Nashville, Tennessee, USA

Nashville has pursued green-infrastructure flood mitigation — depaving, tree planting, and rain gardens — as part of its response since the catastrophic 2010 flood. This case study is included specifically for its honest limitation. The executive director of the Cumberland River Compact has been explicit that a depave project cannot absorb all the water in extreme, isolated rainfall events, and that depaving, trees, and rain gardens must be deployed at the top of the watershed — because by the time water reaches the bottom of the catchment there is too much of it to handle. The conclusion drawn locally is that effectiveness depends on many decentralized efforts sinking water into the ground across the watershed, complemented by non-green measures such as property buyout programs and improved public alert systems. Marked partial: green infrastructure measurably helps with frequent flooding but does not by itself solve rare extreme events.