This Tuesday’s test results revealed a temporary, but significant spike in levels of E. coli in the North Saskatchewan River. The reason for the increased level of bacteria is not clear and tests will continue well into September along with the swimming season. Bacteria levels decreased on Wednesday, but given that water quality changes from day to day, it is not possible to predict E. coli levels ahead of the weekend when crowds will return to Cloverdale Beach and other recreation hotspots along the North Saskatchewan River.
The North Saskatchewan Riverkeeper’s recreational water monitoring program conducts tests along the river at key access points within the city of Edmonton and this week’s results are now available in Swim Guide. The program tests for E. coli, which is the standard bacterial indicator for recreational water quality as established by Health Canada guidelines. A beach is posted red when levels exceed 200 CFU/100ml (colony forming units of E. coli per 100 ml of water) and green when levels are equal to or below 200 CFU/100ml. Please note that results only reflect water quality at the time of sampling and that E. coli levels are only one of many factors that affect the overall risk level of recreation activities in moving water.
Water Quality Update: Sampled Tuesday, September 5th, 2017
Test Result: 359 CFU/100ml
Test Result: 422 CFU/100ml
Test Result: 746 CFU/100ml
Conditions on day of sampling: Sunny and clear
The Fort Edmonton Footbridge Sandbar was not tested this week. Click here for last week’s results.
Read our earlier blog post outlining the details of the monitoring program and to learn more about how to determine the safety of recreation in the river. The results posted here only reflect the water quality at the time of sampling and are only one of many factors that affect the risks associated with recreation in a moving body of water.
The Bigger Picture
Water quality in the North Saskatchewan River fluctuates from day to day and depending on the location and conditions, it is not uncommon that recreational water quality standards are exceeded. Test results only reflect water quality at the time of sampling, and because water quality often changes quickly in moving water, it is difficult to predict E. coli levels on the days that follow or even later on the same day. For this reason, it is important to interpret individual test results within the context of water quality trends over time. A full report outlining the findings of the monitoring program will be published later this fall.
Between August 1st and September 8th, North Saskatchewan Riverkeeper published 18 test results at four locations including three for the popular Cloverdale Beach. Nine out of 18 results met the Health Canada standard for recreational water quality of 200 colony forming units of E. coli per 100ml of water (CFU/100ml). The other nine results exceeded the standard.
At Cloverdale Beach, test results to date are as follows:
123 CFU/100ml (Met water quality standards)
238 CFU/100ml (Failed to meet water quality standards)
746 CFU/100ml (Failed to meet water quality standards)
Additional E. coli data based on daily samples taken from the Rossdale Water Treatment Plant intake show that E. coli levels just upstream of Cloverdale Beach were recorded at 460 CFU/100ml on September 5. This was the highest result in that period of time – between September 1 and September 6 the average (geometric mean) level of E. coli at the intake was 142 CFU/100ml, which is within federal guidelines.
In the preceding period for which data is available (August 24 – August 30), the results exceeded federal guidelines, with a geometric mean of 254 CFU/100ml. Water quality is generally better at the intake than at any location downstream of the plant and the numbers confirm that depending on the day, Cloverdale Beach may or may not be suitable for swimming.
Health Canada guidelines are designed to limit the contraction of waterborne illnesses to 1-2%, or 10-20 illnesses for every 1,000 swimmers. When a beach fails to meet these guidelines, the risk of waterborne illness increases.
Download the press release.