Scholarly article on topic 'Enhancing water security in a rapidly developing shale gas region'

Enhancing water security in a rapidly developing shale gas region Academic research paper on "Earth and related environmental sciences"

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Abstract of research paper on Earth and related environmental sciences, author of scientific article — Shannon Holding, Diana M. Allen, Chelsea Notte, Nancy Olewiler

Abstract Study region This study is based in the rapidly developing shale gas region of Northeast British Columbia, Canada. Study focus Water security is central to decision-making within a water–energy nexus. In areas where energy resources, such as shale gas, are undergoing rapid development, water security and the associated risks to water quality and quantity are of paramount concern. However, in many regions there is a lack of understanding and data on the hydrologic system, particularly its vulnerability to hazards. The data and knowledge gap poses challenges for effective regulation of the shale gas activities and management of water resources. This paper describes initiatives that are addressing concerns surrounding water security in Northeast British Columbia. New hydrological insights for the region Initiatives and tools enhancing water security in the region include strategic partnerships and stakeholder collaborations, policy and regulation development, and data collection and distribution efforts. The contributions and limitations of each of these are discussed. A vulnerability mapping framework is presented which addresses data gaps and provides a tool for decision-making surrounding risk to water quality from various hazards. An example vulnerability assessment was conducted for wastewater transport along pipeline and trucking corridors.

Academic research paper on topic "Enhancing water security in a rapidly developing shale gas region"

Journal of Hydrology: Regional Studies xxx (2015) xxx-xxx

Contents lists available at ScienceDirect

Journal of Hydrology: Regional Studies

journal homepage: www.elsevier.com/locate/ejrh

Enhancing water security in a rapidly developing shale gas region

Shannon Holding3 *, Diana M. Allena, Chelsea Nottea,b, Nancy Olewilerb

a Department of Earth Sciences, Simon Fraser University, 8888 University Drive, Burnaby, British Columbia V5A 1S6, Canada b School of Public Policy, Simon Fraser University, 8888 University Drive, Burnaby, British Columbia V5A 1S6, Canada

ARTICLE INFO ABSTRACT

Study region: This study is based in the rapidly developing shale gas region of Northeast British Columbia, Canada.

Study focus: Water security is central to decision-making within a water-energy nexus. In areas where energy resources, such as shale gas, are undergoing rapid development, water security and the associated risks to water quality and quantity are of paramount concern. However, in many regions there is a lack of understanding and data on the hydrologic system, particularly its vulnerability to hazards. The data and knowledge gap poses challenges for effective regulation of the shale gas activities and management of water resources. This paper describes initiatives that are addressing concerns surrounding water security in Northeast British Columbia.

New hydrological insights for the region: Initiatives and tools enhancing water security in the region include strategic partnerships and stakeholder collaborations, policy and regulation development, and data collection and distribution efforts. The contributions and limitations of each of these are discussed. A vulnerability mapping framework is presented which addresses data gaps and provides a tool for decision-making surrounding risk to water quality from various hazards. An example vulnerability assessment was conducted for wastewater transport along pipeline and trucking corridors.

© 2015 Published by Elsevier B.V. This is an open access article under the CC BY-NC-ND license (http://creativecommons.org/licenses/by-nc-nd/4.0/).

Article history:

Received 24 June 2015

Received in revised form 2 September 2015

Accepted 6 September 2015

Available online xxx

Keywords: Water security Resilience

Shale gas development

Vulnerability

Wastewater

Northeast British Columbia

1. Introduction

The northeast region of the province of British Columbia (BC), Canada is estimated to hold significant unconventional natural gas reserves. Four major plays are identified in the region, with the Montney being the largest and most developed (Fig. 1). This play represents substantial commercial and economic significance to the region (Financial Post, 2014). Shale gas development in Northeast BC has occurred very rapidly following technological advancements in hydraulic fracturing and directional drilling that make unconventional sources economically feasible (Vidic et al., 2013). In the past 16 years, there has been an 82% increase in the number of shale gas development applications (BC Oil and Gas Commission (BCOGC), 1999, 2014a). In addition, estimates of the remaining reserves are increasing with marketable gas volumes projected to increase by 14% between 2015 and 2016 alone (BC Oil and Gas Commission (BCOGC), 2014a). However, the rapid development of shale gas in this region has not been matched by advances in the scientific understanding of the environmental impacts (Canadian Council of Academies, 2014). This lack of understanding poses challenges for effective regulation of shale gas

* Corresponding author. E-mail address: sholding@sfu.ca (S. Holding).

http://dx.doi.Org/10.1016/j.ejrh.2015.09.005

2214-5818/© 2015 Published by Elsevier B.V. This is an open access article under the CC BY-NC-ND license (http://creativecommons.org/licenses/by-nc-nd/4.0/).

activities alongside effective management of the environment, specifically water. Meanwhile, shale gas development is poised to continue to grow significantly in the coming years. The province of BC is committed to building a liquefied natural gas (LNG) industry under its LNG Strategy (Province of British Columbia, 2012, 2013). BC also has a vision of becoming a global leader in secure and sustainable natural gas investment, development and export, and has set a goal of having three LNG facilities in operation by 2020 (Province of British Columbia, 2015a). With such potential growth, it has become evident that an approach to policy based on historical experience with conventional oil and gas development may not be adequate for dealing with the emerging context (Goss et al., 2015).

The growth of shale gas activities in Northeast BC creates a water-energy nexus that is characterised by growing conflict surrounding water use and protection (Canadian Council of Academies, 2014). Shale gas development has the potential to significantly impact water security in the region, both through water consumption and potential contamination (Vengosh et al., 2014). Although the region is sparsely populated, water security for both human and environmental needs may be impacted. The water resources of Northeast BC require sound management in order to protect water quality and quantity in relation to the risks to water security presented by shale gas development. These risks may be minimised by strategies that build resilience (Simpson et al., 2014), such as enhancing monitoring systems, collecting baseline environmental data, strengthening enforcement capacities, preparing evidence-based regulatory requirements, and improving public engagement and transparency (Hays et al., 2015).

S. Holding et al. / Journal of Hydrology: Regional Studies xxx (2015) xxx-xxx 3

The aim of this paper is to provide an overview of the various strategies in Northeast BC that aim to build resilience. British Columbia is a relatively new player in the natural gas world, and the rapid growth in the shale gas industry presents a unique opportunity to demonstrate how the province is addressing the challenges. We begin by setting the context: reviewing industry water demands and the threats to water quality related to wastewater disposal. We then highlight activities aimed at strengthening resilience to the risks posed by shale gas activities in Northeast BC. These include strategic partnerships and stakeholder collaboration; the regulatory framework; and various water management tools including a novel groundwater vulnerability map for the Northeast BC region. We close by providing some recommendations for enhancing water security in the region.

2. Regional context

2.1. Northeast British Columbia

Northeast BC is a vast region extending from the mountains to the west, through to the foothills and low-lying flat areas to the east where the majority of the population resides and where shale gas development is focused. The climate varies from cold continental in the south to cold subarctic in the north, and is characterized by sustained cold winters and warm summers. Average monthly temperatures for November to March are below freezing. Temperatures are relatively uniform across the region, with average daily temperatures ranging between -20 °C and +17 °C (Environment Canada Climate Normals 1981-2010). Annual average precipitation ranges from 400 to 2000 mm/year, with higher precipitation rates in the mountainous western portions of the study area than in the relatively flatter eastern portions (Wang et al., 2012).

The hydrologic regime is typically snowmelt dominated, with a sustained cold winter period characterized by low river discharge and competent river ice. The spring freshet extends from approximately mid-April to late June and is characterized by high river discharge due to melting snow. After the spring freshet period, river levels generally recede slowly through the summer and autumn until the winter freeze-up. Frontal or convective storm systems bring varying amounts of rain from late spring to autumn, often resulting in increases in river levels and discharge, and occasionally producing flooding. For much of Northeast BC, there is a dearth of hydrometric measurements to directly support decision-making regarding water allocation. Groundwater information is very limited throughout the region. Until recently (see Section 3.1), few hydrogeological data were available for characterizing the shallow and deep aquifer systems. The unconsolidated aquifers, comprised of glacial or pre-glacial origin, are generally of limited extent and groundwater is often sourced from bedrock aquifers (Berardinucci and Ronneseth, 2002). Groundwater level monitoring occurs at seven provincial observation wells, three of which became active in 2012.

2.2. Water demand

Large quantities of water are required for shale gas development, particularly for hydraulic fracturing. The overall water use for an individual well depends on the length of the well and the number of times the well is stimulated (i.e., fractured) (Johnson and Johnson, 2012). As an example of water volume used for hydraulic fracturing, a well in the Montney Play requires between ~10,000-25,000 m3 water per well (Johnson and Johnson, 2012). Currently, most of the water used for hydraulic fracturing in BC derives from surface water sources, although there is increasing demand for groundwater. Shale gas withdrawals account for less than 1% of total surface water runoff estimates (BC Oil and Gas Commission (BCOGC), 2013a,b), but while water is seemingly abundant across the region, the withdrawals occur over a short timeframe and are concentrated in specific geographic locations. Mountain front watersheds deliver large quantities of water to rivers, particularly during the spring freshet; however, a large portion of the region is semi-arid and water withdrawals are increasing in these areas. The localized nature of withdrawals may lead to conflict with other water users and environmental needs, particularly during seasonal lows or drought periods (Nikot and Scanlon, 2012; Canadian Council of Academies, 2014). Moreover, surface water and groundwater are interconnected; therefore, management of the water resource becomes more challenging, especially at times of the year when streamflow is sustained by groundwater.

2.3. Water quality

A portion of the water used for the hydraulic fracturing process returns to the surface and forms a waste product termed flowback water (Gregory et al., 2011). The amount and chemical composition of flowback water depends on the type of fracturing activities, original source of water (fresh, saline, or recycled), geology, and the phase of well development (i.e., fracturing or production). Although flowback water varies in its composition, it is generally a solution with high concentrations of salts, metals, metalloids, naturally occurring radioactive materials as well as numerous proprietary chemical constituents (Goss et al., 2015). Aside from flowback water from the hydraulic fracturing process, water also returns to the surface during the production phase of a well at the same time as the shale gas or oil. This water is called produced water. Although often considered to be different types of water by industry and regulators, all flowback and produced waters are recognized as wastewater, which ultimately requires careful handling, transportation, treatment and disposal (Wilson and VanBriesen, 2012; Hladik et al., 2014). Wastewater resulting from shale gas production may be as much as ten times more

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toxic to environmental and human health than that associated with other hydrocarbon types such as conventional oil or coalbed methane due to the presence of mineral acids, dense brines and additives (Veil et al., 2004).

Recognized hazards associated with shale gas activities include spills and leakages resulting from handling, transport or disposal of the chemicals used in hydraulic fracturing or of the wastewater that is produced (Rozell and Reaven, 2012). Surface spills have a high risk of occurrence due to the large volumes handled and number of trucks used to transport wastewater to (when recycled wastewater is used for fracking) and from well pads (Mokhatab et al., 2006; Soeder et al., 2014). Remediation of spills is complex due to the large number and diverse nature of constituents which may interact differently with the hydrological system (i.e., hydrocarbons, saline water, and other chemicals may be lighter or denser than water and have soluble and insoluble components), potentially rapid infiltration rates into the soil, and long time frames needed for clean up. Gas leaks may also occur along the well annulus, through natural and anthropogenic fractures, or through abandoned/idle wells (Vidic et al., 2013). In BC, all wastewater must be disposed of in injection wells; currently, there are 112 active approved disposal wells in BC (Goss et al., 2015). Geological formations used for disposal should be contained by impermeable units and be competent to contain fluid within the area of influence of the injection well. However, there is potential for cross-connection between geological formations through natural faults and fracture zones, faulty casings in injection wells, and compromised well integrity due to aging infrastructure. In BC, proactive monitoring of penetrated shallow aquifers is recommended practice, though not required at present, and guidelines state that it is advisable to include a monitoring plan in the application for disposal wells (BC Oil and Gas Commission (BCOGC), 2014b). Potential concerns related to injection include "surface spills during injection; improper seals in old cement around well casings permitting toxic leaks into shallow aquifers; migration of water upward from deep wells to contaminate shallow groundwater" (Hume, 2014).

The potential contamination from wastewater poses a threat to communities' and First Nations' drinking water supplies and quality of life that depends on healthy aquatic ecosystems (Canadian Council of Academies, 2014). In addition, there are concerns related to the activities that accompany shale gas development such as road development, increases in vehicle traffic, landscape disruption, and air and noise pollution. Overall, shale gas development activities are associated with major industrial activities due to handling of hazardous chemicals, hazardous waste production, equipment operations and required infrastructure (Canadian Council of Academies, 2014).

3. Initiatives, regulatory framework and water management tools

3.1. Initiatives

Growth in the shale gas industry in Northeast BC has prompted the provincial government to take action on acquiring baseline information on water resources in the region. Geoscience BC was a leader in carrying out major projects aimed at collecting geoscience data. Studies include, for example, the QUEST Northwest Project, the Horn River Basin Aquifer Project, the Montney Water Project, and the PEACE Project (Geoscience BC, 2015).

More recently (since 2012), the Northeast Water Strategy (NEWS) initiative has coordinated existing water stewardship and management efforts in the region in an effort to enhance transparency and effectiveness of these efforts (Province of British Columbia, 2015b). It is headed by five departments of the provincial government related to the natural resources sector: Ministry of Agriculture; Ministry of Forests, Lands and Natural Resource Operations; Ministry of the Environment; Ministry of Energy and Mines; and Ministry of Natural Gas Development. The partnership involves many stakeholders, including local governments, regulatory agencies, First Nations groups, academic researchers, and industry representatives. The objectives of NEWS are summarised in five principal aims: (1) enhance information to support decision-making; (2) strengthen the regulatory regime; (3) coordinate and streamline the decision-making process; (4) enhance monitoring and reporting; and (5) build a water stewardship ethic. Progress so far has been focussed on the first aim, and includes sharing of data resources, gathering of new data, and preparation of information for Water Working Groups which will identify priority actions for implementation. In response to knowledge gaps related to groundwater resources in Northeast BC, the NEWS has been focusing on collecting groundwater information inclusive of baseline groundwater quality data and aquifer system characterization to supplement information on water sources and the potential for deep geological disposal sites (Geoscience BC, 2015). However, the rapid pace of development has resulted in significant challenges to acquire timely information for decision-making.

Potential challenges for the partnership include the overlapping roles of the provincial government in driving the strategy, uncertainty in the long term financial commitment from the province to support ongoing research, and support from First Nations groups. Specifically, the Fort Nelson First Nation (FNFN) has criticized the NEWS for being unclear in how the specific water policies put forward by the provincial government (vis a vis the Water Act modernization) fit with the strategy presented in the NEWS, and how the NEWS will address FNFN's issues and objectives regarding water management in FNFN territory (Fort Nelson First Nation (FNFN), 2013). These political complexities may pose an obstacle to cooperation within the partnership and among stakeholders. In addition, it will require significant effort, mandate, and capacity for the NEWS partnership to transform information and data into effective water management reforms. As shale gas development is already occurring in the region, the NEWS partnership is aimed towards supporting effective water management in the

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future. In the meantime, existing policy and regulation currently contribute to protecting water resources by addressing some of the risks related to the shale gas activities in the region.

3.2. Regulatory framework

Natural gas activities in BC are under the jurisdiction of the Ministry of Natural Gas Development (MNGD). The MNGD is tasked with developing tenure, royalty, and regulatory policy; approving investment applications; and communicating with industry, other involved ministries, major stakeholders, and First Nations. The BCOGC serves as the regulator in oversight of all permitting, regulation, and compliance within oil and gas exploration and production in the province, as per the Oil and Gas Activities Act, which, in turn, enables some specific authorities under the Environmental Management Act, as well as a number of other provincial enactments (e.g., Water Act, Forest Act).

There are two main components of the current regulatory framework. The first component governs the design, construction, operation, maintenance, reporting, prevention of incidents, and incident response. This aspect of the regulation primarily controls how shale gas activities operate, and is directed towards the prevention and remediation of contamination to the environment. Regulations are based on the Oil and Gas Activities Act and are intended to promote optimal practices that ensure safety to workers, the communities, and the environment. The regulations are generally objective-based (or goal-oriented) rather than prescriptive, which means that regulations require or prohibit certain performance outcomes in order to meet policy objectives (Hepburn, 2015). Operators are afforded flexibility in meeting objectives provided that they adhere to the specific requirements. Self-regulation mechanisms, such as pipeline integrity management programs and damage prevention programs, are also used within the regulatory framework to facilitate industry operators in meeting regulatory objectives (BC Oil and Gas Commission (BCOGC), 2015a). These programs are obligatory self-assessment tools which describe how an operator's program meets BCOGC specified performance requirements and objectives, reporting any known deficiencies, as well as a comprehensive plan and timeline for remedial action (BC Oil and Gas Commission (BCOGC), 2013b). However, the efficacy of these programs in minimizing risk is not clear due to challenges in verification, compliance and enforcement of the quality of the inspections conducted (Jeglic, 2004; Forest Practices Board, 2011).

The second component of the regulatory framework governs the protection of environmental flow needs and the water quantity required to support aquatic ecosystems. This is based on the Water Act (note that the Water Sustainability Act will replace the Water Act early in 2016 when the related regulations come into effect). A significant potential advancement in regulation falling under the new Act will be the inclusion of groundwater and management of groundwater withdrawals, which are currently unregulated. The new Act also considers the interconnected nature of surface water and groundwater, rather than treating these as separate hydrologic entities. Developing regulations under the Water Sustainability Act is a positive step in addressing this gap, and may contribute to improving resilience in the region by modernizing and expanding water management laws towards protection of water security. However, it is uncertain whether water source wells will be exempt under the Water Sustainability Act. Water source wells are wells drilled by industry to obtain water for the purpose of oil and gas development (e.g., hydraulic fracturing). The construction and operation of these wells are currently regulated under the Oil and Gas Activities Act, which requires permits from the BCOGC (and installation of monitoring wells nearby); however, the quantity of water abstracted from these wells is not regulated.

British Columbia is currently working on implementing concepts of "basin planning" or "area-based management" (Goss et al., 2015). Area-based Analysis (ABA) is a framework for managing the impacts of oil and gas development. It is an enhanced way of looking at the cumulative effects of all industrial development across the landscape when making decisions on oil and gas applications. Using ABA, "BCOGC decision-makers can assess the impact of proposed oil and gas activities on ecological, cultural and social values in the context of all other development activities. Broad landscape impacts on specific resource values can be considered when looking at specific applications or activities, rather than just the localized effects of one permit" (BC Oil and Gas Commission (BCOGC), 2013b). There is potential for ABA to improve water management in Northeast BC; however, assessment over the longer term will be essential. Given that this goal-oriented approach is relatively new, there is little information available on its relationship to best management practices (BMP) adoption by industry (Goss et al., 2015).

The shale gas industry itself has supported several initiatives that are not mandated by regulation but improve water security in the region. The largest of these is the development of water treatment plants and water resource hubs. These facilities allow produced and flowback water to be processed for use in additional shale gas activities, thus reducing the demand for fresh water abstractions at new well sites. In addition, water resource hubs are specifically designed to allow fracking fluids and flowback water to be transported through pipeline networks to limit vehicle traffic.

Overall, the design and implementation of regulatory frameworks for shale gas development is hampered across Canada by limited information and data, particularly in relation to groundwater impacts (Canadian Council of Academies, 2014). There are First Nations and other stakeholders that may have opposing views on critical issues, such as what constitutes adequate environmental flows. At a national level, the Assembly of First Nations has developed a strategy to protect and advance indigenous water rights and other local First Nations are also in discussions regarding protection and use of water resources in the region. The interpretation of the legislation and design of regulation is of particular concern to these groups given the rapid pace of development and relatively slower pace of regulation advancements.

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3.3. Water management tools

A sound scientific understanding of the hydrologic system and potential impacts of shale gas activities form the foundation of effective policy and decision-making surrounding nexus issues. The following water management tools aim to make the existing data accessible for decision-makers and stakeholders, as well as to support design of future data collection programs and initiatives.

3.3.1. Water portal

The Water Portal is a map-based water information tool that is designed to provide public access to water-related data and information. It is administered by the BC0GC(http://waterportal.geoweb.bcogc.ca/#5/55.318/-126.710).Data are linked from relevant government agencies and housed in an interactive environment where analytical tools allow the user to format the data as needed. Datasets include historical groundwater and surface water chemistry data; historical hydrographs of mean monthly depth to water from provincial observation wells; both current and historical streamflow data for major surface water bodies; and historical temperature and precipitation data collected from government and private monitoring stations. Various graphs and statistics are used to portray the data. However, the tool is limited by data availability, particularly related to groundwater. There are only seven provincial observation wells with monitored water level data in the whole Northeast BC region, and these are concentrated in one small geographic area. Groundwater data specific to shale gas development activities are not included in the Water Portal. However, geographic information system (GIS) data (industry well locations, waste disposal wells, etc.,) are available through the BCOGC website (https://www.bcogc.ca/public-zone/gis-data).

3.3.2. Northeast Water Tool

The Northeast Water Tool (NEWT) is a GIS-based hydrology decision support tool administered by the BCOGC (http://geoweb.bcogc.ca/apps/newt/newt.html). The tool combines modeled hydrometric data (e.g. monthly and annual averaged surface water flows) with water license and permitting records (Chapman et al., 2012). It is intended to provide guidance on water availability and support decision-making for new water licensing approvals. The tool is used primarily by the BCOGC in determining water allocations, although it is also open to the public. Within the map-based format, a user can access details of surface water abstraction or diversion licenses along major waterways and lakes and identify the supporting upstream watersheds. The licenses can then be compared with modelled estimates of environmental flow needs within these waterways where stressed watersheds are highlighted. The tool also generates reports on the watershed characteristics such as land cover, climate, and predicted future climate change.

NEWT was designed to overcome the poor hydrometric data coverage in the northeast by making use of available climate and land use data through a simplified water balance (runoff = precipitation - evapotranspiration). One limitation to the tool is that the modelled hydrometric data in NEWT represent long term averages rather than current conditions (Chapman et al., 2012). As inter-annual variations in hydrology are significant, the actual water availability may differ substantially year to year. In addition, the effects of climate change and resulting shifts in the hydrologic cycle are not captured, so that the tool may underestimate the implications of water withdrawals, particularly for watersheds that are already stressed. Another limitation is that the NEWT represents the reported abstractions according to permit records. It does not account for actual abstractions (which represents an enforcement issue), nor the temporal distribution of abstractions whereby large quantities may be withdrawn over short periods of time, putting increased stress on the water system. Lastly, the tool is limited by only representing the surface water system (given the simplified water balance approach), and therefore does not account for the potential influence of surface water abstractions on groundwater resources and the hydrologic balance in the region.

3.3.3. Risk-Based Water Monitoring Assessment tool

Monitoring of the hydrologic system provides vital data and allows for trends and potential impacts to be observed. However, resources for additional monitoring within Northeast BC are limited and, as a result, not all the required or desired data may be collected. The objective of the Risk-Based Water Monitoring Assessment (RBA) tool is to identify priority areas for enhancing provincial water monitoring by characterising indicators of risk to water security based on publically available datasets. The tool was developed by the provincial government in consultation with local stakeholder groups.

The RBA tool quantifies and maps the spatial distribution of risk indicators in terms of intensity, whereby every indicator is classified as high, moderate, low or not present. Surface water and groundwater are treated as separate hydrologic entities, although many of the same indicators are applied to both. There are 20 indicators for surface water; examples include forest clear cuts, surface water abstraction licenses, and anticipated irrigated agricultural growth. There are 21 groundwater indicators; examples include the presence of oil and gas wells, projected groundwater demand for shale gas activities, and existing water well productivity. The RBA tool simplifies the spatial extents based on watersheds (for surface water indicators) and map sheet units (for groundwater indicators) to result in a broad assessment of potential risks to water security in Northeast BC. The various indicators for surface water are combined to identify priority watersheds with threats to surface water quality and quantity. Similarly, the groundwater indicators identify priority map areas where there are potential threats to groundwater quality and quantity. The resulting maps are intended to provide guidance for the design of future monitoring projects. As with other data presentation tools, the RBA tool is limited by the availability of data resulting in under-representation of data sparse areas. In particular, the groundwater system is not well characterised, with poor data

S. Holding et al. / Journal of Hydrology: Regional Studies xxx (2015) xxx-xxx 7

coverage for many of the selected groundwater indicators. However, the tool is developed as a working draft that can be updated and refined as additional data are available. The RBA tool will be publically available by the end of 2015.

3.3.4. Groundwater vulnerability mapping

To specifically address the lack of groundwater information across Northeast BC, and to support the RBA tool described in the previous section, groundwater vulnerability mapping of the region has been undertaken (Holding and Allen, 2015). The intent of the mapping is to provide a broad characterisation of the vulnerability of shallow groundwater to contamination in Northeast BC. Although the vulnerability mapping presented here is limited by data availability (similar to the aforementioned data tools), the mapping method allows for inferences and interpretation to estimate aquifer characteristics in regions with poor data coverage. Recognising that increased data collection for aquifer system characterization may not be practical across such a vast region, the mapping results are an initial step in addressing these data gaps, thereby improving resilience to water security risks in the region.

Aquifer vulnerability refers to the physical characteristics of the aquifer system that make it more or less susceptible to groundwater contamination. In this study, aquifer systems represent the full range of geological materials that form aquifers (permeable units) and confining units (less permeable units). The mapping was based on the commonly used DRASTIC method (Aller et al., 1987), which has been applied to numerous hydrogeological settings in other areas of BC (Wei, 1998; Liggett and Gilchrist, 2010; Liggett and Allen, 2011) and throughout the world. DRASTIC assumes that contamination occurs from ground surface sources; therefore, the method focuses on shallow geological materials and the groundwater contained in these materials within approximately 30 m of ground surface. This method does not assess vulnerability of deeper groundwater that may be impacted from contamination originating at greater depth, but provides some indication of the relative vulnerability of shallow groundwater to sources at or just below the ground surface. Details concerning the DRASTIC approach for this study are included in the Supplementary material.

The resulting shallow groundwater vulnerability map for the region is shown in Fig. 2. Areas of higher vulnerability are shown in red with areas of lower vulnerability in green. Areas of high vulnerability occur predominantly along the mountainous western edge of the region where there is high elevation bedrock. High vulnerability is the result of generally shallow aquifers combined with high recharge rates, relatively high permeability, and limited soil cover (see Supplementary material). Other high vulnerability areas include river valleys where the vadose zone and aquifer materials have large proportions of sand and gravel. It should be noted that even in areas ranked with low vulnerability, there is still risk from shale gas development activities if chemical hazards are present. The rankings do not suggest that it is safe to operate in these areas, but rather that the aquifer is less vulnerable to land surface chemical hazards than other areas in the region.

The identification of high vulnerability areas can inform decision-makers about the greater potential for contamination of shallow groundwater system in relation to a specific hazard (i.e., the specific vulnerability). For example, the presence of a hazard related to the transport of wastewater (as represented by well site road developments and pipelines) can be overlain on the vulnerability map to produce a specific vulnerability map (Fig. 3). When considering this hazard, knowledge of the likelihood of a spill or leak is needed. At present, there is limited information on the frequency or magnitude of spills and leaks related to all transportation corridors. However, BCOGC does provide a publically accessible database on pipeline incidents that have occurred from 2000 to the present. Pipeline incidents are defined as a present or imminent event or circumstance, resulting from an oil and gas activity that is the subject of a plan that (a) is outside the scope of normal operations, and (b) may or may not be an emergency (BC Oil and Gas Commission (BCOGC), 2015b). The pipelines are not strictly used to transport wastewater, but include a number of refined and unrefined products including natural gas, sour natural gas, crude oil, water, high vapour pressure hydrocarbons, and other miscellaneous gases and oil effluent. The database currently only includes pipeline incidents, but the BCOGC anticipates future enhancements to include incidents associated with all other natural gas and oil activities (e.g., drilling and production, processing, and natural gas liquefaction).

Between 2000 and April 2015, there were 1616 pipeline incidents with spill volumes ranging from a few litres up to 20 million litres (BC Oil and Gas Commission (BCOGC), 2015c). This represents an average of 70 incidents/1000 km of existing pipelines. The hazard potential related to pipelines can then be mapped by applying this frequency to the pipeline network based on pipeline density. To illustrate the concept, a transportation corridor density map was constructed using the kernel density tool in GIS which represents the density of both roads and pipelines, combined. Given the data uncertainties, it is assumed that the likelihood of a spill of some magnitude is the same for all lengths of pipeline and road networks. The resulting shallow groundwater vulnerability to this particular hazard—i.e., a pipeline leak or road transportation spill—is shown in Fig. 4. The map was produced by combining the shallow groundwater vulnerability map with the transportation corridor density distribution (Fig. 4). High specific vulnerability represents areas with dense pipeline or road networks overlying areas with high groundwater vulnerability to contamination. The western mountainous areas have low specific vulnerability to transportation hazards due to the limited transportation infrastructure in these areas despite their higher groundwater vulnerability (see Fig. 2).

Understanding where shallow aquifers are vulnerable may inform licensing decisions, focus study sites to capture relevant data, and highlight enforcement priorities. For example, the input parameter maps generated as part of the vulnerability mapping (e.g., hydraulic conductivity) will be integrated with the RBA tool to represent aquifer properties in data-sparse areas and inform groundwater monitoring priorities. The results of the assessment form one more tool in improving resilience to water security risks from the rapidly developing shale gas sector in Northeast BC.

8 S. Holding et al. / Journal of Hydrology: Regional Studies xxx (2015) xxx-xxx

Fig. 2. Shallow groundwater vulnerability map for Northeast BC.

4. Discussion

British Columbia has experienced very rapid growth in shale gas development over the past 16 years, with an 82% increase in the number of shale gas development applications (BC Oil and Gas Commission (BCOGC), 2014a). The provincial government is committed to natural gas development, but at the same time recognizes that there are major knowledge and data gaps in the region related to water resources. This lack of understanding and data poses challenges for effective regulation of shale gas activities alongside effective management of the environment, specifically water (Council of Canadian Academies, 2014). To build a stronger knowledge base, new initiatives such as the NEWS have been established. While these initiatives represent progress, in order to effectively protect water security in the region, additional data collection is warranted. Some examples include enhanced data collection and monitoring for surface water and groundwater throughout

S. Holding et al. / Journal of Hydrology: Regional Studies xxx (2015) xxx-xxx 9

Fig. 3. Groundwater vulnerability map overlain with the pipeline network and extensive road network required for access to shale gas wells and facilities.

the region (although the region is very large); improved understanding of the interactions between surface water and groundwater, particularly with regard to impacts of surface water allocation on groundwater resources; mapping of all aquifers, particularly deep aquifers that may be in closer contact with geological units that are used for wastewater disposal. Stronger partnerships with industry may lead to more data sharing, alleviating the burden for the provincial agencies responsible for water management and protection.

The regulatory framework continues to evolve, most notably with the introduction of the Water Sustainability Act early in 2016. For the first time, groundwater will be licensed in the province, and surface water and groundwater will be recognized as a connected resource. However, groundwater abstractions for the oil and gas industry (e.g., water source wells) may not fall under the Water Sustainability Act. The BCOGC, however, has amended the water source well application process to include new requirements for hydrogeological assessment (BC Oil and Gas Commission (BCOGC), 2015d).

Several tools have been developed to support water management, but most have important and perhaps critical limitations. The tool for water allocation (North East Water Tool) does not consider groundwater, which may be a significant limitation. Therefore, some validation of this tool is needed to ensure that groundwater resources are not compromised when surface water licences are issued. The water portal, administered by the BCOGC, simply links to existing provincial monitoring, which is sorely lacking across the region. The water portal is a publicly accessible platform and with its current

10 S. Holding et al. / Journal of Hydrology: Regional Studies xxx (2015)xxx-xxx

Fig. 4. Specific groundwater vulnerability to wastewater hazards along transportation corridors.

content being limited by data availability, it likely does not raise confidence in the public that the water resources in the northeast are being adequately monitored.

Regional scale risk mapping to identify priority areas for monitoring (RBA tool) and the groundwater vulnerability mapping largely suffer from lack of detail owing to sparse data across the region. In particular, limitations of the vulnerability map relate to the generalised approach of the assessment, which represents averaged values and applies interpretations to characterise the input parameters. As a result, some local scale features and areas of concern are likely not captured. However, the maps may be updated to incorporate additional information as data availability and resolution in the region improves. Data that would be of particular benefit to improving the vulnerability assessment include additional water level data to validate the depth to water ratings, detailed aquifer mapping, characterization of aquifer parameters, and recharge measurements. Another limitation is inherent to the DRASTIC method itself — it only accounts for potential groundwater contamination from the ground surface. This means that potential contamination from below ground (e.g., from gas migration up well casings) or by lateral movement through aquifers will not be well represented. Similarly, confined aquifers are not captured because the approach only considers the uppermost geological materials. To address these specific limitations,

S. Holding et al. / Journal of Hydrology: Regional Studies xxx (2015) xxx-xxx 11

three-dimensional groundwater flow models should be developed for areas where contamination from shale gas activities are prevalent.

While regional studies offer a means to capture potential broad scale impacts to water security, small scale studies surrounding well sites or in small watersheds will enhance understanding of the localized impacts to the environment and assist design and operation regulations. Such small scale studies would provide critical detailed data, for example, on response times to contamination or the degree of connection between surface water and groundwater.

Finally, from a holistic perspective water security would be greatly enhanced by undertaking cumulative effects assessment. Such large-scale integrated hydrologic-ecological-social assessments of the region characterise the cumulative smaller-scale impacts on the water system as a whole. Area-based analysis (ABA) is a promising framework for managing the impacts of oil and gas development, but it must be grounded in science and supported by monitoring data. Industry should play a key role in providing monitoring data to support cumulative effects assessment. These recommendations will not eliminate risk, but will further build resilience as a means to strengthen water security amid the rapidly developing energy resource sector in the region.

5. Conclusions

Water security and the associated risks to water quality and quantity are of paramount concern in shale gas areas. However, in many regions there is a lack of understanding and data on the hydrologic system, particularly its vulnerability to hazards. This paper summarized initiatives, gave an overview of the regulatory framework, and highlighted several water management tools that collectively contribute to improving resilience by engaging stakeholders (e.g., communities, First Nations, government, academia), contributing knowledge, understanding risk for decision-making, and strengthening regulation and policy. These resilience building activities ultimately allow for more effective management of risks both locally and regionally within the water-energy nexus.

Acknowledgements

Funding for this research was provided by the Pacific Institute of Climate Solutions (PICS), BC Ministry of Forests, Lands, and Natural Resource Operations (BC FLNRO), the Research Institute for Humanity and Nature in Kyoto, Japan, and a Discovery Grant to Diana Allen from the Natural Sciences and Engineering Research Council of Canada (NSERC). We thank the two anonymous reviewers for their helpful comments.

Appendix A. Supplementary data

Supplementary data associated with this article can be found, in the online version, at http://dx.doi.org/10.1016/j.ejrh. 2015.09.005.

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