A report for the State of Minnesota Pollution Control Agency
Prepared by:
University of Minnesota Limnological Research Center
Eugene A. Hickok & Associates
Barr Engineering Co.
Harza Engineering Company
January, 1971
Table of Contents:
Summary Letter
Table of Contents
List of Illustrations
List of Tables
Abbreviations
Useful Equivalents
Chapter I - OVERVIEW
Problems of Lake Minnetonka
Investigations
Chapter II - URBANIZATION OF THE WATERSHED
Data Sources
Projected Future Population
Urbanized Area
Chapter III - VALUE OF LAKE MINNETONKA
Public Value of the Lake
Private Value of Lake
Chapter IV - NUTRIENT BUDGET
Introduction
Sources of Phosphorus
Quantities of Phosphorus
Phosphorus Losses
Determination of Phosphorus Budgets
Discussion
Chapter V - NUTRIENT-ALGAL RELATIONSHIP
Input - Content Relationship
Interpretation of Results
Chapter VI - HYDROLOGY OF LAKE MINNETONKA
Introduction
The Hydrologic Cycle of Lake Minnetonka
Description of the watershed
Determination of Present and Historic
Hydrologic Balance
Pumpage of Ground Water and wastewater
Discharge to Lake Minnetonka
Determination of Hydrologic Balance for the Year 2000
Chapter VII - COMPARISON OF ALTERNATIVES
Wastewater Diversion Alternative
Advanced Wastewater Treatment
Summary
Chapter VIII - RECOMMENDED PLAN
Introduction
Wastewater Management
Storm Water Management
Hydrologic Surveillance
Public Relations
Chapter IX - INSTITUTIONAL FRAMEWORK
Introduction
Agency Responsibilities
Organization of Agencies
Financial Resources
Conclusions and Recommendations
Chapter X - REVIEW OF AGENCY POLICY
Announced Policy
Effect on Protection of the Lake
Hydrologic Effect of Diversion
Effect on Costs
Summary
Appendices
Appendix A - An Appendix to Chapter III
Value of Lake Minnetonka
Land Value Near Lake Minnetonka
Form of Equation
Interpretation of Equation
Appendix B - An Appendix to Chapter V
Nutrient-Algal Relationship
Phosphorus Loading and Residence Time
Phosphorus Content
Appendix C - An Appendix to Chapter VI
Hydrology of Lake Minnetonka
Introduction
Description of Basin
The Hydrologic Cycle
Hydrologic Budgets
Historical Conditions Watershed Hydrology
Future Conditions Watershed Hydrology
Average Year Surface Water Balance for Lake Minnetonka
LIST OF ILLUSTRATIONS
Population Within the Watershed
Urbanized Areas - 1969
Urbanized Areas - 1985
Urbanized Areas - 2000
Phosphorus Loading vs. Mean Depth
The Hydrologic Cycle
Unit Costs of Phosphorus Removal with Alum
Unit Costs of Phosphorus Removal with Alum
Unit Costs of Phosphorus Removal with Lime
The Hydrologic Cycle
Jordan Aquifer Piezometric Contours - 1958
Outflow at Grays Bay vs. Crow River
Outflow at Grays Bay vs. Precipitation
Geologic Section
Pumping centers and Area Affected
Average Overflow of Lake Minnetonka
Drought Lake Levels
Population in Lake Minnetonka Watershed
Lake Minnetonka Beaches
Marinas and Yacht Clubs
Public Boat Launching Facilities
Ice Fishing Houses
Average Land Values
Strength of Septic Tank contents
Lake Minnetonka Nutrient Budget - 1969-1970
Relative Importance of Phosphorus Sources
Estimated Phosphorus Inputs from Treatment Plants in Year 2000
Estimated Phosphorus Input
Estimated Hydrologic Balances
Agency Responsibilities
Phosphorus Loading and Residence Time
Phosphorus Content After Step Chage in Input Rate
Estimated Evapotranspiration in the Lake Minnetonka Watershed
Average Year Surface Water Balance
Lake Elevations for a Severe Drought Under Year 2000 Conditions
Abbreviations
Volume
Cubic meter = m3
Cubic foot = cf of ft3
Liter = 1
Acre-foot = AF
Flow
Cubic foot per second = cfs
Gallons per minute = gpm
Million gallons per day = mgd
Gallons per capita per day = gpcd
Weight
POWld = lb
Metric ton = MT
Kilogram = kg
Gram = g
Milligram = mg ~
Microgram = ug
Concentration
Gram per cubic meter = g/m3
Milligram per cubic meter = 1119'/1
Milligram per liter = 1119'/1
Microgram per liter = ug/l
Volume
1 .3 = 35.3 ft3
= 1000 1
1 AF = 43,560 ft3
Flow
1 cfs = 448.8 say 450 gpm / = 1.98 AF/day say 2 AF/day
1 mgd = 0.17 inches of water per year on the 123 square miles of the watershed / = 0.98 inches of water per year on the 21.5 square miles of Lake Minnetonka
Weight
2.2 lb = 1 kg
MT = 1,000 kg / = 2,200 lb / = 1.1 short tons
kg = 2.2 lb / = weight of 1 liter of water
g = 1/1000 kg
mg = 1/1,000 g
pg = 1/1,000,000 g
Concentration
g/m3= 1 mg/1 / = 1 part per million for practical purposes
pg/l = 1 mg/m 3 / = 0.001 mg/1 / = 1 part per billion for practical purposes