WASHINGTON (AP) — Colorado must pay Kansas millions of dollars in damages and interest for depleting the Arkansas River, but not as much as the $62 million Kansas sought, the U.S. Supreme Court ruled Monday.

For years, Colorado farmers dug wells that diverted millions of gallons of Arkansas River water to their fields. Kansas sued its western neighbor in 1985, claiming Colorado violated the 1949 Arkansas River Compact by taking more water than the compact allowed.

A Supreme Court-appointed special master sided with Kansas, then said last year that Kansas was entitled to damages and interest dating to 1969 — an estimated $62 million.

Colorado took exception to the amount, prompting Monday’s order. In a split decision, the court said interest should date to 1985 rather than 1969, when, according to the special master, Colorado should have known it was violating the compact.

Neither side could claim total victory. Colorado objected to paying any interest, while Kansas wanted interest to accrue beginning in 1950.

"The choice between the two dates is surely debatable," Justice John Paul Stevens wrote in delivering the court’s opinion. "It is a matter over which reasonable people can — and do — disagree."

Indeed, Justices Sandra Day O’Connor, Antonin Scalia and Clarence Thomas would not allow any prejudgment interest, while Chief Justice William H. Rehnquist and Justice Anthony M. Kennedy said interest should run from the date on which Kansas sued.

Justices David Souter, Ruth Bader Ginsburg, Stephen Breyer and Stevens agreed with the special master that interest should run from 1969 but endorsed 1985 in order to produce a majority for a judgment.

Still, officials from both states said they were satisfied with Monday’s ruling, which returned the case to Special Master Arthur Littleworth for preparation of a final judgment.

"So few water cases actually get this far," Kansas Attorney General Carla Stovall said. "This court has never awarded monetary damages against any state before, and it has certainly not awarded prejudgment interest against a state before."