Risk of Basement Flooding Increased Due to Heavy Rainfall and Increased River Levels
The City of Winnipeg had between 45 and 102 millimetres of rain between 3:00 am and 8:00 am this morning. Some parts of Winnipeg, such as the Westwood area, were showered with 102 millimetres of rain in this five-hour period - more than a month’s worth of rain. Normal rainfall for the month of July is approximately 75 millimetres. The West End of the city, including Charleswood and St. James, experienced a rainfall event that occurs only once in a hundred years. River elevations rose 1.5 feet overnight to 14.8 James Avenue datum.
Dave Wardrop, Wastewater Operations Engineer, reports the following:
All wastewater drainage systems are operational, although at a somewhat reduced capacity due to the high river levels.
17 flood pumping stations are operational and functioned normally throughout the rainstorm.
68 floodgates are active.
Storm water retention ponds are functioning normally to store the heavy rainfall.
There was localized flooding of a few streets in the south area of the city. Most of the water has drained away through catch basins, land drainage sewers and ditches and virtually all streets are reopened.
Crews are investigating flooded basements as a first priority, and second priority is flooded streets.
Wardrop says, “ a number of homes have experienced basement flooding. There are two key factors that determine your risk of basement flooding - where you live in Winnipeg and drainage conditions around your home.”
The risk of sewer backup is greater in homes located in older parts of Winnipeg (generally built prior to 1960). These homes are served by single-line, combined sewers, which carry both sewage and runoff. These sewers can fill to capacity during heavy rains, causing excess water to back up into basements.
Poor land drainage around homes, anywhere in Winnipeg, can further increase the risk of flooded basements. Wardrop says, “The most common problems are soil settling around foundation walls, eaves troughs overflowing near foundation walls, and down spouts emptying too close to foundation walls.” The City recommends residents check around their house during heavy or prolonged rainstorms for surface water collecting against or near basement walls. Areas which are collecting water should be filled in with soil to encourage runoff to drain away from the foundation. Also, residents should clear debris from eaves troughs, and extend down spouts where required. If overflowing eaves troughs are a persistent problem, larger eaves troughs may be required.
To ensure maximum protection against basement flooding, the City recommends installing a sewer-line backup valve and a sump pit with pump in the basement. Professional installation by qualified plumbing contractors is recommended, and a permit and inspection are required.
Wardrop says, “sump pump drainage systems should be inspected every year in the early spring to make sure they are functioning properly for the rainy season.”
For more information on the Basement Flooding Protection Program, residents can call 311. Information about permits and inspections for backup valve and sump pit installations is available by calling 311.