Beavers land on the hot seat in Idaho

  • Beavers: Within easy reach of the long arm of the law

    Robert Hilgenfeld
  Idaho farmers who suspect beavers are damming water that could be irrigating their fields can call on state officials to throw the beavers out - even when their dams are on private property. Idaho Gov. Phil Batt signed the bill in mid-March.

The legislation grew out of a dispute between two groups of property owners near the Big Wood River, south of Sun Valley. Three ranchers with water rights from the Broadford Slough along the river blame a beaver pond located on private property upstream for taking irrigation water during drought years. Doubtful that local efforts could resolve the issue, one rancher asked his attorney to solve the problem with legislation.

The attorney drafted a bill that requires the state Department of Water Resources to investigate complaints about beaver dams and determine whether dams are affecting water rights. If so, the Department of Fish and Game is authorized to enter any land to modify or destroy the dams.

"We haven't decided yet how we're going to approach it," says Ken Norrie, assistant director of the Department of Fish and Game. "The main thing we're concerned about is that it puts our employees in a tough position. There is an anti-government feeling in the state and throughout the country. Doing this isn't going to help that any."

"One week they're talking about the overbearing state and federal officers and jackbooted thugs, and the next week they say you can trespass on private property," complains another Fish and Game Department officer.

Some bill proponents pitched it to the legislature as a remedy for newcomers' attempts to impose their aesthetic values on Idaho's traditional uses of its resources - in this case, that beautiful beaver ponds are more important than downstream irrigation. Such a conflict has indeed been developing in the state over the past few decades, especially in resort areas such as Sun Valley. But both of the property owners seeking to maintain the controversial beaver pond claim deep Idaho family roots.

The dispute over the new law centers on the ecological effects of beaver dams. Lynn Tominaga, water analyst for the Idaho Water Users Association, says that by holding back water, beaver dams allow water to percolate downward into the groundwater table, making it unavailable to properties immediately downstream.

"I can't buy that unless the pond is really quite deep," counters Harold Jones of the Idaho Department of Water Resources. Jones says most beaver ponds are not deep enough to generate enough pressure to force the water through the ponds' accumulation of sediment.

The contention that ranchers' lose water from beaver ponds through evaporation appears more substantial. Jones says evaporation amounts to about one acre-foot of water, or 365,000 gallons, per acre of pond per year. Tominaga says a southern Idaho farmer normally uses 2.5-3.0 acre-feet of water a year for each irrigated acre.

But beaver ponds also help farmers. In dry years, the water stored in them may provide an extended watering season, according to a memo written by a Fish and Game biologist analyzing the bill. The ponds actually spread out valuable nutrients and are "probably the main reason why Broadford Slough is a fertile farming area," the biologist concluded.

Despite the apparent heavy-handedness of the recently passed legislation, people on both sides of the issue say they are willing to cooperate.

"If it's proven that there is a water loss, we'll do whatever it takes to correct that," says one property owner near the Broadford Slough beaver pond.

The landowners have proposed installing culverts that would allow the water to be discharged from the ponds when it is needed downstream.

Tominaga says he hopes the bill will act as a means of providing scientific determination, rather than guesses, about the effects of beaver dams on water supplies.

"Hopefully," he says, "the director (of the Department of Water Resources) will base his decisions on facts, not biases."

* Greg Moore

The writer works out of Ketchum, Idaho.

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