For years, the Crooked River has been plagued by periodic fish kills. There have been two culprits: sustained low flows, especially when combined with freezing temperatures in the winter, and excess total dissolved gases. TDG is not as well known as low flows but it can be equally deadly. A solution in the form of a new hydroelectric facility may be in the future.
The Crooked River Collaborative Water Security Act (aka the “Crooked River Bill”) was passed in December 2014 to accomplish a number of goals including moving the upper boundary of the wild & scenic section. Previously the boundary was the top of Bowman Dam which creates Prineville Reservoir. Clearly, there is nothing wild about a dam. One of the reasons for moving the boundary a little downstream was to allow for the installation of a “run of the river” hydroelectric facility that would generate power from water already being stored and released. Run of the river means that no releases would be made specifically for the purpose of generating electricity.
The rumor is that Ochoco Irrigation District and the City of Prineville have submitted a preliminary license application to the Federal Energy Regulatory Commission for such a hydro plant. This is a first step in what will be a long process that may not be successfully completed.
Anglers will be happy to know, however, that any major modification to an existing dam triggers Oregon’s fish passage statue. Fish passage at Bowman Dam would be a huge benefit to wild fish but the applicants are likely to ask for a waiver in exchange for providing “mitigation” that would yield a “net benefit” to fish.
One potential net benefit would be to design a hydro facility that eliminated the TDG problem. Bowman Dam was not designed with, nor is it operated with, fish in mind. When Prineville Reservoir fills early in the season huge amounts of water may be released through the dam outlet to lower the level in anticipation of snow melt. Occasionally, water may also go over the spillway. Due to dam design, this water is very turbulent, supersaturating the river with dissolved gasses, especially nitrogen. Nitrogen gas bubble disease is an often lethal condition that has decimated fish populations in the Crooked as recently as two winters ago.
A new hydro facility installed at the base of Bowman Dam could be designed to generate electricity and release water in a much less turbulent fashion. Time will tell but it’s nice to think about something positive happening for fish in one of our local rivers for a change.