Crews move young bull trout trapped in pools by dewatering upriver where water remains year round.
Fish out of Water
Scientists think that Kachess River always dewatered to some extent. The timing of Kachess bull trout traveling up to spawn is much later than their relatives in Box Canyon and Gold Creek. However, the extent of dewatering is likely much worse today than it was in the past due to the combination of human impacts and climate change. This means less habitat for young rearing bull trout, who spend 3 to 4 years growing larger before moving to lakes. The process of dewatering takes place rapidly and young bull trout are not strong swimmers. As a result, they become trapped in pools and sections of stream that go dry and they die.
Solving the Kachess Rubik’s Cube
We can’t solve the problem of dewatering entirely since it is tied to the dam. However, we can find ways to retain and create better habitat for bull trout and other species. The first step is gathering information about the upper Kachess watershed. There is a world of possibilities to help bull trout including:
- Placing wood in strategic locations to create refuge during high flows so young fish aren’t pushed down river into the stretch that dewaters.
- Constructing log jams that provide pools with cover that can last throughout the summer for those that are pushed downstream
- Identifying the previous locations of tributaries before they were cut off by the road and reconnect them.
- Identifying relic channels that are lower than the current flood plain and directing flow there
We want to know the most effective ways of restoring the river, and that is where data comes in. Gathering data from gravel counts, ground surveys, LiDAR, flow and groundwater measurements, etc. will direct us where we need to go. For example, LiDAR data will provide us with insights into human impacts over the past 100 years, which we can then correct.
The confluence of Mineral Creek (left) and Kachess River (right). Interesting fact: Mineral Creek contributes significantly more water than Kachess, but is much less utilized by bull trout when spawning.
Kugel, Scott, “ABANDONED MINE LAND IMPACTS ON TRIBUTARIES IN THE UPPER YAKIMA RIVER WATERSHED, EASTERN CASCADES, WASHINGTON” (2018). All Master’s Theses. 939.