identifying & protecting recharge areas

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Identifying & Protecting Identifying & Protecting Recharge AreasRecharge Areas

Source Water Protection Source Water Protection SymposiumSymposium

April 18, 2007April 18, 2007

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Source Water ProtectionSource Water ProtectionAt its root, source water protection is about At its root, source water protection is about UNDERSTANDING THE WATERSHED FLOW UNDERSTANDING THE WATERSHED FLOW SYSTEM SYSTEM –– Pathways and Quantities of waterPathways and Quantities of water

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Source Water ProtectionSource Water Protection

Source Water ProtectionSource Water ProtectionSource Source ‘‘aterater protectionprotectionSource Source aeraer protectionprotection……………………..

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SORCERERPROTECTION

The Hydrogeologist

as “Sourcerer”The Sorcerery

behind Source Water

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Recharge Recharge

Recharge is the process by which water Recharge is the process by which water moves from the ground surface, through moves from the ground surface, through the unsaturated zone, to arrive at the the unsaturated zone, to arrive at the water table.water table.

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Areas of Lower Recharge

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Areas of Higher Recharge

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Technical Experts CommitteeTechnical Experts CommitteeRecommendation 66Recommendation 66

Significant recharge areas must be Significant recharge areas must be delineated through the source water plans delineated through the source water plans and will be considered vulnerable from and will be considered vulnerable from both a quality and quantity perspective. both a quality and quantity perspective. Source protection plans will consider these Source protection plans will consider these areas as: vulnerable to urbanization which areas as: vulnerable to urbanization which can restrict recharge to subsurface can restrict recharge to subsurface aquifers; and vulnerable to cumulative aquifers; and vulnerable to cumulative contaminant loading impacts.contaminant loading impacts.

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OntarioOntario’’s Source Water Programs Source Water ProgramMODULE 3 MODULE 3 –– Groundwater Vulnerability Groundwater Vulnerability AnalysisAnalysis

Map & assess vulnerability of wellhead Map & assess vulnerability of wellhead protection areasprotection areasAssess vulnerability outside of wellhead Assess vulnerability outside of wellhead protection areas to identify other protection areas to identify other ““vulnerable vulnerable areasareas”” –– e.g. e.g.

•• Significant Recharge AreasSignificant Recharge Areas•• Highly Vulnerable AquifersHighly Vulnerable Aquifers•• Future Municipal Supply AreasFuture Municipal Supply Areas

Assign vulnerability scoresAssign vulnerability scores

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Recharge Recharge –– Other LegislationOther LegislationORM PlanORM Plan

The purpose of Natural Core Areas is to maintain and where possible improveor restore the ecological integrity of the Plan Area, by,

• maintaining the quantity and quality of groundwater and surface water;• maintaining groundwater recharge;

Provincial Policy StatementDefines groundwater features to include recharge/discharge areas (amongst other features)Planning authorities shall protect, improve or restore the quality and quantity of water by:

• identifying surface water features, ground water features, hydrologic functions and natural heritage features and areas which are necessary for the ecological and hydrological integrity of the watershed;

• implementing necessary restrictions on development and site alteration to: protect all municipal drinking water supplies and designated vulnerable areas; and protect, improve or restore vulnerable surface and ground water, sensitive surface water features and sensitive ground water features, and their hydrologic functions by;

• maintaining linkages and related functions among surface water features, ground water features, hydrologic functions and natural heritage features and areas;

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Other JurisdictionsOther Jurisdictions

Washington State Washington State –– Critical Aquifer Critical Aquifer Recharge Areas (CARA) Recharge Areas (CARA)

Under Growth Management ActUnder Growth Management Act““Areas with a critical recharging effect on Areas with a critical recharging effect on aquifers used for potable water.aquifers used for potable water.””Goal Goal –– ““to protect function and values of to protect function and values of communitycommunity’’s drinking water by preventing s drinking water by preventing pollution and maintaining supply.pollution and maintaining supply.””More focus on quality than quantityMore focus on quality than quantity

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NEW JERSEY

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Difficulties with Recharge MappingDifficulties with Recharge Mapping1.1. Recharge can occur almost anywhereRecharge can occur almost anywhere2.2. Natural breaks in the continuum from high to low are Natural breaks in the continuum from high to low are

rarerare3.3. All recharge is important to the GW system and linked All recharge is important to the GW system and linked

SW featuresSW features4.4. Recharge is transient Recharge is transient –– maps are steady statemaps are steady state5.5. Anthropogenic features can alter rechargeAnthropogenic features can alter recharge6.6. Accurate measurements are difficult to obtainAccurate measurements are difficult to obtain7.7. Shallow aquifers are most sensitive to changes in Shallow aquifers are most sensitive to changes in

recharge but are usually not water supply aquifersrecharge but are usually not water supply aquifers8.8. No standard scientific method exists for delineation of No standard scientific method exists for delineation of

recharge areas.recharge areas.

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Ontario Source Water ProtectionOntario Source Water Protection

Two step process proposed:Two step process proposed:1.1. Determine High Volume recharge areasDetermine High Volume recharge areas2.2. Determine Determine ““SignificanceSignificance””

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High Volume Recharge AreasHigh Volume Recharge Areas

High Volume Recharge AreasHigh Volume Recharge AreasSurficialSurficial geologygeologyAreas with >55% of surplus (PAreas with >55% of surplus (P--ET)ET)Areas with 1.15x annual average recharge Areas with 1.15x annual average recharge rate to rate to subwatershedsubwatershed

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Attaching term Attaching term ““SignificantSignificant””

Linkage to an area to an aquifer or well Linkage to an area to an aquifer or well that is used for municipal supplythat is used for municipal supplyLinkage to a cold water ecosystem that is Linkage to a cold water ecosystem that is dependant on recharge to maintain dependant on recharge to maintain functionfunction

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CAMC – Oak Ridges Moraine Focused GW Program

1818DETAILED WATER BUDGET

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Factors Being Considered in Recharge Factors Being Considered in Recharge Determinations in OntarioDeterminations in Ontario

Hummocky TopographyHummocky TopographySurficialSurficial materials (OGS/GSC)materials (OGS/GSC)SlopeSlopeWater table depthWater table depthClimateClimateLand Use/UrbanizationLand Use/Urbanization

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Figure 1: Discrepancies between map sheets for hummocky topography mapping

2121Glaciofluvial outwash plain with few mounds but many sinks.

2222Irregular topography with many mounds and few sinks.

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~243 km2

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Holland River profile

Holland Marsh(polders)

Profile Along East Holland River

2525SURFICIAL GEOLOGY

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Holland Watershed Method #1Holland Watershed Method #1

Surplus ~ 290 mm/yrSurplus ~ 290 mm/yr55% = 160 mm/yr55% = 160 mm/yr

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Holland Watershed Method #2Holland Watershed Method #2

Average Recharge = Average Recharge = 162 mm/yr162 mm/yr1.15 x 162 = 186.3 1.15 x 162 = 186.3 mm/yrmm/yr

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Accuracy?Accuracy?

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Particle Tracking from key discharge areas

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Fish Habitat

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Unsaturated Travel TimesUnsaturated Travel Times

Source Water Guidance Modules also Source Water Guidance Modules also speak to the Unsaturated Zonespeak to the Unsaturated ZoneHave to consider the heterogeneity of Have to consider the heterogeneity of surficialsurficial geology and the depth to the geology and the depth to the water tablewater table

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UZATBetween 0 and 10 yrs

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Protecting Recharge AreasProtecting Recharge Areas

QuantityQuantityImpervious surfacesImpervious surfacesPromote infiltrationPromote infiltration

QualityQualityStorm waterStorm waterSpillsSpillsIndustrial land usesIndustrial land uses

OP Planning/Watershed PlanningOP Planning/Watershed Planning

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A History of Source Water Frustration in Ontario (pre 2004) …..

identifying & protecting recharge areas

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