Estimating the ground-water contribution in wetlands using modeling and digital terrain analysis

Gerla, Philip J.

doi:10.1007/bf03161771

Cited by 16 publications

(10 citation statements)

References 18 publications

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“…Riparian buffers that seem well positioned according to surface topography can be ineffective when subsurface flow goes around the buffer or deep beneath the biologically active soils of the buffer zone (Denver 1991, Altman and Parizek 1995, Speiran 2010. Methods for quantifying key constraints on subsurface flow (e.g., Gerla 1999, Baker et al 2003, Kellogg et al 2008) could be incorporated to improve model results. Even without such improvements, we did observe strong and statistically significant buffer effects in the Coastal Plain and Piedmont study watersheds, which confirms that our simplifying assumptions are useful.…”

Section: Directions For Further Researchmentioning

confidence: 99%

Effects of riparian buffers on nitrate concentrations in watershed discharges: new models and management implications

Weller

Baker

Jordan

2011

Ecological Applications

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Abstract. Watershed analyses of nutrient removal in riparian buffers have been limited by the geographic methods used to map buffers and by the statistical models used to test and quantify buffer effects on stream nutrient levels. We combined geographic methods that account for buffer prevalence along flow paths connecting croplands to streams with improved statistical models to test for buffer effects on stream nitrate concentrations from 321 tributary watersheds to the Chesapeake Bay, USA. We developed statistical models that predict stream nitrate concentration from watershed land cover and physiographic province. We used information theoretic methods (AIC c ) to compare models with and without buffer terms, and we demonstrate that models accounting for riparian buffers better explain stream nitrate concentrations than models using only land cover proportions. We analyzed the buffer model parameters to quantify differences within and among physiographic provinces in the potentials for nitrate loss from croplands and nitrate removal in buffers. On average, buffers in Coastal Plain study watersheds had a higher relative nitrate removal potential (95% of the inputs from cropland) than Piedmont buffers (35% of inputs). Buffers in Appalachian Mountain study watersheds were intermediate (retaining 39% of cropland inputs), but that percentage was uncertain. The absolute potential to reduce nitrate concentration was highest in the Piedmont study watersheds because of higher nitrate inputs from cropland. Model predictions for the study watersheds provided estimates of nitrate removals achieved with the existing cropland and buffer distributions. Compared to expected nitrate concentrations if buffers were removed, current buffers reduced average nitrate concentrations by 0.73 mg N/L (50% of their inputs from cropland) in the Coastal Plain study watersheds, 0.40 mg N/L (11%) in the Piedmont, and 0.08 mg N/L (5%) in the Appalachian Mountains. Restoration to close all buffer gaps downhill from croplands would further reduce nitrate concentrations by 0.66 mg N/L, 0.83 mg N/L, and 0.51 mg N/L, respectively, in the Coastal Plain, Piedmont, and Appalachian Mountain study watersheds. Aggregate nitrate removal by riparian buffers was less than suggested by many studies of field-to-stream transects, but buffer nitrate removal is significant, and restoration could achieve substantial additional removal.

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Section: Directions For Further Researchmentioning

confidence: 99%

Effects of riparian buffers on nitrate concentrations in watershed discharges: new models and management implications

Weller

Baker

Jordan

2011

Ecological Applications

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“…In Michigan, surface topography is the most important factor driving patterns of regional groundwater flow (Hoaglund and others 2002). Elsewhere, research suggests that surface topography can be an important predictor of groundwater flux (Gerhart 1984, Hinton and others 1993, Dawes and Short 1994, Gerla 1999). Thus, this assumption is not at all uncommon in conceptualizations of water table dynamics, although it is clear that it does not hold equally well in all climates or in all stratigraphies (Heath 1987, Winter and others 1998, Winter 2001.…”

Section: Model Limitationsmentioning

confidence: 99%

A GIS Model of Subsurface Water Potential for Aquatic Resource Inventory, Assessment, and Environmental Management

Baker

Wiley

Seelbach

et al. 2003

Environmental Management

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/ Biological, chemical, and physical attributes of aquatic ecosystems are often strongly influenced by groundwater sources. Nonetheless, widespread access to predictions of subsurface contributions to rivers, lakes, and wetlands at a scale useful to environmental managers is generally lackRiver, lake, and wetland ecosystems are strongly influenced by routing of source waters because relative conmbutions of precipitation, runoff, through-flow, and groundwater shape seasonal hydrography, chemical prop erties, thermal characteristics, and ultimately, the character of aquatic biota (Dunne and Leopold 1978, Wiley and others 1997, Winter 2001. Subsurface water inputs in particular can have strong influences on local biology due to their relatively cold summer temperatures, high dis ing. In this paper, we describe a "neighborhood analysis" approach for estimating topographic constraints on spatial pattems of recharge and discharge and discuss how this index has proven useful in research, management, and conservation contexts. The Michigan Rivers Inventory subsurface flux model (MRI-DARCY) used digital elevation and hydraulic conductivity inferred from mapped surficial geology to estimate spatial patterns of hydraulic potential. Model predictions were calculated in units of specific discharge (meters per 4ay) for a 30-m-cell raster map and interpreted as an index of potential subsurface water flux (shallow groundwater and event through-flow). The model was evaluated by comparison with measurements of groundwater-related attributes at watershed, stream segment, and local spatial scales throughout Lower Michigan (USA). Map-based predictions using MRI-DARCY accounted for 85% of the observed variation in base flow from 128 USGS gauges, 69% of the observed variation in discharge accrual from 48 river segments, and 29% of the residual variation in local groundwater flux from 33 locations as measured by hyporheic temperature profiles after factoring out the effects of climate. ARhough it does not incorporate any information about the actual water table surface, by quantifying spatial variation of key constraints on groundwater-related attributes, the model provides strata for more intensive study, as well as a useful spatial tool for regional and local conservation planning, fisheries management, wetland characterization, and stream assessment.

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“…The Shingobee watershed has been the topic of several prior modeling studies (Karls, 1982;Locke, 1995;Gerla, 1999). For this study, a one-dimensional evapotranspiration/unsaturated flow/heat transfer model for the vadose zone was constructed to calculate temporal variations in recharge to the aquifer.…”

Section: Mathematical Modelmentioning

confidence: 99%

Mid-Holocene Hydrologic Model of the Shingobee Watershed, Minnesota

et al. 2002

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A hydrologic model of the Shingobee Watershed in north-central Minnesota was developed to reconstruct mid-Holocene paleo-lake levels for Williams Lake, a surface-water body located in the southern portion of the watershed. Hydrologic parameters for the model were first estimated in a calibration exercise using a 9-yr historical record (1990)(1991)(1992)(1993)(1994)(1995)(1996)(1997)(1998) of climatic and hydrologic stresses. The model reproduced observed temporal and spatial trends in surface/groundwater levels across the watershed. Mid-Holocene aquifer and lake levels were then reconstructed using two paleoclimatic data sets: CCM1 atmospheric general circulation model output and pollen-transfer functions using sediment core data from Williams Lake.Calculated paleo-lake levels based on pollen-derived paleoclimatic reconstructions indicated a 3.5-m drop in simulated lake levels and were in good agreement with the position of mid-Holocene beach sands observed in a Williams Lake sediment core transect. However, calculated paleolake levels based on CCM1 climate forcing produced only a 0.05-m drop in lake levels. We found that decreases in winter precipitation rather than temperature increases had the largest effect on simulated mid-Holocene lake levels. The study illustrates how watershed models can be used to critically evaluate paleoclimatic reconstructions by integrating geologic, climatic, limnologic, and hydrogeologic data sets. RightsWorks produced by employees of the U.S. Government as part of their official duties are not copyrighted within the U.S. The content of this document is not copyrighted. A hydrologic model of the Shingobee Watershed in north-central Minnesota was developed to reconstruct mid-Holocene paleo-lake levels for Williams Lake, a surface-water body located in the southern portion of the watershed. Hydrologic parameters for the model were first estimated in a calibration exercise using a 9-yr historical record (1990-1998) of climatic and hydrologic stresses. The model reproduced observed temporal and spatial trends in surface/ groundwater levels across the watershed. Mid-Holocene aquifer and lake levels were then reconstructed using two paleoclimatic data sets: CCM1 atmospheric general circulation model output and pollen-transfer functions using sediment core data from Williams Lake.Calculated paleo-lake levels based on pollen-derived paleoclimatic reconstructions indicated a 3.5-m drop in simulated lake levels and were in good agreement with the position of mid-Holocene beach sands observed in a Williams Lake sediment core transect. However, calculated paleolake levels based on CCM1 climate 1 Present Affiliation: Barr Engineering Company, Minneapolis, Minnesota 55435.2 To whom correspondence should be addressed. E-mail: maperson@indiana. edu.forcing produced only a 0.05-m drop in lake levels. We found that decreases in winter precipitation rather than temperature increases had the largest effect on simulated mid-Holocene lake levels. The study illustrates how watershed models can ...

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Estimating the ground-water contribution in wetlands using modeling and digital terrain analysis

Cited by 16 publications

References 18 publications

Effects of riparian buffers on nitrate concentrations in watershed discharges: new models and management implications

Effects of riparian buffers on nitrate concentrations in watershed discharges: new models and management implications

A GIS Model of Subsurface Water Potential for Aquatic Resource Inventory, Assessment, and Environmental Management

Mid-Holocene Hydrologic Model of the Shingobee Watershed, Minnesota

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