Bloody Slayton Lime Bingham Talcot Windom Cottonwood Status and Trend Monitoring of Selected Lakes in Cottonwood and Murray Counties 2007 Environmental Analysis and Outcomes Division Water Assessment and Environmental Information Section December 2008 Minnesota Pollution Control Agency 520 Lafayette Road North Saint Paul, MN 55155-4194 http://www.pca.state.mn.us 651-296-6300 or 800-657-3864 toll free TTY 651-282-5332 or 800-657-3864 toll free Available in alternative formats Authors Kelly O’Hara Lake Assessment Program 2007 Status and Trend Monitoring of Selected Lakes in Cottonwood and Murray Counties Minnesota Pollution Control Agency Environmental Analysis and Outcomes Division Water Assessment and Environmental Information Section Lake Name Lake DOW#ID Bingham 17-0007 Cottonwood 17-0022 Talcot 17-0060 Lime 51-0024 Bloody 51-0040 wq-lar3-15 The MPCA is reducing printing and mailing costs by using the Internet to distribute reports and information to wider audience. For additional information, see the Web site: www.pca.state.mn.us/water/lakereport.html. Table of Contents Introduction......................................................................................................................................1 Background......................................................................................................................................3 Watersheds.......................................................................................................................................3 Lake Level Trends ...........................................................................................................................3 Precipitation .....................................................................................................................................4 Fisheries ...........................................................................................................................................5 Methods ...........................................................................................................................................8 Results ...........................................................................................................................................9 Bingham.....................................................................................................................................9 Cottonwood..............................................................................................................................11 Talcot .......................................................................................................................................13 Lime .........................................................................................................................................15 Bloody......................................................................................................................................17 Trophic State Index........................................................................................................................19 Trophic Status Trend Data.............................................................................................................19 Modeling........................................................................................................................................20 Goal Setting ...................................................................................................................................20 Appendices.....................................................................................................................................25 A. Glossary .............................................................................................................................25 B. Water Quality Date Abbreviations and Units ....................................................................27 C. References..........................................................................................................................28 D. Surface Quality Water Results...........................................................................................29 List of Tables 1 Lake Morphometry and Watershed Characteristics................................................................6 2 Watershed Land Use as Compared to Ecoregion Interquartile Ranges..................................6 3 2007 Lake Summer Mean Water Quality ...............................................................................8 4 Eutrophication Standard by Ecoregion and Lake Type ........................................................21 5 Cottonwood and Murray County Lakes Aquatic Recreational Use Comparison.................22 6 MINLEAP Model Results.....................................................................................................23 List of Figures Figure Page 1 Minnesota’s Seven Ecoregions as Mapped by U.S. EPA.......................................................2 2 Summer 2007 Rainfall Based on Records for the Talcot Lake Area......................................4 3 Water Year Precipitation and Departure from Normal for 2007 ............................................4 4 Land Use for Lake in Cottonwood and Murray Counties.......................................................7 5 Bingham Lake Dissolved Oxygen and Temperature Profiles.................................................9 6 Bingham Lake TP (Surface and Hypolimnetic), Chl-a, and Secchi Depth ..........................10 7 Cottonwood Lake Dissolved Oxygen and Temperature Profiles .........................................11 8 Cottonwood Lake TP (Surface and hypolimnetic), Chl-a, and Secchi Depth......................12 9 Talcot Lake Dissolved Oxygen and Temperature Profiles...................................................13 10 Talcot Lake TP and Chl-a Concentrations and Secchi Depth ..............................................14 11 Lime Lake Dissolved Oxygen and Temperature Profiles.....................................................15 12 Lime Lake TP and Chl-a Concentrations and Secchi Depth ................................................16 13 Bloody Lake Dissolved Oxygen and Temperature Profiles .................................................17 14 Bloody Lake TP and Chl-a Concentrations and Secchi Depth.............................................18 15 Trophic Status Trends for Cottonwood and Murray County Lakes .....................................19 16 Carlson’s 2007 Trophic State Index for Cottonwood and Murray County Lakes................24 Introduction The Minnesota Pollution Control Agency’s (MPCA) core lake monitoring programs include Legacy Lake Monitoring, the Citizen Lake Monitoring Program (CLMP) and Lake Assessment program (LAP). In addition to these programs, the MPCA annually monitors numerous lakes to provide baseline water quality data, provide data for potential LAP and Clean Water Partnership (CWP) lakes, characterize lake condition in different regions of the state, examine year-to-year variability in ecoregion-reference lakes, provide additional trophic status data for lakes exhibiting trends in Secchi transparency and to provide data for the protection, restoration, and preservation of Minnesota surface waters through the Clean Water Legacy Act (CWLA). In the latter case, sampling is conducted to provide data on water quality conditions to achieve and maintain established standards. To make sampling efficient, geographic clusters of lakes are selected (e.g., focus on a specific county or region) whenever possible. The MPCA prepares lake assessments under section 305(b) and 303(d) of the Clean Water Act (CWA). These assessments are done to estimate the extent to which Minnesota water bodies meet the goals of the CWA. This information is shared with planners, citizens and other partners in basin planning and watershed management activities. In the case of 303(d) assessments lakes are assessed to determine whether they meet “aquatic recreational uses”. This report details the analysis of water quality data on lakes in Cottonwood and Murray Counties. Data collected in 2007 was combined with data from previous sample seasons. For data-poor lakes, monitoring establishes a baseline data. In the selection of lakes, a focus is typically placed on large lakes, with surface areas of 500 acres or more; however, Talcot Lake was the only lake to meet the criteria. Water quality samples were collected monthly from May through September. A summary of data follows and will include data from 2007 (Appendix D). The Western Corn Belt Plains (WCBP) ecoregional values will be used for comparison in the land use (Table 2 and Figure 4) and lake summer-mean water quality (Table 3) tables. The WCBP will also be used for an input for the MINLEAP model application (Table 6). This provides a basis for placing data from these lakes in perspective relative to one another, as well as other lakes in the same ecoregion. Status and Trend Monitoring of Selected Lakes Minnesota Pollution Control Agency in Cottonwood and Murray Counties 2007 January 2009 1 Figure 1. Minnesota’s Seven Ecoregions as Mapped by U.S. EPA Status and Trend Monitoring of Selected Lakes Minnesota Pollution Control Agency in Cottonwood and Murray Counties 2007 January 2009 2 Background Lake Morphometric and Watershed Characteristics Lake morphometric characteristics including surface area mean and maximum depth and percent littoral are summarized in Tables 1 and 2. With 873 acres, Talcot Lake was the largest