--- Water quality returns to normal after high temperatures and significant rainfall led to beach closure at Des Cèdres in August
Water quality at Des Cèdres Park beach has received a good grade from the City of Gatineau in its most recent tested samples from August 26. The beach has experienced higher levels of e-coli this summer, which forced the city to close the beach from August 6 to August 19.
Water quality for recreational water use is tested at all the city’s beaches throughout the summer season from June to September. Samples are collected twice weekly when possible, on Monday and Wednesday mornings, and are evaluated on a sliding scale from A (‘Excellent’) to D (‘Polluted’). The City of Gatineau issues a no swimming advisory when five test samples average above 200 units of e-coli per 100 millimetres.
Ottawa Riverkeeper, a non-profit that monitors the health of the Ottawa River system, also does its own sample testing for e-coli levels at Des Cèdres beach. Katy Alambo, a biologist from the organization, says there are a lot of things that contribute to water quality at urban beaches. For instance, large amounts of rainfall can increase levels of e-coli in water because it often washes a lot of the bacteria throughout the city and the environment into the river system. “In early August, we did have quite significant rainfall events for a number of days and this was also coupled with very high temperatures,” she said. “These high temperatures can also help contribute to higher e-coli levels because it needs warmer temperatures to grow and proliferate.”
Ottawa Riverkeeper recommends that people not swim within 24 hours after significant rainfall, because the water will most likely have increased e-coli levels. The beach showed a higher water quality fail rate of 36 per cent this year, compared to 2019 when it failed only 5 per cent of its tests. When asked whether the COVID-19 pandemic and increased use of the beach contributed to this higher fail rate, Alambo says the data needs more explanation before making that determination. “We tested there [Des Cèdres Park beach] 30 times over the course of this summer to date, and the City of Gatineau increased their water testing frequency as well, so we just have more data points, which can play into that,” she said. “In the past, when we were testing less often, it’s possible we missed days when the beach might have failed.”
Water quality can differ from one day to the next in rivers, because water can move quickly downstream and replace existing bad water. This is why Alambo says frequent testing remains important.