| Abstract/Description or Keywords |
The health of Windermere Creek was reviewed using the results of benthic invertebrate and water quality monitoring from 2009 to 2012. Monitoring was conducted at four sites on the mainstem, representative of the upstream section of the creek, the mid-stream section, and the furthest downstream section. o Overall, the monitoring results showed variability in the health of the Windermere Creek. Indications of stress were apparent throughout the creek at various times. The most apparent water quality impact with the potential to impair benthic community health was elevated turbidity. Monitoring results showed how stream health can recover under improved conditions. o The upstream site (NAWIN01) was stressed in 2010 but only potentially stressed in following years. The stressed condition was indicated by several macroinvertebrate community indices. The stressed macroinvertebrate condition was attributed to habitat impacts which caused reduced depth and velocity, and increased embeddedness of dominant substrate with fine substrate. The cause of these conditions is unknown. o The initial mid creek study site (NAWIN02) was only monitored in 2009 and 2010, since it was buried by an erosion event in 2011. The event is an example of ongoing erosion concerns in the watershed. Prior to this event, the site was unstressed with no water quality concerns. Its replacement (NAWIN04) provided another example of conditions improving with time. NAWIN04 was potentially stressed in 2011, and was similar to reference condition in 2012. Water quality remained consistent through this period. o The downstream site (NAWIN03) located near the Windermere Creek outlet to Windermere Lake was found to be in good condition (potentially stressed) in 2010. The site showed a dramatic decline in benthic community health in 2011 and 2012 as a result of extreme sediment loading. The decline was evident as no to very low abundance of invertebrates. Water quality sampling at NAWIN03; however, revealed that there have been elevated turbidity values periodically since 2011. Transport and deposition of excessive suspended sediments in streams is detrimental to aquatic organisms including plants, invertebrates, and fish. Additionally, elevated turbidity in streams is a concern for raw drinking water. Erosion sources have been identified with evidence that they will persist into the future (McCleary 2012). Thus, options to stabilize the channel should be sought. o Sediment quality (only monitored at NAWIN03) revealed elevated arsenic concentrations relative to guidelines in 2011 and 2012. The likelihood of effects on the biological community was uncertain at the concentrations measured. This is because arsenic exceeded the low effect guideline, above which adverse biological effects are expected to only rarely occur (CCME 2001). The probable effect level guideline, above which adverse biological effects are expected, was not exceeded. o Stream temperature at NAWIN01 was generally lower than NAWIN03 and monthly average stream temperature values were within the optimal range for westslope cutthroat trout and bull trout rearing. |
