The Board of Soil and Water Resources established the Carnelian-Marine Watershed District in June of 1981. The District was formed to address property damage being caused by fluctuating water levels on Big Marine, Big Carnelian, and Little Carnelian Lakes.

In 2001, the Marine Water Management Organization proposed a merger with the Carnelian-Marine Watershed District. Over the next six years, discussions were held with Marine, May, Scandia, and Stillwater Township. Washington County agreed to petition for the expansion of the Carnelian-Marine Watershed District on behalf of these local governments and to include the northeast portion of Washington County that was not within any water management organization’s jurisdiction.

In 2007, the Board of Soil and Water Resources accepted the petition, expanded the district, and renamed it the Carnelian-Marine-Saint Croix Watershed District.

The Carnelian-Marine-St. Croix Watershed now encompasses 81 square miles, stretching along the St. Croix River from Stillwater Township to north of Scandia. The watershed is home to 31 lakes, three designated trout streams, hundreds of acres of wetlands and more than 17 miles of St. Croix River shoreline.