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The Potential Importance of Conservation, Restoration, and Altered Management Practices for Water Quality in the Wabash River Watershed
Citation:
Yang, G. AND Elly Best. The Potential Importance of Conservation, Restoration, and Altered Management Practices for Water Quality in the Wabash River Watershed. Presented at 9th National Monitoring Conference-Working Together for Clean Water, Cincinnati, OH, April 28 - May 02, 2014.
Impact/Purpose:
To inform the public
Description:
Non-point source (NPS) pollution is one of the leading causes of water quality impairment within the United States. Conservation, restoration and altered management (CRAM) practices may effectively reduce NPS pollutants discharge into receiving water bodies and enhance local and regional ecosystem services. Barriers for the implementation of CRAM include uncertainties related to the extent to which nutrients are removed at various spatial and temporal scales, longevity, optimal placement within the landscape, and implementation / operation / maintenance costs. We conduct a study to explore extent, geographical distribution, and spatial scale, determining load reduction in a relatively small watershed to a level below which an 'accepted' nutrient standard becomes insignificant relative to the overall nutrient load routed downstream through a far larger watershed. The study results are expected to provide information on local, regional, and national significance of CRAM implementation for water quality standard attainment. For this study, we use a recently developed screening-level modeling approach, WQM-TMDL-N, running in the ArcGIS environment, to estimate annual total nitrogen(TN) loading and average TN concentration; and expanded this with a new option to explore CRAM effects on TN and concentration, and multi-objective algorithm optimizing load and cost. We apply this modeling approach to the Wabash River (WR, HUC 4) watershed, IN, where land use is predominated by agriculture and CRAM implementation is being planned and implemented. CRAM practices explored include buffer strips, nutrient management practices, and wetland restoration. Because the WR accounts for over 40% of the nutrient loads of the Ohio River, which in turn significantly contributes to the anoxic zone in the Gulf of Mexico, reduction in TN loading of the WR is expected to directly benefit downstream ecosystem services. Results of initial model applications indicate that the implementation of buffer strips and nutrient management practices may significantly contribute to local and regional water quality standard attainment, and wetland restoration may even exceed these effects - with the latter offering potential solutions for water quality issues. Decisions on CRAM implementation for water quality improvement take cost into consideration, and, therefore, our pollutant load-cost optimization algorithm is expected to facilitate the decision-making process.
