| Abstract/Description or Keywords |
The Kootenay River is 780 km long and stretches from the Rocky Mountains in southeast British Columbia through the U.S. before re-entering Canada and draining into the Columbia River at Castlegar. The Kootenay watershed drains an area of 50,300 km2 and is an important power generating river. Major lakes in the watershed include Kootenay Lake and Lake Koocanusa. There are currently five Canada-B.C. water quality monitoring stations located in the Kootenay watershed: the St. Mary River at Wycliffe, two sites on the Kootenay River located at Fenwick and at Creston, and two sites on the Elk River at Hwy 93 and Sparwood. Another surface water quality monitoring station at the Moyie River at Kingsgate was deactivated in the spring of 2009. Upstream impacts are diverse and vary, but well-known impacts include coal mining in the Elk River basin while the St. Mary River watershed includes a closed mine and fertilizer plant. Water uses include but are not limited to aquatic life, recreation and drinking water. This report assesses water quality data collected from these sites over a broad timeframe. The sample period for each site varies, and data from the Elk River at Sparwood were not tested for trends due to the relatively short timeframe of the sample set. Flow (mean daily discharge) measurements taken from various Water Survey of Canada sites were used to describe seasonal flow patterns. CONCLUSIONS: _ Water quality in the Kootenay River mainstem was typically good with very few parameters that consistently exceeded relevant guidelines; parameters that exceeded guidelines were often driven by seasonal turbidity spikes as a result of freshet and generally not considered a concern. _ Water quality in the St. Mary River are generally stable or improving, likely as a result of the closure and waste abatement at the Teck Cominco mine and the closure of the fertilizer plant located upstream of the water quality monitoring site. _ Certain metals, specifically cadmium and zinc, do not correlate well with turbidity suggesting that exceedences are partly driven by dissolved concentrations of these parameters. Dissolved measurements should be analysed in addition to total for these parameters. _ There continues to be numerous deleterious trends and water quality issues with the Elk River: total (slope = 0.1 _g L-1 yr-1) and dissolved selenium (slope = 0.2 _g L-1 yr-1) continue to rise and consistently exceeds CCME and BC aquatic life guidelines; nitrogen (as NO3+NO2) is increasing at a rapid rate (slope = 0.01 mg L-1 yr-1) and may impact downstream lentic systems; and sulphate continues to increase in this system (slope = 0.47 mg L-1 yr-1) but is still below aquatic life guidelines. There are a variety of other water quality trends associated with this site, although these are not immediate concerns. _ There was a slight increasing trend in total phosphorus at the Kootenay River at Fenwick station. This increase, in combination with increasing nitrogen inputs from the Elk River, may lead to more frequent and unwanted algal blooms in downstream lentic systems; downstream data was not available to assess algal growth. _ The Kootenay River at Creston has numerous trends which appear to be associated with Elk River inputs including slight increases in total selenium, and increases in alkalinity and total hardness. _ Fecal associated microbiological measurements are significantly increasing along the Kootenay River mainstem. _ Water temperatures seasonally exceed daily maximum guidelines for the protection of bull trout, the most sensitive species in these systems. These seasonal exceedences appear to be common throughout the datasets. Recently installed continuous temperature loggers should allow for the determination of the intensity and duration of these exceedences, and trend detection, should any exist. RECOMMENDATIONS: It is recommended that water quality monitoring stations located on the Kootenay and Elk rivers continue to operate to monitor changes in the Kootenay watershed due to upstream influences such as coal mining. It is recommended that algal growth be monitored at lentic sites below the Elk River to determine the effect of increased nutrient loads. Consideration should be given to the establishment or reactivation of hydrometric stations near the Elk River at Hwy 93 and the Kootenay River at Creston to allow for loading calculations. In addition to total metals, dissolved metals should be monitored at all sites for guideline comparison. Also, tri- and hexavalent chromium should be monitored once suitable sampling and analytical methods are established for guideline comparison. Finally, sulphate should be monitored at both Kootenay River monitoring stations to assess the impact of sulphate concentrations from Elk River. |
