| Abstract/Description or Keywords |
The Kootenay River is a transboundary river that flows south from B.C. into Koocanusa Lake, which is the reservoir of the Libby Dam in Montana. After leaving the dam, the river swings northward through Montana and Idaho, re-entering B.C. south from Creston. Just north from Creston, the river enters Kootenay Lake, forming the main inflow to the southern arm of the lake. The Kootenay River near Creston has a drainage area of 36,700 km2 and is used for irrigation and waterfowl conservation, while Kootenay Lake is an important fishery and recreation area. The watershed upstream from Creston has been influenced to varying degrees over the years by the following human activities: a hydroelectric development at the Libby Dam, a kraft pulp mill at Skookumchuck, a mine, concentrator and fertilizer complex at Kimberley, coal mines in the Elk River basin, treated sewage discharges, agriculture, and forestry. CONCLUSIONS: • In an earlier assessment of the data (to 1997), it was determined that there was a subtle trend of decreasing total phosphorus concentrations. This was not deemed a positive thing since fisheries production was declining downstream in Kootenay Lake. From our analysis of data up to the end of 2005, it would appear that this apparent trend no longer exists and the total phosphorus concentrations are stable. • On the other hand, selenium concentrations in the river at Creston appear to be increasing significantly. No such trend can be observed upstream at Fenwick Station, and it has been documented that the human coal mining operations on the Elk River have increased significantly. Although values in the Kootenay River at Creston are not as high as in the Elk River, concentrations are certainly getting closer to guideline values that indicate possible concern for aquatic life. • Dissolved sodium concentrations may also be showing an increase through time. A similar trend that is not as strong is also apparent at the Fenwick station. • All of the apparent trends noted above: stable phosphorus concentrations and increasing selenium and sodium concentrations, need to be confirmed by a statistician. • Temperature generally exceeds guidelines during warmer summer months. • Turbidity values generally exceed the guideline for the protection of source water used for drinking, meaning that if suspended solids removal is not used, disinfection of water supplies could be compromised. • Otherwise, water quality was generally good with only occasional values exceeding guidelines for pH, fecal coliforms, several metals, dissolved organic carbon, and true colour. In cases where total metal concentrations exceeded guideline values, the event generally correlated with higher turbidity concentrations, meaning that the metals were likely in particulate form and not biologically available. RECOMMENDATIONS: We recommend monitoring be continued for the Kootenay River at Creston since it is a trans-boundary site and selenium and sodium seem to be increasing. Water quality indicators that are important for future monitoring are: • flow, water temperature, specific conductivity, pH, turbidity, nutrients, and dissolved oxygen, • phosphorus, sodium and selenium, • appropriate forms of metals for comparison to their respective guidelines, and • other variables related to drinking water such as colour. |
