Notice of Intent to Make a Determination

Wahpeton Dakota Nation Sewage Lagoon Expansion - Public Comments invited

July 23, 2024 - Indigenous Services Canada must determine whether the proposed Wahpeton Dakota Nation Sewage Lagoon Expansion, to be located on Wahpeton First Nation, is likely to cause significant adverse environmental effects. To help inform this determination, Indigenous Services Canada is inviting comments from the public respecting that determination.

Written comments must be submitted by August 22 2024 to:

Indigenous Services Canada
Alvin Hamilton Building, 1783 Hamilton Street
Regina, SK  S4P 2B6

Telephone: 306-581-3134
Email: isc-skenv@sac-isc.gc.ca

Proposed Project

The Wahpeton First Nation is proposing a new Lagoon as well as upgrades and repairs to the current lagoon.  The current lagoon provides an area of 0.73 ha for treatment and a secondary cell with a capacity of 8,730 m3 for storage. Therefore, the expansion will require an additional 0.42 ha of treatment area and 10,730 m3 of storage volume to service the design population of 459 people.

Site preparation of the proposed lagoon upgrades will begin with all topsoil, loose fill and deleterious materials should be removed from the proposed construction footprint. The surface of the subgrade will be levelled and compacted and fill be used to bring the subgrade soil to the design elevation in the construction area. De-watering of the excavation is proposed to be conducted over the time-period for which the excavations are left open. Excavated soil is to be stockpiled away from the crest of the excavation.   If required, a subsurface drainage system is proposed to be installed to control groundwater levels and to facilitate the construction. Riprap is proposed around the openings of control structures to minimize the potential for surface erosion. Level control monitors should be installed to prevent overtopping of the dykes. The top of the dykes are proposed to be of sufficient width (minimum 4 m) to accommodate service vehicle access and practical construction equipment. It is recommended that crest of each dyke be capped with 100 mm of Base Coarse. A collector ditch is proposed to be excavated adjacent to the toe of the perimeter dykes for collection and controlled discharge of surface runoff. The collector ditch should be connected to the local natural surface drainage system. Slope protection could consist of riprap or manufactured erosion protection such as geotextiles or erosion control blankets.