| Abstract/Description or Keywords |
When comparing the benthic invertebrate community results at test sites to reference sites, all sites were unstressed to potentially stressed except for two sites, which were both on the Slocan River. One of these two sites was just south of Slocan (NJSLO02) and went from potentially stressed to severely stressed the last time it was monitored in 2009 and the other site in Crescent Valley (NJSLO01) was stressed every second year that it was monitored. For water quality analysis, several sites had guideline exceedances. NJSLO01 had pH exceedance for portions of 2011 to 2013 and total phosphorus exceedance once in 2009. Wilson Creek (NJWIL01) had pH exceedance in 2010. For NJSLO01 there were exceedances in the water of cadmium and zinc in 2008 and the Winlaw portion of the Slocan River (NJSLO03) had these metal exceedances in 2007. The sediments of NJSLO01 were found to have exceedances of cadmium and zinc in 2010. Bonanza Creek (NJBON01) had sediment exceedances in 2012 of cadmium, iron, manganese, nickel, and zinc. A range of thermal conditions was observed at the various sites. Three of these sites were along the Slocan River where the maximum temperature was approximately 23 °C and at the fourth site along Winlaw Creek the maximum temperature was much lower at about 14 °C. The stressed invertebrate community rating at NJSLO01 was determined by the CABIN model. The model that determines the overall conditions is complex, and compares multiple metrics between the test and reference sites. Overall the differences between stressed and potentially stressed years at this site were marginal when the vector graphs were reviewed, indicating that the stressed sites were not dramatically different than the potentially stressed sites from year to year. The stressed conditions also did not appear to be the result of water quality exceedances, as the exceedances did not occur during the years identified to be stressed. The exceedances were also marginally higher/lower than the guidelines. Because of this, there was not a high level of concern with the results for this site. Similarly, the low effect sediment guideline exceedances at NJBON01 were not evidenced to impact the benthic community assemblages. Water quality was not collected at NJSL002 to allow for a review of the cause for the severely stressed rating in 2009. However, this was a year in which the maximum and average yearly stream temperatures were cooler. |
