Maps reveal that the Bureau of Reclamation and Fish and Wildlife Service have very different views on water use that have long made it difficult for the agencies to work together.
Many Klamath Basin farmers are drilling wells to supplement their water supply, but more wells may only exacerbate the water shortage by depleting the aquifer.
In the Klamath River Basin on the Oregon-California border, farmers, Indians, wildlife refuges and now three endangered fish are fighting over scant water in a dry year, and some say the Endangered Species Act only makes the situation worse.
The EPA has taken Idaho rancher John Simpson to court for clearing debris and beaver dams out of a channel of the Salmon River, although endangered salmon have since spawned in the channel, complicating the issue.
More than 7,000 gallons of diesel fuel accidentally dumped in a water-quality monitoring well at Copper Mountain ski resort, Colo., have yet to be found.
The Coeur d'Alene Tribe and the State of Idaho are fighting in the Supreme Court over Lake Coeur d'Alene, with the tribe claiming partial ownership of the lake under a 19th century treaty.
The Metropolitan Water District's plan to tap aquifers at Cadiz, Calif., for Los Angeles could harm the fragile groundwater system that sustains the desert, including the Mojave National Preserve.
Under the Clean Water Act, aquatic pesticides can no longer be used in public waterways without a federal permit.
Under the "4.4 Plan," California will begin a water diet, designed to reduce the state's use of Colorado River water over the next 15 years to the 4.4 million acre-feet it has long been allocated, but always exceeded.