Low water advisory issued for St. Clair region
Ongoing dry conditions have prompted the St. Clair Region Low Water Response Team to declare a Level 2 Low Water Advisory for two subwatersheds in the St. Clair Region.
Low water conditions are evaluated by looking at several indicators, including precipitation over the past three months and stream flows over the past month. “During the last three months most of the St. Clair Region watershed has had only about 60% of normal precipitation and the current month has been particularly dry,” Girish Sankar, Water Resources Engineer for the St. Clair Region Conservation Authority said. “April showers were only about a third of the normal 80 mm. In addition, the light snow pack during the winter resulted in a smaller spring melt. As a result, many rivers and streams are already at mid-summer levels,” Sankar explained.
While all areas are suffering from low water levels, upstream areas and areas with little groundwater recharge are hardest hit. A Level 2 advisory was issued for the middle and upper East Sydenham River watershed upstream of Dresden and Strathroy respectively. The remainder of the region has been declared to be under a Level 1 Low Water Advisory.
The Level 2 Low Water Condition is part of a three-tiered advisory system used in Ontario to inform the public of local low water conditions with Level 1 being the least severe and Level 3 being the most severe.
Low water has an impact on water quality and on the wildlife that live in the river. “Even though the river looks more clear than usual, because sediments aren’t being stirred up by rain, the nutrients carried by the river become more concentrated when water levels are low,” Muriel Andreae, Senior Biologist for the SCRCA said. “With low water levels and no cooling rains, the watercourse becomes warm much earlier than normal and may cause challenges for fish and the insects they eat,” Andreae said.
The low water levels also expose a wider shoreline and shallow bars and this may even strand mussels. “The mussels of the Sydenham are nationally significant and include many species that are at risk for Ontario and Canada,” Andreae said. “High nutrient levels were already a concern for these mussels. This summer, low flows may exacerbate the problem.”
There is concern that these dry conditions may continue and worsen in the summer months, when water demands are higher. While all residents in the St. Clair region watershed are encouraged to use water wisely, residents utilizing water from the East Sydenham River are being asked to voluntarily reduce water use by 20 per cent as a result of unusually low water levels.
The Low Water Response Team is made up of representatives from watershed municipalities, government agencies, agriculture, aggregate industry, golf courses and the St. Clair Region Conservation Authority.