Virginia Stream Condition Index for Non-Coastal Streams (VSCI)
In an effort to assist DEQ in updating the biological monitoring program in Virginia to reflect recent advances in bioassessment methods, Rapid Bioassessment Protocols at http://www.epa.gov/owow/monitoring/rbp, the U.S. Environmental Protection Agency funded their contractor Tetra Tech Inc. to prepare a report recommending a method for evaluating the ecological health of freshwater non-coastal streams in Virginia. Tetra Tech has produced a final report titled A Stream Condition Index for Virginia Non-Coastal Streams that under went an evaluation and testing by DEQ. This index contains eight core metrics that when calculated into one number is known as the Virginia Stream Condition Index (VSCI) (Tetra Tech, 2003).
Using Probabilistic Monitoring Data to Validate the Non-Coastal Virginia Stream Condition Index (VSCI)
Using a new, independent probabilistic monitoring program (ProbMon) database (number of stations = 350, 2001-2004), VDEQ has validated the VSCI using a spatially diverse (ecoregionally and stream size) data set free of psuedoreplication. These probabilistic data sets have allowed VDEQ to narrow data gaps and test the proposed VSCI against many classification variables, which include season, stream size, ecoregion, bioregion, river basin, regional office, and sampling technique. Reviewing the probabilistic biological data has confirmed that the VSCI works well to discriminate between sites with acceptable water quality and habitat versus sites with degraded water quality and habitat.