Posted By: Thea Rodgers

Our first excursion to sample the lake water this year was April 24th.  It was a blustery day, with very low water levels.  Too low to launch the motorboat, we embarked in a flatwater kayak to face the waves and collect Phosphorous samples!

The lab results came back showing very low Total and Dissolved Phosphorous concentrations, much lower than the values we recorded in 2014 and 2015 which exceeded Ministry of Environment recommendations.  A good sign for our naturally nutrient-poor (“oligotrophic”) river system!

Together, Thea and Rachel began our weekly summer sampling sessions just earlier this week, on May 29th. Can you believe that the lake water was reading at over 19 degrees Celsius in the northern parts of the lake?! It was so warm, even at depth, that we wanted to jump in for a swim.

The lake is also much higher now, having gone up about 3-4 feet (1-1.2m) since late April.  We are in the middle of the spring melt and runoff, which makes the warm water temperatures quite odd. We normally expect to see a drop in water temperature around this time because of the influence of snowmelt on tributary inflows to the lake.  The following day, we traveled to Windermere to test the quality of Windermere Creek. The temperature of the creek water is only 8 degrees Celsius. A stark difference from the refreshingly warm lake water!

What causes this temperature difference between lake and creek? Well for one, Lake Windermere has a much larger surface area than Windermere Creek, and it isn’t shaded by riparian trees and vegetation like the creek is. This means the lake has more water surface area which can be warmed by the sun – and it has been very hot and sunny over the past couple of weeks! Air temperatures even reaching up to 30 degrees in the shade. These are unusual temperatures for May in the Columbia Valley, and it appears to be reflected in the lake water as well.

Turbidity is much lower than in early June of 2017. Last year, we had a turbidity reading of 24 NTU and the water was very cloudy and murky. On Tuesday, we collected a sample with a turbidity of 9.5 NTU, so not nearly as high as in early June of last year. We will continue to sample every week through early June, and hope to observe a noticeable peak and decline in turbidity which is characteristic of the spring freshet!

The last notable result is the lake level: at approximately 7.3 m deep, this is the highest recorded depth we’ve observed since 2013. It’s showing around town, too, as many shoreline areas and boat launches are close to flooding.

The wetlands are also full up with the melt water. Wetlands are vitally important to our urban communities, because they help store floodwaters and can even help recharge groundwater storage. In doing so, wetlands protect our urban areas from flooding damage and help ensure smooth completion of the entire water cycle.

We are very lucky to have some of the world’s most beautiful wetlands just outside of our back door (the Columbia Wetlands & Wildlife Management Area), and it’s amazing to see them recharge with water at this time of year! This annual flooding helps maintain wetland soils and native vegetation, which supports the important insects, microbes, wildlife, fish and migratory bird species that rely on healthy wetland ecosystems for survival!

If you’d like to learn more about watershed ecology and the role we can play in protecting our local watershed, please contact us at info@lakeambassadors.ca, or give us a call at 250-341-6898. If you want to sign up to join us on the water for a lake sampling day as a citizen scientist, please contact Rachel at intern@lakeambassadors.ca!