In a rugged, sparsely populated patch of Arizona, there’s a fragile system of rivers and creeks that cuts through the desert. The San Pedro River and its tributaries, locals and environmentalists say, are a unique gem. Now, they’re sounding the alarm about a number of potential threats to its water and surrounding ecosystems. Residents are pushing back on a number of proposed developments, including two mining projects, a natural gas pipeline and a petroleum pipeline. Organizers say they could harm the San Pedro, one of the last undammed, free-flowing rivers in the Southwest, and the Aravaipa Canyon area, a striking section of wilderness that attracts tourists from around the state. Melissa Crytzer Fry, chair of the board of directors for the Lower San Pedro Watershed Alliance, said new mining activity could pose a “grave danger” by leading to over-pumping of groundwater.

Other water and mining news:

• Public News Service: Indigenous water supplies threatened by abandoned mines
• International Atomic Energy Agency: Blog: How isotopes protect mining water resources