Flathead Lake: Water Quality and Limnology
Flathead Lake is the largest natural freshwater lake in the western US, and one of the cleanest large lakes in the world. However, its world renowned water clarity and ecological health continue to be threatened by human-caused increases in nutrients and sediments, as well as the potential arrival of new Aquatic Invasive Species.
The FLBS record of research began in 1899, the year FLBS was founded, when Dr. Morton J. Elrod initiated the first scientific investigations of the lake. FLBS has remained the “Sentinel of Flathead Lake” ever since.
In 1977, in response to threats of large-scale coal mining in the North Fork Flathead River in British Columbia, Canada, FLBS instituted a scientifically rigorous water quality research and monitoring program and now has one of the best long-term continuous datasets in the world for a large lake and river system.
Our regular (roughly monthly) monitoring program provides a clear, consistent record of physical, chemical and biological lake characteristics and changes over time, and reveals threats before they become problems. Our scientific data, especially pertaining to nutrients, have been used by state and federal agencies in the development of water quality standards via the Clean Water Act’s Total Maximum Daily Load (TMDL) process.
Our research continues to address cutting edge questions about the ecological conditions of the lake. For example in 2012, FLBS researchers installed a network of telemetered environmental sensors (weather and water quality) to enhance the resolution of knowledge of lake conditions. Currently FLBS scientists are utilizing this data in concert with the long-term dataset to drive a lake model that will help predict future conditions in the lake related to changes such as increasing temperature, the arrival of new species and the removal of existing ones (e.g., lake trout).
FLBS research and expertise regularly help managers and politicians make informed decisions that have resulted in significant water quality conservation successes, including a ban on Phosphorus-containing detergents, the upgrade of watershed sewage treatment systems, and the prevention of mining in the North Fork Flathead River.
Maintaining the high quality of water that many people in the Flathead Valley take for granted does not come without effort. If you would like to help with efforts to maintain Flathead water quality now and for future generations, visit the FLBS charitable giving page
- Elrod, M. J. 1901. Limnological investigations at Flathead Lake, Montana and vicinity, July 1899. Transactions of the American Microscopical Society 22:68–80
- Elrod, M. J. 1929. The fishes of Flathead Lake. Montana Fish and Game, Helena, 11.
- Stanford, J. A. and D. S. Potter. 1976. Limnology of the Flathead Lake-River Ecosystem, Montana: A perspective. Ecological Society of America, Eastern Washington State College Press, Cheney. 241–252 pp.
- Ellis, B. K. and J. A. Stanford. 1988. Phosphorus bioavailability of fluvial sediments determined by algal assays. Hydrobiologia 160:9–18.
- Spencer, C. N. and B. K. Ellis. 1990. Co-limitation by phosphorus and nitrogen, and effects of zooplankton mortality, on phytoplankton in Flathead Lake, Montana, USA. Verh. Internat. Verein. Limnol. 24:206–209.
- Spencer, C. N. and B. K. Ellis. 1998. Role of nutrients and zooplankton in regulation of phytoplankton in Flathead Lake (Montana, USA), a large oligotrophic lake. Freshwater Biology 39(4):755–763.
- Ellis, B. K., J. A. Stanford, D. Goodman, C. P. Stafford, D. L. Gustafson, D. A. Beauchamp, D. W. Chess, J. A. Craft, M. A. Deleray and B. S. Hansen. 2011. Long-term effects of a trophic cascade in a large lake ecosystem. Proceedings of the National Academy of Sciences USA 108(3):1070–1075.