Woolpert was retained to assist the Gwinnett County Department of Water Resources to establish a baseline of stormwater quality at the One Justice Square (OJS) administration building. The baseline data is needed as the county plans to retrofit the existing storm sewer system and parking lot to incorporate various low impact development (LID) best management practices (BMP).

Woolpert’s team developed a strategic monitoring plan to identify in detail the project’s goals and objectives. The subsequent comprehensive monitoring plan included field inspection for appropriate sampling/monitoring locations; identification of appropriate collection methods/materials; analytical testing procedures and procurement of a laboratory; and providing data storage/quality control procedures.

Woolpert installed Isco automatic samplers for collections and area-velocity sensors to measure discharge at the inlet/outlet of the existing dry detention pond. To gauge rainfall, a tipping bucket was installed on the rooftop of the OJS building and autoclaved buckets were deployed before each rain event to evaluate water quality. The team deployed remote telemetry at each station to trasmit data to a dedicated website for use by staff from Woolpert and the county. To improve event capture for each measured storm event, Woolpert watches weather forecasts and radar and conducts flow compositing after each storm.

Woolpert has successfully collected over 15 events and continues to collect data to establish baseline conditions. The work is providing the information needed for the county’s water resources department to evaluate the effectiveness and efficiency of future retrofits to the OJS building as a BMP system.

Client
Gwinnett County, Georgia

Location
Gwinnett County, GA