Why Does Terrell Creek Stink?

We appreciate your concern about the recent state of Terrell Creek. The sight and smell of the water may seem like cause for concern; however, the conditions you’ve noticed are actually a natural seasonal occurrence caused by lack of rain in the late summer/early fall. Bacterial and algal growth occur when water levels are low, slow moving, warm and nutrient-rich. There is also a buildup of decaying organic matter like seaweed in Birch Bay and lower Terrell Creek every summer. These natural conditions generate strong sulfur smells, surface films, and unusual colors in the creek. The extent and severity of the smell and murkiness varies annually, and this year has been particularly noticeable. The issues will resolve and the creek will return to its normal look and smell once the fall rains start flushing out the waterways. 


We have been responding to citizen reports of unusual sheens, smells, and colors in Terrell Creek over the past few months. Staff have not found any conditions to date that are cause for concern; however, it’s still a good idea to keep kids and pets out of the water until it’s no longer stagnant and stinky.


The conditions described above do not need to be reported; however, there are a few observations that are important to report:



Here are some additional resources and tips:

  • Organic matter like bacteria can create a natural sheen or surface film that looks like an oil sheen. A simple way to tell the difference is to throw a rock or poke a stick into the film. Natural sheens break up into small fragments. Petroleum sheens will quickly reform and are more likely to have a rainbow color.
  • Sulfur-loving bacteria thrive in the summer. These bacteria may be pink or white and smell like sulfur. Decaying seaweed and aquatic vegetation also add to the stink. Learn more about the causes of beach odors at these links:
  • Who is monitoring the water quality?
    • Whatcom County Public Works staff sample the creek and other locations in the watershed twice a month to monitor fecal coliform bacteria levels. The results are posted on this map and on this website at least monthly. 
    • Whatcom County Health & Community Services staff monitor water quality for swimming in Birch Bay between Memorial Day and Labor Day as part of their BEACH program. 
    • Whatcom County Health & Community Services staff regularly monitor for marine biotoxins (poisons produced by certain kinds of microscopic algae) and close shellfish harvesting areas when unsafe levels are detected. Check the Shellfish Safety Map for beach closures and advisories on the day you plan to harvest shellfish.