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Low Flows Hot Trout: Climate Change in the Clark Fork Watershed

Created: 7/14/2008 - Updated: 11/06/2018


Decades of data and observations now point to a clear conclusion: the Clark Fork River basin is now experiencing a very real shift in climate. During the next 100 years, this shift is expected to accelerate, contributing to physical, ecological, social, and economic changes, many of which have already begun.

Scrolling through the months and the metrics from the 1950s, we now see that March in western Montana is hotter, more precipitation comes as rain, spring snowmelt arrives earlier, extreme wildfires are more frequent, and glaciers are making hastier retreats. And the projections years out show much of the same.

While not all the associated impacts are bad—for example, we can expect a longer growing season and improved survival of deer and elk over the winter—we will also experience more forest disease and insect infestation, more wildfire, and higher temperatures in our rivers leading to habitat degradation for our native fish. Some studies have estimated that we could lose between 5 and 30 percent of trout habitat in western Montana over the next century. With less storage of water as snow in the mountains, we can also expect impacts to our “snowpack economy”—agriculture, recreation and tourism, hydroelectric power generation, and forest and range industries.

What does it all mean for our way of life in the Clark Fork watershed? Low Flows, Hot Trout takes a look, delivering a plain-language synthesis of the key findings from years of data-gathering in our watershed, blended with anecdotal observations by a broad spectrum of river basin citizens, from realtor to rancher, fishing guide to firefighter.

We designed this report to be accessible to the public, informative to those whose livelihoods are directly tied to the river, and illuminating to policymakers looking for effective responses.

The bottom line is this: things can be done and everyone can make a difference, from simple at-home fixes that improve energy and water use to large-scale policy changes that stimulate renewable energy production and river-sensitive growth management. The following pages give a snapshot of what we can do to protect our hometown creeks, our local economies, and our celebrated way of life in the changing climate of the Clark Fork watershed.

Published On

Tuesday, July 15, 2008


Regional / Subnational
Sector Addressed: 
Target Climate Changes and Impacts: 
Fishery harvest
Type of Adaptation Action/Strategy: 
Natural Resource Management / Conservation
Capacity Building
Infrastructure, Planning, and Development
Governance and Policy
Habitat/Biome Type: 
Rivers and Streams

Related Resources

Low Flows and Hot Trout: Dealing with the Effects of Climate Change in the Clark Fork Watershed

Photo attributed to US BLM. This work has been released into the public domain because it is a work prepared by an officer or employee of the United States Government as part of that person’s official duties under the terms of Title 17, Chapter 1, Section 105 of the US Code. No endorsement by licensor implied.

Case Study
Sector Addressed: 
Conservation / Restoration
Land Use Planning
Tourism / Recreation
Water Resources

The Clark Fork watershed extends from Butte, MT to Sandpoint, ID and drains nearly the entire western portion of Montana. Based on decades of data and observations, it is clear that the Clark Fork River basin is already experiencing changing climate conditions including droughts, increased wildfires, decreased snowpack, shrinking glaciers, and early runoff.

Protecting the Local Economy from Climate Impacts in the Clark Fork River Basin

Photo attributed to Sooter. Incorporated here under the Creative Commons Attribution-Share Alike 3.0 Unported license. No endorsement by licensor implied.

Case Study

Reverend Maclean explains trout fly fishing to his sons, Norman and Paul, in A River Runs Through It as “an art that is performed on a four-count rhythm between ten and two o’clock.” This art is big business in Montana—the Department of Fish, Wildlife, and Parks estimated that Missoula County alone generated $30.2 million in fishing revenue in 2005.

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