CTC Source Protection Region
www.ctcswp.ca
CTC Source Protection Region
Tier 1 Water Budget CTC SPC Meeting # 2/09 – Agenda Item # 6.1 February 17, 2009 Gayle SooChan, P.Geo. Director, Groundwater Resources, CLOCA Dirk Kassenaar, M.Sc. P.Eng E.J. Wexler, M.Sc., M.Sc. (Eng)
1 Made possible through the support of the Government of Ontario CTC Source Protection Region
www.ctcswp.ca CLOSPA Tier 1 Water Budget Process/ Timelines
• Earthfx Inc. – Prepared the T1 Water Budget Study for the CLOCA jurisdiction – draft completed Jan 08 • Peer Review process initiated Feb 08 • Revised per comments and re-circulated to Peer reviewers for sign-off Aug 08 • Additional comments received from municipality Oct 08 • Revised per final comments, distributed to SPC Feb 09 for acceptance • Formal Peer Review Team : Durham Region (Works Dept.), Papadoupolos & Associates, Dr. R. Gerber, TCC Source Protection Region, Ministry of Natural Resources, Conservation Ontario. • MOE-CR and LSGB Source Protection Region were also invited to comment and provided material. No comments were however received.
Made possible through the support of the Government of Ontario CTC Source Protection Region
www.ctcswp.ca Peer Review Comments: on Draft Tier 1 • In our opinion, this is an excellent report that provides a solid framework for those charged with managing water-resources in the CLOCA area. • The analyses have been conducted to a high technical standard. • Peer Reviewers main suggestions for revisions were associated with some unique methodologies in determination of the groundwater supply factor which affected the stress calculations. The study team was directed to revise the document to ensure provincial consistency in results. • Revisions/corrections were also made to the PTTW data used by the review team. These corrections resulted in revised stress calculations. • Revisions were also made to ensure compliance with the Directors Rules (changes since the historical technical guidance).
Made possible through the support of the Government of Ontario CTC Source Protection Region
www.ctcswp.ca CLOSPA Tier 1 Water Budget Presentation
• Earthfx Inc.: • Dirk Kassenaar, M.Sc. P.Eng • E.J. Wexler, M.Sc., M.Sc. (Eng)
Made possible through the support of the Government of Ontario CTC Source Protection Region
www.ctcswp.ca
CTC Source Protection Region
Draft Accepted Tier 1 Water Budget for the Central Lake Ontario Source Protection Area
Meeting Presentation – February 17, 2009
Dirk Kassenaar, M.Sc., P.Eng. EJ Wexler, M.Sc. M.E. P.Eng. Earthfx Inc. 5 Made possible through the support of the Government of Ontario CTC Source Protection Region
www.ctcswp.ca
Presentation Outline
• Tier 1 Water Budget Objectives • Overview of Selected Approach • Subwatershed assessment areas • Modelling approach • CLOCA Watersheds: Overview • Summary of Tier 1 Water Budget Components • Water Demand, Supply, Reserve • Stress Assessment Results • SGRA Analysis • Conclusions
Made possible through the support of the Government of Ontario CTC Source Protection Region
www.ctcswp.ca
Tier 1 Water Budget: Objectives and Steps
• A Tier 1 water budget is a screening level assessment of water supply and water demand in the study area • Identify subwatersheds needing a more detailed assessment • Calculate “% Water demand” = Water Demand/Supply • Calculated on annual and monthly basis for both groundwater and surface water • Assign a low, moderate or significant “stress” level based on thresholds • Think Low, Medium or High “Relative Demand Level” • Thresholds are conservative and meant only for screening • A Tier 2 is a more detailed and complex assessment to confirm the stress levels, • A Tier 3 is needed to actually assess sustainability, risk and ecological stress • Additional analysis included in this study: • SGRA – Significant Groundwater Recharge Areas
Made possible through the support of the Government of Ontario CTC Source Protection Region
www.ctcswp.ca
Water Budget Components
Made possible through the support of the Government of Ontario CTC Source Protection Region
www.ctcswp.ca
Overview of CLOCA Tier 1 Approach
• Delineate assessment areas (subwatersheds): • Guidance recommends 20 to 100 km2 assessment area • Estimate Water Demand: • Compile MOE permit data, estimate rural and agricultural water use • Correct water demand for locally returned water (consumptive use) and seasonal usage patterns • Estimate Water Supply: • Tier 1 Guidance allows either spreadsheet or numerical flow model • Modelling approach selected for CLOCA: adapt existing models • USGS MODFLOW (groundwater flow model) • USGS PRMS (Precipitation – Surface Runoff model) • Calculate % Water Demand and assign stress levels
Made possible through the support of the Government of Ontario CTC Source Protection Region
www.ctcswp.ca
CLOCA Subwatersheds: Overview
• Location • South slope of Oak Ridges Moraine • Geologic environment • 1 Minute geologic history of CLOCA • High recharge Oak Ridges Moraine sediments both within and just north of CLOCA study area • Subwatershed Assessment Areas • Surface watershed boundaries not necessarily groundwater shed boundaries (lateral groundwater underflow)
Made possible through the support of the Government of Ontario CLOCACTC Source Subwatersheds Protection Region
www.ctcswp.ca
Bowmanville
CLOCA
Oshawa
Soper
Lynde
Harmony
Darlington
Made possible through the support of the Government of Ontario LandCTC Source Use Protection Classification Region
www.ctcswp.ca
Bowmanville
Oshawa
Soper
Lynde Harmony
Darlington
Made possible through the support of the Government of Ontario CTC SourcePhysiography Protection Region
www.ctcswp.ca
Bowmanville
Oshawa
Soper
Lynde Harmony
Darlington
Made possible through the support of the Government of Ontario CTCSurficial Source Protection Geology Region
www.ctcswp.ca
Bowmanville
Oshawa
Soper
Lynde Harmony
Darlington
Made possible through the support of the Government of Ontario GeologicCTC Source ProtectionCross Section Region
www.ctcswp.ca
B A Oak Ridges Aquifer
Thorncliffe Aquifer
Scarborough Aquifer
B
A
Made possible through the support of the Government of Ontario CTC Source Protection Region
www.ctcswp.ca Subwatershed Assessment Areas
Area • Assessment area logically selected based on historic Watershed km2 Lynde Creek 132 surface water subwatersheds Pringle Creek 28 2 Corbett Creek 15 • Guidance recommends 20 to 100 km areas Goodman Creek 10 2 Oshawa Creek 110 • Selected areas: 6 to 132 km Harmony Creek 47 Farewell Creek 36 Robinson Creek 6 • However: surface watershed boundaries not always a Tooley Creek 11 good indication of groundwatershed boundaries Black Creek 24 Darlington Creek 16 • Multiple aquitard layers isolate the lower aquifers, Bowmanville Creek 90 Westside Creek 6 allowing underflow Soper Creek 75 Bennet Creek 7 Lake Catchments 24 • Model area extends beyond CLOCA boundaries to allow calculation of lateral inflows • Note: Some other studies have assumed that lateral inflows are negligible at a Tier 1 assessment level
Made possible through the support of the Government of Ontario CTC SourceModel Protection Area Region
www.ctcswp.ca
Made possible through the support of the Government of Ontario CTC Source Protection Region
www.ctcswp.ca
Draft Accepted Tier 1 Water Budget for the Central Lake Ontario Source Protection Area WATER DEMAND ESTIMATES
18 Made possible through the support of the Government of Ontario CTC Source Protection Region
www.ctcswp.ca
Consumptive Demand Estimate • Definition: Consumptive demand is the amount of water that is not returned to its original source. • Data Sources: • MOE permit data • Where possible confirmed by CLOCA • Assumed maximum rate, but adjusted for seasonal use • Actual use data not available from MOE • Estimates of rural (un-serviced) demand: current and future • Non-permitted agricultural water use • Estimate based on MOE water well usage codes (irrigation, livestock, orchard, etc. ) • Expired or possible permits: estimated usage • Golf courses with no known permit: estimated usage
Made possible through the support of the Government of Ontario CTC Source Protection Region
www.ctcswp.ca
Consumptive Demand Estimate Corrections • Seasonal usage correction • Many permits are for a limited number of days per year. • Logically allocated over the appropriate months • Even if the permit was issued for 365 days, seasonal usage was estimated based on permit use (golf course, snowmaking) • Consumptive Use: Locally returned water • Tier 1 allows different consumptive approaches: watershed, aquifer, etc. • CLOCA Assessment: Assumed all water consumptive relative to the watershed • Conservative assumption: Return rates taken from MOE guidance (Golf course: 70% consumptive) • Other Tier 1 studies have assumed pumping from deep aquifers would be 100% consumptive
Made possible through the support of the Government of Ontario CTC Source Protection Region
www.ctcswp.ca Overall Groundwater Demand: By Usage
sumption n Co d g n ri service te wa De - 5.4% - Un % .4 Golf 5 - Concrete Plant / Drinking 0.1% 0.6% 2 Dewatering Golf Course Irrigation Maintenance .1% 0 Other- Commercial Snowmaking 0.0% Water Supply
g Unpermitted Agricultural % in .0 k 0 Unserviced Consumption owma Sn - .8% 9
58.6% - Unpermitted Ag.
Made possible through the support of the Government of Ontario CTC Source Protection Region
www.ctcswp.ca Total Groundwater Demand: By Subwatershed
Soper 8% 1% 1% 1%
Bowmanville 11% Lynde , 39%
Darlington 7%
3% 2% 1% 5% 2% 4% 0% Oshawa 14%
Lynde Pringle Corbett Goodman Oshawa Harmony Farewell Robinson Tooley Black Darlington Bowmanville Westside Soper Bennett Lake Ontario
Made possible through the support of the Government of Ontario CTC Source Protection Region
www.ctcswp.ca
Consumptive Demand Estimate: Conclusions
• The consumptive demand estimate is quite uncertain: • Actual permitted water use is not know at this time • Unserviced population and non-permitted agricultural use is estimated
• However: There are no municipal groundwater users in the study area • No Tier 2 level assessment will therefore be required.
Made possible through the support of the Government of Ontario CTC Source Protection Region
www.ctcswp.ca
Draft Accepted Tier 1 Water Budget for the Central Lake Ontario Source Protection Area WATER SUPPLY ESTIMATES
24 Made possible through the support of the Government of Ontario CTC Source Protection Region
www.ctcswp.ca
Water Supply Estimate
• Recharge Estimate • USGS Precipitation Runoff Modelling System (PRMS) • Primarily to estimate groundwater recharge • Calibrate to streamflow estimates at gauges, with underflow corrections estimated from GW model • Lateral Inflows (Qin) • USGS MODFLOW model: GW flux crossing the subwatershed boundary • Water Reserve • Estimated as 10% of the baseflow discharge, as estimated by the MODFLOW Model
Made possible through the support of the Government of Ontario EstimatedCTC Source Protection GW Recharge Region
www.ctcswp.ca
Bowmanville
Oshawa
Soper
Lynde Note high recharge Harmony immediately north of study area Darlington
Made possible through the support of the Government of Ontario GWCTC Levels Source inProtection Lower Region Aquifer
www.ctcswp.ca
Bowmanville
Oshawa
Soper
Lynde Used to estimate lateral Harmony flow rates Darlington
Made possible through the support of the Government of Ontario GWCTC Discharge Source Protection to Streams Region
www.ctcswp.ca
Bowmanville
Oshawa
Soper
Lynde Used to estimate Harmony baseflow reserve Darlington
Made possible through the support of the Government of Ontario CTC Source Protection Region
www.ctcswp.ca
Draft Accepted Tier 1 Water Budget for the Central Lake Ontario Source Protection Area Subwatershed Stress Assessment
29 Made possible through the support of the Government of Ontario CTC Source Protection Region
www.ctcswp.ca Tier 1 – Stress Levels
QDEMAND % Water Demand = x 100
QSUPPLY -QRESERVE
Note: Qsupply = Qrecharge + Q lateral inflow
Surface Water Stress Levels Groundwater Stress Levels
Maximum Monthly Average Maximum Stress Level % Water Demand Stress Level Annual Monthly Assignment Assignment % Water % Water Demand Demand
Significant ≥ 50% Significant ≥ 25% ≥ 50%
Moderate ≥ 20% Moderate ≥ 10% ≥ 25% Low 0 - 19 % Low 0 - 9% 0 - 24%
Made possible through the support of the Government of Ontario CTC Source Protection Region
www.ctcswp.ca Percent Water Demand Results Q % Demand Water Current Demand Stress Watershed Q Q Q Q Condi- Current Level Recharge In Supply Reserve tions Condi- Current (m3/s) (m3/s) (m3/s) (m3/s) (m3/s) tions Conditions Lynde Creek 0.6765 0.2020 0.8785 0.0679 0.0819 10.10 Moderate Pringle Creek 0.1115 0.0420 0.1535 0.0106 0.0043 2.98 Low Corbett Creek 0.0463 0.0170 0.0633 0.0041 0.0001 0.19 Low Goodman Creek 0.0462 0.0150 0.0612 0.0024 0.0009 1.48 Low Oshawa Creek 0.5892 0.1970 0.7862 0.0650 0.0300 4.17 Low Harmony Creek 0.1756 0.0810 0.2566 0.0175 0.0095 3.95 Low Farewell Creek 0.1577 0.1100 0.2677 0.0168 0.0100 4.00 Low Robinson Creek 0.0193 0.0150 0.0343 0.0004 0.0023 6.89 Low Tooley Creek 0.0423 0.0200 0.0623 0.0028 0.0038 6.30 Low Black Creek 0.1243 0.0670 0.1913 0.0106 0.0062 3.44 Low Darlington Creek 0.0702 0.0220 0.0922 0.0043 0.0149 16.97 Moderate Bowmanville Creek 0.6149 0.3050 0.9199 0.0816 0.0239 2.85 Low Westside Creek 0.0180 0.0220 0.0400 0.0013 0.0015 3.76 Low Soper Creek 0.4152 0.2000 0.6152 0.0407 0.0170 2.97 Low Bennet Creek 0.0272 0.0210 0.0482 0.0018 0.0018 3.82 Low Lake Catchments 0.0747 0.1100 0.1847 0.0086 0.0032 1.79 Low
Made possible through the support of the Government of Ontario CTC Source Protection Region
www.ctcswp.ca
Stress Assessment Results:
• Lynde Creek: Moderate stress level • Golf courses • Snowmaking operations • Darlington Creek: Moderate stress level • Quarry operation in lower subwatershed • No municipal supply in either subwatershed, therefore no Tier 2 needed
Made possible through the support of the Government of Ontario CTC Source Protection Region
www.ctcswp.ca Stress Assessment Results: Lateral Inflows • Lateral inflows are equal to between 30% and 144% of the groundwater recharge • Qin is a significant portion of GW supply term • Need to “think outside the watershed” when looking at CLOCA
Q Q Ratio of Area Recharge In Qin/Qrecharge 3 3 Watershed km2 (m /s) (m /s) Percent Lynde Creek 132 0.677 0.202 30% Pringle Creek 28 0.112 0.042 38% Corbett Creek 15 0.046 0.017 37% Goodman Creek 10 0.046 0.015 32% Oshawa Creek 110 0.589 0.197 33% Harmony Creek 47 0.176 0.081 46% Farewell Creek 36 0.158 0.110 70% Robinson Creek 6 0.019 0.015 78% Tooley Creek 11 0.042 0.020 47% Black Creek 24 0.124 0.067 54% Darlington Creek 16 0.070 0.022 31% Bowmanville Creek 90 0.615 0.305 50% Westside Creek 6 0.018 0.022 122% Soper Creek 75 0.415 0.200 48% Bennet Creek 7 0.027 0.021 77% Lake Catchments 24 0.075 0.110 NA
Made possible through the support of the Government of Ontario CTC SourceGW Protection Supply Region
www.ctcswp.ca
Bowmanville
Oshawa
Higher supply in subwatersheds that reach the ORM Soper
Lynde Harmony
Darlington
Made possible through the support of the Government of Ontario CTCPercent Source ProtectionGW Demand Region
www.ctcswp.ca
Bowmanville
Oshawa
Higher Percent demand in Lynde and Darlington Soper
Lynde Harmony
Darlington
Made possible through the support of the Government of Ontario CTCTier Source 1 Stress Protection Level Region
www.ctcswp.ca
Bowmanville
Oshawa
Lynde and Darlington exhibit moderate GW stress Soper
Lynde Harmony
Darlington
Made possible through the support of the Government of Ontario CTC SWSource Stress Protection Level Region
www.ctcswp.ca
Bowmanville
Oshawa
SW Stress levels based on high demand during low summer flows Soper
Lynde Harmony
Darlington
Made possible through the support of the Government of Ontario CTC Source Protection Region
www.ctcswp.ca
Stress Assessment: Conclusions
• Lynde and Darlington Creeks classified as moderate stress level • No municipal groundwater supply, therefore no need to proceed to a Tier 2 assessment • Considerable uncertainty in the water demand estimates • Advanced modelling techniques used to estimate water supply • Modelling analysis essentially at a Tier 2 level • Lateral groundwater inflows account for a significant portion of the water supply term
Made possible through the support of the Government of Ontario CTC Source Protection Region
www.ctcswp.ca
Comments on Stress Assessment: Field Verification
• Cumulative flow analysis of stream gauge data can indicate if stress is real • Example: Cumulative flow for Oshawa Creek: 1959-2003 • Deviation from linear trend suggests increasing consumptive stress
Made possible through the support of the Government of Ontario CTC Source Protection Region
www.ctcswp.ca
Draft Accepted Tier 1 Water Budget for the Central Lake Ontario Source Protection Area Significant Recharge Areas
40 Made possible through the support of the Government of Ontario CTC Source Protection Region
www.ctcswp.ca
SGRA: Significant Groundwater Recharge Areas
• SGRA and High Volume Recharge Areas (HVRA) calculated using a number of guidance recommended methods • Cell-based PRMS Recharge estimate can be adapted and re- processed with different threshold levels to estimate SGRA areas • Need to consider: • Shallow versus deep groundwater flow system • Municipal water supply source must be considered in defining significance
Made possible through the support of the Government of Ontario CTC Source Protection Region
www.ctcswp.ca
The Technical Rules prescribe the following equations. Part V.2 - Delineation of significant groundwater recharge areas 41. Subject to rule 42, an area is a significant groundwater recharge area if, (1) the area annually recharges water to the underlying aquifer at a rate that is greater than the rate of recharge across the whole of the related groundwater recharge area by a factor of 1.15 or more; or (2) the area annually recharges a volume of water to the underlying aquifer that is 55% or more of the volume determined by subtracting the annual evapotranspiration for the whole of the related groundwater recharge area from the annual precipitation for the whole of the related groundwater recharge area. 42. Despite rule 41, an area shall not be delineated as a significant groundwater recharge area unless the area has a hydrological connection to a surface water body or aquifer that is a source of drinking water for a drinking water system.
Made possible through the support of the Government of Ontario CTC SGRA:Source Protection Method Region 4
www.ctcswp.ca
Bowmanville
Oshawa
SGRA
Soper
Lynde Harmony
Darlington
Made possible through the support of the Government of Ontario CTC SGRA:Source Protection Method Region 5
www.ctcswp.ca
Bowmanville
Oshawa
SGRA
Soper
Lynde Harmony
Darlington
Made possible through the support of the Government of Ontario SGRA:CTC Source Particle Protection Tracking Region
www.ctcswp.ca
Bowmanville
Oshawa
Reverse particle tracking from high discharge stream reaches Soper illustrates SGRAs and significant underflow Lynde Harmony
Darlington
Made possible through the support of the Government of Ontario CTC Source Protection Region
www.ctcswp.ca
SGRA Conclusions
• PRMS Recharge Model indicates that recharge is highly variable on both a seasonal and spatial basis • SGRA analysis cannot simply look at surficial materials: • Shallow Iroquois Beach sand deposits in the southern portion are thin and not directly connected to the deeper aquifer system • Particle tracking indicates: • Significant recharge occurs outside of the study area • Underflow is important: Bowmanville discharge can be traced under Soper Creek to a recharge location outside of the subwatershed. • SGRA Thresholds can be adjusted as necessary
Made possible through the support of the Government of Ontario CTC Source Protection Region
www.ctcswp.ca
Draft Accepted Tier 1 Water Budget for the Central Lake Ontario Source Protection Area CONCLUSIONS
47 Made possible through the support of the Government of Ontario CTC Source Protection Region
www.ctcswp.ca
Tier 1 Water Budget Report Conclusions • Lynde and Darlington Creeks classified as Moderate Stress Level under current and future demand conditions. • No municipal groundwater sources exist in these subwatersheds • Tier 2 level analysis is not needed. • Considerable uncertainty in the water demand estimates. Major uses: • Non-permitted agricultural: 59% • Golf courses: 21% • Snowmaking: 10% • Dewatering: 5% • Need to confirm actual water use from MOE and other sources
Made possible through the support of the Government of Ontario