Field Testing of Ultra-Urban BMPs

Abstract

The paper summarized recent results of field testing of "ultra-urban", or "space-limited", best management practices (BMP's). Beginning in July 1997, the University of Virginia has been testing a vault/reservoir structure installed at a bus maintenance facility in Charlottesville, Virginia. Two larger such structures were later installed in Warrenton, Virginia and were monitored between October 1997 and September 1998. Another ultra-urban BMP, a bioretention area, was installed at a high school site in 1998 and has been monitored since November 1998. A total of 22 storm events were sampled at the vault/reservoir structure sites, and 4 storms have been sampled at the bioretention site. Water quality parameters examined included total suspended solids (TSS); total phosphorus (TP); chemical oxygen demand (COD), and oil and grease (OG). Results for the vault structure show that the smaller structure at the Charlottesville site removed on the average 68% of TSS; 53% of COD; 51% for OG, but only 7% for TP. The larger units in Warrenton removed 75% of TSS; 66% of COD; 79% of OG, and 44% of TP. Maintenance needs, however, is a major concern for such structures. Preliminary results collected at the bioretention site show 86% removal for TSS; 97% for COD; 67% for OG, and 90% for TP. More data are needed for the bioretention area assessment.