Sewer Relief Project

City of Selkirk

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Basement Flooding has been a major problem for city of Selkirk residents.

High intensity summer rain storms can result in extensive basement flooding as the high

rate and volume of runoff exceeds the capacity of the existing sewer system.

This is particularly the case in areas served solely by combined sewers.

In 1992 Selkirk retained an engineering firm to carry out hydraulic analysis of the existing combined and land drainage sewer systems.

This study featured the development and calibration of a computer model (SWMM) of the sewer systems to access the existing level of basement flood protection and the conceptual design of relief measures to upgrade the sewer system to the Council selection 10 year level of protection.

Sewer Relief Study

The City of Selkirk, Sewer Relief Study was completed in 1993 and recommended selective storm water separation from the combined sewers to new (or existing) land drainage sewers to achieve the minimum level of basement flood protection.

The first phase of the recommended plan was constructed in 1995/96

These major works included a new outfall on Christie Avenue and the separation of the highly impervious downtown area to new land drainage sewers, along with some cost effective separation of areas adjacent to existing land drainage sewers.

The recommended basement flood relief plan provides a ten-year level of basement flood protection by removing storm water inflow to the combined sewer system and redirecting the flow to new land drainage sewers.

Sewer Relief Construction Staging Map

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This map shows the staging of the storm water separation work in Selkirk.

The two sections identified as #1 on this map were completed in 1995.

These areas constituted the worst areas in Selkirk for basement flooding during major storm events.

Sewer Relief Construction Staging Map

In 2000, the area identified as area #14 was completed.

This area was completed entirely as surface drainage or ditching.

This work was done by in-house staff at a very nominal cost.

The ability to use City staff was one of the reasons why area #14 was the next section done, but also because this portion of drainage also assists in draining the storm water from surrounding areas.

Originally it was thought that areas #2 and #3 would be the next sections that would address storm water separation from the sanitary system, but in closer review, section #4 had more homes that experienced basement flooding during heavy rain events than section #3.

The Operations Department re-prioritized the order of work and proposed #2 and #4 to give Selkirk the greatest results for separation of storm water.

Through direction from Council and funding assistance from the Province and Federal Government, the City addressed the most challenging sections of Selkirk.

At this point, the City of Selkirk has addressed approximately 40% of the proposed sewer relief work.

The next section to be addressed is area #3

All of the preparation and engineering work has been completed and is considered “shovel ready” which means if and when the funding becomes available to do this work, the Operations Department could have a tender package prepared quickly and begin the work almost immediately.

The proposed section #3 work is estimated at $1,656,000

What’s Next

Once area #3 is completed, we move down the map to area #5

This appears as a relatively small, odd shaped section on this map, but it is important to address this section next because #5 is designed as a main trunk to carry storm water from the surrounding sections of land

So as you can see, each section on this map has been plotted out in a specific order so that the City of Selkirk can gain the greatest benefit in the first sections.

By phasing the work as shown, it allows the project to be more affordable and achievable.

Conclusion