Lake Erie Hypoxia Forecast

The UWSS will now be posting Lake Erie Hypoxia Reports for 2025 as they become available; these are also received from the (NCCOS). Hypoxia, caused by low oxygen levels in a body water, can be referred to as dead zones, and is inhospitable to many animals.  In the summer the lake stratifies, with warm water on top and cold, dense, deep water below. This part of the lake is typically lower in oxygen levels and has a different chemistry with limited vertical mixing of the cold and warm waters, which further restricts the oxygen levels. The low oxygen water also has different chemistry from oxygenated water, which is problematic for the public water supply. Strong wind events in the summer can cause upwelling, which brings this cold, hypoxic bottom water up to the surface close to shore. This can cause a sudden degradation to the water quality at nearshore drinking water intakes. These events require rapid adjustments to the treatment process in order to maintain drinking water quality. UWSS Inc. continues to monitor these events closely in order to adjust processes quickly in order to continue to provide safe drinking water.  We will be posting regular reports here throughout the 2025 summer season.

NOAA has predicted an extensive hypoxia event in the western basin of Lake Erie for July 11, 2025.  This is due to the rapid increase in water temperature due to the recent heat event our area experienced.  The water temperature of Lake Erie has risen from 26C (79F) to 30C (86F) in some areas.  This increased water temperature is causing some localized hypoxic events.  These events can create some taste and odor issues for our area. 

Residents of the Ruthven Water Treatment Plant should note that operators are working to mitigate the taste and odor issues by adjusting the treatment process.  These adjustments do take time to work their way through the system, approximately 24-48 hours.  The water remains safe to drink, and all testing is within standards.  We will continue to monitor these issues and adjust operations as need be. 

We are hopeful that winds over the weekend will stir Lake Erie mixing the water to alleviate some of the current hypoxia issues.  Updates will be posted as they become available.