After years of water squabbles, a hearing to determine the fate of Magic Valley's groundwater pumpers begins Wednesday that could finally sort out who gets access to Idaho's most coveted natural resource.

The hearing stems from calls by surface spring-water users Clear Springs Foods' Snake River Farm and Blue Lakes Trout Farm. The fish farmers have asked the state to force groundwater pumpers to stop drawing water that the trout farms say is theirs under Idaho's first-come, first-served water law.

The case has a long and tumultuous history. This spring, Idaho Department of Water Resources Director Dave Tuthill was just days from closing pumps - a move that could have crushed Magic Valley's economy - when pumpers offered a last-minute deal that satisfied a previous agreement. But next year, pumpers owe the trout farms 20 percent more water, and Tuthill has already warned the pumpers their wells could be closed in the spring if they can't meet the deal.

The pumpers dispute how much water they owe and say the state's method for allocating water is flawed. The fish farmers say they haven't received their fair share of water in years, and it's costing them millions of dollars. The state hearing, presided over by former Chief Justice of Idaho Gerald F. Schroeder, will sort out the disagreements.

The disputes are incredibly complex and technical, and dozens of engineers, hydrologists and other water experts are expected to testify at the two-week hearing.

Perhaps no one's testimony is more anticipated than that of former IDWR director Karl Dreher, who approved the original agreement between pumpers and the fish farmers. Dreher is expected to testify the first week in December.

After the hearing, Schroeder will make recommendations to Tuthill, who has final say. But most close to the case expect the outcome to be challenged in court, regardless of Tuthill's decision.

Either way, one of the groups - both major economic drivers in Magic Valley - likely stands to lose big without access to water. Fish farmers say they'll continue to lose millions. Irrigators say they could go out of business and cripple the agriculture industry.

Matt Christensen may be reached at 735-3243 or at matt.christensen@lee.net.