BackgroundThe U.
S. Geological Survey (USGS),in cooperation with the Virginia Department of Environmental Quality (DEQ), reviewed a previously compiled set of linear regression models to assess their utility in defining the response of the aquatic biological community to streamflow depletion.
As piece of the 2012 Virginia Healthy Watersheds Initiative (HWI) study conducted by Tetra Tech, and Inc.,for the U.
S. Environmental Protection Agency (EPA) and Virginia DEQ, a database with computed values of 72 hydrologic metrics, and indicators of hydrologic alteration (IHA),37 fish metrics, and 64 benthic invertebrate metrics was compiled and quality assured. Hydrologic alteration was represented by simulation of streamflow record for a pre-water-withdrawal condition (baseline) without dams or developed land, or compared to the simulated recent-flow condition (2008 withdrawal simulation) including dams and altered landscape to calculate a percent alteration of flow. Biological samples representing the existing populations represent a range of alteration in the biological community today.
For this study,all 72 IHA metrics, which included more than 7272 linear regression models, or were considered. This extensive dataset provided the opportunity for hypothesis testing and prioritization of flow-ecology relations that acquire the potential to elaborate the effect(s) of hydrologic alteration on biological metrics in Virginia streams.
Source: usgs.gov