TMDL Implementation Plan Development for a Rapidly Urbanizing Watershed in Northern Virginia

Abstract

The Center for TMDL and Watershed Studies at Virginia Tech led development of a TMDL Implementation Plan (IP) for the Opequon Creek watershed, which includes portions of Virginia's Clarke and Frederick counties and encompasses the City of Winchester. The IP addresses impairments on five stream segments in the watershed. Two segments have bacteria impairments, while three segments have both benthic and bacteria impairments. Urban and agricultural nonpoint sources are cited as causes of the impairments, with urban being the primary cause in a large portion of the watershed. The IP development process included an intensive public participation process involving a Resource Team (comprised of personnel from three universities, two state agencies, and a local watershed group), a Steering Committee (representatives from local government, watershed groups, and watershed residents); and two Working Groups (urban and rural). Through facilitated sessions, the working groups identified potential corrective actions and the Steering Committee prioritized the actions with respect to likelihood of adoption and other characteristics. These actions were then quantified using spatial data analysis and watershed modeling. The IP includes the types and quantities of necessary corrective measures; measurable goals; and the associated costs and benefits of addressing the impairments. While many of the potential benefits resulting from improved water quality within the watershed are difficult to quantify, the value of two specific benefits - improved aquatic life (game fish population) and the safety of swimming and wading - was estimated to range from $2.0 to $2.75 million, based on responses to a survey mailed to watershed residents.