PREPARED BY: Environmental Health
DATE: 2025-02-06
SUBJECT: Beach Water Monitoring Program Enhancements 2025
BACKGROUND/PURPOSE
The Windsor-Essex County Health Unit conducts beach water sampling in accordance with Recreational Water Protocol, 2019 and following the Operational Approaches for Recreational Water Guideline, 2018. The goal of the program is to prevent the incidence of water-borne illnesses and injuries related to recreational water use, and to mitigate risk by preventing the use of public beaches under adverse conditions.
Beaches are monitored to protect swimmers from illnesses that may be linked to high bacteria levels. Swimming in water with high E. coli bacteria levels can result in an increased risk of infection of the ears, eyes, nose and throat or stomach illnesses. To determine the water quality, the WECHU staff collect water samples weekly at eight local beaches (Sandpoint Beach, Lakeshore Lakeview Park West Beach, Point Pelee North West Beach, Seacliff Park Beach, Cedar Island Beach, Cedar Beach, Colchester Beach and Holiday Beach). The samples are then sent to Public Health Ontario Laboratory in London for testing to determine the levels of E.coli bacteria present. It takes at least 24-48 hours for water quality results to be made available online. In Ontario, the recreational water quality guideline is a maximum of 1000 E. coli per 100 mL of water which poses significant health risk to the public. Public beaches must post a closure sign if the beach results show higher than acceptable levels of E. coli bacteria. The posting status for each beach reflects the conditions at the time of the assessment only. Water quality can change from day to day or even hour by hour depending on the weather and other conditions (e.g., bird count, bather load etc.).
To address these limitations, some health units have started utilizing predictive models to enhance their beach monitoring programs. A Predictive Beach Model is a tool that uses current weather conditions, environmental factors such as rainfall, temperature, water turbidity and past beach data to predict future water quality results for public beaches. The predictive model provides community access to timely estimations of what the water quality results may be. These models can be used to supplement weekly beach monitoring and enable prompt public notification due to changing conditions.
DISCUSSION
The WECHU has developed a predictive model that will be ready for implementation during the 2025 beach monitoring season. This predictive model would be an addition to our beach monitoring and notification program to improve public health. The model will utilize historical beach water sampling data from 2014-2023 as well as other potential predictors of E.coli such as windspeed, turbidity, air/water temperature, bird count, wave height and recency/intensity of rainfall. The model will be presented to all municipalities with opportunities to participate at any of the 8 currently tested beaches. The model will use this information along with other predictors noted above to predict what the bacteria levels could be that day. The results for participating beaches will be displayed on the WECHU website daily throughout the season along with the routine weekly beach sampling results.