Heavy rains forecast for Monday into Tuesday could cause rapid increases in water levels in small streams and raise rivers and lakes to above normal levels.

The Meteorological Service of Canada (MSC) has issued a Rainfall Warning that says “A slow moving upper disturbance over Lake Huron is expected to generate significant rainfall amounts over much of Eastern Ontario”. As much as 100 millimetres (mm) of rain is possible over a wide area.

A few days without rain provided some capacity for infiltration of the rain into the soil but that storage has been filled with water levels already on the rise from rainfall this morning. Levels will continue to increase throughout the day.

Flows in smaller streams could go over their banks with heavy localized rain in thunder storms. The rivers in the watershed are not expected to go to the onset of flooding but higher waters may affect navigation on lakes and rivers if normally visible hazards are submerged. Anyone boating on area lakes and rivers needs to be cautious and parents need to remind children of the risks of high levels in all waterbodies.

For water level and flow information in the Rideau system as well as the Ottawa River, visit the RVCA Streamflows and Water Levels webpage at http://his.rvca.ca/rvcafwl/ .

For more information about conditions on the Ottawa River, check the webpage of the Ottawa River Regulation Planning Board at http://ottawariver.ca/river-levels-flows.php#river-levels-flows-7-days.