“The idea is to integrate the harvested water with cultivating desert-adapted plants. In 2013, the city [Tucson] implemented a Green Streets policy, requiring that new and reconstructed roadways be designed to harvest the 10.6 inches (270 millimeters) of rainfall the city gets per year to sustain such plants near the road. “That meant that the city itself was practicing what it was advocating for other people,” Eden said.”
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Urban Water Conservation Success in the Colorado River Basin – Eos