Enter global climate change – dry, drier and driest. New Priority: The need to retain and store water on a massive scale, to curtail runoff and conserve what has become our most precious nature resource, our dwindling water supply, particularly in the West and the Southwest. “Beaver dams, it turns out, have beneficial effects that can’t easily be replicated in other ways. They raise the water table alongside a stream, aiding the growth of trees and plants that stabilize the banks and prevent erosion. They improve fish and wildlife habitat and promote new, rich soil.
“‘We can spend a lot of money doing this work, or we can use beavers for almost nothing,’ Mr. Burrell said…Beavers are ecosystem engineers. As a family moves into new territory, the rodents drop a large tree across a stream to begin a new dam, which also serves as their lodge. They cover it with sticks, mud and stones, usually working at night. As the water level rises behind the dam, it submerges the entrance and protects the beavers from predators.
“This pooling of water leads to a cascade of ecological changes. The pond nourishes young willows, aspens and other trees — prime beaver food — and provides a haven for fish that like slow-flowing water. The growth of grass and shrubs alongside the pond improves habitat for songbirds, deer and elk… Moreover, because dams raise underground water levels, they increase water supplies and substantially lower the cost of pumping groundwater for farming.
“And they help protect fish imperiled by rising water temperatures in rivers. The deep pools formed by beaver dams, with cooler water at the bottom, are ‘outstanding rearing habitat for juvenile coho salmon,’ said Michael M. Pollock, a fish biologist with the National Oceanic and Atmospheric Administration in Seattle, who has studied the ecological effects of beaver dams for 20 years.” NY Times.