| Abstract/Description or Keywords |
The Columbia River watershed is located in the southeast corner of British Columbia. Water quality measurements for the Columbia River at Waneta (16 km south from Trail, B.C.) are from samples collected at the Cominco water quality monitoring site from the left bank. The drainage area at this point is 102,852 km2, with the Rocky Mountains to the east and the Purcell Mountains to the west. The river flows in the Rocky Mountain Trench and is used for drinking water, irrigation and industry and supports populations of cutthroat, rainbow, bull, and eastern trout and whitefish. Cirque glaciers in the high Purcell and Rocky mountains drain to the Columbia River and the glacial silt imparts a gray, muddy colour to the river at times. This is alleviated by the time the water reaches Waneta due to the settling provided behind the reservoirs constructed for electricity generation. Water quality in this reach of the Columbia River is influenced by effluent discharges from the Teck-Cominco Metals Smelter and Fertilizer plant, primary-treated sewage from the City of Trail, and secondary-treated sewage from Fruitvale and Montrose, and upstream dams and reservoirs. There are also non-point source discharges from agriculture, urban development, forestry, transportation and stream bank erosion. CONCLUSIONS: _ Turbidity levels in this reach of the Columbia River are very low, due to the settling that occurs behind the hydro generation facilities. _ Several metals that exceeded guidelines on occasion had higher concentrations that correlated with higher turbidity levels. At those times, metals were likely in particulate form and not biologically available. Such metals included aluminum, chromium, copper, iron, lead, selenium, silver, and zinc. _ There appear to be a number of declining trends through time in the Columbia River at Waneta, notably for fluoride, cadmium, iron, lead, phosphorus, zinc and barium. All of these trends, with the exception of barium, were noted in a previous report (Pommen, 2002). Declines in cadmium, fluoride, lead, phosphorus and zinc were at that time attributed to abatement measures at the upstream smelter and fertilizer plant. Decreases in aluminum and iron were potentially at last attributed to trapping effects of upstream dams. The reason for the barium trend, which was also noted upstream at Birchbank, is not known at this time. A number of other apparent changes (decreases) can also be seen, but are believed to be artifacts of decreasing detection limits. _ Water quality in the Columbia River at Waneta would be characterized as being good for both the protection of aquatic life and source waters used for drinking. This is likely due in large part to the settling out of particulate matter behind the upstream dams. There are often measureable fecal coliform counts at the site: water treatment would be required (as in all cases) prior to use as a drinking water source. RECOMMENDATIONS: We recommend monitoring be continued for the Columbia River at Waneta since it serves as the last station on for the Columbia River before it crosses the International Boundary. Water quality indicators that are important for future monitoring are: _ flow, water temperature, specific conductivity, pH, turbidity, nutrients, total dissolved gas and dissolved oxygen, _ appropriate forms of metals for comparison to their respective guidelines, and _ other variables related to drinking water such as colour. |
