GRCA Issues Updated Flood Warning – Lake Shorelines

Flood Potential: High

The Ganaraska Region Conservation Authority advises that very high water levels on Lake Ontario are expected to persist through May with potential for shoreline erosion and flooding. Also, water levels on Rice Lake are rising due to the runoff associated with last week’s three day rain storm and are currently 45cm above summer levels.

The water level on Rice Lake is expected to continue rising for the next few days as the large volume of runoff makes its way toward Lake Ontario. Any rainfall at this point is likely to cause more runoff and may increase water levels or slow the rate of decline once the level has crested.

Lake Ontario water levels have reached critical levels (75cm above normal) causing shoreline flooding and wind driven erosion. Heavy rainfall in April and May has caused the increase in water levels, while severe flooding in the St. Lawrence and Ottawa Rivers has prevented a greater release of water from Lake Ontario.

High Lake Ontario levels are also causing flooding in stream outlets (estuaries) in Cobourg, Port Hope and Newcastle as well as beach inundation and erosion. If winds from the south pick up while the water levels are high, there will likely be more active erosion and potential flooding as waves rush up on our shorelines.

The public and especially children are reminded to be aware of shoreline hazards that are not normally present. Saturated and eroded shorelines may be unstable and should be avoided particularly during high winds and waves.

This Flood Warning for the Lake Ontario and Rice Lake shorelines will be in effect through Sunday, May 31st, 2017. 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.

Mike Smith
Flood Operations Officer

Mark Peacock, P.Eng.
Flood Forecasting and Warning Coordinator

Note: A Flood Warning is issued as notice that flooding is imminent or already occurring in specific watercourses or municipalities.