al. 2015, WRR 51:539-553), and 3) a soils-based floodplain analysis (Sangwan and Merwade 2015, JAWRA 51(5):1286-1304). The geospatial approach uses National Wetlands Inventory and buffered National Hydrography Datasets. RFFA estimates extreme flows based on catchment size, regional climatology and upstream annual rainfall and routes these flows through a hydraulic model built with data from USGS HydroSHEDS, NOAA, and the National Elevation Dataset. Soil-based analyses define floodplains based on attributes within the USDA soil-survey data (SSURGO). Nearly 30% (by count) of U.S. freshwater wetlands are located within floodplains with geospatial analyses, contrasted with 37% (soils-based), and 53% (RFFA-based). The dichotomies between approaches are mainly a function of input data-layer resolution, accuracy, coverage, and extent, further discussed in this presentation. Ultimately, these spatial analyses and findings will improve floodplain and integrated wetland system extent

Realizing ecosystem services: wetland hydrologic function along a gradient of ecosystem condition.

Science.gov (United States)

McLaughlin, Daniel L; Cohen, Matthew J

2013-10-01

Wetlands provide numerous ecosystem services, from habitat provision to pollutant removal, floodwater storage, and microclimate regulation. Delivery of particular services relies on specific ecological functions, and thus to varying degree on wetland ecological condition, commonly quantified as departure from minimally impacted reference sites. Condition assessments are widely adopted as regulatory indicators of ecosystem function, and for some services (e.g., habitat) links between condition and function are often direct. For others, however, links are more tenuous, and using condition alone to enumerate ecosystem value (e.g., for compensatory mitigation) may underestimate important services. Hydrologic function affects many services cited in support of wetland protection both directly (floodwater retention, microclimate regulation) and indirectly (biogeochemical cycling, pollutant removal). We investigated links between condition and hydrologic function to test the hypothesis, embedded in regulatory assessment of wetland value, that condition predicts function. Condition was assessed using rapid and intensive approaches, including Florida's official wetland assessment tool, in 11 isolated forested wetlands in north Florida (USA) spanning a land use intensity gradient. Hydrologic function was assessed using hydrologic regime (mean, variance, and rates of change of water depth), and measurements of groundwater exchange and evapotranspiration (ET). Despite a wide range in condition, no systematic variation in hydrologic regime was observed; indeed reference sites spanned the full range of variation. In contrast, ET was affected by land use, with higher rates in intensive (agriculture and urban) landscapes in response to higher leaf area. ET determines latent heat exchange, which regulates microclimate, a valuable service in urban heat islands. Higher ET also indicates higher productivity and thus carbon cycling. Groundwater exchange regularly reversed flow direction

Experimental and numerical study of the relation between flow paths and fate of a pesticide in a riparian wetland

Science.gov (United States)

Kidmose, Jacob; Dahl, Mette; Engesgaard, Peter; Nilsson, Bertel; Christensen, Britt S. B.; Andersen, Stine; Hoffmann, Carl Christian

2010-05-01

SummaryA field-scale pulse-injection experiment with the herbicide Isoproturon was conducted in a Danish riparian wetland. A non-reactive tracer (bromide) experiment was also carried out to characterize the physical transport system. Groundwater flow and reactive transport modelling was used to simulate flow paths, residence times, as well as bromide and Isoproturon distributions. The wetland can be characterized by two distinct riparian flow paths; one flow path discharges 2/3 of the incoming groundwater directly to the free water surface of the wetland near the foot of the hillslope with an average residence time of 205 days, and another flow path diffusively discharging the remaining 1/3 of the incoming groundwater to the stream with an average residence time of 425 days. The reactive transport simulations reveal that Isoproturon is retarded by a factor of 2-4, which is explained by the high organic content in the peat layer of the wetland. Isoproturon was found to be aerobically degraded with a half-life in the order of 12-80 days. Based on the quantification of flow paths, residence times and half-lives it is estimated that about 2/3 of the injected Isoproturon is removed in the wetland. Thus, close to 1/3 may find its way to the stream through overland flow. It is also possible that high concentrations of metabolites will reach the stream.

Differential responses of freshwater wetland soils to sulphate pollution

NARCIS (Netherlands)

Lamers, L.P.M.; Dolle, ten G.E.; Berg, van den S.T.G.; Delft, van S.P.J.; Roelofs, J.G.M.

2001-01-01

Sulphate (SO42-) reduction rates are generally low in freshwater wetlands and are regulated by the scarce availability of the ion. Increased concentrations of this electron acceptor due to sulphur (S) pollution of groundwater and surface water may, however, lead to high sulphate reduction rates now

Risk Perception and Vulnerability of Wetlands Areas on South ...

International Development Research Centre (IDRC) Digital Library (Canada)

Canadian specialists are contributing to research examining the risks to and vulnerability of wetland areas along the Atlantic coast of South America. These areas along the coastline protect ecosystems provide flood control, stabilize shorelines, replenish groundwater, and purify water. They also act as reservoirs of ...

A Model for Wetland Hydrology: Description and Validation

Science.gov (United States)

R.S. Mansell; S.A. Bloom; Ge Sun

2000-01-01

WETLANDS, a multidimensional model describing water flow in variably saturated soil and evapotranspiration, was used to simulate successfully 3-years of local hydrology for a cypress pond located within a relatively flat Coastal Plain pine forest landscape. Assumptions included negligible net regional groundwater flow and radially symmetric local flow impinging on a...

Transport of pesticides and artificial tracers in vertical-flow lab-scale wetlands

Science.gov (United States)

Durst, Romy; Imfeld, Gwenaël.; Lange, Jens

2013-01-01

Wetland systems can be hydrologically connected to a shallow aquifer and intercept upward flow of pesticide-contaminated water during groundwater discharge. However, pesticide transport and attenuation through wetland sediments (WSs) intercepting contaminated water is rarely evaluated quantitatively. The use of artificial tracers to evaluate pesticide transport and associated risks is a fairly new approach that requires evaluation and validation. Here we evaluate during 84 days the transport of two pesticides (i.e., isoproturon (IPU) and metalaxyl (MTX)) and three tracers (i.e., bromide (Br), uranine (UR), and sulforhodamine B (SRB)) in upward vertical-flow vegetated and nonvegetated lab-scale wetlands. The lab-scale wetlands were filled with outdoor WSs and were continuously supplied with tracers and the pesticide-contaminated water. The transport of IPU and UR was characterized by high solute recovery (approximately 80%) and low retardation compared to Br. The detection of desmethylisoproturon in the wetlands indicated IPU degradation. SRB showed larger retardation (>3) and lower recovery (approximately 60%) compared to Br, indicating that sorption controlled SRB transport. MTX was moderately retarded (approximately 1.5), and its load attenuation in the wetland reached 40%. In the vegetated wetland, preferential flow along the roots decreased interactions between solutes and sediments, resulting in larger pesticide and tracer recovery. Our results show that UR and IPU have similar transport characteristics under the tested subsurface-flow conditions, whereas SRB may serve as a proxy for less mobile and more persistent pesticides. Since UR and SRB are not significantly affected by degradation, their use as proxies for fast degrading pollutants may be limited. We anticipate our results to be a starting point for considering artificial tracers for investigating pesticide transport in environments at groundwater/surface-water interfaces.

Hydrogeochemistry of prairie pothole region wetlands: Role of long-term critical zone processes

Science.gov (United States)

Goldhaber, Martin B.; Mills, Christopher T.; Morrison, Jean M.; Stricker, Craig A.; Mushet, David M.; LaBaugh, James W.

2014-01-01

This study addresses the geologic and hydrogeochemical processes operating at a range of scales within the prairie pothole region (PPR). The PPR is a 750,000 km2portion of north central North America that hosts millions of small wetlands known to be critical habitat for waterfowl and other wildlife. At a local scale, we characterized the geochemical evolution of the 92-ha Cottonwood Lake study area (CWLSA), located in North Dakota, USA. Critical zone processes are the long-term determinant of wetland water and groundwater geochemistry via the interaction of oxygenated groundwater with pyrite in the underlying glacial till. Pyrite oxidation produced a brown, iron oxide-bearing surface layer locally over 13 m thick and an estimated minimum of 1.3 × 1010 g sulfate (SO42 −) at CWLSA. We show that the majority of this SO42− now resides in solid-phase gypsum (CaSO4•2H2O) and gypsum-saturated groundwater.

Event-Based Analysis of Rainfall-Runoff Response to Assess Wetland-Stream Interaction in the Prairie Pothole Region

Science.gov (United States)

Haque, M. A.; Ross, C.; Schmall, A.; Bansah, S.; Ali, G.

2016-12-01

Process-based understanding of wetland response to precipitation is needed to quantify the extent to which non-floodplain wetlands - such as Prairie potholes - generate flow and transmit that flow to nearby streams. While measuring wetland-stream (W-S) interaction is difficult, it is possible to infer it by examining hysteresis characteristics between wetland and stream stage during individual precipitation events. Hence, to evaluate W-S interaction, 10 intact and 10 altered/lost potholes were selected for study; they are located in Broughton's Creek Watershed (Manitoba, Canada) on both sides of a 5 km creek reach. Stilling wells (i.e., above ground wells) were deployed in the intact and altered wetlands to monitor surface water level fluctuations while water table wells were drilled below drainage ditches to a depth of 1 m to monitor shallow groundwater fluctuations. All stilling wells and water table wells were equipped with capacitance water level loggers to monitor fluctuations in surface water and shallow groundwater every 15 minutes. In 2013 (normal year) and 2014 (wet year), 15+ precipitation events were identified and scatter plots of wetland (x-axis) versus stream (y-axis) stage were built to identify W-S hysteretic dynamics. Initial data analysis reveals that in dry antecedent conditions, intact and altered wetlands show clockwise W-S relations, while drained wetlands show anticlockwise W-S hysteresis. However, in wetter antecedent conditions, all wetland types show anticlockwise hysteresis. Future analysis will target the identification of thresholds in antecedent moisture conditions that determine significant changes in event wetland response characteristics (e.g., the delay between the start of rainfall and stream stage, the maximum water level rise in each wetland during each event, the delay between the start of rainfall and peak wetland stage) as well as hysteresis properties (e.g., gradient and area of the hysteresis loop).

Assessment of arsenic content in soil, rice grains and groundwater and associated health risks in human population from Ropar wetland, India, and its vicinity.

Science.gov (United States)

Sharma, Sakshi; Kaur, Inderpreet; Nagpal, Avinash Kaur

2017-08-01

In the present study, potential health risks posed to human population from Ropar wetland and its vicinity, by consumption of inorganic arsenic (i-As) via arsenic contaminated rice grains and groundwater, were assessed. Total arsenic (t-As) in soil and rice grains were found in the range of 0.06-0.11 mg/kg and 0.03-0.33 mg/kg, respectively, on dry weight basis. Total arsenic in groundwater was in the range of 2.31-15.91 μg/L. i-As was calculated from t-As using relevant conversion factors. Rice plants were found to be arsenic accumulators as bioconcentration factor (BCF) was observed to be >1 in 75% of rice grain samples. Further, correlation analysis revealed that arsenic accumulation in rice grains decreased with increase in the electrical conductivity of soil. One-way ANOVA, cluster analysis and principal component analysis indicated that both geogenic and anthropogenic sources affected t-As in soil and groundwater. Hazard index and total cancer risk estimated for individuals from the study area were above the USEPA limits of 1.00 and 1.00 × 10 -6 , respectively. Kruskal-Wallis H test indicated that groundwater intake posed significantly higher health risk than rice grain consumption (χ 2 (1) = 17.280, p = 0.00003).

Using stable isotopes to understand hydrochemical processes in and around a Prairie Pothole wetland in the Northern Great Plains, USA

International Nuclear Information System (INIS)

Mills, Christopher T.; Goldhaber, Martin B.; Stricker, Craig A.; Holloway, JoAnn M.; Morrison, Jean M.; Ellefsen, Karl J.; Rosenberry, Donald O.; Thurston, Roland S.

2011-01-01

Highlights: → A stable isotope study of the hydrochemistry of a Prairie Pothole wetland system. → δ 18 O H2O and δ 2 H H2O values show salt concentration by transpiration at wetland edge. → A range of δ 34 S SO4 values indicate SO 4 source and reduction processes. → Isotopic mixing lines show interaction of surface and groundwater at wetland edge. - Abstract: Millions of internally drained wetland systems in the Prairie Potholes region of the northern Great Plains (USA and Canada) provide indispensable habitat for waterfowl and a host of other ecosystem services. The hydrochemistry of these systems is complex and a crucial control on wetland function, flora and fauna. Wetland waters can have high concentrations of SO 4 2- due to the oxidation of large amounts of pyrite in glacial till that is in part derived from the Pierre shale. Water chemistry including δ 18 O H2O , δ 2 H H2O , and δ 34 S SO4 values, was determined for groundwater, soil pore water, and wetland surface water in and around a discharge wetland in North Dakota. The isotopic data for the first time trace the interaction of processes that affect wetland chemistry, including open water evaporation, plant transpiration, and microbial SO 4 reduction.

A Physically-based Model for Predicting Soil Moisture Dynamics in Wetlands

Science.gov (United States)

Kalin, L.; Rezaeianzadeh, M.; Hantush, M. M.

2017-12-01

Wetlands are promoted as green infrastructures because of their characteristics in retaining and filtering water. In wetlands going through wetting/drying cycles, simulation of nutrient processes and biogeochemical reactions in both ponded and unsaturated wetland zones are needed for an improved understanding of wetland functioning for water quality improvement. The physically-based WetQual model can simulate the hydrology and nutrient and sediment cycles in natural and constructed wetlands. WetQual can be used in continuously flooded environments or in wetlands going through wetting/drying cycles. Currently, WetQual relies on 1-D Richards' Equation (RE) to simulate soil moisture dynamics in unponded parts of the wetlands. This is unnecessarily complex because as a lumped model, WetQual only requires average moisture contents. In this paper, we present a depth-averaged solution to the 1-D RE, called DARE, to simulate the average moisture content of the root zone and the layer below it in unsaturated parts of wetlands. DARE converts the PDE of the RE into ODEs; thus it is computationally more efficient. This method takes into account the plant uptake and groundwater table fluctuations, which are commonly overlooked in hydrologic models dealing with wetlands undergoing wetting and drying cycles. For verification purposes, DARE solutions were compared to Hydrus-1D model, which uses full RE, under gravity drainage only assumption and full-term equations. Model verifications were carried out under various top boundary conditions: no ponding at all, ponding at some point, and no rain. Through hypothetical scenarios and actual atmospheric data, the utility of DARE was demonstrated. Gravity drainage version of DARE worked well in comparison to Hydrus-1D, under all the assigned atmospheric boundary conditions of varying fluxes for all examined soil types (sandy loam, loam, sandy clay loam, and sand). The full-term version of DARE offers reasonable accuracy compared to the

Revisiting groundwater overdraft based on the experience of the Mancha Occidental Aquifer, Spain

Science.gov (United States)

Martínez-Santos, P.; Castaño-Castaño, S.; Hernández-Espriú, A.

2018-01-01

Aquifers provide a reliable freshwater source in arid and semiarid regions, where droughts are common and irrigated crops present significant water requirements, so intensive pumping is generally needed. Over-extraction leads to dropping water tables, which in turn threatens the survival of groundwater-dependent ecosystems and water supplies. This calls for strategies to channel hydrological, environmental, agricultural, political and social change. Based on the experience of the Mancha Occidental aquifer, Spain, this paper explores some of the complexities of managing groundwater, dealing with the long-term changes that intensive groundwater use has generated in the region. The Mancha experience shows how environmental conservation may drive social and economic change at the regional scale for periods spanning several decades. What makes this case study unique, however, is the combination of social and environmental conflicts, most of which stem from the prevalence of illegal water use, and their detrimental effect on Ramsar wetlands. The situation exposed a paradox, namely that subsidies for farmers to cut down on water use were actually detrimental to the welfare of groundwater-dependent ecosystems. The unexpected (and timely) occurrence of extreme rainfall events in recent times, after 40 years of ineffective management measures and sustained environmental degradation, enabled the aquifer and its associated wetlands to recover spectacularly to a near-pristine condition. As groundwater-dependent wetlands are highly sensitive ecosystems, it is concluded that it is up to society to decide how much environmental damage can be tolerated in exchange for the social and economic benefits of groundwater-based development.

Analysis of metolachlor ethane sulfonic acid chirality in groundwater: A tool for dating groundwater movement in agricultural settings

Science.gov (United States)

Chemical chirality of pesticides can be a useful tool for studying environmental processes. The chiral forms of metolachlor ethane sulfonic acid (MESA), an abundant metabolite of metolachlor, and metolachlor were examined over a 6 year period in groundwater and a groundwater-fed stream in a riparia...

Sustainable wetland management and support of ecosystem services

Science.gov (United States)

Smith, Loren M.; Euliss, Ned H.; Wilcox, Douglas A.; Brinson, Mark M.

2009-01-01

This article is a follow-up on a previous piece in the National Wetlands Newsletter in which we outlined problems associated with a static, local approach to wetland management versus an alternative that proposes a temporal and geomorphic approach (Euliss et al. 2009). We extend that concept by drawing on companion papers recently published in the journal Wetlands (Euliss et al. 2008, Smith et al. 2008). Here we highlight reasons for the failure of many managed wetlands to provide a suite of ecosystem services (e.g., carbon storage, diodiversity, ground-water recharge, contaminant filtering, floodwater storage). Our principal theme is that wetland management is best approached by giving consideration to the hydrogeomorphic processes that maintain productive ecosystems and by removing physical and social impediments to those processes. Traditional management actions are often oriented toward maintaining static conditions in wetlands without considering the temporal cycles that wetlands need to undergo or achieve productivity for specific groups of wildlife, such as waterfowl. Possibly more often, a manager's ability to influence hydrogeomorphic processes is restricted by activities in surrounding watersheds. These could be dams, for example, which do not allow management of flood-pulse processes essential to productivity of riparian systems. In most cases, sediments and nutrients associated with land use in contributing watersheds complicate management of wetlands for a suite of services, including wildlife. Economic or policy forces far-removed from a wetland often interact to prevent occurrence of basic ecosystem processes. Our message is consistent with recommendation of supply-side sustainability of Allen et al. (2002) in which ecosystems are managed "for the system that produces outputs rather than the outputs themselves."

Novel Mono-, Di-, and Trimethylornithine Membrane Lipids in Northern Wetland Planctomycetes

NARCIS (Netherlands)

Moore, E.K.; Hopmans, E.C.; Rijpstra, W.I.C.; Villanueva, L.; Dedysh, S.N.; Kulichevskaya, I.S.; Wienk, H.L.J.; Schoutsen, F.; Sinninghe Damsté, J.S.

2013-01-01

Northern peatlands represent a significant global carbon store and commonly originate from Sphagnum moss-dominated wetlands. These ombrotrophic ecosystems are rain fed, resulting in nutrient-poor, acidic conditions. Members of the bacterial phylum Planctomycetes are highly abundant and appear to

Spatial analysis of Carbon-14 dynamics in a wetland ecosystem (Duke Swamp, Chalk River Laboratories, Canada)

International Nuclear Information System (INIS)

Yankovich, T.L.; King-Sharp, K.J.; Carr, J.; Robertson, E.; Killey, R.W.D.; Beresford, N.A.; Wood, M.D.

2014-01-01

A detailed survey was conducted to quantify the spatial distribution of 14 C in Sphagnum moss and underlying soil collected in Duke Swamp. This wetland environment receives 14 C via groundwater pathways from a historic radioactive Waste Management Area (WMA) on Atomic Energy Canada Limited (AECL)'s Chalk River Laboratories (CRL) site. Trends in 14 C specific activities were evaluated with distance from the sampling location with the maximum 14 C specific activity (DSS-35), which was situated adjacent to the WMA and close to an area of groundwater discharge. Based on a spatial evaluation of the data, an east-to-west 14 C gradient was found, due to the influence of the WMA on 14 C specific activities in the swamp. In addition, it was possible to identify two groups of sites, each showing significant exponential declines with distance from the groundwater source area. One of the groups showed relatively more elevated 14 C specific activities at a given distance from source, likely due to their proximity to the WMA, the location of the sub-surface plume originating from the WMA, the presence of marsh and swamp habitat types, which facilitated 14 C transport to the atmosphere, and possibly, 14 C air dispersion patterns along the eastern edge of the swamp. The other group, which had lower 14 C specific activities at a given distance from the groundwater source area, included locations that were more distant from the WMA and the sub-surface plume, and contained fen habitat, which is known to act as barrier to groundwater flow. The findings suggest that proximity to source, groundwater flow patterns and habitat physical characteristics can play an important role in the dynamics of 14 C being carried by discharging groundwater into terrestrial and wetland environments. - Highlights: • Groundwater represents an important source of volatile radionuclides to wetlands. • Habitat type influenced 14 C transport from sub-surface to surface environments. • C-14 specific

Floodplain and Wetland Assessment for the Mortandad Wetland Enhancement and the DP Dissipater Projects at Los Alamos National Laboratory

Energy Technology Data Exchange (ETDEWEB)

Hathcock, Charles Dean [Los Alamos National Laboratory

2017-03-31

This floodplain and wetland assessment was prepared in accordance with 10 Code of Federal Regulations (CFR) 1022 Compliance with Floodplain and Wetland Environmental Review Requirements, which was promulgated to implement the U.S. Department of Energy (DOE) requirements under Executive Order 11988 Floodplain Management and Executive Order 11990 Wetlands Protection. According to 10 CFR 1022, a 100-year floodplain is defined as “the lowlands adjoining inland and coastal waters and relatively flat areas and flood prone areas of offshore islands” and a wetland is defined as “an area that is inundated or saturated by surface or groundwater at a frequency and duration sufficient to support, and that under normal circumstances does support, a prevalence of vegetation typically adapted for life in saturated soil conditions, including swamps, marshes, bogs, and similar areas.” In this action, DOE is proposing two projects to improve wetland and floodplain function at Los Alamos National Laboratory (LANL). The proposed work will comply with corrective action requirements under the Settlement Agreement and Stipulated Final Compliance Order (Settlement Agreement)1 Number HWB-14-20. The first project is located in Technical Areas (TA)-03 in upper Mortandad Canyon. The upper Mortandad wetlands have existing stormwater controls that need to be rehabilitated. Head-cut formation is occurring at the downstream portion of the wetland. This project will repair damages to the wetland and reduce the future erosion potential. The second project is located in TA-21 in Delta Prime (DP) Canyon. The intent of the DP Dissipater Project in DP Canyon is to install stormwater control structures in DP Canyon to retain low channel flows and reduce downstream sediment transport as well as peak flows during low and moderate storm events. Due to increased erosion, the stream bank in this area has unstable vertical walls within the stream channel. The DOE prepared this floodplain and wetland

Evaluation of Climate Change Impacts on Wetland Vegetation in the Dunhuang Yangguan National Nature Reserve in Northwest China Using Landsat Derived NDVI

Directory of Open Access Journals (Sweden)

Feifei Pan

2018-05-01

Full Text Available Based on 541 Landsat images between 1988 and 2016, the normalized difference vegetation indices (NDVIs of the wetland vegetation at Xitugou (XTG and Wowachi (WWC inside the Dunhuang Yangguan National Nature Reserve (YNNR in northwest China were calculated for assessing the impacts of climate change on wetland vegetation in the YNNR. It was found that the wetland vegetation at the XTG and WWC had both shown a significant increasing trend in the past 20–30 years and the increase in both the annual mean temperature and annual peak snow depth over the Altun Mountains led to the increase of the wetland vegetation. The influence of the local precipitation on the XTG wetland vegetation was greater than on the WWC wetland vegetation, which demonstrates that in extremely arid regions, the major constraint to the wetland vegetation is the availability of water in soils, which is greatly related to the surface water detention and discharge of groundwater. At both XTG and WWC, the snowmelt from the Altun Mountains is the main contributor to the groundwater discharge, while the local precipitation plays a lesser role in influencing the wetland vegetation at the WWC than at the XTG, because the wetland vegetation grows on a relatively flat terrain at the WWC, while it grows on a stream channel at the XTG.

Modeling the potential impacts of climate change on the water table level of selected forested wetlands in the southeastern United States

Science.gov (United States)

Zhu, Jie; Sun, Ge; Li, Wenhong; Zhang, Yu; Miao, Guofang; Noormets, Asko; McNulty, Steve G.; King, John S.; Kumar, Mukesh; Wang, Xuan

2017-12-01

The southeastern United States hosts extensive forested wetlands, providing ecosystem services including carbon sequestration, water quality improvement, groundwater recharge, and wildlife habitat. However, these wetland ecosystems are dependent on local climate and hydrology, and are therefore at risk due to climate and land use change. This study develops site-specific empirical hydrologic models for five forested wetlands with different characteristics by analyzing long-term observed meteorological and hydrological data. These wetlands represent typical cypress ponds/swamps, Carolina bays, pine flatwoods, drained pocosins, and natural bottomland hardwood ecosystems. The validated empirical models are then applied at each wetland to predict future water table changes using climate projections from 20 general circulation models (GCMs) participating in Coupled Model Inter-comparison Project 5 (CMIP5) under the Representative Concentration Pathways (RCPs) 4.5 and 8.5 scenarios. We show that combined future changes in precipitation and potential evapotranspiration would significantly alter wetland hydrology including groundwater dynamics by the end of the 21st century. Compared to the historical period, all five wetlands are predicted to become drier over time. The mean water table depth is predicted to drop by 4 to 22 cm in response to the decrease in water availability (i.e., precipitation minus potential evapotranspiration) by the year 2100. Among the five examined wetlands, the depressional wetland in hot and humid Florida appears to be most vulnerable to future climate change. This study provides quantitative information on the potential magnitude of wetland hydrological response to future climate change in typical forested wetlands in the southeastern US.

Modeling the potential impacts of climate change on the water table level of selected forested wetlands in the southeastern United States

Directory of Open Access Journals (Sweden)

J. Zhu

2017-12-01

Full Text Available The southeastern United States hosts extensive forested wetlands, providing ecosystem services including carbon sequestration, water quality improvement, groundwater recharge, and wildlife habitat. However, these wetland ecosystems are dependent on local climate and hydrology, and are therefore at risk due to climate and land use change. This study develops site-specific empirical hydrologic models for five forested wetlands with different characteristics by analyzing long-term observed meteorological and hydrological data. These wetlands represent typical cypress ponds/swamps, Carolina bays, pine flatwoods, drained pocosins, and natural bottomland hardwood ecosystems. The validated empirical models are then applied at each wetland to predict future water table changes using climate projections from 20 general circulation models (GCMs participating in Coupled Model Inter-comparison Project 5 (CMIP5 under the Representative Concentration Pathways (RCPs 4.5 and 8.5 scenarios. We show that combined future changes in precipitation and potential evapotranspiration would significantly alter wetland hydrology including groundwater dynamics by the end of the 21st century. Compared to the historical period, all five wetlands are predicted to become drier over time. The mean water table depth is predicted to drop by 4 to 22 cm in response to the decrease in water availability (i.e., precipitation minus potential evapotranspiration by the year 2100. Among the five examined wetlands, the depressional wetland in hot and humid Florida appears to be most vulnerable to future climate change. This study provides quantitative information on the potential magnitude of wetland hydrological response to future climate change in typical forested wetlands in the southeastern US.

Soil moisture prediction to support management in semiarid wetlands during drying episodes

NARCIS (Netherlands)

Aguilera, Héctor; Moreno, Luis; Wesseling, Jan G.; Jiménez-Hernández, María E.; Castaño, Silvino

2016-01-01

Wetlands supported by groundwater in semiarid regions are extremely vulnerable to the impacts of droughts, particularly anthropized systems. During drying periods, soil water content arises as the controlling factor for environmental and ecological disturbances such as the spread of invasive

Modeling the potential impacts of climate change on the water table level of selected forested wetlands in the southeastern United States

OpenAIRE

Zhu, Jie; Sun, Ge; Li, Wenhong; Zhang, Yu; Miao, Guofang; Noormets, Asko; McNulty, Steve G.; King, John S.; Kumar, Mukesh; Wang, Xuan

2017-01-01

The southeastern United States hosts extensive forested wetlands, providing ecosystem services including carbon sequestration, water quality improvement, groundwater recharge, and wildlife habitat. However, these wetland ecosystems are dependent on local climate and hydrology, and are therefore at risk due to climate and land use change. This study develops site-specific empirical hydrologic models for five forested wetlands with different characteristics by analyzing long-t...

Do geographically isolated wetlands influence landscape functions?

Science.gov (United States)

Cohen, Matthew J.; Creed, Irena F.; Alexander, Laurie C.; Basu, Nandita; Calhoun, Aram J.K.; Craft, Christopher; D’Amico, Ellen; DeKeyser, Edward S.; Fowler, Laurie; Golden, Heather E.; Jawitz, James W.; Kalla, Peter; Kirkman, L. Katherine; Lane, Charles R.; Lang, Megan; Leibowitz, Scott G.; Lewis, David Bruce; Marton, John; McLaughlin, Daniel L.; Mushet, David M.; Raanan-Kiperwas, Hadas; Rains, Mark C.; Smith, Lora; Walls, Susan C.

2015-01-01

Geographically isolated wetlands (GIWs), those surrounded by uplands, exchange materials, energy, and organisms with other elements in hydrological and habitat networks, contributing to landscape functions, such as flow generation, nutrient and sediment retention, and biodiversity support. GIWs constitute most of the wetlands in many North American landscapes, provide a disproportionately large fraction of wetland edges where many functions are enhanced, and form complexes with other water bodies to create spatial and temporal heterogeneity in the timing, flow paths, and magnitude of network connectivity. These attributes signal a critical role for GIWs in sustaining a portfolio of landscape functions, but legal protections remain weak despite preferential loss from many landscapes. GIWs lack persistent surface water connections, but this condition does not imply the absence of hydrological, biogeochemical, and biological exchanges with nearby and downstream waters. Although hydrological and biogeochemical connectivity is often episodic or slow (e.g., via groundwater), hydrologic continuity and limited evaporative solute enrichment suggest both flow generation and solute and sediment retention. Similarly, whereas biological connectivity usually requires overland dispersal, numerous organisms, including many rare or threatened species, use both GIWs and downstream waters at different times or life stages, suggesting that GIWs are critical elements of landscape habitat mosaics. Indeed, weaker hydrologic connectivity with downstream waters and constrained biological connectivity with other landscape elements are precisely what enhances some GIW functions and enables others. Based on analysis of wetland geography and synthesis of wetland functions, we argue that sustaining landscape functions requires conserving the entire continuum of wetland connectivity, including GIWs.

Experimental and numerical study of the relation between flow paths and fate of a pesticide in a riparian wetland

DEFF Research Database (Denmark)

Kidmose, Jacob Baarstrøm; Dahl, Mette; Engesgaard, Peter Knudegaard

2010-01-01

flow paths, residence times, as well as bromide and Isoproturon distributions. The wetland can be characterized by two distinct riparian flow paths; one flow path discharges 2/3 of the incoming groundwater directly to the free water surface of the wetland near the foot of the hillslope with an average...... residence time of 205days, and another flow path diffusively discharging the remaining 1/3 of the incoming groundwater to the stream with an average residence time of 425days. The reactive transport simulations reveal that Isoproturon is retarded by a factor of 2–4, which is explained by the high organic...

Assessing the cumulative impacts of geographically isolated wetlands on watershed hydrology using the SWAT model coupled with improved wetland modules.

Science.gov (United States)

Lee, S; Yeo, I-Y; Lang, M W; Sadeghi, A M; McCarty, G W; Moglen, G E; Evenson, G R

2018-06-07

Despite recognizing the importance of wetlands in the Coastal Plain of the Chesapeake Bay Watershed (CBW) in terms of ecosystem services, our understanding of wetland functions has mostly been limited to individual wetlands and overall catchment-scale wetland functions have rarely been investigated. This study is aimed at assessing the cumulative impacts of wetlands on watershed hydrology for an agricultural watershed within the Coastal Plain of the CBW using the Soil and Water Assessment Tool (SWAT). We employed two improved wetland modules for enhanced representation of physical processes and spatial distribution of riparian wetlands (RWs) and geographically isolated wetlands (GIWs). This study focused on GIWs as their hydrological impacts on watershed hydrology are poorly understood and GIWs are poorly protected. Multiple wetland scenarios were prepared by removing all or portions of the baseline GIW condition indicated by the U.S. Fish and Wildlife Service National Wetlands Inventory geospatial dataset. We further compared the impacts of GIWs and RWs on downstream flow (i.e., streamflow at the watershed outlet). Our simulation results showed that GIWs strongly influenced downstream flow by altering water transport mechanisms in upstream areas. Loss of all GIWs reduced both water routed to GIWs and water infiltrated into the soil through the bottom of GIWs, leading to an increase in surface runoff of 9% and a decrease in groundwater flow of 7% in upstream areas. These changes resulted in increased variability of downstream flow in response to extreme flow conditions. GIW loss also induced an increase in month to month variability of downstream flow and a decrease in the baseflow contribution to streamflow. Loss of all GIWs was shown to cause a greater fluctuation of downstream flow than loss of all RWs for this study site, due to a greater total water storage capacity of GIWs. Our findings indicate that GIWs play a significant role in controlling hydrological

Contraction and Expansion of the Upper Zambezi Wetlands in Response to Precipitation Regime Changes and Impacts on Carbon, Energy and Water Fluxes

Science.gov (United States)

Lowman, L.; Barros, A. P.

2017-12-01

The Upper Zambezi River Basin (UZRB) serves as the headwater catchment of the fourth-largest river in Africa, provides essential freshwater resources to arid and semi-arid regions within its boundaries, and recharges the Northern Kalahari Aquifer. Shallow and clayey soils give way to seasonal waterlogging, especially along drainage lines, favoring the establishment of wetlands. Woodland savanna, grasslands and miombo dominate the UZRB's diverse ecosystem, marking a complex transition zone between the Congo tropical rainforest and the Kalahari Desert that reflects spatial rainfall gradients. Satellite imagery shows that permanent wetlands are located in low-lying convergence zones in the northeast and northwest corners of UZRB where surface-groundwater interactions are most vigorous. However, orographic precipitation gradients cannot fully explain interannual changes in wetland area and vegetation density. We hypothesize that changes in vegetation density result from nonlinear interactions and feedbacks among precipitation, canopy biophysical properties, soil moisture and groundwater processes modulated by topography and regional hydrogeology. This work aims to understand how changes in vegetation density, particularly in and around permanent and intermittent wetlands, impact carbon, energy and water fluxes. Using the MODIS Nadir BRDF-Adjusted Reflectance product, a seasonally-varying wetland class is derived that reflects inter-annual precipitation and groundwater variability. The Duke Coupled Hydrology Model with Prognostic Vegetation is adapted to include C4 photosynthesis for the UZRB grasslands and used to simulate changes in canopy density and impacts on gross primary productivity, evapotranspiration, and soil moisture at high spatial and temporal resolution. Initial results using the column-wise model provide a baseline for understanding surface fluxes before incorporating groundwater and subsurface flows crucial to investigating the implicit nonlinearities

[Relationship between groundwater quality index of nutrition element and organic matter in riparian zone and water quality in river].

Science.gov (United States)

Hua-Shan, Xu; Tong-Qian, Zhao; Hong-Q, Meng; Zong-Xue, Xu; Chao-Hon, Ma

2011-04-01

Riparian zone hydrology is dominated by shallow groundwater with complex interactions between groundwater and surface water. There are obvious relations of discharge and recharge between groundwater and surface water. Flood is an important hydrological incident that affects groundwater quality in riparian zone. By observing variations of physical and chemical groundwater indicators in riparian zone at the Kouma section of the Yellow River Wetland, especially those took place in the period of regulation for water and sediment at the Xiaolangdi Reservoir, relationship between the groundwater quality in riparian zone and the flood water quality in the river is studied. Results show that there will be great risk of nitrogen, phosphorus, nitrate nitrogen and organic matter permeating into the groundwater if floodplain changes into farmland. As the special control unit of nitrogen pollution between rivers and artificial wetlands, dry fanning areas near the river play a very important role in nitrogen migration between river and groundwater. Farm manure as base fertilizer may he an important source of phosphorus leak and loss at the artificial wetlands. Phosphorus leaks into the groundwater and is transferred along the hydraulic gradient, especially during the period of regulation for water and sediment at the Xiaolangdi Reservoir. The land use types and farming systems of the riparian floodplain have a major impact on the nitrate nitrogen contents of the groundwater. Nitrogen can infiltrate and accumulate quickly at anaerobic conditions in the fish pond area, and the annual nitrogen achieves a relatively balanced state in lotus area. In those areas, the soil is flooded and at anaerobic condition in spring and summer, nitrogen infiltrates and denitrification significantly, but soil is not flooded and at aerobic condition in the autumn and winter, and during these time, a significant nitrogen nitrification process occurs. In the area between 50 m and 200 m from the river

The Exit Gradient As a Measure of Groundwater Dependency of Watershed Ecosystem Services

Science.gov (United States)

Faulkner, B. R.; Canfield, T. J.; Justin, G. F.

2014-12-01

Flux of groundwater to surface water is often of great interest for the determination of the groundwater dependency of ecosystem services, such as maintenance of wetlands and of baseflow as a contributor to stream channel storage. It is difficult to measure. Most methods are based on coarse mass balance estimates or seepage meters. One drawback of these methods is they are not entirely spatially explicit. The exit gradient is commonly used in engineering studies of hydraulic structures affected by groundwater flow. It can be simply defined in the groundwater modeling context as the ratio of the difference between the computed head and the land surface elevation, for each computational cell, to the thickness of the cell, as it varies in space. When combined with calibrated groundwater flow models, it also has the potential to be useful in watershed scale evaluations of groundwater dependency in a spatially explicit way. We have taken advantage of calibrated models for the Calapooia watershed, Oregon, to map exit gradients for the watershed. Streams in the Calapooia are hydraulically well connected with groundwater. Not surprisingly, we found large variations in exit gradients between wet and dry season model runs, supporting the notion of stream expansion, as observed in the field, which may have a substantial influence on water quality. We have mapped the exit gradients in the wet and dry seasons, and compared them to regions which have been mapped in wetland surveys. Those classified as Palustrine types fell largest in the area of contribution from groundwater. In many cases, substantially high exit gradients, even on average, did not correspond to mapped wetland areas, yet nutrient retention ecosystem services may still be playing a role in these areas. The results also reinforce the notion of the importance of baseflow to maintenance of stream flow, even in the dry summer season in this Temperate/Mediterranean climate. Exit gradient mapping is a simple, yet

Ground-Water Availability in the United States

Science.gov (United States)

Reilly, Thomas E.; Dennehy, Kevin F.; Alley, William M.; Cunningham, William L.

2008-01-01

Ground water is among the Nation's most important natural resources. It provides half our drinking water and is essential to the vitality of agriculture and industry, as well as to the health of rivers, wetlands, and estuaries throughout the country. Large-scale development of ground-water resources with accompanying declines in ground-water levels and other effects of pumping has led to concerns about the future availability of ground water to meet domestic, agricultural, industrial, and environmental needs. The challenges in determining ground-water availability are many. This report examines what is known about the Nation's ground-water availability and outlines a program of study by the U.S. Geological Survey Ground-Water Resources Program to improve our understanding of ground-water availability in major aquifers across the Nation. The approach is designed to provide useful regional information for State and local agencies who manage ground-water resources, while providing the building blocks for a national assessment. The report is written for a wide audience interested or involved in the management, protection, and sustainable use of the Nation's water resources.

Rates of BTEX Biodegradation under Nitrate Reducing Conditions in Wetland Sediments Impacted by Contaminated Groundwater

Science.gov (United States)

Olson, L. K.; McGuire, J. T.; Cozzarelli, I.; Smith, E. W.; Kneeshaw, T.

2010-12-01

Biodegradation rates are often controlled by dynamic interactions that occur at mixing interfaces between water masses of differing redox state. This study seeks to understand the controls on rates of BTEX (benzene, toluene, ethylbenzene and m,p,o-xylenes) degradation at a mixing interface by using in-situ experiments to simulate contaminated aquifer water containing nitrate discharging to a methanogenic wetland. BTEX biodegradation was evaluated during “dry” conditions (2009) and “wet” conditions (2010) in a shallow wetland near Bemidji, MN using innovative in-situ microcosms (ISMs) to measure rates of change over 8 weeks (2009) and 9 weeks (2010). ISM samplers contained an inner chamber filled with wetland sediments that were allowed to incubate for 2 weeks. This chamber was then closed to the surrounding environment and amended with test solution composed of contaminated groundwater augmented with tracer (bromide), nitrate and BTEX spike. Analysis of ISM sediments suggests that nitrate reduction and biodegradation rates are a function of both mineralogical and microbiological controls. Loss of nitrate, interpreted as nitrate reduction, was observed in both the dry and wet years with reduction slightly faster in the dry year (2.21mg/L/day versus 1.59 mg/L/day). Nitrate reduction was likely coupled to oxidation of various electron donors present in the system, including not only BTEX but also naturally occurring labile organic matter (ex. acetate) and inorganic electron donors (ex. Fe2+). BTEX degradation rates were considerably higher during the “wet” year than the “dry” year, with the fastest rates occurring immediately following test solution additions. For example, in the first 2 days of the “wet” ISM experiments degradation rates were 57.97ug/L/day for Benzene, 73.24ug/L/day for Toluene, 12.37ug/L/day for Ethyl Benzene and 85.61ug/L/day for Xylene compared to an ISM from the dry year which had slower degradation rates of 2.83ug/L/day for

Hydrogeological controls on spatial patterns of groundwater discharge in peatlands

Directory of Open Access Journals (Sweden)

D. K. Hare

2017-11-01

Full Text Available Peatland environments provide important ecosystem services including water and carbon storage, nutrient processing and retention, and wildlife habitat. However, these systems and the services they provide have been degraded through historical anthropogenic agricultural conversion and dewatering practices. Effective wetland restoration requires incorporating site hydrology and understanding groundwater discharge spatial patterns. Groundwater discharge maintains wetland ecosystems by providing relatively stable hydrologic conditions, nutrient inputs, and thermal buffering important for ecological structure and function; however, a comprehensive site-specific evaluation is rarely feasible for such resource-constrained projects. An improved process-based understanding of groundwater discharge in peatlands may help guide ecological restoration design without the need for invasive methodologies and detailed site-specific investigation. Here we examine a kettle-hole peatland in southeast Massachusetts historically modified for commercial cranberry farming. During the time of our investigation, a large process-based ecological restoration project was in the assessment and design phases. To gain insight into the drivers of site hydrology, we evaluated the spatial patterning of groundwater discharge and the subsurface structure of the peatland complex using heat-tracing methods and ground-penetrating radar. Our results illustrate that two groundwater discharge processes contribute to the peatland hydrologic system: diffuse lower-flux marginal matrix seepage and discrete higher-flux preferential-flow-path seepage. Both types of groundwater discharge develop through interactions with subsurface peatland basin structure, often where the basin slope is at a high angle to the regional groundwater gradient. These field observations indicate strong correlation between subsurface structures and surficial groundwater discharge. Understanding these general patterns

Hydrogeological controls on spatial patterns of groundwater discharge in peatlands

Science.gov (United States)

Hare, Danielle K.; Boutt, David F.; Clement, William P.; Hatch, Christine E.; Davenport, Glorianna; Hackman, Alex

2017-11-01

Peatland environments provide important ecosystem services including water and carbon storage, nutrient processing and retention, and wildlife habitat. However, these systems and the services they provide have been degraded through historical anthropogenic agricultural conversion and dewatering practices. Effective wetland restoration requires incorporating site hydrology and understanding groundwater discharge spatial patterns. Groundwater discharge maintains wetland ecosystems by providing relatively stable hydrologic conditions, nutrient inputs, and thermal buffering important for ecological structure and function; however, a comprehensive site-specific evaluation is rarely feasible for such resource-constrained projects. An improved process-based understanding of groundwater discharge in peatlands may help guide ecological restoration design without the need for invasive methodologies and detailed site-specific investigation. Here we examine a kettle-hole peatland in southeast Massachusetts historically modified for commercial cranberry farming. During the time of our investigation, a large process-based ecological restoration project was in the assessment and design phases. To gain insight into the drivers of site hydrology, we evaluated the spatial patterning of groundwater discharge and the subsurface structure of the peatland complex using heat-tracing methods and ground-penetrating radar. Our results illustrate that two groundwater discharge processes contribute to the peatland hydrologic system: diffuse lower-flux marginal matrix seepage and discrete higher-flux preferential-flow-path seepage. Both types of groundwater discharge develop through interactions with subsurface peatland basin structure, often where the basin slope is at a high angle to the regional groundwater gradient. These field observations indicate strong correlation between subsurface structures and surficial groundwater discharge. Understanding these general patterns may allow resource

A conceptual hydrologic model for a forested Carolina bay depressional wetland on the Coastal Plain of South Carolina, USA

Science.gov (United States)

Jennifer E. Pyzoha; Timothy J. Callahan; Ge Sun; Carl C. Trettin; Masato Miwa

2008-01-01

This paper describes how climate influences the hydrology of an ephemeral depressional wetland. Surface water and groundwater elevation data were collected for 7 years in a Coastal Plain watershed in South Carolina USA containing depressional wetlands, known as Carolina bays. Rainfall and temperature data were compared with water-table well and piezometer data in and...

Modeling of Soil Water and Salt Dynamics and Its Effects on Root Water Uptake in Heihe Arid Wetland, Gansu, China

Directory of Open Access Journals (Sweden)

Huijie Li

2015-05-01

Full Text Available In the Heihe River basin, China, increased salinity and water shortages present serious threats to the sustainability of arid wetlands. It is critical to understand the interactions between soil water and salts (from saline shallow groundwater and the river and their effects on plant growth under the influence of shallow groundwater and irrigation. In this study, the Hydrus-1D model was used in an arid wetland of the Middle Heihe River to investigate the effects of the dynamics of soil water, soil salinization, and depth to water table (DWT as well as groundwater salinity on Chinese tamarisk root water uptake. The modeled soil water and electrical conductivity of soil solution (ECsw are in good agreement with the observations, as indicated by RMSE values (0.031 and 0.046 cm3·cm−3 for soil water content, 0.037 and 0.035 dS·m−1 for ECsw, during the model calibration and validation periods, respectively. The calibrated model was used in scenario analyses considering different DWTs, salinity levels and the introduction of preseason irrigation. The results showed that (I Chinese tamarisk root distribution was greatly affected by soil water and salt distribution in the soil profile, with about 73.8% of the roots being distributed in the 20–60 cm layer; (II root water uptake accounted for 91.0% of the potential maximal value when water stress was considered, and for 41.6% when both water and salt stress were considered; (III root water uptake was very sensitive to fluctuations of the water table, and was greatly reduced when the DWT was either dropped or raised 60% of the 2012 reference depth; (IV arid wetland vegetation exhibited a high level of groundwater dependence even though shallow groundwater resulted in increased soil salinization and (V preseason irrigation could effectively increase root water uptake by leaching salts from the root zone. We concluded that a suitable water table and groundwater salinity coupled with proper irrigation

Model parameters for representative wetland plant functional groups

Science.gov (United States)

Williams, Amber S.; Kiniry, James R.; Mushet, David M.; Smith, Loren M.; McMurry, Scott T.; Attebury, Kelly; Lang, Megan; McCarty, Gregory W.; Shaffer, Jill A.; Effland, William R.; Johnson, Mari-Vaughn V.

2017-01-01

Wetlands provide a wide variety of ecosystem services including water quality remediation, biodiversity refugia, groundwater recharge, and floodwater storage. Realistic estimation of ecosystem service benefits associated with wetlands requires reasonable simulation of the hydrology of each site and realistic simulation of the upland and wetland plant growth cycles. Objectives of this study were to quantify leaf area index (LAI), light extinction coefficient (k), and plant nitrogen (N), phosphorus (P), and potassium (K) concentrations in natural stands of representative plant species for some major plant functional groups in the United States. Functional groups in this study were based on these parameters and plant growth types to enable process-based modeling. We collected data at four locations representing some of the main wetland regions of the United States. At each site, we collected on-the-ground measurements of fraction of light intercepted, LAI, and dry matter within the 2013–2015 growing seasons. Maximum LAI and k variables showed noticeable variations among sites and years, while overall averages and functional group averages give useful estimates for multisite simulation modeling. Variation within each species gives an indication of what can be expected in such natural ecosystems. For P and K, the concentrations from highest to lowest were spikerush (Eleocharis macrostachya), reed canary grass (Phalaris arundinacea), smartweed (Polygonum spp.), cattail (Typha spp.), and hardstem bulrush (Schoenoplectus acutus). Spikerush had the highest N concentration, followed by smartweed, bulrush, reed canary grass, and then cattail. These parameters will be useful for the actual wetland species measured and for the wetland plant functional groups they represent. These parameters and the associated process-based models offer promise as valuable tools for evaluating environmental benefits of wetlands and for evaluating impacts of various agronomic practices in

Drought induced pulses of SO42- from a Canadian shield wetland: use of δ34S and δ18O in SO42- to determine sources of sulfur

International Nuclear Information System (INIS)

Schiff, S.L.; Spoelstra, J.; Semkin, R.G.; Jeffries, D.S.

2005-01-01

Following summer drought periods, pulses of elevated SO 4 2- concentrations are frequently observed in streams draining forested catchments that contain wetlands. Delays in the recovery of freshwater streams and lakes in eastern Canada from historically high levels of acidic precipitation have been partially ascribed to these periodic pulses of SO 4 2- . Climate in eastern Canada has also changed within the last 25 a, with a documented increase in summer dryness and duration of droughts. In small forested catchments in the Turkey Lakes Watershed (TLW), SO 4 2- concentrations in streams draining wetlands can be elevated by up to a factor of 7 during post-drought discharge events compared to the annual average. Two neighbouring catchments, one with a series of cascading wetlands and one without any wetlands, were selected for comparison. Stable S and O isotope ratios were analyzed in samples of bulk precipitation, streams, and groundwaters to examine sources of SO 4 2- in post-drought pulses. δ 34 S-SO 4 2- in the streams and groundwaters show that SO 4 2- is retained in the wetland via SO 4 2- reduction and stored in the upper peat profile. Nitrate is elevated in soil and groundwaters at TLW due to high rates of nitrification in forest soils and the presence of NO 3 - can be used to identify piezometers unaffected by SO 4 2- reduction. δ 18 O-SO 4 2- shows that higher concentrations of SO 4 2- in deeper groundwater are likely due to oxidation of organic S and not a geologic source of reduced S. Following drought, the low δ 34 S-SO 4 2- in streams is consistent with wetland retention by SO 4 2- reduction and much lower than SO 4 2- released by weathering in deep glacial till and bedrock. High SO 4 2- groundwaters and geologic sources do not contribute to the SO 4 2- pulses in streams. Isotopic patterns over 6 a were similar. Pulses of SO 4 2- in the wetland catchments following drought are a result of the oxidation of S previously reduced and stored in the wetland

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.

Understanding the Hydrodynamics of a Coastal Wetland with an Integrated Distributed Model

Science.gov (United States)

Zhang, Y.; Li, W.; Sun, G.

2017-12-01

Coastal wetlands linking ocean and terrestrial landscape provide important ecosystem services including flood mitigation, fresh water supply, erosion control, carbon sequestration, and wildlife habitats. Wetland hydrology is the major driving force for wetland formation, structure, function, and ecosystem services. The dynamics of wetland hydrology and energy budget are strongly affected by frequent inundation and drying of wetland soil and vegetation due to tide, sea level rise (SLR) and climatic variability (change). However, the quantitative representation of how the energy budget and groundwater variation of coastal wetlands respond to frequent water level fluctuation is limited, especially at regional scales. This study developed a physically based distributed wetland hydrological model by integrating coastal processes and considering the inundation influence on energy budget and ET. Analysis using in situ measurements and satellite data for a coastal wetland in North Carolina confirm that the model sufficiently captures the wetland hydrologic behaviors. The validated model was then applied to examine the wetland hydrodynamics under a 30-year historical climate forcing (1985-2014) for the wetland region. The simulation reveals that 43% of the study area has inundation events, 63% of which has a frequency higher than 50% each year. The canopy evaporation and transpiration decline dramatically when the inundation level exceeds the canopy height. Additionally, inundation causes about 10% increase of the net shortwave radiation. This study also demonstrates that the critical wetland zones highly influenced by the coastal processes spans 300-800 m from the coastline. The model developed in the study offers a new tool for understanding the complex wetland hydrodynamics in response to natural and human-induced disturbances at landscape to regional scales.

WETLAND CHANGE DETECTION IN PROTECTED AND UNPROTECTED INDUS COASTAL AND INLAND DELTA

Directory of Open Access Journals (Sweden)

M. H. Ali Baig

2017-09-01

Full Text Available Worth of wetland sites lies in their ecological importance. They enhance ecosystem via provision of ecological services like improving water quality, groundwater infiltration, flood risk reduction and biodiversity regulation. Like other parts of the world Pakistan is also facing wetlands degradation. Ecological and economic significance of wetlands was recognized officially in 1971 as Pakistan became signatory of Ramsar wetland convention. Wetlands provide habitat to species of ecological and economic importance. Despite being recognized for international importance, Ramsar figures state that almost half of Pakistan’s wetlands are at moderate or prominent level threat. Wetlands ecosystems are deteriorating at a rapid rate, if uncontrolled this trend may lead to substantial losses. Therefore, management of these resources demands regular monitoring. Present study is dedicated to assessing levels of change overtime in three distinct types of wetlands in Pakistan i.e. Indus delta a coastal wetland, Uchhali complex an inland wetland which are both protected sites while another site Nurri Lagoon which is not sheltered under any category of protected areas. Remotely sensed data has remarkable applications in change detection. Multitemporal Landsat images were used to map changes occurring from 2006 to 2016. Results reveal that wetland area has considerably decreased for all types. Both protected sites have experienced degradation though impact is comparatively lesser than unprotected Nurri lagoon. Significance of protection strategies cannot be denied, it is recommended that mere declaration of a site protected area is not sufficient. It is equally important to control non-point pollutants and ensuring the compliance of conservation strategy.

Wetland Change Detection in Protected and Unprotected Indus Coastal and Inland Delta

Science.gov (United States)

Baig, M. H. Ali; Sultan, M.; Riaz Khan, M.; Zhang, L.; Kozlova, M.; Malik, N. Abbas; Wang, S.

2017-09-01

Worth of wetland sites lies in their ecological importance. They enhance ecosystem via provision of ecological services like improving water quality, groundwater infiltration, flood risk reduction and biodiversity regulation. Like other parts of the world Pakistan is also facing wetlands degradation. Ecological and economic significance of wetlands was recognized officially in 1971 as Pakistan became signatory of Ramsar wetland convention. Wetlands provide habitat to species of ecological and economic importance. Despite being recognized for international importance, Ramsar figures state that almost half of Pakistan's wetlands are at moderate or prominent level threat. Wetlands ecosystems are deteriorating at a rapid rate, if uncontrolled this trend may lead to substantial losses. Therefore, management of these resources demands regular monitoring. Present study is dedicated to assessing levels of change overtime in three distinct types of wetlands in Pakistan i.e. Indus delta a coastal wetland, Uchhali complex an inland wetland which are both protected sites while another site Nurri Lagoon which is not sheltered under any category of protected areas. Remotely sensed data has remarkable applications in change detection. Multitemporal Landsat images were used to map changes occurring from 2006 to 2016. Results reveal that wetland area has considerably decreased for all types. Both protected sites have experienced degradation though impact is comparatively lesser than unprotected Nurri lagoon. Significance of protection strategies cannot be denied, it is recommended that mere declaration of a site protected area is not sufficient. It is equally important to control non-point pollutants and ensuring the compliance of conservation strategy.

Groundwater and surface-water interaction and effects of pumping in a complex glacial-sediment aquifer, phase 2, east-central Massachusetts

Science.gov (United States)

Eggleston, Jack R.; Zarriello, Phillip J.; Carlson, Carl S.

2015-12-31

The U.S. Geological Survey, in cooperation with the Town of Framingham, Massachusetts, has investigated the potential of proposed groundwater withdrawals at the Birch Road well site to affect nearby surface water bodies and wetlands, including Lake Cochituate, the Sudbury River, and the Great Meadows National Wildlife Refuge in east-central Massachusetts. In 2012, the U.S. Geological Survey developed a Phase 1 numerical groundwater model of a complex glacial-sediment aquifer to synthesize hydrogeologic information and simulate potential future pumping scenarios. The model was developed with MODFLOW-NWT, an updated version of a standard USGS numerical groundwater flow modeling program that improves solution of unconfined groundwater flow problems. The groundwater model and investigations of the aquifer improved understanding of groundwater–surface-water interaction and the effects of groundwater withdrawals on surface-water bodies and wetlands in the study area. The initial work also revealed a need for additional information and model refinements to better understand this complex aquifer system.

Numerical simulation of groundwater and surface-water interactions in the Big River Management Area, central Rhode Island

Science.gov (United States)

Masterson, John P.; Granato, Gregory E.

2013-01-01

The Rhode Island Water Resources Board is considering use of groundwater resources from the Big River Management Area in central Rhode Island because increasing water demands in Rhode Island may exceed the capacity of current sources. Previous water-resources investigations in this glacially derived, valley-fill aquifer system have focused primarily on the effects of potential groundwater-pumping scenarios on streamflow depletion; however, the effects of groundwater withdrawals on wetlands have not been assessed, and such assessments are a requirement of the State’s permitting process to develop a water supply in this area. A need for an assessment of the potential effects of pumping on wetlands in the Big River Management Area led to a cooperative agreement in 2008 between the Rhode Island Water Resources Board, the U.S. Geological Survey, and the University of Rhode Island. This partnership was formed with the goal of developing methods for characterizing wetland vegetation, soil type, and hydrologic conditions, and monitoring and modeling water levels for pre- and post-water-supply development to assess potential effects of groundwater withdrawals on wetlands. This report describes the hydrogeology of the area and the numerical simulations that were used to analyze the interaction between groundwater and surface water in response to simulated groundwater withdrawals. The results of this analysis suggest that, given the hydrogeologic conditions in the Big River Management Area, a standard 5-day aquifer test may not be sufficient to determine the effects of pumping on water levels in nearby wetlands. Model simulations showed water levels beneath Reynolds Swamp declined by about 0.1 foot after 5 days of continuous pumping, but continued to decline by an additional 4 to 6 feet as pumping times were increased from a 5-day simulation period to a simulation period representative of long-term average monthly conditions. This continued decline in water levels with

Water-level fluctuation in wetlands as a function of landscape condition in the prairie pothole region

Science.gov (United States)

Euliss, Ned H.; Mushet, David M.

1996-01-01

We evaluated water-level fluctuation (maximum water depth - minimum water depth/catchment size) in 12 temporary, 12 seasonal, and 12 semipermanent wetlands equally distributed among landscapes dominated by tilled agricultural lands and landscapes dominated by grassland. Water levels fluctuated an average of 14.14 cm in wetlands within tilled agricultural landscapes, while water levels in wetlands within grassland landscapes fluctuated an average of only 4.27 cm. Tillage reduces the natural capacity of catch meets to mitigate surface flow into wetland basins during precipitation events, resulting in greater water-level fluctuations in wetlands with tilled catchments. In addition, water levels in temporary and seasonal wetlands fluctuated an average of 13.74 cm and 11.82 cm, respectively, while water levels in semipermanent wetlands fluctuated only 2.77 cm. Semipermanent wetlands receive a larger proportion of their water as input from ground water than do either temporary or seasonal wetlands. This input of water from the ground has a stabilizing effect on water-levels of semipermanent wetlands. Increases in water-level fluctuation due to tillage or due to alteration of ground-water hydrology may ultimately affect the composition of a wetland's flora and fauna. In this paper, we also describe an inexpensive device for determining absolute maximum and minimum water levels in wetlands.

Changing Groundwater and Lake Storage in the Americas from the Last Glacial Maximum to the Present Day

Science.gov (United States)

Callaghan, K. L.; Wickert, A. D.; Michael, L.; Fan, Y.; Miguez-Macho, G.; Mitrovica, J. X.; Austermann, J.; Ng, G. H. C.

2017-12-01

Groundwater accounts for 1.69% of the globe's water storage - nearly the same amount (1.74%) that is stored in ice caps and glaciers. The volume of water stored in this reservoir has changed over glacial-interglacial cycles as climate warms and cools, sea level rises and falls, ice sheets advance and retreat, surface topography isostatically adjusts, and patterns of moisture transport reorganize. During the last deglaciation, over the past 21000 years, all of these factors contributed to profound hydrologic change in the Americas. In North America, deglaciation generated proglacial lakes and wetlands along the isostatically-depressed margin of the retreating Laurentide Ice Sheet, along with extensive pluvial lakes in the desert southwest. In South America, changing patterns of atmospheric circulation caused regional and time-varying wetting and drying that led to fluctuations in water table levels. Understanding how groundwater levels change in response to these factors can aid our understanding of the effects of modern climate change on groundwater resources. Using a model that incorporates temporally evolving climate, topography (driven by glacial isostatic adjustment), ice extent, sea level, and spatially varying soil properties, we present our estimates of changes in total groundwater storage in the Americas over the past 21000 years. We estimate depth to water table at 500-year intervals and at a 30-arcsecond resolution. This allows a comparative assessment of changing groundwater storage volumes through time. The model has already been applied to the present day and has proven successful in estimating modern groundwater depths at a broad scale (Fan et al., 2013). We also assess changing groundwater-fed lakes, and compare model-estimated lake sizes and locations to paleorecords of these lakes. Our data- and model-integrated look back at the terminal Pleistocene provides an estimate of groundwater variability under extreme climate change. Preliminary results

Studying the impact of climate change on coastal aquifers and adjacent wetlands

Science.gov (United States)

Stigter, Tibor; Ribeiro, Luís.; Oliveira, Rodrigo; Samper, Javier; Fakir, Younes; Fonseca, Luís.; Monteiro, José Paulo; Nunes, João. Pedro; Pisani, Bruno

2010-05-01

program, assessing the impact of climate change on coastal groundwater resources and dependent ecosystems. These resources are often intensively exploited, potentially leading to saltwater intrusion and the degradation of groundwater and dependent wetlands. Climate change may increase this problem in Mediterranean regions, due to the combined effect of rising sea levels and decreasing aquifer recharge. CLIMWAT aims to address this problem by employing a multimethodological approach involving climate scenarios, surface and groundwater flow and transport modeling, as well as hydrochemical indicator and ecological diversity indices. Research is performed in three coastal areas: the Central Algarve in Portugal, the Ebro delta in Spain and the Atlantic Sahel in Morocco. The mean annual temperatures are 17.4 ° C, 17.2 ° C and 17.5 ° C, respectively, whereas mean annual rainfall is lower in the Atlantic Sahel (390 mm) than in the Ebro Delta (520 mm) and the Central Algarve (660 mm). Work package (WP) 1 involves the collection of existing data (in a GIS environment), baseline characterization and the selection of monitoring locations. These include wells and springs of official (water level/quality) monitoring networks, as well as additional observation points selected at strategic locations, including the wetlands receiving groundwater and adjacent aquifer sectors. In WP2 the climate scenarios are selected and integrated in hydrological models (SWAT, GISBALAN), which are developed and calibrated with existing data, prior to scenario modeling. The main focus of this WP is to estimate the evolution of surface runoff and groundwater recharge under climate change. Data on climate change scenarios and model projections are compiled from: (i) the PRUDENCE project; (ii) the ENSEMBLES project; (iii) IPCC scenarios and projections, AR4; (iv) AEMet (Spanish Meteorological Agency) for generation of regional scenarios of climate change in Spain. For Morocco, where runoff is

Is Groenvlei really fed by groundwater discharged from the Table ...

African Journals Online (AJOL)

Vankervelsvlei is a unique wetland located in the stabilised dunes east of Sedgefield. Groenvlei is one of a series of 5 brackish coastal lakes along the Southern Cape coast of South Africa, but is the only one disconnected from the sea. It has been hypothesised that discharge from the underlying Table Mountain Group ...

The effect of Littorella uniflora on nutrients in a groundwater fed lake

DEFF Research Database (Denmark)

Ommen, Daniela Oliveira; Vinther, Hanne Fogh; Krüger, Laila

into the lake; and a smaller recharge zone where water from the lake flows back into the aquifer. This variable groundwater pattern combined with only minor surface inlets and outlets provides good conditions for studying the interactions between groundwater and Littorella uniflora. Preliminary results from......Lake Hampen is a Lobelia lake situated high up in the Jutland ridge and which lies close to the groundwater boundary. This means that the groundwater flow between the aquifer and the lake is not constant. Lake Hampen has a large discharge zone where the groundwater flows from the aquifer......,49 to 0,88mg NO3-N L-1 in the recharge zone. There are also indications that the plants have the capability to effectively reduce high nitrate concentrations within the rhizosphere (reduction of 30 to 0,1mg NO3-N L-1 was observed)....

Fate of Uranium During Transport Across the Groundwater-Surface Water Interface

Energy Technology Data Exchange (ETDEWEB)

Jaffe, Peter R. [Princeton Univ., NJ (United States); Kaplan, Daniel I. [Savannah River Site (SRS), Aiken, SC (United States). Savannah River National Lab. (SRNL)

2017-06-30

Discharge of contaminated groundwater to surface waters is of concern at many DOE facilities. For example, at F-Area and TNX-Area on the Savannah River Site, contaminated groundwater, including uranium, is already discharging into natural wetlands. It is at this interface where contaminants come into contact with the biosphere. These this research addressed a critical knowledge gap focusing on the geochemistry of uranium (or for that matter, any redox-active contaminant) in wetland systems. Understanding the interactions between hydrological, microbial, and chemical processes will make it possible to provide a more accurate conceptual and quantitative understanding of radionuclide fate and transport under these unique conditions. Understanding these processes will permit better long-term management and the necessary technical justification for invoking Monitored Natural Attenuation of contaminated wetland areas. Specifically, this research did provide new insights on how plant-induced alterations to the sediment biogeochemical processes affect the key uranium reducing microorganisms, the uranium reduction, its spatial distribution, the speciation of the immobilized uranium, and its long-term stability. This was achieved by conducting laboratory mesocosm wetland experiments as well as field measurements at the SRNL. Results have shown that uranium can be immobilized in wetland systems. To a degree some of the soluble U(VI) was reduced to insoluble U(IV), but the majority of the immobilized U was incorporated into iron oxyhydroxides that precipitated onto the root surfaces of wetland plants. This U was immobilized mostly as U(VI). Because it was immobilized in its oxidized form, results showed that dry spells, resulting in the lowering of the water table and the exposure of the U to oxic conditions, did not result in U remobilization.

Nitrate attenuation in the Salburua wetland (Basque Country). Hydrogeological context; Atenuacion de nitratos en el Humedal de Salburua (Pais Vasco). Contexto hidrogeologico

Energy Technology Data Exchange (ETDEWEB)

Antiguedad, I.; Martinez-Santos, M.; Martinez, M.; Munoz, B.; Zabaleta, A.; Uriarte, J.; Morales, T.; Iribar, V.; Sanchez, J. M.; Ruiz, E.

2009-07-01

The Salburua wetland is located within a vulnerable zone (quaternary aquifer) related to the farming origin nitrate pollution. The restoration of the wetland, which was drained some decades ago, has evidenced the attenuation of nitrates in groundwater entering from farmlands, which exceed 50 mg/l NO{sub 3}. The recently installation of piezo metric network has allowed to characterize the groundwater flow pattern and determine the hydrogeological context of nitrate loss processes. Despite the dilution is happening the most important process seems to be the denitrification, either heterotrophic or auto trophic, probably depending on marly substratum position. The potential of denitrification has been measured in the soils and the values are really highs. This paper focuses on the right conditions for denitrification in the wetland. (Author) 23 refs.

Is Groenvlei really fed by groundwater discharged from the Table ...

African Journals Online (AJOL)

2009-05-15

May 15, 2009 ... Vankervelsvlei is a unique wetland located in the stabilised dunes east of Sedgefield. Groenvlei is one of a series of 5 brack- ish coastal lakes along the Southern Cape coast of South Africa, but is the only one disconnected from the sea. It has been hypothesised that discharge from the underlying Table ...

Groundwater in the hydrological functioning of wetlands in the Southeast of Buenos Aires Province, Argentina; El agua subterranea en el funcionamiento hidrologico de los humedales del Sudeste Bonaerense, Provincia de Buenos Aires, Argentina

Energy Technology Data Exchange (ETDEWEB)

Romanelli, A.; Quiroz, O.M.; Massone, H.E.; Martinez, D.E.; Bocanegra, E.

2010-07-01

The understanding of the hydrological functioning and the interaction among the different water bodies in an area is essential when a sustainable use of the hydric resources is considered. The hydrogeochemical interpretation of representative water-sample analyses is a useful tool developed for the analysis of hydrological systems. Isotopic techniques are also important tools for the validation and adjustment of conceptual hydrogeological models. The aim of the present paper is to develop depth of knowledge of the conceptual hydrogeological models for wetlands of the Pampa Plain by using hydrochemical and stable isotopic techniques. Three wetlands of different origin were sampled for hydrochemical and stable isotopic analysis (18O and 2H) at different depths. Groundwater and streams were also sampled. Hydrochemical analysis classified La Brava and Los Padres basins as sodium bicarbonate waters, and La Salada Basin as sodium chloride bicarbonate waters. Differences in the isotopic fingerprints and the electrical conductivity values were evident among wetlands: 6.766,8, 762,2 y 647,8 iS/cm in La Salada, Los Padres and La Brava respectively. Hydrochemical and isotopic data allowed us to define the effluent-influent behavior of these wetlands, their main recharge sources and their importance as aquifer recharge areas. (Author).

A review of the ecohydrology of the Sakumo wetland in Ghana.

Science.gov (United States)

Nonterah, Cynthia; Xu, Yongxin; Osae, Shiloh; Akiti, Thomas T; Dampare, Samuel B

2015-11-01

function. In order to protect the wetland structure and function, it is recommended that a determination for both surface water and groundwater (quality and quantity) components of the ecological reserve (aquatic ecosystem) as well as the basic human need should be undertaken. In addition, a complete hydrological study of the wetland must be done. This will enable a well-balanced water allocation scheme to all users while still ensuring long-term survival and sustainability of the wetland.

Effect of physico-chemical pretreatment on the removal efficiency of horizontal subsurface-flow constructed wetlands

Energy Technology Data Exchange (ETDEWEB)

Caselles-Osorio, Aracelly [Environmental Engineering Division, Hydraulics, Coastal and Environmental Engineering Department, Technical University of Catalonia, c/Jordi Girona 1-3, Modul D-1, 08034 Barcelona (Spain); Department of Biology, Atlantic University, Km 7 Higway Old Colombia Port, Barranquilla (Colombia); Garcia, Joan [Environmental Engineering Division, Hydraulics, Coastal and Environmental Engineering Department, Technical University of Catalonia, c/Jordi Girona 1-3, Modul D-1, 08034 Barcelona (Spain)]. E-mail: joan.garcia@upc.edu

2007-03-15

In this study, we tested the effect of a physico-chemical pretreatment on contaminant removal efficiency in two experimental horizontal subsurface-flow constructed wetlands (SSF CWs). One SSF CW was fed with settled urban wastewater, whereas the other with the same wastewater after it had undergone a physico-chemical pretreatment. The SSF CWs were operated with three different hydraulic retention times. During the experiments the effluent concentrations of COD, ammonia N and sulfate were very similar, and, therefore, the physico-chemical pretreatment did not improve the quality of the effluents. COD removal efficiency (as percentage or mass surface removal rate) was slightly greater in the SSF CW fed with pretreated wastewater. Ammonia N removal efficiency was, in general, similar in both SSF CWs and very high (80-90%). At the end of the experiments it was observed that in the SSF CW fed with settled wastewater the hydraulic conductivity decreased by a 20%. - A physico-chemical pretreatment may help to reduce the risk of clogging of subsurface-flow constructed wetlands.

Effect of physico-chemical pretreatment on the removal efficiency of horizontal subsurface-flow constructed wetlands

International Nuclear Information System (INIS)

Caselles-Osorio, Aracelly; Garcia, Joan

2007-01-01

In this study, we tested the effect of a physico-chemical pretreatment on contaminant removal efficiency in two experimental horizontal subsurface-flow constructed wetlands (SSF CWs). One SSF CW was fed with settled urban wastewater, whereas the other with the same wastewater after it had undergone a physico-chemical pretreatment. The SSF CWs were operated with three different hydraulic retention times. During the experiments the effluent concentrations of COD, ammonia N and sulfate were very similar, and, therefore, the physico-chemical pretreatment did not improve the quality of the effluents. COD removal efficiency (as percentage or mass surface removal rate) was slightly greater in the SSF CW fed with pretreated wastewater. Ammonia N removal efficiency was, in general, similar in both SSF CWs and very high (80-90%). At the end of the experiments it was observed that in the SSF CW fed with settled wastewater the hydraulic conductivity decreased by a 20%. - A physico-chemical pretreatment may help to reduce the risk of clogging of subsurface-flow constructed wetlands

Treatment Wetlands

OpenAIRE

Dotro, Gabriela; Langergraber, Günter; Molle, Pascal; Nivala, Jaime; Puigagut, Jaume; Stein, Otto; Von Sperling, Marcos

2017-01-01

Overview of Treatment Wetlands; Fundamentals of Treatment Wetlands; Horizontal Flow Wetlands; Vertical Flow Wetlands; French Vertical Flow Wetlands; Intensified and Modified Wetlands; Free Water Surface Wetlands; Other Applications; Additional Aspects.

Evidence for 20th century climate warming and wetland drying in the North American Prairie Pothole Region.

Science.gov (United States)

Werner, Brett A; Johnson, W Carter; Guntenspergen, Glenn R

2013-09-01

The Prairie Pothole Region (PPR) of North America is a globally important resource that provides abundant and valuable ecosystem goods and services in the form of biodiversity, groundwater recharge, water purification, flood attenuation, and water and forage for agriculture. Numerous studies have found these wetlands, which number in the millions, to be highly sensitive to climate variability. Here, we compare wetland conditions between two 30-year periods (1946-1975; 1976-2005) using a hindcast simulation approach to determine if recent climate warming in the region has already resulted in changes in wetland condition. Simulations using the WETLANDSCAPE model show that 20th century climate change may have been sufficient to have a significant impact on wetland cover cycling. Modeled wetlands in the PPR's western Canadian prairies show the most dramatic effects: a recent trend toward shorter hydroperiods and less dynamic vegetation cycles, which already may have reduced the productivity of hundreds of wetland-dependent species.

Evidence for 20th century climate warming and wetland drying in the North American Prairie Pothole Region

Science.gov (United States)

Werner, B.A.; Johnson, W. Carter; Guntenspergen, Glenn R.

2013-01-01

The Prairie Pothole Region (PPR) of North America is a globally important resource that provides abundant and valuable ecosystem goods and services in the form of biodiversity, groundwater recharge, water purification, flood attenuation, and water and forage for agriculture. Numerous studies have found these wetlands, which number in the millions, to be highly sensitive to climate variability. Here, we compare wetland conditions between two 30-year periods (1946–1975; 1976–2005) using a hindcast simulation approach to determine if recent climate warming in the region has already resulted in changes in wetland condition. Simulations using the WETLANDSCAPE model show that 20th century climate change may have been sufficient to have a significant impact on wetland cover cycling. Modeled wetlands in the PPR's western Canadian prairies show the most dramatic effects: a recent trend toward shorter hydroperiods and less dynamic vegetation cycles, which already may have reduced the productivity of hundreds of wetland-dependent species.

Global scale groundwater flow model

Science.gov (United States)

Sutanudjaja, Edwin; de Graaf, Inge; van Beek, Ludovicus; Bierkens, Marc

2013-04-01

As the world's largest accessible source of freshwater, groundwater plays vital role in satisfying the basic needs of human society. It serves as a primary source of drinking water and supplies water for agricultural and industrial activities. During times of drought, groundwater sustains water flows in streams, rivers, lakes and wetlands, and thus supports ecosystem habitat and biodiversity, while its large natural storage provides a buffer against water shortages. Yet, the current generation of global scale hydrological models does not include a groundwater flow component that is a crucial part of the hydrological cycle and allows the simulation of groundwater head dynamics. In this study we present a steady-state MODFLOW (McDonald and Harbaugh, 1988) groundwater model on the global scale at 5 arc-minutes resolution. Aquifer schematization and properties of this groundwater model were developed from available global lithological model (e.g. Dürr et al., 2005; Gleeson et al., 2010; Hartmann and Moorsdorff, in press). We force the groundwtaer model with the output from the large-scale hydrological model PCR-GLOBWB (van Beek et al., 2011), specifically the long term net groundwater recharge and average surface water levels derived from routed channel discharge. We validated calculated groundwater heads and depths with available head observations, from different regions, including the North and South America and Western Europe. Our results show that it is feasible to build a relatively simple global scale groundwater model using existing information, and estimate water table depths within acceptable accuracy in many parts of the world.

Using ion and isotope characterization to design a frame of protection of a wetland system (Massif Central, France)

International Nuclear Information System (INIS)

Brenot, Agnès; Négrel, Philippe; Millot, Romain; Bertin, Clotilde

2014-01-01

Highlights: • Multi-pronged approach demonstrated its effectiveness to improve wetland knowledge. • Chemical and multi-isotopic approaches trace water and dissolved-element fluxes. • Water volume flowing out of the peatland through the Fouragettes stream is negligible. • At least three strong groundwater fluxes supply water to the peatland. - Abstract: The bio-diversity (vegetation and fauna) of peatlands, like all wetland ecosystems, is very fragile as it requires specific wet conditions. Over the past 20 years, increasing efforts have been made to restore degraded wetlands, to re-create new wetlands where they were lost, and to sustainably manage for multiple benefits. However, actions to restore and preserve wetlands require an in-depth knowledge of the water cycle in the system. We used chemical and multi-isotopic approaches, combined with hydrological tools (measuring potentiometric levels and spring discharge), for tracing the water and dissolved-element fluxes in the Narces de la Sauvetat peatland (Central France) and for better understanding of water budget components involved in this ecosystem. This multi-pronged approach clearly demonstrated its effectiveness for improving our understanding of the hydrological functioning of this wetland ecosystem. The two main results are that: (1) The water volume flowing out of the peatland through the Fouragettes stream is often negligible; and (2) At least three strong groundwater fluxes with distinct chemical and isotopic signatures supply water to the peatland. This new understanding will help decision makers maintain the water balance of the peatland, which is essential for the preservation of this fragile ecosystem

Effect of seasonal drawdown variations on groundwater quality in ...

African Journals Online (AJOL)

user

2013-07-24

Jul 24, 2013 ... Igbinosa and Okoh (2009) reported the damaging conse- quences of leachate infiltration into groundwater bodies on life expectancy of such water consumers, while Quinn et al. (2006) enumerated its effect and that of delayed drawdown on moist plant productivity and wetland ecology. Several studies have ...

Simulation of the hydrogeologic effects of oil-shale mining on the neighbouring wetland water balance: case study in north-eastern Estonia

Science.gov (United States)

Marandi, Andres; Karro, Enn; Polikarpus, Maile; Jõeleht, Argo; Kohv, Marko; Hang, Tiit; Hiiemaa, Helen

2013-11-01

The water balance of wetlands plays an integral role in their function. Developments adjacent to wetlands can affect their water balance through impacts on groundwater flow and increased discharge in the area, and they can cause lowering of the wetland water table. A 430 km2 area was selected for groundwater modelling to asses the effect of underground mining on the water balance of wetlands in north-eastern Estonia. A nature conservation area (encompassing Selisoo bog) is within 3 km of an underground oil-shale mine. Two future mining scenarios with different areal extents of mining were modeled and compared to the present situation. Results show that the vertical hydraulic conductivity of the subsurface is of critical importance to potential wetland dewatering as a result of mining. Significant impact on the Selisoo bog water balance will be caused by the approaching mine but there will be only minor additional impacts from mining directly below the bog. The major impact will arise before that stage, when the underground mine extension reaches the border of the nature conservation area; since the restriction of activities in this area relates to the ground surface, the conservation area’s border is not sufficiently protective in relation to underground development.

Wetland influence on mercury fate and transport in a temperate forested watershed

International Nuclear Information System (INIS)

Selvendiran, Pranesh; Driscoll, Charles T.; Bushey, Joseph T.; Montesdeoca, Mario R.

2008-01-01

The transport and fate of mercury (Hg) was studied in two forest wetlands; a riparian peatland and an abandoned beaver meadow. The proportion of total mercury (THg) that was methyl mercury (% MeHg) increased from 2% to 6% from the upland inlets to the outlet of the wetlands. During the growing season, MeHg concentrations were approximately three times higher (0.27 ng/L) than values during the non-growing season (0.10 ng/L). Transport of Hg species was facilitated by DOC production as indicated by significant positive relations with THg and MeHg. Elevated concentrations of MeHg and % MeHg (as high as 70%) were found in pore waters of the riparian and beaver meadow wetlands. Groundwater interaction with the stream was limited at the riparian peatland due to the low hydraulic conductivity of the peat. The annual fluxes of THg and MeHg at the outlet of the watershed were 2.3 and 0.092 μg/m 2 -year respectively. - Wetlands are sources of THg and MeHg; the production of MeHg is seasonally dependent and driven by sulfate reduction in wetlands

Wetland influence on mercury fate and transport in a temperate forested watershed

Energy Technology Data Exchange (ETDEWEB)

Selvendiran, Pranesh [Department of Civil and Environmental Engineering, Syracuse University, Syracuse, NY 13244 (United States)], E-mail: pselvend@syr.edu; Driscoll, Charles T. [Department of Civil and Environmental Engineering, Syracuse University, Syracuse, NY 13244 (United States)], E-mail: ctdrisco@syr.edu; Bushey, Joseph T. [Department of Civil and Environmental Engineering, Syracuse University, Syracuse, NY 13244 (United States)], E-mail: jtbushey@syr.edu; Montesdeoca, Mario R. [Department of Civil and Environmental Engineering, Syracuse University, Syracuse, NY 13244 (United States)], E-mail: mmontesd@syr.edu

2008-07-15

The transport and fate of mercury (Hg) was studied in two forest wetlands; a riparian peatland and an abandoned beaver meadow. The proportion of total mercury (THg) that was methyl mercury (% MeHg) increased from 2% to 6% from the upland inlets to the outlet of the wetlands. During the growing season, MeHg concentrations were approximately three times higher (0.27 ng/L) than values during the non-growing season (0.10 ng/L). Transport of Hg species was facilitated by DOC production as indicated by significant positive relations with THg and MeHg. Elevated concentrations of MeHg and % MeHg (as high as 70%) were found in pore waters of the riparian and beaver meadow wetlands. Groundwater interaction with the stream was limited at the riparian peatland due to the low hydraulic conductivity of the peat. The annual fluxes of THg and MeHg at the outlet of the watershed were 2.3 and 0.092 {mu}g/m{sup 2}-year respectively. - Wetlands are sources of THg and MeHg; the production of MeHg is seasonally dependent and driven by sulfate reduction in wetlands.

Impact of water diversion on the hydrogeochemical characterization of surface water and groundwater in the Yellow River Delta

International Nuclear Information System (INIS)

Liu, Qiang; Li, Fadong; Zhang, Qiuying; Li, Jing; Zhang, Yan; Tu, Chun; Ouyang, Zhu

2014-01-01

Highlights: • We assess the response of different ecosystems to the water diversion. • We characterized the interaction between surface water and groundwater. • We use the Piper and HFE-D to illustrate the salinization process. - Abstract: The Yellow River Delta is undergoing severe ecosystem degradation through salinization caused mainly by seawater intrusion. The Yellow River diversion project, in operation since 2008, aims to mitigate a projected ecosystem disaster. We conducted field investigations across three ecosystems (Farmland, Wetland and Coast) in the delta to assess the effectiveness of the annual water pulse and determine the relationships between surface water and groundwater. The chemical characteristics of the groundwater in Farmland exclude the possibility of seawater intrusion. The Wetland is vulnerable to pollution by groundwater discharge from Farmland and to secondary salinization caused by rising water tables. The salinity values of groundwater at Coast sites likely reflect the presence of seawater trapped in the clay sediments, a premise corroborated through measurements of groundwater levels, stable isotopes and major ion signatures. Our δD–δ 18 O two-dimensional graphic plot demonstrated that groundwaters of Farmland and Wetland changed toward more depleted isotopic compositions following water diversion, but this was not the case in the Coast sites, where the water table varied little year-round. A hydrochemical facies evolution diagram (HFE-D) demonstrated that freshening is taking place in the largest portions of the aquifers and that, without sustained water diversion recharge, these underground water bodies may switch from freshening to salinization on a seasonal time scale. Thus, the qualities of waters in coastal aquifers in the Yellow River Delta are substantially influenced by the process of ecological water diversion, and also by land use practices and by the lithological properties of the drainage landscape

Constructing a Baseline Model of Alpine Wetlands of the Uinta Mountains, Utah, USA

Science.gov (United States)

Matyjasik, M.; Ford, R. L.; Bartholomew, L. M.; Welsh, S. B.; Hernandez, M.; Koerner, D.; Muir, M.

2008-12-01

Alpine wetlands of the Uinta Mountains, northeastern Utah, contain a variety of groundwater-dependent ecosystems. Unlike their counterparts in other areas of the Rocky Mountains, these systems have been relatively unstudied. The Reader Lakes area on the southern slope of the range was selected for detailed study because of its variety of wetland plant communities, homogenous bedrock geology, and minimal human impact. The primary goal of this interdisciplinary study is to establish the functional links between the geomorphology and hydrogeology of these high mountain wetlands and their constituent plant communities. In addition to traditional field studies and water chemistry, geospatial technologies are being used to organize and analyze both field data (water chemistry and wetland vegetation) and archived multispectral imagery (2006 NAIP images). The hydrology of these wetlands is dominated by groundwater discharge and their surface is dominated by string-and-flark morphology of various spatial scales, making these montane wetlands classic patterned fens. The drainage basin is organized into a series of large-scale stair-stepping wetlands, bounded by glacial moraines at their lower end. Wetlands are compartmentalized by a series of large strings (roughly perpendicular to the axial stream) and flarks. This pattern may be related to small ridges on the underlying ground moraine and possibly modified by beaver activity along the axial stream. Small-scale patterning occurs along the margins of the wetlands and in sloping-fen settings. The smaller-scale strings and flarks form a complex; self-regulating system in which water retention is enhanced and surface flow is minimized. Major plant communities have been identified within the wetlands for example: a Salix planifolia community associated with the peaty strings; Carex aquatilis, Carex limosa, and Eriophorum angustifolium communities associated with flarks; as well as a Sphagnum sp.- rich hummocky transition zone

The impact of pumped water from a de-watered Magnesian limestone quarry on an adjacent wetland: Thrislington, County Durham, UK

International Nuclear Information System (INIS)

Mayes, W.M.; Large, A.R.G.; Younger, P.L.

2005-01-01

Although quarrying is often cited as a potential threat to wetland systems, there is a lack of relevant, quantitative case studies in the literature. The impact of pumped groundwater discharged from a quarry into a wetland area was assessed relative to reference conditions in an adjacent fen wetland that receives only natural runoff. Analysis of vegetation patterns at the quarry wetland site, using Detrended Correspondence Analysis and the species indicator values of Ellenberg, revealed a clear disparity between community transitions in the quarry wetland and the reference site. Limited establishment of moisture-sensitive taxa, the preferential proliferation of robust wetland species and an overall shift towards lower species diversity in the quarry wetland were explicable primarily by the physico-chemical environment created by quarry dewatering. This encompassed high pH (up to 12.8), sediment-rich effluent creating a nutrient-poor substrate with poor moisture retention in the quarry wetland, and large fluctuations in water levels. - High pH, sediment-rich runoff from a quarry constrains floristic diversity in an adjacent wetland

The impact of pumped water from a de-watered Magnesian limestone quarry on an adjacent wetland: Thrislington, County Durham, UK

Energy Technology Data Exchange (ETDEWEB)

Mayes, W.M. [Institute for Research on Environment and Sustainability, University of Newcastle, Newcastle upon Tyne NE1 7RU (United Kingdom)]. E-mail: w.m.mayes@ncl.ac.uk; Large, A.R.G. [School of Geography, Politics and Sociology, University of Newcastle, Newcastle upon Tyne NE1 7RU (United Kingdom); Younger, P.L. [Institute for Research on Environment and Sustainability, University of Newcastle, Newcastle upon Tyne NE1 7RU (United Kingdom)

2005-12-15

Although quarrying is often cited as a potential threat to wetland systems, there is a lack of relevant, quantitative case studies in the literature. The impact of pumped groundwater discharged from a quarry into a wetland area was assessed relative to reference conditions in an adjacent fen wetland that receives only natural runoff. Analysis of vegetation patterns at the quarry wetland site, using Detrended Correspondence Analysis and the species indicator values of Ellenberg, revealed a clear disparity between community transitions in the quarry wetland and the reference site. Limited establishment of moisture-sensitive taxa, the preferential proliferation of robust wetland species and an overall shift towards lower species diversity in the quarry wetland were explicable primarily by the physico-chemical environment created by quarry dewatering. This encompassed high pH (up to 12.8), sediment-rich effluent creating a nutrient-poor substrate with poor moisture retention in the quarry wetland, and large fluctuations in water levels. - High pH, sediment-rich runoff from a quarry constrains floristic diversity in an adjacent wetland.

Water management can reinforce plant competition in salt-affected semi-arid wetlands

Science.gov (United States)

Coletti, Janaine Z.; Vogwill, Ryan; Hipsey, Matthew R.

2017-09-01

The diversity of vegetation in semi-arid, ephemeral wetlands is determined by niche availability and species competition, both of which are influenced by changes in water availability and salinity. Here, we hypothesise that ignoring physiological differences and competition between species when managing wetland hydrologic regimes can lead to a decrease in vegetation diversity, even when the overall wetland carrying capacity is improved. Using an ecohydrological model capable of resolving water-vegetation-salt feedbacks, we investigate why water surface and groundwater management interventions to combat vegetation decline have been more beneficial to Casuarina obesa than to Melaleuca strobophylla, the co-dominant tree species in Lake Toolibin, a salt-affected wetland in Western Australia. The simulations reveal that in trying to reduce the negative effect of salinity, the management interventions have created an environment favouring C. obesa by intensifying the climate-induced trend that the wetland has been experiencing of lower water availability and higher root-zone salinity. By testing alternative scenarios, we show that interventions that improve M. strobophylla biomass are possible by promoting hydrologic conditions that are less specific to the niche requirements of C. obesa. Modelling uncertainties were explored via a Markov Chain Monte Carlo (MCMC) algorithm. Overall, the study demonstrates the importance of including species differentiation and competition in ecohydrological models that form the basis for wetland management.

Use of hydrochemistry and environmental isotopes for evaluation of the hydrological connection between groundwater and wetland swamp Colombia

International Nuclear Information System (INIS)

Santa A, Diana P; Martinez F, Diana C; Betancur V, Teresita

2008-01-01

The understanding of water flow paths around a wetland is based on the hydrologic information interpretation. Although the incorporation of non-conventional techniques like hydrochemistry and isotopic hydrology allows a major compression level of hydrologic systems: They allow identify origin and evolution of water, movement times, permanence in the hydrologic cycle components. Cienaga Colombia wetland and its catch area, represent a strategic ecosystem located in the Bajo Cauca antioqueno. The natural conditions and the consequences of the human intervention on the wetland impose the need to approach its study and understanding, seeking to be able lo design effective measures to guarantee its sustainability. We presents the firsts results of the project developed by Antioquia University and IAEA: Hydrochemical and Isotopic techniques for the assessment of hydrological processes in the wetlands of Bajo Cauca Antioqueno which is part of the program: Isotopic techniques for assessment of hydrological processes in wetlands by International Atomic Energy Agency, IAEA. The general objective of the study is evaluate the dynamic of water flow, in and out of the wetland in the Bajo Cauca Antioqueno, using geochemical and isotopic techniques.

Operational, design and microbial aspects related to power production with microbial fuel cells implemented in constructed wetlands.

Science.gov (United States)

Corbella, Clara; Guivernau, Miriam; Viñas, Marc; Puigagut, Jaume

2015-11-01

This work aimed at determining the amount of energy that can be harvested by implementing microbial fuel cells (MFC) in horizontal subsurface constructed wetlands (HSSF CWs) during the treatment of real domestic wastewater. To this aim, MFC were implemented in a pilot plant based on two HSSF CW, one fed with primary settled wastewater (Settler line) and the other fed with the effluent of a hydrolytic up-flow sludge blanket reactor (HUSB line). The eubacterial and archaeal community was profiled on wetland gravel, MFC electrodes and primary treated wastewater by means of 16S rRNA gene-based 454-pyrosequencing and qPCR of 16S rRNA and mcrA genes. Maximum current (219 mA/m(2)) and power (36 mW/m(2)) densities were obtained for the HUSB line. Power production pattern correlated well with water level fluctuations within the wetlands, whereas the type of primary treatment implemented had a significant impact on the diversity and relative abundance of eubacteria communities colonizing MFC. It is worth noticing the high predominance (13-16% of relative abundance) of one OTU belonging to Geobacter on active MFC of the HUSB line that was absent for the settler line MFC. Hence, MFC show promise for power production in constructed wetlands receiving the effluent of a HUSB reactor. Copyright © 2015 Elsevier Ltd. All rights reserved.

A review of visual MODFLOW applications in groundwater modelling

Science.gov (United States)

Hariharan, V.; Shankar, M. Uma

2017-11-01

Visual MODLOW is a Graphical User Interface for the USGS MODFLOW. It is a commercial software that is popular among the hydrogeologists for its user-friendly features. The software is mainly used for Groundwater flow and contaminant transport models under different conditions. This article is intended to review the versatility of its applications in groundwater modelling for the last 22 years. Agriculture, airfields, constructed wetlands, climate change, drought studies, Environmental Impact Assessment (EIA), landfills, mining operations, river and flood plain monitoring, salt water intrusion, soil profile surveys, watershed analyses, etc., are the areas where the software has been reportedly used till the current date. The review will provide a clarity on the scope of the software in groundwater modelling and research.

Groundwater age and chemistry, and future nutrient loads for selected Rotorua Lakes catchments

International Nuclear Information System (INIS)

Morgenstern, U.; Reevers, R.R.; Daugney, C.J.; Cameron, S.; Gordon, D.

2005-01-01

Hydrochemical analysis and age dating of groundwater and groundwater-fed streams were carried out in the Lake Rotorua and Okareka catchments to assess the past and current states, and future trends in groundwater chemistry. The study was undertaken because of declining lake water quality due to observed increases in nutrient loads entering these lakes. THe hydrogeology of the Rotorua Lakes area can be described as a permeable pumiceous surface tephra layer that allows easy penetration of rainwater recharge to deeper rhyolite and ignimbrite aquifers. These aquifers are essentially unconfined and yield high volumes of groundwater that discharges to spring-fed streams or directly to the lake. The hydrochemistry of groundwaters is characterised by much lower concentrations of Ca, Mg and SO 4 and much higher concentrations of PO 4 -P and SiO 2 than other groundwaters in New Zealand. This chemical signature reflects the volcanic origin of the aquifer lithology. Because the aquifers in the Rotorua area have large water storage capacity there is a long residence time for nutrient-laden groundwater. It takes decades for the water after being recharged to reach the spring-fed streams and the lakes. The large groundwater bodies have therefore 'silently' been contaminated over decades, with the old pristine groundwater being progressively replaced by younger nutrient-laden water that will discharge to the spring-fed streams and finally to the lakes. This study involved age dating of springs, wells, and groundwater-fed streams to assess how long it takes for nutrient-enriched groundwater to travel from pastoral land to springs and streams, and to the lakes. Most of the springs and wells in the Lake Rotorua and Okareka catchments contained relatively old groundwaters, with mean residence times between 40 and >170 years (only two wells have younger water of 26 and 31 years mean residence time). This corresponds to young water fractions (water recharged within the last 55 years

Diversity and composition of sediment bacteria in subtropical coastal wetlands of North Stradbroke Island, Queensland, Australia

Science.gov (United States)

Chuvochina, Maria; Sampayo, Eugenia; Welti, Nina; Hayes, Matthew; Lu, Yang; Lovelock, Catherine; Lockington, David

2013-04-01

Coastal wetlands provide a wide variety of important ecosystem services but continue to suffer disturbance, degradation and deforestation. Sediment bacteria are responsible for major nutrient transformation and recycling in these ecosystems. Insight into microbial community composition and the factors that determine them may improve our understanding of biogeochemical processes, food web dynamics, biodegradation processes and, thus, help to develop the management strategies for preserving the ecosystem health and services. Characterizing shifts in community taxa along environmental gradients has been shown to provide a useful tool for determining the major drivers affecting community structure and function. North Stradbroke Island (NSI) in Southern Queensland presents considerable habitat diversity including variety of groundwater dependent ecosystems such as lakes, swamps, sedge-like salt marshes and mangroves. Ecological responses of continuous groundwater extraction for municipal purposes and sand mining operations on NSI are still need to be assessed in order to protect its unique environment. Changes in coastal hydrology due to either climate change or human activity may directly affect microbial populations and, thus, biogeochemical cycles of nutrients. These may result in altering/losing some ecosystem services provided by coastal wetlands. In this study we examine microbial diversity and determine environmental controls on bacterial community structure along a natural transition from freshwater forested wetland (melaleuca woodland), sedge-like salt marsh and into mangroves located at NSI. The study area is characterized by significant groundwater flow, nutrient limitation and sharp transition from one ecosystem type to another. Sediment cores (0-5 cm and 20-25 cm depth) were collected from three representative sites of each zone (mangroves - salt marsh - freshwater wetland) along the salinity gradient in August 2012. Subsamples were set aside for use in

Wonderful Wetlands: An Environmental Education Curriculum Guide for Wetlands.

Science.gov (United States)

King County Parks Div., Redmond, WA.

This curriculum guide was designed to give teachers, students, and society a better understanding of wetlands in the hope that they learn why wetlands should be valued and preserved. It explores what is meant by wetlands, functions and values of wetlands, wetland activities, and wetland offerings which benefit animal and plant life, recreation,…

Desert wetlands in the geologic record

Science.gov (United States)

Pigati, Jeff S.; Rech, Jason A.; Quade, Jay; Bright, Jordon; Edwards, L.; Springer, A.

2014-01-01

Desert wetlands support flora and fauna in a variety of hydrologic settings, including seeps, springs, marshes, wet meadows, ponds, and spring pools. Over time, eolian, alluvial, and fluvial sediments become trapped in these settings by a combination of wet ground conditions and dense plant cover. The result is a unique combination of clastic sediments, chemical precipitates, and organic matter that is preserved in the geologic record as ground-water discharge (GWD) deposits. GWD deposits contain information on the timing and magnitude of past changes in water-table levels and, therefore, are a potential source of paleohydrologic and paleoclimatic information. In addition, they can be important archeological and paleontological archives because desert wetlands provide reliable sources of fresh water, and thus act as focal points for human and faunal activities, in some of the world's harshest and driest lands. Here, we review some of the physical, sedimentological, and geochemical characteristics common to GWD deposits, and provide a contextual framework that researchers can use to identify and interpret geologic deposits associated with desert wetlands. We discuss several lines of evidence used to differentiate GWD deposits from lake deposits (they are commonly confused), and examine how various types of microbiota and depositional facies aid in reconstructing past environmental and hydrologic conditions. We also review how late Quaternary GWD deposits are dated, as well as methods used to investigate desert wetlands deeper in geologic time. We end by evaluating the strengths and limitations of hydrologic and climatic records derived from GWD deposits, and suggest several avenues of potential future research to further develop and utilize these unique and complex systems.

Hydrology and Ecology of Freshwater Wetlands in Central Florida - A Primer

Science.gov (United States)

Haag, Kim H.; Lee, Terrie M.

2010-01-01

Freshwater wetlands are an integral part of central Florida, where thousands are distributed across the landscape. However, their relatively small size and vast numbers challenge efforts to characterize them collectively as a statewide water resource. Wetlands are a dominant landscape feature in Florida; in 1996, an estimated 11.4 million acres of wetlands occupied 29 percent of the area of the State. Wetlands represent a greater percentage of the land surface in Florida than in any other state in the conterminous United States. Statewide, 90 percent of the total wetland area is freshwater wetlands and 10 percent is coastal wetlands. About 55 percent of the freshwater wetlands in Florida are forested, 25 percent are marshes and emergent wetlands, 18 percent are scrub-shrub wetlands, and the remaining 2 percent are freshwater ponds. Freshwater wetlands are distributed differently in central Florida than in other parts of the State. In the panhandle and in northern Florida, there are fewer isolated wetlands than in the central and southern parts of the State, and few of those wetlands are affected by activities such as groundwater withdrawals. In southern Florida, the vast wetlands of the Everglades and the Big Cypress Swamp blanket the landscape and form contiguous shallow expanses of water, which often exhibit slow but continuous flow toward the southwestern coast. In contrast, the wetlands of central Florida are relatively small, numerous, mostly isolated, and widely distributed. In many places, wetlands are flanked by uplands, generating a mosaic of contrasting environments-unique wildlife habitat often adjacent to dense human development. As the population of central Florida increases, the number of residents living near wetlands also increases. Living in close proximity to wetlands provides many Floridians with an increased awareness of nature and an opportunity to examine the relationship between people and wetlands. Specifically, these residents can observe

Wetlands for the remediation of BTEX [benzene, toluene, ethylbenzene, xylenes] contamination: Amalgamation of policy and technology

International Nuclear Information System (INIS)

Main, C.J.

1993-01-01

The fate and transport of benzene, toluene, ethylbenzene, and xylenes (BTEX) as they pass from a groundwater to a surface water environment was studied in three separate field experiments. The first examined the fate of BTEX from a spilled gasoline plume as it travelled vertically in the groundwater flow regime from a mineral soil unit through an organic soil unit to a surface wetland. The second considered surface water processes in the swamp that result in losses of BTEX concentrations. The final experiment evaluated the effects of seasonal and temporal changes on the processes occurring in the swamp that affect the fate and transport of BTEX under natural flow conditions. Significant reductions in BTEX were observed as the plume travelled vertically to reach the surface water. Reductions in contaminant levels were primarily due to sorption and biodegradation. On reaching the surface, overall reduction of compound concentration over 6 m of horizontal flow ranged from 92% for benzene to 85% for m-xylene. BTEX losses were mainly due to dilution, volatilization, and sorption. Limitations existing in the approach taken by present legislation and guidelines for wetland protection are discussed. Reactive legislation and guidelines should allow natural remediation of contamination in wetlands to be considered, especially when contaminant remediation requires alteration of the hydrologic flow regime or removal of contaminated material that may result in elimination of the wetland. 70 refs., 20 figs., 14 tabs

Recent Advances in the Area of Groundwater

Science.gov (United States)

Bahr, J. M.

2017-12-01

Groundwater related papers published in Water Resources Research in the last year range from experimental and modeling studies of pore scale flow and reactive transport to assessments of changes in water storage at the scale of regional aquifers enabled by satellite observations. Important societal needs motivating these studies include sustainability of groundwater resources of suitable quantity and quality for human use, protection of groundwater-dependent ecosystems in streams, wetlands, lakes and coastal areas, and assessment of the feasibility of subsurface sequestration of carbon dioxide and long-lived radioactive wastes. Eight general areas that generated ten or more papers within the period July 2016 to June 2017 are the following: aquifer heterogeneity (including geostatistical and inverse methods for parameter estimation), flow and transport in the unsaturated zone (including recharge to and evaporative losses from aquifers), multiphase flow and transport (including processes relevant to carbon sequestration), groundwater-surface water interactions (particularly hyporheic exchange), flow and transport in fractured media, novel remote sensing and geophysical techniques for aquifer characterization and assessment of groundwater dynamics, freshwater-saltwater interactions (particularly in coastal aquifers), and reactive solute transport. This presentation will highlight selected findings in each of these areas.

Co-regulation of redox processes in freshwater wetlands as a function of organic matter availability?

International Nuclear Information System (INIS)

Alewell, C.; Paul, S.; Lischeid, G.; Storck, F.R.

2008-01-01

Wetlands have important filter functions in landscapes but are considered to be the biggest unknowns regarding their element dynamics under global climate change. Information on sink and source function of sulphur, nitrogen, organic matter and acidity in wetlands is crucial for freshwater regeneration. Recent results indicate that redox processes are not completely controlled by the sequential reduction chain (that is electron acceptor availability) but that electron donor availability may be an important regulator. Our hypothesis was that only sites which are limited in their electron donor availability (low concentrations of dissolved organic carbon (DOC)) follow the concept of the sequential reduction chain. We compared the results of two freshwater wetland systems: 1) three forested fens within a boreal spruce catchment in a low mountain range in southern Germany (high DOC regime) and 2) three floodplain soils within a groundwater enrichment area in the Rhein valley in northwest Switzerland (low DOC regime). Micro scale investigations (a few cm 3 ) with dialyse chambers as well as soil solution and groundwater concentrations at the forested fens (high DOC regime) indicated simultaneous consumption of nitrate and sulphate with release of iron, manganese and methane (CH 4 ) as well as an enrichment in stable sulphur isotopes indicating a co-existence of processes attributed to different redox gradients. Soil and aquifer gas measurements down to 4.6 m at the groundwater enrichment site (low DOC regime and carbon limitation) showed extreme high rates of metabolism with carbon dioxide (CO 2 ) , dinitrous oxide (N 2 O) and CH 4 concentrations reaching fifty, thirty and three times atmospheric concentrations, respectively. Simultaneously, groundwater oxygen (O 2 ) saturation was between 50 and 95%. We concluded that independent of DOC regime the sequential reduction chain was not a suitable concept in our systems. Instead of electron acceptor or donor availability

Baseline ecological risk assessment and remediation alternatives for a hydrocarbon-contaminated estuarine wetland

International Nuclear Information System (INIS)

Vedagiri, U.

1993-01-01

Prior to a property transaction, the groundwater at an industrial refinery site in New Jersey was found to be contaminated with a variety of petroleum-based organic compounds. The highly built-up site included an on-site estuarine wetland and was located in a developed, industrialized area near ecologically important estuarine marshes. A preliminary ecological risk assessment was developed on the basis of available data on site contamination and ecological resources. The onsite wetland and its user fauna were identified as the sensitive receptors of concern and the primary contaminant pathways wee identified. The ecological significance of the contamination was assessed with regard to the onsite wetland and in the context of its position within the landscape and surrounding land uses. The wetland exhibited a combination of impact and vitality, i.e., there were clearly visible signs of contaminant impact as well as a relatively complex and abundant food web. Because of its position within the developed landscape, the onsite wetland appeared to function as a refugium for wildlife despite the level of disturbance. The feasibility of achieving regulatory compliance through natural remediation was also examined with respect to the findings of the risk assessment and the resultant conclusions are discussed

Ground-Water Flow, 2004-07, and Water Quality, 1992-2007, in McBaine Bottoms, Columbia, Missouri

Science.gov (United States)

Smith, Brenda Joyce; Richards, Joseph M.

2008-01-01

The U.S. Geological Survey, in cooperation with the city of Columbia, Missouri, and the Missouri Department of Conservation, collected ground-water quality data, surface-water quality data, and water-level data in McBaine Bottoms, southwest of Columbia. McBaine Bottoms, adjacent to the Missouri River, is the location of the municipal-supply well field for the city of Columbia, the city of Columbia wastewater-treatment wetlands, and the Missouri Department of Conservation Eagle Bluffs Conservation Area. This report describes the ground-water flow and water quality of McBaine Bottoms and provides information to better understand the interaction between treated effluent from the wetlands used on the Eagle Bluffs Conservation Area and the water in the alluvial aquifer that is pumped from the city of Columbia municipal-supply well field. Changes in major chemical constituent concentrations have been detected at several sampling sites between pre- and post-effluent application data. Analysis of post-effluent data indicates substantial changes in calcium, potassium, sodium, chloride, and sulfate concentrations in ground water. These changes became apparent shortly after the beginning of the operation of the wastewater-treatment wetland in 1994 and the formation of the Eagle Bluffs Conservation Area, which uses the treated effluent as a water source for the management of migratory water fowl. The changes have continued throughout the 15 years of sample collection. The concentrations of these major chemical constituents are on the mixing continuum between pre-effluent ground water as one end member and the treated wastewater effluent as the other end member. For monitoring wells that had changes in major chemical constituent concentrations, the relative percentage of treated effluent in the ground water, assuming chloride is conservative, ranged from 6 to 88 percent. Twenty-two monitoring wells throughout McBaine Bottoms have been affected by effluent based on chloride

A high-resolution global-scale groundwater model

Science.gov (United States)

de Graaf, I. E. M.; Sutanudjaja, E. H.; van Beek, L. P. H.; Bierkens, M. F. P.

2015-02-01

Groundwater is the world's largest accessible source of fresh water. It plays a vital role in satisfying basic needs for drinking water, agriculture and industrial activities. During times of drought groundwater sustains baseflow to rivers and wetlands, thereby supporting ecosystems. Most global-scale hydrological models (GHMs) do not include a groundwater flow component, mainly due to lack of geohydrological data at the global scale. For the simulation of lateral flow and groundwater head dynamics, a realistic physical representation of the groundwater system is needed, especially for GHMs that run at finer resolutions. In this study we present a global-scale groundwater model (run at 6' resolution) using MODFLOW to construct an equilibrium water table at its natural state as the result of long-term climatic forcing. The used aquifer schematization and properties are based on available global data sets of lithology and transmissivities combined with the estimated thickness of an upper, unconfined aquifer. This model is forced with outputs from the land-surface PCRaster Global Water Balance (PCR-GLOBWB) model, specifically net recharge and surface water levels. A sensitivity analysis, in which the model was run with various parameter settings, showed that variation in saturated conductivity has the largest impact on the groundwater levels simulated. Validation with observed groundwater heads showed that groundwater heads are reasonably well simulated for many regions of the world, especially for sediment basins (R2 = 0.95). The simulated regional-scale groundwater patterns and flow paths demonstrate the relevance of lateral groundwater flow in GHMs. Inter-basin groundwater flows can be a significant part of a basin's water budget and help to sustain river baseflows, especially during droughts. Also, water availability of larger aquifer systems can be positively affected by additional recharge from inter-basin groundwater flows.

Experimental and numerical modelling of surface water-groundwater flow and pollution interactions under tidal forcing

Science.gov (United States)

Spanoudaki, Katerina; Bockelmann-Evans, Bettina; Schaefer, Florian; Kampanis, Nikolaos; Nanou-Giannarou, Aikaterini; Stamou, Anastasios; Falconer, Roger

2015-04-01

Surface water and groundwater are integral components of the hydrologic continuum and the interaction between them affects both their quantity and quality. However, surface water and groundwater are often considered as two separate systems and are analysed independently. This separation is partly due to the different time scales, which apply in surface water and groundwater flows and partly due to the difficulties in measuring and modelling their interactions (Winter et al., 1998). Coastal areas in particular are a difficult hydrologic environment to represent with a mathematical model due to the large number of contributing hydrologic processes. Accurate prediction of interactions between coastal waters, groundwater and neighbouring wetlands, for example, requires the use of integrated surface water-groundwater models. In the past few decades a large number of mathematical models and field methods have been developed in order to quantify the interaction between groundwater and hydraulically connected surface water bodies. Field studies may provide the best data (Hughes, 1995) but are usually expensive and involve too many parameters. In addition, the interpretation of field measurements and linking with modelling tools often proves to be difficult. In contrast, experimental studies are less expensive and provide controlled data. However, experimental studies of surface water-groundwater interaction are less frequently encountered in the literature than filed studies (e.g. Ebrahimi et al., 2007; Kuan et al., 2012; Sparks et al., 2013). To this end, an experimental model has been constructed at the Hyder Hydraulics Laboratory at Cardiff University to enable measurements to be made of groundwater transport through a sand embankment between a tidal water body such as an estuary and a non-tidal water body such as a wetland. The transport behaviour of a conservative tracer was studied for a constant water level on the wetland side of the embankment, while running a

Quarterly sampling of the wetlands along the old F-Area effluent ditch, Revision 1

Energy Technology Data Exchange (ETDEWEB)

Dixon, K.L.; cummins, C.L.

1994-05-01

In May 1994, well point water and bucket samples were collected for tritium and volatile organic compounds in the wetlands along the old F-Area effluent ditch south of 643-E (old burial ground). The well point samples were collected from seven locations and the bucket samples from four locations. Results support that T and VOCs originating from 643-E are outcropping in the wetlands near this ditch. Based on differences in tritium contents at each location, it was determined that the sampling devices intercepted different groundwater flow paths; however, when VOCs were normalized, based on differences in T, resulting well point and bucket VOCs were comparable in most cases.

Using constructed wetlands to treat subsurface drainage from intensively grazed dairy pastures in New Zealand.

Science.gov (United States)

Tanner, C C; Nguyen, M Long; Sukias, J P S

2003-01-01

Performance data, during the start-up period, are presented for constructed wetlands treating subsurface drainage from dairy pastures in Waikato (rain-fed) and Northland (irrigated), North Island, New Zealand. The wetlands comprised an estimated 1 and 2% of the drained catchment areas, respectively. Nitrate concentrations were high in the drainage inflows at both sites (medians 10 g m(-3) at Waikato and 6.5 g m(-3) at Northland), but organic N was also an important form of N at Waikato (37% of TN). Comparison of wetland inflow and outflow nutrient concentrations showed overall nutrient reductions during passage through the wetlands for NO3-N (34 and 94% for medians, respectively), TN (56 and 33%, respectively), and DRP (80%, Northland only). Median NH4-N (both sites) and DRP (Waikato) concentrations showed apparent increases between the wetland inlets and outlets. However, a mass balance calculated for the 3 month preliminary monitoring periods showed substantial mass removal of DRP (80%) and all measured forms of N (NO3-N 78%, NH4-N 41%, Org-N 99.8% and TN 96%) in the Waikato wetland. Monitoring of these systems needs to be continued through a range of seasons and years to fully assess their long-term performance.

Wetlands and Sustainability

Directory of Open Access Journals (Sweden)

Richard Smardon

2014-11-01

Full Text Available This editorial provides an overview of the special issue “Wetlands and Sustainability”. In particular, the special issue contains a review of Paul Keddy’s book “Wetland Ecology” with specific reference to wetland sustainability. It also includes papers addressing wetland data acquisition via radar and remote sensing to better understand wetland system dynamics, hydrologic processes linked to wetland stress and restoration, coastal wetlands land use conflict/management, and wetland utilization for water quality treatment.

Pesticide concentrations in frog tissue and wetland habitats in alandscape dominated by agriculture

Science.gov (United States)

Smalling, Kelly L.; Reeves, Rebecca; Muths, Erin L.; Vandever, Mark W.; Battaglin, William A.; Hladik, Michelle; Pierce, Clay L.

2015-01-01

Habitat loss and exposure to pesticides are likely primary factors contributing to amphibian decline in agricultural landscapes. Conservation efforts have attempted to restore wetlands lost through landscape modifications to reduce contaminant loads in surface waters and providing quality habitat to wildlife. The benefits of this increased wetland area, perhaps especially for amphibians, may be negated if habitat quality is insufficient to support persistent populations. We examined the presence of pesticides and nutrients in water and sediment as indicators of habitat quality and assessed the bioaccumulation of pesticides in the tissue of two native amphibian species Pseudacris maculata (chorus frogs) and Lithobates pipiens (leopard frogs) at six wetlands (3 restored and 3 reference) in Iowa, USA. Restored wetlands are positioned on the landscape to receive subsurface tile drainage water while reference wetlands receive water from overland run-off and shallow groundwater sources. Concentrations of the pesticides frequently detected in water and sediment samples were not different between wetland types. The median concentration of atrazine in surface water was 0.2 μg/L. Reproductive abnormalities in leopard frogs have been observed in other studies at these concentrations. Nutrient concentrations were higher in the restored wetlands but lower than concentrations thought lethal to frogs. Complex mixtures of pesticides including up to 8 fungicides, some previously unreported in tissue, were detected with concentrations ranging from 0.08 to 1500 μg/kg wet weight. No significant differences in pesticide concentrations were observed between species, although concentrations tended to be higher in leopard frogs compared to chorus frogs, possibly because of differences in life histories. Our results provide information on habitat quality in restored wetlands that will assist state and federal agencies, landowners, and resource managers in identifying and

Water-carbon Links in a Tropical Forest: How Interbasin Groundwater Flow Affects Carbon Fluxes and Ecosystem Carbon Budgets

Energy Technology Data Exchange (ETDEWEB)

Genereux, David [North Carolina State Univ., Raleigh, NC (United States); Osburn, Christopher [North Carolina State Univ., Raleigh, NC (United States); Oberbauer, Steven [Florida Intl Univ., Miami, FL (United States); Oviedo Vargas, Diana [North Carolina State Univ., Raleigh, NC (United States); Dierick, Diego [Florida Intl Univ., Miami, FL (United States)

2017-03-27

This report covers the outcomes from a quantitative, interdisciplinary field investigation of how carbon fluxes and budgets in a lowland tropical rainforest are affected by the discharge of old regional groundwater into streams, springs, and wetlands in the forest. The work was carried out in a lowland rainforest of Costa Rica, at La Selva Biological Station. The research shows that discharge of regional groundwater high in dissolved carbon dioxide represents a significant input of carbon to the rainforest "from below", an input that is on average larger than the carbon input "from above" from the atmosphere. A stream receiving discharge of regional groundwater had greatly elevated emissions of carbon dioxide (but not methane) to the overlying air, and elevated downstream export of carbon from its watershed with stream flow. The emission of deep geological carbon dioxide from stream water elevates the carbon dioxide concentrations in air above the streams. Carbon-14 tracing revealed the presence of geological carbon in the leaves and stems of some riparian plants near streams that receive inputs of regional groundwater. Also, discharge of regional groundwater is responsible for input of dissolved organic matter with distinctive chemistry to rainforest streams and wetlands. The discharge of regional groundwater in lowland surface waters has a major impact on the carbon cycle in this and likely other tropical and non-tropical forests.

Ohio Uses Wetlands Program Development Grants to Protect Wetlands

Science.gov (United States)

The wetland water quality standards require the use of ORAM score to determine wetland quality. OEPA has also used these tools to evaluate wetland mitigation projects, develop performance standards for wetland mitigation banks and In Lieu Fee programs an.

Spatial distribution of mercury in southeastern Alaskan streams influenced by glaciers, wetlands, and salmon

International Nuclear Information System (INIS)

Nagorski, Sonia A.; Engstrom, Daniel R.; Hudson, John P.; Krabbenhoft, David P.; Hood, Eran; DeWild, John F.; Aiken, George R.

2014-01-01

Southeastern Alaska is a remote coastal-maritime ecosystem that is experiencing increased deposition of mercury (Hg) as well as rapid glacier loss. Here we present the results of the first reported survey of total and methyl Hg (MeHg) concentrations in regional streams and biota. Overall, streams draining large wetland areas had higher Hg concentrations in water, mayflies, and juvenile salmon than those from glacially-influenced or recently deglaciated watersheds. Filtered MeHg was positively correlated with wetland abundance. Aqueous Hg occurred predominantly in the particulate fraction of glacier streams but in the filtered fraction of wetland-rich streams. Colonization by anadromous salmon in both glacier and wetland-rich streams may be contributing additional marine-derived Hg. The spatial distribution of Hg in the range of streams presented here shows that watersheds are variably, yet fairly predictably, sensitive to atmospheric and marine inputs of Hg. -- Highlights: • We sampled 21 streams in southeastern Alaska for water, sediments, and biota. • Aqueous Hg showed significant relationships with wetlands and DOC. • Biota had higher mercury in wetland-rich streams than in glacier-fed streams. • Spawning salmon appear to contribute methylmercury to stream foodwebs. -- This original survey of mercury concentration and form in southeastern Alaskan streamwater and biota shows substantial spatial variation linked to landscape factors and salmon influence

Evaluation of constructed wetland treatment performance for winery wastewater.

Science.gov (United States)

Grismer, Mark E; Carr, Melanie A; Shepherd, Heather L

2003-01-01

Rapid expansion of wineries in rural California during the past three decades has created contamination problems related to winery wastewater treatment and disposal; however, little information is available about performance of on-site treatment systems. Here, the project objective was to determine full-scale, subsurface-flow constructed wetland retention times and treatment performance through assessment of water quality by daily sampling of total dissolved solids, pH, total suspended solids, chemical oxygen demand (COD), tannins, nitrate, ammonium, total Kjeldahl nitrogen, phosphate, sulfate, and sulfide across operating systems for winery wastewater treatment. Measurements were conducted during both the fall crush season of heavy loading and the spring following bottling and racking operations at the winery. Simple decay model coefficients for these constituents as well as COD and tannin removal efficiencies from winery wastewater in bench-scale reactors are also determined. The bench-scale study used upward-flow, inoculated attached-growth (pea-gravel substrate) reactors fed synthetic winery wastewater. Inlet and outlet tracer studies for determination of actual retention times were essential to analyses of treatment performance from an operational subsurface-flow constructed wetland that had been overloaded due to failure to install a pretreatment system for suspended solids removal. Less intensive sampling conducted at a smaller operational winery wastewater constructed wetland that had used pretreatment suspended solids removal and aeration indicated that the constructed wetlands were capable of complete organic load removal from the winery wastewater.

Hydrological and hydro-geological effects on wetlands and forest areas from the repository at Forsmark. Results from modelling with MIKE SHE; Hydrologiska och hydrogeologiska effekter paa vaatmarker och skogsomraaden av slutfoervarsanlaeggningen i Forsmark. Resultat fraan modellering med MIKE SHE

Energy Technology Data Exchange (ETDEWEB)

Maartensson, Erik; Gustafsson, Lars-Goeran; Gustafsson, Ann-Marie; Aneljung, Maria; Sabel, Ulrika (DHI Sverige AB, Goeteborg (Sweden))

2010-06-15

This report provides background material for investigations and associated impact assessments concerning water operations in terms of withdrawal of groundwater from the final repository for spent nuclear fuel at Forsmark. The report presents detailed modelling results in the form of supplementary sensitivity analyses and detailed hydrological and hydrogeological analyses of specific nature objects in Forsmark. The sensitivity analyses aim to investigate the sensitivity of the modelling results to i) the meteorological conditions, ii) impervious surfaces and iii) the model description of the present SFR (final repository for short-lived radioactive waste). A number of simulation cases aim to study cumulative effects of groundwater withdrawal from an extended SFR. The simulations are evaluated with respect to the groundwater table drawdown and head changes in the bedrock. The report analyses the hydrogeological and hydrological conditions for a number of selected wetland objects and forest objects. The selection of objects aims to cover different types of valuable nature objects at different geographical locations in relation to the influence area of the groundwater table drawdown. The analysis comprises groundwater levels at all nature objects, whereas wetlands with particularly high nature values have been studied in detail with respect to surface water levels, the need for water supply and object-specific water balances. These studies have been performed for different meteorological conditions in the form of a type (2006) and a statistically normal, dry and wet year, respectively, with a return period of 100 years for the dry- and wet years. All simulations for disturbed conditions with a fully open repository are done with a hydraulic conductivity of K{sub inj} = 10-7 or 10-8 m/s in the grouted zone. The results show that time-dependent precipitation and snow melt have large influence on the temporal variations of the depth to the groundwater table for

Groundwater-fed irrigation impacts spatially distributed temporal scaling behavior of the natural system: a spatio-temporal framework for understanding water management impacts

International Nuclear Information System (INIS)

Condon, Laura E; Maxwell, Reed M

2014-01-01

Regional scale water management analysis increasingly relies on integrated modeling tools. Much recent work has focused on groundwater–surface water interactions and feedbacks. However, to our knowledge, no study has explicitly considered impacts of management operations on the temporal dynamics of the natural system. Here, we simulate twenty years of hourly moisture dependent, groundwater-fed irrigation using a three-dimensional, fully integrated, hydrologic model (ParFlow-CLM). Results highlight interconnections between irrigation demand, groundwater oscillation frequency and latent heat flux variability not previously demonstrated. Additionally, the three-dimensional model used allows for novel consideration of spatial patterns in temporal dynamics. Latent heat flux and water table depth both display spatial organization in temporal scaling, an important finding given the spatial homogeneity and weak scaling observed in atmospheric forcings. Pumping and irrigation amplify high frequency (sub-annual) variability while attenuating low frequency (inter-annual) variability. Irrigation also intensifies scaling within irrigated areas, essentially increasing temporal memory in both the surface and the subsurface. These findings demonstrate management impacts that extend beyond traditional water balance considerations to the fundamental behavior of the system itself. This is an important step to better understanding groundwater’s role as a buffer for natural variability and the impact that water management has on this capacity. (paper)

Dissipation of hydrological tracers and the herbicide S-metolachlor in batch and continuous-flow wetlands.

Science.gov (United States)

Maillard, Elodie; Lange, Jens; Schreiber, Steffi; Dollinger, Jeanne; Herbstritt, Barbara; Millet, Maurice; Imfeld, Gwenaël

2016-02-01

Pesticide dissipation in wetland systems with regard to hydrological conditions and operational modes is poorly known. Here, we investigated in artificial wetlands the impact of batch versus continuous-flow modes on the dissipation of the chiral herbicide S-metolachlor (S-MET) and hydrological tracers (bromide, uranine and sulforhodamine B). The wetlands received water contaminated with the commercial formulation Mercantor Gold(®) (960 g L(-1) of S-MET, 87% of the S-enantiomer). The tracer mass budget revealed that plant uptake, sorption, photo- and presumably biodegradation were prominent under batch mode (i.e. characterized by alternating oxic-anoxic conditions), in agreement with large dissipation of S-MET (90%) under batch mode. Degradation was the main dissipation pathway of S-MET in the wetlands. The degradate metolachlor oxanilic acid (MOXA) mainly formed under batch mode, whereas metolachlor ethanesulfonic acid (MESA) prevailed under continuous-flow mode, suggesting distinct degradation pathways in each wetland. R-enantiomer was preferentially degraded under batch mode, which indicated enantioselective biodegradation. The release of MESA and MOXA by the wetlands as well as the potential persistence of S-MET compared to R-MET under both oxic and anoxic conditions may be relevant for groundwater and ecotoxicological risk assessment. This study shows the effect of batch versus continuous modes on pollutant dissipation in wetlands, and that alternate biogeochemical conditions under batch mode enhance S-MET biodegradation. Copyright © 2015 Elsevier Ltd. All rights reserved.

Pesticide concentrations in frog tissue and wetland habitats in a landscape dominated by agriculture.

Science.gov (United States)

Smalling, Kelly L; Reeves, Rebecca; Muths, Erin; Vandever, Mark; Battaglin, William A; Hladik, Michelle L; Pierce, Clay L

2015-01-01

Habitat loss and exposure to pesticides are likely primary factors contributing to amphibian decline in agricultural landscapes. Conservation efforts have attempted to restore wetlands lost through landscape modifications to reduce contaminant loads in surface waters and providing quality habitat to wildlife. The benefits of this increased wetland area, perhaps especially for amphibians, may be negated if habitat quality is insufficient to support persistent populations. We examined the presence of pesticides and nutrients in water and sediment as indicators of habitat quality and assessed the bioaccumulation of pesticides in the tissue of two native amphibian species Pseudacris maculata (chorus frogs) and Lithobates pipiens (leopard frogs) at six wetlands (3 restored and 3 reference) in Iowa, USA. Restored wetlands are positioned on the landscape to receive subsurface tile drainage water while reference wetlands receive water from overland run-off and shallow groundwater sources. Concentrations of the pesticides frequently detected in water and sediment samples were not different between wetland types. The median concentration of atrazine in surface water was 0.2 μg/L. Reproductive abnormalities in leopard frogs have been observed in other studies at these concentrations. Nutrient concentrations were higher in the restored wetlands but lower than concentrations thought lethal to frogs. Complex mixtures of pesticides including up to 8 fungicides, some previously unreported in tissue, were detected with concentrations ranging from 0.08 to 1,500 μg/kg wet weight. No significant differences in pesticide concentrations were observed between species, although concentrations tended to be higher in leopard frogs compared to chorus frogs, possibly because of differences in life histories. Our results provide information on habitat quality in restored wetlands that will assist state and federal agencies, landowners, and resource managers in identifying and implementing

Patterned Ground in Wetlands of the Maya Lowlands: Anthropogenic and Natural Causes

Science.gov (United States)

Beach, T.; Beach, S. L.

2004-12-01

We use geological and archaeological evidence to understand the formation of patterned ground in perennial and seasonal wetlands in the karst depressions of Belize and Guatemala. Some scholars have argued that these features are the remnants of ancient Maya wetland fields, chinampas, on which intensive cultivation produced food that could begin to nourish the extremely high population of the Late Classic (A.D. 550-850). Others have argued that these were natural features or that they represent landscape manipulation for rising sea level in the Preclassic (1000 B.C. -A.D. 250). We present the evidence for ancient intensive agriculture and natural landscape formation with multiple proxies: excavated field and canal features, artifacts, pollen, soil stratigraphy, and water chemistry. Evidence thus far suggests that many regional depressions have Preclassic (1200 BC to AD 200) or earlier paleosols, buried from 1-2 m by eroded soils induced by Maya land use practices. These paleosols were buried by eroded sediments from uplands and by precipitation of gypsum from rising groundwater. The sedimentation occurred largely between the Preclassic and Late Classic, when ancient Maya farmers built canals in pre-existing low spots to reclaim these wetlands. Thus, stable natural processes, environmental change, and human manipulation have acted together to form patterned wetland ground over the later Holocene.

Hydroregime prediction models for ephemeral groundwater-driven sinkhole wetlands: a planning tool for climate change and amphibian conservation

Science.gov (United States)

C. H. Greenberg; S. Goodrick; J. D. Austin; B. R. Parresol

2015-01-01

Hydroregimes of ephemeral wetlands affect reproductive success of many amphibian species and are sensitive to altered weather patterns associated with climate change.We used 17 years of weekly temperature, precipitation, and waterdepth measurements for eight small, ephemeral, groundwaterdriven sinkhole wetlands in Florida sandhills to develop a hydroregime predictive...

Analysing the origin of rain- and subsurface water in seasonal wetlands of north-central Namibia

Science.gov (United States)

Hiyama, Tetsuya; Kanamori, Hironari; Kambatuku, Jack R.; Kotani, Ayumi; Asai, Kazuyoshi; Mizuochi, Hiroki; Fujioka, Yuichiro; Iijima, Morio

2017-03-01

We investigated the origins of rain- and subsurface waters of north-central Namibia’s seasonal wetlands, which are critical to the region’s water and food security. The region includes the southern part of the Cuvelai system seasonal wetlands (CSSWs) of the Cuvelai Basin, a transboundary river basin covering southern Angola and northern Namibia. We analysed stable water isotopes (SWIs) of hydrogen (HDO) and oxygen (H2 18O) in rainwater, surface water and shallow groundwater. Rainwater samples were collected during every rainfall event of the rainy season from October 2013 to April 2014. The isotopic ratios of HDO (δD) and oxygen H2 18O (δ 18O) were analysed in each rainwater sample and then used to derive the annual mean value of (δD, δ 18O) in precipitation weighted by each rainfall volume. Using delta diagrams (plotting δD vs. δ 18O), we showed that the annual mean value was a good indicator for determining the origins of subsurface waters in the CSSWs. To confirm the origins of rainwater and to explain the variations in isotopic ratios, we conducted atmospheric water budget analysis using Tropical Rainfall Measuring Mission (TRMM) multi-satellite precipitation analysis (TMPA) data and ERA-Interim atmospheric reanalysis data. The results showed that around three-fourths of rainwater was derived from recycled water at local-regional scales. Satellite-observed outgoing longwave radiation (OLR) and complementary satellite data from MODerate-resolution Imaging Spectroradiometer (MODIS) and Advanced Microwave Scanning Radiometer (AMSR) series implied that the isotopic ratios in rainwater were affected by evaporation of raindrops falling from convective clouds. Consequently, integrated SWI analysis of rain-, surface and subsurface waters, together with the atmospheric water budget analysis, revealed that shallow groundwater of small wetlands in this region was very likely to be recharged from surface waters originating from local rainfall, which was

Modeling natural wetlands: A new global framework built on wetland observations

Science.gov (United States)

Matthews, E.; Romanski, J.; Olefeldt, D.

2015-12-01

Natural wetlands are the world's largest methane (CH4) source, and their distribution and CH4 fluxes are sensitive to interannual and longer-term climate variations. Wetland distributions used in wetland-CH4 models diverge widely, and these geographic differences contribute substantially to large variations in magnitude, seasonality and distribution of modeled methane fluxes. Modeling wetland type and distribution—closely tied to simulating CH4 emissions—is a high priority, particularly for studies of wetlands and CH4 dynamics under past and future climates. Methane-wetland models either prescribe or simulate methane-producing areas (aka wetlands) and both approaches result in predictable over- and under-estimates. 1) Monthly satellite-derived inundation data include flooded areas that are not wetlands (e.g., lakes, reservoirs, and rivers), and do not identify non-flooded wetlands. 2) Models simulating methane-producing areas overwhelmingly rely on modeled soil moisture, systematically over-estimating total global area, with regional over- and under-estimates, while schemes to model soil-moisture typically cannot account for positive water tables (i.e., flooding). Interestingly, while these distinct hydrological approaches to identify wetlands are complementary, merging them does not provide critical data needed to model wetlands for methane studies. We present a new integrated framework for modeling wetlands, and ultimately their methane emissions, that exploits the extensive body of data and information on wetlands. The foundation of the approach is an existing global gridded data set comprising all and only wetlands, including vegetation information. This data set is augmented with data inter alia on climate, inundation dynamics, soil type and soil carbon, permafrost, active-layer depth, growth form, and species composition. We investigate this enhanced wetland data set to identify which variables best explain occurrence and characteristics of observed

Relations between vegetation and water level in groundwater dependent terrestrial ecosystems (GWDTEs)

DEFF Research Database (Denmark)

Munch Johansen, Ole; Andersen, Dagmar Kappel; Ejrnæs, Rasmus

2018-01-01

, management and conservation of fens are constrained by limited knowledge on the relations between vegetation and measurable hydrological conditions. This study investigates the relations between vegetation and water level dynamics in groundwater dependent wetlands in Denmark. A total of 35 wetland sites...... across Denmark were included in the study. The sites represent a continuum of wetlands with respect to vegetation and hydrological conditions. Water level was measured continuously using pressure transducers at each site. Metrics expressing different hydrological characteristics, such as mean water level...... and low and high water level periods, were calculated based on the water level time series. A complete plant species list was recorded in plots covering 78.5 m2 at each site. Community metrics such as total number of species and the number of bryophytes were generated from the species lists and Ellenberg...

Framework to evaluate the worth of hydraulic conductivity data for optimal groundwater resources management in ecologically sensitive areas

Science.gov (United States)

Feyen, Luc; Gorelick, Steven M.

2005-03-01

We propose a framework that combines simulation optimization with Bayesian decision analysis to evaluate the worth of hydraulic conductivity data for optimal groundwater resources management in ecologically sensitive areas. A stochastic simulation optimization management model is employed to plan regionally distributed groundwater pumping while preserving the hydroecological balance in wetland areas. Because predictions made by an aquifer model are uncertain, groundwater supply systems operate below maximum yield. Collecting data from the groundwater system can potentially reduce predictive uncertainty and increase safe water production. The price paid for improvement in water management is the cost of collecting the additional data. Efficient data collection using Bayesian decision analysis proceeds in three stages: (1) The prior analysis determines the optimal pumping scheme and profit from water sales on the basis of known information. (2) The preposterior analysis estimates the optimal measurement locations and evaluates whether each sequential measurement will be cost-effective before it is taken. (3) The posterior analysis then revises the prior optimal pumping scheme and consequent profit, given the new information. Stochastic simulation optimization employing a multiple-realization approach is used to determine the optimal pumping scheme in each of the three stages. The cost of new data must not exceed the expected increase in benefit obtained in optimal groundwater exploitation. An example based on groundwater management practices in Florida aimed at wetland protection showed that the cost of data collection more than paid for itself by enabling a safe and reliable increase in production.

Tracing coastal and estuarine groundwater discharge sources in a complex faulted and fractured karst aquifer system

Science.gov (United States)

Lagomasino, D.; Price, R. M.

2013-05-01

Groundwater discharge can be an important input of water, nutrients and other constituents to coastal wetlands and adjacent marine areas, particularly in karst regions with little to no surface water flow. A combination of natural processes (e.g., sea-level rise and climate change) and anthropogenic pressures (e.g., urban growth and development) can alter the subterranean water flow to the coastline. For water management practices and environmental preservation to be better suited for the natural and human environment, a better understanding is needed of the hydrogeologic connectivity between the areas of fresh groundwater recharge and the coastal zone. The Yucatan peninsula has a unique tectonic and geologic history consisting of a Cretaceous impact crater, Miocene and Eocene tectonic plate movements, and multiple sea-level stands. These events have shaped many complex geologic formations and structures. The Sian Káan Biosphere Reserve (SKBR), a UNESCO World Heritage Site located along the Atlantic Ocean, overlaps two distinct hydrogeologic regions: the evaporate region to the south and south west, and the Holbox Fracture Zone to the north. These two regions create a complex network of layered, perched and fractured aquifers and an extensive groundwater cave network. The two regions are distinguished by bedrock mineralogical differences that can be used to trace shallow subsurface water from interior portions of the peninsula to the Bahia de la Ascension in the SKBR. The objective of this research was to use naturally occurring geochemical tracers (eg., Cl-, SO42-, HCO3-, K+, Mg2+, Na+, Ca2+ and stable isotopes of oxygen and hydrogen) to decipher the sources of groundwater flow through the coastal wetlands of the SKBR and into the Bahia de la Ascension. Surface water and groundwater samples were collected during two field campaigns in 2010 and 2012 within the coastal and estuarine waters of the SKBR. Additional water samples were collected at select cenotes along

Retention of heavy metals and poly-aromatic hydrocarbons from road water in a constructed wetland and the effect of de-icing

KAUST Repository

Tromp, Karin; Lima, Ana T.; Barendregt, Arjan; Verhoeven, Jos T.A.

2012-01-01

basin, a vertical-flow reed bed and a final groundwater infiltration bed. Water samples were taken of road water, detention basin influent and wetland effluent. By using automated sampling, we were able to obtain reliable concentration averages per 4

Simulation of groundwater flow and interaction of groundwater and surface water on the Lac du Flambeau Reservation, Wisconsin

Science.gov (United States)

Juckem, Paul F.; Fienen, Michael N.; Hunt, Randall J.

2014-01-01

resulting simulated lake stage and water budgets to stages and water budgets from the calibrated model. Simulated lake water budgets and water level changes illustrate the importance of understanding the position of a lake within the hydrologic system (headwater or downstream), the type of lake (surface-water drainage or seepage lake), and the role of groundwater in dampening the effects of large-scale changes in weather patterns on lake levels. Areas contributing recharge to drinking-water supply wells on the Reservation were delineated using forward particle tracking from the water table to the well. Monte Carlo uncertainty analyses were used to produce maps showing the probability of groundwater capture for areas around each well nest. At the Main Pumphouse site near the Village of Lac du Flambeau, most of the area contributing recharge to the wells occurs downgradient from a large wetland between the wells and the wastewater infiltration lagoons. Nonetheless, a small potential for the wells to capture infiltrated wastewater is apparent when considering uncertainty in the model parameter values. At the West Pumphouse wells south of Flambeau Lake, most of the area contributing recharge is between the wells and Tippecanoe Lake. The extent of infiltrated wastewater from two infiltration lagoons was tracked using the groundwater flow model and Monte Carlo uncertainty analyses. Wastewater infiltrated from the lagoons flows predominantly south toward Moss Lake as it integrates with the regional groundwater flow system. The wastewater-plume-extent simulations support the area-contributing-recharge simulations, indicating that there is a possibility, albeit at low probability, that some wastewater could be captured by water-supply wells. Comparison of simulated water-table contours indicate that the lagoons may mound the water table approximately 4 ft, with diminishing levels of mounding outward from the lagoons. Four scenarios, representing potential alternatives for wastewater

Biodiversity impacts from salinity increase in a coastal wetland.

Science.gov (United States)

Amores, Maria José; Verones, Francesca; Raptis, Catherine; Juraske, Ronnie; Pfister, Stephan; Stoessel, Franziska; Antón, Assumpció; Castells, Francesc; Hellweg, Stefanie

2013-06-18

A Life Cycle Impact Assessment method was developed to evaluate the environmental impact associated with salinity on biodiversity in a Spanish coastal wetland. The developed characterization factor consists of a fate and an effect factor and equals 3.16 × 10(-1) ± 1.84 × 10(-1) PAF · m(3) · yr · m(-3) (PAF: Potentially Affected Fraction of species) indicating a "potential loss of 0.32 m(3) ecosystem" for a water consumption rate of 1 m(3) · yr(-1). As a result of groundwater consumption with a rate of 1 m(3) · yr(-1), the PAF in the lost cubic meter of ecosystem equals 0.05, which has been proposed as the maximum tolerable effect to keep the ecosystem intact. The fate factor was calculated from seasonal water balances of the wetland Albufera de Adra. The effect factor was obtained from the fitted curve of the potentially affected fraction of native wetland species due to salinity and can be applied to other wetlands with similar species composition. In order to test the applicability of the characterization factor, an assessment of water consumption of greenhouse crops in the area was conducted as a case study. Results converted into ecosystem quality damage using the ReCiPe method were compared to other categories. While tomatoes are responsible for up to 30% of the impact of increased salinity due to water consumption on ecosystem quality in the studied area, melons have the largest impact per tonne produced.

77 FR 63326 - Huron Wetland Management District, Madison Wetland Management District, and Sand Lake Wetland...

Science.gov (United States)

2012-10-16

..., consistent with sound principles of fish and wildlife management, conservation, legal mandates, and our... FXRS1265066CCP0] Huron Wetland Management District, Madison Wetland Management District, and Sand Lake Wetland Management District, SD; Final Comprehensive Conservation Plan and Finding of No Significant Impact for...

Wetland Ecohydrology: stochastic description of water level fluctuations across the soil surface

Science.gov (United States)

Tamea, S.; Muneepeerakul, R.; Laio, F.; Ridolfi, L.; Rodriguez-Iturbe, I.

2009-12-01

Wetlands provide a suite of social and ecological critical functions such as being habitats of disease-carrying vectors, providing buffer zones against hurricanes, controlling sediment transport, filtering nutrients and contaminants, and a repository of great biological diversity. More recently, wetlands have also been recognized as crucial for carbon storage in the context of global climate change. Despite such importance, quantitative approaches to many aspects of wetlands are far from adequate. Therefore, improving our quantitative understanding of wetlands is necessary to our ability to maintain, manage, and restore these invaluable environments. In wetlands, hydrologic factors and ecosystem processes interplay and generate unique characteristics and a delicate balance between biotic and abiotic elements. The main hydrologic driver of wetland ecosystems is the position of the water level that, being above or below ground, determines the submergence or exposure of soil. When the water level is above the soil surface, soil saturation and lack of oxygen causes hypoxia, anaerobic functioning of microorganisms and anoxic stress in plants, that might lead to the death of non-adapted organisms. When the water level lies below the soil surface, the ecosystem becomes groundwater-dependent, and pedological and physiological aspects play their role in the soil water balance. We propose here a quantitative description of wetland ecohydrology, through a stochastic process-based water balance, driven by a marked compound Poisson noise representing rainfall events. The model includes processes such as rainfall infiltration, evapotranspiration, capillary rise, and the contribution of external water bodies, which are quantified in a simple yet realistic way. The semi-analytical steady-state probability distributions of water level spanning across the soil surface are validated with data from the Everglades (Florida, USA). The model and its results allow for a quantitative

Water Resources and Groundwater in a Glaciated Andean Watershed (Cordillera Blanca, Peru)

Science.gov (United States)

McKenzie, J. M.; Gordon, R.; Baraer, M.; Lautz, L.; Mark, B. G.; Wigmore, O.; Chavez, D.; Aubry-Wake, C.

2014-12-01

It is estimated that almost 400 million people live in watersheds where glaciers provide at least 10% of the runoff, yet many questions remain regarding the impact of climate change and glacier recession on water resources derived from these high mountain watersheds. We present research from the Cordillera Blanca, Peru, an area with the highest density of glaciers in the tropics. While glacier meltwater buffers stream discharge throughout the range, groundwater is a major component of dry season runoff, contributing up to 50-70% of outflow in some tributaries. In order to predict future changes to water resources it is critical to understand how groundwater can offset future hydrologic stress by maintaining stream baseflow, including recharge mechanisms, subsurface pathways, storage, and net fluxes to rivers. We present a synthesis of results based on hydrologic modeling, drilling/piezometers, geophysics, and artificial and natural hydrologic tracers. Our findings show that 'pampas', low-relief mountain valleys, are critical for baseflow generation by storing groundwater on interannual timescales. Pampas have a total area of ~65 km2 and are comprised of unconsolidated glacial, talus, lacustrine and wetland (bofedales) deposits. The valleys commonly have buried talus aquifers that are overlain by low permeability, glaciolacustrine deposits. Glaciofluvial outwash deposits and small wetlands also act as unconfined aquifers. These groundwater systems appear to be primarily recharged by wet season precipitation, and at higher elevations also by glacial meltwater. Additionally a ubiquitous feature in the valleys are springs, often located at the base of talus deposits, which generate a large hydrologic flux within the hydrologic systems. While glaciers are the most visible and vulnerable component of the Andean waterscape, we argue that it is crucial to understand the complete mountain hydrologic cycle, including groundwater, in order to understand the ongoing

Multiyear nutrient removal performance of three constructed wetlands intercepting tile drain flows from grazed pastures.

Science.gov (United States)

Tanner, Chris C; Sukias, James P S

2011-01-01

Subsurface tile drain flows can be a major s ource of nurient loss from agricultural landscapes. This study quantifies flows and nitrogen and phosphorus yields from tile drains at three intensively grazed dairy pasture sites over 3- to 5-yr periods and evaluates the capacity of constructed wetlands occupying 0.66 to 1.6% of the drained catchments too reduce nutrient loads. Continuous flow records are combined with automated flow-proportional sampling of nutrient concentrations to calculate tile drain nutrient yields and wetland mass removal rates. Annual drainage water yields rangedfrom 193 to 564 mm (16-51% of rainfall) at two rain-fed sites and from 827 to 853 mm (43-51% of rainfall + irrigation) at an irrigated site. Annually, the tile drains exported 14 to 109 kg ha(-1) of total N (TN), of which 58 to 90% was nitrate-N. Constructed wetlands intercepting these flows removed 30 to 369 gTN m(-2) (7-63%) of influent loadings annually. Seasonal percentage nitrate-N and TN removal were negatively associated with wetland N mass loadings. Wetland P removal was poor in all wetlands, with 12 to 115% more total P exported annually overall than received. Annually, the tile drains exported 0.12 to 1.38 kg ha of total P, of which 15 to 93% was dissolved reactive P. Additional measures are required to reduce these losses or provide supplementary P removal. Wetland N removal performance could be improved by modifying drainage systems to release flows more gradually and improving irrigation practices to reduce drainage losses.

East African wetland-catchment data base for sustainable wetland management

Science.gov (United States)

Leemhuis, Constanze; Amler, Esther; Diekkrüger, Bernd; Gabiri, Geofrey; Näschen, Kristian

2016-10-01

Wetlands cover an area of approx. 18 Mio ha in the East African countries of Kenya, Rwanda, Uganda and Tanzania, with still a relative small share being used for food production. Current upland agricultural use intensification in these countries due to demographic growth, climate change and globalization effects are leading to an over-exploitation of the resource base, followed by an intensification of agricultural wetland use. We aim on translating, transferring and upscaling knowledge on experimental test-site wetland properties, small-scale hydrological processes, and water related ecosystem services under different types of management from local to national scale. This information gained at the experimental wetland/catchment scale will be embedded as reference data within an East African wetland-catchment data base including catchment physical properties and a regional wetland inventory serving as a base for policy advice and the development of sustainable wetland management strategies.

East African wetland-catchment data base for sustainable wetland management

Directory of Open Access Journals (Sweden)

C. Leemhuis

2016-10-01

Full Text Available Wetlands cover an area of approx. 18 Mio ha in the East African countries of Kenya, Rwanda, Uganda and Tanzania, with still a relative small share being used for food production. Current upland agricultural use intensification in these countries due to demographic growth, climate change and globalization effects are leading to an over-exploitation of the resource base, followed by an intensification of agricultural wetland use. We aim on translating, transferring and upscaling knowledge on experimental test-site wetland properties, small-scale hydrological processes, and water related ecosystem services under different types of management from local to national scale. This information gained at the experimental wetland/catchment scale will be embedded as reference data within an East African wetland-catchment data base including catchment physical properties and a regional wetland inventory serving as a base for policy advice and the development of sustainable wetland management strategies.

Climate impacts on the hydrology of prairie wetlands

International Nuclear Information System (INIS)

Woo, Mingko; Rowsell, R.D.

1991-01-01

A study was carried out in the St. Denis National Wildlife Area, 45 km east of Saskatoon, to observe the hydrological processes and the temporal and spatial variability of slough responses to climate. One slough was instrumented for detailed study, showing that the high water level in spring was supported by snowmelt. In summer, rainfall was the major source of water supply, but was exceeded by losses to evaporation and groundwater recharge, leading to a decline of the water table and complete drying by June 13th. The duration that water remains in sloughs varies temporally and spatially. Ephemeral sloughs, deriving water mainly from snowmelt, tend to occupy higher ground, temporary sloughs rely on precipitation and surface runoff, and may receive groundwater discharge during wetter years. Permanent sloughs often occupy lower areas, receiving water from precipitation, lateral runoff, and groundwater discharge which buffers them from year to year fluctuations in precipitation. Tree ring analyses showed that meltwater is the major factor influencing tree growth, correlating the spatial variability of slough inundation to the temporal variability of winter snowfall. A study of slough hydrology is important to the understanding of the responses of Prairie wetlands to climatic variability and change. 17 refs., 2 figs

Monitoring of the water levels in the wetlands of Fourmile Branch near the F and H Areas of SRS: September 1997 to December 1998

International Nuclear Information System (INIS)

Halverson, N.V.

2000-01-01

A network of twenty-three piezometers was used to measure hydraulic head in the water-table aquifer along the groundwater outcrop (i.e. seepline) at the F- and H-Area seeplines. The piezometers were installed to assess potential impacts of the F- and H-Area Groundwater Remediation Waste Treatment Units on the riparian wetland system located between the former F- and H-Area seepage basins and Fourmile Branch

Evaluation of Subsurface Flow and Free-water Surface Wetlands Treating NPR-3 Produced Water - Year No. 1

International Nuclear Information System (INIS)

Myers, J. E.; Jackson, L. M.

2001-01-01

This paper is a summary of some of the activities conducted during the first year of a three-year cooperative research and development agreement (CRADA) between the Department of Energy (DOE) Rocky Mountain Oilfield Testing Center (RMOTC) and Texaco relating to the treatment of produced water by constructed wetlands. The first year of the CRADA is for design, construction and acclimation of the wetland pilot units. The second and third years of the CRADA are for tracking performance of pilot wetlands as the plant and microbial communities mature. A treatment wetland is a proven technology for the secondary and tertiary treatment of produced water, storm water and other wastewaters. Treatment wetlands are typically classified as either free-water surface (FWS) or subsurface flow (SSF). Both FWS and SSF wetlands work well when properly designed and operated. This paper presents a collection of kinetic data gathered from pilot units fed a slipstream of Wyoming (NPR-3) produced water. The pilot units are set up outdoors to test climatic influences on treatment. Monitoring parameters include evapotranspiration, plant growth, temperature, and NPDES discharge limits. The pilot wetlands (FWS and SSF) consist of a series of 100-gal plastic tubs filled with local soils, gravel, sharp sand and native wetland plants (cattail (Typha spp.), bulrush (Scirpus spp.), dwarf spikerush (Eleocharis)). Feed pumps control hydraulic retention time (HRT) and simple water control structures control the depth of water. The treated water is returned to the existing produced water treatment system. All NPDES discharge limits are met. Observations are included on training RMOTC summer students to do environmental work

Regional Assessment of Groundwater Recharge in the Lower Mekong Basin

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Guillaume Lacombe

2017-12-01

Full Text Available Groundwater recharge remains almost totally unknown across the Mekong River Basin, hindering the evaluation of groundwater potential for irrigation. A regional regression model was developed to map groundwater recharge across the Lower Mekong Basin where agricultural water demand is increasing, especially during the dry season. The model was calibrated with baseflow computed with the local-minimum flow separation method applied to streamflow recorded in 65 unregulated sub-catchments since 1951. Our results, in agreement with previous local studies, indicate that spatial variations in groundwater recharge are predominantly controlled by the climate (rainfall and evapotranspiration while aquifer characteristics seem to play a secondary role at this regional scale. While this analysis suggests large scope for expanding agricultural groundwater use, the map derived from this study provides a simple way to assess the limits of groundwater-fed irrigation development. Further data measurements to capture local variations in hydrogeology will be required to refine the evaluation of recharge rates to support practical implementations.

Peat wetland as a natural filter of effluents from adjacent industrial areas

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József DEZSO

2015-12-01

Full Text Available The main objective of the project is the study of a peat wetland functioning as recipient of effluents from former and present-day industrial activities. The investigation was focused on heavy metal contaminations and their probable mobilization or fixation. The studied peatbog is a typical Eastern European wetland, located in Hungary on the border between medium mountains (Bakony Mountains and a Neogene basin (the Sárrét, an area under nature conservation. Watercourses and prevailing air currents can transport contaminants from industrial areas to the wetland. At first the basic parameters of surface waters and subsurface conditions (soils, groundwater were investigated. These parameters (EC, Cl are possible indicators of contamination. Subsequently, the amounts of heavy metals (Cd, Pb extracted by solution in two steps (HCl, CaCl2 were measured using atomic absorption spectroscopy (AAS. The extracted values indicate what amounts of which elements could be mobilized by human impact and/or production of humic acids, which occasionally emerges during the remediation works. The total heavy metal concentrations in the samples were investigated by X-ray fluorescence method. Based on the investigation, the peatbog is claimed to function as a natural filter.

Influences of channelization on discharge of suspended sediment and wetland vegetation in Kushiro Marsh, northern Japan

Science.gov (United States)

Nakamura, Futoshi; Sudo, Tadashi; Kameyama, Satoshi; Jitsu, Mieko

1997-03-01

The effects of wetlands on hydrology, water quality, and wildlife habitat are internationally recognized. Protecting the remaining wetlands is one of the most important environmental issues in many countries. However wetlands in Japan have been gradually shrinking due to agricultural development and urbanization, which generally lowers the groundwater level and introduces suspended sediment and sediment-associated nutrients into wetlands. We examined the influences of channelization on discharge of suspended sediment and wetland vegetation in Hokkaido, northern Japan. The impact of river channelization was confirmed not only by the sediment budgets but also by river aggradation or degradation after the channelization and by the resultant vegetational changes. The budgets of suspended sediment demonstrated that wash load was the predominant component accounting for 95% of the total suspended load delivered into the wetland. This suspended sediment was primarily transported into the wetland by flooding associated with heavy rainfall. Twenty-three percent of the wash load and 63% of the suspended bed material load were deposited in the channelized reach, which produced aggradation of about 2 m at the end of the reach. A shorting of the length of the channel, due to channelization of a meandering river, steepened the slope and enhanced the stream power to transport sediment. This steepening shifted the depositional zones of fine sediment 5 km downstream and aggraded the riverbed. Development of the watershed may increase not only the water discharge but also the amount of suspended sediments. The aggradation reduced the carrying capacity of the channel and caused sediment ladened water to flood over the wetlands. The fine sediment accumulated on the wetlands gradually altered the edaphic conditions and wetland vegetation. A low percentage (10 to 15%) of organic contents of wetlands' soil is more evidence indicating that the present condition is far different from

Coastal Forests and Groundwater: Using Case Studies to Understand the Effects of Drivers and Stressors for Resource Management

Directory of Open Access Journals (Sweden)

Timothy J. Callahan

2017-03-01

Full Text Available Forests are receiving more attention for the ecosystem goods and services they provide and the potential change agents that may affect forest health and productivity. Highlighting case examples from coastal forests in South Carolina, USA, we describe groundwater processes with respect to stressors and potential responses of a wetland-rich forested landscape, the roles that this area has served, and the need for water resource data to inform forest management decisions. Forested lands in the southeastern U.S. coastal plain provide a rich set of goods and services for the region, and in one case, the Francis Marion National Forest acts as a buffer to urbanization from the surrounding Charleston metropolitan area. Information from two decades of studies in the forested watersheds there may inform scientists and managers in other coastal forested systems. The common hydrological theme in this region, which has a higher average annual rainfall (1370 mm than the annual potential evapotranspiration (PET = 1135 mm, is a shallow (<3 m water table condition that supports a large range of natural wetlands and also creates management challenges across the region. Modest changes in the position of the water table can lead to either groundwater flooding and concomitant management challenges for forest services, or ecosystem stresses related to dry conditions in wetlands during times of below-normal precipitation or due to groundwater withdrawal. Development pressures have also stressed forest resources through the extraction of materials such as timber and sand mining, and the conversion to housing construction materials. These areas are also targeted for land development, to meet housing demands. In this paper, we discuss the role of groundwater in coastal forests and highlight opportunities for collaborative studies to better inform forest resource management.

Using Tradtional Ecological Knowledge to Protect Wetlands: the Swinomish Tribe's Wetland Cultural Assessment Project

Science.gov (United States)

Mitchell, T.

2017-12-01

"Traditional" wetland physical assessment modules do not adequately identify Tribal cultural values of wetlands and thus wetlands may not be adequately protected for cultural uses. This Swinomish Wetlands Cultural Assessment Project has developed a cultural resource scoring module that can be incorporated into wetland assessments to better inform wetland protections. Local native knowledge was gathered about the traditional uses of 99 native wetland plant species. A cultural scoring matrix was developed based on the presence of traditionally used plants in several use categories including: construction, ceremonial, subsistence, medicinal, common use, plant rarity, and place of value for each wetland. The combined score of the cultural and physcial modules provides an overall wetland score that relates to proscribed buffer protection widths. With this local native knowledge incorporated into wetland assessments, we are protecting and preserving Swinomish Reservation wetlands for both cultural uses and ecological functionality through the Tribe's wetland protection law.

Water quality and aquatic communities of upland wetlands, Cumberland Island National Seashore, Georgia, April 1999 to July 2000

Science.gov (United States)

Frick, Elizabeth A.; Gregory, M. Brian; Calhoun, Daniel L.; Hopkins, Evelyn H.

2002-01-01

Cumberland Island is the southernmost and largest barrier island along the coast of Georgia. The island contains about 2,500 acres of freshwater wetlands that are located in a variety of physical settings, have a wide range of hydroperiods, and are influenced to varying degrees by surface and ground water, rainwater, and seawater. In 1999-2000, the U.S. Geological Survey, in cooperation with the National Park Service, conducted a water-quality study of Cumberland Island National Seashore to document and interpret the quality of a representative subset of surface- and ground-water resources for management of the seashore's natural resources. As part of this study, historical ground-water, surface-water, and ecological studies conducted on Cumberland Island also were summarized. Surface-water samples from six wetland areas located in the upland area of Cumberland Island were collected quarterly from April 1999 to March 2000 and analyzed for major ions, nutrients, trace elements, and field water-quality constituents including specific conductance, pH, temperature, dissolved oxygen, alkalinity, tannin and lignin, and turbidity. In addition, water temperature and specific conductance were recorded continuously from two wetland areas located near the mean high-tide mark on the Atlantic Ocean beaches from April 1999 to July 2000. Fish and invertebrate communities from six wetlands were sampled during April and December 1999. The microbial quality of the near-shore Atlantic Ocean was assessed in seawater samples collected for 5 consecutive days in April 1999 at five beaches near campgrounds where most recreational water contact occurs. Ground-water samples were collected from the Upper Floridan aquifer in April 1999 and from the surficial aquifer in April 2000 at 11 permanent wells and 4 temporary wells (drive points), and were analyzed for major ions, nutrients, trace elements, and field water-quality constituents (conductivity, pH, temperature, dissolved oxygen, and

Hydroclimate-driven changes in the landscape structure of the terminal lakes and wetlands of the China's Heihe River Basin.

Science.gov (United States)

Xiao, Shengchun; Xiao, Honglang; Peng, Xiaomei; Song, Xiang

2015-01-01

Changes in the landscape structure of terminal lakes and wetlands along inland rivers in arid areas are determined by the water balance in the river basins under the impacts of climate change and human activities. Studying the evolution of these landscapes and the mechanisms driving these changes is critical to the sustainable development of river basins. The terminal lakes and wetlands along the lower reaches of the Heihe River, an inland river in arid northwestern China, can be grouped into three types: runoff-recharged, groundwater-recharged, and precipitation-recharged. These water-recharge characteristics determine the degree to which the landscape structure of a terminal lake or wetland is impacted by climate change and human activities. An analysis of seven remote-sensing and hydroclimatic data sets for the Heihe River basin during the last 50 years indicates that hydrological changes in the basin caused by regional human activities were the primary drivers of the observed changes in the spatial and temporal landscape-structure patterns of the terminal lakes and wetlands of the Heihe River. In this warm, dry climatic context, the lakes and wetlands gradually evolved toward and maintained a landscape dominated by saline-alkaline lands and grasslands.

Fate of Uranium in Wetlands: Impact of Drought Followed by Re-flooding

Science.gov (United States)

Gilson, E.; Huang, S.; Koster van Groos, P. G.; Scheckel, K.; Peacock, A. D.; Kaplan, D. I.; Jaffe, P. R.

2014-12-01

Uranium contamination in groundwater can be mitigated in anoxic zones by iron-reducing bacteria that reduce soluble U(VI) to insoluble U(IV) and by uranium immobilization through complexation and sorption. Wetlands often link ground and surface-waters, making them strategic systems for potentially limiting migration of uranium contamination. Little is known about how drought periods that result in the drying of wetland soils, and consequent redox changes, affect uranium fate and transport in wetlands. In order to better understand the fate and stability of immobilized uranium in wetland soils, and how dry periods affect the uranium stability, we dosed saturated wetland mesocosms planted with Scirpus acutus with low levels of uranyl-acetate for 5 months before imposing a 9-day drying period followed by a 13-day rewetting period. Concentrations of uranium in mesocosm effluent increased after rewetting, but the cumulative amount of uranium released in the 13 days following the drying constituted less than 1% of the uranium immobilized in the soil during the 5 months prior to the drought. This low level of remobilization suggests that the uranium immobilized in these soils was not primarily bioreduced U(IV), which could have been oxidized to soluble U(VI) during the drought and released in the effluent during the subsequent flood. XANES analyses confirm that most of the uranium immobilized in the mesocosms was U(VI) sorbed to iron oxides. Compared to mesocosms that did not experience drying or rewetting, mesocosms that were sacrificed immediately after drying and after 13 days of rewetting had less uranium in soil near roots and more uranium on root surfaces. Metal-reducing bacteria only dominated the bacterial community after 13 days of rewetting and not immediately after drying, indicating that these bacteria are not responsible for this redistribution of uranium after the drying and rewetting. Results show that short periods of drought conditions in a wetland may

Proceedings of the 2010 PTAC soil and groundwater forum and poster session

International Nuclear Information System (INIS)

2010-01-01

This conference focused on emerging environmental issues and advances in soil and groundwater remediation research. It provided a forum to discuss current research and environmental regulations pertaining to the remediation and reclamation of oil and gas production sites as well as soils along pipeline routes. Methods for accurately identifying the source of hydrocarbon contamination in soils and wetlands were also presented. Recent advances in technological solutions for soil and groundwater remediation were reviewed along with methods for addressing salts, petroleum hydrocarbons, and process chemicals. The conference featured 18 presentations, of which 3 have been catalogued separately for inclusion in this database. refs., tabs., figs.

Land-Use Analysis and Simulated Effects of Land-Use Change and Aggregate Mining on Groundwater Flow in the South Platte River Valley, Brighton to Fort Lupton, Colorado

Science.gov (United States)

Arnold, L.R.; Mladinich, C.S.; Langer, W.H.; Daniels, J.S.

2010-01-01

Land use in the South Platte River valley between the cities of Brighton and Fort Lupton, Colo., is undergoing change as urban areas expand, and the extent of aggregate mining in the Brighton-Fort Lupton area is increasing as the demand for aggregate grows in response to urban development. To improve understanding of land-use change and the potential effects of land-use change and aggregate mining on groundwater flow, the U.S. Geological Survey, in cooperation with the cities of Brighton and Fort Lupton, analyzed socioeconomic and land-use trends and constructed a numerical groundwater flow model of the South Platte alluvial aquifer in the Brighton-Fort Lupton area. The numerical groundwater flow model was used to simulate (1) steady-state hydrologic effects of predicted land-use conditions in 2020 and 2040, (2) transient cumulative hydrologic effects of the potential extent of reclaimed aggregate pits in 2020 and 2040, (3) transient hydrologic effects of actively dewatered aggregate pits, and (4) effects of different hypothetical pit spacings and configurations on groundwater levels. The SLEUTH (Slope, Land cover, Exclusion, Urbanization, Transportation, and Hillshade) urban-growth modeling program was used to predict the extent of urban area in 2020 and 2040. Wetlands in the Brighton-Fort Lupton area were mapped as part of the study, and mapped wetland locations and areas of riparian herbaceous vegetation previously mapped by the Colorado Division of Wildlife were compared to simulation results to indicate areas where wetlands or riparian herbaceous vegetation might be affected by groundwater-level changes resulting from land-use change or aggregate mining. Analysis of land-use conditions in 1957, 1977, and 2000 indicated that the general distribution of irrigated land and non-irrigated land remained similar from 1957 to 2000, but both land uses decreased as urban area increased. Urban area increased about 165 percent from 1957 to 1977 and about 56 percent from

Evaluation of groundwater droughts in Austria

Science.gov (United States)

Haas, Johannes Christoph; Birk, Steffen

2015-04-01

Droughts are abnormally dry periods that affect various aspects of human life on earth, ranging from negative impacts on agriculture or industry, to being the cause for conflict and loss of human life. The changing climate reinforces the importance of investigations into this phenomenon. Various methods to analyze and classify droughts have been developed. These include drought indices such as the Standard Precipitation Index SPI, the Palmer Drought Severity Index PDSI or the Crop Moisture Index CMI. These and other indices consider meteorological parameters and/or their effects on soil moisture. A depletion of soil moisture triggered by low precipitation and high evapotranspiration may also cause reduced groundwater recharge and thus decreasing groundwater levels and reduced groundwater flow to springs, streams, and wetlands. However, the existing indices were generally not designed to address such drought effects on groundwater. Thus, a Standardized Groundwater level Index has recently been proposed by Bloomfied and Marchant (2013). Yet, to our knowledge, this approach has only been applied to consolidated aquifers in the UK. This work analyzes time series of groundwater levels from various, mostly unconsolidated aquifers in Austria in order to characterize the effects of droughts on aquifers in different hydrogeologic and climatic settings as well as under different usage scenarios. In particular, comparisons are made between the water rich Alpine parts of Austria, and the dryer parts situated in the East. The time series of groundwater levels are compared to other data, such as meteorological time series and written weather records about generally accepted phenomena, such as the 2003 European drought and heat wave. Thus, valuable insight is gained into the propagation of meteorological droughts through the soil and the aquifer in different types of hydrogeologic and climatic settings, which provides a prerequisite for the assessment of the aquifers' drought

Introduction to the Wetland Book 1: Wetland structure and function, management, and nethods

Science.gov (United States)

Davidson, Nick C.; Middleton, Beth A.; McInnes, Robert J.; Everard, Mark; Irvine, Kenneth; Van Dam, Anne A.; Finlayson, C. Max; Finlayson, C. Max; Everard, Mark; Irvine, Kenneth; McInnes, Robert J.; Middleton, Beth A.; Van Dam, Anne A.; Davidson, Nick C.

2016-01-01

The Wetland Book 1 is designed as a ‘first port-of-call’ reference work for information on the structure and functions of wetlands, current approaches to wetland management, and methods for researching and understanding wetlands. Contributions by experts summarize key concepts, orient the reader to the major issues, and support further research on such issues by individuals and multidisciplinary teams. The Wetland Book 1 is organized in three parts - Wetland structure and function; Wetland management; and Wetland methods - each of which is divided into a number of thematic Sections. Each Section starts with one or more overview chapters, supported by chapters providing further information and case studies on different aspects of the theme.

Relating zoobenthic and emergent terrestrial insect production to tree swallow (Tachycineta bicolor) nestling diet in oil sands wetlands

Energy Technology Data Exchange (ETDEWEB)

Thoms, J.L.; Martin, J.P.; Ciborowski, J.J. [Windsor Univ., Windsor, ON (Canada); Harms, N.J.; Smits, J.E. [Saskatchewan Univ., Saskatoon, SK (Canada)

2009-07-01

This study examined the influence of oil sands process materials (OSPM) on wetland macroinvertebrate community composition and production. Tree swallows are known to inhabit constructed nest boxes and forage near their nest on flying insects of terrestrial and aquatic origin. Therefore, this study evaluated the structure of wetland food webs and how it relates to the transfer of production from aquatic sediments to nestling tree swallows. The study involved 2 reference and 2 oil sands affected wetlands. Exuviae of emerging aquatic and flying insects from floating and sticky traps were collected every 3 days during the tree swallow nestling period in order to estimate benthic invertebrate composition and production. The tree swallow nest boxes, placed around the perimeter of the wetlands in spring were monitored during egg laying and incubation. Diets of the 10-14 day-old nestlings were determined by placing a ligature around the neck of each nestling, preventing the passage of food into the esophagus for 45 min. Food boluses were collected from nestlings fed by the parents during that time. The study showed that although oil sands-affected wetlands had lower aerial insect abundance, they represented over half of the total boluses collected. It was concluded that this study will help determine the ecological viability of oil sands-affected wetlands and their capability of supporting terrestrial predators that rely on zoobenthos.

Importance of Macrophyte Quality in Determining Life-History Traits of the Apple Snails Pomacea canaliculata: Implications for Bottom-Up Management of an Invasive Herbivorous Pest in Constructed Wetlands

Science.gov (United States)

Yam, Rita S. W.; Fan, Yen-Tzu; Wang, Tzu-Ting

2016-01-01

Pomacea canaliculata (Ampullariidae) has extensively invaded most Asian constructed wetlands and its massive herbivory of macrophytes has become a major cause of ecosystem dysfunctioning of these restored habitats. We conducted non-choice laboratory feeding experiments of P. canaliculata using five common macrophyte species in constructed wetlands including Ipomoea aquatica, Commelina communis, Nymphoides coreana, Acorus calamus and Phragmites australis. Effects of macrophytes on snail feeding, growth and fecundity responses were evaluated. Results indicated that P. canaliculata reared on Ipomoea had the highest feeding and growth rates with highest reproductive output, but all individuals fed with Phragmites showed lowest feeding rates and little growth with poorest reproductive output. Plant N and P contents were important for enhancing palatability, supporting growth and offspring quantity of P. canaliculata, whilst toughness, cellulose and phenolics had critically deterrent effects on various life-history traits. Although snail offspring quality was generally consistent regardless of maternal feeding conditions, the reduced growth and offspring quantity of the poorly-fed snails in constructed wetlands dominated by the less-palatable macrophytes could limit the invasive success of P. canaliculata. Effective bottom-up control of P. canaliculata in constructed wetlands should involve selective planting strategy using macrophytes with low nutrient and high toughness, cellulose and phenolic contents. PMID:26927135

Importance of Macrophyte Quality in Determining Life-History Traits of the Apple Snails Pomacea canaliculata: Implications for Bottom-Up Management of an Invasive Herbivorous Pest in Constructed Wetlands

Directory of Open Access Journals (Sweden)

Rita S. W. Yam

2016-02-01

Full Text Available Pomacea canaliculata (Ampullariidae has extensively invaded most Asian constructed wetlands and its massive herbivory of macrophytes has become a major cause of ecosystem dysfunctioning of these restored habitats. We conducted non-choice laboratory feeding experiments of P. canaliculata using five common macrophyte species in constructed wetlands including Ipomoea aquatica, Commelina communis, Nymphoides coreana, Acorus calamus and Phragmites australis. Effects of macrophytes on snail feeding, growth and fecundity responses were evaluated. Results indicated that P. canaliculata reared on Ipomoea had the highest feeding and growth rates with highest reproductive output, but all individuals fed with Phragmites showed lowest feeding rates and little growth with poorest reproductive output. Plant N and P contents were important for enhancing palatability, supporting growth and offspring quantity of P. canaliculata, whilst toughness, cellulose and phenolics had critically deterrent effects on various life-history traits. Although snail offspring quality was generally consistent regardless of maternal feeding conditions, the reduced growth and offspring quantity of the poorly-fed snails in constructed wetlands dominated by the less-palatable macrophytes could limit the invasive success of P. canaliculata. Effective bottom-up control of P. canaliculata in constructed wetlands should involve selective planting strategy using macrophytes with low nutrient and high toughness, cellulose and phenolic contents.

Importance of Macrophyte Quality in Determining Life-History Traits of the Apple Snails Pomacea canaliculata: Implications for Bottom-Up Management of an Invasive Herbivorous Pest in Constructed Wetlands.

Science.gov (United States)

Yam, Rita S W; Fan, Yen-Tzu; Wang, Tzu-Ting

2016-02-24

Pomacea canaliculata (Ampullariidae) has extensively invaded most Asian constructed wetlands and its massive herbivory of macrophytes has become a major cause of ecosystem dysfunctioning of these restored habitats. We conducted non-choice laboratory feeding experiments of P. canaliculata using five common macrophyte species in constructed wetlands including Ipomoea aquatica, Commelina communis, Nymphoides coreana, Acorus calamus and Phragmites australis. Effects of macrophytes on snail feeding, growth and fecundity responses were evaluated. Results indicated that P. canaliculata reared on Ipomoea had the highest feeding and growth rates with highest reproductive output, but all individuals fed with Phragmites showed lowest feeding rates and little growth with poorest reproductive output. Plant N and P contents were important for enhancing palatability, supporting growth and offspring quantity of P. canaliculata, whilst toughness, cellulose and phenolics had critically deterrent effects on various life-history traits. Although snail offspring quality was generally consistent regardless of maternal feeding conditions, the reduced growth and offspring quantity of the poorly-fed snails in constructed wetlands dominated by the less-palatable macrophytes could limit the invasive success of P. canaliculata. Effective bottom-up control of P. canaliculata in constructed wetlands should involve selective planting strategy using macrophytes with low nutrient and high toughness, cellulose and phenolic contents.

Reduction of neonicotinoid insecticide residues in Prairie wetlands by common wetland plants.

Science.gov (United States)

Main, Anson R; Fehr, Jessica; Liber, Karsten; Headley, John V; Peru, Kerry M; Morrissey, Christy A

2017-02-01

Neonicotinoid insecticides are frequently detected in wetlands during the early to mid-growing period of the Canadian Prairie cropping season. These detections also overlap with the growth of macrophytes that commonly surround agricultural wetlands which we hypothesized may reduce neonicotinoid transport and retention in wetlands. We sampled 20 agricultural wetlands and 11 macrophyte species in central Saskatchewan, Canada, over eight weeks to investigate whether macrophytes were capable of reducing movement of neonicotinoids from cultivated fields and/or reducing concentrations in surface water by accumulating insecticide residues into their tissues. Study wetlands were surrounded by clothianidin-treated canola and selected based on the presence (n=10) or absence (n=10) of a zonal plant community. Neonicotinoids were positively detected in 43% of wetland plants, and quantified in 8% of all plant tissues sampled. Three plant species showed high rates of detection: 78% Equisetum arvense (clothianidin, range: wetlands had higher detection frequency and water concentrations of clothianidin (β±S.E.: -0.77±0.26, P=0.003) and thiamethoxam (β±S.E.: -0.69±0.35, P=0.049) than vegetated wetlands. We assessed the importance of wetland characteristics (e.g. vegetative zone width, emergent plant height, water depth) on neonicotinoid concentrations in Prairie wetlands over time using linear mixed-effects models. Clothianidin concentrations were significantly lower in wetlands surrounded by taller plants (β±S.E.: -0.57±0.12, P≤0.001). The results of this study suggest that macrophytes can play an important role in mitigating water contamination by accumulating neonicotinoids and possibly slowing transport to wetlands during the growing season. Copyright © 2016 Elsevier B.V. All rights reserved.

Mapping and quantifying groundwater inflows to Deep Creek (Maribyrnong catchment, SE Australia) using 222Rn, implications for protecting groundwater-dependant ecosystems

International Nuclear Information System (INIS)

Cartwright, Ian; Gilfedder, Benjamin

2015-01-01

Highlights: • Groundwater inflows in a chain-of-ponds river quantified. • Groundwater inflow vs. discharge relationship determined using Rn. • First long-term continuous Rn monitoring in a river indicates temporal changes to groundwater inflows. • Application to protection of groundwater-dependant ecosystems. - Abstract: Understanding groundwater inflows to rivers is important in managing connected groundwater and surface water systems and for protecting groundwater-dependant ecosystems. This study defines the distribution of gaining reaches and estimates groundwater inflows to a 62 km long section of Deep Creek (Maribyrnong catchment, Australia) using 222 Rn. During summer months, Deep Creek ceases to flow and comprises a chain of ponds that δ 18 O and δ 2 H values, major ion concentrations, and 222 Rn activities imply are groundwater fed. During the period where the river flows, the relative contribution of groundwater inflows to total river discharge ranges from ∼14% at high flow conditions to ∼100% at low flows. That the predicted groundwater inflows account for all of the increase in discharge at low flow conditions lends confidence to the mass balance calculations. Near-continuous 27 week 222 Rn monitoring at one location in the middle of the catchment confirms the inverse correlation between river discharge and relative groundwater inflows, and also implies that there are limited bank return flows. Variations in groundwater inflows are related to geology and topography. High groundwater inflows occur where the river is at the edge of its floodplain, adjacent to hills composed of basement rocks, or flowing through steep incised valleys. Understanding the distribution of groundwater inflows and quantifying the contribution of groundwater to Deep Creek is important for managing and protecting the surface water resources, which support the endangered Yarra pygmy perch

Iron mineralogy and uranium-binding environment in the rhizosphere of a wetland soil

Energy Technology Data Exchange (ETDEWEB)

Kaplan, Daniel I., E-mail: daniel.kaplan@srnl.doe.gov [Savannah River National Laboratory, Aiken, SC 29808 (United States); Kukkadapu, Ravi [Environmental Molecular Sciences Laboratory, Pacific Northwest National Laboratory, Richland, WA 99354 (United States); Seaman, John C. [Savannah River Ecology Laboratory, University of Georgia, Aiken, SC 29802 (United States); Arey, Bruce W.; Dohnalkova, Alice C. [Environmental Molecular Sciences Laboratory, Pacific Northwest National Laboratory, Richland, WA 99354 (United States); Buettner, Shea [Savannah River Ecology Laboratory, University of Georgia, Aiken, SC 29802 (United States); Li, Dien [Savannah River National Laboratory, Aiken, SC 29808 (United States); Varga, Tamas [Environmental Molecular Sciences Laboratory, Pacific Northwest National Laboratory, Richland, WA 99354 (United States); Scheckel, Kirk G. [US Environmental Protection Agency, National Risk Management Research Laboratory, Cincinnati, OH 45224 (United States); Jaffé, Peter R. [Princeton University, Princeton, NJ 08540 (United States)

2016-11-01

Wetlands mitigate the migration of groundwater contaminants through a series of biogeochemical gradients that enhance multiple contaminant-binding processes. The hypothesis of this study was that wetland plant roots contribute organic carbon and release O{sub 2} within the rhizosphere (plant-impact soil zone) that promote the formation of Fe(III)-(oxyhydr)oxides. In turn, these Fe(III)-(oxyhydr)oxides stabilize organic matter that together contribute to contaminant immobilization. Mineralogy and U binding environments of the rhizosphere were evaluated in samples collected from contaminated and non-contaminated areas of a wetland on the Savannah River Site in South Carolina. Based on Mössbauer spectroscopy, rhizosphere soil was greatly enriched with nanogoethite, ferrihydrite-like nanoparticulates, and hematite, with negligible Fe(II) present. X-ray computed tomography and various microscopy techniques showed that root plaques were tens-of-microns thick and consisted of highly oriented Fe-nanoparticles, suggesting that the roots were involved in creating the biogeochemical conditions conducive to the nanoparticle formation. XAS showed that a majority of the U in the bulk wetland soil was in the + 6 oxidation state and was not well correlated spatially to Fe concentrations. SEM/EDS confirm that U was enriched on root plaques, where it was always found in association with P. Together these findings support our hypothesis and suggest that plants can alter mineralogical conditions that may be conducive to contaminant immobilization in wetlands. - Highlights: • Uranium concentrated in wetland environments • Hypothesized that plant roots change mineralogy and contaminant binding environment, promoting contaminant immobilization • Field study showed sharp dissolved U concentration profiles over the centimeter scale. • Spectroscopy identified unique mineralogy in rhizosphere compared to non-rhizosphere soil. • Uranium concentrated in root plaques in the + 6

Iron mineralogy and uranium-binding environment in the rhizosphere of a wetland soil

International Nuclear Information System (INIS)

Kaplan, Daniel I.; Kukkadapu, Ravi; Seaman, John C.; Arey, Bruce W.; Dohnalkova, Alice C.; Buettner, Shea; Li, Dien; Varga, Tamas; Scheckel, Kirk G.; Jaffé, Peter R.

2016-01-01

Wetlands mitigate the migration of groundwater contaminants through a series of biogeochemical gradients that enhance multiple contaminant-binding processes. The hypothesis of this study was that wetland plant roots contribute organic carbon and release O_2 within the rhizosphere (plant-impact soil zone) that promote the formation of Fe(III)-(oxyhydr)oxides. In turn, these Fe(III)-(oxyhydr)oxides stabilize organic matter that together contribute to contaminant immobilization. Mineralogy and U binding environments of the rhizosphere were evaluated in samples collected from contaminated and non-contaminated areas of a wetland on the Savannah River Site in South Carolina. Based on Mössbauer spectroscopy, rhizosphere soil was greatly enriched with nanogoethite, ferrihydrite-like nanoparticulates, and hematite, with negligible Fe(II) present. X-ray computed tomography and various microscopy techniques showed that root plaques were tens-of-microns thick and consisted of highly oriented Fe-nanoparticles, suggesting that the roots were involved in creating the biogeochemical conditions conducive to the nanoparticle formation. XAS showed that a majority of the U in the bulk wetland soil was in the + 6 oxidation state and was not well correlated spatially to Fe concentrations. SEM/EDS confirm that U was enriched on root plaques, where it was always found in association with P. Together these findings support our hypothesis and suggest that plants can alter mineralogical conditions that may be conducive to contaminant immobilization in wetlands. - Highlights: • Uranium concentrated in wetland environments • Hypothesized that plant roots change mineralogy and contaminant binding environment, promoting contaminant immobilization • Field study showed sharp dissolved U concentration profiles over the centimeter scale. • Spectroscopy identified unique mineralogy in rhizosphere compared to non-rhizosphere soil. • Uranium concentrated in root plaques in the + 6 oxidation

Characterisation of the hydrology of an estuarine wetland

Science.gov (United States)

Hughes, Catherine E.; Binning, Philip; Willgoose, Garry R.

1998-11-01

The intertidal zone of estuarine wetlands is characterised by a transition from a saline marine environment to a freshwater environment with increasing distance from tidal streams. An experimental site has been established in an area of mangrove and salt marsh wetland in the Hunter River estuary, Australia, to characterise and provide data for a model of intertidal zone hydrology. The experimental site is designed to monitor water fluxes at a small scale (36 m). A weather station and groundwater monitoring wells have been installed and hydraulic head and tidal levels are monitored over a 10-week period along a short one-dimensional transect covering the transition between the tidal and freshwater systems. Soil properties have been determined in the laboratory and the field. A two-dimensional finite element model of the site was developed using SEEP/W to analyse saturated and unsaturated pore water movement. Modification of the water retention function to model crab hole macropores was found necessary to reproduce the observed aquifer response. Groundwater response to tidal fluctuations was observed to be almost uniform beyond the intertidal zone, due to the presence of highly permeable subsurface sediments below the less permeable surface sediments. Over the 36 m transect, tidal forcing was found to generate incoming fluxes in the order of 0.22 m 3/day per metre width of creek bank during dry periods, partially balanced by evaporative fluxes of about 0.13 m 3/day per metre width. During heavy rainfall periods, rainfall fluxes were about 0.61 m 3/day per metre width, dominating the water balance. Evapotranspiration rates were greater for the salt marsh dominated intertidal zone than the non-tidal zone. Hypersalinity and salt encrustation observed show that evapotranspiration fluxes are very important during non-rainfall periods and are believed to significantly influence salt concentration both in the surface soil matrix and the underlying aquifer.

Algal Bio-Indication in Assessment of Hydrological Impact on Ecosystem in Wetlands of “Slavyansky Resort”

Directory of Open Access Journals (Sweden)

Klymiuk Valentina

2015-06-01

Full Text Available Algal bio-indication is commonly used in water quality assessment but can also help in assessing the impact of hydrology on freshwater wetland ecosystems.We identified 350 species and infraspecific taxa of algae from nine taxonomic divisions (Cyanoprokaryota, Chrysophyta, Euglenophyta,Dinophyta,Xanthophyta,Cryptophyta,Bacillariophyta,Chlorophyta,Charophyta in 121 phytoplankton samples collected between 2007-2013 from seven lakes in the wetlands of the Regional Landscape Park “Slavyansky Resort”, Ukraine. The algal species richness and phytoplankton biomass decreased as water salinity increased. In turn the water salinity was influenced by the inflow of groundwater, karst fracture and by the alluvial water tributaries of a paleoriver that affects the formation processes of lake-spring sulphide mud from the resort, which is often used for therapeutic purposes.

Constructed Wetlands

Science.gov (United States)

these systems can improve water quality, engineers and scientists construct systems that replicate the functions of natural wetlands. Constructed wetlands are treatment systems that use natural processes

"Wetlands: Water Living Filters?",

OpenAIRE

Dordio, Ana; Palace, A. J.; Pinto, Ana Paula

2008-01-01

Human societies have indirectly used natural wetlands as wastewater discharge sites for many centuries. Observations of the wastewater depuration capacity of natural wetlands have led to a greater understanding of the potential of these ecosystems for pollutant assimilation and have stimulated the development of artificial wetlands systems for treatment of wastewaters from a variety of sources. Constructed wetlands, in contrast to natural wetlands, are human-made systems that are designed, bu...

The dynamics of low-chlorinated benzenes in a pilot-scale constructed wetland and a hydroponic plant root mat treating sulfate-rich groundwater.

Science.gov (United States)

Chen, Zhongbing; Kuschk, Peter; Paschke, Heidrun; Kästner, Matthias; Köser, Heinz

2015-03-01

A rarely used hydroponic plant root mat filter (PRMF, of 6 m(2)) and a horizontal subsurface flow constructed wetland (HSSF CW, of 6 m(2)), operating in continuous flow and discontinuous outflow flushing modes, were investigated for treating sulfate-rich and organic carbon-lean groundwater contaminated with monochlorobenzene (MCB); 1,2-dichlorobenzene (1,2-DCB); 1,4-dichlorobenzene (1,4-DCB); and 2-chlorotoluene. Whereas the mean inflow loads ranged from 1 to 247 mg m(-2) days(-1), the range of mean inflow concentrations of the chlorobenzenes recorded over a period of 7 months was within 0.04 and 8 mg L(-1). A hydraulic surface loading rate of 30 L m(-2) days(-1) was obtained in both systems. The mean load removal efficiencies were found to vary between 87 and 93 % in the PRMF after a flow path of 4 m, while the removal efficiencies were found to range between 46 and 70 % and 71 to 73 % in the HSSF CW operating in a continuous flow mode and a discontinuous outflow flushing mode, respectively. Seasonal variations in the removal efficiencies were observed for all low-chlorinated hydrocarbons both in the PRMF and the HSSF CW, whereby the highest removal efficiencies were reached during the summer months. Sulfide formation occurred in the organic carbon-lean groundwater particularly in summer, which is probably due to the plant-derived organic carbon that fostered the microbial dissimilatory sulfate reduction. Higher redox potential in water was observed in the PRMF. In conclusion, the PRMF could be an option for the treatment of water contaminated with compounds which in particular need oxic conditions for their microbial degradation, such as in the case of low-chlorinated benzenes.

A high resolution global scale groundwater model

Science.gov (United States)

de Graaf, Inge; Sutanudjaja, Edwin; van Beek, Rens; Bierkens, Marc

2014-05-01

As the world's largest accessible source of freshwater, groundwater plays a vital role in satisfying the basic needs of human society. It serves as a primary source of drinking water and supplies water for agricultural and industrial activities. During times of drought, groundwater storage provides a large natural buffer against water shortage and sustains flows to rivers and wetlands, supporting ecosystem habitats and biodiversity. Yet, the current generation of global scale hydrological models (GHMs) do not include a groundwater flow component, although it is a crucial part of the hydrological cycle. Thus, a realistic physical representation of the groundwater system that allows for the simulation of groundwater head dynamics and lateral flows is essential for GHMs that increasingly run at finer resolution. In this study we present a global groundwater model with a resolution of 5 arc-minutes (approximately 10 km at the equator) using MODFLOW (McDonald and Harbaugh, 1988). With this global groundwater model we eventually intend to simulate the changes in the groundwater system over time that result from variations in recharge and abstraction. Aquifer schematization and properties of this groundwater model were developed from available global lithological maps and datasets (Dürr et al., 2005; Gleeson et al., 2010; Hartmann and Moosdorf, 2013), combined with our estimate of aquifer thickness for sedimentary basins. We forced the groundwater model with the output from the global hydrological model PCR-GLOBWB (van Beek et al., 2011), specifically the net groundwater recharge and average surface water levels derived from routed channel discharge. For the parameterization, we relied entirely on available global datasets and did not calibrate the model so that it can equally be expanded to data poor environments. Based on our sensitivity analysis, in which we run the model with various hydrogeological parameter settings, we observed that most variance in groundwater

Hydrological behavior of coastal lagoons associated to wetlands, an example from southernmost bahía Samborombón (Argentina).

Science.gov (United States)

Tejada Tejada, Macarena; Carol, Eleanora; Galliari, Julieta; Richiano, Sebastian

2017-04-01

Coastal wetlands are located at a critical interface between the terrestrial and marine environments and are ideally positioned to reduce impacts from land-based sources. At the southern region of Bahía Samborombón (Argentina) the wetlands includes several small coastal lagoons developed inside of a sandy spike. The main object of this work is to analyze the hydrological behavior of the lagoons evaluating their role in the maintenances of the wetland. In order to do this, satellite image analysis was performed to identify the marshy areas, drainage features, morphology and connections of the lagoons, both with the tidal flows from the Río de la Plata estuary and from the Argentine Sea. Field surveys were carried out in one of the lagoons to define their geological and geomorphological characteristics. After that, a monitoring network was designed for sampling the superficial and the underground water, additionally electrical conductivity and pH of the water were determined in situ. In all the water samples extracted the content of majority ions was determined by standard methods. Complementary, sedimentological and malacological aspects were observed at several stations in the lagoon. The obtained results allow us to recognize that the tidal flow that enters from the sea, at least in the studied lagoon, is the main hydrological sustenance of the wetland. This flow enters mainly using one tidal channel which connects (in a semi-permanent way) the sea with the lagoon during extraordinary tide and storm events. During low tide the lagoon loses connection and the drainage towards the sea is scarce. The tidal water that accumulates in the lagoon is subsequently evaporated causing an increase in the salinity of the surface water to values higher than the sea. Groundwater that accumulates through the infiltration of rainfall in the sandy sediments of the spike also discharges to the lagoon and supports the wetland surrounding the coastal lagoon. This flow, even when it

Deletion of groundwater from a disposal facility in Laxemar. Description of the consequences for nature values and production land; Bortledande av grundvatten fraan en slutfoervarsanlaeggning i Laxemar. Beskrivning av konsekvenser foer naturvaerden och produktionsmark

Energy Technology Data Exchange (ETDEWEB)

Hamren, Ulrika; Collinder, Per; Allmer, Johan (Ekologigruppen AB, Stockholm (Sweden))

2010-10-15

SKB has chosen Forsmark in the municipality of Oesthammar as site for the repository for spent nuclear fuel. This report describes consequences for nature values, agriculture and forestry due to groundwater diversion from a repository at the non-chosen Laxemar site in the municipality of Oskarshamn. The report concerns nature values that depend on, or are favoured by, a groundwater table close to or above the ground surface. Laxemar is a valuable area from a nature conservation point of view, primarily associated to the cultural- and forest landscape and its prior use for pasture and hay-making. Hence, these values depend on factors other than the level of the groundwater table. Except for old pastures and haymaking areas, many high nature values consist of hardwood-forest groves and old solitary deciduous trees. 67 groundwater-dependent or groundwater-favoured nature objects (wetlands, pieces of forest and surface water) are identified in the investigated area. No nature object is judged to have national value (class 1). 15 nature objects (pieces of forest) are judged to have regional value (class 2), 18 have municipal value (class 3) and 34 local value (class 4). It is judged that a drawdown of the groundwater table only would result in small consequences for the nature values of the area in its entirety. The nature objects that would be affected by the largest groundwater-table drawdown have relatively low nature values and consist of small wetlands with local value (class 4). The low nature values of these objects imply that the consequences of the groundwater diversion would be small. Nature objects with higher nature values (regional or municipal value) consist of forest key habitats and ancient pastures on previously argued land. The nature values of these objects are hence dependent on factors other than the level of the groundwater table, which implies that the consequences would be small also for these objects. The consequences would be largest

Wetlands - different types, their properties and functions

International Nuclear Information System (INIS)

Kellner, Erik

2003-08-01

In this report, different Swedish wetland types are presented with emphasis on their occurrence, vegetation cover, soil physical and chemical properties and functions. Three different main groups of wetlands are identified: bogs, fens and marshes. The former two are peat forming environments while the term 'marshes' covers all non-peat forming wetlands. Poor fens are the most common type in Sweden but (tree-covered) marshes would probably be dominating large areas in Southern Sweden if not affected by human activity such as drainage for farming. Fens and bogs are often coexisting next to each other and bogs are often seen to be the next step after fens in the natural succession. However, the development of wetlands and processes of succession between different wetland types are resulting from complicated interactions between climate, vegetation, geology and topography. For description of the development at individual sites, the hydrological settings which determine the water flow paths seem to be most crucial, emphasizing the importance of geology and topography. For modelling the growth of peat, simple models have so far dominated, but these are often restricted in general use. Therefore, more physical-based models have been developed, but the natural heterogeneity and climate shifts bring uncertainty of how they should be parameterised. The use of coupled groundwater-substance transport models have shown to help understand how water flows and soil chemistry are developing in response to different peat forms. The peat is characterised by a high porosity (80-95%) which is decreasing with decomposition and depth. The most important change is then that the actively conducting pores are getting clogged and closed. The storage coefficient of the peat is then decreasing with decomposition as well as the hydraulic conductivity. The variation of hydraulic conductivity (k) can be large and current understanding of the connections between hydraulic conductivity and other

Wetlands - different types, their properties and functions

Energy Technology Data Exchange (ETDEWEB)

Kellner, Erik [Uppsala Univ. (Sweden). Dept. of Earth Sciences/Hydrology

2003-08-01

In this report, different Swedish wetland types are presented with emphasis on their occurrence, vegetation cover, soil physical and chemical properties and functions. Three different main groups of wetlands are identified: bogs, fens and marshes. The former two are peat forming environments while the term 'marshes' covers all non-peat forming wetlands. Poor fens are the most common type in Sweden but (tree-covered) marshes would probably be dominating large areas in Southern Sweden if not affected by human activity such as drainage for farming. Fens and bogs are often coexisting next to each other and bogs are often seen to be the next step after fens in the natural succession. However, the development of wetlands and processes of succession between different wetland types are resulting from complicated interactions between climate, vegetation, geology and topography. For description of the development at individual sites, the hydrological settings which determine the water flow paths seem to be most crucial, emphasizing the importance of geology and topography. For modelling the growth of peat, simple models have so far dominated, but these are often restricted in general use. Therefore, more physical-based models have been developed, but the natural heterogeneity and climate shifts bring uncertainty of how they should be parameterised. The use of coupled groundwater-substance transport models have shown to help understand how water flows and soil chemistry are developing in response to different peat forms. The peat is characterised by a high porosity (80-95%) which is decreasing with decomposition and depth. The most important change is then that the actively conducting pores are getting clogged and closed. The storage coefficient of the peat is then decreasing with decomposition as well as the hydraulic conductivity. The variation of hydraulic conductivity (k) can be large and current understanding of the connections between hydraulic conductivity

Emulation of recharge and evapotranspiration processes in shallow groundwater systems

Science.gov (United States)

Doble, Rebecca C.; Pickett, Trevor; Crosbie, Russell S.; Morgan, Leanne K.; Turnadge, Chris; Davies, Phil J.

2017-12-01

In shallow groundwater systems, recharge and evapotranspiration are highly sensitive to changes in the depth to water table. To effectively model these fluxes, complex functions that include soil and vegetation properties are often required. Model emulation (surrogate modelling or meta-modelling) can provide a means of incorporating detailed conceptualisation of recharge and evapotranspiration processes, while maintaining the numerical tractability and computational performance required for regional scale groundwater models and uncertainty analysis. A method for emulating recharge and evapotranspiration processes in groundwater flow models was developed, and applied to the South East region of South Australia and western Victoria, which is characterised by shallow groundwater, wetlands and coastal lakes. The soil-vegetation-atmosphere transfer (SVAT) model WAVES was used to generate relationships between net recharge (diffuse recharge minus evapotranspiration from groundwater) and depth to water table for different combinations of climate, soil and land cover types. These relationships, which mimicked previously described soil, vegetation and groundwater behaviour, were combined into a net recharge lookup table. The segmented evapotranspiration package in MODFLOW was adapted to select values of net recharge from the lookup table depending on groundwater depth, and the climate, soil and land use characteristics of each cell. The model was found to be numerically robust in steady state testing, had no major increase in run time, and would be more efficient than tightly-coupled modelling approaches. It made reasonable predictions of net recharge and groundwater head compared with remotely sensed estimates of net recharge and a standard MODFLOW comparison model. In particular, the method was better able to predict net recharge and groundwater head in areas with steep hydraulic gradients.

Implementation of a permeable reactive barrier for treatment of groundwater impacted by strontium-90

International Nuclear Information System (INIS)

Przepiora, A.; Bodine, D.; Dollar, P.; Smith, P.

2014-01-01

A funnel and gate permeable reactive barrier (PRB) system was constructed to treat strontium-90 (Sr- 90) in groundwater migrating from a legacy waste disposal area into an adjacent wetland. The PRB system was designed to contain and direct the Sr-90 impacted groundwater into treatment 'gates' containing zeolite using a low permeability 'funnel' sections constructed with soil-bentonite slurry. The constructed PRB met all dimension and permeability specifications. Initial performance monitoring results indicate that the PRB captured the Sr-90 impacted groundwater plume and the beta radiation values in groundwater emerging from the treatment gates ranged from 35 to 86 Becquerel's per litre (Bq/L), equivalent to a reduction by 88% to 99% from the influent values. Those initial performance results were influenced by residual impacts present in the aquifer material prior to PRB installation. It is anticipated that the clean-up target of 5 Bq/L will be achieved with time as treated groundwater emerging from the PRB flushes through the downgradient aquifer zone. (author)

Metro Multnomah Wetlands - Multnomah Channel Wetland Restoration Monitoring Project

Data.gov (United States)

National Oceanic and Atmospheric Administration, Department of Commerce — The Multnomah Channel Wetland Restoration Monitoring Project characterizes wetlands use by juvenile salmonids and other fishes in the Multnomah Channel Marsh Natural...

Quarterly sampling of the wetlands along the old F-Area effluent ditch: March 1994

International Nuclear Information System (INIS)

Dixon, K.L.; Cummins, C.L.; Rogers, V.A.

1994-05-01

In March 1994, well point water and near surface water (bucket) samples were collected to further characterize tritium and volatile organic compounds (VOC) in the wetlands along the old F-Area effluent ditch south of 643-E (old burial ground). Groundwater flow paths suggest that compounds detected in water table wells around 643-E would migrate towards the old F-Area effluent ditch and Fourmile Branch. Recent analytical results from near surface water sampling in the wetlands that comprise the old F-Area effluent ditch have shown that tritium and small quantities of VOCs are outcropping in the area. Results of the March 1994 sampling event further support findings that tritium and volatile organic compounds originating from 643-E are outcropping in the wetlands near the old F-Area effluent ditch. Six different analytes were detected in the well points at least once at concentrations greater than the method detection limit: d 1,2-dichloroethylene, acetone, methyl ethyl ketone, tetrachloroethylene, trichloroethylene, and tritium. 1,2-dichloroethylene, tetrachloroethylene, trichloroethylene, and tritium were detected at levels above Primary Drinking Water Standards or Maximum Contaminant Levels list. Four analytes, 1,2-dichloroethylene, trichloroethylene, tritium, and vinyl chloride, were detected at least once at concentrations greater than the method detection limit and least once at concentrations above the PDWS or the MCL. Based on differences in tritium concentrations at each location, it was determined that the sampling devices intercepted different groundwater flow paths. This negated direct comparison of analytical results between devices. However, when VOC concentrations measured at each well point and bucket location were normalized, resulting well point and bucket VOC concentrations were comparable in most cases. These results suggest that volatilization losses of VOCs from the buckets were negligible

Wetlands: The changing regulatory landscape

International Nuclear Information System (INIS)

Glick, R.M.

1993-01-01

Protection of wetlands became a national issue in 1988 when President George Bush pledged no net loss of wetlands in the US under his open-quotes environmental presidency.close quotes As wetlands became a national issue, the job of protecting them became an obligation for many groups, including hydro-power developers. Now, when a site selected for development includes an area that may be classified as a wetland, the developer quickly discovers the importance of recognizing and protecting these natural habitats. Federal legislation severely limits development of wetland, and most states increase the restrictions with their own wetlands regulations. The difficulty of defining wetlands complicates federal and state enforcement. Land that appears to be dry may in fact be classified as a wetland. So, even if a site appears dry, potential hydro developers must confirm whether or not any jurisdictional wetlands are present. Regulated lands include much more than marshes and swamps. Further complicating the definition of wetlands, a recent court decision found that even artificially created wetlands, such as man-made ponds, may be subject to regulation. Hydro developers must be aware of current regulatory requirements before they consider development of any site that may contain wetlands. To be certain that a site is open-quotes buildableclose quotes from the standpoint of wetlands regulation, a developer must verify (with the help of state agencies) that the property does not contain any jurisdictional wetlands. If it does, the regulatory process before development becomes much more complicated. For the short term, uncertainty abounds and extreme caution is in order. Because the regulatory process has become so complex and an agreeable definition of wetlands so elusive, the trend among the Corps and collaborating agencies is to constrict nationwide permits in favor of narrowing the jurisdictional definition of wetlands

Evaluation of the Marine Intrusion in Havana Province Groundwater Using Hydrochemical and Isotopic Tools

Energy Technology Data Exchange (ETDEWEB)

Alvarez, A. M.; Bombuse, D. L.; Estevez Alvarez, J. R. [Centro de Aplicaciones Tecnologicas y Desarrollo Nuclear (CEADEN), Havana (Cuba); others, and

2013-07-15

In the present paper the spatial distribution and temporal evolution of the saline intrusion in the most important aquifer of Havana province is presented. Results were obtained through the application of hydrochemical and isotopic tools. Studies were carried out within the framework of the IAEA Regional Project RLA/8/041. The survey was carried out in 2008 during the dry and rainy seasons. Sampling points were selected according to a monitoring network located along the north-south line following the main groundwater flow direction. Stable isotopes ({sup 2}H and {sup 18}O) were used to identify and characterize the groundwater origin and mixing processes. Changes in the chemical composition of groundwater were shown to be mainly controlled by the groundwater and seawater mixing process, followed by cation exchange reactions and a Ca-Mg precipitation process due to the strong influence of the costal wetland. A gradual decreasing of the spatial and temporal saline intrusion was observed. (author)

Modeling irrigation behavior in groundwater systems

Science.gov (United States)

Foster, Timothy; Brozović, Nicholas; Butler, Adrian P.

2014-08-01

Integrated hydro-economic models have been widely applied to water management problems in regions of intensive groundwater-fed irrigation. However, policy interpretations may be limited as most existing models do not explicitly consider two important aspects of observed irrigation decision making, namely the limits on instantaneous irrigation rates imposed by well yield and the intraseasonal structure of irrigation planning. We develop a new modeling approach for determining irrigation demand that is based on observed farmer behavior and captures the impacts on production and water use of both well yield and climate. Through a case study of irrigated corn production in the Texas High Plains region of the United States we predict optimal irrigation strategies under variable levels of groundwater supply, and assess the limits of existing models for predicting land and groundwater use decisions by farmers. Our results show that irrigation behavior exhibits complex nonlinear responses to changes in groundwater availability. Declining well yields induce large reductions in the optimal size of irrigated area and irrigation use as constraints on instantaneous application rates limit the ability to maintain sufficient soil moisture to avoid negative impacts on crop yield. We demonstrate that this important behavioral response to limited groundwater availability is not captured by existing modeling approaches, which therefore may be unreliable predictors of irrigation demand, agricultural profitability, and resilience to climate change and aquifer depletion.

Forested wetland habitat

Science.gov (United States)

Duberstein, Jamie A.; Krauss, Ken W.; Kennish, Michael J.

2015-01-01

A forested wetland (swamp) is a forest where soils are saturated or flooded for at least a portion of the growing season, and vegetation, dominated by trees, is adapted to tolerate flooded conditions. A tidal freshwater forested wetland is a forested wetland that experiences frequent but short-term surface flooding via tidal action, with average salinity of soil porewater less than 0.5 g/l. It is known locally as tidal várzea in the Amazon delta, Brazil. A tidal saltwater forested wetland (mangrove forest) is a forested wetland that experiences frequent but short-term surface flooding via tidal action, with average salinity often exceeding 3 g/l and reaching levels that can exceed seawater. Mangrove ecosystems are composed of facultative halophytes that generally experience better growth at moderate salinity concentrations.

National Wetlands Inventory Lines

Data.gov (United States)

Minnesota Department of Natural Resources — Linear wetland features (including selected streams, ditches, and narrow wetland bodies) mapped as part of the National Wetlands Inventory (NWI). The National...

Freshwater Wetlands: A Citizen's Primer.

Science.gov (United States)

Catskill Center for Conservation and Development, Inc., Hobart, NY.

The purpose of this "primer" for the general public is to describe the general characteristics of wetlands and how wetland alteration adversely affects the well-being of humans. Particular emphasis is placed on wetlands in New York State and the northeast. Topics discussed include wetland values, destruction of wetlands, the costs of…

Wise use of wetlands: current state of protection and utilization of Chinese wetlands and recommendations for improvement.

Science.gov (United States)

Wang, Yanxia; Yao, Yong; Ju, Meiting

2008-06-01

Wetland protection and utilization sometimes appear to be in conflict, but promoting the wise use of wetlands can solve this problem. All countries face the challenge of sustainable development of wetlands to a greater or lesser extent, but the problem is especially urgent in developing countries, such as China, that want to accelerate their economic development without excessive environmental cost. Chinese wetlands contribute greatly to economic development, but improper use of these natural resources has endangered their existence. It is thus necessary to provide scientific guidance to managers and users of wetlands. In this paper, we analyze the present status of Chinese wetland protection and utilization, and discuss problems in six categories: a lack of public awareness of the need for wetland protection; insufficient funding for wetland protection and management; an imperfect legal system to protect wetlands; insufficient wetland research; lack of coordination among agencies and unclear responsibilities; and undeveloped technologies related to wetland use and protection. The wise use of Chinese wetlands will require improvements in four main areas: increased wetland utilization research, scientific management of wetland utilization, improved laws and regulations to protect wetlands, and wider dissemination of wetland knowledge. Based on these categories, we propose a framework for the optimization of wetland use by industry to provide guidance for China and other countries that cannot sacrifice economic benefits to protect their wetlands.

Pipeline corridors through wetlands

International Nuclear Information System (INIS)

Zimmerman, R.E.; Wilkey, P.L.; Isaacson, H.R.

1992-01-01

This paper presents preliminary findings from six vegetational surveys of gas pipeline rights-of-way (ROW) through wetlands and quantifies the impacts of a 20-year-old pipeline ROW through a boreal forest wetland. Six sites of various ages were surveyed in ecosystems ranging from coastal marsh to forested wetland. At all sites except one, both the number and the percentage of wetland species on the Row approximated or exceeded those in the adjacent natural area. The boreal forest study showed that (1) adjacent natural wetland areas were not altered in type; (2) water sheet flow restriction had been reversed by nature; (3) no nonnative plant species invaded the natural area; (4) three-quarters of the ROW area was a wetland, and (5) the ROW increased diversity

National Wetlands Inventory Polygons

Data.gov (United States)

Minnesota Department of Natural Resources — Wetland area features mapped as part of the National Wetlands Inventory (NWI). The National Wetlands Inventory is a national program sponsored by the US Fish and...

Characteristic community structure of Florida's subtropical wetlands: the Florida wetland condition index

Science.gov (United States)

Depending upon the classification scheme applied, there are between 10 and 45 different wetland types in Florida. Land use and land cover change has a marked effect on wetland condition, and different wetland types are affected differentially depending on many abiotic and biotic ...

Wetland Hydrology

Science.gov (United States)

This chapter discusses the state of the science in wetland hydrology by touching upon the major hydraulic and hydrologic processes in these complex ecosystems, their measurement/estimation techniques, and modeling methods. It starts with the definition of wetlands, their benefit...

Constructed wetlands : the Canadian context

Energy Technology Data Exchange (ETDEWEB)

Speer, S.; Champagne, P. [Queen' s Univ., Kingston, ON (Canada). Dept. of Civil Engineering

2006-07-01

Large volumes of wastewater from livestock and production facilities must be treated to minimize the contamination of waterways in agricultural areas. This paper investigated the use of constructed wetlands as a lower-cost and efficient method of treating agricultural wastewaters. The study found that while constructed wetlands required limited maintenance, temperature dependency of the constructed wetlands systems is a limiting factor in their widespread implementation. Lower operating temperatures are only overcome by constructing larger wetlands systems, which require a substantial amount of land. The Canadian climate poses significant challenges to the implementation of constructed wetlands, which become inoperative during winter months. Plants and bacteria normally become dormant or die during winter months, which can create a lag in wetland treatment during the initial months of operation in the Spring. Snowmelt and added rainfall in the Spring can also create a high flow within the wetland cells, as many constructed wetlands rely on runoff as a feed source. Washout of bacteria can occur. Wastewater storage systems or further engineering of the wetlands may be required. It was concluded that insulating wetland cells will maintain a warmer operating temperature, while the addition of an aeration system will increase the treatment efficiency of the wetland during winter months. 17 refs., 5 tabs., 2 figs.

National Wetlands Inventory Points

Data.gov (United States)

Minnesota Department of Natural Resources — Wetland point features (typically wetlands that are too small to be as area features at the data scale) mapped as part of the National Wetlands Inventory (NWI). The...

Comparative Hydrology, Water Quality, and Ecology of Selected Natural and Augmented Freshwater Wetlands in West-Central Florida

Science.gov (United States)

Lee, T.M.; Haag, K.H.; Metz, P.A.; Sacks, L.A.

2009-01-01

Comparing altered wetlands to natural wetlands in the same region improves the ability to interpret the gradual and cumulative effects of human development on freshwater wetlands. Hydrologic differences require explicit attention because they affect nearly all wetland functions and are an overriding influence on other comparisons involving wetland water quality and ecology. This study adopts several new approaches to quantify wetland hydrologic characteristics and then describes and compares the hydrology, water quality, and ecology of 10 isolated freshwater marsh and cypress wetlands in the mantled karst landscape of central Florida. Four of the wetlands are natural, and the other six have water levels indirectly lowered by ground-water withdrawals on municipally owned well fields. For several decades, the water levels in four of these altered wetlands have been raised by adding ground water in a mitigation process called augmentation. The two wetlands left unaugmented were impaired because their water levels were lowered. Multifaceted comparisons between the altered and natural wetlands are used to examine differences between marshes and cypress wetlands and to describe the effects of augmentation practices on the wetland ecosystems. In the karstic geologic setting, both natural and altered wetlands predominantly lost water to the surficial aquifer. Water leaking out of the wetlands created water-table mounds below the wetlands. The smallest mounds radiated only slightly beyond the vegetated area of the wetlands. The largest and steepest mounds occurred below two of the augmented wetlands. There, rapid leakage rates regenerated a largely absent surficial aquifer and mounds encompassed areas 7-8 times as large as the wetlands. Wetland leakage rates, estimated using a daily water-budget analysis applied over multiple years and normalized as inches per day, varied thirtyfold from the slowest leaking natural wetland to the fastest leaking augmented wetland. Leakage

Hydrogeologic framework, arsenic distribution, and groundwater geochemistry of the glacial-sediment aquifer at the Auburn Road landfill superfund site, Londonderry, New Hampshire

Science.gov (United States)

Degnan, James R.; Harte, Philip T.

2013-01-01

Leachate continues to be generated from landfills at the Auburn Road Landfill Superfund Site in Londonderry, New Hampshire. Impermeable caps on the three landfills at the site inhibit direct infiltration of precipitation; however, high water-table conditions allow groundwater to interact with landfill materials from below, creating leachate and ultimately reducing conditions in downgradient groundwater. Reducing conditions can facilitate arsenic transport by allowing it to stay in solution or by liberating arsenic adsorbed to surfaces and from geologic sources, such as glacial sediments and bedrock. The site occupies a 180-acre parcel of land containing streams, ponds, wetlands, and former gravel pits located in glacial sediment. Four areas, totaling 14 acres, including three landfills and one septage lagoon, were used for waste disposal. The site was closed in 1980 after volatile organic compounds associated with industrial waste dumping were detected. The site was added to the U.S. Environmental Protection Agency National Priority List in 1982, and the landfills were capped in 1996. Although volatile organic compound concentrations in groundwater have declined substantially, some measurable concentrations remain. Temporally variable and persistent elevated arsenic concentrations have been measured in groundwater affected by the landfill leachate. Microbial consumption of carbon found in leachate is a driver of reducing conditions that liberate arsenic at the site. In addition to sources of carbon in landfill leachate, wetland areas throughout the site also could contribute carbon to groundwater, but it is currently unknown if any of the wetland areas have downward or reversing gradients that could allow the infiltration of surface water to groundwater. Red-stained sediments and water indicate iron-rich groundwater discharge to surface water and are also associated with elevated concentrations of arsenic in sediment and groundwater. Ironrich groundwater seeps have

Degradation kinetics of chlorinated aliphatic hydrocarbons by methane oxidizers naturally-associated with wetland plant roots

Science.gov (United States)

Powell, C. L.; Goltz, M. N.; Agrawal, A.

2014-12-01

Chlorinated aliphatic hydrocarbons (CAHs) are common groundwater contaminants that can be removed from the environment by natural attenuation processes. CAH biodegradation can occur in wetland environments by reductive dechlorination as well as oxidation pathways. In particular, CAH oxidation may occur in vegetated wetlands, by microorganisms that are naturally associated with the roots of wetland plants. The main objective of this study was to evaluate the cometabolic degradation kinetics of the CAHs, cis-1,2-dichloroethene (cisDCE), trichloroethene (TCE), and 1,1,1-trichloroethane (1,1,1TCA), by methane-oxidizing bacteria associated with the roots of a typical wetland plant in soil-free system. Laboratory microcosms with washed live roots investigated aerobic, cometabolic degradation of CAHs by the root-associated methane-oxidizing bacteria at initial aqueous [CH4] ~ 1.9 mg L- 1, and initial aqueous [CAH] ~ 150 μg L- 1; cisDCE and TCE (in the presence of 1,1,1TCA) degraded significantly, with a removal efficiency of approximately 90% and 46%, respectively. 1,1,1TCA degradation was not observed in the presence of active methane oxidizers. The pseudo first-order degradation rate-constants of TCE and cisDCE were 0.12 ± 0.01 and 0.59 ± 0.07 d- 1, respectively, which are comparable to published values. However, their biomass-normalized degradation rate constants obtained in this study were significantly smaller than pure-culture studies, yet they were comparable to values reported for biofilm systems. The study suggests that CAH removal in wetland plant roots may be comparable to processes within biofilms. This has led us to speculate that the active biomass may be on the root surface as a biofilm. The cisDCE and TCE mass losses due to methane oxidizers in this study offer insight into the role of shallow, vegetated wetlands as an environmental sink for such xenobiotic compounds.

Flora characteristics of Chenier Wetland in Bohai Bay and biogeographic relations with adjacent wetlands

Science.gov (United States)

Zhao, Yanyun; Lu, Zhaohua; Liu, Jingtao; Hu, Shugang

2017-12-01

A key step towards the restoration of heavily disturbed fragile coastal wetland ecosystems is determining the composition and characteristics of the plant communities involved. This study determined and characterized the community of higher plants in the Chenier wetland of Bohai Bay using a combination of field surveys, quadrat approaches, and multivariate statistical analyses. This community was then compared to other adjacent wetlands (Tianjin, Qinhuangdao, Laizhouwan, Jiaozhouwan, and Yellow River Delta wetland) located near the Huanghai and Bohai Seas using principal coordinate analysis (PCoA). Results showed a total of 56 higher plant species belonging to 52 genera from 20 families in Chenier wetland, the majority of which were dicotyledons. Single-species families were predominant, while larger families, including Gramineae, Compositae, Leguminosae, and Chenopodiaceae contained a higher number of species (each⩾6 species). Cosmopolitan species were also dominant with apparent intrazonality. Abundance (number of species) of temperate species was twice that of tropical taxa. Species number of perennial herbs, such as Gramineae and Compositae, was generally higher. Plant diversity in the Chenier wetland, based on the Shannon-Wiener index, was observed to be between the Qinhuangdao and Laizhouwan indices, while no significant difference was found in other wetlands using the Simpson index. Despite these slight differences in diversity, PCoA based on species abundance and composition of the wetland flora suggest that the Bohai Chenier community was highly similar to the coastal wetlands in Tianjin and Laizhouwan, further suggesting that these two wetlands could be important breeding grounds and resources for the restoration of the plant ecosystem in the Chenier wetland.

Fringe wetlands

International Nuclear Information System (INIS)

Lugo, A.E.

1990-01-01

Fringe wetlands are characterized by the dominance of few species, a clear species zonation, synchrony of ecological processes with episodic events, and simplicity in the structure of vegetation. The structure and ecosystem dynamics of fringe forested wetlands are presented with emphasis on saltwater wetlands because they have been studied more than freshwater ones. The study areas were Caribbean and Florida mangroves. Fringe wetlands are found on the water edge of oceans, inland estuaries, and lakes. Water motion in the fringe is bi-directional and perpendicular to the forest and due mostly to tidal energy in oceanic and estuarine fringes. in lakes, water moves in and out of the fringe under the influence of wind, waves, or seiches. some fringe forests are occasionally flushed by terrestrial runoff or aquifer discharge. In contrast, fringe forests located on small offshore islands or steep coastal shroes are isolated from terrestrial runoff or aquifer discharge, and their hydroperiod is controlled by tides and waves only. Literature reviews suggest that ecosystem parameters such as vegetation structure, tree growth, primary productivity, and organic matter in sediments respond proportionally to hydrologic energy. Human activity that impacts on fringe forested wetlands include harvesting of trees, oil pollution and eutrophication. 72 refs., 12 figs., 9 tabs

Analysis of metolachlor ethane sulfonic acid (MESA) chirality in groundwater: A tool for dating groundwater movement in agricultural settings.

Science.gov (United States)

Rice, Clifford P; McCarty, Gregory W; Bialek-Kalinski, Krystyna; Zabetakis, Kara; Torrents, Alba; Hapeman, Cathleen J

2016-08-01

To better address how much groundwater contributes to the loadings of pollutants from agriculture we developed a specific dating tool for groundwater residence times. This tool is based on metolachlor ethane sulfonic acid, which is a major soil metabolite of metolachlor. The chiral forms of metolachlor ethane sulfonic acid (MESA) and the chiral forms of metolachlor were examined over a 6-year period in samples of groundwater and water from a groundwater-fed stream in a riparian buffer zone. This buffer zone bordered cropland receiving annual treatments with metolachlor. Racemic (rac) metolachlor was applied for two years in the neighboring field, and subsequently S-metolachlor was used which is enriched by 88% with the S-enantiomer. Chiral analyses of the samples showed an exponential increase in abundance of the S-enantiomeric forms for MESA as a function of time for both the first order riparian buffer stream (R(2)=0.80) and for groundwater within the riparian buffer (R(2)=0.96). However, the S-enrichment values for metolachlor were consistently high indicating different delivery mechanisms for MESA and metolachlor. A mean residence time of 3.8years was determined for depletion of the initially-applied rac-metolachlor. This approach could be useful in dating groundwater and determining the effectiveness of conservation measures. A mean residence time of 3.8years was calculated for groundwater feeding a first-order stream by plotting the timed-decay for the R-enantiomer of metolachlor ethane sulfonic acid. Published by Elsevier B.V.

Macroinvertebrate abundance, water chemistry, and wetland characteristics affect use of wetlands by avian species in Maine

Science.gov (United States)

Longcore, J.R.; McAuley, D.G.; Pendelton, G.W.; Bennatti, C.R.; Mingo, T.M.; Stromborg, K.L.

2006-01-01

Our objective was to determine use by avian species (e.g., piscivores, marsh birds, waterfowl, selected passerines) of 29 wetlands in areas with low (chemistry, basin characteristics, and avian use of different wetland types. Shallow, beaver (Castor canadensis)-created wetlands with the highest phosphorus levels and abundant and varied macrophyte assemblages supported greater densities of macroinvertebrates and numbers of duck broods (88.3% of all broods) in contrast to deep, glacial type wetlands with sparse vegetation and lower invertebrate densities that supported fewer broods (11.7%). Low pH may have affected some acid-intolerant invertebrate taxa (i.e., Ephemeroptera), but high mean numbers of Insecta per wetland were recorded from wetlands with a pH of 5.51. Other Classes and Orders of invertebrates were more abundant on wetlands with pH > 5.51. All years combined use of wetlands by broods was greater on wetlands with pH ≤ 5.51 (77.4%) in contract to wetlands with pH > 5.51 that supported 21.8% of the broods. High mean brood density was associated with mean number of Insecta per wetland. For lentic wetlands created by beaver, those habitats contained vegetative structure and nutrients necessary to provide cover to support invertebrate populations that are prey of omnivore and insectivore species. The fishless status of a few wetlands may have affected use by some waterfowl species and obligate piscivores.

Discovery and description of complete ammonium oxidizers in groundwater-fed rapid sand filters

DEFF Research Database (Denmark)

Palomo, Alejandro

as biological filtration has long been acknowledged and recently been investigated. Biological filtration technology is widely used around the world and is especially important in Denmark as groundwater is the main source water for drinking water production. Because the groundwater has a relative high-quality......, aeration followed by biological filtration is the only required treatment before distribution. In the last years, the microbial communities in rapid gravity sand filters, the typical biological filter used in Denmark, have been characterized, but little knowledge had been required about their physiological...... activity and roles in compound removal from the source water. This PhD project focused on a comprehensive investigation of the microbial communities in rapid sand filters beyond their purely taxonomical identification. For this purpose, samples collected from a rapid sand filter were subjected...

Coastal forests and groundwater: Using case studies to understand the effects of drivers and stressors for resource management

Science.gov (United States)

Timothy Callahan; Devendra Amatya; Peter Stone

2017-01-01

Forests are receiving more attention for the ecosystem goods and services they provide and the potential change agents that may affect forest health and productivity. Highlighting case examples from coastal forests in South Carolina, USA, we describe groundwater processes with respect to stressors and potential responses of a wetland-rich forested landscape,...

Variation in Assemblages of Small Fishes and Microcrustaceans After Inundation of Rarely Flooded Wetlands of the Lower Okavango Delta, Botswana

Science.gov (United States)

Siziba, Nqobizitha; Chimbari, Moses J.; Masundire, Hillary; Mosepele, Ketlhatlogile; Ramberg, Lars

2013-12-01

Water extraction from floodplain river systems may alter patterns of inundation of adjacent wetlands and lead to loss of aquatic biodiversity. Water reaching the Okavango Delta (Delta), Botswana, may decrease due to excessive water extraction and climate change. However, due to poor understanding of the link between inundation of wetlands and biological responses, it is difficult to assess the impacts of these future water developments on aquatic biota. Large floods from 2009 to 2011 inundated both rarely and frequently flooded wetlands in the Delta, creating an opportunity to examine the ecological significance of flooding of wetlands with widely differing hydrological characteristics. We studied the assemblages of small fishes and microcrustaceans, together with their trophic relationships, in temporary wetlands of the lower Delta. Densities of microcrustaceans in temporary wetlands were generally lower than previously recorded in these habitats. Microcrustacean density varied with wetland types and hydrological phase of inundation. High densities of microcrustaceans were recorded in the 2009 to 2010 flooding season after inundation of rarely flooded sites. Large numbers of small fishes were observed during this study. Community structure of small fishes differed significantly across the studied wetlands, with poeciliids predominant in frequently flooded wetlands and juvenile cichlids most abundant in rarely flooded wetlands (analysis of similarity, P < 0.05). Small fishes of <20 mm fed largely on microcrustaceans and may have led to low microcrustacean densities within the wetlands. This result matched our prediction that rarely flooded wetlands would be more productive; hence, they supported greater populations of microcrustaceans and cichlids, which are aggressive feeders. However, the predominance of microcrustaceans in the guts of small fishes (<20 mm) suggests that predation by fishes may also be an important regulatory mechanism of microcrustacean

Eco-hydrological process simulations within an integrated surface water-groundwater model

DEFF Research Database (Denmark)

Butts, Michael; Loinaz, Maria Christina; Bauer-Gottwein, Peter

2014-01-01

Integrated water resources management requires tools that can quantify changes in groundwater, surface water, water quality and ecosystem health, as a result of changes in catchment management. To address these requirements we have developed an integrated eco-hydrological modelling framework...... that allows hydrologists and ecologists to represent the complex and dynamic interactions occurring between surface water, ground water, water quality and freshwater ecosystems within a catchment. We demonstrate here the practical application of this tool to two case studies where the interaction of surface...... water and ground water are important for the ecosystem. In the first, simulations are performed to understand the importance of surface water-groundwater interactions for a restored riparian wetland on the Odense River in Denmark as part of a larger investigation of water quality and nitrate retention...

Wetlands & Deepwater Habitats - MO 2012 East West Gateway Wetlands (SHP)

Data.gov (United States)

NSGIC State | GIS Inventory — Cowardin’s Classification of Wetlands and Deep Water Habitats of the United States (http://www.npwrc.usgs.gov/resource/wetlands/classwet/index.htm), together with...

Complementary effects of surface water and groundwater on soil moisture dynamics in a degraded coastal floodplain forest

Science.gov (United States)

Kaplan, D.; Muñoz-Carpena, R.

2011-02-01

SummaryRestoration of degraded floodplain forests requires a robust understanding of surface water, groundwater, and vadose zone hydrology. Soil moisture is of particular importance for seed germination and seedling survival, but is difficult to monitor and often overlooked in wetland restoration studies. This research hypothesizes that the complex effects of surface water and shallow groundwater on the soil moisture dynamics of floodplain wetlands are spatially complementary. To test this hypothesis, 31 long-term (4-year) hydrological time series were collected in the floodplain of the Loxahatchee River (Florida, USA), where watershed modifications have led to reduced freshwater flow, altered hydroperiod and salinity, and a degraded ecosystem. Dynamic factor analysis (DFA), a time series dimension reduction technique, was applied to model temporal and spatial variation in 12 soil moisture time series as linear combinations of common trends (representing shared, but unexplained, variability) and explanatory variables (selected from 19 additional candidate hydrological time series). The resulting dynamic factor models yielded good predictions of observed soil moisture series (overall coefficient of efficiency = 0.90) by identifying surface water elevation, groundwater elevation, and net recharge (cumulative rainfall-cumulative evapotranspiration) as important explanatory variables. Strong and complementary linear relationships were found between floodplain elevation and surface water effects (slope = 0.72, R2 = 0.86, p < 0.001), and between elevation and groundwater effects (slope = -0.71, R2 = 0.71, p = 0.001), while the effect of net recharge was homogenous across the experimental transect (slope = 0.03, R2 = 0.05, p = 0.242). This study provides a quantitative insight into the spatial structure of groundwater and surface water effects on soil moisture that will be useful for refining monitoring plans and developing ecosystem restoration and management scenarios

Wetlands Research Program. Wetland Evaluation Technique (WET). Volume 2. Methodology.

Science.gov (United States)

1987-10-01

to waves taller than I ft? • " Guidelines: 1 "Sufficient" is defined as the height of vegetation or relief multiplied * by length of vegetation or...Sci., Interim Rep. No. 3, Gloucester Point, VA. 52 pp. 203 VI. 4 WET 2.0 Simmons, E. G. 1957. An ecological survey of the Upper Laguna Madre of Texas...A wetland class characterized by vegetation that is 6 m or taller . Fringe Wetland - Fringe wetlands along a channel (i.e.. river, stream, etc.)are

Chromium in surface water and groundwater in the surrounding area of a tannery: relationships with water quality baseline, Elena, Cordoba. Argentina

International Nuclear Information System (INIS)

Matteoda, E.; Blarasin, M.; Damilano, G.; Cabrera, A.; Giuliano Albo, J.

2009-01-01

The basin of the El Barreal stream is a dominantly rural area in which groundwater is used for all activities whereas the stream is used as sink of residues and effluents. The existence of a tannery, which discharge the effluents into a wetland (which is drained by the stream), reveals the need to study the presence of Chromium in surface and groundwater and to compare values derived from pollution with those corresponding to the natural water baseline values. Fifty three samples of surface and groundwater were abstracted and chemical analyses were made, including total Chromium in water and plants. The chemical analysis results were studied by means of conventional and statistical techniques. The local and regional geological characteristics allow us to interpret that Chromium in water is derived from source minerals, being possible to stand out that high values probably are related to nearby serpentinite bodies.The values of total chrome in surface and groundwater are included in the natural quality baseline range calculated for this basin (0,25-5ug/L), exempting those samples with higher values linked to sites with farming activities and to the wetland environment where the Chromium effluent is discharged. In the last place, Chromium was retained in soil and plants whereas the aquifer was affected by a contaminant plume of total dissolved solids because of advective-dispersive transport. In the 2009 monitoring survey, a small increase of Chromium in groundwater was detected in relation to that of 2005, being assumed that partial desorption of Chromium is taking place from the solid phase. (Author) 19 refs.

The Multimedia Environmental Pollutant Assessment System (MEPAS reg-sign): Completely-Stirred Tank Reactor (CSTR) formulations for the wetland pathway

International Nuclear Information System (INIS)

McDonald, J.P.; van der Aa, N.G.F.M.; Whelan, G.

1997-06-01

The Multimedia Environmental Pollutant Assessment System (MEPAS) is a physics-based environmental analysis code integrating source-term, fate, and exposure models for concentration, dose, or risk endpoints. Developed by Pacific Northwest National Laboratory for the US Department of Energy, MEPAS is designed for site-specific assessments using readily available information. Endpoints are computed for chemical and radioactive pollutants. For human health impacts, risks are computed for radioactive and hazardous carcinogens, and hazard quotients for noncarcinogens. This system has wide applicability to environmental problems using air, groundwater, surface-water, overland, wetland, and exposure models. MEPAS enables users to simulate release of contaminants from a source; transport of contaminants through the air, groundwater, surface-water, overland, or wetland pathways; and transfer of contaminants through food chains and exposure pathways to the exposed individual or population. Whenever available and appropriate, guidance and/or models from the US Environmental Protection Agency, International Commission on Radiological Protection, and National Council on Radiation Protection and Measurements were used to facilitate compatibility and acceptance. Although based on relatively standard transport and exposure computation approaches, MEPAS uniquely integrated these approaches into a single system, providing a consistent basis for evaluating health impacts for a large number of problems and sites. Implemented on a desktop computer, a user-friendly platform allows the user to define the problem, input the required data, and execute the appropriate models. This document describes the mathematical formulations for the Completely-Stirred Tank Reactor (CSTR) component of MEPAS as applied to the wetland pathway

Kansas Playa Wetlands

Data.gov (United States)

Kansas Data Access and Support Center — This digital dataset provides information about the distribution, areal extent, and morphometry of playa wetlands throughout western Kansas. Playa wetlands were...

[Research progress on wetland ecotourism].

Science.gov (United States)

Wang, Li-Long; Lu, Lin

2009-06-01

Wetland is rich in biodiversity and cultural diversity, possessing higher tourism value and environmental education and community participation functions. Wetland ecotourism reflects the sustainable development of tourism economy and wetland protection, having received great concern from governments and scholars at home and abroad. This paper summarized the related theories and practices, discussed the research advances in wetland ecotourism from the aspects of significance, progress, contents, methods and results, and pointed out the important research fields in the future, aimed to accelerate the development of wetland ecotourism research and to provide reference about the resources exploitation, environment protection, and scientific administration of wetland and related scenic areas.

Design of Infiltration Well in Wetlands Area that Suitable for Giving Maximum Groundwater Recharge

Directory of Open Access Journals (Sweden)

Irfan Prasetia

2016-02-01

Full Text Available Growth in residential, industrial, and office  area,are significantly occurred in all city in Indonesia. Unfortunately, this is also caused more land that being covered by pavement and concrete in the cities. Realized or not it will disturb the availability of the groundwater and also lead to flooding in the rainy season. One of the effective solutions to solve this problem is by making sufficient numbers of infiltration well in the city, especially in the residential area. This research was conducted to analyze the ideal design of the infiltration well in the residential area. The design was made according to the equation by Sunjoto, which also refers to Indonesia standard (SNI No: 03- 2453-2002. The results show that the ideal dimension for the infiltration well is to use the radius of the well (R of 1.25 m. With the R of 1.25 will give a significant recharge to the groundwater as much as ≈ 2.400 liter. It is expected that this research encourage a development in the urban drainage systems which will consider the environment and the groundwater reservation for the balance of our ecosystem.

Biotic development comparisons of a wetland constructed to treat mine water drainage with a natural wetland system

International Nuclear Information System (INIS)

Webster, H.J.; Hummer, J.W.; Lacki, M.J.

1994-01-01

Using 5-yr of baseline data from a constructed wetland, the authors compared the biotic changes in this wetland to conditions in a natural wetland to determine if biotic development patterns were similar. The constructed wetland was built in 1985 to treat a coal mine discharge and was planted with broadleaf cattail (Typha latifolia) within the three-cell, 0.26 ha wetland. Species richness in permanent quadrants of the constructed wetland declined over the study period, while cattail coverage increased. Plant species composition diversified at the edges, with several species becoming established. The constructed wetland deepened and expanded slightly in area coverage during the study period. The constructed wetland supported herptofaunal communities that appeared more stable through time than those of the natural wetland and sustained a rudimentary food chain dependent upon autotrophic algal populations. Despite fundamental differences in substrate base, morphology, and water flow patterns, biotic trends for the constructed wetland coincided with succession-like patterns at the natural wetland. They suggest that further shifts in the biotic composition of the constructed wetland are likely, but the system should continue to persist if primary production meets or exceeds the microbial metabolic requirements necessary to treat mine drainage

Groundwater Flow Model of Göksu Delta Coastal Aquifer System

Science.gov (United States)

Erdem Dokuz, Uǧur; Çelik, Mehmet; Arslan, Şebnem; Engin, Hilal

2016-04-01

Like many other coastal areas, Göksu Delta (Mersin-Silifke, Southern Turkey) is a preferred place for human settlement especially due to its productive farmlands and water resources. The water dependent ecosystem in Göksu delta hosts about 332 different plant species and 328 different bird species besides serving for human use. Göksu Delta has been declared as Special Environmental Protection Zone, Wildlife Protection Area, and RAMSAR Convention for Wetlands of International Importance area. Unfortunately, rising population, agricultural and industrial activities cause degradation of water resources both by means of quality and quantity. This problem also exists for other wetlands around the world. It is necessary to prepare water management plans by taking global warming issues into account to protect water resources for next generations. To achieve this, the most efficient tool is to come up with groundwater management strategies by constructing groundwater flow models. By this aim, groundwater modeling studies were carried out for Göksu Delta coastal aquifer system. As a first and most important step in all groundwater modeling studies, geological and hydrogeological settings of the study area have been investigated. Göksu Delta, like many other deltaic environments, has a complex structure because it was formed with the sediments transported by Göksu River throughout the Quaternary period and shaped throughout the transgression-regression periods. Both due to this complex structure and the lack of observation wells penetrating deep enough to give an idea of the total thickness of the delta, it was impossible to reveal out the hydrogeological setting in a correct manner. Therefore, six wells were drilled to construct the conceptual hydrogeological model of Göksu Delta coastal aquifer system. On the basis of drilling studies and slug tests that were conducted along Göksu Delta, hydrostratigraphic units of the delta system have been obtained. According to

Urban "accidental" wetlands mediate water quality and heat exposure for homeless populations in a desert city

Science.gov (United States)

Palta, M.

2015-12-01

In urban settings where humans interact in complex ways with ecosystems, there may be hidden or unanticipated benefits (services) or harm (disservices) conferred by the built environment. We examined interactions of a highly vulnerable population, the homeless, with urban waterways and wetlands in the desert city of Phoenix, Arizona, U.S.A. Climate change models project increases in heat, droughts, and extreme floods for the southwestern U.S. These projected changes pose a number of problems for sustainability and quality of future water supply, and the ability of human populations to mitigate heat stress and avoid fatalities. Urban wetlands that are created "accidentally" (by water pooling in abandoned areas of the landscape) have many structural (e.g., soils and hydrology) and functional (e.g., high denitrification) elements that mimic natural, unaltered aquatic systems. Accidental wetland systems in the dry bed of the Salt River, fed by storm and waste water from urban Phoenix, are located within economically depressed sections of the city, and show the potential for pollutant and heat mitigation. We used a mixed-method socio-ecological approach to examine wetland ecosystem functions and the ways in which homeless populations utilize Salt River wetlands for ecosystem services. Interviews and trash surveys indicated that homeless people are accessing and utilizing the wetlands as a source of running water, for sanitary and heat mitigation services, and for recreation and habitation. Environmental monitoring demonstrated that the wetlands can provide a reliable source of running water, nutrient and pathogen removal, heat mitigation, and privacy, but they may also pose a health risk to individuals coming in contact with the water through drinking or bathing. Whether wetlands provided a net benefit vs. harm varied according to site, season, and particular service, and several tradeoffs were identified. For example, heat is highest during the summer storm season

Paleoenvironmental and paleohydrochemical conditions of dolomite formation within a saline wetland in arid northwest Australia

Science.gov (United States)

Mather, Caroline C.; Skrzypek, Grzegorz; Dogramaci, Shawan; Grierson, Pauline F.

2018-04-01

Groundwater dolocrete occurring within the Fortescue Marsh, a large inland wetland in the Pilbara region of northwest Australia, has been investigated to provide paleoenvironmental and paleohydrological records and further the understanding of low temperature dolomite formation in terrestrial settings over the Quaternary Period. Two major phases of groundwater dolocrete formation are apparent from the presence of two distinct units of dolocrete, based on differences in depth, δ18O values and mineral composition. Group 1 (G1) occurs at depth 20-65 m b.g.l. (below ground level) and contains stoichiometric dolomite with δ18O values of -4.02-0.71‰. Group 2 (G2) is shallower (0-23 m b.g.l.), occurring close to the current groundwater level, and contains Ca-rich dolomite ± secondary calcite with a comparatively lower range of δ18O values (-7.74 and -6.03‰). Modelled δ18O values of paleogroundwater from which older G1 dolomite precipitated indicated highly saline source water, which had similar stable oxygen isotope compositions to relatively old brine groundwater within the Marsh, developed under a different hydroclimatic regime. The higher δ18O values suggest highly evaporitic conditions occurred at the Marsh, which may have been a playa lake to saline mud flat environment. In contrast, G2 dolomite precipitated from comparatively fresher water, and modelled δ18O values suggested formation from mixing between inflowing fresher groundwater with saline-brine groundwater within the Marsh. The δ18O values of the calcite indicates formation from brackish to saline groundwater, which suggests this process may be associated with coeval gypsum dissolution. In contrast to the modern hydrology of the Marsh, which is surface water dependent and driven by a flood and drought regime, past conditions conducive to dolomite precipitation suggest a groundwater dependent system, where shallow groundwaters were influenced by intensive evaporation.

Geochemistry and hydrology of a calcareous fen within the Savage Fen wetlands complex, Minnesota, USA

Science.gov (United States)

Komor, S.C.

1994-01-01

Savage Fen is a wetlands complex at the base of north-facing bluffs in the Minnesota River Valley. The complex includes 27.8 hectares of calcareous fen that host rare calciphile plants whose populations are declining in Minnesota. Water and sediment compositions in the calcareous fen were studied to gain a better understanding of the hydrologie System that sustains the rare vegetation. Groundwater in the fen is a calcium-magnesium-bicarbonate type with circumneutral pH values. The groundwater composition is the resuit of interactions among water, dissolved and gaseous carbon species, carbonates, and ion exchangers. Shallow groundwater is distinguished from deep groundwater by smaller concentrations of chloride, sulfate, magnesium, and sodium, and larger concentrations of calcium, bicarbonate, hydrogen sulfide, and ammonium. Magnesian calcite is the prevalent carbonate in unconsolidated sedimentary fill beneath the fen and is an important source and sink for dissolved calcium, magnesium, and inorganic carbon. Calcite concentrations just below the water table are small because aerobic and anaerobic oxidation of organic matter increase the partial pressure of carbon dioxide (PCO2), decrease pH, and cause calcite to dissolve. Thick calcite accumulations just above the water table, in the root zone of calciphile plants, result from water table fluctuations and attendant changes in PCO2. Groundwater beneath Savage Fen recharges in lakes and ponds south of the fen and upwells to the surface within the fen. Water at the water table is a mixture of upwelling groundwater and water near the surface that flows downslope from higher elevations in the fen. Changes in oxygen and hydrogen isotope compositions of shallow groundwater indicate that the proportion of upwelling groundwater in shallow groundwater decreases downgradient in the calcareous fen. Encroachment of reed grasses into the calcareous fen may reflect human-caused disturbances in the recharge area.

Fate of high loads of ammonia in a pond and wetland downstream from a hazardous waste disposal site.

Science.gov (United States)

Cutrofello, Michele; Durant, John L

2007-07-01

Halls Brook (eastern Massachusetts, USA) is a significant source of total dissolved ammonia (sum of NH(3) and NH(4)(+); (NH(3))(T)) to the Aberjona River, a water body listed for NH(3) impairment on the Clean Water Act section 303(d) list. We hypothesized (1) that (NH(3))(T) in Halls Brook derived from a hazardous waste site via groundwater discharging to a two-basin pond that feeds the brook; and (2) that transport of (NH(3))(T) to the Aberjona River was controlled by lacustrine and wetland processes. To test these hypotheses we measured (NH(3))(T) levels in the brook, the pond, and a wetlands directly downstream of the pond during both dry and wet weather over a ten month period. In addition, we analyzed sediment cores and nitrogen isotopes, and performed mass balance calculations. Groundwater discharge from beneath the hazardous waste site was the major source of (NH(3))(T) (20-67 kg d(-1)) and salinity to the north basin of the pond. The salty bottom waters of the north basin were anoxic on all sampling dates, and exhibited relatively stable (NH(3))(T) concentrations between 200 and 600 mg Nl(-1). These levels were >100-times higher than typical background levels, and 8-24-times above the acute effects level for (NH(3))(T) toxicity. Bottom waters from the north basin continuously spill over into the south basin contributing approximately 50% of the (NH(3))(T) load entering this basin. The remainder comes from Halls Brook, which receives (NH(3))(T) loadings from as yet unknown sources upstream. During storm events up to 50% of the mass of (NH(3))(T) was flushed from the south basin and into the wetlands. The wetlands acted as a (NH(3))(T) sink in dry weather in the growing season and a discharge-dependent (NH(3))(T) source to the Aberjona River during rainstorms.

Percent Wetland Cover

Data.gov (United States)

U.S. Environmental Protection Agency — Wetlands act as filters, removing or diminishing the amount of pollutants that enter surface water. Higher values for percent of wetland cover (WETLNDSPCT) may be...

Water Follies: Groundwater Pumping and the Fate of America's Fresh Waters

Science.gov (United States)

Glennon, R.

2002-12-01

The next time you open a bottle of spring water, consider that it may have come from a well that is drying up a blue-ribbon trout stream. The next time you super-size a meal at McDonald's, note that the fries are all the same length. That's because the potato farmers irrigate their fields with groundwater from wells, some adjacent to nearby rivers. The next time you purchase gold jewelry, consider that it may have come from a mine that has pumped so much groundwater to de-water the gold-bearing rock that 60 to100 years will pass before the water table recovers. The next time you water your suburban lawn, pause to reflect on what that's doing to the nearby wetland. And the next time you visit Las Vegas and flip on the light in your hotel room, consider that the electricity may have been generated by a coal-fired power plant supplied by a slurry pipeline that uses groundwater critical to springs sacred to the Hopi people. These and countless other seemingly innocuous activities reflect our individual and societal dependence on groundwater that is hydrologically connected to surface water. Hydrologists understand that ground and surface water are interconnected, but frequently the legal rules governing water distinguish between ground and surface water. This has led to groundwater pumping that has dried up many rivers, particularly in the arid West. In Arizona, many once verdant streams have become desiccated sandboxes as city, mines, and farms pumped groundwater to such an extent that surface flows were totally depleted. The problem of the impact of groundwater pumping on the environment, however, is not confined to the arid West. It is an enormous national, indeed international problem. This presentation will focus on the United States and illustrate with examples from around the country the array of environmental problems caused by excessive groundwater pumping. The locations of these case studies range from Maine to California, from Minnesota to Florida, and from

Preliminary evaluation of a constructed wetland for treating extremely alkaline (pH 12) steel slag drainage.

Science.gov (United States)

Mayes, W M; Aumônier, J; Jarvis, A P

2009-01-01

High pH (> 12) leachates are an environmental problem associated with drainage from lime (CaO)-rich industrial residues such as steel slags, lime spoil and coal combustion residues. Recent research has highlighted the potential for natural ('volunteer') wetlands to buffer extremely alkaline influent waters. This appears ascribable to high CO(2) partial pressures in the wetland waters from microbial respiration, which accelerates precipitation of calcium carbonate (CaCO(3)), and the high specific surface area for mineral precipitation offered by macrophytes. The research presented here builds on this and provides preliminary evaluation of a constructed wetland built in March 2008 to buffer drainage from steel slag heaps in north-east England. The drainage water from the slag mounds is characterised by a mean pH of 11.9, high concentrations of Ca (up to 700 mg/L), total alkalinity (up to 800 mg/L as CaCO(3)) and are slightly brackish (Na = 300 mg/L; Cl = 400 mg/L) reflecting native groundwaters at this coastal setting. Documented calcite precipitation rates (mean of 5 g CaCO(3)/m(2)/day) from nearby volunteer sites receiving steel slag drainage were used to scale the constructed wetland planted with Phragmites australis; a species found to spontaneously grow in the vicinity of the discharge. Improved performance of the wetland during summer months may at least in part be due to biological activity which enhances rates of calcite precipitation and thus lowering of pH. Secondary Ca-rich precipitates also serve as a sink for some trace elements present at low concentrations in the slag leachate such as Ni and V. The implications for scaling and applying constructed wetlands for highly alkaline drainage are discussed.

Environmental Behavior and Fate of Explosives in Groundwater from the Milan Army Ammunition Plant in Aquatic and Wetland Plants. Fate of TNT and RDX

National Research Council Canada - National Science Library

Best, Elly

1998-01-01

The present study was performed to elucidate the environmental behavior and fate of TNT and RDX in aquatic and wetland plants collected from a field-scale wetland demonstration deployed at Milan Army...

Modelling groundwater discharge areas using only digital elevation models as input data

International Nuclear Information System (INIS)

Brydsten, Lars

2006-10-01

Advanced geohydrological models require data on topography, soil distribution in three dimensions, vegetation, land use, bedrock fracture zones. To model present geohydrological conditions, these factors can be gathered with different techniques. If a future geohydrological condition is modelled in an area with positive shore displacement (say 5,000 or 10,000 years), some of these factors can be difficult to measure. This could include the development of wetlands and the filling of lakes. If the goal of the model is to predict distribution of groundwater recharge and discharge areas in the landscape, the most important factor is topography. The question is how much can topography alone explain the distribution of geohydrological objects in the landscape. A simplified description of the distribution of geohydrological objects in the landscape is that groundwater recharge areas occur at local elevation curvatures and discharge occurs in lakes, brooks, and low situated slopes. Areas in-between these make up discharge areas during wet periods and recharge areas during dry periods. A model that could predict this pattern only using topography data needs to be able to predict high ridges and future lakes and brooks. This study uses GIS software with four different functions using digital elevation models as input data, geomorphometrical parameters to predict landscape ridges, basin fill for predicting lakes, flow accumulations for predicting future waterways, and topographical wetness indexes for dividing in-between areas based on degree of wetness. An area between the village of and Forsmarks' Nuclear Power Plant has been used to calibrate the model. The area is within the SKB 10-metre Elevation Model (DEM) and has a high-resolution orienteering map for wetlands. Wetlands are assumed to be groundwater discharge areas. Five hundred points were randomly distributed across the wetlands. These are potential discharge points. Model parameters were chosen with the

Modeling the Effects of Sea-Level Rise on Groundwater Levels in Coastal New Hampshire

Science.gov (United States)

Jacobs, J. M.; Knott, J. F.; Daniel, J.; Kirshen, P. H.

2017-12-01

Coastal communities with high population density and low topography are vulnerable from sea-level rise (SLR) caused by climate change. Groundwater in coastal communities will rise with sea level impacting water quality, the structural integrity of infrastructure, and natural ecosystem health. SLR-induced groundwater rise has been studied in areas of high aquifer transmissivity and in low-lying areas immediately along the coast. In this regional study, we investigate SLR-induced groundwater rise in a coastal area characterized by shallow unconsolidated deposits overlying fractured bedrock, typical of the glaciated northeast United States. MODFLOW, a numerical groundwater-flow model, is used with groundwater observations, lidar topography, surface-water hydrology, and groundwater withdrawals to investigate SLR-induced changes in groundwater levels and vadose-zone thickness in New Hampshire's Seacoast. The SLR groundwater signal is detected up to 5 km from the coast, more than 3 times farther inland than projected surface-water flooding associated with SLR. Relative groundwater rise ranges from 38 to 98% of SLR within 1 km of the shoreline and drops below 4% between 4 and 5 km from the coast. The largest magnitude of SLR-induced groundwater rise occurs in the marine and estuarine deposits and land areas with tidal water bodies on three sides. In contrast, groundwater rise is dampened near streams. Groundwater inundation caused by 2 m of SLR is projected to contribute 48% of the total land inundation area in the City of Portsmouth with consequences for built and natural resources. Freshwater wetlands are projected to expand 3% by year 2030 increasing to 25% by year 2100 coupled with water-depth increases. These results imply that underground infrastructure and natural resources in coastal communities will be impacted by rising groundwater much farther inland than previously thought when considering only surface-water flooding from SLR.

Fresh meteoric versus recirculated saline groundwater nutrient inputs into a subtropical estuary

International Nuclear Information System (INIS)

Sadat-Noori, Mahmood; Santos, Isaac R.; Tait, Douglas R.; Maher, Damien T.

2016-01-01

The role of groundwater in transporting nutrients to coastal aquatic systems has recently received considerable attention. However, the relative importance of fresh versus saline groundwater-derived nutrient inputs to estuaries and how these groundwater pathways may alter surface water N:P ratios remains poorly constrained. We performed detailed time series measurements of nutrients in a tidal estuary (Hat Head, NSW, Australia) and used radium to quantify the contribution of fresh and saline groundwater to total surface water estuarine exports under contrasting hydrological conditions (wet and dry season). Tidally integrated nutrient fluxes showed that the estuary was a source of nutrients to the coastal waters. Dissolved inorganic nitrogen (DIN) export was 7-fold higher than the average global areal flux rate for rivers likely due to the small catchment size, surrounding wetlands and high groundwater inputs. Fresh groundwater discharge was dominant in the wet season accounting for up to 45% of total dissolved nitrogen (TDN) and 48% of total dissolved phosphorus (TDP) estuarine exports. In the dry season, fresh and saline groundwater accounted for 21 and 33% of TDN export, respectively. The combined fresh and saline groundwater fluxes of NO_3, PO_4, NH_4, DON, DOP, TDN and TDP were estimated to account for 66, 58, 55, 31, 21, 53 and 47% of surface water exports, respectively. Groundwater-derived nitrogen inputs to the estuary were responsible for a change in the surface water N:P ratio from typical N-limiting conditions to P-limiting as predicted by previous studies. This shows the importance of both fresh and saline groundwater as a source of nutrients for coastal productivity and nutrient budgets of coastal waters. - Highlights: • Groundwater TDN and TDP fluxes account for 53 and 47% of surface water exports. • The estuary DIN export was 7-fold higher than the average global areal flux. • Fresh GW nutrient input dominated the wet season and saline GW the

Carbon dynamics in wetland restoration

Energy Technology Data Exchange (ETDEWEB)

Kovalenko, K.; Ciborowski, J.; Gardner-Costa, J.; Slama, C. [Windsor Univ., ON (Canada); Daly, C.; Hornung, J. [Suncor Energy, Calgary, AB (Canada); Dixon, G.; Farwell, A. [Waterloo Univ., ON (Canada); Foote, L.; Frederick, K.; Roy, M. [Alberta Univ., Edmonton, AB (Canada); Liber, K. [Saskatchewan Univ., Saskatoon, SK (Canada); Smits, J. [Calgary Univ., AB (Canada); Wytrykush, C. [Syncrude Canada Ltd., Edmonton, AB (Canada)

2010-07-01

This study focused on the reclamation of wetland ecosystems impacted by oil sands development in the boreal wetlands. Although these wetlands play an important role in global carbon balance, their ecosystem function is compromised by direct and regional anthropogenic disturbance and climate change. Large oil sand mining areas that require reclamation generate substantial quantities of extraction process-affected materials. In order to determine if the reclaimed wetlands were restored to equivalent ecosystem function, this study evaluated carbon flows and food web structure in oil sands-affected wetlands. The purpose was to determine whether a prescribed reclamation strategy or topsoil amendment accelerates reclaimed wetland development to produce self-sustaining peatlands. In addition to determining carbon fluxes, this study measured compartment standing stocks for residual hydrocarbons, organic substrate, bacterioplankton, phytoplankton, biofilm, macrophytes, detritus, zoobenthos and aquatic-terrestrial exports. Most biotic 28 compartments differed between oil-sands-affected and reference wetlands, but the difference lessened with age. Macroinvertebrate trophic diversity was lower in oil sands-affected wetlands. Peat amendment seemed to speed convergence for some compartments but not others. These results were discussed in the context of restoration of ecosystem function and optimization of reclamation strategies.

Changes in the Regional Groundwater Aquifer and Potential Impacts on Surface Waters in Central Zealand, Denmark

DEFF Research Database (Denmark)

Thorn, Paul

The regional, confined aquifer on the island of Zealand, in eastern Denmark, is the primary aquifer used for large-scale abstraction for the supplies of all larger cities, including Roskilde and the greater Copenhagen metropolitan area. Large-scale groundwater abstraction from this aquifer...... in the area near Lejre Denmark (approximately 15km to the SW of Roskilde) began in 1937, exporting approximately 18 million m3 of water per year to supply the city of Copenhagen. After abstraction began, streams in the area were observed to go dry after extended periods without precipitation, where......, wetlands and lakes in the area. The results show that there was a significant impact on the regional groundwater aquifer in the Langvad river catchment, with groundwater as much as 17m lower in 1987 from 1936 (pre-abstraction). However, in the Elverdam river catchment, the levels remained virtually...

Morphology of a Wetland Stream

Science.gov (United States)

Jurmu; Andrle

1997-11-01

/ Little attention has been paid to wetland stream morphology in the geomorphological and environmental literature, and in the recently expanding wetland reconstruction field, stream design has been based primarily on stream morphologies typical of nonwetland alluvial environments. Field investigation of a wetland reach of Roaring Brook, Stafford, Connecticut, USA, revealed several significant differences between the morphology of this stream and the typical morphology of nonwetland alluvial streams. Six morphological features of the study reach were examined: bankfull flow, meanders, pools and riffles, thalweg location, straight reaches, and cross-sectional shape. It was found that bankfull flow definitions originating from streams in nonwetland environments did not apply. Unusual features observed in the wetland reach include tight bends and a large axial wavelength to width ratio. A lengthy straight reach exists that exceeds what is typically found in nonwetland alluvial streams. The lack of convex bank point bars in the bends, a greater channel width at riffle locations, an unusual thalweg location, and small form ratios (a deep and narrow channel) were also differences identified. Further study is needed on wetland streams of various regions to determine if differences in morphology between alluvial and wetland environments can be applied in order to improve future designs of wetland channels.KEY WORDS: Stream morphology; Wetland restoration; Wetland creation; Bankfull; Pools and riffles; Meanders; Thalweg

Michigan Wetlands: Yours To Protect. A Citizen's Guide to Local Involvement in Wetland Protection. Second Edition.

Science.gov (United States)

Cwikiel, Wilfred

This guidebook is designed to assist concerned Michigan citizens, local governments, conservation organizations, landowners, and others in their efforts to initiate wetlands protection activities. Chapter 1 focuses on wetland functions, values, losses, and the urgent need to protect wetland resources. Chapter 2 discusses wetland identification and…

40 CFR 258.12 - Wetlands.

Science.gov (United States)

2010-07-01

... degraded wetlands or creation of man-made wetlands); and (5) Sufficient information is available to make a... expansions shall not be located in wetlands, unless the owner or operator can make the following...

Holes in the Bathtub: Water Table Dependent Services and Threshold Behavior in an Economic Model of Groundwater Extraction

Science.gov (United States)

Kirk-lawlor, N. E.; Edwards, E. C.

2012-12-01

In many groundwater systems, the height of the water table must be above certain thresholds for some types of surface flow to exist. Examples of flows that depend on water table elevation include groundwater baseflow to river systems, groundwater flow to wetland systems, and flow to springs. Meeting many of the goals of sustainable water resource management requires maintaining these flows at certain rates. Water resource management decisions invariably involve weighing tradeoffs between different possible usage regimes and the economic consequences of potential management choices are an important factor in these tradeoffs. Policies based on sustainability may have a social cost from forgoing present income. This loss of income may be worth bearing, but should be well understood and carefully considered. Traditionally, the economic theory of groundwater exploitation has relied on the assumption of a single-cell or "bathtub" aquifer model, which offers a simple means to examine complex interactions between water user and hydrologic system behavior. However, such a model assumes a closed system and does not allow for the simulation of groundwater outflows that depend on water table elevation (e.g. baseflow, springs, wetlands), even though those outflows have value. We modify the traditional single-cell aquifer model by allowing for outflows when the water table is above certain threshold elevations. These thresholds behave similarly to holes in a bathtub, where the outflow is a positive function of the height of the water table above the threshold and the outflow is lost when the water table drops below the threshold. We find important economic consequences to this representation of the groundwater system. The economic value of services provided by threshold-dependent outflows (including non-market value), such as ecosystem services, can be incorporated. The value of services provided by these flows may warrant maintaining the water table at higher levels than would

Evaluation of a market in wetland credits: entrepreneurial wetland banking in Chicago.

Science.gov (United States)

Robertson, Morgan; Hayden, Nicholas

2008-06-01

With the rise of market-led approaches to environmental policy, compensation for permitted discharge of dredge or fill material into wetlands under Section 404 of the U.S. Clean Water Act has been purchased increasingly from entrepreneurial third-party providers. The growth of this practice (i.e., entrepreneurial wetland banking) has resolved many challenges associated with wetland compensation. But it has also produced (1) quantifiable temporal loss of wetland ecological functions, (2) spatial redistribution of wetland area, and (3) a degree of regulatory instability that may pose a threat to entrepreneurial compensation as a sustainable component of wetland-compensation policy. We used achieved compensation ratios, lapse between bank credit sale and the attainment of performance standards, distance between impact and bank site, and changes in bank market area to examine these 3 factors. We analyzed data from a census of all such transactions in the Chicago District of the U.S. Army Corps of Engineers, compiled from site visits, Corps databases, and contacts with consultants and Section 404 permittees. Entrepreneurial banking provided compensation at a lower overall ratio than nonbank forms of compensation. Approximately 60% of bank credits were sold after site-protection standards were met but before ecological performance standards were met at the bank site. The average distance between bank and impact site was approximately 26 km. The area of markets within which established banks can sell wetland credits has fluctuated considerably over the study period. Comparing these data with similar data for other compensation mechanisms will assist in evaluating banking as an element of conservation policy. Data characterizing the performance of entrepreneurial wetland banks in actual regulatory environments are scarce, even though it is the most established of similar markets that have become instrumental to federal policy in administering several major environmental

Mine-associated wetlands as avian habitat

International Nuclear Information System (INIS)

Horstman, A.J.; Nawrot, J.R.; Woolf, A.

1998-01-01

Surveys for interior wetland birds at mine-associated emergent wetlands on coal surface mines in southern Illinois detected one state threatened and two state endangered species. Breeding by least bittern (Ixobrychus exilis) and common moorhen (Gallinula chloropus) was confirmed. Regional assessment of potential wetland bird habitat south of Illinois Interstate 64 identified a total of 8,109 ha of emergent stable water wetlands; 10% were associated with mining. Mine-associated wetlands with persistent hydrology and large expanses of emergent vegetation provide habitat that could potentially compensate for loss of natural wetlands in Illinois

Development of a "Hydrologic Equivalent Wetland" Concept for Modeling Cumulative Effects of Wetlands on Watershed Hydrology

Science.gov (United States)

Wang, X.; Liu, T.; Li, R.; Yang, X.; Duan, L.; Luo, Y.

2012-12-01

Wetlands are one of the most important watershed microtopographic features that affect, in combination rather than individually, hydrologic processes (e.g., routing) and the fate and transport of constituents (e.g., sediment and nutrients). Efforts to conserve existing wetlands and/or to restore lost wetlands require that watershed-level effects of wetlands on water quantity and water quality be quantified. Because monitoring approaches are usually cost or logistics prohibitive at watershed scale, distributed watershed models, such as the Soil and Water Assessment Tool (SWAT), can be a best resort if wetlands can be appropriately represented in the models. However, the exact method that should be used to incorporate wetlands into hydrologic models is the subject of much disagreement in the literature. In addition, there is a serious lack of information about how to model wetland conservation-restoration effects using such kind of integrated modeling approach. The objectives of this study were to: 1) develop a "hydrologic equivalent wetland" (HEW) concept; and 2) demonstrate how to use the HEW concept in SWAT to assess effects of wetland restoration within the Broughton's Creek watershed located in southwestern Manitoba of Canada, and of wetland conservation within the upper portion of the Otter Tail River watershed located in northwestern Minnesota of the United States. The HEWs were defined in terms of six calibrated parameters: the fraction of the subbasin area that drains into wetlands (WET_FR), the volume of water stored in the wetlands when filled to their normal water level (WET_NVOL), the volume of water stored in the wetlands when filled to their maximum water level (WET_MXVOL), the longest tributary channel length in the subbasin (CH_L1), Manning's n value for the tributary channels (CH_N1), and Manning's n value for the main channel (CH_N2). The results indicated that the HEW concept allows the nonlinear functional relations between watershed processes

Wetland Management - A Success Story In Transition - Restoration of Bhoj Wetland, India

Science.gov (United States)

Mudgal, M. K.; Tech, B. M.; Miwwa

Wetlands are beautiful, biologically diverse, hydrologically disperse and ecological vibrant landscape world wide, embracing soils, water, plants, animals and human be- ing. The population growth in the catchment of wetlands led to multifarious human interventions for deriving maximum benefit from the wetlands and their catchments neglecting and disrespecting the principles of sustainability. This act of destruction has been pronounced in developing countries which are under the grip of poverty, illiteracy and lack of environmental education. SBhoj WetlandS is a Lake situated ´ in Central India, Earthen Dam across the river KOLANS in 1061 AD by then ruler king BHOJ. Till 1950 this Wetland was served as a principal source of water supply, even not requiring filtration. As the city grew and the wetland started getting encir- cled by habitation and urban development, the anthropogenic pressures on the lake increased, thus accelerating the process of eutrophication, making the water unfit for human consumption without due treatment due to deterioration of quality of water. For the conservation and management of Bhoj Wetland (Lake Bhopal) a project is under- taken in the financial assistance from Japan Bank for International Cooperation (JBIC, Japan). The project envisages tackle various issues of conservation and management ofn the wetlands under a multi prongs strategies and manner. Although these issues are deeply interrelated and interlinked but for operational and management ease, these issues have been divided into various sub projects which are being tackled indepen- dently, albeit with undercurrent knowledge and understanding of the related issues and interconnectivity with each other. The Project itself is an apt example of the spectrum of varied problems and issues that come to light when attempts are made for sustain- able conservation and management of a wetland. The Project as envisaged intends to conserve and manage through 14 sub projects as under:- Sub

A generalized regression model of arsenic variations in the shallow groundwater of Bangladesh

Science.gov (United States)

Taylor, Richard G.; Chandler, Richard E.

2015-01-01

Abstract Localized studies of arsenic (As) in Bangladesh have reached disparate conclusions regarding the impact of irrigation‐induced recharge on As concentrations in shallow (≤50 m below ground level) groundwater. We construct generalized regression models (GRMs) to describe observed spatial variations in As concentrations in shallow groundwater both (i) nationally, and (ii) regionally within Holocene deposits where As concentrations in groundwater are generally high (>10 μg L−1). At these scales, the GRMs reveal statistically significant inverse associations between observed As concentrations and two covariates: (1) hydraulic conductivity of the shallow aquifer and (2) net increase in mean recharge between predeveloped and developed groundwater‐fed irrigation periods. Further, the GRMs show that the spatial variation of groundwater As concentrations is well explained by not only surface geology but also statistical interactions (i.e., combined effects) between surface geology and mean groundwater recharge, thickness of surficial silt and clay, and well depth. Net increases in recharge result from intensive groundwater abstraction for irrigation, which induces additional recharge where it is enabled by a permeable surface geology. Collectively, these statistical associations indicate that irrigation‐induced recharge serves to flush mobile As from shallow groundwater. PMID:27524841

Ecology and living conditions of groundwater fauna

Energy Technology Data Exchange (ETDEWEB)

Thulin, Barbara [Geo Innova AB (Sweden); Hahn, Hans Juergen [Arbeitsgruppe Grundwasseroekologie, Univ. of Koblenz-Landau (Germany)

2008-09-15

probable because both Harpatocoida (Parastenocaris sp.) and Nematoda have been detected in the hyporheic zone in rivers and at shores of the Baltic. In addition, groundwater fauna has been reported from other formerly glaciated areas e.g. Northern Germany, Finland, Iceland, Ireland, North America and Siberia and Alpine regions. Glaciofluvial porous aquifers, especially eskers, and karstic aquifers as well as the hyporheic zone, have proved to offer the greatest chances of successful surveys of groundwater fauna. In Sweden endemic species are not expected to be found, except in karstic aquifers in Gotland and Oeland and some parts of the Swedish Mountains. The upper layers of aquifers in crystalline bedrock have only been surveyed at very few sites. Based on community structures of groundwater fauna, reliable statements on the strength of the surface water impact and the vulnerability of the aquifer are possible. Contacts between different water bodies are displayed by groundwater fauna because groundwater fauna communities mainly reflect the intensity of surface water intrusion at a certain point when compared to hydrochemical data indicating the origin of the water. The information provided by the groundwater assemblages of an aquifer can be used for an ecologically based assessment of groundwater. Ecologically based assessment has provided initial data showing that groundwater fauna is a good marker of mixing between surface water and groundwater at certain depths. Ecologically based assessment has hitherto been used for extraction wells and quality management in drinking water abstraction (standards are still to be established). Groundwater fauna assessments have also proved to be useful in management of wetlands and regulation under nature protection law

Ecology and living conditions of groundwater fauna

International Nuclear Information System (INIS)

Thulin, Barbara; Hahn, Hans Juergen

2008-09-01

probable because both Harpatocoida (Parastenocaris sp.) and Nematoda have been detected in the hyporheic zone in rivers and at shores of the Baltic. In addition, groundwater fauna has been reported from other formerly glaciated areas e.g. Northern Germany, Finland, Iceland, Ireland, North America and Siberia and Alpine regions. Glaciofluvial porous aquifers, especially eskers, and karstic aquifers as well as the hyporheic zone, have proved to offer the greatest chances of successful surveys of groundwater fauna. In Sweden endemic species are not expected to be found, except in karstic aquifers in Gotland and Oeland and some parts of the Swedish Mountains. The upper layers of aquifers in crystalline bedrock have only been surveyed at very few sites. Based on community structures of groundwater fauna, reliable statements on the strength of the surface water impact and the vulnerability of the aquifer are possible. Contacts between different water bodies are displayed by groundwater fauna because groundwater fauna communities mainly reflect the intensity of surface water intrusion at a certain point when compared to hydrochemical data indicating the origin of the water. The information provided by the groundwater assemblages of an aquifer can be used for an ecologically based assessment of groundwater. Ecologically based assessment has provided initial data showing that groundwater fauna is a good marker of mixing between surface water and groundwater at certain depths. Ecologically based assessment has hitherto been used for extraction wells and quality management in drinking water abstraction (standards are still to be established). Groundwater fauna assessments have also proved to be useful in management of wetlands and regulation under nature protection law

Atrazine remediation in wetland microcosms.

Science.gov (United States)

Runes, H B; Bottomley, P J; Lerch, R N; Jenkins, J J

2001-05-01

Laboratory wetland microcosms were used to study treatment of atrazine in irrigation runoff by a field-scale-constructed wetland under controlled conditions. Three experiments, in which 1 ppm atrazine was added to the water column of three wetland, one soil control, and one water control microcosm, were conducted. Atrazine dissipation from the water column and degradate formation (deethylatrazine [DEA]; deisopropylatrazine [DIA]; and hydroxyatrazine [HA]) were monitored. Atrazine dissipation from the water column of wetland microcosms was biphasic. Less than 12% of the atrazine applied to wetland microcosms remained in the water column on day 56. Atrazine degradates were observed in water and sediment, with HA the predominant degradate. Analysis of day 56 sediment samples indicated that a significant portion of the initial application was detected as the parent compound and HA. Most probable number (MPN) assays demonstrated that atrazine degrader populations were small in wetland sediment. Wetland microcosms were able to reduce atrazine concentration in the water column via sorption and degradation. Based on results from this study, it is hypothesized that plant uptake contributed to atrazine dissipation from the water column.

Vegetation-induced spatial variability of soil redox properties in wetlands

Science.gov (United States)

Szalai, Zoltán; Jakab, Gergely; Kiss, Klaudia; Ringer, Marianna; Balázs, Réka; Zacháry, Dóra; Horváth Szabó, Kata; Perényi, Katalin

2016-04-01

Vegetation induced land patches may result spatial pattern of on soil Eh and pH. These spatial pattern are mainly emerged by differences of aeration and exudation of assimilates. Present paper focuses on vertical extent and temporal dynamics of these patterns in wetlands. Two study sites were selected: 1. a plain wetland on calcareous sandy parent material (Ceglédbercel, Danube-Tisza Interfluve, Hungary); 2. headwater wetland with calcareous loamy parent material (Bátaapáti, Hungary). Two vegetation patches were studied in site 1: sedgy (dominated by Carex riparia) and reedy (dominated by Phragmites australis). Three patches were studied in site2: sedgy1 (dominated by C vulpina), sedgy 2 (C. riparia); nettle-horsetail (Urtica dioica and Equisetum arvense). Boundaries between patches were studied separately. Soil redox, pH and temperature studied by automated remote controlled instruments. Three digital sensors (Ponsell) were installed in each locations: 20cm and 40cm sensors represent the solum and 100 cm sensor monitors the subsoil). Groundwater wells were installed near to triplets for soil water sampling. Soil Eh, pH and temperature values were recorded in each 10 minutes. Soil water sampling for iron and DOC were carried out during saturated periods. Spatial pattern of soil Eh is clearly caused by vegetation. We measured significant differences between Eh values of the studied patches in the solum. We did not find this kinds horizontal differences in the subsoil. Boundaries of the patches usually had more reductive soil environment than the core areas. We have found temporal dynamics of the spatial redox pattern. Differences were not so well expressed during wintertime. These spatial patterns had influence on the DOC and iron content of porewater, as well. Highest temporal dynamics of soil redox properties and porewater iron could be found in the boundaries. These observations refer to importance patchiness of vegetation on soil chemical properties in

Remotely sensed MODIS wetland components for assessing the variability of methane emissions in Indian tropical/subtropical wetlands

Science.gov (United States)

Bansal, Sangeeta; Katyal, Deeksha; Saluja, Ridhi; Chakraborty, Monojit; Garg, J. K.

2018-02-01

Temperature and area fluctuations in wetlands greatly influence its various physico-chemical characteristics, nutrients dynamic, rates of biomass generation and decomposition, floral and faunal composition which in turn influence methane (CH4) emission rates. In view of this, the present study attempts to up-scale point CH4 flux from the wetlands of Uttar Pradesh (UP) by modifying two-factor empirical process based CH4 emission model for tropical wetlands by incorporating MODIS derived wetland components viz. wetland areal extent and corresponding temperature factors (Ft). This study further focuses on the utility of remotely sensed temperature response of CH4 emission in terms of Ft. Ft is generated using MODIS land surface temperature products and provides an important semi-empirical input for up-scaling CH4 emissions in wetlands. Results reveal that annual mean Ft values for UP wetlands vary from 0.69 (2010-2011) to 0.71(2011-2012). The total estimated area-wise CH4 emissions from the wetlands of UP varies from 66.47 Gg yr-1with wetland areal extent and Ft value of 2564.04 km2 and 0.69 respectively in 2010-2011 to 88.39 Gg yr-1with wetland areal extent and Ft value of 2720.16 km2 and 0.71 respectively in 2011-2012. Temporal analysis of estimated CH4 emissions showed that in monsoon season estimated CH4 emissions are more sensitive to wetland areal extent while in summer season sensitivity of estimated CH4 emissions is chiefly controlled by augmented methanogenic activities at high wetland surface temperatures.

Use of constructed wetland for the removal of heavy metals from industrial wastewater.

Science.gov (United States)

Khan, Sardar; Ahmad, Irshad; Shah, M Tahir; Rehman, Shafiqur; Khaliq, Abdul

2009-08-01

This study was conducted to investigate the effectiveness of a continuous free surface flow wetland for removal of heavy metals from industrial wastewater, in Gadoon Amazai Industrial Estate (GAIE), Swabi, Pakistan. Industrial wastewater samples were collected from the in-let, out-let and all cells of the constructed wetland (CW) and analyzed for heavy metals such as lead (Pb), cadmium (Cd), iron (Fe), nickel (Ni), chromium (Cr) and copper (Cu) using standard methods. Similarly, samples of aquatic macrophytes and sediments were also analyzed for selected heavy metals. Results indicate that the removal efficiencies of the CW for Pb, Cd, Fe, Ni, Cr, and Cu were 50%, 91.9%, 74.1%, 40.9%, 89%, and 48.3%, respectively. Furthermore, the performance of the CW was efficient enough to remove the heavy metals, particularly Cd, Fe, and Cu, from the industrial wastewater fed to it. However, it is suggested that the metal removal efficiency of the CW can be further enhanced by using proper management of vegetation and area expansion of the present CW.

Human wetland dependency and socio-economic evaluation of wetland functions through participatory approach in rural India

Directory of Open Access Journals (Sweden)

Malabika Biswas

2010-12-01

Full Text Available Wetlands are an important source of natural resources upon which rural economies depend. They have increasingly been valuable for their goods and services, and the intrinsic ecological value they provide to local populations, as well as people living outside the periphery of the wetlands. Stakeholders' participation is essential to the protection and preservation of wetlands because it plays a very important role economically as well as ecologically in the wetland system. The objective of this study was to determine whether gender, educational status, mouzas (which are constituents of a block according to the land reform of the West Bengal Government in India, and wetland functions have any influence on the annual income of the local community. Considering a floodplain wetland in rural India, the focus was extended to recognize the pattern of wetland functions according to the nature of people's involvement through cluster analysis of the male and female populations. Using the statistical software R-2.8.1, an ANOVA (analysis of variance table was constructed. Since the p value (significance level was lower than 0.05 for each case, it can be concluded that gender, educational status, mouzas, and wetland functions have a significant influence on annual income. However, S-PLUS-2000 was applied to obtain a complete scenario of the pattern of wetland functions, in terms of involvement of males and females, through cluster analysis. The main conclusion is that gender, educational status, mouzas, and wetland functions have significant impacts on annual income, while the pattern of occupation of the local community based on wetland functions is completely different for the male and female populations.

Climate Change and Intertidal Wetlands

Directory of Open Access Journals (Sweden)

Pauline M. Ross

2013-03-01

Full Text Available Intertidal wetlands are recognised for the provision of a range of valued ecosystem services. The two major categories of intertidal wetlands discussed in this contribution are saltmarshes and mangrove forests. Intertidal wetlands are under threat from a range of anthropogenic causes, some site-specific, others acting globally. Globally acting factors include climate change and its driving cause—the increasing atmospheric concentrations of greenhouse gases. One direct consequence of climate change will be global sea level rise due to thermal expansion of the oceans, and, in the longer term, the melting of ice caps and glaciers. The relative sea level rise experienced at any one locality will be affected by a range of factors, as will the response of intertidal wetlands to the change in sea level. If relative sea level is rising and sedimentation within intertidal wetlands does not keep pace, then there will be loss of intertidal wetlands from the seaward edge, with survival of the ecosystems only possible if they can retreat inland. When retreat is not possible, the wetland area will decline in response to the “squeeze” experienced. Any changes to intertidal wetland vegetation, as a consequence of climate change, will have flow on effects to biota, while changes to biota will affect intertidal vegetation. Wetland biota may respond to climate change by shifting in distribution and abundance landward, evolving or becoming extinct. In addition, impacts from ocean acidification and warming are predicted to affect the fertilisation, larval development, growth and survival of intertidal wetland biota including macroinvertebrates, such as molluscs and crabs, and vertebrates such as fish and potentially birds. The capacity of organisms to move and adapt will depend on their life history characteristics, phenotypic plasticity, genetic variability, inheritability of adaptive characteristics, and the predicted rates of environmental change.

Climate change and intertidal wetlands.

Science.gov (United States)

Ross, Pauline M; Adam, Paul

2013-03-19

Intertidal wetlands are recognised for the provision of a range of valued ecosystem services. The two major categories of intertidal wetlands discussed in this contribution are saltmarshes and mangrove forests. Intertidal wetlands are under threat from a range of anthropogenic causes, some site-specific, others acting globally. Globally acting factors include climate change and its driving cause-the increasing atmospheric concentrations of greenhouse gases. One direct consequence of climate change will be global sea level rise due to thermal expansion of the oceans, and, in the longer term, the melting of ice caps and glaciers. The relative sea level rise experienced at any one locality will be affected by a range of factors, as will the response of intertidal wetlands to the change in sea level. If relative sea level is rising and sedimentation within intertidal wetlands does not keep pace, then there will be loss of intertidal wetlands from the seaward edge, with survival of the ecosystems only possible if they can retreat inland. When retreat is not possible, the wetland area will decline in response to the "squeeze" experienced. Any changes to intertidal wetland vegetation, as a consequence of climate change, will have flow on effects to biota, while changes to biota will affect intertidal vegetation. Wetland biota may respond to climate change by shifting in distribution and abundance landward, evolving or becoming extinct. In addition, impacts from ocean acidification and warming are predicted to affect the fertilisation, larval development, growth and survival of intertidal wetland biota including macroinvertebrates, such as molluscs and crabs, and vertebrates such as fish and potentially birds. The capacity of organisms to move and adapt will depend on their life history characteristics, phenotypic plasticity, genetic variability, inheritability of adaptive characteristics, and the predicted rates of environmental change.

SLOSS or Not? Factoring Wetland Size Into Decisions for Wetland Conservation, Enhancement, Restoration, and Creation

Science.gov (United States)

Mitigation or replacement of several small impacted wetlands or sites with fewer large wetlands can occur deliberately through the application of functional assessment methods (e.g., Adamus 1997) or coincidentally as the result of market-based mechanisms for wetland mitigation ba...

Working group report on wetlands and wildlife

International Nuclear Information System (INIS)

Teels, B.

1991-01-01

The results and conclusions of a working group held to discuss the state of knowledge and knowledge gaps concerning climatic change impacts on wetlands and wildlife are presented. Prairie pothole wetlands are extremely productive and produce ca 50% of all ducks in North America. The most productive, and most vulnerable to climate change, are small potholes, often less than one acre in area. Changes in water regimes and land use will have more impact on wildlife than changes in temperature. There are gaps in knowledge relating to: boreal wetlands and their wildlife, and response to climate; wetland inventories that include the smallest wetlands; coordinated schemes for monitoring status and trends of wetlands and wildlife; and understanding of ecological relationships within wetlands and their wildlife communities. Recommendations include: coordinate and enhance existing databases to provide an integrated monitoring system; establish research programs to increase understanding of ecological relationships within wetland ecosystems; evaluate programs and policies that affect wetlands; and promote heightened public awareness of general values of wetlands

Remote sensing of wetlands applications and advances

CERN Document Server

Tiner, Ralph W; Klemas, Victor V

2015-01-01

Effectively Manage Wetland Resources Using the Best Available Remote Sensing Techniques Utilizing top scientists in the wetland classification and mapping field, Remote Sensing of Wetlands: Applications and Advances covers the rapidly changing landscape of wetlands and describes the latest advances in remote sensing that have taken place over the past 30 years for use in mapping wetlands. Factoring in the impact of climate change, as well as a growing demand on wetlands for agriculture, aquaculture, forestry, and development, this text considers the challenges that wetlands pose for remote sensing and provides a thorough introduction on the use of remotely sensed data for wetland detection. Taking advantage of the experiences of more than 50 contributing authors, the book describes a variety of techniques for mapping and classifying wetlands in a multitude of environments ranging from tropical to arctic wetlands including coral reefs and submerged aquatic vegetation. The authors discuss the advantages and di...

Engineered wetlands : an innovative environmental solution

International Nuclear Information System (INIS)

Wallace, S.; Davis, B.M.

2008-01-01

Engineered wetlands are now considered as an emerging technology for the in situ remediation of hydrocarbon-contaminated soil and waters. Engineered wetlands incorporate a horizontal subsurface flow gravel bed reactor lined with impermeable liners, and are equipped with forced bed aeration systems in order to enhance oxygen delivery to the wetland's aerobic micro-organisms. The wetlands typically emphasize specific characteristics of wetland ecosystems to improve treatment capacities. This article discussed an engineered wetlands installed at a set of pipeline terminals as well as at a former British Petroleum (BP) refinery. The pipeline terminal generated contact wastewater containing BTEX and ammonia, and a subsurface engineered wetland was built in 1998. To date, the 16,000 2 foot wetland has treated a flow-equalized input of approximately 1.5 m 3 per day of contaminants. At the refinery, a wetland treatment system was designed to treat 6000 m 3 of benzene, toluene, ethylbenzene and xylene (BTEX) and volatile organic compounds (VOCs). The treatment site consists of a golf course, river front trails, and a white water kayak course. A cascade aeration system was used for iron oxidation and air-stripping. A soil matrix biofilter was used for passive gas phase benzene removal, as well as for the removal of ferric hydroxide precipitates. It was concluded that engineered wetlands can offer long-term solutions to site remediation challenges. 1 fig

The nitrogen abatement cost in wetlands

International Nuclear Information System (INIS)

Bystroem, Olof

1998-01-01

The costs of abating agricultural nitrogen pollution in wetlands are estimated. By linking costs for construction of wetlands to the denitrification capacity of wetlands, an abatement cost function can be formed. A construction-cost function and a denitrification function for wetlands is estimated empirically. This paper establishes a link between abatement costs and the nitrogen load on wetlands. Since abatement costs fluctuate with nitrogen load, ignoring this link results in incorrect estimates of abatement costs. The results demonstrate that wetlands have the capacity to provide low cost abatement of nitrogen compounds in runoff. For the Kattegatt region in Sweden, marginal abatement costs for wetlands are shown to be lower than costs of land use changing measures, such as extended land under fallow or cultivation of fuel woods, but higher than the marginal costs of reducing nitrogen fertilizer

40 CFR 257.9 - Wetlands.

Science.gov (United States)

2010-07-01

... not locate such units in wetlands, unless the owner or operator can make the following demonstrations... actions (e.g., restoration of existing degraded wetlands or creation of man-made wetlands); and (5) Sufficient information is available to make a reasonable determination with respect to these demonstrations...

Conservation of Mexican wetlands: role of the North American Wetlands Conservation Act

Science.gov (United States)

Wilson, M.H.; Ryan, D.A.

1997-01-01

Mexico's wetlands support a tremendous biological diversity and provide significant natural resource benefits to local communities. Because they are also critical stopover and wintering grounds for much of North America's waterfowl and other migratory birds, Mexico has become an important participant in continental efforts to conserve these resources through the North American Wetlands Conservation Act. Funding from the Act has supported partnerships in a number of Mexico's priority wetlands to conduct data analyses and dissemination, mapping, environmental education, wetland restoration, development of sustainable economic alternatives for local people, and reserve planning and management. These partnerships, with the close involvement of Mexico's Federal Government authority, the Instituto Nacional de Ecologia, have advanced conservation in a uniquely Mexican model that differs from that employed in the United States and Canada.

Design-a-wetland: a tool for generating and assessing constructed wetland designs for wastewater treatment

International Nuclear Information System (INIS)

Casaril, Carolina J.

2007-01-01

Full text: Full text: The hydrological cycle is a key cycle affected by current and predicted climate change. Wetlands are one of the key ecosystems within the hydrological cycle and could contribute significantly in facing the challenges of climate change, such as water shortage. The impact of wetlands on greenhouse gas emissions is much debated and, conversely, the impact of climate change on wetlands also raises many questions. There have been many attempts to harness and integrate the natural capacities of wetlands into constructed systems. These systems are especially designed for multiple purposes. They can be used for wastewater treatment and reuse, and have the potential to increase sustainability by changing land and water use practices. This project generates a 'Design-A-Wetland' prototype model, designed to facilitate decision-making in the creation of constructed wetlands. Constructed wetlands are specifically tailored to their end use; water treatment fish and fowl habitat, flood buffer zones, or sequestration of greenhouse gases. This project attempts to answer the following questions: Can a single integrated decision model be created for the design and assessment of artificial wetlands, provided either entry or exit standards are known and specified?; Can the elements of a system of interfacing the model with public consultation be specified?; The project identifies model schematics and lays the groundwork for modelling suited to the wide variety of inputs required for decision making

Flood pulsing in the Sudd wetland: analysis of seasonal variations in 2 inundation and evapotranspiration in Southern Sudan

Science.gov (United States)

Senay, Gabriel B.; Rebelo, L-M.; McCartney, M.P.

2012-01-01

Located on the Bahr el Jebel in South Sudan, the Sudd is one of the largest floodplain wetlands in the world. Seasonal inundation drives the hydrologic, geomorphological, and ecological processes, and the annual flood pulse is essential to the functioning of the Sudd. Despite the importance of the flood pulse, various hydrological interventions are planned upstream of the Sudd to increase economic benefits and food security. These will not be without consequences, in particular for wetlands where the biological productivity, biodiversity, and human livelihoods are dependent on the flood pulse and both the costs and benefits need to be carefully evaluated. Many African countries still lack regional baseline information on the temporal extent, distribution, and characteristics of wetlands, making it hard to assess the consequences of development interventions. Because of political instability in Sudan and the inaccessible nature of the Sudd, recent measurements of flooding and seasonal dynamics are inadequate. Analyses of multitemporal and multisensor remote sensing datasets are presented in this paper, in order to investigate and characterize flood pulsing within the Sudd wetland over a 12-month period. Wetland area has been mapped along with dominant components of open water and flooded vegetation at five time periods over a single year. The total area of flooding (both rain and river fed) over the 12 months was 41 334 km2, with 9176 km2 of this constituting the permanent wetland. Mean annual total evaporation is shown to be higher and with narrower distribution of values from areas of open water (1718 mm) than from flooded vegetation (1641 mm). Although the exact figures require validation against ground-based measurements, the results highlight the relative differences in inundation patterns and evaporation across the Sudd.

Groundwater recharge and sustainability in the High Plains aquifer in Kansas, USA

Science.gov (United States)

Sophocleous, M.

2005-01-01

Sustainable use of groundwater must ensure not only that the future resource is not threatened by overuse, but also that natural environments that depend on the resource, such as stream baseflows, riparian vegetation, aquatic ecosystems, and wetlands are protected. To properly manage groundwater resources, accurate information about the inputs (recharge) and outputs (pumpage and natural discharge) within each groundwater basin is needed so that the long-term behavior of the aquifer and its sustainable yield can be estimated or reassessed. As a first step towards this effort, this work highlights some key groundwater recharge studies in the Kansas High Plains at different scales, such as regional soil-water budget and groundwater modeling studies, county-scale groundwater recharge studies, as well as field-experimental local studies, including some original new findings, with an emphasis on assumptions and limitations as well as on environmental factors affecting recharge processes. The general impact of irrigation and cultivation on recharge is to appreciably increase the amount of recharge, and in many cases to exceed precipitation as the predominant source of recharge. The imbalance between the water input (recharge) to the High Plains aquifer and the output (pumpage and stream baseflows primarily) is shown to be severe, and responses to stabilize the system by reducing water use, increasing irrigation efficiency, adopting water-saving land-use practices, and other measures are outlined. Finally, the basic steps necessary to move towards sustainable use of groundwater in the High Plains are delineated, such as improving the knowledge base, reporting and providing access to information, furthering public education, as well as promoting better understanding of the public's attitudinal motivations; adopting the ecosystem and adaptive management approaches to managing groundwater; further improving water efficiency; exploiting the full potential of dryland and

Engineered wetlands : an innovative environmental solution

Energy Technology Data Exchange (ETDEWEB)

Wallace, S.; Davis, B.M. [Jacques Whitford NAWE, White Bear Lake, MN (United States)

2008-03-15

Engineered wetlands are now considered as an emerging technology for the in situ remediation of hydrocarbon-contaminated soil and waters. Engineered wetlands incorporate a horizontal subsurface flow gravel bed reactor lined with impermeable liners, and are equipped with forced bed aeration systems in order to enhance oxygen delivery to the wetland's aerobic micro-organisms. The wetlands typically emphasize specific characteristics of wetland ecosystems to improve treatment capacities. This article discussed an engineered wetlands installed at a set of pipeline terminals as well as at a former British Petroleum (BP) refinery. The pipeline terminal generated contact wastewater containing BTEX and ammonia, and a subsurface engineered wetland was built in 1998. To date, the 16,000{sup 2} foot wetland has treated a flow-equalized input of approximately 1.5 m{sup 3} per day of contaminants. At the refinery, a wetland treatment system was designed to treat 6000 m{sup 3} of benzene, toluene, ethylbenzene and xylene (BTEX) and volatile organic compounds (VOCs). The treatment site consists of a golf course, river front trails, and a white water kayak course. A cascade aeration system was used for iron oxidation and air-stripping. A soil matrix biofilter was used for passive gas phase benzene removal, as well as for the removal of ferric hydroxide precipitates. It was concluded that engineered wetlands can offer long-term solutions to site remediation challenges. 1 fig.

Wetlands and infectious diseases

Directory of Open Access Journals (Sweden)

Robert H. Zimmerman

2001-01-01

Full Text Available There is a historical association between wetlands and infectious disease that has led to the modification of wetlands to prevent disease. At the same time there has been the development of water resources projects that increase the risk of disease. The demand for more water development projects and the increased pressure to make natural wetlands economically beneficial creates the need for an ecological approach to wetland management and health assessment. The environmental and health interactions are many. There is a need to take into account the landscape, spatial boundaries, and cross-boundary interactions in water development projects as well as alternative methods to provide water for human needs. The research challenges that need to be addressed are discussed.

Evidence for a climate-induced ecohydrological state shift in wetland ecosystems of the southern Prairie Pothole Region

Science.gov (United States)

McKenna, Owen; Mushet, David M.; Rosenberry, Donald O.; LaBaugh, James W.

2017-01-01

Changing magnitude, frequency, and timing of precipitation can influence aquatic-system hydrological, geochemical, and biological processes, in some cases resulting in system-wide shifts to an alternate state. Since the early 1990s, the southern Prairie Pothole Region has been subjected to an extended period of increased wetness resulting in marked changes to aquatic systems defining this region. We explored numerous lines of evidence to identify: (1) how the recent wet period compared to historical variability, (2) hydrological, geochemical, and biological responses, and (3) how these responses might represent a state shift in the region’s wetland ecosystems. We analyzed long-term climate records and compared how different hydrological variables responded in this wet period compared to decades before the observed shift. Additionally, we used multi-decadal records of waterfowl population and subsurface tile drain records to explore wildlife and human responses to a shifting climate. Since 1993, a novel precipitation regime corresponded with increased pond numbers, ponded-water depths, lake levels, stream flows, groundwater heights, soil-moisture, waterfowl populations, and installation of subsurface tile drains in agricultural fields. These observed changes reflect an alteration in water storage and movement across the landscape that in turn has altered solute sources and concentrations of prairie-pothole wetlands and has increased pond permanence. Combined, these changes represent significant evidence for a state shift in the ecohydrological functioning of the region’s wetland ecosystems, a shift that may require a significant refinement of the previously developed “wetland continuum” concept.

North American Wetlands and Mosquito Control

Science.gov (United States)

Rey, Jorge R.; Walton, William E.; Wolfe, Roger J.; Connelly, Roxanne; O’Connell, Sheila M.; Berg, Joe; Sakolsky-Hoopes, Gabrielle E.; Laderman, Aimlee D.

2012-01-01

Wetlands are valuable habitats that provide important social, economic, and ecological services such as flood control, water quality improvement, carbon sequestration, pollutant removal, and primary/secondary production export to terrestrial and aquatic food chains. There is disagreement about the need for mosquito control in wetlands and about the techniques utilized for mosquito abatement and their impacts upon wetlands ecosystems. Mosquito control in wetlands is a complex issue influenced by numerous factors, including many hard to quantify elements such as human perceptions, cultural predispositions, and political climate. In spite of considerable progress during the last decades, habitat protection and environmentally sound habitat management still remain inextricably tied to politics and economics. Furthermore, the connections are often complex, and occur at several levels, ranging from local businesses and politicians, to national governments and multinational institutions. Education is the key to lasting wetlands conservation. Integrated mosquito abatement strategies incorporate many approaches and practicable options, as described herein, and need to be well-defined, effective, and ecologically and economically sound for the wetland type and for the mosquito species of concern. The approach will certainly differ in response to disease outbreaks caused by mosquito-vectored pathogens versus quality of life issues caused by nuisance-biting mosquitoes. In this contribution, we provide an overview of the ecological setting and context for mosquito control in wetlands, present pertinent information on wetlands mosquitoes, review the mosquito abatement options available for current wetlands managers and mosquito control professionals, and outline some necessary considerations when devising mosquito control strategies. Although the emphasis is on North American wetlands, most of the material is applicable to wetlands everywhere. PMID:23222252

Methane emissions from global wetlands: An assessment of the uncertainty associated with various wetland extent data sets

Science.gov (United States)

Zhang, Bowen; Tian, Hanqin; Lu, Chaoqun; Chen, Guangsheng; Pan, Shufen; Anderson, Christopher; Poulter, Benjamin

2017-09-01

A wide range of estimates on global wetland methane (CH4) fluxes has been reported during the recent two decades. This gives rise to urgent needs to clarify and identify the uncertainty sources, and conclude a reconciled estimate for global CH4 fluxes from wetlands. Most estimates by using bottom-up approach rely on wetland data sets, but these data sets show largely inconsistent in terms of both wetland extent and spatiotemporal distribution. A quantitative assessment of uncertainties associated with these discrepancies among wetland data sets has not been well investigated yet. By comparing the five widely used global wetland data sets (GISS, GLWD, Kaplan, GIEMS and SWAMPS-GLWD), it this study, we found large differences in the wetland extent, ranging from 5.3 to 10.2 million km2, as well as their spatial and temporal distributions among the five data sets. These discrepancies in wetland data sets resulted in large bias in model-estimated global wetland CH4 emissions as simulated by using the Dynamic Land Ecosystem Model (DLEM). The model simulations indicated that the mean global wetland CH4 emissions during 2000-2007 were 177.2 ± 49.7 Tg CH4 yr-1, based on the five different data sets. The tropical regions contributed the largest portion of estimated CH4 emissions from global wetlands, but also had the largest discrepancy. Among six continents, the largest uncertainty was found in South America. Thus, the improved estimates of wetland extent and CH4 emissions in the tropical regions and South America would be a critical step toward an accurate estimate of global CH4 emissions. This uncertainty analysis also reveals an important need for our scientific community to generate a global scale wetland data set with higher spatial resolution and shorter time interval, by integrating multiple sources of field and satellite data with modeling approaches, for cross-scale extrapolation.

Percent Wetland Cover (Future)

Data.gov (United States)

U.S. Environmental Protection Agency — Wetlands act as filters, removing or diminishing the amount of pollutants that enter surface water. Higher values for percent of wetland cover (WETLNDSPCT) may be...

VSWI Wetlands Advisory Layer

Data.gov (United States)

Vermont Center for Geographic Information — This dataset represents the DEC Wetlands Program's Advisory layer. This layer makes the most up-to-date, non-jurisdictional, wetlands mapping avaiable to the public...

Lake Superior Coastal Wetland Fish Assemblages and ...

Science.gov (United States)

The role of the coastal margin and the watershed context in defining the ecology of even very large lakes is increasingly being recognized and examined. Coastal wetlands are both important contributors to the biodiversity and productivity of large lakes and important mediators of the lake-basin connection. We explored wetland-watershed connections and their relationship to wetland function and condition using data collected from 37 Lake Superior wetlands spanning a substantial geographic and geomorphic gradient. While none of these wetlands are particularly disturbed, there were nevertheless clear relationships between watershed landuse and wetland habitat and biota, and these varied consistently across wetland type categories that reflected the strength of connection to the watershed. For example, water clarity and vegetation structure complexity declined with decreasing percent natural land cover, and these effects were strongest in riverine wetlands (having generally large watersheds and tributary-dominated hydrology) and weakest in lagoon wetlands (having generally small watersheds and lake-dominate hydrology). Fish abundance and species richness both increased with decreasing percent natural land cover while species diversity decreased, and again the effect was strongest in riverine wetlands. Lagoonal wetlands, which lack any substantial tributary, consistently harbored the fewest species of fish and a composition different from the more watershed-lin

Using radon-222 to study coastal groundwater/surface-water interaction in the Crau coastal aquifer (southeastern France)

Science.gov (United States)

Mayer, Adriano; Nguyen, Bach Thao; Banton, Olivier

2016-11-01

Radon has been used to determine groundwater velocity and groundwater discharge into wetlands at the southern downstream boundary of the Crau aquifer, southeastern France. This aquifer constitutes an important high-quality freshwater resource exploited for agriculture, industry and human consumption. An increase in salinity occurs close to the sea, highlighting the need to investigate the water balance and groundwater behavior. Darcy velocity was estimated using radon activities in well waters according to the Hamada "single-well method" (involving comparison with radon in groundwater in the aquifer itself). Measurements done at three depths (7, 15 and 21 m) provided velocity ranging from a few mm/day to more than 20 cm/day, with highest velocities observed at the 15-m depth. Resulting hydraulic conductivities agree with the known geology. Waters showing high radon activity and high salinity were found near the presumed shoreline at 3,000 years BP, highlighting the presence of ancient saltwater. Radon activity has also been measured in canals, rivers and ponds, to trace groundwater discharges and evaluate water balance. A model of the radon spatial evolution explains the observed radon activities. Groundwater discharge to surface water is low in pond waters (4 % of total inputs) but significant in canals (55 l/m2/day).

Diverse characteristics of wetlands restored under the Wetlands Reserve Program in the Southeastern United States

Science.gov (United States)

Diane De Steven; Joel M. Gramling

2012-01-01

The Wetlands Reserve Program (WRP) restores converted or degraded wetlands on private working lands; however, the nature and outcomes of such efforts are undocumented in the Southeastern U.S. Identification of wetland types is needed to assess the program's conservation benefits, because ecological functions differ with hydrogeomorphic (HGM) type. We reviewed...

Hydrologic connectivity to streams increases nitrogen and phosphorus inputs and cycling in soils of created and natural floodplain wetlands

Science.gov (United States)

Wolf, Kristin L.; Noe, Gregory; Ahn, Changwoo

2013-01-01

Greater connectivity to stream surface water may result in greater inputs of allochthonous nutrients that could stimulate internal nitrogen (N) and phosphorus (P) cycling in natural, restored, and created riparian wetlands. This study investigated the effects of hydrologic connectivity to stream water on soil nutrient fluxes in plots (n = 20) located among four created and two natural freshwater wetlands of varying hydrology in the Piedmont physiographic province of Virginia. Surface water was slightly deeper; hydrologic inputs of sediment, sediment-N, and ammonium were greater; and soil net ammonification, N mineralization, and N turnover were greater in plots with stream water classified as their primary water source compared with plots with precipitation or groundwater as their primary water source. Soil water-filled pore space, inputs of nitrate, and soil net nitrification, P mineralization, and denitrification enzyme activity (DEA) were similar among plots. Soil ammonification, N mineralization, and N turnover rates increased with the loading rate of ammonium to the soil surface. Phosphorus mineralization and ammonification also increased with sedimentation and sediment-N loading rate. Nitrification flux and DEA were positively associated in these wetlands. In conclusion, hydrologic connectivity to stream water increased allochthonous inputs that stimulated soil N and P cycling and that likely led to greater retention of sediment and nutrients in created and natural wetlands. Our findings suggest that wetland creation and restoration projects should be designed to allow connectivity with stream water if the goal is to optimize the function of water quality improvement in a watershed.

Fresh meteoric versus recirculated saline groundwater nutrient inputs into a subtropical estuary

Energy Technology Data Exchange (ETDEWEB)

Sadat-Noori, Mahmood, E-mail: mahmood.sadat-noori@scu.edu.au [National Marine Science Centre, School of Environment, Science and Engineering, Southern Cross University, Coffs Harbour, NSW (Australia); School of Environment, Science and Engineering, Southern Cross University, Lismore, NSW (Australia); Santos, Isaac R. [National Marine Science Centre, School of Environment, Science and Engineering, Southern Cross University, Coffs Harbour, NSW (Australia); Tait, Douglas R. [National Marine Science Centre, School of Environment, Science and Engineering, Southern Cross University, Coffs Harbour, NSW (Australia); School of Environment, Science and Engineering, Southern Cross University, Lismore, NSW (Australia); Maher, Damien T. [School of Environment, Science and Engineering, Southern Cross University, Lismore, NSW (Australia)

2016-10-01

The role of groundwater in transporting nutrients to coastal aquatic systems has recently received considerable attention. However, the relative importance of fresh versus saline groundwater-derived nutrient inputs to estuaries and how these groundwater pathways may alter surface water N:P ratios remains poorly constrained. We performed detailed time series measurements of nutrients in a tidal estuary (Hat Head, NSW, Australia) and used radium to quantify the contribution of fresh and saline groundwater to total surface water estuarine exports under contrasting hydrological conditions (wet and dry season). Tidally integrated nutrient fluxes showed that the estuary was a source of nutrients to the coastal waters. Dissolved inorganic nitrogen (DIN) export was 7-fold higher than the average global areal flux rate for rivers likely due to the small catchment size, surrounding wetlands and high groundwater inputs. Fresh groundwater discharge was dominant in the wet season accounting for up to 45% of total dissolved nitrogen (TDN) and 48% of total dissolved phosphorus (TDP) estuarine exports. In the dry season, fresh and saline groundwater accounted for 21 and 33% of TDN export, respectively. The combined fresh and saline groundwater fluxes of NO{sub 3}, PO{sub 4}, NH{sub 4}, DON, DOP, TDN and TDP were estimated to account for 66, 58, 55, 31, 21, 53 and 47% of surface water exports, respectively. Groundwater-derived nitrogen inputs to the estuary were responsible for a change in the surface water N:P ratio from typical N-limiting conditions to P-limiting as predicted by previous studies. This shows the importance of both fresh and saline groundwater as a source of nutrients for coastal productivity and nutrient budgets of coastal waters. - Highlights: • Groundwater TDN and TDP fluxes account for 53 and 47% of surface water exports. • The estuary DIN export was 7-fold higher than the average global areal flux. • Fresh GW nutrient input dominated the wet season and

The emergence of treatment wetlands

International Nuclear Information System (INIS)

Cole, S.

1998-01-01

Judging by the growing number of wetlands built for wastewater treatment around the world, this natural technology seems to have firmly established roots. After almost 30 years of use in wastewater treatment, constructed treatment wetlands now number over 500 in Europe and 600 in North America. Marsh-type surface flow systems are most common in North America, but subsurface flow wetlands, where wastewater flows beneath the surface of a gravel-rock bed, predominate in Europe. The inexpensive, low maintenance technology is in high demand in Central America, Eastern Europe, and Asia. New applications, from nitrate-contaminated ground water to effluent from high-intensity livestock operations, are also increasing. But in the United States, treatment-wetland technology has not yet gained national regulatory acceptance. Some states and EPA regions are eager to endorse them, but others are wary of this nontraditional method of treating wastewater. In part, this reluctance exists because the technology is not yet completely understood. Treatment wetlands also pose a potential threat to wildlife attracted to this new habitat -an ecosystem exposed to toxic compounds. New efforts are under way, however, to place the technology onto firmer scientific and regulatory ground. Long-term demonstration and monitoring field studies are currently probing the inner workings of wetlands and their water quality capabilities to provide better data on how to design more effective systems. A recent study of US policy and regulatory issues surrounding treatment wetlands has recommended that the federal government actively promote the technology and clear the regulatory roadblocks to enable wider use. Proponents argue that the net environmental benefits of constructed wetlands, such as restoring habitat and increasing wetlands inventory, should be considered. 8 refs., 6 photos

Multiple factors influence the vegetation composition of Southeast U.S. wetlands restored in the Wetlands Reserve Program

Science.gov (United States)

Diane De Steven; Joel M. Gramling

2013-01-01

Degradation of wetlands on agricultural lands contributes to the loss of local or regional vegetation diversity. The U.S. Department of Agriculture’s Wetlands Reserve Program (WRP) funds the restoration of degraded wetlands on private ‘working lands’, but these WRP projects have not been studied in the Southeast United States. Wetland hydrogeomorphic type influences...

Industry and forest wetlands: Cooperative research initiatives

International Nuclear Information System (INIS)

Shepard, J.P.; Lucier, A.A.; Haines, L.W.

1993-01-01

In 1989 the forest products industry responded to a challenge of the National Wetlands Policy Forum to initiate a cooperative research program on forest wetlands management organized through the National Council of the Paper Industry for Air and Stream Improvement (NCASI). The objective is to determine how forest landowners can manage wetlands for timber production while protecting other wetland functions such as flood storage, water purification, and food chain/wildlife habitat support. Studies supported by the NCASI in 9 states are summarized. Technical support on wetland regulatory issues to member companies is part of the research program. Since guidelines for recognizing wetlands for regulatory proposed have changed frequently, the NCASI has recommend an explicit link between wetland delineation and a classification system that considers difference among wetland types in vegetation, soils, hydrology, appearance, landscape position, and other factors. 16 refs

Global warming and prairie wetlands

International Nuclear Information System (INIS)

Poiani, K.A.; Johnson, W.C.

1991-01-01

In this article, the authors discuss current understanding and projections of global warming; review wetland vegetation dynamics to establish the strong relationship among climate, wetland hydrology, vegetation patterns and waterfowl habitat; discuss the potential effects of a greenhouse warming on these relationships; and illustrate the potential effects of climate change on wetland habitat by using a simulation model

Wetland soils, hydrology and geomorphology

Science.gov (United States)

C. Rhett Jackson; James A. Thompson; Randall K. Kolka

2014-01-01

The hydrology, soils, and watershed processes of a wetland all interact with vegetation and animals over time to create the dynamic physical template upon which a wetland's ecosystem is based (Fig. 2.1). With respect to many ecosystem processes, the physical factors defining a wetland environment at any particular time are often treated as independent variables,...

Ecosystem function in oil sands wetlands : rates of detrital decomposition, moss growth, and microbial respiration in oilsands wetlands

Energy Technology Data Exchange (ETDEWEB)

Wytrykush, C. [Windsor Univ., ON (Canada); Hornung, J. [Petro-Canada, Calgary, AB (Canada)

2007-07-01

A study was conducted in which leaf litter breakdown and biomass accrual in 31 reference and oilsands affected (OSPM) wetlands in Northeastern Alberta was examined. The purpose was to determine how the decomposition of dead plant matter controls the primary productivity in wetlands. The data collected from this study will provide information about carbon flow and dynamics in oilsands affected wetlands. The study involved the investigation of wetlands that contrasted in water origin (OSPM vs. reference), sediment origin (OSPM vs. natural), sediment organic content and age. Mesh bags containing 5 g of dried Typha (cattail) or 20 g of damp moss were placed into 31 wetlands in order to monitor the rate at which biomass was lost to decomposition, as measured by changes in dry mass. After 1 year, moss growth was found to be greatest in younger wetlands with natural sediments. Cattail decomposition was found to be slower in wetlands containing OSPM water than that in reference wetlands. Preliminary analysis of respiration rates of biota associated with decomposing cattail indicate that the amount of oxygen consumed is not affected by wetland water source, sediment source, level of initial sediment organic content, or age.

GlobWetland Africa: Implementing Sustainable Earth Observation Based Wetland Monitoring Capacity in Africa and Beyond

DEFF Research Database (Denmark)

Tottrup, Christian; Riffler, Michael; Wang, Tiejun

and decision support, [iii] receive a freely available, open, flexible and modifiable framework for easy establishment of new wetland observatories, for easy integration in existing observatory infrastructures and for easy adaptation to new requirements, e.g. changes in management processes.......Lack of data, appropriate information and challenges in human and institutional capacity put a serious constraint on effective monitoring and management of wetlands in Africa. Conventional data are often lacking in time or space, of poor quality or available at locations that are not necessarily...... for the conservation, wiseuse and effective management of wetlands in Africa and to provide African stakeholders with the necessary EO methods and tools to better fulfil their commitments and obligations towards the Ramsar Convention on Wetlands. The main objective of GlobWetland Africa (GW-A) is to provide the major...

National Wetland Condition Assessment 2011: A Collaborative Survey of the Nation's Wetlands

Science.gov (United States)

The National Wetland Condition Assessment 2011: A Collaborative Survey presents the results of an unprecedented assessment of the nation’s wetlands. This report is part of the National Aquatic Resource Surveys, a series of statistically based surveys designed to provide the publi...

Groundwater recharge in the tropics: a pan-African analysis of observations

Science.gov (United States)

Taylor, R. G.

2015-12-01

Groundwater is a vital source of freshwater in sub-Saharan Africa where rainfall and river discharge are unreliable and per-capita reservoir storage is among the lowest in the world. Groundwater is widely considered a distributed, low-cost and climate-resilient option to meet rapidly growing freshwater demand and alleviate endemic poverty by expanding access to safe water and improving food security through irrigation. Recent research indicates that groundwater storage in Africa is about 100 times greater than annual river discharge yet major uncertainties remain in the magnitude and nature of replenishment through recharge as well as the impacts of land-use and climate change. Here, we present newly compiled, multi-decadal observations of groundwater levels from 5 countries (Benin, Burkina Faso, Niger, Tanzania, Uganda) and paired measurements of stable isotope ratios of O and H in precipitation and groundwater at 11 locations. These data reveal both a distinct bias in groundwater recharge to intensive rainfall and rapid recharge pathways (e.g. focused, macropore flow) that are inconsistent with conventional recharge models assuming pore-matrix flow defined by the Darcy-Richards equation. Further the records highlight the substantial influence of land-use change (e.g. conversion of natural, perennial cover to croplands) on groundwater recharge. The compiled observations also provide, for the first time, a pan-African baseline to evaluate the performance of large-scale hydrological models and Land-Surface Models incorporating groundwater in this region. Our results suggest that the intensification of precipitation brought about by global warming favours groundwater replenishment in sub-Saharan Africa. As such, groundwater may prove to be a climate-resilient source of freshwater in the tropics, enabling adaptive strategies such as groundwater-fed irrigation and sustaining domestic and industrial water supplies.

Applicability Assessment of Uavsar Data in Wetland Monitoring: a Case Study of Louisiana Wetland

Science.gov (United States)

Zhao, J.; Niu, Y.; Lu, Z.; Yang, J.; Li, P.; Liu, W.

2018-04-01

Wetlands are highly productive and support a wide variety of ecosystem goods and services. Monitoring wetland is essential and potential. Because of the repeat-pass nature of satellite orbit and airborne, time-series of remote sensing data can be obtained to monitor wetland. UAVSAR is a NASA L-band synthetic aperture radar (SAR) sensor compact pod-mounted polarimetric instrument for interferometric repeat-track observations. Moreover, UAVSAR images can accurately map crustal deformations associated with natural hazards, such as volcanoes and earthquakes. And its polarization agility facilitates terrain and land-use classification and change detection. In this paper, the multi-temporal UAVSAR data are applied for monitoring the wetland change. Using the multi-temporal polarimetric SAR (PolSAR) data, the change detection maps are obtained by unsupervised and supervised method. And the coherence is extracted from the interfometric SAR (InSAR) data to verify the accuracy of change detection map. The experimental results show that the multi-temporal UAVSAR data is fit for wetland monitor.

Helium evidences for mantle degassing in the groundwater of Madeira Island – Portugal

International Nuclear Information System (INIS)

Amaral, Helena I.F.; Midões, Carla; Kipfer, Rolf

2017-01-01

The Madeira Island is fed by an active hotspot, but there are no evidences of current volcanism and geothermal activity or, of a heat source at depth, which probably justifies why only low temperature and low TDS groundwater is found in Madeira. Nonetheless, Madeira is a relatively young island (≤7 Ma old), and a connection to the upper mantle through geological conduits, is likely to occur. To investigate whether such a connection exists, noble gases and stable isotopes were, so far as we know, for the first time measured in groundwater samples of the main (basal) aquifer of Madeira Is. Groundwater is the main supply of drinking water in Madeira Is., and the hydrogeology of the island has been well characterized in previous studies. In this study, groundwater was generically divided into ‘cold’ waters (<20 °C, near the coast) and ‘warm’ waters (20–25 °C, central part of the island). This division was based on field temperature, water chemistry and stable isotopic composition. Four ‘hot’ waters (23–25 °C) showed partly distinct characteristics. A bubbling spring was also sampled. Very low tritium values indicate groundwater recharged recently and/or mix with free-tritium waters. Groundwater is fed by rain recharged during autumn as indicated by δ"1"8O and δ"2H signatures. During infiltration, the waters dissolved soil CO_2 that according to the back-calculated δ"1"3C-CO_2 compositions corresponds mainly to CO_2 of biogenic origin. Nonetheless, a mantle CO_2 component cannot be excluded from samples from the inner part of the island. The noblegas helium was the sole tracer indicating a deep gas contribution to the groundwater. A strong mantle signal was detected in the ‘hot’ and bubbling waters, as indicated by their He-Ra values of 8 (being Ra the atmospheric "3He/"4He ratio), typical of the MORB. Thus, even if the last volcanic eruption occurred ca. 0,006 Ma, degassing of the upper-mantle was detected in the shallow cold waters of

The impact of ornithogenic inputs on phosphorous transport from altered wetland soils to waterways in East Mediterranean ecosystem.

Science.gov (United States)

Litaor, M Iggy; Reichmann, O; Dente, E; Naftaly, A; Shenker, M

2014-03-01

Large flocks of Eurasian crane (Grus grus, >35,000) have begun wintering in an altered wetland agro-ecosystem located in Northern Israel, a phenomenon that attracts more than 400,000 eco-tourists a year. A 100-ha plot has been used to feed the cranes in order to protect nearby fields. The objective of this study was to evaluate the influence of this bird's feeding practice on the P status of the altered wetland soils and waterways. We installed a series of wells at two depths (40 and 90 cm) between two major waterways in the feeding area and monitored the hydraulic heads and collected groundwater samples for elemental analyses. We collected six soil cores and four sediment samples from the waterways and conducted sequential P extraction. We found significant increase in groundwater soluble reactive P (SRP) (>0.5 mg l(-1)) compared with much lower concentrations (~0.06 mg l(-1)) collected in the period prior to the feeding. We found significant decrease in Fe((II)), Ca, and SO4 concentrations in the shallow groundwater (33, 208, and 213 mg l(-1), respectively) compared with the period prior to the feeding (47, 460, and 370 mg l(-1) respectively). An increase in the more labile P fraction was observed in soils and sediments compared with the period before the feeding. The P input by bird excrement to the feeding area was estimated around 700 kg P per season, while P removal by plant harvesting was estimated around 640 kg Pyr(-1). This finding supports the current eco-tourism practices in the middle of intensive farming area, suggesting little impact on waterways. Copyright © 2013 Elsevier B.V. All rights reserved.

Water subsidies from mountains to deserts: their role in sustaining groundwater-fed oases in a sandy landscape.

Science.gov (United States)

Jobbágy, E G; Nosetto, M D; Villagra, P E; Jackson, R B

2011-04-01

In arid regions throughout the world, shallow phreatic aquifers feed natural oases of much higher productivity than would be expected solely from local rainfall. In South America, the presence of well-developed Prosopis flexuosa woodlands in the Monte Desert region east of the Andes has puzzled scientists for decades. Today these woodlands provide crucial subsistence to local populations, including descendants of the indigenous Huarpes. We explore the vulnerability and importance of phreatic groundwater for the productivity of the region, comparing the contributions of local rainfall to that of remote mountain recharge that is increasingly being diverted for irrigated agriculture before it reaches the desert. We combined deep soil coring, plant measurements, direct water-table observations, and stable-isotopic analyses (2H and 18O) of meteoric, surface, and ground waters at three study sites across the region, comparing woodland stands, bare dunes, and surrounding shrublands. The isotopic composition of phreatic groundwaters (delta2H: -137 per thousand +/- 5 per thousand) closely matched the signature of water brought to the region by the Mendoza River (-137 per thousand +/- 6 per thousand), suggestin that mountain-river infiltration rather than in situ rainfall deep drainage (-39 per thousand +/- 19 per thousand) was the dominant mechanism of recharge. Similarly, chloride mass balances determined from deep soil profiles (> 6 m) suggested very low recharge rates. Vegetation in woodland ecosystems, where significant groundwater discharge losses, likely >100 mm/yr occurred, relied on regionally derived groundwater located from 6.5 to 9.5 m underground. At these locations, daily water-table fluctuations of 10 mm, and stable-isotopic measurements of plant water, indicated groundwater uptake rates of 200-300 mm/yr. Regional scaling suggests that groundwater evapotranspiration reaches 18-42 mm/yr across the landscape, accounting for 7 17% of the Mendoza River flow

Modelling Hydrological Processes in Created Freshwater Wetlands:an Integrated System Approach%人工淡水湿地的水文过程模拟:综合系统法(摘要)

Institute of Scientific and Technical Information of China (English)

张立; 威廉·杰·米奇

2006-01-01

This study investigates hydrologic processes of four different flow-through created freshwater wetlands in Ohio, USA, by use of several versions of a simple daily mass-balance water budget model.The model includes surface inflows and outflows, precipitation, evapotranspiration, and groundwater seepage. We calibrated the daily water budget for two experimental wetlands that had pumped inflow during 1999 and validated it during 2000 - 2002 on the same basins. The coefficient of prediction efficiency is 0.70 and the modelled hydroperiod followed observed water depths during the calibration period well. The average retention time in the calibration year 1999 was 4.4 - 4.6 days. The model was applied to a 3-ha created riparian wetland that receives river flooding. Results illustrated that this wetland has developed a hydroperiod with more than sufficient flooding to ensure that it will meet the hydrologic criteria of a formal jurisdictional wetland definition in the USA. Water budget predictions for a stormwater wetland provided useful design information for hydroperiod and hydrologic dynamics prior to the construction of that system. The model was simulated for average, dry, and wet years. An integrated systems approach was developed using a STELLA 7.0 with its capabilities of dynamicinterface level control (e. g. buttons and switches) features.

French vertical flow constructed wetlands: a need of a better understanding of the role of the deposit layer.

Science.gov (United States)

Molle, Pascal

2014-01-01

French vertical flow constructed wetlands, treating directly raw wastewater, have become the main systems implemented for communities under 2,000 population equivalent in France. Like in sludge drying reed beds, an organic deposit layer is formed over time at the top surface of the filter. This deposit layer is a key factor in the performance of the system as it impacts hydraulic, gas transfers, filtration efficiency and water retention time. The paper discusses the role of this deposit layer on the hydraulic and biological behaviour of the system. It presents results from different studies to highlight the positive role of the layer but, as well, the difficulties in modelling this organic layer. As hydraulic, oxygen transfers, and biological activity are interlinked and impacted by the deposit layer, it seems essential to focus on its role (and its quantification) to find new developments of vertical flow constructed wetlands fed with raw wastewater.

Solar-based groundwater pumping for irrigation: Sustainability, policies, and limitations

International Nuclear Information System (INIS)

Closas, Alvar; Rap, Edwin

2017-01-01

The increasing demand for solar-powered irrigation systems in agriculture has spurred a race for projects as it potentially offers a cost-effective and sustainable energy solution to off-grid farmers while helping food production and sustaining livelihoods. As a result, countries such as Morocco and Yemen have been promoting this technology for farmers and national plans with variable finance and subsidy schemes like in India have been put forward. By focusing on the application of solar photovoltaic (PV) pumping systems in groundwater-fed agriculture, this paper highlights the need to further study the impacts, opportunities and limitations of this technology within the Water-Energy-Food (WEF) nexus. It shows how most policies and projects promoting solar-based groundwater pumping for irrigation through subsidies and other incentives overlook the real financial and economic costs of this solution as well as the availability of water resources and the potential negative impacts on the environment caused by groundwater over-abstraction. There is a need to monitor groundwater abstraction, targeting subsidies and improving the knowledge and monitoring of resource use. Failing to address these issues could lead to further groundwater depletion, which could threaten the sustainability of this technology and dependent livelihoods in the future. - Highlights: • Solar pumping projects require assessing environmental and financial sustainability. • Subsidies for solar pumping need to be tied to groundwater pumping regulations. • Solar irrigation projects need to consider groundwater availability and depletion. • Data and monitoring are needed to improve water resource impact assessments.

Wetland Mitigation Monitoring at the Fernald Preserve - 13200

Energy Technology Data Exchange (ETDEWEB)

Powell, Jane [Fernald Preserve Site Manager, DOE Office of Legacy Management, Harrison, Ohio (United States); Bien, Stephanie; Decker, Ashlee; Homer, John [Environmental Scientist, S.M. Stoller Corporation, Harrison, Ohio (United States); Wulker, Brian [Intern, S.M. Stoller Corporation, Harrison, Ohio (United States)

2013-07-01

The U.S. Department of Energy is responsible for 7.2 hectares (17.8 acres) of mitigation wetland at the Fernald Preserve, Ohio. Remedial activities affected the wetlands, and mitigation plans were incorporated into site-wide ecological restoration planning. In 2008, the Fernald Natural Resource Trustees developed a comprehensive wetland mitigation monitoring approach to evaluate whether compensatory mitigation requirements have been met. The Fernald Preserve Wetland Mitigation Monitoring Plan provided a guideline for wetland evaluations. The Ohio Environmental Protection Agency (Ohio EPA) wetland mitigation monitoring protocols were adopted as the means for compensatory wetland evaluation. Design, hydrologic regime, vegetation, wildlife, and biogeochemistry were evaluated from 2009 to 2011. Evaluations showed mixed results when compared to the Ohio EPA performance standards. Results of vegetation monitoring varied, with the best results occurring in wetlands adjacent to forested areas. Amphibians, particularly ambystomatid salamanders, were observed in two areas adjacent to forested areas. Not all wetlands met vegetation performance standards and amphibian biodiversity metrics. However, Fernald mitigation wetlands showed substantially higher ratings compared to other mitigated wetlands in Ohio. Also, soil sampling results remain consistent with other Ohio mitigated wetlands. The performance standards are not intended to be 'pass/fail' criteria; rather, they are reference points for use in making decisions regarding future monitoring and maintenance. The Trustees approved the Fernald Preserve Wetland Mitigation Monitoring Report with the provision that long-term monitoring of the wetlands continues at the Fernald Preserve. (authors)

Wetland Mitigation Monitoring at the Fernald Preserve - 13200

International Nuclear Information System (INIS)

Powell, Jane; Bien, Stephanie; Decker, Ashlee; Homer, John; Wulker, Brian

2013-01-01

The U.S. Department of Energy is responsible for 7.2 hectares (17.8 acres) of mitigation wetland at the Fernald Preserve, Ohio. Remedial activities affected the wetlands, and mitigation plans were incorporated into site-wide ecological restoration planning. In 2008, the Fernald Natural Resource Trustees developed a comprehensive wetland mitigation monitoring approach to evaluate whether compensatory mitigation requirements have been met. The Fernald Preserve Wetland Mitigation Monitoring Plan provided a guideline for wetland evaluations. The Ohio Environmental Protection Agency (Ohio EPA) wetland mitigation monitoring protocols were adopted as the means for compensatory wetland evaluation. Design, hydrologic regime, vegetation, wildlife, and biogeochemistry were evaluated from 2009 to 2011. Evaluations showed mixed results when compared to the Ohio EPA performance standards. Results of vegetation monitoring varied, with the best results occurring in wetlands adjacent to forested areas. Amphibians, particularly ambystomatid salamanders, were observed in two areas adjacent to forested areas. Not all wetlands met vegetation performance standards and amphibian biodiversity metrics. However, Fernald mitigation wetlands showed substantially higher ratings compared to other mitigated wetlands in Ohio. Also, soil sampling results remain consistent with other Ohio mitigated wetlands. The performance standards are not intended to be 'pass/fail' criteria; rather, they are reference points for use in making decisions regarding future monitoring and maintenance. The Trustees approved the Fernald Preserve Wetland Mitigation Monitoring Report with the provision that long-term monitoring of the wetlands continues at the Fernald Preserve. (authors)

Why are wetlands important?

Science.gov (United States)

Wetlands are among the most productive ecosystems in the world, comparable to rain forests and coral reefs. An immense variety of species of microbes, plants, insects, amphibians, reptiles, birds, fish, and mammals can be part of a wetland ecosystem.

Minimal groundwater leakage restricts salinity in a hydrologically terminal basin of northwest Australia

Science.gov (United States)

Skrzypek, Grzegorz; Dogramaci, Shawan; Rouillard, Alexandra; Grierson, Pauline

2016-04-01

The Fortescue Marsh (FM) is one of the largest wetlands of arid northwest Australia (~1200 km2) and is thought to act as a terminal basin for the Upper Fortescue River catchment. Unlike the playa lake systems that predominate in most arid regions, where salinity is driven by inflow and evaporation of groundwater, the hydrological regime of the FM is driven by inundation from irregular cyclonic events [1]. Surface water of the FM is fresh to brackish and the salinity of the deepest groundwater (80 m b.g.l.) does not exceed 160 g/L; salt efflorescences are rarely present on the surface [2]. In this study, we tested the hypothesis that persistent but low rates of groundwater outflow have restricted the accumulation of salt in the FM over time. Using hydrological, hydrochemical data and dimensionless time evaporation modelling along with the water and salt budget, we calculated the time and the annual groundwater discharge volume that would be required to achieve and maintain the range of salinity levels observed in the Marsh. Groundwater outflow from alluvial and colluvial aquifers to the Lower Fortescue catchment is limited by an extremely low hydraulic gradient of 0.001 and is restricted to a relatively small 'alluvial window' of 0.35 km2 because of the elevation of the basement bedrock at the Marsh outflow. We show that if the Marsh was 100% "leakage free" i.e., a true terminal basin for the Upper Fortescue Catchment, the basin water would have achieved salt saturation after ~45 ka. This is not the case and only a very small outflow of saline groundwater of water volume) is needed to maintain the current salinity conditions. The minimum time required to develop the current hydrochemical composition of the water in the Marsh and the steady-state conditions for salt concentration is between 58 and 164 ka. This is a minimum age of the Marsh but it can be much older as nearly steady-state conditions could be maintained infinitely. Our approach using a combined water

Evidence of terrestrial discharge of deep groundwater on the Canadian Shield from helium in soil gases

International Nuclear Information System (INIS)

Gascoyne, M.; Sheppard, M.I.

1993-01-01

Assessment of the impact of deep geological disposal of nuclear fuel wastes at a site in the Canadian Shield requires knowledge of the location and size of areas of discharge of deep groundwater from the vicinity of the underground disposal vault. A strong He anomaly has been detected in soil gases in a 10 X 10 m area of wetland on the banks of Boggy Creek, near Lac du Bonnet, Manitoba. The area has He concentrations in near-surface soils as high as 360 nL·L -1 and is assumed to indicate discharge of He-rich groundwater through a permeable subsurface bedrock fracture. Elevated Cl - concentrations in groundwater and its use as a open-quotes deer lickclose quotes support this interpretation. A He flux density of ∼ 2.1 L·m -2 ·a -1 is determined from a depth profile of He concentrations at one location in the site. A total He flux of 270 L·a -1 is determined for the entire site, which corresponds to a deep groundwater discharge of about 26 000 L·a -1 . This estimate is comparable with He fluxes and calculated groundwater discharges for two other lake-bottom locations on the Canadian Shield. 26 refs., 6 figs., 1 tab

Tool for assessment of process importance at the groundwater/surface water interface.

Science.gov (United States)

Palakodeti, Ravi C; LeBoeuf, Eugene J; Clarke, James H

2009-10-01

The groundwater/surface water interface (GWSWI) represents an important transition zone between groundwater and surface water environments that potentially changes the nature and flux of contaminants exchanged between the two systems. Identifying dominant and rate-limiting contaminant transformation processes is critically important for estimating contaminant fluxes and compositional changes across the GWSWI. A new, user-friendly, spreadsheet- and Visual Basic-based analytical screening tool that assists in evaluating the dominance of controlling kinetic processes across the GWSWI is presented. Based on contaminant properties, first-order processes that may play a significant role in solute transport/transformation are evaluated in terms of a ratio of process importance (P(i)) that relates the process rate to the rate of fluid transfer. Besides possessing several useful compilations of contaminant and process data, the screening tool also includes 1-D analytical models that assist users in evaluating contaminant transport across the GWSWI. The tool currently applies to 29 organics and 10 inorganics of interest within the context of the GWSWI. Application of the new screening tool is demonstrated through an evaluation of natural attenuation at a site with trichloroethylene and 1,1,2,2-tetrachloroethane contaminated groundwater discharging into wetlands.

Geospatial Modelling for Micro Zonation of Groundwater Regime in Western Assam, India

Science.gov (United States)

Singh, R. P.

2016-12-01

Water, most precious natural resource on earth, is vital to sustain the natural system and human civilisation on the earth. The Assam state located in north-eastern part of India has a relatively good source of ground water due to their geographic and physiographic location but there is problem deterioration of groundwater quality causing major health problem in the area. In this study, I tried a integrated study of remote sensing and GIS and chemical analysis of groundwater samples to throw a light over groundwater regime and provides information for decision makers to make sustainable water resource management. The geospatial modelling performed by integrating hydrogeomorphic features. Geomorphology, lineament, Drainage, Landuse/landcover layer were generated through visual interpretation on satellite image (LISS III) based on tone, texture, shape, size, and arrangement of the features. Slope layer was prepared by using SRTM DEM data set .The LULC of the area were categories in to 6 classes of Agricultural field, Forest area ,River, Settlement , Tree-clad area and Wetlands. The geospatial modelling performed through weightage and rank method in GIS, depending on the influence of the features on ground water regime. To Assess the ground water quality of the area 45 groundwater samples have been collected from the field and chemical analysis performed through the standard method in the laboratory. The overall assessment of the ground water quality of the area analyse through Water Quality Index and found that about 70% samples are not potable for drinking purposes due to higher concentration Arsenic, Fluoride and Iron. It appears that, source of all these pollutants geologically and geomorphologically derived. Interpolated layer of Water Quality Index and geospatial modelled Groundwater potential layer provides a holistic view of groundwater scenario and provide direction for better planning and groundwater resource management. Study will be discussed in details

Methodological application so as to obtain digital elevation models DEM in wetland areas

International Nuclear Information System (INIS)

Quintero, Deiby A; Montoya V, Diana M; Betancur, Teresita

2009-01-01

In order to understand hydrological systems and the description of flow processes that occur among its components it is essential to have a physiographic description that morphometric and relief characteristics. When local studies are performed, the basic cartography available, in the best case 1:25,000 scale, tends not to obey the needs required to represent the water dynamics that characterize the interactions between streams, aquifers and lenticular water bodies in flat zones particularly in those where there are wetlands localized in ancient F100D plains of rivers. A lack of financial resources is the principal obstacle to acquiring; information that is current and sufficient for the scale of the project. Geomorphologic conditions of flat relief zones are a good alternative for the construction of the new data. Using the basic cartography available and the new data, it is possible to obtain DEMs that are improved and consistent with the dynamics of surface and groundwater flows in the hydrological system. To accomplish this one must use spatial modeling tools coupled with Geographic Information System - GIS. This article present a methodological application for the region surrounding the catchment of wetland Cienaga Colombia in the Bajo Cauca region of Antioquia.

A hydrological and geochemical survey of the groundwater resource of Favignana Island

International Nuclear Information System (INIS)

Grillini, Marcello; De Cassan, Maurizio; Proposito, Marco

2015-01-01

Small islands suffer water shortage, and tourist pressure makes it even worse: Favignana island is the site that best represents such conditions, due to the contrast between the intense anthropization and the harsh nature of the terrains. The ENEA study hypothesized a solution in identifying the best areas where groundwater is abundant and presents the best conditions to take water samples for anthropic use. With hydrological measurements and chemical analyses, an area theoretically interesting has been identified in the eastern sector, where groundwater is better in quality and just a few meters deep below the ground. Westwards, instead, it is at a lower depth and saltier, due to its more intense contamination with seawater. Yet the amount of available groundwater is everywhere so poor that more intense water sampling is not recommended: people have always been living in good balance with nature, and they know how to manage the island's groundwater resource, fed by rare precipitations, as a supplement to the drinking water supply coming from Trapani [it

Spectral model for long-term computation of thermodynamics and potential evaporation in shallow wetlands

Science.gov (United States)

de la Fuente, Alberto; Meruane, Carolina

2017-09-01

Altiplanic wetlands are unique ecosystems located in the elevated plateaus of Chile, Argentina, Peru, and Bolivia. These ecosystems are under threat due to changes in land use, groundwater extractions, and climate change that will modify the water balance through changes in precipitation and evaporation rates. Long-term prediction of the fate of aquatic ecosystems imposes computational constraints that make finding a solution impossible in some cases. In this article, we present a spectral model for long-term simulations of the thermodynamics of shallow wetlands in the limit case when the water depth tends to zero. This spectral model solves for water and sediment temperature, as well as heat, momentum, and mass exchanged with the atmosphere. The parameters of the model (water depth, thermal properties of the sediments, and surface albedo) and the atmospheric downscaling were calibrated using the MODIS product of the land surface temperature. Moreover, the performance of the daily evaporation rates predicted by the model was evaluated against daily pan evaporation data measured between 1964 and 2012. The spectral model was able to correctly represent both seasonal fluctuation and climatic trends observed in daily evaporation rates. It is concluded that the spectral model presented in this article is a suitable tool for assessing the global climate change effects on shallow wetlands whose thermodynamics is forced by heat exchanges with the atmosphere and modulated by the heat-reservoir role of the sediments.

1996 monitoring report for the Gunnison, Colorado, wetlands mitigation plan

International Nuclear Information System (INIS)

1996-12-01

The US Department of Energy (DOE) administers the Uranium Mill Tailings Remedial Action (UMTRA) Project to clean up uranium mill tailings and other surface contamination at 24 abandoned uranium mill sites in 10 states. One of these abandoned mill sites was near the town of Gunnison, Colorado. Surface remediation was completed at the Gunnison site in December 1995. Remedial action resulted in the elimination of 4.3 acres of wetlands and mitigation of this loss is through the enhancement of 17.8 acres of riparian plant communities in six spring-fed areas on US Bureau of Land Management mitigation sites. A five-year monitoring program was then implemented to document the response of vegetation and wildlife to the exclusion of livestock. This report provides the results of the third year of the monitoring program

Description of the Wetlands Research Programme

CSIR Research Space (South Africa)

Walmsley, RD

1988-01-01

Full Text Available This report presents a rationale to the development of a multidisciplinary South African Wetland Research Programme. A definition of what is meant by the term wetland is given along with a general description of what types of wetland occur in South...

Modelling groundwater discharge areas using only digital elevation models as input data

Energy Technology Data Exchange (ETDEWEB)

Brydsten, Lars [Umeaa Univ. (Sweden). Dept. of Biology and Environmental Science

2006-10-15

Advanced geohydrological models require data on topography, soil distribution in three dimensions, vegetation, land use, bedrock fracture zones. To model present geohydrological conditions, these factors can be gathered with different techniques. If a future geohydrological condition is modelled in an area with positive shore displacement (say 5,000 or 10,000 years), some of these factors can be difficult to measure. This could include the development of wetlands and the filling of lakes. If the goal of the model is to predict distribution of groundwater recharge and discharge areas in the landscape, the most important factor is topography. The question is how much can topography alone explain the distribution of geohydrological objects in the landscape. A simplified description of the distribution of geohydrological objects in the landscape is that groundwater recharge areas occur at local elevation curvatures and discharge occurs in lakes, brooks, and low situated slopes. Areas in-between these make up discharge areas during wet periods and recharge areas during dry periods. A model that could predict this pattern only using topography data needs to be able to predict high ridges and future lakes and brooks. This study uses GIS software with four different functions using digital elevation models as input data, geomorphometrical parameters to predict landscape ridges, basin fill for predicting lakes, flow accumulations for predicting future waterways, and topographical wetness indexes for dividing in-between areas based on degree of wetness. An area between the village of and Forsmarks' Nuclear Power Plant has been used to calibrate the model. The area is within the SKB 10-metre Elevation Model (DEM) and has a high-resolution orienteering map for wetlands. Wetlands are assumed to be groundwater discharge areas. Five hundred points were randomly distributed across the wetlands. These are potential discharge points. Model parameters were chosen with the

Urban wetlands: restoration or designed rehabilitation?

Directory of Open Access Journals (Sweden)

Beth Ravit

2017-05-01

Full Text Available The continuing loss of urban wetlands due to an expanding human population and urban development pressures makes restoration or creation of urban wetlands a high priority. However, urban wetland restorations are particularly challenging due to altered hydrologic patterns, a high proportion of impervious surface and stormwater runoff, degraded urban soils, historic contamination, and competitive pressure from non-native species. Urban wetland projects must also consider human-desired socio-economic benefits. We argue that using current wetland restoration approaches and existing regulatory “success” criteria, such as meeting restoration targets for vegetation structure based on reference sites in non-urban locations, will result in “failed” urban restorations. Using three wetland Case Studies in highly urbanized locations, we describe geophysical tools, stormwater management methods, and design approaches useful in addressing urban challenges and in supporting “successful” urban rehabilitation outcomes. We suggest that in human-dominated landscapes, the current paradigm of “restoration” to a previous state must shift to a paradigm of “rehabilitation”, which prioritizes wetland functions and values rather than vegetation structure in order to provide increased ecological benefits and much needed urban open space amenities.

The study of Phosphorus distribution at Putrajaya Wetland

Science.gov (United States)

Mubin Zahari, Nazirul; Malek, Nur Farzana Fasiha Abdul; Fai, Chow Ming; Humaira Haron, Siti; Hafiz Zawawi, Mohd; Nazmi Ismail, Iszmir; Mohamad, Daud; Syamsir, Agusril; Sidek, Lariyah Mohd; Zakwan Ramli, Mohd; Ismail, Norfariza; Zubir Sapian, Ahmad; Noordin, Normaliza; Rahaman, Nurliyana Abdul; Muhamad, Yahzam; Mat Saman, Jarina

2018-04-01

This study is concerning phosphorus distribution in Putrajaya Wetland. Phosphorus is one of the important component in nutrients for living things be it aquatic or non – aquatic organisms. Total phosphorus (TP) results will give some information on the trophic status of surface water in water bodies. The focus of this study is to determine the total phosphorus concentration in Putrajaya Wetland which is in the inlet of the wetland then outlet of the wetland (Central Wetland Lake). The water sample is taken from Putrajaya Wetland and the test was conducted in the laboratory. The result from this study shows the results for total phosphorus according to month, sampling station and cells. Lowest total phosphate at the Central Wetland compare with all the wetland arms cells.

Development of an indicator to monitor mediterranean wetlands.

Science.gov (United States)

Sanchez, Antonio; Abdul Malak, Dania; Guelmami, Anis; Perennou, Christian

2015-01-01

Wetlands are sensitive ecosystems that are increasingly subjected to threats from anthropogenic factors. In the last decades, coastal Mediterranean wetlands have been suffering considerable pressures from land use change, intensification of urban growth, increasing tourism infrastructure and intensification of agricultural practices. Remote sensing (RS) and Geographic Information Systems (GIS) techniques are efficient tools that can support monitoring Mediterranean coastal wetlands on large scales and over long periods of time. The study aims at developing a wetland indicator to support monitoring Mediterranean coastal wetlands using these techniques. The indicator makes use of multi-temporal Landsat images, land use reference layers, a 50m numerical model of the territory (NMT) and Corine Land Cover (CLC) for the identification and mapping of wetlands. The approach combines supervised image classification techniques making use of vegetation indices and decision tree analysis to identify the surface covered by wetlands at a given date. A validation process is put in place to compare outcomes with existing local wetland inventories to check the results reliability. The indicator´s results demonstrate an improvement in the level of precision of change detection methods achieved by traditional tools providing reliability up to 95% in main wetland areas. The results confirm that the use of RS techniques improves the precision of wetland detection compared to the use of CLC for wetland monitoring and stress the strong relation between the level of wetland detection and the nature of the wetland areas and the monitoring scale considered.

Recreating wetland ecosystems in an oil sands disturbed landscape : Suncor consolidated-tailings demonstration wetlands

Energy Technology Data Exchange (ETDEWEB)

Daly, C. [Suncor Energy, Fort McMurray, AB (Canada). Aquatic Reclamation Research; Tedder, W.; Marlowe, P. [Golder Associates Ltd., Calgary, AB (Canada). Oil Sands Div.

2009-10-01

Open pit oil sands mining involves the disturbance of thin overburden covers of Boreal forest lands that must be returned to equivalent land capability after mining activities have ceased. Before mining starts, any wetlands are drained, timber is harvested, and peat, topsoils and subsoils are stockpiled for later use. This article discussed wetland reclamation activities conducted by Suncor Energy at its open pit mining operations. Research facilities were constructed in order to determine if wetlands constructed with consolidated tailings (CT) and pond effluent water (PEW) were able to support a sustainable vegetation community. Thirty-three cat-tail plots were established at the facility as well as unplanted plots in order to determine how quickly natural establishment occurred. Shoreline plug transplants and transplants from a natural saline lake were also introduced. Within 5 years, over 23 plant species had naturally colonized the CT wetlands. However, diversity was lower in CT and PEW-constructed wetlands. It was concluded that the application of a native peat-mineral mix soil may help to increase plant diversity. 20 refs., 5 figs.

Wetlands in changed landscapes: the influence of habitat transformation on the physico-chemistry of temporary depression wetlands.

Science.gov (United States)

Bird, Matthew S; Day, Jenny A

2014-01-01

Temporary wetlands dominate the wet season landscape of temperate, semi-arid and arid regions, yet, other than their direct loss to development and agriculture, little information exists on how remaining wetlands have been altered by anthropogenic conversion of surrounding landscapes. This study investigates relationships between the extent and type of habitat transformation around temporary wetlands and their water column physico-chemical characteristics. A set of 90 isolated depression wetlands (seasonally inundated) occurring on coastal plains of the south-western Cape mediterranean-climate region of South Africa was sampled during the winter/spring wet season of 2007. Wetlands were sampled across habitat transformation gradients according to the areal cover of agriculture, urban development and alien invasive vegetation within 100 and 500 m radii of each wetland edge. We hypothesized that the principal drivers of physico-chemical conditions in these wetlands (e.g. soil properties, basin morphology) are altered by habitat transformation. Multivariate multiple regression analyses (distance-based Redundancy Analysis) indicated significant associations between wetland physico-chemistry and habitat transformation (overall transformation within 100 and 500 m, alien vegetation cover within 100 and 500 m, urban cover within 100 m); although for significant regressions the amount of variation explained was very low (range: ∼2 to ∼5.5%), relative to that explained by purely spatio-temporal factors (range: ∼35.5 to ∼43%). The nature of the relationships between each type of transformation in the landscape and individual physico-chemical variables in wetlands were further explored with univariate multiple regressions. Results suggest that conservation of relatively narrow (∼100 m) buffer strips around temporary wetlands is likely to be effective in the maintenance of natural conditions in terms of physico-chemical water quality.

Wetlands in changed landscapes: the influence of habitat transformation on the physico-chemistry of temporary depression wetlands.

Directory of Open Access Journals (Sweden)

Matthew S Bird

Full Text Available Temporary wetlands dominate the wet season landscape of temperate, semi-arid and arid regions, yet, other than their direct loss to development and agriculture, little information exists on how remaining wetlands have been altered by anthropogenic conversion of surrounding landscapes. This study investigates relationships between the extent and type of habitat transformation around temporary wetlands and their water column physico-chemical characteristics. A set of 90 isolated depression wetlands (seasonally inundated occurring on coastal plains of the south-western Cape mediterranean-climate region of South Africa was sampled during the winter/spring wet season of 2007. Wetlands were sampled across habitat transformation gradients according to the areal cover of agriculture, urban development and alien invasive vegetation within 100 and 500 m radii of each wetland edge. We hypothesized that the principal drivers of physico-chemical conditions in these wetlands (e.g. soil properties, basin morphology are altered by habitat transformation. Multivariate multiple regression analyses (distance-based Redundancy Analysis indicated significant associations between wetland physico-chemistry and habitat transformation (overall transformation within 100 and 500 m, alien vegetation cover within 100 and 500 m, urban cover within 100 m; although for significant regressions the amount of variation explained was very low (range: ∼2 to ∼5.5%, relative to that explained by purely spatio-temporal factors (range: ∼35.5 to ∼43%. The nature of the relationships between each type of transformation in the landscape and individual physico-chemical variables in wetlands were further explored with univariate multiple regressions. Results suggest that conservation of relatively narrow (∼100 m buffer strips around temporary wetlands is likely to be effective in the maintenance of natural conditions in terms of physico-chemical water quality.

Wetlands - an underestimated economic resource?

International Nuclear Information System (INIS)

Gren, I.M.; Soederqvist, T.

1996-01-01

Wetlands are producing several valuable resources like fish, potential for recreation, water cleaning etc. These resources, and methods for assigning an economic value to them, are discussed in this article. Swedish and foreign empirical studies of the economic value of wetlands are reviewed. This review shows that socioeconomic estimates of the value of wetlands risk to be misleading if the direct and indirect values are not properly accounted for. 37 refs

Pathogen and nutrient pulsing and attenuation in "accidental" urban wetland networks along the Salt River in Phoenix, AZ

Science.gov (United States)

Palta, M. M.; Grimm, N. B.

2013-12-01

Increases in available nutrients and bacteria in urban streams are at the forefront of research concerns within the ecological and medical communities, and both pollutants are expected to become more problematic under projected changes in climate. Season, discharge, instream conditions (oxygen, water velocity), and weather conditions (antecedent moisture) all may influence loading rates to and the retention capabilities of wetlands fed by urban runoff and storm flow. The aim of this research was to examine the effect of these variables on nutrient (nitrogen, phosphorus) and Escherichia coli (E. coli) loading and attenuation along flow paths in urban wetland networks along the Salt River in Phoenix, AZ. Samples were collected for one year along flowpaths through wetlands that formed below six perennially flowing outfalls. Collection took place monthly during baseflow (dry season) conditions, and before and immediately following storm events, in the summer monsoon and winter rainy seasons. Water quality was assessed at the following points: immediately downstream of the outfall, mid-wetland, and downstream of the wetland. For determination of E. coli counts, samples were plated on coliform-selective media (Chromocult) and incubated for 24 hours. Plates were then used to enumerate E. coli. For determination of nutrient concentrations, samples were filtered and frozen until they could be analyzed by ion chromatography and automated wet chemistry. During both summer and winter, total discharge into the wetlands increased during storm events. Concentrations of PO43+, NH4+, and E. coli were significantly higher following storm events than during baseflow conditions, and post-storm peaks in concentration ('pulses') were higher during the summer monsoon than in winter storms. Pulses of pollutants during storms were highest when preceded by hot, dry conditions. NO3- was high in both base and stormflow. E. coli counts and nutrient concentrations dropped along flowpaths

Assessment of ground-water contamination by coal-tar derivatives, St. Louis Park area, Minnesota

Science.gov (United States)

Hult, M.F.

1984-01-01

Operation of a coal-tar distillation and wood-preserving facility in St. Louis Park, Minnesota, during 1918-72 contaminated ground water with coal-tar derivatives and inorganic chemicals. Coal-tar derivatives entered the groundwater system through three major paths: (1) Spills and drippings that percolated to the water table, (2) surface runoff and plant process water that was discharged to wetlands south of the former plant site, and (3) movement of coal tar directly into bedrock aquifers through a multiaquifer well on the site.

Feasibility of using geothermal effluents for waterfowl wetlands

Energy Technology Data Exchange (ETDEWEB)

None

1981-09-01

This project was conducted to evaluate the feasibility of using geothermal effluents for developing and maintaining waterfowl wetlands. Information in the document pertains to a seven State area the West where geothermal resources have development potential. Information is included on physiochemical characteristics of geothermal effluents; known effects of constituents in the water on a wetland ecosystem and water quality criteria for maintaining a viable wetland; potential of sites for wetland development and disposal of effluent water from geothermal facilities; methods of disposal of effluents, including advantages of each method and associated costs; legal and institutional constraints which could affect geothermal wetland development; potential problems associated with depletion of geothermal resources and subsidence of wetland areas; potential interference (adverse and beneficial) of wetlands with ground water; special considerations for wetlands requirements including size, flows, and potential water usage; and final conclusions and recommendations for suitable sites for developing demonstration wetlands.

The effects of hydraulic works and wetlands function in the Salado-River basin (Buenos Aires, Argentina).

Science.gov (United States)

Bazzuri, M E; Gabellone, N A; Solari, L C

2018-01-26

Man-made activities exert great influences on fluvial ecosystems, with lowland rivers being substantially modified through agricultural land use and populations. The recent construction of drainage canals in the upper stretch of the Salado-River basin caused the mobilization of huge amounts of salts formerly stored in the groundwater. The main aim of this work was to analyze the effect of the discharges of those canals into the Salado-River water, under different hydrologic conditions, and the role of the wetlands and shallow lakes placed along the canals' system. Physicochemical variables were measured and water samples were taken during times of high water, mean flows, drought, and extreme drought. The environmental variables and the plankton development were related to the hydrologic regime and reached minimum values during floods because of low temperatures and dilution. Local effects on the water's ionic composition became pronounced during droughts because of groundwater input. Nutrient concentrations were mainly associated with point wastewater discharges. Conductivity, ion concentrations, total plankton biomass, and species richness increased in the Salado-River downstream site, after the canals' discharges. The artificial-drainage system definitely promotes the incorporation of salts into the Salado-River basin. In this scenario, a careful hydraulic management is needed to take into account this issue of secondary salinization that threatens the economic exploitation of the region. The wetlands present in this study acted as service environments not only helping to reduce salt, nutrient, and suspended-solid concentrations downstream but also contributing a plethora of species and plankton biomass into the Salado-River main course.

HPLC and MS/MS study of polar contaminants in a wetland adjoining a sour-gas plant

International Nuclear Information System (INIS)

Dickson, L.C.; Headley, J.V.; Peru, K.; Spiegel, K.; Gandrass, J.

1995-01-01

An analytical methodology was developed for target analyses and broad spectrum characterization of polar contaminants such as nitrogenous and organosulfur compounds in wetlands using the complementary techniques of HPLC with electrochemical (EC) detection and tandem MS with probe and electrospray ionization. Tandem MS was well suited for the identification and quantification of mixtures of polar compounds in water samples and soil extracts, while HPLC-EC provided sensitive detection of compounds transparent to MS detection and conventional methods. The usefulness of the methodology is demonstrated by studying the removal of polar contaminants from a wetland in western Canada affected by releases of hydrocarbon-rich condensate and free product from an adjoining sour-gas plant. The concern is that the mobile water-soluble polar contaminants may not be as efficiently attenuated by volatilization or adsorption processes as the more hydrophobic hydrocarbons and that some of the polar toxic compounds may break through to contaminate groundwater and surface waters. Samples of groundwater, surface water, and aqueous soil extracts were analyzed to quantify levels of polar contaminants in the presence of high concentrations of hydrocarbons. The use of water extracts reduced the background interference from hydrocarbons and other non-polar compounds that were present in the soil samples. HPLC-EC was used to quantify the target compounds that included monoethanolamine, diethanolamine and methyldiethanolamine and sulfolane-derived compounds while tandem MS was used to identify related compounds and degradation products. Influent concentrations were in the ppm range and discharge concentrations were in the ppb range

Effectiveness of a constructed wetland for acid mine drainage reclamation

International Nuclear Information System (INIS)

Grant, A.J.; Ramey, B.A.; Jarrett, L.; Hart, G.

1993-01-01

Acid mine drainage (AMD) from an abandoned coal mine in southcentral Kentucky had pH levels as low as 2.5 and iron concentrations as high as 630 mg/L. In the summer of 1992, the SCS constructed a wetland system to treat the AMD that involved use of both physical and biological treatment. The AMD was fed into three anoxic limestone beds, followed by an aeration pond, before entering a series of four cattail cells and a polishing pond. Flow of AMD was initiated in the fall of 1992, and chemical and biological monitoring were conducted throughout the winter months. Chemical analysis of the water along the flow path of the AMD during the first six months of operation indicated that the limestone beds improved the pH substantially, and that most of the metals were removed prior to the water entering the cattail cells. The effectiveness of the wetland system to improve water quality also was monitored using the cladoceran (Ceriodaphnia dubia) survival and reproduction test. Determination of toxic levels indicated a substantial improvement in water quality below the limestone beds, and a slight decrease in toxicity throughout the cattail cells. However, toxic levels stayed the same or increased in the polishing pond. Water quality monitoring will continue through the growing season of 1993 to assess the impact of plant growth on the reclamation of the AMD

Hydrologic connectivity to streams increases nitrogen and phosphorus inputs and cycling in soils of created and natural floodplain wetlands.

Science.gov (United States)

Wolf, Kristin L; Noe, Gregory B; Ahn, Changwoo

2013-07-01

Greater connectivity to stream surface water may result in greater inputs of allochthonous nutrients that could stimulate internal nitrogen (N) and phosphorus (P) cycling in natural, restored, and created riparian wetlands. This study investigated the effects of hydrologic connectivity to stream water on soil nutrient fluxes in plots ( = 20) located among four created and two natural freshwater wetlands of varying hydrology in the Piedmont physiographic province of Virginia. Surface water was slightly deeper; hydrologic inputs of sediment, sediment-N, and ammonium were greater; and soil net ammonification, N mineralization, and N turnover were greater in plots with stream water classified as their primary water source compared with plots with precipitation or groundwater as their primary water source. Soil water-filled pore space, inputs of nitrate, and soil net nitrification, P mineralization, and denitrification enzyme activity (DEA) were similar among plots. Soil ammonification, N mineralization, and N turnover rates increased with the loading rate of ammonium to the soil surface. Phosphorus mineralization and ammonification also increased with sedimentation and sediment-N loading rate. Nitrification flux and DEA were positively associated in these wetlands. In conclusion, hydrologic connectivity to stream water increased allochthonous inputs that stimulated soil N and P cycling and that likely led to greater retention of sediment and nutrients in created and natural wetlands. Our findings suggest that wetland creation and restoration projects should be designed to allow connectivity with stream water if the goal is to optimize the function of water quality improvement in a watershed. Copyright © by the American Society of Agronomy, Crop Science Society of America, and Soil Science Society of America, Inc.

7 CFR 1410.10 - Restoration of wetlands.

Science.gov (United States)

2010-01-01

... 7 Agriculture 10 2010-01-01 2010-01-01 false Restoration of wetlands. 1410.10 Section 1410.10... Restoration of wetlands. (a) An owner or operator who entered into a CRP contract on land that is suitable for restoration to wetlands or that was restored to wetlands while under such contract, may, if approved by CCC...

Unravelling aquifer-wetland interaction using CSAMT and gravity methods: the Mollina-Camorra aquifer and the Fuente de Piedra playa-lake, southern Spain

Science.gov (United States)

Pedrera, A.; Martos-Rosillo, S.; Galindo-Zaldívar, J.; Rodríguez-Rodríguez, M.; Benavente, J.; Martín-Rodríguez, J. F.; Zúñiga-López, M. I.

2016-06-01

The hydrological regime of Fuente de Piedra playa-lake (Málaga, southern Spain) has been significantly affected by the intensive exploitation of groundwater in the area. The playa-lake is situated above clays, marls, and gypsum, and under unaltered conditions received surface-subsurface runoff within the watershed as well as groundwater discharge from two carbonate aquifers. We have analyzed the structure of the main one, the Mollina-Camorra carbonate aquifer, by combining controlled source audio magnetotellurics (CSAMT), gravity prospecting, and time-domain electromagnetic (TDEM) soundings. This geophysical information, together with new structural and hydrogeological data, was gathered to develop a new conceptual hydrogeological model. This model allows the hydrological linkage of the carbonate aquifer with the playa-lake system to be established. Moreover, the intensive exploitation in the carbonate aquifer, even outside the watershed of the playa-lake, has affected the hydrological regime of the system. This multidisciplinary work demonstrates the potential of geophysical methods for understanding wetland-aquifer interaction, having important groundwater management implications.

Wetland restoration, flood pulsing, and disturbance dynamics

Science.gov (United States)

Middleton, Beth A.

1999-01-01

While it is generally accepted that flood pulsing and disturbance dynamics are critical to wetland viability, there is as yet no consensus among those responsible for wetland restoration about how best to plan for those phenomena or even whether it is really necessary to do so at all. In this groundbreaking book, Dr. Beth Middleton draws upon the latest research from around the world to build a strong case for making flood pulsing and disturbance dynamics integral to the wetland restoration planning process.While the initial chapters of the book are devoted to laying the conceptual foundations, most of the coverage is concerned with demonstrating the practical implications for wetland restoration and management of the latest ecological theory and research. It includes a fascinating case history section in which Dr. Middleton explores the restoration models used in five major North American, European, Australian, African, and Asian wetland projects, and analyzes their relative success from the perspective of flood pulsing and disturbance dynamics planning.Wetland Restoration also features a wealth of practical information useful to all those involved in wetland restoration and management, including: * A compendium of water level tolerances, seed germination, seedling recruitment, adult survival rates, and other key traits of wetland plant species * A bibliography of 1,200 articles and monographs covering all aspects of wetland restoration * A comprehensive directory of wetland restoration ftp sites worldwide * An extensive glossary of essential terms

78 FR 68719 - Floodplain Management and Protection of Wetlands

Science.gov (United States)

2013-11-15

... of wetlands in Sec. 55.2(b)(11) to cover manmade wetlands in order to ensure that wetlands built for...] RIN 2501-AD51 Floodplain Management and Protection of Wetlands AGENCY: Office of the Secretary, HUD... wetlands and floodplains. With respect to wetlands, the rule codifies existing procedures for Executive...

Groundwater flow model for the Little Plover River basin in Wisconsin’s Central Sands

Science.gov (United States)

Ken Bradbury,; Fienen, Michael N.; Kniffin, Maribeth; Jacob Krause,; Westenbroek, Stephen M.; Leaf, Andrew T.; Barlow, Paul M.

2017-01-01

The Little Plover River is a groundwater-fed stream in the sand plains region of central Wisconsin. In this region, sandy sediment deposited during or soon after the last glaciation forms an important unconfined sand and gravel aquifer. This aquifer supplies water for numerous high-capacity irrigation, municipal, and industrial wells that support a thriving agricultural industry. In recent years the addition of many new wells, combined with observed diminished flows in the Little Plover and other nearby rivers, has raised concerns about the impacts of the wells on groundwater levels and on water levels and flows in nearby lakes, streams, and wetlands. Diverse stakeholder groups, including well operators, Growers, environmentalists, local land owners, and regulatory and government officials have sought a better understanding of the local groundwater-surface water system and have a shared desire to balance the water needs of the he liagricultural, industrial, and urban users with the maintenance and protection of groundwater-dependent natural resources. To help address these issues, the Wisconsin Department of Natural Resources requested that the Wisconsin Geological and Natural History Survey and U.S. Geological Survey cooperatively develop a groundwater flow model that could be used to demonstrate the relationships among groundwater, surface water, and well withdrawals and also be a tool for testing and evaluating alternative water management strategies for the central sands region. Because of an abundance of previous studies, data availability, local interest, and existing regulatory constraints the model focuses on the Little Plover River watershed, but the modeling methodology developed during this study can apply to much of the larger central sands of Wisconsin. The Little Plover River groundwater flow model simulates three-dimensional groundwater movement in and around the Little Plover River basin under steady-state and transient conditions. This model