Sentinel Lake Assessment Report South Center Lake (13-0027) Chisago County, Minnesota

The Minnesota Pollution Control Agency (MPCA) is working in partnership with the Minnesota Department of Natural Resources (MDNR) on the Sustaining Lakes in a Changing Environment (SLICE) Sentinel Lakes Program. The focus of this interdisciplinary effort is to improve understanding of how major drivers of change such as development, agriculture, climate change, and invasive species can affect lake habitats and fish populations, and to develop a long-term strategy to collect the necessary information to detect undesirable changes in Minnesota Lakes (Valley 2009). To increase our ability to predict the consequences of land cover and climate change on lake habitats, SLICE utilizes intensive lake monitoring strategies on a wide range of representative Minnesota lakes. This includes analyzing relevant land cover and land use, identifying climate stressors, and monitoring the effects on the lake's habitat and biological communities. The Sentinel Lakes Program has selected 24 lakes for long-term intensive lake monitoring (Figure 1). The "Deep" lakes typically stratify during the summer months only. "Shallow" lakes are defined as mixing continuously throughout the summer. "Cold Water" lakes are defined as lakes that either harbor cisco, lake whitefish, or lake trout and are the focus of research funded by the Environmental Trust Fund (ETF). "Super sentinel" lakes also harbor cold-water fish populations and research on these lakes is also funded by the ETF. South Center Lake is located in Chisago County within the St. Croix River (Stillwater) watershed. The lake is part of the Chisago Lakes Chain that is located near Lindstrom and Center City, Minnesota (MN). South Center Lake is unique because of its great depth and large littoral area (67%). South Center Lake is a popular recreation lake that has a surface area of 336 hectare (830 acres) and has a maximum depth of 30.5 meters (100 ft); however, its size and depth has a tendency to vary with groundwater levels and precipitation. South Center Lake is a dimictic lake that stratifies during the summer. Nearly all of the shoreline of South Center Lake is developed, with approximately 332 homes around the lake's shore in 2005. The public access, although large, can be filled to capacity at times. The lake supports a large range of water based recreational activities.