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Distributed Large Basin Runoff Model
About
Agricultural non-point source contamination of water resources by pesticides, fertilizers, animal wastes, and soil erosion is a major problem in much of the Great Lakes Basin. Point source contaminations, such as Combined Sewerage Overflows (CSOs), also add wastes to water flows. Soil erosion and sedimentation reduce soil fertility and agricultural productivity, decrease the service life of reservoirs and lakes, and increase flooding and costs for dredging harbors and treating waste-water. Improper management of fertilizers, pesticides, and animal and human wastes can cause increased levels of nitrogen, phosphorus, and toxic substances in both surface water and groundwater. Sediment, waste, pesticide, and nutrient loadings to surface and subsurface waters can result in oxygen depletion and eutrophication in receiving lakes, as well as secondary impacts such as harmful algal blooms and beach closings due to viral and bacterial and/or toxin delivery to affected sites. The U.S. Environmental Protection Agency (USEPA website) has identified contaminated sediments, urban runoff and storm sewers, and agriculture as the primary sources of pollutants causing impairment of Great Lakes shoreline waters . Prediction of various ecological system variables or consequences (such as beach closings), as well as effective management of pollution at the watershed scale, require estimation of both point and non-point source material transport through a watershed by hydrological processes. However, currently there are no integrated spatially distributed physically based watershed-scale hydrological/water quality models available to evaluate movement of materials (sediments, animal and human wastes, agricultural chemicals, nutrients, etc.) in both surface and subsurface waters in the Great Lakes watersheds.
The Great Lakes Environmental Research Laboratory (GLERL) and Western Michigan University (WMU website) are developing an integrated, spatially distributed, physically-based water quality model to evaluate both agricultural non-point source loading from soil erosion, fertilizers, animal manure, and pesticides, and point source loadings at the watershed level. GLERL is augmenting an existing physically based surface/subsurface hydrology model, their Large Basin Runoff Model, by adding material transport capabilities to it to create a Distributed Watershed Model. This will facilitate effective Great Lakes watershed management decision-making, by allowing identification of critical risk areas and tracking different sources of pollutants for implementation of water quality programs, and will augment ecological prediction efforts.
Last updated: 2006-09-08 ks