Kansas is demanding that Nebraska pay $72 million for using too much Republican River water.

The demand was outlined in a letter from Chief Engineer David Barfield of Kansas' Division of Water Resources. He sent it Tuesday to Brian Dunnigan, the acting director of Nebraska's Department of Natural Resources.

Kansas contends that Nebraska took 27 billion gallons of water more than it was entitled to from the Republican River in 2005 and 2006. Nebraska contends it has been taking significant steps to cut its water use.

Kansas already has proposed that Nebraska shut down wells within 2 1/2 miles of the river and its tributaries where irrigation started after 2000.