By Michael Howell
The Department of Natural Resources and Conservation has scheduled a maintenance and repair project at Painted Rocks Dam this fall that will temporarily interrupt flows from the dam for a few days in early October. The maintenance and repair project is needed in order to complete the repairs initiated this past spring.
According to DNRC water administrator Larry Schock, the department plans to test the gate seals on the outlet tunnel the week of September 30 and make adjustments, if needed, to get the tightest seal possible prior to conducting repair work in the tunnel. Minor flow changes will occur during this period. The concrete repair work in the tunnel is currently scheduled for October 7th through the 10th.
Temporary interruptions of up to 4 hours will occur on the 8th and 9th and possibly on the 10th.
In preparation for the repairs the outflows from the reservoir will be decreased by a series of staged reductions. Based upon the current reservoir inflows, it is anticipated the fall inflows this dry year will be approximately 50-60 cfs. Therefore, reservoir outflows will be reduced to 60 cfs on October 1st, and further reduced to 30 cfs on October 7th before being shut off on the 8th. These staged reductions are designed to allow fish to move to deeper pools, thereby reducing entrapment during the temporary flow interruptions.
After the repairs are completed the outflows from the reservoir will be adjusted to match the reservoir inflows.
Schock said that the maintenance and repair project will not affect delivery of any contract water. Release of contract water from the reservoir will follow its normal course and the contract water should be fully delivered by the end of the water rights legal period of use on September 30th, prior to the shutdown.
Fish rescue planned
According to FWP Fisheries Biologist Chris Clancy, there was some fish mortality reported downstream from the dam following the repairs made last spring. As a result a “fish rescue” has been planned this time around. Clancy is asking for volunteers to come up the West Fork of the Bitterroot below the dam on the days that the water is being shut off and try to rescue any fish that may be trapped and move them to deeper water in pools where they can survive the four-hour shutdown period each day.
“It’s the first time ever that this has been tried in this area,” said Clancy. He said similar efforts have proved somewhat successful elsewhere. He said a lot depends on individual circumstance. Some people have already volunteered.
“We’ll go down there with buckets and nets and maybe some electro-shocking equipment and do what we can,” said Clancy. “There are a lot of unknowns. We don’t know how serious it will be.”
Anyone interested in volunteering can call Chris Clancy at 363-7169.
Public meeting scheduled
A public open house meeting has been scheduled for September 19 to discuss the upcoming repair project at the Bitterroot River Inn and Conference Center at 139 Bitterroot Plaza Drive in Hamilton. The meeting is being held in the Tammany Room on Thursday, September 19 from 6 to 8 p.m. For more information contact James P. Domino at the DNRC State Water Projects Bureau at 406-444-6622.
Fishing restrictions lifted on Bitterroot River
Montana Fish, Wildlife & Parks (FWP) lifted fishing restrictions on the Bitterroot River last Friday, August 30, making it the second river in western Montana to be relieved of restrictions following the initial lifting of the drought-related restrictions on the Clark Fork on August 28. The entire main stem of the Bitterroot River has been closed to fishing from 2 p.m. until midnight since July 25 to reduce the impact on drought-stressed fish. Now water temperatures are holding below the 70 degree restriction trigger.
FWP Fisheries Biologist Chris Clancy said that the restrictions are put in place because catching and handling fish stresses them. Normally it does not have lasting effects and the fish recover quickly. But when water temperatures are high the combined stress can kill a fish.
“High water temperatures are a major factor,” said Clancy. He said that scientists had recognized for some time that the bull trout, which is on the endangered species list, needs colder water than other trout. They begin to suffer at water temperatures of 56 to 60 degrees. So rivers that contain crucial populations of bull trout have a lower temperature trigger than other rivers.
But there is evidence from recent studies, according to Clancy, that may change the trigger in areas crucial to cutthroat trout as well, like the Bitterroot. He said scientists now believe that cutthroat trout may be affected by temperatures as low as 66 to 67 degrees and suffer severely before the other trout are affected.
In 2007-2008, Les Bane conducted a research project comparing temperature tolerance between rainbow and cutthroat trout and discovered that cutthroat reach their tolerance level at about 5 degrees cooler than rainbows. From 66 to 67 degrees is already too much for the cutthroat.
Clancy said that FWP conducted floats on the upper part of the river when temperatures exceeded the 70 degree trigger point last year and this year looking for dead fish. The fifteen-mile trip began on the last three miles of the West Fork and continued another 12 miles on the mainstem.
According to Clancy it is difficult to extrapolate the real number of mortalities from what is observed.
“Fish normally die inconspicuously,” he said. They can get caught between rocks or in vegetation and mud and easily go undetected. He said one thing we do know is that when a number of dead fish are found there are probably more that died and won’t be found.
Clancy said that it has been estimated that cutthroat trout represent about one quarter of the trout population in the river. In July 2012, forty-two dead fish were counted in the float and three quarters of them were cutthroats.
This year four trips were taken beginning in early July and ending the last week of August. In that time it was observed that cutthroat represented three quarters of the trout mortality.
Clancy said special restrictions could be placed in areas critical to spawning and rearing for cutthroats or they could be applied to the whole river.
“We are going to have to look at a little more data and come up with a temperature restriction plan that takes cutthroats into account,” said Clancy.