LIMNOLOGY AND LAKE MANAGEMENT LAKE LEADERS SEPTEMBER 2002

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LIMNOLOGY AND LAKE MANAGEMENTLAKE LEADERS
SEPTEMBER 2002
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Wisconsin Lakes
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The Wisconsin Lakes Partnership

• Wisconsin Association of Lakes
• Lake Organizations and Citizen Networks
• Political Will
• University of Wisconsin Extension
• Organization and Educational Assistance
• Department of Natural Resources
• Technical and Financial Assistance

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WI Department of Natural Resources

• Regional Technical Assistance
• Self - Help Citizen Lake Monitoring
• Lake Planning, Protection and RBF Grants
• Aquatic Plant Management
• Lake Protection and Restoration
• Lake and Watershed Standards
• Water Use and Public Access
• Regulation and Enforcement
• Agency Partnerships

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LAKE TYPES

• Seepage
• Groundwater Drainage
• Drainage
• Impoundments
• Oxbow

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SEEPAGE LAKE

• Natural Lake
• Water Source
• Groundwater
• Precipitation
• No Stream Outlet/ Inlet

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SEEPAGE LAKE

• Round Lake, Chippewa County

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GROUNDWATER DRAINAGE

• Natural Lake
• Water Source
• Groundwater
• Precipitation
• Limited Runoff
• Has Stream Outlet

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GROUNDWATER DRAINAGE LAKE

• Sand Lake, Chippewa County

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DRAINAGE LAKE

• Water Source
• Streams
• Groundwater
• Precipitation
• Runoff
• Stream Drained

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DRAINAGE LAKE

• Long Lake, Chippewa County

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IMPOUNDMENT

• A manmade lake
• Dammed Riveror Stream

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IMPOUNDMENT

• Lake Altoona, Eau Claire County

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OXBOW

• Lake Hallie, Chippewa County

• Half Moon Lake, Chippewa County

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PHYSICAL CHARACTERISTICS

• Mixing / Stratification
• Lake Depth
• Retention Time / Flushing Rate
• Drainage Basin/ Lake Area Ratio
• Influence of Watershed Runoff

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MIXING/ STRATIFICATION
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LAKE DEPTH MATTERS

• Deep Lakes
• Stratify
• Shallow Lakes
• Continuous Nutrient Recycling

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DRAINAGE BASIN/LAKE AREA RATIO

• Seepage Lake- small
• Drainage Lake- large watershed
• Seepage Lake w/ drainage area mapped Round Lake

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RETENTION TIME/FLUSHING RATE

• How long would it take to fill a drained lake?
• Retention Time Matters
• Long Lake Altoona
• Long Lake, 7years
• Lake Altoona, 22days

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CHEMICAL CHARACTERISTICS

• Chemical Characteristics
• Limiting Nutrient Concept P vs N
• Lake 227

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CHEMICAL CHARACTERISTICS

• Nutrients
• P
• N
• pH
• Hardness/ Alkalinity
• Dissolved Oxygen(optimum 5 ppm)

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LIMITING NUTRIENT PRINCIPLE

• That Nutrient in Least SupplyRelative to Plant
  Needs
• NP Ratio in plant Tissue 101 - 151
• If the Ratio of NP in Water is
• lt101 Nitrogen Limited
• gt151 Phosphorus Limited

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PHOSPHORUS LIMITATIONLAKE 227
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TOTAL PHOSPHORUS/ CHLOROPHYLL a RELATIONSHIP

• Phosphoruscauses algaeto grow

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BIOLOGICAL CHARACTERISTICS

• Viruses/ Bacteria/ Fungi
• Primary - Producers Algae/ Macrophyte
• Zooplankton/ Inverts
• Fish

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TROPHIC PYRIMID
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ALGAE

• Primary Energy Sourcefor Invertebrates
• Can be Nuisance
• Produce O2

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AQUATIC PLANTS

• Habitat
• Energy Dissipation
• O2 Producers

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ZOOPLANKTON AQUATIC INVERTEBRATES

• Zooplankton
• Dragonfly

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FISH

• Planktivore
• Piscivore
• Benthivore

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TROPHIC STATE

• Nutrients Productivity
• Sediment Accumulation
• Species Shifts
• Species Richness

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LAKE HABITAT ZONES
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LAKE LITTORAL ZONE

• Functions
• Intercepts Nutrients
• Refuge from Predators
• Nursery for Fish

Oligotrophic Northern Lake
Eutrophic Southern Lake
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ENVIRONMENTAL SIGNS OF DEGRADATION
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LOSS OF WATER CLARITY
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HYPOLIMNETIC DO DEPLETION
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NUISANCE ALGAE BLOOMS
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FISHERIES DEGRADATION
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PALEOLIMNOLGY
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LAND USE AND WATERSHED IMPACTS
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NUTRIENT LOADING
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LAKE AND WATERSHED ASSESSMENT STRATEGY

• RESOURCE ASSESSMENT
• SENSITIVITY ANALYSIS
• ACHIEVEABILITY ANALYSIS
• GOAL SETTING

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RESOURCE ASSESSMENT

• RESOURCE AND WATERSHED MONITORING AND MODELING

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Half Moon Lake - Objectives

• External P sources from storm sewers
• Internal P sources from
• Sediment
• Plant Decomposition
• Motor Boat Activity

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RESOURCE SENSITIVITY ANALYSIS
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Model TypesEmpirical Mechanistic
Input
Input
Output
Output
Statistics
Process Descriptions
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WHERE DO MODELS FIT ?
Linkage between WQ targets and sources
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100
80
60
CHLA, ug/L
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20
0
Baseline
Storm
Motor
Plant
Sediment
Sediment
Internal
Internal
Sewer
Boat
Control
Control
Plant
Load
Storm
Control
Control
Control
Control
Sewer
Load
Control
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ACHIEVEABILITYANALYSIS
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Nutrient Reduction Strategies

• Alum
• Aquatic Plant Management
• Lake Use Controls
• Storm Water Management

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RESOURCE GOAL SETTING
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LEAVING A LEGACY

• Help Protect Wisconsins
• WATER RESOURCES.