Lake Ontario Flood Watch Update

The Ganaraska Region Conservation Authority advises that over the past week Lake Ontario is rising by 1 to 2 cm per day and its current level is 75.50 m above sea level, which is 52 cm above normal. High water levels are expected to continue for several more weeks while downstream flooding subsides at Montreal and outflows can be increased again to reduce the level of Lake Ontario. The peak water level during the 2017 flood event was 75.88 masl as measured at Cobourg.

 Rice Lake has leveled off at 187.28 m above sea level and may start to decline slightly in the next few days. However, another spring storm is forecast to bring significant precipitation to the region on Thursday. The runoff from this storm may turn around the downward trend in water levels and may temporarily increase levels in Rice Lake by the weekend before they start declining again. Inflows to Rice Lake from the Kawartha Lakes via the Otonabee River have been declining steadily, which continue until summer navigation levels are reached. Outflows from Rice Lake will remain high until water levels decline sufficiently throughout the system. 

High winds and waves are the biggest concern while lake levels are high. With shortened beaches and flooded shorelines, any wave action can cause accelerated erosion rates and could cause damage to shoreline protections and properties that are prone to flooding. Eroding bluffs and flooded shorelines could be dangerous and should be avoided as much as possible over the next several weeks. 

This message applies to the lake shorelines only. The forecasted rainfall will cause an increase in local stream levels and flows later this week, however no flooding is anticipated. 

This Flood Watch for the shorelines of Lake Ontario and Rice Lake within the Ganaraska region will be in effect through Monday, May 13th, 2019. Conservation Authority staff will continue to monitor conditions, and provide updates as necessary. Should you have any questions or wish to report flooding, please contact the following GRCA staff at 905-885-8173.

Note: A Flood Watch is issued as notice that flooding is possible in specific watercourses or municipalities. Municipalities, emergency services and individual landowners in flood-prone areas should prepare.