Feds weigh options to deal with Hyatt Dam seepage

ASHLAND — Federal water managers are mulling whether to address growing seepage through a portion of Hyatt Dam with structural fixes or by keeping Hyatt Lake's water levels more than one-third lower to ensure dam safety.

The federal Bureau of Reclamation is in the early stages of flushing out the ramifications of either option to deal with the seeping water, which is deemed to have the potential for structural damage. The problem was discovered during a 2009 inspection of the 53-year-old dam in the Greensprings east of Ashland.

Options include putting filters inside the earthen and rock-filled structure so water would pass through the often-leaky dam without threatening its structural integrity, according to the bureau.

That's how the bureau dealt with seepage problems in the 1960s and 1980s.

Another option would be to drop the reservoir's maximum elevation to a foot below the seepage point along the upper portion of the dam's southeast corner, according to the bureau. That move that would reduce the lake's 16,200-acre-foot capacity by about 6,000 acre-feet, bureau statistics show.

That's a total volume between what fills Agate Lake near White City and the full capacity of Fish Lake along Highway 140 near the Klamath County line.

The bureau is now studying potential economic impacts from reduced capacity on everything from bank stabilization to irrigation losses and recreation impacts, said Chris Regilski, the dam safety coordinator in the bureau's regional office in Boise.

The various filter options likely would cost between $2 million and $3 million, Regilski said.

Manager Jim Pendleton of the Talent Irrigation District, which manages the reservoir's irrigation water, said losing that potential storage capacity likely would not harm TID ability to meet its patrons' needs during normal or wet years.

However, it would limit TID's potential volume of carryover water for future dry years, which is the main purpose for the reservoir's existence, Pendleton said.

"Certainly the district would prefer to spend that money and fix it so we have that storage available," Pendleton said.

Pendleton said he believes the structural solution would be cheaper than economic losses from reduced capacity.

"I think there are hidden costs on reservoir restriction that would have to be borne out," Pendleton said.

The bureau is scheduled to select its favored solution in April, then present it publicly in May, Regilski said.

If a structural change is chosen, work would be scheduled for 2016, Regilski said.

Hyatt, along with Howard Prairie and Emigrant reservoirs, are part of a three-tiered system for feeding irrigation water through TID and the Medford and Rogue River Valley irrigation districts.

Under the current formula for paying for future work at Hyatt Dam, 85 percent of the costs would be covered federally, with the districts picking up the remainder.

At over 5,000 feet above sea level, Hyatt's ability to draw on high-elevation snow helps make it TID's ace in the hole during dry years. Also, because of limited canal size and other restrictions at Howard Prairie, Hyatt outflows can be more aggressively altered to control water levels in Emigrant Lake near the valley floor.

"That's my workhorse," Pendleton said.

TID built the original Hyatt Dam on Keene Creek in the early 1920s. It was taken over by the bureau in 1960 and immediately rehabilitated.

Reach reporter Mark Freeman at 541-776-4470 or mfreeman@mailtribune.com.

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