Source Water Protection Workshop Apr 18- 19
Intake Protection Zones (IPZs) in the Great Lakes: Scientific, Environmental Engineering, & Practical Considerations for Protecting Sources of Drinking Water.
William J Snodgrass, P.Eng., PhD. Water Infrastructure Management City of Toronto
wsnodgr @ toronto.ca THE CITY OF TORONTO
• Provides drinking water, wastewater and stormwater management services to 2.5 million residents
• Provides drinking water to 400,000 residents in York Region
• Expected population growth of 1/2 million people in 25 years TORONTO’S PRIORITIES
• Continue to provide safe, clean and reliable drinking water to residents and businesses
• Renew aging infrastructure (40% of city’s watermains are older than 50 years, which results in a backlog of infrastructure renewal)
• Provide capacity for population growth
• Meet legislative and regulatory requirements
• Be stewards of the environment THE GREAT LAKES BASIN CONTEXT FOR SOURCE WATER PROTECTION
• Great Lakes source for 75% of Ontario’s population
• 95 municipal water systems rely on Great Lakes source water Lake Ontario Bathymetry: 3-D YPDT Groundwater Management Study (Mr Holysh) SOURCE WATER THREATS: IMPACTS OF URBANIZATION • Source Water •Nearshore Zone •Watersheds diluted with mainlake water • Protecting all intake pipes along the Great Lakes is important • Near-shore intake pipes
Urban are 0.5 - 5 kilometres long Rural • Expanding urbanization is a dominant threat • An estimated population growth of 20% in five years ENVIRONMENTAL IMPACTS (as identified by RAP- Remedial Action Plan)
• Contamination of recreational beach areas
• Impacts on fisheries and aquatic biota
• Sediment quality and benthic invertebrates
• Contributing to fish consumption advisories
• Loss of fish habitat
• Nutrient enrichment: nuisance algal growth TORONTO’S WET WEATHER FLOW MASTER PLAN Is the foundation of our SOURCE WATER PROTECTION PLANNING
PRESENTATION OUTLINE
1) Scientific & Environmental Engineering Methodology Of The WWFMP
2) Need to Develop a Great Lakes Source Protection Plan
3) Practical Considerations in delineating Intake Protection Zones in the Great Lakes
4) What Role may Source Water Protection Play for City of Toronto in delivering Potable Water Supply 4. SOURCE WATER CONTROL PERPSECTIVE: Risk of Pathogens in Diffuse Sources to Intakes • Perspective - Follow Environmental Pathways from Source to ‘Tap’ Water - How much risk reduction occurs at each step in the pathway - For example, can Source Water Protection Planning provide 2 orders of magnitude reduction in risk for E Coli • Estimated E Coli Densities (number per 100 ml) - CSO - 1.2 million - Stormwater – Urban – 400,000 - Suburban (905) 100,000 - River mouths 1,000 – 50,000 - Treatment (CSO, stormwaater, WWTP) - 1000 - Objectives -Non Contact recreation 500 -Beach Posting – 100 -Drinking Water – N D (< 1 )
-Risk Assessment (< 0.0 xxx1 ? ) 1. SCIENTIFIC & ENVIRONMENTAL ENGINEERING METHODOLOGY TORONTO’S WET WEATHER FLOW MASTER PLAN
1) Set up land parcels, define soils, land cover [eg. impervious, vegetation]
2) Route Flow according to network
3) Calibrate Flow for each watershed
4) Calibrate Quality for each watershed
5) Run model to calculate loadings and provide time series (flow and concentrations) at waterfront LINKING LOT to WATERSHED
ADJALA- MONO TOSORONTIO RICHMOND HILL KING
CALEDON
Region Region of of Watershed N Peel York
VAUGHAN
BRAMPTON
CITY OF Study Area Sub-Watersheds Watercourses TORONTO
Regional Boundaries
Municipal Boundaries
Combined Sewer Area
Seperate Sewer Area
Sewershed Sub-Watersheds Humber River Main Stem West Branch Humber River Albion Creek Black Creek Berry Creek Emery Creek Humber Creek Silver Creek Combined Sewer Area Residential Lot CITY OF TORONTO - SEWER OUTFALL LOCATIONS COMBINED SEWER SERVICE AREA WATERSHED COMPONENT ANALYSIS
Approach:
1) Assess existing impact
2) Project future impact through continued urbanization
3) Assess effectiveness of various non-point source control options: - source controls - conveyance - end-of-pipe
FISRWG, 1998 CONTAMINANT CHARACTERISTICS
1000 stormwater CSO E. Coli 10000000 PWQO 100
d) 1000000 e t se no se i 10 100000 erw ) th ess o l 10000 1 un (
/L 1000 E. Coli (counts/dL Coli E. on, mg on, ti 0.1 ra t 100 concen 0.01 10
0.001 1 COMPARISON OF STORMWATER AND CSO DATA HSPF - REPRESENTATIVE RUNOFF CALIBRATION: MIMICO CREEK (1991 – 1994)
Flow Rate (dam3/day) 1 0.3 0.6 1 2 2.7 4 8 15 30 70 100 120
0.1
0.01 Predicted Observed
0.001 Fraction of Time Greater Than Fraction of Time Greater HSPF Calibration by Watershed: E. Coli
Comparison of Water Quality by Watershed Ecoli 100000 RAP Avg WET RAP WET LL RAP WET UL RAP Avg DRY RAP DRY LL RAP DRY UL Modelled WET Modelled DRY PWQMN Avg WET PWQMN Avg DRY 10000 Concentration (#/dL) 1000
100 Etobicoke Mimico Humber Don Highland Rouge Watershed ControlsControls ExaminedExamined (Dr Bradford)
1) Source (private property)
2) Conveyance (ditches, pipes, ie, network )
3) End – of pipe
4) Operations & Maintenance
5) Dry – weather
6) Reforestation
7) Pollution Prevention
8) Education LAKE WIDE CIRCULATION MODEL SETUP: Bathymetry [3564 m grid; 10 -30 layers as fn of application ]
Adjusted bathymetry
43 40 ° 3 0' N
35
4 3° 15 30 ' N
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43 ° 0 ' N 20 Palette Abov e 0 -15 - 0 (Grid spacing 3564meter) spacing (Grid 15 -30 - -15 42 N ° 4 -45 - -30 5' N -60 - -45 -75 - -60 -90 - -75 10 -105 - -90 -120 - -105 -135 - -120 -150 - -135 4 -165 - -150 5 2° 3 -180 - -165 0' N W W W W W W W W W W ' ' ' W ' ' ' ' ' ' -195 - -180 ' 5 0 5 ' 5 0 5 ' W 5 0 5 -210 - -195 0 4 3 1 4 3 1 0 4 3 1 ° ° ° ° ° 0 ° ° ° ° ° ° ° 9 8 8 8 7 7 7 7 6 6 6 Below -210 7 78 7 7 7 7 7 7 7 7 7
0 7 Undef ined Value 0 5 10 15 20 25 30 35 40 45 50 55 60 65 70 75 (Grid spacing 3564 meter) 01/01/90 00:00:00, Time step: 0, Layer: 0 0 - 5 -5 - 0 -10 - -5 -15 - -10 -20 - -15 -25 - -20 -30 - -25 -35 - -30 -40 - -35 -45 - -40 -50 - -45 -55 - -50 -60 - -55 -65 - -60 Abov e 5 -65 Below Undef ined Value Palette
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Bathymetry [
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TORONTO WATERFRONT SETUP: TORONTO WATERFRONT SETUP:
W
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01/01/90 00:00:00, Time step: 0, Layer: 0 Layer: 0, Time 00:00:00, 01/01/90 step: 0
0 40 30 20 10 (Grid spacing 132 meter) 132 spacing (Grid TEMPERATURE CALIBRATION: 1991 R.C.Harris WTP Data LAKE CURRENT CALIBRATION: 2001 ADCP DATA
0.5 Model Calibration
0.4
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1 15 29 43 57 71 85 99 113 127 141 155 169 183 197 211 225 239 253 267 281 295 0 Speed (m/s) Speed
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-0.2 Sept 21 to Oct 2 -0.3
Model U Model V RCM U RCM V TORONTO WATERFRONT MODELLING PREDICTIONS: E. Coli [portion of time greater than 100 /100ml]
2. DEVELOPMENT OF A GREAT LAKES SOURCE PROTECTION PLAN
• Western Lake Ontario Consortia – a potential model
• A municipal partnership, funded by the province
• A consortia of municipalities around the “Golden Horseshoe”, supported by all Conservation Authorities, the Provincial and Federal Government agencies
• Objectives: - consolidate pollution source data across basin - develop a common approach to assess threats to water intakes - develop a common approach to mitigate impacts and risks - develop a platform to regularly update and maintain source data DEVELOPMENT OF A GREAT LAKES BASIN SOURCE PROTECTION PLAN
• Considerations:
- Develop Basin Specific Bi-national Great Lakes Source Protection Plans
- Establish Basin Specific SPCs led by MOE and Environment Canada
- Include affected CAs and municipalities
- Develop & maintain a common framework to assess ongoing and future threats and to mitigates impacts
- Pollution Prevention/Mitigation Focus 3.3. PracticalPractical ConsiderationsConsiderations Lake Ontario Bathymetry: 3-D WATERSHEDS EFFECTING NEARSHORE ZONE OF LAKE ONTARIO
Major Watersheds along north shore of Lake Ontario: • Moira, Trent
• Kawarthas
• Humber, Don, Rouge
• Credit, Bronte
• Welland, Niagara AUGMENT MOE GUIDANCE APPROACH (current focus – acute, an event)
• DESK TOP EXERCISE: One zone off-shore Two-zones off-shore
- Conduct a 1D analysis to delineate IPZ2
- Time of travel is arbitrary Two zones near-shore
- Do we use 2 hr or 24 hr?
- Applicable to river based uni-directional sytems: NOT applicable to Great Lakes! EFFECTS OF WET WEATHER FLOW ON NEARSHORE ZONE OF LAKE ONTARIO
• Humber River Plume: 0.7 km X 6 km
• Note Humber WWTP Plume
• Issues: - Tributaries and WWTP dictate limits of IPZ2 - Is IPZ2: 2 km, 6-7 km, or 30 km along nearshore? Whitby Ajax Major PollutionIntakes Sources and Duffins creek Corbett and Harmony Water Treatment Plant Intakes Duffin creek In the Lake Ontario Consortia Highland creek
RC Harris, FJ Horgan Don river Toronto Ashbridges Bay Humber river RL Clark Humber Lakeview
Lakeview
Credit river Clarkson
16 Mile creek Oakville Oakville Mid Halton Oakville southwest Burlington
Niagara-on-the lake Skyway Burlington ship canal Hamilton PortWeller Biggar lagoon Niagara River Baker Road Port Dalhousie Welland Ship canal Hamilton Twelve Mile creek Grimsby Illustration of Need to Augment Guidance Approach beyond acute: Toronto Waterfront - chronic
• Watersheds & Lake Model Results
• Sources Considered: •WWTP discharges •Tributaries •Waterfront storm/CSO
• Isopleths in Graph • WWTP Sources Only • Order of Magnitude intervals • Grid 6 km off-shore of land
• Implications •Need both lake model & watershed loadings to represent risk for chronic concerns • All sources CITY OF TORONTO - SEWER OUTFALL LOCATIONS Do we Investigate every outfall within a 2 hr or 24 hour time of travel of intake? 4. SOURCE WATER CONTROL PERPSECTIVE: Risk of E Coli between Diffuse Sources & Intakes • Estimated E Coli Densities (number per 100 ml) - CSO - 1.2 million - Stormwater – Urban – 400,000 - Suburban (905) 100,000 -Treatment (CSO, stormwater, WWTP) - 1000 - Drinking Water Objectives – N D (< 1 )
-Risk Assessment (< 0.0 xxx1 ? ) • Perspective - Can Source Water Protection Planning provide 2 orders of magnitude reduction in risk for E Coli - In 25 Years, CSO’s controlled – cost $ 1 billion - In 100 Years, Stormwater controlled – cost 12 – 16 billion - 50 % increase in asset value of Water infrastructure (all pipes and treatment plants) • Conclusion - More economical to address risk reduction through treatment technologies Source Water Protection Workshop Apr 18- 19
Intake Protection Zones (IPZs) in the Great Lakes: Scientific, Environmental Engineering, & Practical Considerations for Protecting Sources of Drinking Water.
William J Snodgrass, P.Eng., PhD. Water Infrastructure Management City of Toronto
wsnodgr @ toronto.ca 0.400 HSPF Calibration by Watershed: Total Phosphorus
0.350
Comparison of Water Quality by Watershed Total Phosphorus RAP Avg WET 0.300 RAP WET LL RAP WET UL RAP Avg DRY RAP DRY LL RAP DRY UL 0.250 Modelled WET Modelled DRY PWQMN Avg WET PWQMN Avg DRY 0.200
0.150 Concentration (mg/L)
0.100 Etobicoke Mimico Humber Don Highland Rouge Watershed
0.050
0.000 0 - 8 -8 - 0 -16 - -16 -8 - -24 -16 - -32 -24 - -40 -32 - -48 -40 - -56 -48 - -64 -56 - -72 -64 - -80 -72 - -88 -80 - -96 -88 -104 - -104 -96 Abov e 8 -104 Below Undef Value ined Palette
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1188 m grid] 1188 m grid]
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Adjusted bathymetry 8
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UP: Bathymetry [ 9 UP: Bathymetry [ 7
- - 20
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NEARSHORE SET NEARSHORE SET 5
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01/01/90 00:00:00, Time step: 0, Layer: 0 Layer: 0, Time 00:00:00, step: 01/01/90
8 6 4 2 0 14 12 10 (Grid spacing 1188 meter) 1188 spacing (Grid TORONTO WWFMMP 25 YEAR RESULTS Total Phosphorus [fraction of time >20 ug/L] OVERVIEW OF A PROPOSED APPROACH
• Lake Ontario Hydrodynamic & Water Quality Model - build on work completed in Toronto
• Compile basic municipal & tributary data needed - already agreed to by Steering Committee (ie. at each partner’s expense)
• Basic data needed for this effort • Lake–wide morphology: already incorporated in TO’s work • Lake calibration: – expand TO’s effort: other MOE and EC data available • Inputs: • WTP influents • WWTP discharges • Watersheds – gauged (assign EMC to dry / wet or Bowen’s info) • Watersheds - ungauged • Direct Storms & CSO’s LAKE MODEL CONTINUOUS SIMULATION EXAMPLE: (E. Coli during large wet weather event: August 1991) Toronto’s Experience with Lake Ontario Modelling
• Toronto has run 3 lake hydrodynamic models to date (since early 1980s): - Princeton Oceanic Model - 2D RAND - McMaster – IDOR 3D - DHI - Mike 3D
• Approach used with DHI - Mike 3D:
- Calibrate Flow with current meters
- Calibrate Vertical Stratification with field measurements and WTP intake data
- Calibrate Quality with field measurements: MOE/EC lake stations, beach water quality and WTP intakes
- Run model to predict lake and nearshore water quality response WET WEATHER FLOW STRATEGY DEVELOPMENT
Strategy Strategy Name Target Level Source Conveyance Operations End of Pipe Dry Weather No. Controls Controls & Flow Maintenance Status Quo Existing As As required Existing Existing Existing 1 required on-site for on-site for infill infill Opportunistic Not specific Voluntary Time limited Existing Opportunistic, Limited 2 BMP exfiltration & green improvement filtration infrastructure (based on search & destroy program)
Moderate Moderate Voluntary Time limited Existing Opportunistic Limited 3 Targets- EOP Enhancement exfiltration & & aggressive improvement Oriented filtration facilities Moderate Moderate Enhanced Enhanced Enhanced Opportunistic, Extensive 4 Targets – Enhancement exfiltration & green improvement Source filtration (not infrastructure (based on Oriented time limited) long term infrastructure replacement) Significant Significant Enhanced Enhanced Enhanced Opportunistic Extensive 5 Targets Enhancement & aggressive improvement facilities Evaluated Several sets of Watershed Control Options - - Five final Strategies Evaluated and their Cost Estimates
Strat Description Cost No. [billion]
1 Status Quo accom., upstream growth and intensification in 1 + Toronto (1 million)
2 Opportunistic 3
3 Achieve moderate targets with aggressive 5 E O P
4 Achieve moderate targets – aggressive source and conveyance 6 controls
5 Achieve significant targets 11 INADEQUACY OF MOE GUIDANCE RE 1 – D
• REALITY OF NEARSHORE ZONE •Frequency distribution of velocity vectors •Example on slide- waves inside complex land form •Velocity rose •More from opposite directions that wave rose
• PROPOSED APPROACH WOULD •Address Frequency distribution issue •ETC TORONTO’S WET WEATHER FLOW MASTER PLAN: Overview of Modelling approach • Pollutant Sources - 4 wastewater treatment plants (3 largest directly to Lake Ontario) - 79 combined sewer overflow outfalls (33 directly to Lake Ontario) - 600 storm sewer outfalls (70 directly to Lake Ontario) - 6 watersheds (all but one extend beyond City limits: agricultural and urban runoff contributions)
• Hydrology, Hydraulic & Water Quality Modelling - Watershed Based Approach for Separated Sewer Areas: US EPA - HSPF - Runoff Quantity & Quality - Instream Impacts - Combined Sewer Area Modelled Separately: Dorsch - QQS - Lakefront Hydrodynamic and Water Quality Simulation Model: DHI - MIKE 3D TEMPERATURE CALIBRATION: 1993 R.C.Harris WTP Data MOE’S LAKE CURRENT METER LOCATIONS (1993) Lake Ontario Source Water Protection Consortia Requirements
• Lake model
• Watershed based modelling: - some available - NWRI support
• WWTP discharges: available
• Direct sewer discharges: - some available - extrapolate from available
• Data for calibration of Lake Model: - some available: EC, MOE, CAs
• Model calibration
• Calculate IPZs