Abstract
Acknowledgements
This study and report were a culmination of many efforts from the Wisconsin Department of Natural Resources, the University of Wisconsin Stevens Point, the Waupaca Learning Center, the City of Waupaca, Waupaca’s City Government, and its citizens. Thank you all for the direction provided. Special thanks to:
§ Dave Furstenburg, Richard Pearson, and all the students who helped at the Waupaca Learning Center.
§ Daves co-presenter here
§ John Edlebeck, Waupaca Director of Public Works, whose devotion to the project and to his community were most appreciated
§ Wisconsin Department of Natural Resources, the City of Waupaca, The University of Wisconsin Stevens Point, and the Center for Watershed Science and Education whose funding allowed for the Mirror and Shadow Lake Study.
§ Nancy Turyk, whose help on data examination, report writing and editing, and Lake event scheduling was integral for the completion of the study.
§ Dr. Paul McGinley, University of Wisconsin Stevens Point, for guidance with data analysis and computer modeling.
§ Linda Stoll, and her organizational skills and experience in lake public relations.
§ Bruce Bushweiler, Waupaca County Conservationist whose helpful insights into public relations could not have been done without.
§ To the residents of Mirror and Shadow Lake for their willful and involved participation and use of the Lake Study.
§ Dick Stephen, for the water analysis done in the lab as well as help with data interpretation.
§ Jim Licari, Kandace Waldmann, Deb Sisk, and all the members of Water and Environmental Analysis Lab for their excellent work processing water samples.
Table of Contents
Abstract 1
Acknowledgements 2
Table of Contents 3
List of Table 5
List of Figures: 6
Introduction: 7
Physical characterIstics and developement 7
Setting 7
Lake Morphology 7
Geology 8
Cultural Development 8
Study goals and OBJECTIVES: 10
Methods 11
Sampling Strategy 11
Lake MeasUrements 11
INFLOW/OUTFLOW MEASUREMENTS 11
Sampling Procedures 11
Flow Measurement 12
Pressure Transducers 12
GROUNDWATER MEASUREMENTS 12
Mini Piezometers 13
Quality Control 14
METADATA 14
Spatial Analysis 14
Computer Modeling 14
Results And Discussion 15
LAKE HYDROLOGY – WHERE THE WATER IS COMING FROM 15
Precipitation 15
Surface Watersheds 15
Groundwatersheds 17
Surface Water Quality 19
Mid Lake Measurements 19
Dissolved Oxygen and Temperature 19
pH 25
Alkalinity and Hardness 27
Conductivity 28
Chloride 30
Potassium & Sodium 30
Sulfate 31
Water Clarity 31
Algae Populations 33
Nitrogen 33
Total Nitrogen to Total Phosphorus Ratio 35
Phosphorus 36
Inflow Outflow Water Quality 38
Total Suspended Solids (TSS) 39
Nitrogen 40
Phosphorus 40
Chloride 41
Groundwater 42
Groundwater Inflow and Outflow 43
Temperature 44
Conductivity 46
pH 46
Nitrate+Nitrite 46
Chloride 47
Reactive P 47
Ammonium 49
Metals 49
COMPUTER MODELING 51
SIMULATING LAND USE IMPACTS ON PHOSPHORUS TRANSFER 51
Simulation Approaches 51
Export Coefficients 52
Impervious Area Estimate 52
Pervious/Impervious/Storm Simulation Method 52
Notes 53
cONCULSIONS and Recomendations 55
INFLOW AND OUTFLOW 55
Shadow Lake 55
Mirror Lake 55
MID LAKE 55
Shadow Lake 55
Mirror Lake 55
GROUNDWATER 56
Mirror Lake 56
Shadow Lake 56
SHORELINE PRACTICES 56
LAKE MANGEMENT AT THE WATERSHED LEVEL 56
TESTING PROTOCOL 57
LOOKING TOWARDS THE FUTURE 57
WORKS CITED 58
List of Table
Format type: Level 1
Analytical Methods Used at WEAL for the Mirror and Shadow Lake Water Quality Samples and Corresponding Detection Limits. 14
Types and percent of impervious surfaces within the Mirror and Shadow Lake watersheds. 15
Mirror and Shadow Lakes Hardness Levels Waupaca, WI. 27
Measurements of turbidity, color, and water clarity during 31
overturn on Mirror & Shadow Lake Waupaca, WI. 31
Mirror Lake nitrogen concentrations throughout the year. 34
Shadow Lake nitrogen concentration throughout the year. 34
Mirror Lake nitrogen to total phosphorus ration. 35
Shadow Lakes total nitrogen to total phosphorus ratio. 35
Concentrations of soluble reactive phosphorus and total phosphorus in mid lake samples collected from Mirror Lake. 37
Concentrations of soluble reactive phosphorus and total phosphorus in mid lake samples collected from Shadow Lake. 37
Phosphorus Load Estimates for Mirror and Shadow Lakes 53
List of Figures:
Format type: List
Mirror and Shadow Lake Ground water movement and shed of Mirror and Shadow Lake, Waupaca, WI. 18
Shadow and Mirror Lake groundwatershed and associated land use Waupaca, WI 2000. 19
Seasonal temperature variation causing the stratification and mixing of many Wisconsin Lakes (Shaw et al., 2000). 21
Profile of Mirror Lake’s yearly temperatures fluctuations. 22
Profile of Mirror Lake’s yearly dissolved oxygen fluctuations. 23
Profile of Shadow Lake’s conductivity throughout the year. 30
Mirror and Shadow Lake water clarity readings and Chlorophyll A concentrations. 32
Shadow and Mirror Lake nutrient budget from the various sources of inflow and outflow. 41
Groundwater Mini-Piezometer Flow Measurements Around Mirror Lake Waupaca, WI. 43
Shadow Lake Groundwater Flow Measurements Waupaca, WI. 44
Groundwater temperatures measured from mini-piezometers around Mirror Lake Waupaca, WI. 45
Groundwater temperatures measured from mini piezometers around Shadow Lake Waupaca, WI. 46
Mirror Lake groundwater reactive phosphorus concentrations Waupaca, WI 2003. 48
Shadow Lake groundwater reactive phosphorus concentrations Waupaca, WI 2003. 49
Introduction:
Physical characterIstics and developement
Setting
Mirror and Shadow Lake are located within the central Wisconsin city of Waupaca in Waupaca County. Waupaca has a population of 6,000 people and neighbors the cities of Stevens Point, 30 miles to its northwest, and Green Bay, 60 miles to the northeast. Roads surround both the lakes and residential development occurs along the majority of the land adjacent to Mirror Lake and the land adjacent to the east shore of Shadow Lake. South Park, a city park, is located on the west side of Mirror and Shadow Lake and provides access to the lake, a boat landing, a swimming beach, picnic areas, and washroom facilities. The City of Waupaca has a municipal well located on the east shore of Mirror Lake, and throughout time has relied on the groundwater that feeds it to help supply water to the City. Finally, the Lakeside Memorial Park cemetery perches on the northwestern shore of Shadow Lake.
Lake Morphology
Mirror Lake is an oblong lake located to the north of Shadow Lake (Figure ). It is a 13 acre groundwater drainage lake with a max depth of 43 feet, and a mean depth of 25 feet. It has a small littoral zone with a steep lake bottom that quickly descends to greater depths. Mirror Lake resides in a bowl like depression that opens up on the Lake’s southern shoreline to drain to Shadow Lake through a manmade channel.
Shadow Lake is a 43 acre drainage lake with a max depth of 41 feet and a mean depth of 17 feet. Hills reside on its northern expanse, which slope into wetlands along its southern shore. Shadow Lake had a man made channel that outflows to the Crystal River located a quarter mile to the south of Shadow Lake.
Geology
A 1973 study found that Mirror and Shadow Lake’s basins were likely formed in the outwash plain of the receding Green Bay Lobe of the Cary ice sheet that occurred in Pleistocene glaciations about 12-14,000 years ago. As this ice sheet melted or wasted back northward, large blocks of ice separated from the main glacier and remained in the newly laid glacial sediment. The ice melted within the sediment and formed glacial lakes, often called “kettle lakes” because of their morphological resemblance to kettles. Around Mirror and Shadow Lake, glacial deposits and outwash sediment of medium to coarse grained sand compose the top 50-100ft of soil and overlay 50ft of glacial till that is a variable mixture of soil, pebbles, rocks, and boulders that rests on granite bedrock (Possin 1973).
Cultural Development
Mirror and Shadow Lake likely have a long cultural history dating back to pre-settlement when Native Americans used this area for encampment. As early as the 1850s, European settlers came to this region and began development. By the early 1920s, water quality issues with Mirror and Shadow Lakes wells and surrounding groundwater were already budding. At this time, the city was striving to obtain more water while maintaining a healthy drinking water network for the growing city. However, wells were clogging with the regions fine sands and surface water drawn from Mirror Lake was shown to need treatment in order to serve as a source of drinking water (Alvord and Burdick, 1921). These wells still are present on the shores of Mirror Lake today, but contribute to the City’s water supply on a much smaller scale; one being completely out of use. The inflows and outflows to Mirror and Shadow Lake have also been changed several times throughout their history. According to changes in drawings and air photos, sometime between the 1930s and 50s, an outflow was dredged at the south end of Shadow Lake to allow access from the Crystal River. Much more recently, the outflow from Mirror to Shadow Lake was dredged to provide access between the Lakes. Naturally, these outflows appear to have been much smaller wetland streams. In addition to these flows, an inflow was added to the north end of Shadow Lake to transport drainage water from the city to Shadow Lake. As early as 1935, residences and streets surrounded Mirror Lake and by 1960 the land adjacent to the east shore of Shadow Lake was developed. By this time in the 1960s, both lakes were considered urban as they picked up residence in the growing city of Waupaca, WI.
In the mid 1970s Garrison completed a study of Mirror and Shadow Lake that showed evidence of cultural eutrophicaiton. Consistent with studies elsewhere, runoff from streets, lawns, and rooftops, were found to be adding dissolved nutrients and metals to Mirror and Shadow Lake. Eutrophication brought about excessive algal and plant growth, and decreased dissolved oxygen concentrations. Data showed that the reduction of nutrients and metals to the Lakes was necessary and lead to the diversion of storm sewers away from the Lakes in 1976. In 1978, aluminum sulfate was applied to the Lakes to enhance recovery rates by reducing internal phosphorus loading (Aluminum forms a precipitate with phosphorus that can reduce its availability to aquatic plants and algae). It was estimated that the implementation of storm sewer diversion reduced external phosphorus loading by approximately 58 to 65 % for both lakes. The aluminum sulfate application reduced in-lake phosphorus concentrations from 90 mg/m3 in Mirror Lake and 33 mg/m3 in Shadow Lake to 20 to 25 mg/m3 in both lakes. Along with these treatments, Mirror Lake was artificially aerated to prevent low winter dissolved oxygen concentrations and increase spring oxygen concentrations (Garrison and Knauer 1981).
Much more currently, Adopt-a-Lake Program members had been monitoring water quality on Mirror and Shadow Lake along with Dave Furstenburg and his students from the Waupaca Learning Center. They and the Department of Public Works, the City of Waupaca’s Lakes District, and the Wisconsin Department of Natural Resources (WDNR) gathered a body of four years of information about each lake. They became concerned when they found low dissolved oxygen concentrations in Mirror Lake. They determined these conditions were occurring because of Mirror Lake’s depth, narrow vegetative border, wind-sheltered surface, and lack of circulation. In February of 2001 Mirror Lake suffered a winter fish kill due to these low dissolved oxygen concentrations. Recent monitoring showed problems remain in Mirror and Shadow Lake leading to the procurement of funds for a lake studies.
A partnership between the City of Waupaca, Mirror and Shadow Lake Watchers Adopt-A-Lake group, UW-Stevens Point, and the Fox-Wolf Watershed Alliance was formed and a study design was determined. In 2002, funds were provided for the study by the WDNR Lake Planning Grant Program, the City of Waupaca, and the University of Wisconsin Stevens Point (UWSP) Center for Watershed Science and Education (CWSE).
Study goals and OBJECTIVES:
§ Estimate a water budget for the Lakes and determine the land areas impacting surface and groundwater feeding the lakes.
§ Determine the current quality of surface water inlet, outlets, and groundwater in both Mirror and Shadow Lakes over an annual cycle.
§ Produce a preliminary nutrient budget and the relationships between water quality and land use.
§ Provide educational opportunities for lake landowners to participate in parts of the study and enhance their understanding of the lake and its drainage/watershed and a workshop on shoreline management practices.
§ Summarize results in an understandable format to be used by residents and agency personnel to acquire a better understanding of the Shadow and Mirror Lakes and how their land use practices may affect water quality in the streams and lakes providing recommendations to assist future lake management decisions.
§ Create an updated management and implementation plan for the two lakes and provide data for the update of the county Land and Water Resource Plan.
§ Identify data the Lake Watchers Adopt-a Lake group could collect that would be useful for long-term monitoring of the lakes. Develop a quality assurance plan for this collection effort.
§ Assess current shoreline management including an updated shoreline land cover and littoral zone.
§ Work with the City of Waupaca Lake District to form an advisory committee to provide pertinent water data and information to assist the Lake District in comprehensive (“smart growth”) management to develop any needed changes to ordinances and city plans by providing suggestions for the prioritization of city restoration money.
§ Incorporate the Adopt-A-Lake group in the collection of data and outreach components of the study.
Methods
Sampling Strategy
Sampling was conducted in a manner to provide data from groundwater and surface water that would demonstrate their current status. This included sampling them throughout the year as climate changed to enumerate variation that was occuring. Sampling periods occurred during the spring thaw, spring turnover, growing season, fall turnover, and winter settings. In each of these periods, when climatic conditions changed, sampling also occurred. For example, in the growing season when precipitation becomes limited, a rainstorm would provide the opportunity for sampling to occur. In this way, as much variation as possible was captured to allow greater and more accurate interpretation of the system.