Following a heavy rainfall that took place at the end of June, many Martensville residents were left dealing with the aftermath as the excess water overloaded the drainage system within the City and caused numerous sewer backups.
The drainage structure within Martensville works through a combined system of overland drainage including swales and ditches, and storm sewers. During a rain, the storm water is directed to the city’s network of detention and retention ponds, which are designed to collect and buffer a surplus of storm water during a large rain event. “The pond network is connected by larger ditches which carry water east of the city and drain into the Opimihaw Creek, which eventually discharges to the South Saskatchewan River,” Matt Gruza, City of Martensville Engineer Assistant, explained. “Storm water collection and detention systems are designed using calculations which consider many variables including the contributing drainage area, and the runoff factor of the surrounding land conditions.” For the design, typically a “1 in 100 year” storm event is used to size the storm water system and this is based on historical averages, and years of compiled rainfall data. “This term comes from the fact that in a 100 year period, statistically it would be expected to receive one storm that equals or exceeds the 100-year design storm. Another way of thinking about this is that in any given year, there is a 1 percent chance of getting a storm event that equals or exceeds the 100-year design storm event,” Gruza added.
In situations where the storm sees an intensity and duration that exceeds the 100-year storm event, it is possible that the storm water systems can be overwhelmed and exceed the design capacity; however, if this happens, it doesn’t guarantee that flooding will occur. In cases of heavy rainfall, there are steps that homeowners can take to prevent their home from flooding such as proper landscaping that will help to direct water away from the home foundation, ensuring that sump pump discharge is far enough away from the foundation which will effectively drain water collected by the home’s weeping tile, and the use of backflow preventer valves helps to stop sewage from the sanitary sewer system from entering the home.
Gruza continued to explain that although typically there are not areas of Martensville that see more rainfall than others, “this year, we have experienced some very intense storm cells that are small enough that they only affect certain parts of the city. There is no reliable way to predict how these storms will pass over Martensville.”
If a Martensville resident does experience water or sewage in their basements, Gruza recommends that they cease using water in their homes to prevent further issues. The next step should then be to contact City Hall at (306) 931-2166 and follow the prompts to be connected to the public works emergency line, which is available 24 hours a day. From there City sewer and water crews will assess the situation and determine what the next steps to correcting the problem will be. When there is water or sewage in a basement, it can be caused by a number of scenarios including groundwater, storm water or sewage entering the home in a variety of different ways, and because of this, each individual occurrence needs to be handled on a case-by-case basis. “Even if residents experience minor water issues with their basements, its good practice to report it to the city to ensure that it isn’t the beginning of a more serious problem,” Gruza said.
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