22. Tucson, AZ

This burgeoning city in the Sonoran Desert, close to rugged outdoor recreation and blessed with warm weather, continues to draw new residents. But Tucson faces major challenges when it comes to sustainability, the most acute of which is water. Decades of groundwater mining has transformed the Santa Cruz River, which cuts through the city, into a mostly-dry riverbed, except when it rains. But Tucson officials are making progress on the water front: they already require rainwater harvesting on commercial sites and common areas of sub-divisions, and they’re drafting a residential rain water harvesting ordinance. Suburban sprawl is another issue for Tucson. Environment officials here are strategizing ways to rein in the city’s footprint -- like mandating sustainable, green development in the face of a powerful homebuilding lobby and old-timers’ keep-it-like-it-is attitude. Tucson’s chief sustainability officer says the city is doing a lot to harness solar energy as well, and that the region has the potential to become America ’s Solar Saudi Arabia.

Tucson is part of the national "Solar America City" program. (Photo by Zereshk)

Resources:

• Tucson Office of Conservation and Sustainable Development
• Tucson Environmental Services Division