Large man-made reservoir created by damming Owl Creek. A couple of small islands provide important gull and tern nesting habitat. Just upstream of the reservoir, a flooded cottonwood riparian area supports nesting herons.

(NOTE: the upstream cottonwood riparian area includes T10N R3E section 33 SW quarter of SW quarter, and section 32 SE quarter)

Ornithological Summary

This is the only gull/tern colony in the western part of the state and in some years, is the largest gull/tern colony in the state. During higher water years, cottonwood forest just upstream of the reservoir floods and hosts one of the largest heron colonies in the state. Both Herring Gull and Caspian Tern have begun nesting here recently; a significant expansion of the breeding range of these species in the state.

Conservation Issues

Boating, water-skiing, and fishing are extremely popular during the summer; sometimes these recreationist land on the nesting islands to picnic, sunbathe, and play. Water levels are manipulated to supply irrigation to surrounding areas.  Nesting islands can become overgrown with vegetation and no longer suitable for nesting.


The waters and the islands are owned by either Bureau of Reclamation (BOR) or the state of South Dakota. Surrounding land is part state park and part leased to ranchers by BOR.


Large open-water reservoir with a couple of islands. During periods of low water, extensive mud flats. Upstream features a bit of cottonwood forest and some small marshes.

Land Use

Reservoir heavily used for boating and fishing recreation. Some of surrounding land is a state park/campground; the rest is pastureland or CRP grassland.

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