Impact on the Crooked River

The proposed Deschutes Basin Habitat Conservation Plan includes a section on the Crooked River (see pages 34 to 37).  While I have heard some in the angling and conservation communities speak favorably about the proposal for the Crooked, I am not in agreement.

In summary, my concerns are:

  • There is no scientific justification for the 50 cfs average minimum target during the winter and it is unclear what is meant by “average”.
  • There is no provision for reducing the incidence of gas bubble disease.
  • There is no mention of water quality.
  • It does not address the low flow, high temperature problem that exists below the Wild & Scenic section during irrigation season.

In a good water year Prineville Reservoir fills completely and at least half of the water is released during irrigation season.  This water stays in the river through the popular eight mile long Wild & Scenic section below the dam after which irrigation diversions commence.  Due to these irrigation releases, the Wild & Scenic section is typically well watered from the spring through the fall.

Even during irrigation season, however, the Crooked is only healthy for a short stretch.  After the Wild & Scenic section, irrigation diversions gradually reduce the Crooked to a small, overly warm river. The North Unit Irrigation District canal a little past Prineville is the final major diversion, although smaller diversions occur below that.  Even during irrigation season, low flows and high temperatures make the Crooked largely unsuitable for salmonids (resident trout and whitefish as well as reintroduced and endangered steelhead and salmon) below the Wild & Scenic section, especially from the NUID diversion down to Crooked River Ranch where the river is refreshed by groundwater springs.

The proposed HCP does nothing to address the low flow, high temperature issues.  At a minimum, flows down to the confluence of Ochoco and McKay Creeks should be improved for resident fish habitat, flows all the way to Lake Billy Chinook need improvement at times to support anadromous and endangered fish reintroduction.

Anglers are more familiar with problems from low winter flows which have sometimes been reduced to a trickle, killing fish and exposing the river bottom which in turns kills the aquatic insects fish eat.  Per federal legislation, about half of water storage capacity in Prineville Reservoir is to be released for “the maximum biological benefit of fish”.  During good water years there is ample water available for release to keep the river healthy in the winter, the problem is low water years.

The proposed HCP addresses this by stating that a portion of the “uncontracted storage” (aka, “fish water”) will be held until the end of irrigation season along with additional water controlled by the City of Prineville.  The goal is to maintain at least 50 cfs of release into the Crooked during non-irrigation season.  In good water years this should not be a problem as modeling has shown that 80 cfs could be released through the winter.

In extreme dry years when the reservoir does not completely fill there may not be enough of the “fish water” to maintain 50 cfs through the winter.  In this scenario, Ochoco Irrigation District has agreed to release enough of their allocation to meet the 50 cfs target.  This commitment is the reason that some believe the proposed HCP is good news for the river, but I am not as sanguine for three reasons:

  • I am concerned about the language in the proposal which states that water will be “released at a daily average rate of 50 cfs”. A release of 25 cfs one day and 75 cfs the next day will give a daily average of 50 cfs but a flow of 25 cfs on just one freezing day will significantly harm the river.  Or, perhaps, this language is intended to mean that during a single day the average will be 50 cfs.  That is not much better.  A flow of 25 cfs for a few hours on a freezing day will still kill much of the river.   We humans need to breathe every second of the day, not just most of them, and we certainly can’t be exposed for long to freezing temperatures without clothing or shelter.  The same goes for aquatic life.
  • More importantly, where did the 50 cfs target came from? What is the scientific basis for this number?  USFWS wrote a biological opinion on the needs of the upper Deschutes, where is the opinion for the Crooked River?  The Oregon Department of Fish & Wildlife has stated that the Crooked needs more than 50 cfs for fishery health. Hardin 1993 Summary report – Crooked River instream flow study
  • Finally, it must be made clear that 50 cfs is the absolute minimum and only in extreme dry year scenarios, which must be clearly defined. 50 cfs should not be a normal winter target.  Higher targets must be established for normal water years and rules established for violating them.

Remember that the purpose of the HCP is to create a habitat that supports endangered species (steelhead and salmon).  I have not seen any science stating that 50 cfs is all that is needed in the winter.  Similarly, I have not seen the science that says warm, low flows downstream of the Wild & Scenic section is viable habitat during the summer.

Another point of concern is the lack of any high flow targets.  While everyone understands that fish need minimum water levels, high water levels are also problematic.  When the reservoir is allowed to fill too quickly significant amounts of water must be released to ensure dam integrity.  High flow releases create a condition called nitrogen gas bubble disease, a far too frequent problem on the Crooked.

Nitrogen gas bubble disease occurs in water supersaturated with nitrogen or oxygen. On the Crooked this comes from the turbulence created by high flows over the dam spillway. Fish breathe the supersaturated water and are unable to metabolize the excess gas, forming bubbles on their skin.  In severe cases damage to organs, the brain, and death may occur.

Another important omission from the HCP is a discussion of water quality.  Improved flows are only one part of better habitat.  Agricultural runoff into the Crooked River is a significant source of pollutants both in the Crooked and downstream in Lake Billy Chinook.  These pollutants impact endangered species like steelhead and salmon returning to the Crooked as well as endangered bull trout in Lake Billy Chinook.  Runoff comes from OID patrons, farms along the river, as well as from Central Oregon Irrigation District runoff.  There is significant overwatering and runoff from COID patrons near Powell Butte and around Ranch at the Canyons.  The complete lack of any mention of improved water quality is a significant omission from the proposed HCP.