D.C. Clean Rivers Project aims for green infrastructure
The decades-long construction program called the Clean Rivers Project aims to greatly reduce sewage overflows in areas that use the same drainage system for sewage and stormwater. A proposal would modify the project by replacing all or part of two planned tunnels with plant-filled drainage areas called “green infrastructure.” Read related article.
Area where runoff and wastewater share the same drainage system
Proposed areas within the same system that would become green infrastructure areas
Tunnel system would hold stormwater and raw sewage that would otherwise be discharged into waterways.
No firm plan exists,
but these components
are likely to be included:
Landscape depressions are lined with
crushed stone and filled with soil that has been
engineered to drain well.
These are basically rain gardens placed on a slope, such as the side of a roadway.
Cisterns and rain barrels
Rain is captured and reused. The barrels are typically connected to a discharge system that allows water to drain slowly.
Specially designed concrete, asphalt and pavers let water infiltrate rather than run off. A crushed-stone layer is usually placed below to hold on to more water.
All new plants would be native species, because they are the most tolerant of the local climate.
SOURCE: Bethany Bezak, green infrastructure planning coordinator at D.C. Water and Sewer Authority; D.C. Clean Rivers Project. GRAPHIC: Bonnie Berkowitz and Laris Karklis - The Washington Post.