Have you been wondering about the quality of our lake water?  The results are now in! The Lake Windermere Ambassadors’ volunteers and staff tested the lake from June through September 2012.  The results tell us about the quality of the lake water and how suitable it is for recreation and for fish.

Everyone who was living in the Invermere valley this spring will remember what a rainy June we had.  This rain contributed to a deeper lake. Local residents reported to the Ambassadors that lake levels in 2012 were higher than they’d been in the previous twenty years. On average across all sites on all sampling days, the lake was 0.28 meters deeper in 2012 than 2011. The lake was an average of 0.76 meters deeper in 2012 than the years 2006 to 2008.

A Cool Lake: The lake was relatively cool in the summer of 2012.  Temperature was well within the range of temperatures recommended to keep fish and other aquatic life healthy.

Good for Fish: Dissolved oxygen throughout the lake was at or above the amount needed to protect aquatic life (8 mg/L) during June, July and August.  Lots of oxygen in the water is also good for people since it means that the lake will generally be free of a “rotten egg” smell.

No Excess Nutrients:

Phosphorus, a lake nutrient and also an indicator of pollution, did not exceed recommended values.

Cloudy Water:  Along with the rain this spring came lots of sediment.  Turbidity, a measure of the cloudiness of the water, was high in June and July at north, central and south points of the lake. Compared to historic conditions, turbidity was exceptionally high near Windermere and on the south end of the lake, where it was up to nine times the recommended level.

A channel-scouring event in Windermere Creek brought lots of sediment into the lake and likely increased water cloudiness at the Windermere site.  A landslide in Fairmont Hotsprings in July also brought high amounts of sediment into the south end of the lake. The fact that we saw cloudiness in the water near Timber Ridge during the same time as it was very cloudy near Windermere Creek suggests some influence from the creek persisting in the water as it flowed north through the lake.

Compared to other lakes throughout BC in July, Lake Windermere had the fourth lowest Secchi depth.  The secchi depth gives a reading of water transparency according to the depth of the measurement: the greater the Secchi depth, the clearer the water. Thus, it appears that even given the rainy conditions throughout BC this year, Lake Windermere was especially impacted by inflows of sediment.

A full report is available at www.lakeambassadors.ca.