Assessing Nutrient Credit Trading and Local Water Quality in the Rivanna Watershed

Abstract

Due to the impairments of the Chesapeake Bay, a Total Maximum Daily Load (TMDL) has been applied to reduce nutrient and sediment discharges. The state of Virginia has adopted nutrient trading regulations to meet required pollutant reductions. Although these policies reduce overall pollutant discharges to the Bay, this benefit is not fully realized at the local watershed level. This report evaluates nutrient credit trading and potential impacts on local water quality in the Rivanna watershed. The results show that nutrient trading has been increasing, and that the majority of credits are generated outside of the watershed, providing environmental benefits to adjacent watersheds. Nutrient trading also provides a cost-effective option to implementing onsite post-construction best management practices (BMPs), which creates the opportunity for missed benefits to local water quality and ecosystem services during redevelopment.