| Abstract/Description or Keywords |
The 2010 KSM Project Water Quality and Aquatic Resource baseline program was designed to continue work started in 2007 by collecting baseline water quality data for streams and rivers within the Project study area. To meet the program objectives, 30 stream sites were selected within the KSM study area (i.e., Mitchell/Sulphurets/Unuk, Teigen/Snowbank/Bell-Irving and Treaty/Bell-Irving watersheds). At each site, water quality samples were collected to characterize the natural spatial and temporal variation present in these systems. Water samples were collected on a monthly and quarterly basis and water quality parameter concentrations were compared to federal and provincial water quality guidelines. The aquatic resource program added a new site in Gingras Creek in August, a south flowing tributary that joins Sulphurets Creek immediately downstream of the mouth of Mtichell Creek. This site was sampled for sediment quality, periphyton, and benthic invertebrates. Overall, most streams in the KSM Project area in 2010 were slightly basic, with low to moderate buffering capacity and soft to moderately hard water. pH values were slightly basic at most sites and were within the CCME water quality guidelines for the protection of aquatic life. Alkalinity at most sites was moderate and was lowest during the summer months due to the dilution from freshet and glacial melt waters. The exception was three sites within the Mitchell Creek watershed, MC1A, MC1A-US, and MC1 located just below the toe of the Mitchell Glacier. pH at these sites was acidic (ranging from 2.9 to 4.7), and was below the lower CCME and BC Maximum guidelines limit (pH=6.5). Alkalinity at these sites was also low. General physical parameters of water, such as hardness, total dissolved solids and conductivity were lowest during freshet in the spring and early summer and during the heavy rains in the fall. Total suspended solid concentrations, turbidity and metal concentrations, were generally highest during high flow periods. Concentrations of many metals naturally exceeded the provincial and federal water quality guidelines for the protection of aquatic life, reflecting the naturally high mineral content of the KSM Project waters. Parameters that exceeded provincial and federal water quality guidelines were fluoride, sulphate and a group of metals that included total aluminum, arsenic, cadmium, chromium, copper, iron, lead, manganese, selenium, silver, zinc, and dissolved aluminum and dissolved iron. The frequency of exceedances was highest in the Mitchell and Sulphurets watersheds. The lowest concentrations of metals were found within the Teigen Creek watershed. At the three low-pH sites within the Mitchell Creek watershed (MC1A, MC1A-US, and MC1), metal concentrations were higher during the low flow period. These sites were most likely influenced by groundwater seepage and naturally occurring acid rock drainage. The sediments at the Gingras Creek sampling site were largely composed of sand (89%). Concentrations of total nitrogen and available phosphate were low, while arsenic, chromium, copper, and nickel all exceeded the CCME and BC sediment quality guidelines. The average density of periphyton was 6.6_106 cells/cm2 and the periphyton community was dominated by a single species of blue-green algae, Homoeothrix varians. The average periphyton biomass was 0.13 Gg chl a/cm2, with an average richness of 19 taxa, and Simpson’s Diversity Index of 0.024. Benthic invertebrate communities had an average density of 163 organisms/m2 and consisted of 15 taxa. Benthos was dominated by insects, particularly Plecoptera (64%), followed by Chironomidae (20%). |
