Sept. 10 and 11, 2007 Lake Tahoe TMDL - Phase Two 1
Lake Tahoe TMDLLake Tahoe TMDLPhase TwoPhase Two
Fall 2007 Public Participation Series
Source Category Group Focus Team Meetings
Sept. 10 and 11, 2007 Lake Tahoe TMDL - Phase Two 2
TMDL Program Overview
A science-based plan to restore
Lake Tahoe’s clarity
Sept. 10 and 11, 2007 Lake Tahoe TMDL - Phase Two 3
Central TMDL QuestionsQuestions Addressed1. What pollutants are causing Lake Tahoe’s clarity loss?
2. How much of each pollutant is reaching Lake Tahoe?
3. How much of each pollutant can Lake Tahoe accept and still achieve the clarity goal?
Current Questions1. What are the options for reducing pollutant inputs to Lake
Tahoe?
2. What strategy should we implement to reduce pollutant inputs to Lake Tahoe?
Sept. 10 and 11, 2007 Lake Tahoe TMDL - Phase Two 4
Source Category Group AnalysisOpportunities
• Basin-Wide load reduction estimates
• Relative load reduction opportunity among source categories
• Consistent methods to evaluate future pollutant control options
Sept. 10 and 11, 2007 Lake Tahoe TMDL - Phase Two 5
Source Category Group Analysis Boundaries
• Not suited to project scale
• Evaluated pollutant control options chosen for data availability
• Limited time, resources, and effectiveness data
Sept. 10 and 11, 2007 Lake Tahoe TMDL - Phase Two 6
Continuous Improvement
• Adaptive management process
• SNPLMA science funding opportunities
• Each group identified “next steps” and data needs
Sept. 10 and 11, 2007 Lake Tahoe TMDL - Phase Two 7
Focus Team Role
• Gain technical understanding of SCG approach
• Act as a liaison to your agency
• Provide input on preferred pollutant control options
• Suggestions for future work
Sept. 10 and 11, 2007 Lake Tahoe TMDL - Phase Two 8
Questions?
Sept. 10 and 11, 2007 Lake Tahoe TMDL - Phase Two 9
Questions Addressed
What is causing Lake Tahoe’s clarity loss?
• Suspended fine sediment
• Floating algae – fed by nutrients
• Very fine sediment (<20 microns) accounts for ~2/3 of the clarity conditions
Sept. 10 and 11, 2007 Lake Tahoe TMDL - Phase Two 10
How much of each pollutant is reaching Lake Tahoe?
Total Nitrogen Estimates: Percent Contribution per Source Category
Shoreline Erosion 0.5%
Stream Channel
Erosion 0.5%
Urban Upland 16%
Non-urban Upland 15.5%
Atmospheric Deposition
55%
Groundwater 12.5%
Sept. 10 and 11, 2007 Lake Tahoe TMDL - Phase Two 11
How much of each pollutant is reaching Lake Tahoe?
Fine Sediment Particle Number Estimates(particles less than 20 micrometers):
Percent Contribution per Source Category
Atmospheric Deposition
15%
Non-urban Upland
9%
Urban Upland 72%
Stream Channel Erosion
4% Shoreline Erosion < 1%
Sept. 10 and 11, 2007 Lake Tahoe TMDL - Phase Two 12
How much of each pollutant is reaching Lake Tahoe?
Total Phosphorus Estimates: Percent Contribution per Source Category
Non-urban Upland 26%
Stream Channel
Erosion 2%
Atmospheric Deposition
15%
Groundwater 15%
Shoreline Erosion 4% Urban Upland
38%
Sept. 10 and 11, 2007 Lake Tahoe TMDL - Phase Two 13
How much of each pollutant can Lake Tahoe accept and still achieve the clarity
goal?
• The Lake Clarity Model provides estimates of clarity response to load reductions
• Reducing fines has a greater potential to improve clarity
• Model output indicates significant reductions will be needed
Sept. 10 and 11, 2007 Lake Tahoe TMDL - Phase Two 14
What are the options for reducing pollutant inputs to Lake Tahoe?
Good Question!Good Question!
Sept. 10 and 11, 2007 Lake Tahoe TMDL - Phase Two 15
Approach to Answering Current Questions
• Identify load reduction options
• Quantify load reduction options
• Prepare Integrated Strategies
• Gather stakeholder input
Sept. 10 and 11, 2007 Lake Tahoe TMDL - Phase Two 16
Pollutant Load Reduction Opportunity Project - People
• Source Category Groups
• Technical Reviewers
• Source Category Integration Committee
• Project Team
• Focus Teams
PCO Concepts
Screening Process
Viable PCOs
PCO Grouping Process
TreatmentTiers
A
A
BC
A
BC
Settings
Extrapolation Process•GIS•Models
Step 1: PCO Evaluation Step 2: Site-Scale Analysis
Step 3: Basin-Wide Analysis
Nitrogen Reduction
Table
Sediment Reduction
Table
Phosphorus Reduction
Table
Tier 1
Tier 2
Tier 3
Load Tables
CostTables
Co
mb
ine
d R
es
ult
s
Ta
ble
s
Total 20 Year Cost Table
Capital Cost Table
O & M Cost Table
Cost-Effectiveness
Table
PCO Concepts
Screening Process
PCO Concepts
Screening Process
Viable PCOs
PCO Grouping Process
TreatmentTiers
A
A
BC
A
BC
Settings
Extrapolation Process•GIS•Models
Step 1: PCO Evaluation Step 2: Site-Scale Analysis
Step 3: Basin-Wide Analysis
Nitrogen Reduction
Table
Sediment Reduction
Table
Phosphorus Reduction
Table
Tier 1
Tier 2
Tier 3
Load Tables
CostTables
Co
mb
ine
d R
es
ult
s
Ta
ble
s
Total 20 Year Cost Table
Capital Cost Table
O & M Cost Table
Cost-Effectiveness
Table
PCO Concepts
Screening Process
PCO Concepts
Screening Process
Viable PCOs
PCO Grouping Process
TreatmentTiers
A
A
BC
A
BC
Settings
Extrapolation Process•GIS•Models
Step 1: PCO Evaluation Step 2: Site-Scale Analysis
Step 3: Basin-Wide Analysis
Nitrogen Reduction
Table
Sediment Reduction
Table
Phosphorus Reduction
Table
Tier 1
Tier 2
Tier 3
Load Tables
CostTables
Co
mb
ine
d R
es
ult
s
Ta
ble
s
Total 20 Year Cost Table
Capital Cost Table
O & M Cost Table
Cost-Effectiveness
Table
PCO Concepts
Screening Process
Sept. 10 and 11, 2007 Lake Tahoe TMDL - Phase Two 20
Development Summary
• PCO Selection and Evaluation
• Site Scale Analysis– Settings– Tiers
• Basin-wide extrapolation