The sounds of machinery and moving rocks fill the air just above an open rock pit as bikers and hikers pass by a University of Montana class. Below them sits the remnants of the Rattlesnake Creek dam, which was recently removed and restored.
The students are in a class called Process Geomorphology - the study of how landscapes look the way they do. It was not a typical classroom setting, but the project paired well with what the students were learning.
“The creation and placement of riffle bars and deeper pools created with log jams in the stream restoration are applications of the quantitative study of these physical features,” senior Nic Gravely, a student in the class, said. “It was really interesting to see how applied geoscience can be used to create a thoughtful and purposeful result through restoration projects like the Rattlesnake dam removal.”
Rob Roberts, a project manager at Trout Unlimited, led the class in the history of the Rattlesnake Creek dam and the process of restoring the area to how it looked before 1904. He is also a graduate from UM.
“We’ve added 10 miles of migration territory for the fish,” he said. “We’re going to restructure this place to the point that in five years, nobody ever realizes there were man made structures here.”
For over 100 years, the three million gallon dam sat on Rattlesnake Creek that served as Missoula’s main source of water, until giardia was found upstream. Missoula then switched to using a different aquifer, rendering the dam useless in 1983.
The dam removal project began in 2017, when the City of Missoula, Montana Fish Wildlife and Parks and Trout Unlimited began the permitting. There are also over 20 private companies in Missoula helping with the project financially.
The deconstruction of the 15 foot by 120 foot concrete dam began in June of 2020.
The next step will be restoring the creek bed to its original state. This process is what Gravely and his class came to observe. The concrete was buried below the parking lot and the rocks are being used as a part of the stream’s restoration, as part of the overflow area. The team will continue to restore the area until their contract ends in late October.
Rattlesnake Creek is a tributary of the Clark Fork River. Its headwaters come out of the Rattlesnake Wilderness Area north of Missoula.
The stress put on fish from the dam is one thing that fishery biologists like Ladd Knotek of Montana Fish Wildlife and Parks take very seriously. It was apparent that fish like Bull trout and the Western Cutthroat are getting stressed due to overfishing and some of the difficulties the dam caused.
“One of the problems that we have with the Clark Fork and some of the other river tributaries around here are recruitment limited, which means that there’s more space available in the river, than there are small fish coming in to fill those spaces below,” Knoteck said. “Another way of saying that is below carrying capacity.”
Knotek said that with the dam removed, it will be easier for fish to make their way up the creek, putting less stress on the fish while rearing and spawning, stages of a fish’s life that are crucial for a healthy river system.
“The bigger issue was [trout] trying to find the entrance to the ladder, because they’re naturally drawn to where the main flow of the stream is,” Knotek said.
Another part to a healthy river system for trout is a complex diversity of trees and deep pools. Before, the dam stopped fallen trees from flowing downstream during high flows. Now, with the dam removed, there is no longer anything to stop them from moving downstream, giving the fish more places to find a home.
If the project continues to go smoothly, both Roberts and Knotek have bigger fish to fry. Currently, there are also 10 other dams in the Rattlesnake Wilderness Area that helped serve the Rattlesnake Creek dam. These dams are hard to access and are also no longer needed.
“We hope to do a pilot project on one dam in the next fews years,” Roberts said. “And if that goes well, there are still nine dams that we will have to deal with. It’s a large body of work.”