WWU monitors say Lake Whatcom water quality showing signs of improvement
Lake Whatcom has been on the state’s list of polluted water bodies for 25 years, and it is the primary source of drinking water for most of Whatcom County. Thanks to recent restrictions, the quality of the lake’s water appears to be improving.
Lake Whatcom has been on the state’s list of polluted water bodies since 1998, as a result of the poor dissolved oxygen levels in the water. This result is a direct cause of human action in Whatcom.
“When humans make changes, anything that disturbs the watershed, those activities have the potential to release sediment. That can run off into the lake,” Angela Strecker, director of the Western Washington University Institute for Watershed Studies, told The Bellingham Herald. “That sediment often contains pretty high levels of phosphorus,” “There are potential other sources ... but human conversion of land is one of the main sources. ... The lake sits at the lowest point of the watershed, so anything that happens in that watershed is going to get funneled down to the lake. The lake takes the brunt of all the things that we do, all the actions that we take within the watershed.”
The institute has been monitoring the water quality of Lake Whatcom with funding from the city of Bellingham.
Human actions, such as development in the Lake Whatcom Watershed, has been adding more phosphorus and nitrogen to the lake. Development of the surrounding area, such as lawns and roads, mean chemical elements such as phosphorus and nitrogen are not naturally filtered out of stormwater and washes directly into the lake, according to the Washington State Department of Natural Resources.
“Computer predictions show the lake would meet state standards for dissolved oxygen if there was 86 percent less development than existed in 2003. Since then, zoning laws have allowed more development in the watershed,” according to the Washington State Department of Ecology.
Algae feeds on phosphorus and nitrogen, so the more of these elements, the more algae. Algae is useful in moderation, but it can be harmful if it blooms out of control. These blooms die quickly, and decompose at the bottom of the lake. The bacteria responsible for the decomposition use a lot of oxygen, thereby lowering the overall oxygen level in the lake, Strecker said.
Restrictions were put into place to reduce the amount of phosphorus and nitrogen that was draining into the lake around 2016. These included restrictions on excavations and soil removal, limits on phosphorus based fertilizer and the introduction of multiple stormwater treatment facilities. Gary Stoyka, natural resources program manager for the public works department, said they also increased public awareness of the problems, and increased the maintenance on street cleaning systems, as a large amount of phosphorus runoff was found to be a result of street sweeping.
It will be a long time, about 50 years, before there is any major and noticeable change in the water quality, Stoyka said. However, there has been some minor changes over the last 10 years to suggest these restrictions have been effective.
It seems the restrictions may be working.
The Institute of Watershed Studies has noticed phosphorus levels in some parts of the lake have stopped increasing, and are starting to come back down. This is only the case in a portion of the lake, and it is still too early to tell if this is a continued trend, or an outlier, but it gives hope to the idea that the restrictions are working.
This story was originally published December 16, 2023 at 5:00 AM.
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