Opuntia Lake is a large, saline, shallow lake location in the mixed-grass prairie ecoregion of Saskatchewan and was formed by a Prairie farm Rehabilitation Administration damn on Eagle Creek. Mudflats are formed by the low water levels in summer. Steep clay banks with rocky, sandy areas form the East shoreline. There are no islands on this lake and the open water is turbid. Blue-green algae blooms occur infrequently.
Emergent vegetation includes bulrush and sedge.
Submergent vegetation consists of pondweeds in deep water and water milfoil in the shallow water. Upland surrounding the lake consists of grassland. There aren t many breeding and moulting dabbler and divers. Ring-billed Gulls, Eared Grebes and several shorebird species are also common visitors. The sanctuary is protected by Migratory Bird Sanctuary Regulations under the Migratory Bird Conservation Act.