CSMI – Stormwater management
“Stormwater management is the planning, design and operation of systems that store, convey, and treat stormwater runoff. By controlling runoff, mitigating flooding and preventing pollutants from entering water bodies, effective stormwater systems can minimize adverse impacts to communities and the natural environment.
With fast-paced population growth, loss of natural areas, and increased development being a common reality for many Alberta communities, concerns related to stormwater management have heightened. With development, more land coverage by impermeable surfaces contributes to increased runoff rates, volumes, and pollutant loadings. These changes can contribute to the degradation of water quality and aquatic ecosystems, urban flooding, erosion and sedimentation, infrastructure deterioration, property damage, and public health risks.” (AUMA, Municipal Water Policy on Stormwater, 2014).
The CSMI region is unique, in that many of the major stormwater drainage corridors are part of the Western Irrigation District works. In some areas, these drainage pathways are natural streams, and in others they are man-made canals. Within the CSMI region, there is farmland located all throughout the WID canal system, and farmers use irrigation district water to irrigate their crops. Managing stormwater from adjacent lands and urban developments is important to ensure water entering the streams and canals has a quality that is adequate for crop application and for protecting the natural stream ecosystems. Appropriately managing storm events also prevents erosion of natural stream banks caused by the significant forces of large volumes of flowing water.
The CSMI is taking steps to ensure appropriate stormwater management is implemented to protect communities and the watershed within the CSMI region.
Stormwater management planning in Alberta
Figure 1. Stormwater management planning in Alberta
Figure 1 shows the current stormwater planning process in Alberta. Planning begins at the highest planning level for the entire river basin, followed by development of a water drainage plan, a master drainage plan, and finally a site implementation plan. This process is required for all developments in Alberta.
The CSMI is unique, as it covers a very specific geographical area and is a regional collaboration of the Western Irrigation District, the City of Calgary, the Town of Strathmore, and Rocky View County. This will allow for ongoing collaboration between the municipalities and the irrigation district for decades to come. This collaboration will also allow the CSMI to manage stormwater under a Master Approval application, instead of individual approvals. This unique process will evaluate and mitigate the cumulative impact of the CSMI System that may be overlooked by separating each stage into individual applications. The assessments carried out to determine feasibility of stormwater management system in the region are aligned with both the water drainage plan and master drainage plan activities.