Much like other industrial cities, Washington, D.C.'s rivers—the Anacostia and Potomac—suffered from centuries of pollution. Increasing rain events have led to the more and more combined sewer overflow events, dumping untreated sewage into the rivers and rendering them toxic.
In the past 15 years, D.C. has undertaken one of the most ambitious urban clean water efforts in the country, investing in a two-pronged approach:
🚇 The Clean Rivers Project
🌿 The Stormwater Retention Credit (SRC) Trading Program
With over $2.7 billion in investment—including a landmark $350M, 100-year green bond—this project includes a combination of grey and green infrastructure to divert combined sewer flows to the Anacostia River, Potomac River, and Rock Creek. The most significant grey infrastructure investment of the Clean Rivers Project are three large tunnels, some are over 100 feet underground and 23 feet wide, channeling stormwater to the Blue Plains treatment facility instead of polluting the rivers. This tunnel system of nearly 18 miles will lead to 96% system-wide reductions.
To complement the Clean Rivers’ grey infrastructure approach, D.C. created the first-ever stormwater credit trading market. Developers required to manage runoff can either build green infrastructure—like rain gardens, green roofs, and permeable pavement—or buy credits from others who’ve built surplus GSI elsewhere in the city.
In just 10 years, this market has helped:
✔️ Generate millions of square feet of green infrastructure
✔️ Capture and clean over 40 million gallons of stormwater annually
✔️ Redirect private dollars to the areas that need it most
Together, these investments are transforming the city. Recreational access is returning. Wildlife habitats are being restored. And waterfront developments like The Wharf and The Yards are rising along cleaner, more vibrant waterfronts.
If you're interested in more detailed information about these projects or DC Water's innovative financing initiatives, feel free to ask!
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