A Watershed Approach to Water Quality Enhancement: Edwards Branch Water Quality Enhancement Project

As part of Mecklenburg County's Surface Water Improvement and Management (SWIM) Program, Mecklenburg County Department of Environmental Protection (MCDEP), is undertaking comprehensive restoration in the Edwards Branch watershed. The goal is to restore waters in Edwards Branch, and ultimately the entire County, to “swimmable and fishable” condition. The water quality project is coordinated closely with an ongoing City of Charlotte Storm Water Services (CSWS) flood control project, demonstrating that flood control and water quality improvement can both be achieved.Edwards Branch watershed is a highly urbanized watershed including single and multi-family residential, commercial, and industrial land uses along with public parks, a cemetery, public and private schools, and churches. There are two ponds and one major waterway--Edwards Branch--with three tributaries. CH2M HILL uses land use, soils, and hydrologic boundary GIS coverages to calculate pollutant loadings in the watershed with CH2M HILL's ArcView application PLOAD. Specific water quality problems are being assessed based on ambient monitoring to supplement the pollutants predicted by PLOAD—typically sediment, nutrients, metals, and fecal coliform. Habitat assessment and biological monitoring are also being conducted. BMPs effective at treating the pollutants found to be problematic in the basin have been designed and will be constructed.CH2M HILL also evaluated the physical condition and potential of the watershed's streams using fluvial geomorphologic principles and Rosgen's stream classification system. Natural channel design techniques will be used to restore and stabilize almost 3,000 linear feet of intermittent and perennial streams.The basin-wide BMP plan includes design and construction/implementation of wet ponds, multiple pond/marsh systems, sand filters, bioretention areas, riparian forest buffers, level spreaders, filter strips, stream bank stabilization, stream channel restoration, constructed wetlands, and targeted public education programs. All structural BMP are designed as retrofits of existing facilities in the developed watershed or integrated into the existing land uses. Baseline, construction, and post construction monitoring, using EPA stream habitat assessment protocols, ambient water quality monitoring, fish and benthic macroinvertebrate surveys, and channel cross section monitoring, have been and will continue to be used to collect data to justify implementation of successful practices County-wide.