Low Impact Development Retrofit at DC Water Facilities
Greeley and Hansen, A TYLin Company, designed Low Impact Development Retrofit techniques for demonstration purposes to address Consent Decree requirements.
Application of the LIDR techniques at existing DC Water properties minimized the need for coordination with other public entities which enabled quick implementation of the project to meet schedule milestones. The major LIDR components designed as part of the project included: a 45,000 square foot (sf) green roof on top of a covered drinking water reservoir, a 6,500 sf green roof over a 45 MGD wastewater pumping station and bioretention areas totaling 3,250 sf that accept and treat runoff from a water pumping station site located in a dense urban setting. Biosolids produced at the DC Water Blue Plains Advanced Wastewater Treatment Plant (AWWTP) were applied to the LIDR areas resulting in a sustainable and beneficial reuse of a byproduct produced at the AWWTP.
The project also incorporated permeable pavers into parking spaces to encourage infiltration and reduce peak runoff volume at two of the DC Water facilities. The Project’s benefits will be measured via a monitoring program to obtain data regarding the effectiveness of LIDR in the reduction of stormwater runoff volume and pollutant removal rates. For each project site, the stormwater runoff quantity will be determined from a recorded flow measurement prior to the incorporation of the LIDR components. After LID improvements have been completed, flow measurements will be recorded for a minimum of one year.
Project Highlights:
- Green infrastructure planning and design
- Hydraulic modeling for combined sewer system
- Monitoring program to determine effectiveness of green infrastructure