Lincoln, Neb. ? Kansas officials say Nebraska owes their state about $9 million for overusing Republican River water in 2005 and 2006.

Nebraska officials submitted documents to an arbitrator in Denver on Wednesday with a much lower estimate of damages — $615,000 to $1.23 million.

The arbitrator is expected to make a decision in June.

Kansas had demanded $72 million from Nebraska. But in December, the arbitrator decided that Kansas can seek payment only for damages it suffered, not payment for what Nebraska gained.

Kansas officials say that if arbitration fails, they’ll take the issue to the U.S. Supreme Court, which issued a decree in 2003 that governs use of Republican River water. The states must announce in July whether they’ll agree to the arbitrator’s decision.

In 2005 and 2006, Kansas says, Nebraska used 78,960 acre-feet — about 25.7 billion gallons — more than allowed under a three-state compact that dictates use of the river. The compact includes Colorado.

That resulted in an estimated loss of crop yield and revenues for Kansas farmers totaling $4.2 million in 2005 and $4.85 million in 2006, according to documents Kansas submitted to the arbiter.

Nebraska disagrees.

In documents the state filed with the arbitrator, it contends overuse of the river was, at most, 71,475 acre-feet — about 23.2 billion gallons. Nebraska said Kansas’ monetary losses are much lower based on a market price for irrigation water in the affected area of $30 per acre-foot.