57ième CONGRÈS CANADIEN DE GÉOTECHNIQUE 57TH CANADIAN GEOTECHNICAL CONFERENCE5ième CONGRÈS CONJOINT SCG/AIH-CNN 5TH JOINT CGS/IAH-CNC CONFERENCE

INTEGRATED GROUNDWATER RESOURCE ASSESSMENT OF FRACTURED BEDROCK AQUIFERS IN THE GULF ISLANDS, BC Murray Journeay, Geological Survey of Canada (Vancouver), CanadaShannon Denny, Geological Survey of Canada (Vancouver), CanadaDiana Allen, Simon Fraser University (Burnaby), CanadaCraig B. Forster, University of Utah (Salt Lake City), U.S.A. Robert Turner, Geological Survey of Canada (Vancouver), CanadaMike Wei, BC Ministry of Water, Land and Air Protection (Victoria), Canada

Abstract: The Gulf Islands are a network of small rural island communities located in the Georgia Basin region of Southwestern BritishColumbia. They are representative of many communities across Canada that depend primarily on groundwater for domestic and agriculturaluse. Situated in the active forearc of the Cascadia subduction/accretion complex, the structurally–controlled fractured bedrock aquifers in this region are highly partitioned, difficult to map in detail, and vulnerable to both overuse and contamination. Increased water demand frompopulation growth and development have already contributed to salt water intrusion, increased numbers of abandoned wells and significantdeclines in water quality during the summer months. Working in collaboration with groundwater professionals in the public, private andacademic sectors, we have developed a suite of models to derive an assessment of aquifer vulnerability and sustainable yield in the GulfIsland region. Our intent is to help decision makers better understand the complex hydrogeology of the region and to incorporate this understanding into a planning and policy development context across both local and regional jurisdictional levels of government. Collectively,these resource assessment models provide a means of evaluating the impacts of current land use strategies on available water resources in the Gulf Islands, and a framework for exploring alternate strategies for resource management.

Résumé: Les îles du Golfe sont un réseau de petites communautés rurales situées dans la région du bassin de Georgia en Colombie-Britannique. Elles représentent plusieures communautés à travers le Canada qui dépendent principalement sur les eaux souterraines pour les utilisations domestique et agricole. Situés dans le bassin d’avant-arc actif de la zone de subduction et d’accrétion Cascadia, les aquifères contrôlés par les éléments structuraux de la roche en place sont fortement fracturés, difficiles à tracer en détail et vulnérables à la surconsommation et à la contamination. Une demande accrue en eau en raison de la croissance de population et du développement a déjà contribué à l'intrusion d'eau salée, à l’abandon d’un grand nombre de puits et à la déterioriation importante de la qualité de l'eau pendantl'été. En collaboration avec des spécialistes en eau souterraine des secteurs publics, privés et scolaires, nous avons développé une suite de modèles pour dériver une évaluation de la vulnérabilité des aquifères et le rendement durable dans la région des îles du Golfe. Notre proposest d'aider aux décideurs à comprendre l'hydrogéologie de la région et d'incorporer cette notion dans un contexte de politiques dedéveloppement et d’aménagement pour toutes les juridictions locales et régionales du gouvernement. Ensemble, ces modèles d'évaluationde ressource fournissent des moyens d'évaluer les impacts des stratégies courantes d’aménagement et d’urbanisme sur les ressourcesd'eaux souterraines disponibles dans les îles du Golfe. De plus, les modèles,peuvent développer un cadre pour explorer de nouvellesstratégies de gestion de la ressource.

1. CONTEXT AND FOCUS

The Georgia Basin (Figure 1) is home to the urban centersof Vancouver and Victoria, and one of the most denselypopulated and fastest growing bioregions in Canada. Witha population growth rate of thirty-five percent, it is anticipated that the region will swell to approximately fourmillion people by the year 2020 (Georgia Basin-PugetSound Ecosystem indicators Report, 2002). Over thissame period of time, it is estimated that regional impacts ofglobal climate change will likely reduce surface watersupplies and rates of recharge, thereby placing increasingdemands on available groundwater resources. Thesetrends underscore the need for tighter coupling betweenongoing scientific research, land use planning and watermanagement strategies if we are to collectively maintainand protect renewable groundwater resources that will berequired to balance competing economic, environmentaland human needs in the region.

This paper highlights Phase I results of an ongoingcollaborative project aimed at bridging the gap betweengroundwater science, policy development and communityplanning in the southern Gulf Island region of the GeorgiaBasin. We describe methodologies for assessing intrinsicvulnerability and sustainable yield in fractured bedrockaquifers and explore strategies for situating the outputs ofthese assessments more directly in a planning and policydevelopment context. The initial phase of this project(Phase I) was undertaken as part of the aquifer

characterization and mapping component of the GeologicalSurvey of Canada Groundwater (GSC) Program. Theproject brings together expertise in the fields of groundwater hydrogeology, bedrock geology, structuralgeology and tectonics, GIS and modeling, education andcommunity outreach, and represents an interactive

Figure 1: The Georgia Basin, British Columbia(Transboundary Georgia Basin-Pudget Sound

Environmental Ecosystem Indicators Working Group, 2002)

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partnership between academia, Federal and Provincialscience agencies, regional planners and membercommunities in the Gulf Island region.

2. BACKGROUND

The Gulf Islands (Figure 2) comprise an archipelago of thirteen island communities situated in the rural heartland ofthe Georgia Basin, between the Greater VancouverRegional District (GVRD), the Capital Regional District(CRD) of Victoria and rapidly growing communities in theadjacent Cowichan Valley, Nanaimo and Sunshine Coastregional districts. The islands are topographically subdued(100-350m) with limited surface water supplies, and arecharacterized by glaciated ridges and valleys that mirror thegeometries of underlying bedrock formations. Structurallycontrolled bedrock aquifers and, to a lesser extent,unconfined shallow (<18m) granular aquifers are theprinciple groundwater resources in the region, supplyingmore than eighty percent of the existing needs for domesticand agricultural use.

Although prospective, most of the deeper and more reliablebedrock groundwater systems are structurally complex,poorly understood from a hydrogeological perspective, andbeyond the scope of existing aquifer assessment andmapping methodologies (Aller et al., 1987; Ronneseth etal., 1995). Overuse of these fractured bedrock aquifers inseveral Gulf Island communities has already contributed toinstances of saltwater intrusion, an increasing number ofabandoned wells and measurable declines in water qualityin the summer months. The susceptibility of these aquifersto overuse and contamination can be expected to increaseas population densities, development infrastructures and

the demand for reliable community water resourcescontinue to grow in the region.

2.1 POLICY FRAMEWORK

Provincial legislation in 1975 established the Islands Trustas a federation of local island governments with regionalplanning authority and a mandate to “preserve and protectthe trust area and its unique amenities and environment forthe benefit of the residents of the trust area and of BritishColumbia generally, in cooperation with municipalities,regional districts, improvement districts, other persons andorganizations and the government of British Columbia"(Islands Trust, 2003). By 1987, the Islands Trust Act wasamended to include local community planning authority,comparable to that of a regional district operating underguidelines of the Municipal Act. In 1993, the Trust PolicyStatement bylaw was enacted as a planning framework tohelp guide decisions on growth management and land-useissues for the region and within individual islandcommunities. The bylaw encompasses a number of policyguidelines that specifically address groundwater resourcemanagement in the Trust area, including conservation ofwetlands and recharge areas, alternate strategies fordemand-side management and support for localstewardship activities.

It is the cumulative impact of individual and collectivedecisions made at the community and regional district levelthat have the most significant impact on the protection andmanagement of groundwater resources. And, it is at thislevel of policy development and decision-making where theoutputs of academic, private sector and federal-provincialgroundwater studies (information knowledge and expertise)are most relevant, yet often least accessible.

Vancouver

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3. BRIDGING THE SCIENCE-POLICY GAP

Like many rural communities across Canada, the GulfIslands have built up a wealth of local knowledge andexpertise over the years to address issues relating togroundwater resource management, including strategies formitigating effects of surface contamination and overconsumption. Much of this knowledge resides with localplanners, water purveyors and community stewardshipgroups acting on behalf of their constituents. It is, however,not always well-integrated with ongoing groundwaterresearch in academic and/or public science sectors, and isoften not accessible to those making decisions at otherjurisdictional levels of government.

In an effort to bridge these gaps in understanding and tobroaden the network of collaboration, the Gulf IslandGroundwater Initiative undertook the design and facilitationof a series of consultation workshops through interactivepartnerships with the Islands Trust and membercommunities of the Trust area. The intent of the workshopprocess was to share information and knowledge on keywater resource issues in the region, and to co-develop aneducational poster (Waterscapes) and accompanyingoutreach materials to help promote understanding and wiseuse of freshwater resources by island residents and visitorsto the Gulf Islands. The community engagement processwas coordinated through a steering committee which

Figure 2: The Gulf Islands

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included elected officials, planners, groundwaterprofessionals, educators and volunteer stewardshipcoordinators.

Collectively, the working group identified eight key waterissues for the region; 1) water conservation, 2) seasonalprecipitation, 3) freshwater storage, 4) water for ecosystemuse, 5) hydrogeology of fractured bedrock aquifers, 6)aquifer vulnerability, 7) water scarcity and 8) land usestrategies. Following this initial phase of issueidentification, the working group then determined keymessages for each of the major topics and worked withGSC staff to design and develop a suite of scientific illustrations and accompanying storylines to represent andcommunicate key concepts of groundwater science andresource management in the region. Results of this workled to the joint publication of a ‘Waterscapes’ poster series(Turner et al., 2004) and accompanying on-line resourcesfor use in support of ongoing community outreach andstewardship activities across the Gulf Island region (Figure3).

Through this process of collaborative design and deliberation, the working group also succeeded in evolvinga shared understanding of structurally controlled bedrockaquifer systems, and in identifying strategies to helpcoordinate and promote a science-based approach togroundwater resource management in the Gulf Islands. Itis within this context, and with the intent of supportingongoing regional and community planning activities, that weundertook the next step in the process of developing anintegrated modeling framework for assessing the intrinsicvulnerability and sustainable yield of structurally controlledbedrock aquifers in the region.

2. GROUNDWATER RESOURCE ASSESSMENT

The majority of bedrock aquifers in the Gulf Island regiontend to be highly partitioned, difficult to map in detail, andvulnerable to both overuse and contamination. They arehosted primarily in folded and faulted sedimentary rocks ofthe Nanaimo Group (forearc basin assemblage) or instructurally complex metamorphic and plutonic rocks(accreted island arc assemblages) of an underlyingcrystalline basement complex, known as Wrangellia. Theregion is situated in the forearc of the active Cascadiasubduction/accretion complex and records a Neogene(21Ma-recent) history of brittle faulting and associateddeformation.

The geometry and kinematics of these cross-cutting brittlestructures reflect a process of inhomogeneous strainpartitioning in the upper crust that is believed to beassociated with both margin-normal and margin-parallelshortening along the active plate margin of North America(Journeay and Morrison, 1999). Bedrock aquifers awayfrom major fault and fracture systems are characterized by

relatively low hydraulic conductivity and low primaryporosity (~0.05%). Previous hydrogeologic studies anddrilling reports (e.g., Hodge, 1995; Dakin et al., 1983; Allenet al., 2002) have demonstrated that the majority ofprospective bedrock aquifers are channeled along theyounger Neogene fault and fracture systems, and arecharacterized by variable but increased secondarypermeability.

Informed by the results of ongoing process-basedhydrogeologic modeling in the southern Gulf Islands (Allen,et al., 2002), we have developed a framework for integratedresource assessment that focuses primarily on regionalgroundwater protection and resource managementobjectives (characterizing aquifer vulnerability and

Figure 3: Surface/groundwater interactions in the Gulf Islands (Turner et al., 2004)

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sustainable yield) and, to a lesser extent, on the process ofgroundwater flow within individual bedrock aquifers. Theframework is based on a conceptual model that describesthe overall hydrogeogic setting of structurally controlledgroundwater flow systems in the Gulf Islands (Mackie,2000; Mackie et al., 2001), and includes both a multi-parameter geospatial index model (Denny et al. (in prep.))for assessing intrinsic vulnerability of structurally controlledbedrock aquifers, and a stock-flow (STELLA©) waterbudget model (Forster and Journeay (in prep.)) forevaluating overall sustainable yield of freshwater resourcesin the Gulf Island region. Outputs of these resourceassessment models are combined with socio-economicinformation in the context of an integrated assessmentmodeling framework to assist planners and resourcemanagers in evaluating trade-offs associated with alternateland use development and regional growth strategies.

2.1 CONCEPTUAL MODEL

The general hydrogeologic model proposed for the GulfIslands (Mackie et al., 2001, Mackie, 2000) is based on theconcept of hydrostructural domains, which are defined onthe basis of lithology and structural setting. The modeltakes into account combinations of fracture density,orientation, aperture and proximity to cross-cutting faultsand fracture systems, and defines the hydrogeologicsystem in terms of five major components (Figure 4); Unit1: thin (<18m), unconfined granular aquifers, largelysituated in valley bottoms, Unit 2a: massive sandstone-dominated units with relatively low background fractureintensity and low permeability, Unit 2b: intercalatedmudstone-dominated units characterized by a closely-spaced fracture cleavage foliation and elevated primarypermeability, Unit 3a: cross-cutting composite fault zonesand Unit 3b: discrete fault-fracture networks marked bybrittle fracturing, local brecciation and relatively highsecondary permeability.

2.2 INTRINSIC AQUIFER VULNERABILITY

Although routine practice in unconfined granular aquifers, afull assessment of aquifer vulnerability in fractured bedrocksystems requires a thorough understanding of structurally

controlled fluid-rock interactions over time, process-basedmodeling of the rates and directions of groundwater flow,and detailed information on the composition, location andintensity of point and non-point sources of contamination.As a result, these studies are usually limited in spatialextent, targeted on specific types and/or sources ofcontamination, and require ongoing collaboration withgroundwater scientists to translate model outputs andassociated uncertainties (vulnerability and risk) into a planning and/or policy development context (Focazio et. al.,2002).

Intrinsic aquifer vulnerability is a more general form of resource assessment that reflects both the physicalcharacteristics of the groundwater flow system (intrinsicsusceptibility) and the potential for naturally occurringand/or anthropogenic sources of contamination to enter theaquifer over time. Assessment of intrinsic vulnerability canbe undertaken at a regional scale using a combination ofgeospatial and/or statistical modeling techniques. Outputs of these models provide map-based representations ofrelative vulnerability (high, medium and low), and are oftenused as an overarching framework within which to situatemore detailed process-based studies of aquifervulnerability. Although subjective, assessment of intrinsicaquifer vulnerability provides an efficient means ofintegrating expert and local knowledge of groundwaterresources, and is more easily translated into a regionalplanning and/or policy development context.

4.2.1 METHODOLOGY

In an effort to balance resource management objectivesand available information on groundwater flow and potentialsources of natural and anthropogenic contamination in theGulf Islands, we opted for a more general index-basedapproach that extends the well-known DRASTICmethodology (Aller et al., 1987) of intrinsic vulnerabilityassessment for use in more complex fractured bedrockaquifers. The standard methodology involves theintegration of available information on physical aquifercharacteristics, including depth to water table (D), netrecharge (R), aquifer media (A), soil media (S), topographicslope (T), impact of vadose zone (I) and hydraulicconductivity of the aquifer (C). Using a raster-based GISmodeling framework (Denny et al. (in prep)), we integratedwater well and digital terrain data with information onbedrock geology, soil type and hydraulic conductivity (pumptest results) to evaluate the standard DRASTIC parametersfor the Gulf Islands. Rates of net groundwater recharge (R)were calculated using the US EPA model HELP (UnSatSuite, Waterloo Hydrogeologic Inc.). The effects of cross-cutting fault and fracture networks and regional tectonicstresses were evaluated by compiling information gatheredthrough remote sensing and field-based structural studiesin the Cascadia forearc (Journeay and Morrison, 1999;Mackie, 2000). Physical characteristics of individual faultand fracture systems, including width, length, fractureintensity, connectivity and orientation with respect toregional tectonic stress, were used in deriving an additionalparameter (Fm) to extend the DRASTIC framework forassessing the effects of secondary permeability on intrinsicvulnerability in fractured media.

Figure 4: Conceptual Model for hydrostructural andhydrostratigraphic domains of the Gulf Islands (Mackie, 2000)

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4.2.1 RESULTS

This modified version of index assessment, known asDRASTIC-Fm (Denny et al. (in prep)), provides a means ofcharacterizing and mapping intrinsic susceptibility andassessing intrinsic vulnerability of fractured aquifers in theGulf Islands due to a range of potential hazards, includingsalt water intrusion in coastal areas that are exposed toover pumping, and various types of point and non-pointsource contamination (Figure 5).

The model is highly sensitive to variations in soil media,depth to water table and proximity to known fault andfracture systems. Regions of low and moderatesusceptibility (36-106) occur at higher elevations in areaswhere depth to the water table is greatest. These are, however, also regions of groundwater recharge and wouldbe more highly vulnerability to surface contamination.Regions of moderate and high susceptibility (106-194)occur along northerly trending fault and fracture systems(Units 3a and 3b), in areas where the water table is within20 meters of the surface, and in areas underlain by coarse-grained glacial sediments (Unit 1) or fractured mudstone-dominated bedrock units of the Nanaimo Group (Unit 2b).Areas of moderate and high susceptibility that are also

within groundwater recharge zones would be mostvulnerable to surface contamination. Regions of highsusceptibility and that are most vulnerable to saltwaterintrusion occur along desirable coastal shorelines wherecumulative pumping rates are high, and in places where theshoreline is transected by northerly-trending fault andfracture systems. Overall, there is good correlation betweenmodel outputs and water chemistry data that recordinstances of saltwater intrusion and with measured wateryield along identified zones of increased secondarypermeability.

DRASTIC-Fm model outputs provide a means of systematically mapping aquifer characteristics and intrinsicvulnerability for fractured bedrock groundwater systems,but do not provide an objective measure of uncertainty. Assuch, they are intended primarily as a means ofestablishing a regional framework of groundwater resourceassessment in which to situate more detailed process-based studies of groundwater flow and aquifer vulnerability.The hand-off and interpretation of these results to waterresource decision makers would require further deliberationto both fine-tune model outputs for specific managementobjectives (vulnerability to salt water intrusion, rechargeprotection areas, etc), and to translate the outputs into a set

DRASTIC-FmIntr insic Vulnerability

Value

Low (36-77)

Low-Moderate (77-92)

Moderate (92-106)

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High (124-194)

A

Figure 5: Characterization of intrinsic groundwater susceptibility in the Gulf Islands.

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of corresponding policy guidelines that could be used in thecontext of land use and/or strategic planning.

3. SUSTAINABLE YIELD

In addition to being vulnerable to surface contamination andsaltwater intrusion, fractured bedrock aquifers of the GulfIslands are also vulnerable to over-consumption. Many ofthe islands experience water shortages during summermonths, when yearly supplies of surface and groundwaterare lowest and cumulative demands from both full-timeresidents and seasonal visitors are highest. Theseseasonal fluctuations are exasperated by longer-termtrends in climate change, increasing population growth inthe region and associated impacts of developmentinfrastructure and changing land use. For the purposes ofthis study, we interpret sustainable yield to be a state of dynamic equilibrium in which current and projecteddemands on available freshwater resources do not exceedthe capacity of surface and groundwater supplies tobalance environmental and human needs over longer-termstrategic planning horizons (10-40 years). It is a moregeneral form of a water budget calculation in which ratesand fluxes in recharge and groundwater flow can bequantified, usually at the scale of an individual aquifersystem.

Assessment of sustainable yield for an island systemrequires information on current and projected demand(environmental, residential, commercial and industrial),estimates of overall surface and groundwater supply, andpotential impacts of climate change. Variables that havethe greatest impact on overall yield include rates of population growth, changing patterns of human settlementand water use and overall rates of recharge, which can beinfluenced by impacts of climate change and land usepractices. Given the number of variables and associated

uncertainties, we opted for a backcasting approach toevaluating sustainable yield. Backcasting (Robinson, 1982)is an approach to systems modeling that involves workingbackwards from a particular desired future end-point or setof goals to the present, in order to determine the feasibilityof that future and the policy measures that would berequired to reach that point. Backcast models dealexplicitly with uncertainty by expressing system behaviourin terms of feasibility, choices and consequences, and aredesigned to focus on management objectives bydetermining the freedom of action, in a policy sense, withrespect to possible futures (Tansey et al., 2004).

3.1 METHODOLOGY

Working in collaboration with Craig Forster at the Universityof Utah (Forster and Journeay (in prep.)), we havedeveloped and prototyped a backcast model in STELLA©

for assessing sustainable water yield in island systems.The model, illustrated schematically in Figure 6, capturesprincipal aspects of the hydrogeologic setting in the Gulf Islands (Surface Water Supply and Groundwater SupplySectors) and provides a means of accounting for climatechange, population growth (Housing Growth Sector), andchanging patterns of settlement and associated water use(Water Use sector). Each node in the model represents asystem variable that is expressed numerically as anassumption, or as an algorithm (indicator) that reflects changing properties of the system over time. Nodes areconnected by flows (curved lines in Figure 6) that makeexplicit the interactions between system components,including dependencies, causal relationships and feedbackloops. These interactions are expressed through acombination of IF-THEN-ELSE logic rules andmethodologies for evaluating system components that varycontinuously over time.

Figure 6: Systems flow diagram of the Gulf Islands sustainable yield model. (Forster and Journeay (in prep.))

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The STELLA© map also makes explicit those componentsof the model where human decisions (Personal Choice,Business Decision, Policy Decision) are made that canaffect the way the system operates. For example, acombination of personal choice (household size, desire tomove to or from the island) and policy decisions (land useregulations and zoning) affect anticipated growth inconstruction of homes for a growing population. In addition,during periods of low precipitation a farmer may make abusiness decision to fallow crops or change to low water-use crops. These decisions and choices may be affected,in part, by knowledge that aquifer water levels are decliningor by the reality of water shortages (when the availablewater is insufficient to supply the desired use). At present,only a subset of the possible choices and decisions areexplicitly implemented in the model. Options are provided,however, for adjusting input parameters in ways that mightreflect specific decisions or choices that might be made inthe future.

3.2 RESULTS

For purposes of testing the model, we used availabledatasets for Bowen Island (Figure 2), where detailedinformation on population growth, sources of waterdistribution (wells, surface water intakes, serviceconnections, etc.) and rates of water use have beengathered and maintained over the years by water systempurveyors and local stewardship groups. If default settingsfor water demand, water use and water supply are heldconstant throughout a 50-year simulation period (1980-2030), the results indicate that sustainable yield would beexceeded within the next 25-30 years.

In this scenario, it is assumed that total water usedincreases with population growth. Because the water madeavailable by capturing surface runoff is held constant,growth in water used is supported only by growth in wellproduction as new wells are drilled. After about 2005,however, the addition of new wells fails to supply theadditional water needs and the gap between water wantedand water used (grey zone in Figure 7) grows over time.Continued growth in well production leads to rapid declinein the active aquifer volume (grey solid line in Figure 7) andconcern that the groundwater resource may be damagedby overexploitation.

The point of sustainable yield in this scenario, that is the time at which the community would begin to mine available

freshwater reserves, occurs between 2030 and 2035.Based on density allocations in the existing land use bylawfor Bowen Island and current trends in population growth,this is also the time at which it is anticipated the communitywould reach build-out. Policy options that might beimplemented to mitigate long-term drought include: waterconservation, changes in agricultural practices, increasingsurface runoff capture capacity, augmenting water supplieswith desalination of sea water, and restrictions ongroundwater pumping rates.

What-if scenarios generated by adjusting variables andassumptions in the model provide a means of visualizingand understanding complex system dynamics, exploringmore deeply the linkages between choices andconsequences, and identifying potential strategies(demand-side management, land use practices, etc) formitigating the effects of increasing demand and fluctuationsin supply. System variables and policy options would needto be revised in consultation with island residents and localgovernment in order to more fully calibrate the model withlocal knowledge, to assess potential constraints (economicand public acceptance) and to identify targets andstrategies for moving forward.

4. NEXT STEPS

We are working with the Islands Trust and communitypartners in the Gulf Islands to further refine ourassessments of intrinsic vulnerability and sustainable yield,and to translate the outputs of these models into a set ofguidelines that can be used in support of policydevelopment and ongoing planning activities. As part of afollow-up project (PATHWAYS) with the Earth ScienceSector of Natural Resources Canada, we are also in theprocess of developing an integrated modeling and decisionsupport framework for nesting these resource assessmentsin the context of regional futures scenarios being developedfor the Georgia Basin by the UBC SustainableDevelopment Research Initiative. To this end, we havebegun migrating DRASTIC-Fm and STELLA© groundwatermodels into CommunityViz,TM(Figure 8); a commercialsuite of ‘what-if’ scenario modeling and landscapevisualization tools.

The intent of the project is to leverage emerging informationtechnologies and leading edge Canadian sustainabilityresearch initiatives to promote the uptake and use of earthscience knowledge and expertise to help better addressissues of public safety (risks associated with natural hazards) and resource scarcity in the context of policydevelopment, planning and sustainable development. Thecoupling of web-based knowledge integration systems andscenario modeling tools offers an important avenue forexploring viable sustainable development strategies, andfor building coherence in policy negotiations acrossjurisdictional boundaries. Uptake and use of these tools ina planning context will help promote a wider and deeperunderstanding of environmental, social and economicissues and offers the potential for transforming the ways inwhich regional urban centers and surrounding ruralcommunities use and share information to make decisionsabout their collective future.

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Figure 7: Sustainable yield model outputs(Forster and Journeay (in prep.))

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Figure 8: Integration of the Gulf Islands intrinsic susceptibility model within a socio-economic and planning tool – CommunityViz.

REFERENCES

Allen, D.M., Abbey, D.G., Mackie, D.C., Luzitano, R., and Cleary, M. (2002). Investigation of Potential SaltwaterIntrusion Pathways in a Fractured Aquifer using anIntegrated Geophysical, Geological and GeochemicalApproach. Journal of Environmental and EngineeringGeophysics, 7(1), p. 19-36.

Aller, L., Bennet, T., Lehr, J.H. and Petty, R.J. (1987).DRASTIC: a standardized system for evaluatinggroundwater pollution potential using hydrogeologicsettings, U.S. EPA Report 600/2- 85/018.

Dakin, R.A., Farvolden, J.A., Cherry, J.A., and Fritz, P. (1983). Origin of Dissolved Solids in Groundwater of Mayne Island, British Columbia, Canada. Journal of Hydrology, 63:233-270.

Denny, S., Allen, D.M., Journeay, J.M., and Mackie, D.C.DRASTIC-Fm: A modified Vulnerability Mapping Methodfor Structurally Controlled Aquifers. (in Prep.)

Focazio, M.J., Reilly, T.E., Rupert, M.G. and Helsel, D.R., (2002). Assessing Ground-water vulnerability tocontamination: Providing scientifically defensibleinformation for decision makers. U.S. Geological SurveyCircular 1224.

Forster, C. and Journeay, J.M. . Exploring the Sustainabilityof Island Water Supplies Using Dynamic Simulation. (inprep).

Hodge, W.S. (1995). Groundwater conditions on SaltspringIsland:http://www.env.gov.bc.ca/wat/gws/gwdocs/cgds/reports/saltspring/saltspring.html#13, British Columbia Ministry ofEnvironment, Lands and Parks.

Islands Trust. How The Islands Trust Fund Plan 2003-2007.(2003) 19 June 2004. http://www.islandstrustfund.bc.ca/general/itfplan.pdf

Journeay, J.M. and Morrison, J. (1999). Field Investigationsof Cenezoic structures in the northern Cascadia forearc,

southwestern British Columbia: in Current Research,Geological Survey of Canada, Paper 1999-A, p. 239-250.

Mackie, D.C. (2000). An Integrated Structural andHydrogeologic Interpretation of the Fracture System in theUpper Cretaceous Nanaimo Group, Southern GulfIslands, BC. Unpublished M.Sc. thesis, Department ofEarth Sciences, Simon Fraser University.

Mackie, D.C., Allen, D.M., Mustard, P.S. and Journeay, M. (2001). Conceptual model for the structurally complex,bedrock-controlled groundwater flow system on thesouthern Gulf Islands, British Columbia. In: Proceedingsof the 2nd Joint CGSIAH Conference, Calgary, Alberta,Sept. 16-19, 2001.

Robinson, J.B. (1982) Energy backcasting: a proposedmethod of policy analysis. Energy Policy 10:337-345.

Ronneseth, K., Wei, M. and Gallo, M. (1995) EvaluatingMethods of Vulnerability Mapping for the Prevention ofGroundwater Contamination in British Columbia. Reportto Environment Canada.

Tansey, J., Journeay, J.M., Talwar, S., Robinson, J.,Brodaric, B. (2004). “Navigating Pathways between Policyand Science.” Horizons Vol.6 #4

Turner, Robert J.W., Franklin, R.G, Journeay, J.M, and Denny, S., (2004), Gulf Islands Waterscapes, GeologicalSurvey of Canada Miscellaneous Report.

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