Rick Gerber WHPA presentation - CTC Source Protection Region · CTC SWP - Municipal Pumping Rates 0 500 1,000 1,500 2,000 2,500 3,000 3,500 4,000 4,500 1A Ce d a e W ll 3 Ce d a r

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CTC Source Protection RegionCTC Source Protection Regionwww.ctcswp.ca

Made possible through the support of the Government of Ontario

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Groundwater Quality Vulnerability Analysis- WHPA delineation & vulnerability

CTC SWP Committee October 20, 2009 Rick Gerber

CTC Source Protection RegionCTC Source Protection Region

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1) Technical Rules/Technical Bulletins> November 20, 2008

2) WHPA & Vulnerability DelineationVelocity/travel times

3) Peel Region (TRCA) WHPAsEarthfx Inc (October 17, 2007)AMEC Peer Review (August 21, 2009)

4) Conclusions/Discussion

OverviewOverview

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Made possible through the support of the Government of OntarioSlide modified from MOE 24-Mar-2009

1. Technical Rules/Bulletins (Nov, 2008)1. Technical Rules/Bulletins (Nov, 2008)Groundwater Quality Vulnerability Analysis – WHPA

• Assess the intrinsic vulnerability according to the natural susceptibility of aquifers to becoming contaminated1) Delineate Wellhead Protection Area (WHPA-A,B,C,D; Part VPart V);2) Determine natural vulnerability of aquifer system to contaminants (H,M,L

– Part IVPart IV);3) Overlay 1 & 2 to determine vulnerability scores (Part VII.3Part VII.3).

Consider anthropogenic transport pathways (Part IVPart IV)Assess uncertainty with plans for continuous improvement (Part I.4Part I.4)

• Threats and Issues mapping within WHPA (Vulnerability score of 6) (Part XIPart XI)• Risk Score = Hazard Rating (1-10) x Vulnerability Score (6) (Part XIPart XI)

Vulnerability score <=6 cannot contain a significant threat(Significant > 80; Moderate 60-79; Low 40-59)

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Made possible through the support of the Government of OntarioSlide from MOE 24-Mar-2009

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4

2

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2. WHPA & Vulnerability Delineation2. WHPA & Vulnerability Delineation• v = Ki/n = average linear velocity; where

K = hydraulic conductivity (constant of proportionality describing ease with which a fluid can move through a porous media)

i = hydraulic gradient

n = porosity

From Freeze & Cherry (1979)Average linear groundwater flow velocity

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Made possible through the support of the Government of OntarioFrom Freeze & Cherry (1979)

Note range

Higher K =Higher average linear groundwater flow velocity

K=hydraulic conductivityv = Ki/n

Hydraulic conductivity

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From Freeze & Cherry (1979)

i=hydraulic gradient; higher i = higher avg linear gw flow velocityv = Ki/n

Hydraulic gradient

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Made possible through the support of the Government of Ontario porosity

From Freeze & Cherry (1979) From Freeze & Cherry (1979)

(<1%)

~30% ~15% >50%n=porosity;

higher n = lower avg linear velocityv = Ki/n

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Good Aquifer: v=Ki/n=(1e-4 m/s)*0.01/0.3 = 105 m/yr (avg linear flow velocity)note - fracture flow can be much higher (m/d)

Average linear groundwater flow velocity

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Contaminant Transport• Contaminants can move at the average linear

groundater flow velocity (e.g chloride) OR• Movement can be slower (e.g. sorption,

dispersion, diffusion according to concentration gradients, etc);

• Decrease mass but not necessarily velocity (e.g. dilution, radioactive decay, biodegradation, chemical reactions, ion-exchange, etc); and

• Increase velocity (colloidal transport, complexation, etc)

Contaminants interact w physical, chemical & biological system

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Groundwater Vulnerability (WHPA)a) Delineate Vulnerable Area – WHPA (A,B,C, C1-10yr and D)b) Assign intrinsic vulnerability

0-5yrs High, 5-25yrs Medium, >25yrs Low Relative Intrinsic Vulnerabilityc) Overlay WHPA zones with Intrinsic Vulnerability to give Vulnerability Scored) Constructed pathwayse) Uncertainty

Unsaturated till

Saturated till

Saturated aquifer

WAA

T

SAAT

UZA

T

JHL

½ W

AAT

SWAT

WW

AT2 year TOT

(WHPA: A=100m; B=2yrC=5yr and D = 25 yr)

d) Numerical GW Flow Modelling – WAAT/SAAT

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CTC SWP - Municipal Pumping Rates

0

500

1,000

1,500

2,000

2,500

3,000

3,500

4,000

4,500

Cedar

vale

Well

1A

Cedar

vale

Well

3

Cedar

vale

Well

4A

Prince

ss A

nn W

ell 6

Linds

ay C

ourt

Well

4th Li

ne W

ell A

Davids

on W

ell 2

Prosp

ect P

ark W

ellErin

Well

7

Erin W

ell 8

Hillsbu

rgh W

ell H

2

Hillsbu

rgh W

ell H

3

Orange

ville

5-5A

Orang

eville

6

Orang

eville

7 - P

assm

ore

Orange

ville

8A

Orange

ville

8B

Orange

ville

8C

Orang

eville

9A-9

B

Orang

eville

10

Orang

eville

11

Cardin

al W

oods

Well

1

Cardin

al W

oods

Well

3

Coles W

ell 1

Islan

d Lak

e Well

2

Obser

vatio

n Well

2AAlto

n #3

Caledo

n #3

Caledo

n #4

Inglew

ood #

2

Inglew

ood #

3

Chelte

nham

#1

Chelte

nham

#2

Caledo

n Eas

t #2

Caledo

n Eas

t #3

Caledo

n Eas

t #4

Palgra

ve #2

Palgra

ve #3

Palgra

ve #4

Noblet

on #2

Noblet

on #3

Kleinb

urg #

2

Kleinb

urg #

3

King C

ity #3

King C

ity #4

Stouffv

ille #1

Stouffv

ille #2

Stouffv

ille #3

Stouffv

ille #5

Stouffv

ille #6

Uxville

pum

ping

rate

(m3/

d)

Lyndsay Court

Orangeville 5-5A Palgrave 4

Stouffville 3,5

Cedarvale 4A

Caledon East 4

Palgrave 3

~0.4 m3

2005/2006 municipal pumping rates

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Recharge = 15 mm/yr Q = 0, -1000, etc m3/d (x=y=5000m)50m Kh/Kv(m/s) Ss (1/m)/Sy n

upper aquifer-a 40m 10-4/10-5 1e-4/0.30 0.3 CH=50m

upper-aquifer-b CH=41m 10-4/10-5 1e-4/0.30 0.3 CH=50m

30m lower aquitard

10m 10-8/10-9 1e-6/0.10 0.1lower aquifer

CH=25m 10-4/10-5 1e-4/0.30 0.3 CH=45m0m

y=10,000 m

Numerical GW Flow Modelling – estimate travel times

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Lower aquifer;Q=1000 m3/d;25yr TOT

Q=1000 m3/dLower aquifer - steady state particle traces

Q=2000 m3/d

Upper aquifer;Q=1000 m3/d;25yr TOTLower aquiferQ=2000 m3/d; 25yr TOT

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Upper aquifer; Q1000 m3/d; steady state particles

Lower aquifer; Q1000 m3/d; steady state particles

Lower aquifer; Q2000 m3/d; steady state particles

Lower aquifer; Q1000 m3/d; 25yr TOT

Lower aquifer; Q2000 m3/d; 25yr TOT

No pumping

~450 m/25 yr

~1250 m/25 yr

~1550 m/25 yr

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Made possible through the support of the Government of Ontario Municipal Supply Wells & Intakes

WellingtonCounty

Lorne Park

LakeviewR.L. Clark

Toronto Island

R.C. Harris

Lakeview

F.J. Horgan

Whitby

3. Peel Region (TRCA) WHPAs

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Made possible through the support of the Government of Ontario Surficial Geology (OGS) & Recharge

EastCross Section

WestCross Section

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Peel

–W

ellin

gton

Bou

ndar

y

Alto

n

Airp

ort R

oad

Hea

rt L

ake

Rd.

Peel

–Yo

rkB

ound

ary

(Hw

y #9

)

Palg

rave

Section LocationM

ount

Wol

fe R

oad

(Figure from Earthfx)

Hydraulic Setting #2 – ~ West Half

shallow aquiferORM

deep aquifer (TF)

deep aquifer (Sc)

Bedrock(shale)

Bedrock(aquifer)

W E

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Made possible through the support of the Government of Ontario(Figure from Earthfx, October 17, 2007)

Observed groundwater levelsOak Ridges Aquifer Complex

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West Model extent

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a) WHPA from Time of Travel

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b) Natural intrinsic susceptibility

ISI (Intrinsic Susceptibility Index) = thickness x K-factor(sum for each unit above aquifer)

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Palgrave 2: 47m deep(permeable ORAC, shallow water table)

Palgrave 3: 82 m deep(deeper water table, more silt in ORAC)


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CE4: 55mTAC

CE3: 19mORAC- Cl

CE2: 30mORAC(GUDI)- Cl

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Note: only zones >6 canHave significant threat(Water Quality Risk Assessment)- Constructed pathways? (private wells, pits/quarries, etc)

c) Vulnerability scoring

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4. Conclusion/Future Tasks4. Conclusion/Future Tasks• Vulnerability (travel times) can be tested

• Chemistry, isotopes, pumping tests, etc• Sentry wells

• Confirm information & complete mapping• Consistency with HVA vulnerability• Anthropogenic constructed pathways• Uncertainty

• Peer Review

• Threats Inventory & Risk Assessment

Documents

Rick Gerber WHPA presentation - CTC Source Protection Region · CTC SWP - Municipal Pumping Rates 0 500 1,000 1,500 2,000 2,500 3,000 3,500 4,000 4,500 1A Ce d a e W ll 3 Ce d a r