The Round Butte Hatchery operated by Oregon Department of Fish and Wildlife and funded by Portland General Electric produces both Steelhead trout and spring Chinook salmon smolts. The latter includes a program of re-introduction into the headwaters above the Round Butte Dam, which has been a blockage to migration for several decades.
A recent installation of a gathering device in the forebay of the dam will allow out-migrating smolts to be captured then trucked down river below two other obstructions then liberated to migrate to the ocean. Rearing of fry for release into the upper tributaries requires the water to be depurated with Ultra Violet light.
In order for this to be effective all suspended solids down to ten microns needs to be filtered out of the water. A cartridge filtration system was installed but was costly and still failed to adequately filter out the solids rendering the UV sterilizer ineffective.
The ODFW staff and PGE engineers were intrigued by the concept of flushable sand filters that could accomplish the needed results without the cost of cartridges and the dramatic reduction in labor costs.
Redd Zone staff in collaboration with Natural Solutions of Montana, designed and installed two 250 gallon sand filters in December of 2009. These units are in operation and require only a few minutes each day for the staff to back flush and continue to maintain flows to the early rearing facility that are free of pathogens.
Because of the success of this system, we were asked to return and install filters for the incubation system as well. Both systems are easy to operate and meet the criteria established by the ODFW pathology section. Eggs and fry can now be reared and released above the dam without the fear of IHN and other diseases known to be in the water supply.