The findings are out from a new four-year study, titled Windermere Creek 2009-2012, water quality monitoring report, which took an in-depth look at the health of Windermere Creek.
The waterway was studied using a standardized approach for assessing streams in Canada. Three researchers from Lotic Environmental Ltd. used methods developed by Environment Canada to collect data on bugs, physical features (such as gravel, water depth and velocity) and water quality.
One of the ways this information can be analyzed to understand stream health is to compare the study stream to a group of “reference” sites with similar environmental characteristics. That’s where having information from all across Canada is useful.
“Reference” streams are those that have not been altered by human activity in the stream or its watershed. This information allows researchers to answer the questions: what kinds of bugs should be there? What kinds of physical features should be there? What should the water quality be? If the study stream deviates from reference conditions, it may mean that the study stream is being negatively affected by human activity.
What did we learn about Windermere Creek?
Information was gathered from 2009 to 2012 at sites high in the watershed, below the CertainTeed gypsum mine, and just before the creek enters Lake Windermere. Stream temperatures were within optimal range for westslope cutthroat and bull trout. Water quality at all sites was “good” over the four years of the study, with the exception that turbidity (suspended particles in the water) at the downstream site was above guidelines for the protection of aquatic life in 2011 and 2012. Elevated arsenic levels in the creek sediment were found in 2011 and 2012, but at levels only rarely expected to adversely affect aquatic life.
Aquatic life in the creek
The habitat in the middle site was similar to “reference condition,” meaning it was in good condition.
Based on aquatic bug data, the downstream site was “unstressed” in 2009, but “highly stressed” in 2011 and 2012.
There was a dramatic decline in bug community health in 2011 and 2012 compared to 2010. There were no bugs at all present in the lower part of the stream in 2011. In 2012, the lower part of the stream still had not recovered, as there was a very low abundance of aquatic bugs. The decline in aquatic life was likely caused by a flooding and erosion event in the middle of the watershed in 2011.
The cause of the severely stressed conditions at the downstream site in 2011 and 2012 was attributed to the erosion event. Turbidity levels were also high following the flooding and erosion event. According to the report, “transport and deposition of excessive suspended sediments in streams is detrimental to aquatic organisms including plants, invertebrates, and fish.”
Conditions could improve over time if sediment delivery ceases. More data on bugs, habitat and water quality will be collected in 2013 and 2014. These will be important data to determine whether or not the aquatic health is improving in the lower reaches of Windermere Creek.
Kirsten Harma is the program co-ordinator for the Lake Windermere Ambassadors and can be reached at info@lakeambassadors.ca .