Every time it rains hard in Washington, DC, some neighborhoods face a choice nobody should have to make: sewage in their basements or flooded streets. This isn't a new problem, and it's not one that money alone can solve.
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Every time it rains hard in Washington, DC, some neighborhoods face a choice nobody should have to make: sewage in their basements or flooded streets. This isn't a new problem, and it's not one that money alone can solve. What's happening here is a decades-old infrastructure design finally colliding with modern rainfall patterns and environmental law. Approximately one-third of Washington DC is served by an aging combined sewer system that collects both stormwater and sewage in the same pipes. [1] When a storm hits, those pipes overflow directly into the Potomac and Anacostia Rivers. The city is now in the middle of one of the most ambitious urban water infrastructure transformations in the country.
But to understand why, you need to understand what forced DC's hand. In 2005, DC Water entered into a consent decree with the US Environmental Protection Agency to address combined sewer overflows, or CSOs. [2] That was the moment when federal environmental law said: this stops.
The original plan was straightforward—if inelegant. Build massive underground storage tunnels beneath the rivers. Store the sewage and stormwater during storms, then release it later. This is gray infrastructure: concrete, engineering, scale. [2] The original CSO control plan primarily involved building large underground storage tunnels, with some green infrastructure as a secondary component. [2] But something shifted. An amendment to the 2005 consent decree was entered on January 14, 2016, modifying the plan to include a larger portion of green infrastructure. [2] That amendment changed everything. The strategy moved away from "bigger tunnels" toward a hybrid approach: massive storage capacity paired with smaller, distributed solutions scattered across the city.
The gray infrastructure backbone is massive. [2] Major gray infrastructure projects include the Anacostia River Tunnel with 157 million gallons storage capacity, Potomac River Tunnel with 58 million gallons storage capacity, and Rock Creek Tunnel with 9. 5 million gallons storage capacity. Combined, these three tunnels represent billions in investment. When projections were made in 2013, the District's retrofitting of its combined sewer system carried an estimated cost of 2. 6 billion dollars. [1] But here's where the story becomes more interesting. That 2. 6 billion figure was developed around tunnels. Then came the green infrastructure revolution. DC Water adapted the Clean Rivers Project to incorporate 100 million dollars of green infrastructure.
As of 2020, DC Water had spent more than 80 million dollars on green infrastructure as part of its efforts to meet consent decree requirements. [3]
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