A recent report by the Intergovernmental Panel on Climate Change (IPCC) highlights the fact that the effects of climate change are already transpiring, and that cities will need to adapt to these changes. As a city with large amounts of land residing in a low-elevation coastal zone, the most pressing challenge for Washington, D.C. will be the potential for flooding in relation to sea-level rise and an increase in the frequency and intensity of storms. Preparing for this possibility is essential in a city already facing a plethora of water management issues – issues which will only be exacerbated by climate change.

Green Infrastructure in Yards Park, SE Washington, DC

One of the primary methods the District is pursuing to help manage these issues is the proliferation of green infrastructure throughout the city. The District Department of the Environment, for instance, offers a Green Roof Rebate to provide financial incentives for property owners to help with the burden of water management, while providing benefits to the tenants of their buildings. The program is already starting to see success, with the District now housing more than two million square feet of green roofs.

D.C. Water and the District Department of Transportation (DDOT) are also involved in their own green infrastructure initiatives. D.C. Water’s latest plan would instill massive amounts of green infrastructure throughout some of the District’s most vulnerable watersheds. Apart from reducing the risk of flooding, it would also help to filter stormwater to reduce water pollution problems. Meanwhile, DDOT has published its own green infrastructure guidelines in accordance with the Sustainable D.C. Plan.

However, the boldest action the District government has taken is the creation of a Stormwater Retention Credit Trading Program. This is akin to a carbon cap-and-trade program, but instead creates a market for trading stormwater runoff. A baseline requirement is in place for a 0.8 inch retention of stormwater for substantial improvements, and 1.2 inches for major land disturbing developments. As developers retain more stormwater, they receive credits that can then be traded to developers unable to meet their requirements.

Roadside bioswale in NW Washington, DC

While all of these green infrastructure initiatives are encouraging, climate science tells us that the amount of precipitation will likely increase in the Mid-Atlantic. With this knowledge the question is begged whether the green infrastructure the District is implementing today will be adequate for the future?

How much should urban planners invest in crafting adaptive strategies that can take into account future impacts, especially when the effects are so uncertain?

Credits: Images by Chase Keenan. Data linked to sources.