The U.S. Environmental Protection Agency (EPA) has signed an agreement with the District of Columbia to implement major green infrastructure enhancements to protect the Potomac and Anacostia rivers from storm-water runoff.

In modifications to a Clean Water Act permit, the district has agreed to undertake measures to stem storm-water flow and pollution, using natural systems such as trees, green roofs, and vegetated buffers.

Highlights of the new measures include:

• creating a tax-incentive plan for the installation of green roofs
• requiring all new district-owned buildings and, where feasible, all major renovations of district-owned buildings to include green roofs
• planting and maintaining at least 13,500 additional trees
• devising a low-impact development plan that will include converting paved areas, such as median strips and large sidewalks, into green space
• implementing enhanced programs for street sweeping and trash removal
• installing 50 rain gardens and 125 rain barrels.