Presented to: Reitz Lake Open House July 12, 2005

1. Metropolitan Council Environmental Services Lake Ecology and Water Quality andReitz Lake Presented to: Reitz Lake Open House July 12, 2005 Randy Anhorn Principle Environmental Scientist Metropolitan Council Environmental Services randy.anhorn@metc.state.mn.us 651.602.8743

2. Minnesotans are passionate about their lakes and rivers “Look! What a Peach I Landed–and How!” Greetings from Big Sandy Lake

3. Metropolitan Council Environmental Services Ecology and Biology of Lakes

4. Minnesota Ecoregions Summer Average Water Quality Values North Central Hardwood Forest TP Cla Secchi Percentile (mg/l) (mg/l) (m) 25-75 23-50 5-22 1.5-3.2 Western Corn Belt Plains TP Cla Secchi Percentile (mg/l) (mg/l) (m) 25-75 65-150 30-80 0.5-1.0

5. Metropolitan Council Environmental Services Physiographic Lake Regions in the Twin Cities Metropolitan Area

6. warm, light water Epilimnion (Mixed Layer) 0-4 meters Metalimnion Hypolimnion 4-17 meters Thermocline(prevents mixing) (cool, heavy water) Diagram not to scale Generalized Lake Ecosystem (Summertime Average Conditions)

7. Littoral Community Aquatic plants dominant Limnetic Community Area of open water;habitat of algae, zooplankton and fish Profundal Community Area of no light penetration;domain of bacteria and fungi Lake Communities

8. Metropolitan Council Environmental Services Reitz Lake is in the Carver Creek Watershed. Carver Creek discharges to the Minnesota River

9. More Development(impervious surface) = More Runoff

10. Water Quality The idea of lake water quality is tied to a concept of aging or “Eutrophication”

11. Oligotrophic lake:few nutrients, little aquatic vegetation Mesotrophic lake:sedimentation, increased nutrient levels,more abundant aquatic vegetation Eutrophic lake:basin nearly filled with sediment, high nutrient levels, dense aquatic vegetation Lake Aging Process Nautral Eutrophication, caused by nutrient-rich nonpoint source runoff and growth and decay of aquatic vegetation Centuries Cultural Eutrophication accelerates the aging process by introducing nutrient-rich point source and additional nonpoint source runoff from human activities Decades

12. General Trophic Classification of Lakes Oligotrophic Mesotrophic Eutrophic Reitz Lake TotalPhosphorus (m g/l) Chlorophyll-a(m g/l) SecchiTransparency(m) <12 13-25 >26 ~100 <3 3-7 >8 ~ 45 >4 2-4 <2 ~ 2

13. Relative Costs of Lake Restoration versus Prevention Lake Restoration after Serious Degradation Extensive Lake Management Costs Limited Lake Management Simple Prevention and Protection 0 Corrective Measures

14. Reitz Lake DNR ID # 10-0052 Surface area: 79 acres Watershed area: 3,600 acres W-to-S ratio 46:1 Maximum depth 11.0 m (36 ft) Mean depth 4.0 m (13 ft) Volume of water 1,027 ac-ft % littoral 58% Thermocline Yes

18. Lake QualityReport Card System Grade Percentile TP (mg/l) CLA (mg/l) Secchi (m) A <10 <23 <10 >3.0 B 10-30 23-32 10-20 2.2-3.0 C 30/70 32-68 20-481.2-2.2 D 70-90 68-152 48-77 0.7-1.2 F >90 >152 >77 <0.7

19. Reitz Lake Water Quality Grades Based on Summer Means

20. 2004 Lake Grades CAMP and Metropolitan Council Monitored Lakes

21. Using Satellite Technology to Assess Regional Water Quality on an Annual Basis

22. Invasive Species Zebra Mussels Curly-leaf Pondweed Purple Loosestrife Eurasian Watermilfoil

23. Some Internet Sites of Note www.co.carver.mn.us/water/ (Carver County Environmental Services) www.metrocouncil.org/environment/index.htm (Metropolitan Council) annual lake report-/environment /RiversLakes/Lakes/index.htm annual WQ Summary- /planning/environment/environment/LWQ2004.pdf annual Satellite Summary-/planning/environment/environment/TCWaterClarity2004.pdf www.pca.mn.us (Minnesota Pollution Control Agency) www.dnr.state.mn.us/lakefind/ (Minnesota Dept. of Natural Resources) www.bwsr.state.mn.us (Board of Water and Soil Resources) www.mnlakes.org (Minnesota Lakes Association) www.shorelandmanagement.org Randy Anhorn randy.anhorn@metc.state.mn.us 651.602.8743