Reduced runoff from DC buildings? New EPA rules

One way that urban areas affect the environment is by having lots of "impervious areas" which send storm water rushing into drains and out into bodies of water carrying whatever chemicals or trash are in their path. This is one reason the harbor area in Baltimore is so dirty, and high speed flows hitting tributaries of the Chesapeake disrupt local ecosystems. The EPA is proposing to require green roofs in the District, which will slow the water and see much of it captured in barrels for use watering plants later. This could be pretty expensive, but it will definitely leave us with cleaner rivers and hopefully a cleaner Bay. Hopefully it's worth it!