SEATTLE, Wash., Feb 1 Reuters The Colorado River, which provides drinking water to 40 million people in seven U.S. states, is drying up, straining a water distribution pact amid the worst drought in 12 centuries, exacerbated by climate change.

California split from the six states of Arizona, Colorado, Nevada, New Mexico, Utah and Wyoming on Tuesday in the face of a U.S. government deadline to negotiate their own supply cuts or face possible mandatory cutbacks by the federal government.

What happened today was a step forward, said Kevin Moran, a water policy specialist at the Environmental Defense Fund.

Six of the seven basin states are playing catchup to reduce water use from the Colorado River, which is absolutely critically needed after 20 years of drought and the impacts of climate change, Moran told Reuters.

When the states struck their agreement 100 years ago, it envisaged the river could provide 20 million acrefeet of water a year. An acrefoot 1,233 cubic meters of water is generally considered enough to supply two urban households per year.

But over the last two decades, the actual flow has dwindled to 12.5 million acrefeet on average, leaving state water managers with more rights on paper than existing supply.

California receives the largest allotment, 80 of which is consumed by its 50billion agricultural industry.

Many experts see its decision to sit out the agreement as fuelling the chances that the water fight will end up in the nation39;s highest…