Long-range Drainage Master Plan
Following the extreme rainfall events of 1975 and 1983 that caused widespread flooding, a long-range Drainage Master Plan was developed to identify substandard areas and develop drainage upgrade alternatives throughout Regina. In addition, standards for drainage systems have increased over time and applied to new developments. However, it's costly to retroactively apply higher standards to existing development.
New Development Standards
The “minor” drainage system consists of catch basins and underground lines that quickly collect and transport water. The “major” drainage system consists primarily of aboveground facilities such as roadways, easements, swales, and detention and retention facilities that can handle larger volumes of water.
For new developments in our community, minor systems must be designed to handle a 1:5 year rainfall event. This corresponds with the general standard used across North America. While a higher standard would provide a higher level of service, the cost to construct underground facilities to handle larger storms is prohibitive. The major systems must be designed to handle a 1:100 year event.
Existing Development Standards
We have adopted a target of 1:5 year events for existing minor systems and 1:25 year events for existing major systems. Some areas of our community do not meet these targets. In the early 1980s, a program to study drainage problems was initiated to identify solutions and carry out remedial measures to mitigate issues. A Drainage Master Plan designating 17 areas was adopted which was consolidated and updated in 2009. Conditions in each area are assessed, problems identified and potential solutions proposed. Over time, work required to address the problems is carried out through the capital program.
Essentially, this means that our focus is on areas that have the most trouble. Solutions that have the best cost:benefit ratio are determined and being developed over time. Where there is space, the best option is typically a detention pond. The detention pond will also include new or upgraded piping to move water to it from adjacent neighbourhoods and may also include a lift station. Less commonly, we might be able to pipe water to an existing storm channel or to Wascana Creek. An example of this is the current 5th Avenue North Storm Sewer Project. Even more rarely, the only option is an underground storage tank, but that's a very costly option. It is rare for that option to provide sufficient benefit to justify the cost. We do have an underground tank east of downtown, between 11th and 12th avenues and Toronto and Quebec streets.
Recently completed detention ponds in our community include Victoria Avenue and Ring Road (SW corner); Southeast Detention Pond, completed in 2014; Victoria Avenue and Ring Road (SE corner); Parliament Avenue Detention Pond, 2015; and the Arcola Avenue Detention Pond which will be completed in 2018.