Meeting TMDL Objectives with Continuous Monitoring and Adaptive Control (CMAC) Technology in Lynchburg, VA
Located in the Chesapeake Bay watershed, the City of Lynchburg, VA’s Phase II MS4 permit requirements include the traditional six minimum control measures as well as Chesapeake Bay TMDL Action Plan goals. In 2017 the City chose to retrofit an existing regional dry detention facility with Continuous Monitoring and Adaptive Control (CMAC) technology. Using advanced sensors, automated valves, and an intelligent control platform, this smart technology leverages real-time data and weather forecasts to optimize stormwater management. In summary, CMAC technology mimics the behavior of a wet pond by storing stormwater runoff generated during a storm event, holding it for a defined period of time to facilitate water quality improvement, and releasing it during dry weather, thereby eliminating or greatly reducing wet weather flows. This retrofit helps contribute substantially to the City’s Chesapeake Bay TMDL reduction requirements while boosting the community’s flood resilience. The project’s annual TMDL reduction credit equals 54 pounds of phosphorus, 446 pounds of nitrogen, and nearly 33,000 pounds of sediment. The capital cost of phosphorus reduced was only $1,850/lb making this CMAC retrofit one of the least expensive TMDL reduction project types. Additionally, the project yielded approximately 8 pounds of nitrogen for every pound of phosphorus reduced, which is a better ratio than many other TMDL project types such as stream restoration. From a stormwater quantity standpoint, CMAC controls approximately 157,000 cubic feet of stormwater and routinely reduces peak flows by over 40 percent. In addition to the quality and quantity benefits, CMAC’s realtime data indicated a leak in the embankment before it became a major repair item. Opti is the leading provider of digital adaptive stormwater control solutions, empowering customers and partners to address the impacts of climate change, aging infrastructure, urbanization, and water pollution, enabling them to secure the sustainability of our communities and natural resources. Opti’s cloud-based platform optimizes stormwater asset performance through instant actionable insights to provide economic savings, resilient solutions, and peace of mind. With our commitment to innovation, we are driving a resilient and brighter future for all.
Author Bio
Jason Murnock has been assisting clients with solutions to water quality and stormwater management issues here in the Chesapeake Bay area since 2002. Representing OptiRTC and their CMAC technology has been a great addition to this history, providing an innovative way for communities and owners of stormwater management facilities to see how the facility is functioning in real-time and enabling greater quality and quantity benefits over passive configurations. Ms. Hawkins is the Water Quality Manager with the City of Lynchburg's Department of Water Resources. She is responsible for overseeing the implementation of the City’s MS4 Phase II General Permit, TMDL Action Plans, management of the stormwater utility, and also working with the Combined Sewer Overflow program. Erin serves as the community Floodplain Manager and has had an active role in updating the region's Hazard Mitigation Plan, developing the Flood Resilience Plan, and the Local Emergency Planning Committee.
