Water Retention within the Lake Winnipeg Basin with Sioux Valley Dakota Nation

The Assiniboine West Watershed District is partnering with the Sioux Valley Dakota Nation to undertake a water retention project on Sioux Valley lands in southwestern Manitoba. The proposed project will capture excess spring runoff from annual crop and pasture land. Holding the water back on the landscape will reduce nutrient loading to the Assiniboine River and Lake Winnipeg, and provide long-term flood protection and enhance drought resilience for the Sioux Valley Dakota Nation. Construction will take place in the summer when the stream channel is dry so as to avoid any potential negative impacts on water quality and aquatic habitat while water runs through the creek during spring melt and summer runoff events. To create the water retention site, the site will be excavated to a size of approximately 15ft deep x 30ft wide x 100ft long, and a small earthen dam will be created that stretches across the shallow ravine to hold more spring runoff and excess. A bulldozer will be used to create a 3:1 side slope (upstream) and a 4:1 side slope (downstream) structure with a 3m wide top perpendicular to the channel. An emergency spillway channel will be constructed in a horseshoe shape and lined with rip-rap rock to a design standard of 1 in 100 year flood frequency. The area around the excavated area, including the banks and top of the dam will be planted with native wetland plants to create habitat for wildlife and birds and to prevent/reduce soil erosion. The Assiniboine West Watershed District has built over 75 structures of a similar design over the last 15 years, and has overseen all aspects of the project including licensing, construction, erosion control, re-vegetation and future water quality protection (including livestock access).

Latest update

June 04, 2021 - The assessment decision statement has been issued to the proponent.


Key documents

Key documents
Document Number Document Title File Date
1 Water Retention within the Lake Winnipeg Basin with Sioux Valley Dakota Nation PDF (16 KB) January 29, 2021


Environment and Climate Change Canada
Dana Hay, Senior Program Officer
Winnipeg, Manitoba
Telephone: 204-983-7040
Email: dana.hay@canada.ca

  • Location

    • Sioux Valley Dakota Nation (Manitoba)
  • Nature of Activity

    • Water Management
    • Remediation and conservation
  • Assessment Status

  • Start Date

  • Proponent

    Assiniboine West Watershed District
  • Authorities

    • Environment and Climate Change Canada
  • Assessment Type

    Project on federal lands
  • Reference Number


This map is for illustrative purposes. The markers represent the approximate locations based on available data. More than one marker may be identified for a given assessment.


Nearby assessments

...within 200 kilometres
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