Magic Valley irrigators panned them, but eastern Idaho water users overwhelmingly endorsed proposed rules for managing southern Idaho's surface and groundwater as a single resource.

"Take that draft of rules and throw it in the garbage can," Twin Falls attorney Gary Slette, whose firm represents the Twin Falls and North Side canal companies, said Thursday at a state Department of Water Resources public hearing in Gooding."We've got to have some protection, and I urge the department to adopt these rules," Rexburg farmer Dell Raybould said at another Water Resources hearing in Idaho Falls.

Both Slette and Raybould were on the 16-member committee that helped Water Resources Director Keith Higginson draft the "conjunctive management" rules.

Written comments on the proposed rules will be accepted through April 15. They are scheduled to be in place before irrigation demand increases in May.

The rules were already being developed when the Idaho Supreme Court ruled Feb. 28 that Water Resources must distribute water in strict accordance with the state's "first-in-time, first-in-right" doctrine. That means the oldest water rights, primarily surface rights granted in the late 1800s, get first priority when supplies are scarce.

The court ordered Water Resources to deliver water to three Hagerman farmers with historic water rights even if it means shutting down thousands of groundwater wells dug since 1950.

Richard Smith, chairman of the Upper Valley Irrigators Association, said Thursday in Idaho Falls that the proposed conjunctive management rules should be adopted immediately because without them, the Supreme Court decision could cripple groundwater users this summer.

"There is no doubt if the first-in-time, first-in-right doctrine is applied strictly across the board, the effect would be disastrous not only for our members but upon the eastern Idaho economy as well as the Idaho economy in general," Smith said.

But Slette said the draft rules were a radical departure from first-in-time, first-in-right, and he vowed to challenge them in court.

Specifically, he objected to the requirement that surface water users - including his clients - exhaust all stored supplies, drill wells or wait for the transfer of upstream water before being allowed to assert their senior right and force the shutdown of junior users.

But Smith said his group supports the plan's provisions for compensating senior water rights holders because they maintain the idea that groundwater pumpers "should only be responsible for the actual impact that they create."

Several people at the Idaho Falls hearing also applauded Water Resources for upholding the state's "futile call" doctrine. That essentially says it is unreasonable to curtail a junior water right if it will not satisfy a senior right.

However, Wendell-area groundwater pumper Tom Ambrose, also a committee member, said the new rules should be set aside until plans are finalized for recharging the depleted Snake River Plain aquifer with upstream supplies.

In the meantime, Ambrose said no new pumping permits should be granted and all existing permit holders should agree to a voluntary 5 percent pumping reduction.