Summer has arrived with a vengeance in the Bitterroot Valley and people are flocking to the river to keep cool. But the river is a dangerous place during high water and the bridges over the river, which serve as main access points, also pose dangers of their own for pedestrians, bicyclers and drivers. A young boy was seriously injured a few weeks ago while riding his bicycle over the bridge at Woodside which lacks a pedestrian or bicycle lane. A six-year-old girl recently drowned in a boating accident at a dam that poses a serious hazard to floaters.
The drowning and several other close calls requiring rescue occurred at a Bitterroot River diversion dam, located approximately three miles downstream of the Woodside Crossing Fishing Access Site (FAS). Faced with this tragedy and other drownings on other rivers in the state in recent weeks, Montana Department of Fish, Wildlife & Parks is urging floaters to use caution and watch for river hazards,
Pat Saffel, FWP Region 2 Fisheries Manager, says that rivers are dynamic and water levels can change frequently. Changes in water flows mean that risks posed by these obstacles—like diversion dams, log jams and rocks—also change. “Be on the lookout for these obstacles, take it slowly, and when in doubt, stop and scout the water conditions. If you need to, walk yourself and your boat around obstacles,” Saffel says.
In the case of the Bitterroot diversion dam between Woodside Bridge and Tucker Crossing FAS, FWP tells those that float this stretch of river to walk boats (portage) around the dam. FWP urges boaters to familiarize themselves with the dam’s location before their trip and to watch for warning signs at upstream access sites and along the river that warn of the dam and point to the portage location.
Saffel said that FWP has been aware of the “back boil” problem at the dam for some time and had put up warning signs on the river near the dam in 2011. He said that there was no indication that the signage was insufficient. He said the recent rash of accidents at the site was unique. As a result, more and larger signage was being installed and the portage route was being made easier to identify.
“The responsibility is with the floater,” he said, “but we are doing what we can to keep people safe.”
Saffel says that FWP is interested in looking at long-term solutions for boater passage at the site, but for now boaters need to carry their boats around.
“If you’re not comfortable carrying your boat around this particular diversion dam, we urge you avoid this stretch of river,” says Saffel. “There is a good spot to portage around the dam, and we want all river users to be aware and to use it.”
Small low-head dams, like this one and others on the Bitterroot and elsewhere, are built to back up water, often for irrigation purposes. Because of their small size, they often do not appear to be dangerous, especially when viewed from a boat or canoe upstream, but water pouring over the dam creates a churning backwash or current. This “hydraulic,” as it is often called, is really a recirculating current.
The rolling water can take any object (including a person) to the bottom of the stream, release it to the surface, suck it back to the face of the dam, and push it back to the bottom. This cycle can continue indefinitely. [Watch simulation of diversion dam hydraulics]. Branches and other debris trapped in the hydraulic pose an additional hazard to the victim. It is hard to stay afloat, even if wearing a life jacket (PFD).
Saffel said that the agency was working with the irrigation company to come up with a permanent resolution that will eliminate the “back boil” at the dam and possibly allow a pass through section for floaters.
“As you go to the water to cool off on this weekend and over the next few weeks, we want you to have fun out there but to have water dangers and safety precautions on the front of your mind,” Saffel says.
For more on staying safe in the outdoors, go to the FWP website at fwp.mt.gov on the Recreation page, click on Stay Safe Outdoors.