Comprehensive Management Plan Update March 2021
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Town of Saint Germain Vilas County, Wisconsin Comprehensive Management Plan Update March 2021 Official First Draft Alma Lake Big St. Germain Lake Fawn Lake Lake Content Lost Lake Moon Lake Created by: Brenton Butterfield, Josephine Barlament, Eddie Heath, Heather Lutzow, Paul Garrison, & Tim Hoyman Onterra, LLC De Pere, WI Funded by: Town of Saint Germain Big Saint Germain Lake Area District Wisconsin Dept. of Natural Resources (LPL171319 & LPL171019) Acknowledgements This management planning effort was truly a team-based project and could not have been completed without the input of the following individuals: Town of Saint Germain Lakes Committee Mary Anderson Dave Kunelius Kay Schultz Don Baumann Judy Napierala Steve Soltwedel Jim Guckenberg Ted Ritter Barbara Steinhilber Gary Heeler Donna Rollmann Tony Waisbrot Milt Klingsporn Bob Schell Dave Zielinski Wisconsin Dept. of Natural Resources Kevin Gauthier Town of Saint Germain Comprehensive Management Plan - Draft 1 TABLE OF CONTENTS 1.0 Introduction ............................................................................................................................................ 5 2.0 Stakeholder Participation ....................................................................................................................... 7 3.0 Results & Discussion ........................................................................................................................... 13 3.1 Lake Water Quality .......................................................................................................................... 13 3.2 Watershed Assessment .................................................................................................................... 34 3.3 Paleoecology .................................................................................................................................... 40 3.4 Shoreland Condition ........................................................................................................................ 49 3.5 Aquatic Plants .................................................................................................................................. 60 3.6 Other Aquatic Invasive Species in the Town of Saint Germain Lakes ............................................ 86 3.7 Fisheries Data Integration ................................................................................................................ 88 4.0 Summary and Conclusions................................................................................................................. 109 5.0 Implementation Plan .......................................................................................................................... 110 6.0 Methods.............................................................................................................................................. 122 7.0 Literature Cited .................................................................................................................................. 124 8.0 Individual Lake Reports ...................................................................................................................... 128 FIGURES Figure 2.0-1. Select survey responses from the Found Lake Stakeholder Survey ....................................... 9 Figure 2.0-2. Select survey responses from the Found Lake Stakeholder Survey, continued ................... 10 Figure 2.0-3. Select survey responses from the Town of Saint Germain Lakes Stakeholder Survey ........ 11 Figure 2.0-4. Select survey responses from the Town of Saint Germain Lakes Stakeholder Survey, continued ..................................................................................................................................................... 12 Figure 3.1-1. Wisconsin Lake Classifications ........................................................................................... 18 Figure 3.1-2. Location of the Town of Saint Germain within the ecoregions of Wisconsin. .................... 19 Figure 3.1-3. WVIC reservoir system. ....................................................................................................... 20 Figure 3.1-4. Town of Saint Germain project lakes 2019 mid-summer total nitrogen to total phosphorus ratios ............................................................................................................................................................ 22 Figure 3.1-5. Town of Saint Germain project lakes summer average near-surface total phosphorus concentrations and median summer near-surface phosphorus concentrations for comparable lakes. ........ 23 Figure 3.1-6. Town of Saint Germain project lakes summer average chlorophyll-α concentrations and median summer chlorophyll-α concentrations for comparable lakes. ........................................................ 24 Figure 3.1-7. Town of Saint Germain project lakes average summer chlorophyll-α concentrations plotted against average summer total phosphorus concentrations. ......................................................................... 25 Figure 3.1-8. Town of Saint Germain project lakes summer average Secchi disk depth and median summer Secchi disk depths for comparable lakes. ................................................................................................... 26 Figure 3.1-9. Town of Saint Germain project lakes average summer Secchi disk depths plotted against average summer chlorophyll-α concentrations. .......................................................................................... 27 Figure 3.1-10. Town of Saint Germain project lakes average growing season true color values. Samples collected from the near-surface. Color range adapted from UNH Center for Freshwater Biology (2014). 27 Figure 3.1-11. Town of Saint Germain project lakes Trophic State Index. ............................................... 28 Figure 3.1-12. Town of Saint Germain project lakes mid-summer near-surface pH values. ..................... 29 Figure 3.1-13. Town of Saint Germain project lakes average total alkalinity and sensitivity to acid rain. 30 Document Information Town of 2 Saint Germain Figure 3.1-14. Town of Saint Germain project lakes average calcium concentrations and susceptibility to zebra mussel establishment. ........................................................................................................................ 31 Figure 3.1-15. Town of Saint Germain stakeholder survey responses to questions regarding how stakeholders describe lake water quality ..................................................................................................... 33 Figure 3.1-16. Town of Saint Germain stakeholder survey responses to questions regarding current and historical water quality ................................................................................................................................ 33 Figure 3.2-1. Town of Saint Germain project lakes’ watersheds within the Wisconsin River Basin. ....... 36 Figure 3.2-2. Town of Saint Germain project lakes watershed boundaries and land elevation ................. 36 Figure 3.2-3. Town of Saint Germain lakes watershed size (left) and watershed to lake area ratios (right). .................................................................................................................................................................... 37 Figure 3.2-4. Town of Saint Germain lakes watershed landcover composition. ....................................... 37 Figure 3.2-5. Town of St. Germain lakes estimated annual phosphorus loading in pounds. ..................... 38 Figure 3.2-6. Town of St. Germain lakes measured versus WiLMS-predicted in-lake growing season total phosphorus concentrations. ......................................................................................................................... 39 Figure 3.3-1. DCA plot of top/bottom samples from study lakes in the Town of Saint Germain. ............ 42 Figure 3.3-2. Changes in abundance of important diatoms found in the top and bottom of the sediment core from Alma Lake. ......................................................................................................................................... 43 Figure 3.3-3. Changes in abundance of important diatoms found in the top and bottom of the sediment core from Moon Lake. ........................................................................................................................................ 44 Figure 3.3-4. Changes in abundance of important diatoms found in the top and bottom of the sediment core from Big Saint Germain Lake. .................................................................................................................... 45 Figure 3.3-5. Changes in abundance of important diatoms found in the top and bottom of the sediment core from Found Lake......................................................................................................................................... 46 Figure 3.3-6. The Lake Diatom Condition Index (LDCI) for Alma, Big Saint Germain, Found, and Moon lakes. ........................................................................................................................................................... 46 Figure 3.4-1. Shoreland assessment category descriptions ........................................................................ 56 Figure 3.4-2. Town of Saint Germain Lakes shoreland categories ...........................................................