Six Mile Creek-Halsted Bay Habitat Restoration

Overview

From 2014 to 2023, the Minnehaha Creek Watershed District (MCWD) and its partners conducted one of the region’s largest habitat restoration and water quality enhancement programs. The program aimed to improve water quality and aquatic vegetation conditions in the Six Mile Creek-Halsted Bay Subwatershed (SMCHB)‘s 14-lake system by managing common carp populations. Introduced to Minnesota in the 1880s, carp are one of the most damaging aquatic invasive species in our waters; they uproot aquatic vegetation, dig up nutrient-rich sediment (releasing phosphorus and other nutrients that contribute to algae blooms), and compete with native fish and waterfowl for food. MCWD sought to restore 2,488 acres of in-lake habitat across deep and shallow lakes and create corridors of restored wetland and uplands near Six Mile Creek, one of Lake Minnetonka’s largest tributaries. 

The foundation for this program was a 3-year carp assessment conducted in partnership with the University of Minnesota Aquatic Invasive Species Research Center (MAISRC), which evaluated common carp’s abundance, recruitment patterns, and seasonal movement patterns in the SMCHB Subwatershed. The assessment informed a three-pronged management strategy that included the construction of barriers to impede carp migration, aeration in known spawning areas to prevent winterkill of carp egg predators, and carp removal. Our efforts successfully limited carp populations across the system, improving habitat for native fish, waterfowl, and other wildlife, while enhancing recreation opportunities. However, the system’s lakes have shown varied vegetation and water quality benefits. These nuanced impacts suggest a need to continue studying the factors that influence carp management efficacy across diverse lake systems.