Topeka ? Officials from Kansas, Nebraska and Colorado have agreed on a model for regulating use of the Republican River — a plan for making more water available to Kansas farmers and cities in dry years.

The model, announced Tuesday, is a final piece of a settlement to a lawsuit filed by Kansas in 1998 after farmers complained they were not getting their fair share of the water.

Kansas sought to bring Nebraska groundwater pumping along the river under control. Kansas officials estimated that in drought years, such as Kansas experienced in the late 1980s and early 1990s, Nebraska was using 40,000 acre feet of water more than it should have.

Kansas officials argued their state was losing about 16 percent of the water to which it was entitled under a 1943 compact among the three states. An acre foot of water is equal to an acre of land covered by 1 foot of water; 40,000 acre feet would supply a large city; Topeka uses about 29,000 acre feet a year.

“This adds to the total water supply in the state,” said John Draper, a Santa Fe, N.M., attorney serving as a special Kansas assistant attorney general in water litigation.

Nebraska Atty. Gen. Jon Bruning said the new computer model accepted by the three states “shows who should get how much water and when,” making the compact enforceable.

“Ultimately, Nebraska gave a little, and Kansas gave a little,” Bruning said during an interview. “In a drought, everybody’s going to suffer a little. In good times, everybody will have all the water they need to use.”

In Colorado, Atty. Gen. Ken Salazar’s office said it was pleased with the agreement, noting that it avoided more costly litigation.

Bruning and Kansas officials said the model also gives the three states a way of settling disputes over the river quickly.

“My expectation is that there will be smooth sailing in the future,” Bruning said. “These are the types of things that can be worked out over the telephone, among friends.”

A north fork of the Republican begins in Colorado and flows into Nebraska; a south fork begins in Colorado and flows through northwest Kansas and into Nebraska. After the two forks join in Nebraska, the river flows into north-central Kansas.

The three states reached a settlement in December 2002, and the Supreme Court approved it in May, contingent upon adopting the groundwater model.

The announcement of an agreement on that model came a day after the states finished work on it and submitted it to a special master appointed by the U.S. Supreme Court. The court decides legal disputes among states but typically appoints a special master to hear water litigation.

Kansas officials said the agreement would allow the states to monitor and control water usage so that each claims its fair share under the Republican River compact — 300,000 acre feet a year for Nebraska, 240,000 acre feet a year for Kansas and 40,000 acre feet a year for Colorado.