Upper Kachess River Restoration

Completed November 2025

When settlers constructed dams in the upper Yakima Basin without fish passage in the early part of the 20th century, lake and river ecosystems were profoundly impacted. One species that was particularly affected was bull trout. These dams isolated headwater populations of bull trout from one another on a local and regional scale. Furthermore, the dams stopped salmon, an important food source for bull trout, from returning to these systems. Many of these bull trout populations, including the upper Kachess River population, are in decline. To this end, this project aimed to improve migratory, spawning, and habitat conditions for this population before they disappeared forever.

Project Details

Date Completed
Phase I Completed Summer, 2023

Phase II Completed November, 2025

General Area

Upper Kachess River Floodplain near Mineral Creek Trailhead

Funding $ 4,042,998.00 Outcomes Improved habitat for bull trout

Project Objectives

More than a century of landscape modifications for water storage, logging, mineral extraction, and recreational development had altered the geomorphological and ecological processes of the Kachess Watershed, leaving it in a degraded state. The mature old growth forest that occupied the historic Kachess River Valley was clear cut, and large wood that would have been naturally recruited into the system was eliminated. Large wood in a river system such as Kachess is essential for supporting proper ecosystem function. Prior to KCT’s restoration, Kachess River suffered from:

Poorly established riparian zones
Eroding stream banks
Lack of in-stream complexity (i.e. large wood, deep pools)
A disconnected floodplain and tributaries
Insufficient juvenile refugia (i.e. side channels, deep pools, woody cover)
Recreation impacts causing degraded water quality

This project worked to facilitate the natural recovery of the Kachess River through the:

Installation of 61 in-stream large wood features that dissipate high energy flows, reconnect floodplains and tributaries, stabilize stream banks, and provide essential habitat for migrating and rearing Bull Trout.
Creation of deep, groundwater fed pools to provide cold water refuge for fish during low flows.
Planting 7 acres of native vegetation to stabilize soils, shade the stream, and provide cover for the fish.
Development of nearly 1,000 feet of new side-channel habitat to provide refuge for juvenile fish during high-flow events (such as spring high flows, or freshets).
Reconnection of 13 acres of tributaries and floodplain to recharge groundwater aquifers.

Phase II of the project relocated the Mineral Creek trailhead and parking area outside of the floodplain, and the road to the former parking area was partially decommissioned and modified to reduce sediment delivery into Watermelon Creek (a tributary of Kachess River). This reduction of erosion and sediment transport will help improve water quality in not only Watermelon Creek, but Kachess River as well.

Project Outcomes By the Numbers

Miles of in-stream restoration	1.0
Large wood structures installed	61
Pieces of large wood added to channel	1,441
Scour holes connected to groundwater created	21
Acres of main stem and adjacent riparian/banks treated	19
Acres of floodplain activation, tributary connection, and side channel creation	13
Native plants planted	14,624
Total acres planted	7
Total area seeded with native species	13.63 acres
Miles of road decommissioned	2.15
Channel and bank stabilization features created	32
Trailheads Moved/Rebuilt	1