By Michael Howell
Wade Farrell shed a few tears as he gazed silently upriver at the dam on the Bitterroot River north of Woodside Crossing that had taken the life of Joslyn, his six year old daughter. His sister described the incident. They had been swept over to the right bank of the river in a swift current when they saw a sign warning about the hazard, but it was too late to paddle to the other side. They went over the dam. But instead of moving on they seemed to be at a stand still. Deanna remembers screaming to her brother “Row! Row!” But the boat drifted back to the dam and took on water and flipped over, throwing everybody out.
The current pushes you down and forward, but then curls up and throws you back toward the dam. Engineering consultants would say the dam creates a “hydraulic roller,” others call it a “keeper hole,” and back east they call it a “drowning machine,” according to Leslie Nyce of Montana Fish, Wildlife and Parks. And that’s what it did to Joslyn Farrell that summer day.
The Farrells joined representatives from FWP, the Bitterroot Conservation District, a couple of local legislators and county commissioners at a meeting hosted by Hans McPherson, Chairman of the Supply Ditch Association, for a visit to the site last week. The Farrells became the driving force behind an effort to make the dam safe for recreationists. According to Nyce, FWP knows of eight boating accidents at the dam. But she noted that most boating accidents go unreported.
McPherson said that no one knows exactly when the dam was built. He said that he had pored over about 80 to 90 years of minutes of the ditch company and had not found a single reference.
“We think it was in the 1940’s and possibly built by the Civilian Conservation Corps,” said McPherson. It is a concrete structure forming a perpendicular wall that has some deep scour holes on each side of it.
Molly Skorpik, a civil engineer for Morrison-Maierle, explained how steep walled dams can create a hydraulic roller effect. She said the circular effect of the current can be created by water falling over a steep incline even in low flows and is a dangerous condition.
“The backflow toward the dam can be as fast as 5 to 10 feet per second, whereas an Olympic swimmer can move only about 5 to 6 feet per second at best,” she said.
Add to that the fact that the churning water is filled with air, making it hard to stay afloat, and you have a “drowning machine.”
The situation was deemed so dangerous by FWP last summer that the stretch of river running from Woodside to Tucker Crossing was closed. That decision was contested in court and it was agreed that the river would be re-opened by midsummer and it was. But the hazard remained.
McPherson said that FWP took a big step towards addressing the issue by obtaining a planning grant to do a Preliminary Engineering Report aimed at establishing a remedy. That’s where Skorpik and Morrison-Maierle got involved. After examining options, a preferred design was chosen that involves filling in behind the dam with large stones, grouted in place, to make it a graduated slope, eliminating the hydraulic roll. The work would also include a long sloping boat ramp that could be used by recreationists to float right through.
“But come to find out,” said Skorpik, “rocks are not cheap.”
The total estimated cost of the improvements is $478,362. The Bitterroot Conservation District has applied to the state for a $125,000 grant from the Renewable Resource Grant Program through the Department of Natural Resources and Conservation. This project came out as the number one priority out of 100 applicants in the evaluation project.
“We were praying to be in the top fifty,” said McPherson. “They usually fund the top fifty.”
The Supply Ditch Company is putting up $35,000 cash and $15,000 in in-kind labor. FWP may fork over $40,000 in cash and provide $7,500 of in-kind. Other possible support includes donations form the Recreation Boating Safety Program and the Bitterroot Conservation District. But that still leaves about $145,862 that might come from either private donations or an act of the legislature.
That’s one reason that the local legislators were invited to the meeting.
As Senator Fred Thomas put it, “Our delegation can go back to the legislature and tell them what we have seen firsthand.”
McPherson said that the dam has worked well for the irrigators all these years but when the river shifted to the east five or six years ago, and started bringing all the floaters in this direction, things changed.
“There just wasn’t this kind of use on this stretch of the river before that,” said McPherson. “Now we have to do something to make it safe for recreationists and we are doing our best.”