• Lower Thames watershed has already received 15 to 35 mm of rain in the last 24 hours with an additional 15 to 25 mm still in the forecasts for the next 24 to 36 hours. Potential thunderstorms could drop more rain in some areas.
• Local watercourses have risen rapidly and some have already reached bank full conditions or spilled their banks. With additional rain in the forecast, further rises in water level are expected.
• LTVCA planning to operate the McGregor Creek Diversion Channel this evening.
• High lake levels could aggravate drainage issues in shoreline areas.
• Thames River should be expected to rise up enough to flood the sidewalk in downtown Chatham.
Over the past 24 hours the lower Thames watershed has received between 15 and 35 mm of rain, with the heaviest rainfall amounts falling in eastern Chatham-Kent and the southwest of Middlesex and Elgin Counties. The upper Thames watershed has received substantially less rain than the lower Thames. There is still significant rainfall in the forecast for the lower Thames watershed with 15 to 25 mm of additional rain still possible over the next 24 to 36 hours.
Local watercourses have risen rapidly in response to the heavy rains. Some watercourses have already reached bank full conditions or spilled their banks into adjacent low-lying floodplain areas. With the additional rain in the forecast, local watercourses should be expected to rise even further. McGregor Creek is still rising rapidly and the LTVCA is planning to operate the McGregor Creek Diversion Channel late this afternoon or early this evening when its operating thresholds are expected to be reached. Also, with the amount of rain still in the forecast additional ponding and localized flooding issues should be expected in areas with poor drainage.
The rain in the forecast could have a greater impact in shoreline areas. Due to the high lake levels, rainwater is not draining properly from these areas. In addition, any water from upstream making its way downstream on local watercourses into these shoreline areas could further impact these areas.
The high water levels on Lake St. Clair are having an impact on water levels in the Thames River all the way up into the city of Chatham. Water levels on the river should be expected to rise and flood the sidewalk along the river in downtown Chatham. Very low lying floodplain areas adjacent to the river could also see some flooding. As the upper Thames watershed did not receive as much rain as the lower Thames, significant flooding on the river beyond this is not expected.
In order to reduce nuisance flooding, residents should ensure that catch basins and other drainage areas are clear of debris.
People should take extra caution and avoid the river, ditches, and streams. The combination of slippery banks and fast moving cold water can be dangerous. Standing water can also present unseen hazards. Children and animals should be kept away from the water.
Officials will continue to monitor the situation and update this advisory if necessary.
This message will be in effect until March 30, 2020.
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