Upper Kachess River Restoration
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 aims to improve migratory, spawning, and habitat conditions for this population this population before they disappear.
Project Details
Date Completed
Phase I was completed summer of 2023
Phase II is ongoing
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 have 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 be naturally recruited into the system was eliminated. Large wood in a river system such as Kachess is essential to river’s proper historic 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 seeks to facilitate the natural recovery of the Kachess River through the:
- Installation of in-stream large wood features to 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 of native vegetation to stabilize soils, shade the stream, and provide cover for the fish.
- Development of new side-channel habitat to provide refuge for juvenile fish during high-flow events (such as spring high flows, or freshets).
- Reconnection of tributaries and the floodplain to recharge groundwater aquifers.
Phase II of the project will relocate the Mineral Creek trailhead and parking area outside of the floodplain and the road to the former parking area will rehabilitated. This will reduce the amount of erosion occurring which transports sediments into the river and lowers overall water quality.
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 | 13,964 |
| Total acres planted | 6.6 |
| Total area seeded with native species | 11 acres |
| Miles of road decommissioned | 2.05 |
| Channel and bank stabilization features created | 32 |
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