This flyer documents high-level results of one technical recommendation of the Potomac Basin Comprehensive Water Resources Plan’s water use and supplies challenge area: specifically, to “conduct additional studies on water uses that fall below state water reporting thresholds.”
Potomac Basin Unreported Water Use Archives
In accordance with one of the technical recommendations of the Potomac Basin Comprehensive Water Resources Plan’s water use and supplies challenge area, this pamphlet has been produced to document and share high-level results. This pamphlet provides a “report on basin-wise water uses,” and ultimately acts as a first step toward estimating, “projected demands and consumptive demands.”
The project examined whether stormwater management practices implemented under MS4 permits can lead to measurable differences in stream conditions compared to similar watersheds with few or no stormwater practices and to highly forested reference watersheds.
This report describes how monitoring and model data were analyzed and combined to generate a preliminary estimate of acceptable stream health in the Chesapeake Bay basin for the 2006 – 2011 baseline period. Streams in about 73% of the basin’s 64,020 sq. miles of drainage area were evaluated with monitoring results, and output from a predictive model was used to estimate stream health in the remaining 27%. Stream health was measured with the bioregion, family-level version of the “Chessie BIBI,” a multi-metric index for stream macroinvertebrate communities. Index scores are normally expressed as one of five index ratings: Excellent or Good (well-functioning), Fair (considered satisfactory), and Poor or Very Poor (stressed or poorly-functioning). Four versions of the predictive model were developed and tested, and the selected version outputs results as three-ratings: Excellent/Good, Fair, and Poor/Very Poor. The five ratings in the monitoring data were re-grouped to match the three ratings of the selected predictive model. The monitoring- and model-based ratings were then area-weighted to reduce bias caused by uneven sample densities and aggregated to the Chesapeake basin scale, with monitoring results given preference. The combined results suggest approximately 60% of the basin’s area had acceptable stream ratings (Excellent, Good, or Fair) during 2006 – 2011. This estimate is a preliminary baseline for the Chesapeake Bay Program’s stream health goal. A final baseline estimate will be produced after a higher resolution stream layer becomes available and acceptable stream health can be estimated as a percent of the basin’s stream miles.
The report has been published in Freshwater Science 37, no. 4 (December 2018)
This project evaluated the relationship between forest cover and source water quality in the form of nutrients, sediments, and total organic carbon (TOC). More information can be found on ICPRB’s page, Forests and Water Treatment Costs.
Prepared by ICPRB for Virginia Department of Environmental Quality (DEQ). This is the Technical Report for the Upper Goose Creek, Cromwells Run, and Little River TMDL Implementation Plan.