Water Quality Assessment of Select Lakes within the Little Fork River Watershed

This report is a summary of available water quality data for lakes within the Little Fork River watershed. The watershed approach is a ten-year rotation for assessing waters of the state on the level of Minnesota's 81 major watersheds. The primary feature of the watershed approach is that it provides a unifying focus on the water resources within a watershed as the starting point for water quality assessment, planning, and results measures. The major benefit of this approach is the integration of monitoring resources to provide a more complete and systematic assessment of water quality at a geographic scale useful for the development and implementation of effective restoration and protection strategies. The Minnesota Pollution Control Agency (MPCA) is in the process of aligning its lake monitoring efforts with the major watershed monitoring schedule. Though the MPCA began its ten-year monitoring cycle in 2008, lake monitoring activities were not aligned to this ten-year cycle until 2009. As such, we have limited lake data on which to report at this time. MPCA monitoring of large lakes within the Little Fork watershed will be conducted in 2010-2011. This report will describe all data available at this time. It will be updated in 2012 to include 2010-2011 lake monitoring results. The Little Fork River watershed drains an area of 4,773 square kilometers (1,843 square miles) in northeast Minnesota. A total of 11 sub-watersheds (HUC-11) comprise the entire watershed. The headwaters start on the north side of the Laurentian divide in Itasca and St. Louis Counties. Forest and wetlands (principally peatlands) are the major land cover classifications in the watershed. The Little Fork River watershed lies within the Northern Lakes and Forest (NLF) and Northern Minnesota Wetland ecoregions. There are approximately 125 natural lakes greater than four hectares (ten acres) in the watershed, with most located in the Bear River and Sturgeon Lake sub-watersheds. In general, lake water quality data are sparse in the watershed, with most lakes having little or no historical water quality data collected. Only 14 lakes have assessment level data. The University of Minnesota has estimated Secchi disk (SD) transparency on all Minnesota lakes greater than four hectares (ten acres), using satellite imagery. Approximately 95 percent of Little Fork watershed lakes have estimated transparences between 1.4 – 4.5 meters (m), with a mean of 3.0 m. In general, estimated SD values indicate good water clarity in the basin, particularly the lakes of the Sturgeon chain and the headwater lakes of the Bear River on the western border of the watershed. Large, shallow wild rice lakes, such as Nett and Big Rice, were estimated to