Sentinel Lake Assessment Report St. Olaf Lake (81-0003) Waseca County, Minnesota

The Minnesota Pollution Control Agency (MPCA) is working in partnership with the Minnesota Depart-ment of Natural Resources (MDNR) on the Sustaining Lakes in a Changing Environment (SLICE) Senti-nel 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 2010). To increase our ability to predict the con-sequences 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 typically do not stratify and are well mixed throughout most of the summer. "Cold Water" lakes are defined as lakes that 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 funded by the ETF. Saint Olaf represents a deep lake in the Western Corn Belt Plains (WCBP) ecoregion. Saint Olaf is a 36-hectare (89 acre) lake, located about three miles northeast of the city of New Richland, Waseca County, within the Minnesota River basin watershed. The lake has a maximum depth of 10 meters (33 feet) and a mean depth of 4.4 meters (14.5 feet). The lake is 57 percent littoral with one public access. The total con-tributing watershed for St. Olaf Lake is quite small at 77 hectares (189 acres). The watershed is predomi-nately cultivated; however the nearshore riparian area is ringed by homes and is somewhat wooded as well.