Restoring Salmon Fishery

University of Idaho researchers are helping the Schitsu’umsch (Coeur d’Alene) Tribe create a blueprint for restoring a culturally important former salmon and steelhead fishery that’s become channelized, sediment-filled and warm.

Hangman Creek was once the only place within Schitsu’umsh Reservation boundaries where tribal members could catch anadromous fish, which migrate up rivers from the ocean to spawn. According to an account from 1873, Hangman used to be so loaded with Chinook salmon and redband steelhead that they blocked the view of the streambed.

Now Hangman supports only a small, resident redband population, as most of its reaches have been degraded by decades of private owners, straightening the creek and disconnecting it from its historic floodplain to expand cropland. Engineered structures like dams and culverts also alter historic fish migrations.

The tribe secured a one-year, $250,000 planning grant through the National Fish and Wildlife Federation’s America the Beautiful Challenge to identify highly erodible areas contributing sediment into the creek and plan site-specific solutions. The tribe will be collaborating with scientists from U of I’s College of Agricultural and Life Sciences (CALS) — Erin Brooks, Mariana Dobre and Laurel Lynch, all faculty within the Department of Soil and Water Systems.

The tribe is also researching the use of biochar to raise water levels in the stream through its participation in the CALS-led Innovative Agricultural and Marketing Partnership for Idaho (IAMP). IAMP, funded with a five-year, $55 million grant through the U.S. Department of Agriculture, incentivizes farmers throughout Idaho to adopt designated climate-smart agricultural practices. Biochar, made by burning fuel at high heat and low oxygen, is known to increase the ability of soil to absorb and retain water, while also lending nutrients. About 14 truckloads of biochar will be spread this fall throughout 50 acres of the tribal farm, and the tribe will install sensors to work with U of I on measuring how applications affect soil carbon and greenhouse gas emissions. The project will also evaluate how biochar affects farm productivity.

The tribe acquired the biochar from an outside supplier but has purchased a mobile biochar production system, called a CharBoss, to begin making biochar from slash piles left by forest thinning on the reservation.

“There was a double opportunity to engage in practices that are going to help those producers be more resilient in the face of increasing drought and heat, but also encourage practices that are going to rebuild a lot of the loss of topsoil, sediment and nutrients on the landscape and be in better harmony with water quality and our fishery-restoration objectives,” said Laura Laumatia, environmental programs manager with the Schitsu’umsch Tribe.

For the America the Beautiful Challenge work, U of I researchers will implement the U.S. Department of Agriculture’s Water Erosion Prediction model (WEPPcloud), which was developed for agricultural land but has been adjusted by U of I for predicting erosion on forested land. Hangman, which contains both agricultural and forested reaches, is the major contributor of sediment into the Spokane River, which flows into the Columbia River. Modeling results will help the tribe establish priorities for its Salmon Plan as it seeks to strategically purchase erodible properties and implement solutions aimed at keeping sediment out of the stream.

“With the modeling component, we hope to identify hillslopes currently in crop production that generate higher levels of erosion,” Dobre said. “Once these problem areas are identified, the tribe plans to decommission some of them and possibly change the land cover from agricultural crops to culturally significant vegetation.”

Researchers plan to install water monitoring instruments this fall to measure dissolved oxygen, temperature, water quality and other factors that will help calibrate the model, along with measurements from an existing U.S. Geological Survey stream gage. Lynch will oversee the field work, including taking soil samples starting next spring as a baseline for tracking soil-health improvements over time.

The model can also simulate the potential for erosion based on anticipated long-term changes in climactic conditions.

“The majority of erosion in a watershed often happens from a minority of the land. It could be that 90% of erosion happens from 20% of the landscape within the watershed,” Brooks said. “Targeted management to reduce erosion is a good strategy.”

The tribe’s Fisheries and Wildlife Program began efforts to restore Hangman nearly three decades ago, acquiring important land as it becomes available and restoring riparian areas to replenish spring flows into the creek by reintroducing beavers and installing manmade beaver dams. The tribe intends to pursue another grant from the National Fish and Wildlife Federation to implement additional solutions.

A second prong of the tribe’s strategy to bring back anadromous fish has been pursuing grants to support releasing hatchery-bred Chinook salmon. Following the release of juvenile Chinook into Hangman in 2021, two of the tagged fish made it to the Pacific Ocean and returned two years later to the first dam on the Columbia River. One of those fish was transported to Hangman to complete its migration.

“The journey of that fish I think was an inspiration and really paved the way for a lot of bigger support for fish restoration in the Upper Columbia,” Laumatia said. “It was part of the realization that Chinook are incredibly resilient. They are sensitive to temperatures, but they want to be home.”

For now, the Schitsu’umsch Tribe and U of I will focus on making Hangman a suitable place for a homecoming.

Published in Catching Up with CALS