Kootenai River Ecosystem Project
March 8, 2005
According to the U.S. Army Corps of Engineers, the Kootenai Tribe of Idaho, the Idaho Department of Fish and Game and the Bonneville Power Administration propose to add liquid nitrogen and phosphorus to the Kootenai River in Idaho from late June through September each year starting in 2005 in order to improve the aquatic productivity of the river for fish populations.
The Kootenai River downstream of Libby Dam in Idaho is currently nutrient-poor, and has been so for about 25 years. Low nutrient levels are responsible for the low productivity found in the river and part of the reason that important fish populations are not doing well. Nutrients that once flowed downriver from Canada are now being trapped in the reservoir behind Libby Dam. The separation of the Kootenai River from its historic floodplain (downstream of Bonners Ferry, Idaho) has also resulted in less available nutrients for river productivity.
The liquid nutrients would be added through a steel pipe gravity-fed from holding tanks. The proposed location for adding the nutrients to the river is near the Montana/Idaho border. Researchers and river managers would regularly evaluate the effects of the nutrient additions to determine if the project should continue permanently.
The small amounts of concentrated nutrients to be added will be diluted in the river very quickly and will not be harmful to wildlife or people using the river for recreation.
It is expected that positive results from the treatment might be seen within 1-2 months after treatment begins. Algae growth is usually observed within 1 to 2 months after treatment begins. Some fish species, such as whitefish, can benefit within the first year. Most fish species respond after nutrient addition has occurred for some time, usually 2-3 years because it takes a couple of years for the river’s food base (aquatic insects) to increase following nutrient additions.
Water quality will be monitored for nutrient levels. Algae will be monitored for species present and amounts growing in the river. Aquatic insect productivity will also be monitored. Yearly fish surveys will be conducted to help evaluate if the nutrients are working.
Positive outcomes may include increases in desirable sport fish in the river, such as rainbow and cutthroat trout and whitefish. Benefits to white sturgeon, burbot, bull trout, and kokanee growth and population numbers may be additional positive outcomes. Since fishermen would find better fishing opportunities, more fishing interest would in turn benefit local businesses.
Possible negative outcomes could include the formation of algae blooms and increases in nongame fish species, such as suckers. The ecology of the river will be monitored closely to detect undesirable outcomes, and nutrient additions would be stopped should these effects occur.
The Kootenai Tribe of Idaho is the lead agency in this effort. The project is funded by Bonneville Power Administration. The Tribe’s BPA-funded Ecosystem Project has been collecting data and studying the river’s productivity since 1995. The Idaho Department of Fish and Game has been collaborating with the tribe on the project since 2000. Both agencies will work together in the upcoming years to monitor productivity and apply nutrients to the Kootenai River.
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