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:

Rain gardens
Landscape depressions are lined with
crushed stone and filled with soil that has been
engineered to drain well.

Bioswale
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.

Porous pavement
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.

Plantings
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.