How’s the River? With Ken Frazier

How’s The River? – an Interview with Ken Frazier

An Interview with Ken Frazer, District Fisheries Supervisor, Montana Department of Fish Wildlife and Parks October 14, 2009.

Of course, it is always interesting to talk to Ken Frazer about the Big Horn River because he has been so close to it for so many years and cares about the river very much.

The overall impression I got from Ken is that because of the increased flows at critical times over the past three years the river and its fish populations are in good and improving condition.

Although numbers of trout from this summer’s shocking survey have not been worked up Ken reports that it appears the populations in the upper sections (Afterbay to Bighorn Access) of the river have increased. In the lower section of the river (Bighorn Access to Mallards Landing) there are ‘lots’ of young of the year brown trout – But few young rainbows. The lack of rainbows could be a result of the late spawn and lower river temperatures. It is possible that there are good numbers of rainbows but at the time of the survey they may have been too small to capture.

Ken observed that often, depending on the flows, the small brown trout migrate down to the lower reaches of the river and then return upstream as three year old fish.

As many of you know the Corps of Engineers has been conducting a “Side Channel Study”. (The steel posts that have been placed at the inlets to some of the major side channels are a part of the study.) The side channels are very important, not only to spawning, but as places where the small trout can be safe from predators and grow to a size where they can safely move to the main river. One of the outcomes of the study is the suggestion that flows be adjusted during the times of moss displacement (late summer and fall) in order to continue adequate water elevations in the channels to protect the small fish as the seasons pass. This would be a good thing.

Our concerns that we are losing side channel environments in the river are real but the loss of side channel habitat is not as a result of down-cutting of the main river channel. The major cause of side channel degradation is because vegetation has taken root during the low water years and blocked the channels. (Do we need to go to work and open up some of these side channels?)

Mr. Frazer also pointed out that whenever we have the situation of flushing flows as we’ve had for the past two years the make-up and mix of aquatic insects changes somewhat. The high flows remove much of the silt and debris from the river resulting in lower populations of scuds and other mud dwellers. The cleaner river, however, is better environment for species such as stone flies and larger may flies.

In summary, Ken is optimistic about fish populations. In that regard the fish are healthy and increasing in numbers there is a hint of cooperation and understanding of our water flow needs from the Bureau of Reclamation. And the Corps of Engineers study has resulted in a possible plan to better utilize the side channels as rearing areas and therefore more recruitment of small fish into the population.

A Bighorn River System Issues Group meeting was held in Lovell, Wyoming on September 29, 2009.

The agenda included a new management plan for controlling the lake levels by the Bureau of Reclamation based on their latest “rule curve” method of reservoir operations. This new management scheme is supposed to adjust river flows earlier in the year to limit the extreme high flows during runoff.

The BOR also discussed raising the elevation of the conservation pool of the reservoir by five feet to allow for more storage and presented a reallocation study. The Army Corp of Engineers then presented their views in a Flood Pool Reallocation Study to evaluate the change in flood reduction benefits due to reallocation of flood control storage.

The Army Corp of Engineers submitted a Bighorn Lake Sediment Management Study that discussed what might be done to mitigate the effects of the continuing sedimentation of the upper end of the lake. The study has some interesting alternatives to help the problem but all come at very high costs.

The Army Corp of Engineers also presented a Bighorn Side Channel Study that demonstrated the loss of side channels in the river over the years since the dam was built. They emphasized the need for high spring flows to keep open the side channels for young fish habitat.

Lastly, Lenny Duberstein of the BOR demonstrated the effects of moss growth on river stage in the late summer and fall. He stated that the high river elevation created by moss growth early in the fall created additional habitat for young fish. He suggested that lower river flows early in the fall could bank water in the reservoir so that higher flows could be released later in the fall and winter to keep the river elevation at the same level for young fish when the moss growth naturally diminished enhancing the river’s fish production.

The studies and PowerPoint presentations given at the meeting contain much more detailed information, historical and projected data and can be viewed online at: http://www.usbr.gov/gp/mtao/yellowtail/bighorn_longterm.cfm

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