What are the environmental impacts of our water use?

In addition to economic prosperity, water diversions have brought environmental consequences. 

Mono Lake, millions of years old, dropped 25 feet, nearly destroying its scenic ecosystem, when Los Angeles diverted the Eastern Sierra’s water. The San Joaquin River nearly dried up. Yosemite’s Hetch Hetchy disappeared under reservoirs. And the Colorado River, in most years, is empty before it reaches its estuary at the Sea of Cortez.

Dams blocked migration routes of salmon and steelhead, and then diversions, levee construction and development created poor conditions for the surviving fish. Coho salmon, steelhead and green sturgeon are listed under the Endangered Species Act, and many salmon runs are expected to vanish this century. In addition, the tiny Delta smelt is almost extinct. The totuava, an ocean fish that can reach 300 pounds, once spawned in great numbers in the Colorado River Delta but is now scarce.

Much of the conflict over California’s water focuses on the Endangered Species Act. To protect species, pumping from the Delta is reduced. This creates strife between environmentalists and growers. Some biologists say more water needs to be left for river fish as well as San Francisco Bay creatures such as crab, herring and halibut.

Source: National Marine Fisheries Service