Beaver were once abundant throughout North America but they were trapped nearly to extinction by the end of the 19th century. A keystone species, the loss of beaver to our watersheds has been incalculable . . . streams that once had water in them all year round now run dry. Waters that once meandered slowly across the landscape began to cut down into stream banks once held together by riparian vegetation like willows, cottonwoods, and aspens. In the 1950s, the Army Corps of Engineers set out to remove what beaver remained and straighten stream channels to bring water down to multi-million dollar reservoirs more quickly. Now those reservoirs are filling with silt, and increasingly there is not even enough water to fill them, leaving farms and cities to fight over dwindling water supplies. Climate change promises to make these problems even worse. Higher temperatures…