PUBLISHED: 25 June 2018      Last Edited: 29 May 2023

About the Stormwater Management Cooperative (CSMI)

Why is the CSMI needed?

There is a large tract of land spanning the Eastern edge of the City of Calgary, the Town of Strathmore, and Rocky View County where there are limited natural drainage courses to effectively transfer stormwater. Ongoing development in these communities, which are adjacent to and surrounding the Western Irrigation District (WID) irrigation system, has been accelerating stormwater management challenges in the area. This includes creating ongoing maintenance and water quality challenges for the WID and limiting the available options for new developers to safely move runoff away from their properties. 

There is a need to develop a long term, sustainable solution for stormwater management that facilitates municipalities to grow and develop land, while maintaining water quality in the irrigation system that supports a vibrant agricultural economy and the long-term health of nearby water resources. 
In 2012, the Western Irrigation District responded to this need and spearheaded an effort to bring together three partner municipalities to develop a regional stormwater solution, now known as the Stormwater Management Co-operative (CSMI).  

Stormwater is water that flows over land during rainfall and snowmelt events, also called runoff. Stormwater management systems may store, move, and treat stormwater runoff to minimize negative effects to communities and the natural environment. Development decreases the natural landscape’s ability to absorb some of the runoff and remove pollutants before it drains off the landscapes, often increasing the need for stormwater management systems in developed areas. This increases the risk of flooding while water quality of downstream water bodies deteriorates as the water eventually drains to surface or groundwater outlets.1 Municipalities therefore require development to achieve pre-development conditions of stormwater quantity as well as meeting certain water quality parameters. 

1. Environmental Service, Government of Alberta (1999). Stormwater Management Guidelines for the Province of Alberta.  

Who is involved?

Recognizing a shared responsibility for the system’s current challenges, the municipalities surrounding the WID have come together as the CSMI to proactively collaborate in developing sustainable stormwater solutions that will accommodate equally the needs of all interested parties and the environment. 

  • Partners include:
    • The City of Calgary, 
    • Rocky View County, 
    • The Town of Strathmore, and 
    • The Western Irrigation District (WID). 
  • Alberta Environment & Protected Areas (AEPA) participates as an observer. 
  • WaterSMART Solutions Ltd. is the facilitator and advisor. 
  • MPE Engineering Ltd. continues to support the project’s engineering requirements. 
  • Dentons Canada LLP and Bishop & McKenzie LLP provides legal services, including development of key Agreements needed to implement the CSMI governance principles. 

In winter 2018, the CSMI Master Stormwater Agreement was signed by all four partners, committing the group to proceed with development of subsequent Agreements for Development, Management, and Use of the stormwater system. These Agreements, which must be ratified by all partners to take effect, are essential for defining how the CSMI system will be built, managed, and used by the partners. Partners completed these Agreements in late 2020 as per the CSMI Master Stormwater Agreement. CSMI was incorporated in early December 2020, marking the formal establishment of an innovative and collaborative approach for a regional stormwater solution.  

Proposed solution

Stormwater drainage solutions are needed for the CSMI region because there are limited natural drainage courses to effectively transfer stormwater. After several years of collaborating, innovating and completing engineering assessments to determine how to collect and treat stormwater before it is returned to rivers, it was decided that the most feasible option for developing a regional stormwater system is an “out of canal” option. “Out of canal” means that water is kept out of the WID irrigation main canals and reservoirs and flows through an independent system. This solution combines existing and new infrastructure to divert stormwater runoff away from the main irrigation delivery system, treat it as necessary through stormwater Best Management Practices (BMPs), and eventually release it to a natural water course. 


Through development and implementation of the CSMI System, municipal and irrigation sectors are working together and sharing resources to develop a mutually beneficial solution. The shared solution will achieve a sustainable stormwater system that: 

  • Meets or exceeds regulatory standards for water quality and quantity. 
  • Meets outlet standards for eventual release to the South Saskatchewan River Basin. 
  • Ensures that new and existing infrastructure are thoughtfully integrated into a regional system. 
  • Adopts a collaborative and fair approach to management and funding of the system based on relative use of the system. 
  • Is developed in phases, using a transparent and fact-based process.

In addition to the above stormwater benefits, the CSMI is a unique project that will provide a process for ongoing collaboration between municipalities and the irrigation district for decades to come. Water flows across political boundaries, bringing people and organizations together to manage one of our most valuable resources. The relationships built throughout this collaborative process will support continued economic growth, a vibrant agricultural economy, and the long-term health of regional water resources. 


The map below shows the boundaries of the CSMI region, the development areas of the municipalities, and the proposed location of CSMI infrastructure.  The location of infrastructure is conceptual and subject to change once the CSMI partners begin engagement and consultation with specific landowners in the region, complete the final design, and apply for regulatory approval. Click to clarify and enlarge the photo.

CSMI Map 2