Since 2007, WLI has sampled the lake monthly taking both water samples and water sensor data at two points in the lake. One sample point is near the south end of the lake and another is at the deepest part near the north end of the lake. Below are summary graphs using yearly average data from both sampling locations in June, July, and August. Each graph shows yearly average and error bars representing standard error of the yearly average. Overall, due to efforts from the community of Whitefish and WLI the lake remains relatively low in nutrients and high in water clarity. The lake shows no indication of long-term negative trends in water quality. This is a huge testament to the community of Whitefish's commitment to protect and maintain its water resources.
Water Clarity (Secchi)
Water clarity is an important variable for both water health and aesthetic and economic value of Whitefish Lake. Secchi is measured by lowering a black and white disk into the water until it disappears, that depth is then marked as the Secchi depth. Thus, the best water clarity creates the deepest Secchi depths. Whitefish Lake has maintained consistent high water clarity and does not have a strong trend of decreasing water clarity. The long-term average Secchi depth is 23 ft.
Surface Temperature
There is a slight increasing trend in Whitefish Lake surface temperature. The long-term average surface temperature is 62 degrees. Higher lake surface temperatures can lead to more algal production.
Total Nitrogen
Nitrogen is a nutrient used in algal production and high levels of nitrogen can often result in algal blooms. Increases in nutrients such as nitrogen are often due to human influence. Whitefish lake has no trend in total nitrogen, recent years have been below the long-term average of 79.05 ug/L. Overall, Whitefish lake has low nitrogen levels.
Total Phosphorus
Phosphorus is a nutrient used in algal production and can often come from human driven sources such as septic leachate, fertilizer, or detergents. Whitefish lake has no trend in total phosphorus, although some monthly values have been above the long-term summer average. The long-term average for phosphorus in Whitefish lake is 3.59 ug/L which is considered low.
Chlorophyll
Chlorophyll is a pigment within algae, and it is used as a proxy to measure lake algae production. Whitefish lake has a small increasing trend in chlorophyll indicating that the mid-lake algae levels have slightly increased throughout the last decade. Near shore algae may not be reflected by this trend though as the long-term sampling locations are in well mixed deep regions of the lake. The long-term average for chlorophyll in whitefish lake is 1.45 ug/L which is low indicative of whitefish lake’s low nutrient levels.
Deep Lake Temperature
This represents the lake temperature in the bottom 5 meters of the lake. This is the coldest area of the lake and important fish habitat. Whitefish lake has a slight increasing trend in bottom of the lake temperature which could indicate that over time without improvement this important fish habitat may be at risk of being lost due to an increased temperature.
Deep DO
Dissolved oxygen at the bottom of the lake is important for fish habitat. In many lakes due to longer and warmer summers in deep waters, dissolved oxygen is decreasing. In Whitefish Lake dissolved oxygen levels are remaining high. The summer average of dissolved oxygen saturation is 84%
