DEER LODGE – Not many anglers in western Montana have heard of Modesty Creek, but the anglers who like catching fish every year – as in all of them – should be thankful for the obscure stream in the Deer Lodge Valley.
They should also hope there are more Modesty creeks out there.
In September, thanks to a $200,000 restoration project, Modesty Creek was reconnected to the upper Clark Fork River after six decades of total diversion for irrigation.
It’s a success story that benefited not only the health of the fishery and the tourism dollars it supports downstream, but also local farmers and ranchers who cooperated with the effort.
On Tuesday, the Clark Fork Coalition’s stream restoration director, Will McDowell, gave a presentation about how the long-lost creek was finally able to achieve its historic goal of flowing uninterrupted to the main river channel.
Starting in the 1950s, the stream was diverted for agricultural use into a large irrigation canal, severing its connection with the main stem of the Clark Fork.
“This little creek was flowing happily for many, many, many centuries into the river,” McDowell said. “And what this project did was cut off Modesty Creek.”
The canal re-entered the river at a 2-foot drop, meaning it was impossible for fish to access the creek's waters, which were an average of 2 degrees Celsius (3.6 degrees Fahrenheit) cooler and cleaner than the river.
“Wild trout need clean, cold tributaries for food, rest, reproduction and refuge,” McDowell explained. “We need cold water, clean water and connected water. That means tributaries are connected to the main stem throughout the watershed.”
McDowell, who has studied biology and hydrology, said that trout are highly migratory.
“They don’t have a home like you would think about a deer having a home range,” he said. “That’s not the right way to think about fish.”
Trout like to migrate to colder tributaries during the heat of summer to escape high river temperatures.
McDowell said that several studies at Montana State University found that native trout like westslope cutthroat and bull trout are much more sensitive to higher temperatures than introduced species like rainbow and brown trout, which originated in Europe.
Trout also like to spawn in tributary creeks, and smaller juvenile fish use shallower creeks to escape from fully grown predator fish.
“In order for a fish to spawn in these headwaters, the older fish have to move upstream and lay their eggs and the younger fish have to travel downstream to the river,” McDowell explained. “All of that was not taking place because of these barriers.”
McDowell talked with local ranchers who had a stake in the irrigation project, and to his surprise, they were very supportive of his plan to dig a new channel for the creek and have the irrigation come directly out of the main river.
The Montana Department of Environmental Quality and the Montana Natural Resource Damage Program paid for the massive project, which involved lowering the floodplain, digging a new channel with heavy machinery and planting seedlings on the banks.
In September, a trickle of water from Modesty Creek finally hit the Clark Fork River for the first time in 60 years.
“Within one day of reconnecting Modesty, native fish were already accessing its naturally cooler waters,” McDowell explained. “We couldn’t be more thrilled – it’s a good sign that the Upper Clark Fork fishery can rebound in a big way, if we just give it the help it needs.”
McDowell showed pictures of juvenile brown trout and two native species – juvenile mountain whitefish and red-sided shiners – that were caught in the new creek channel within 48 hours of being connected.
Those fish will have a chance to grow into adults, spawn and contribute to the health of the fishery in the river, now that the creek is back to providing a habitat.
“It seems to me that some of the headline grabbers in the world of water tend to be our main-stem rivers and big charismatic rivers that represent power, adventure and the opportunity to catch fish,” said Clark Fork Coalition executive director Karen Knudsen. “That tends to be the Clark Fork, the Blackfoot, Rock Creek, the Bitterroot, the Flathead. But really, those rivers would be nothing without the tiny little feeder creeks that supply the many benefits and aquatic life. And Modesty Creek is one of those that we’ve gotten to know quite intimately over the last few years.”
Modesty Creek is one of eight streams in the Deer Lodge Valley that the Clark Fork Coalition – a Missoula nonprofit dedicated to maintaining and restoring 22,000 square miles of the river’s watershed – is working to improve.
For more information, visit clarkfork.org.