| Abstract/Description or Keywords |
The Moyie River is located in southeast B.C. and drains into the Kootenai River in Idaho before re-entering B.C. as the Kootenay River. The watershed is used for fishing, recreation, irrigation, and domestic and municipal water uses. Forestry and some agriculture are the main anthropogenic influences. The hardness in the Moyie River is typically low which suggests that it would be sensitive to metals that might be discharged (even at low levels) should mining occur in the basin. This report assesses 11 years of water quality data from the Moyie River at Kingsgate over a period from 1990 to 2007. The water quality station is located 0.5 km upstream from the border and has an upstream contributory drainage area of 1,480 km2. Water quality samples were collected once every two months until the station was suspended in 1995, and then collected monthly when the site was reactivated in 2003 as a federal-provincial water quality monitoring program station. Flow was monitored on the Moyie River at Eastport on the Canada-US border by the Water Survey of Canada. CONCLUSIONS: _ Moyie River water quality was generally good, with a small number of transient seasonal spikes in certain parameters that were related to increased flow and turbidity. _ Total aluminum concentrations exceeded the B.C. guidelines that are expressed as dissolved concentrations of the metal on a seasonal basis. _ Total cadmium concentrations exceeded the B.C. and CCME aquatic life guidelines during freshet, but were near or below guidelines during base-flows. _ Total iron and total lead exceeded aquatic life guidelines during freshet, but these exceedences were related to high turbidity values and not likely bioavailable. _ E.coli and fecal coliforms were measured since 2003 but the sampling frequency did not meet requirements for assessing guideline compliance. Although there were occasional spikes over the sample period, median values were generally low. However, visually it appears as though E.coli and fecal coliform measurements were increasing over the sample period. Filtration and disinfection would be required in advance of drinking water use. _ Alkalinity measurements suggest that the Moyie River is moderately sensitive to acid inputs, and total hardness measurements classify the river as a soft water system. This suggests that the Moyie River may be sensitive to mining, should it occur within the watershed. _ A number of metals need to be measured differently if comparisons are to be made to guideline values as these exist. The metals and forms required to be measured are aluminum (dissolved and inorganic monomeric, when available), chromium (trivalent and hexavalent, when analyses are available and reliable), and iron (continue to measure total but also dissolved). RECOMMENDATIONS: It is recommended that the Moyie River water quality monitoring station be deactivated since anthropogenic inputs are limited and water quality is typically good. Due to the break in the long-term dataset, the Moyie River serves as an appropriate surveillance site, but not as an appropriate long-term monitoring site. Also, there are numerous other long-term water quality monitoring stations in the Kootenay watershed and along the Kootenay mainstem that are used to monitor water quality across the Kootenay basin. It is suggested that this site be periodically monitored by B.C. Ministry of Environment staff, and that it be reactivated as a federal-provincial station if anthropogenic impacts become more prevalent in the watershed. |
