In 2017, RES partnered with Anne Arundel County to deliver measurable water quality improvements and cost-effective compliance with MS4 permit requirements. By treating stormwater runoff at its source, the program reduced nitrogen, phosphorus, and sediment loads, while generating 133.9 Impervious Acre Credits (IACs) for the County.

The project combined outfall stabilization, wet and dry pond retrofits, and continuous monitoring across three key commercial sites. We partnered with an engineering partner on the retrofit design and MS4 support, while another firm introduced its Continuous Monitoring and Adaptive Control (CMAC) platform, a first for Anne Arundel County. CMAC integrates on-site sensors, weather forecasts, and site-specific data to intelligently manage pond discharges in real time.

Key Sites and Results
Walmart, Arundel Mills Pond: Retrofit increased water quality volume from 0.5-inch to 2.6-inch per impervious acre by adaptively managing 6-vertical feet of storage. Generated 24 IACs.

Arundel Mills Limited Partnership Pond: Adaptive control of 4.7 feet of vertical storage. Raised water quality volume from 1-inch to 2.6-inches per impervious acre. Generated 61.5 IACs.

AJ&C Garfunkel Pond: Converted a dry pond to a stormwater facility, boosting water quality treatment from 0-inches to 2.6-inches per impervious acre by controlling 6.1 feet of vertical storage. Generated 48.4 IACs.

Client Benefits
• Created measurable reductions in nitrogen, phosphorus, and sediment loads
• Generated 133.9 IACs toward MS4 compliance
• Delivered cost-effective retrofits without major land disturbance
• Modernized stormwater ponds into high-performing water quality assets