A spatial optimization approach to watershed water quality management: A case of the Opequon Watershed.

摘要

The Opequon Creek watershed is located in northern VA and the eastern panhandle of WV. Currently, the main creeks in the watershed do not meet VA or WV state water quality standards for recreational uses and aquatic life. In both states, the creeks are listed as impaired due to high levels of nutrients, bacteria, benthic and biologic impairment. The Opequon Creek is part of the upper Potomac River watershed, and ultimately impacts water quality in the Chesapeake Bay watershed. The main aim of this study was to develop a methodology that can be used to reduce nutrient loadings entering the bay area and improve water quality in Opequon watershed by implementing four innovative agricultural BMPs. The study develops an integrated approach to nutrient reduction incorporating three models involving water quality modeling, nutrient fate and transportation and an optimization model to recommend a least cost strategy for nutrient reduction.Four optimization scenarios were evaluated, involving a uniform, holistic, prioritization, and targeted reduction approaches. A uniform reduction approach evaluated each subwatershed to meet a reduction goal. Using specific land use contributions, an annual cost of From a perspective of water resource policy, this study showed that: (1) P goals are more attainable at reasonable cost than N goals so that trading on the Opequon watershed is more likely to be feasible for P than N (2) compliance with WV and VA reduction goals across all subwatersheds is more achievable than meeting a holistic reduction goal for the entire watershed and (3) local knowledge gives comparable information on priority subwatersheds as does watershed modeling.