The Lake Simcoe Region Conservation Authority is warning that heavy rain in the forecast could lead to flooding in some areas of the Lake Simcoe watershed starting Monday.
The conservation authority says Environment Canada has a special weather statement in effect for the area.
Significant rainfall is forecast for Monday in portions of the Lake Simcoe watershed, with predicted rainfall accumulations of 30 to 50 millimetres.
Higher amounts of rainfall may occur in localized areas, the conservation authority warns.
It says while widespread flooding is not expected, the expected rainfall may result in flooding of low-lying areas.
According to the conservation authority, rainfall will cause all watercourses in the area to experience higher than normal water levels and flows, leading to local streams and rivers becoming dangerous, especially in the vicinity of culverts and bridges.
Children should be warned to stay away from all watercourses.
Higher than normal water levels are expected to last until at least Wednesday.