Performance of Low Impact Development Compost BMPs On Storm Water Quality.

Low Impact Development (LID) strategies use natural design principles to decentralize storm water management and restore natural site hydrology, while compost best management practices (BMPs) utilized in LID maximize the services of nature to reduce runoff, filter pollutants, impliment bio-based materials, reduce carbon emissions, and accrue LEED green building credits. This presentation will focus on the latest research from universities and federal agencies evaluating these BMPs, and how this information is being used to meet LID and LEED objectives and reduce carbon emissions affecting climate change at the same time. Recent research conducted at the University of Georgia, Auburn University, and San Diego State University evaluated compost blankets relative to other BMPs and found compost blankets can reduce storm water sediment loads by 90%, total suspended solids by 90%, total nitrogen by 92%, and total phosphorus by 97%. Under 50 and 100 yr design storms, compost blankets have been shown to absorb 80% of total rainfall, reduce runoff volume by 60% and reduce peak runoff rate by 40%. From these studies runoff curve numbers and coefficients have been developed and utilized to reduce the size of storm water ponds and conveyance systems by restoring the natural site hydrology. Recent experiments conducted at the US Department of Agriculture-Agricultural Research Service (USDA-ARS) evaluated the performance of compost socks in reducing storm water runoff flow transport of sediment and soluble pollutants. These experiments focused on evaluating the performance of compost socks on bare soil and paved surfaces. Results showed compost sock removal efficiencies for TSS concentration and load, turbidity, and total and soluble P were between 62 and 97%, 53 and 98%, and 57 and 99%, respectively. Follow up studies have been conducted at the USDA-ARS to evaluate the performance of compost filter socks on reducing: i) runoff nitrogen (N) (ammonia-N and nitrite-nitrate-N) loads, ii) runoff bacterial pathogens (fecal coliform and E. coli) loads; iii) runoff heavy metals (nickel, cadmium, chromium, copper, lead, zinc, and iron); and iv) runoff petroleum hydrocarbon loads. Results from these studies will be presented.