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Groundwater flow model of the Merritt region and potential response to coal seam dewatering Barclay, Jordin Alexander 2008

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G R O U N D W A T E R F L O W M O D E L OF T H E M E R R I T T R E G I O N A N D P O T E N T I A L R E S P O N S E TO C O A L S E A M D E W A T E R I N G by Jordin Alexander Barclay B . S c , The University of Victoria, 2002 A THESIS S U B M I T T E D IN P A R T I A L F U L F I L L M E N T OF T H E R E Q U I R E M E N T S F O R T H E D E G R E E OF M A S T E R OF S C I E N C E in T H E F A C U L T Y OF G R A D U A T E STUDIES (Geological Sciences) T H E U N I V E R S I T Y OF BRITISH C O L U M B I A July 2008 © Jordin Alexander Barclay, 2008 ABSTRACT The effects of coal bed methane ( C B M ) development on the quantity and quality of groundwater in the vicinity of the City of Merritt, British Columbia were assessed through a modeling study. The impacts of coal seam dewatering for C B M at a pilot scale and at a regional scale are assessed here using a series of groundwater flow models. Two potential pathways were identified that could hydraulically connect a dewatered coal seam and the aquifer: faults within the Tertiary rock and coal seam subcrops. A pilot scale model included coal seam subcrops along the unconformity between the Tertiary rocks and the Quaternary sediments and examined their potential response to coal seam dewatering. Using estimates of hydraulic conductivity (K) and subcrop exposure, the rate at which groundwater enters the subcrops ranges from approximately 7500 mVday for a high hydraulic conductivity scenario to approximately 70 m^/day for a low hydraulic conductivity scenario. For the medium hydraulic conductivity scenario the groundwater loss was 725 m^/day. Under a modified scenario where dewatering takes place only in relatively continuous coal seams and relatively far from subcrops, the loss was approximately 45 m^/day. The regional scale model assessed the role of a fault that extends from the southwest to the northeast through the region. For a thick, high hydraulic conductivity fault, the estimated loss was approximately 1430 m^/day whereas for a narrow, medium hydraulic conductivity fault the estimated loss was 83.2 mVday. Based on the results of this study, i f coal seam dewatering takes place in areas relatively unaffected by faults, subcrops or other potentially high hydraulic conductivity features, the risk towards the City of Merritt's groundwater supply are likely to be low. However, as the city continues to develop and the groundwater demands increase, there is inherently greater risk to the groundwater supply. TABLE OF CONTENTS Abstract i i Table of Contents i i i List of Tables iv List of Figures v I. 0 Introduction 1 2.0 Objectives 3 3.0 Physical Setting 4 4.0 Geology 7 4.1 Regional Geology 7 4.2 Merritt Aquifer 9 5.0 Coalbed Methane 13 5.1 Coalbed Methane Overview 13 5.2 Merritt Coalbed Methane 17 6.0 Water Balance 19 6.1 Coldwater River 21 6.2 Upper Nicola River and Nicola Lake 23 6.3 Lower Nicola near Merritt 24 6.4 Water Balance Modeling 26 6.5 Surface Water/Groundwater Interaction 30 7.0 Conceptual Model 31 7.1 Base Case Model 32 7.2 Pilot Scale C B M 39 7.3 Regional Scale C B M 40 8.0 Numerical Model 42 8.1 Base Case Model 42 8.1.1 Model Domain 42 8.1.2 Hydrostratigraphy 45 8.1.3 Boundary Conditions 52 8.2 Pilot Scale Model 55 8.2.1 Model Domain 55 8.2.2 Hydrostratigraphy 56 8.2.3 Boundary Conditions 59 8.3 Regional Scale Model 60 9.0 Model Results 62 9.1 Base Case Model 62 9.2 Pilot Scale Model 69 9.3 Regional Scale Model 81 10.0 Summary and Conclusions 84 II . 0 Further Work 88 12.0 References 89 Appendix A : Kala Figs and cross-sections 91 Appendix B : Hydrology Data 95 Appendix C: Chemistry Results 102 - ni - LIST OF TABLES Table 1: Table of Formations - Merritt Coalfield 7 Table 2: Annual Climate Averages 19 Table 3: Summary of Production Well Completion Data and Hydraulic Properties 46 Table 4: Base Case - Range of Values of Hydraulic Conductivity for each Layer 47 Table 5: Storage Values for Various Geologic Media 51 Table 6: Yearly pumping rates for City of Merritt Production Wells 52 Table 7: Pilot Scale Model - Range of Values of Hydraulic Conductivity for each Layer 56 Table 8: Regional Scale Model - Range of Values of Hydraulic Conductivity for each Layer 61 Table 9: Groundwater Flux from Surficial Layer into active Coal Seams 80 Table 10: Groundwater Flux from Unconformity into Fault 82 LIST OF FIGURES Figure 1: Location of the City of Merritt 5 Figure 2: Topography of Merritt 6 Figure 3: Bedrock Geology and FauU Locations 11 Figure 4: Lateral Extent of Quaternary Deposits 12 Figure 5 : Stages of Coalification 15 Figure 6: SimpUfied cross section of Merritt Basin (BC Ministry of Energy and Mines, 2003) 18 Figure 7: Locations of Hydrometric Stations Near Merritt, B C 22 Figure 8: V A D O S E / W Model Cross-section 28 Figure 9: V A D O S E / W Simulated Hydraulic Head Equipotentials 29 Figure 10: Conceptual Flow Path 36 Figure 11: Conceptual Flow Direction 36 Figure 12: Piper Plot - Coldwater River Valley 37 Figure 13: Piper Plot - Merritt Wells 38 Figure 14: Approximate Location of Lot 166 41 Figure 15: Range of Values of Hydraulic Conductivity and Permeability 48 Figure 16: Hydraulic Conductivity Configuration by Layer 50 Figure 17: Model Cross-Section through Merritt Basin 54 Figure 18: Model Plan View of Merritt Basin 54 Figure 19: Pilot Scale Model - Typical Cross-section 57 Figure 20: Pilot Scale Model - Plan View of Layer 2 58 Figure 21: Pilot Scale Model - Plan View of Layer 7 58 Figure 22: Groundwater Flow Vectors and Head Contours in Layer 1 for Base Case Model 64 Figure 23: Groundwater Particle Tracking and Head Contours in Layer 1 for Base Case Model 65 Figure 24: Groundwater Flowing in and out of Nicola River during Production Well Pumping Low Hydraulic Conductivity Scenario 66 Figure 25: Groundwater Flowing in and out of Nicola River during Production Well Pumping Medium Hydraulic Conductivity Scenario 67 Figure 26: Groundwater Flowing in and out of Nicola River during Production Well Pumping High Hydraulic Conductivity Scenario 68 Figure 28: Pilot Scale Model - Zone Budget High K Fauh 72 Figure 29: Pilot Scale Model - Zone Budget Low K Fault 73 Figure 30: Pilot Scale Model - Zone Budget High K 74 Figure 31 : Pilot Scale Model - Zone Budget Medium K 75 Figure 32: Pilot Scale Model - Zone Budget Low K 76 Figure 33: Pilot Scale Model - Zone Budget Medium hydraulic conductivity Pumping in Continuous Coal Seams Only 79 Figure 34: Groundwater Flux within Fault Zone along Unconformity 83 ACKNOWLEDGEMENTS I would like to thank Dr. Roger Beckie and Dr. Marc Bustin from the University of British Columbia for their guidance and helpful suggestions. Their time and patience in supervising this research is very much appreciated. I would also like to thanks Gary Zak and Rick Mazur for the information they provided and also the opportunity to pursue this interesting project. I would also like to thanks Brian Hobbs of Urban Systems Ltd. and Thierry Carriou of B C Groundwater Consulting Services Ltd. for their technical expertise and providing valuable information towards this research. A special thanks to the City of Merritt council, public works, the Nicola Watershed Community Round Table and the residents of Merritt. Finally, I would like to thank my friends in the U B C Hydrogroup for helping to make my time at U B C a very fun and rewarding experience. DEDICATION I would like to dedicate this research to my wife Nissa. Thank you for your patience, understanding and support. I could have never done it without you. 1.0 INTRODUCTION Coalbed methane (CBM) resources are currently being assessed by industry and government in British Columbia. C B M is a source of natural gas that is found adsorbed within coal seams. According to a document titled Coalbed Gas - Energy for Our Future, the B C Ministry of Energy and Mines estimates that B C ' s C B M resource is approximately 2.5 trillion cubic metres. C B M is produced by reducing the pressure in a coal seam and allowing the coal bed gas to separate from the coal. The coalbed gas then flows towards a pumping well where it is collected. Typically, in order to reduce the fluid pressure in a coal seam, groundwater must be extracted. The amount of groundwater that is required to be pumped from the coal seam varies depending on the permeability of the coal and the surrounding geologic media. Depending on the quality of the extracted water, it may be re-injected into isolated formations, released to the surface or used for irrigation, habitat, livestock or recreation. The City of Merritt is located approximately 270 km northeast of Vancouver in British Columbia, Canada. The city is situated near the confluence of the Coldwater River and the Nicola River. The potable drinking water for all of Merritt is currently supplied via groundwater extraction from five pumping wells. The five City of Merritt production wells are named Voght Park #1, Voght Park #2, Fairley Park, May Street, and Collettville. The groundwater that is accessed by the wells is pumped from an unconfined surficial aquifer. The B C Ministry of Environment, Water Stewardship Division classified the Merritt aquifer as one of nine type " l A " aquifers in the province of B C . A type " l A " is considered to be a heavily developed, high vulnerability aquifer. Considering the importance of safe, clean groundwater, municipal and public concern and overall awareness of their groundwater supply is high. The Merritt Coal Basin comprises several isolated areas of Eocene sedimentary rock. The main area, which covers about 80 square kilometres, is centered on the City of Merritt and includes the mining areas of Coal Gully, Coldwater H i l l and Diamond Vale. The Tertiary rocks in the area unconformably overlie the Triassic Nicola Group and Coast Range intrusive rocks. Coal was first mined in the Merritt area in the early 1900's in conjunction with the arrival of the Canadian Pacific rail line. According to JHP Coal-Ex Consulting Ltd (JHP) (2002), the highest coal production period was between 1910 and 1922 where production averaged 143,600 long tons per year. Coal mining operations continued until the 1950's. In a report issued by the B C Ministry of Energy and Mines titled Overview of the Coalbed Methane Potential of Tertiary Coalbasins in the Interior of British Columbia, (2002), the potential C B M resource in the Merritt coalfield is estimated to be approximately 52 billion cubic feet. The areas with the best potential for C B M resources are to the west and beneath the City of Merritt. Forum Developments Corp. (Forum) owns the subsurface rights within a 506 hectare area referred to as Lot 166 to the south of Merritt. The freehold title consists of rights to coal, oi l , fireclay and all mines and minerals save gold and silver (JHP, 2002). Forum is currently assessing the property for potential C B M development. As part of their assessment. Forum has funded this research to better understand the groundwater flow regime in the Merritt area and to assess the potential effects of C M B development. 2.0 OBJECTIVES This research is intended to investigate the groundwater flow regime in the Merritt area and to assess the potential hydrological efl̂ ects of coal bed methane development. In order to better understand the groundwater flow regime before and after a C B M development occurs, a conceptual hydrogeological model was formulated based on the available information. The information includes the topography of the Merritt area along with geological descriptions of the various stratigraphie units. The conceptual model also takes into account the surface hydrology including aspects of climate and the various surface water bodies in the Merritt area. The conceptual model was used to formulate a numerical model using Visual M O D F L O W version 4.0.0.126. M O D F L O W is a finite difference groundwater flow modeling software produced by Waterloo Hydrogeologic Inc. The model was first used to estimate pre-development steady-state condition, then the model was then used to simulate the current groundwater demands from the five City of Merritt pumping wells. Finally, the model was used to simulate coal seam dewatering. In total, three numerical models have been constructed. The first model is a base case scenario that defines the hydrogeological conditions of the Merritt region. The model takes into account the region's topography, geology, climate, surface hydrology and the City of Merritt production wells. The second model simulates and predicts the hydrogeologic response to pilot scale coal seam dewatering. This pilot scale model is used to assess the feasibility of coal seam dewatering and to estimate the potential groundwater flux from the surficial aquifer material into coal seams and faults in response to dewatering the coal seams. Furthermore, the results of the pilot scale model are used to infer the role of coal seam subcrops and small local scale faults at the regional scale. The third model simulates regional scale C B M development and is used to assess the role of a large regional scale fault on C B M development and regional groundwater flow. To assess the range of possible responses to coal seam dewatering, a range of plausible parameter values were used to describe the various hydrostratigraphic and structural features in each model. 3.0 PHYSICAL SETTING Merritt is located 271 km northeast of Vancouver in British Columbia, Canada (Figure 1). The city is in a valley at an elevation of approximately 595 metres above sea level (masl). The highest hills surrounding Merritt reach an elevation close to 1700 masl (Figure 2). Merritt tends to experience mild winters with little snowfall and warm, dry, sunny summers. Two major rivers converge at Merritt: the Coldwater River, which flows towards Merritt from the southwest, and the Nicola River, which flows towards Merritt from the northeast. After the confluence, the Nicola River continues away from Merritt towards the west. Nicola Lake is situated to the northeast of Merritt and is dammed at its outlet to Nicola River. Several small ephemeral creeks feed the Nicola and Coldwater Rivers. Figure 1 : Locat ion of tlie City of IVIerritt 1100000 1200CO0 1300000 1400000 1500000 1800000 Figure 2: Topography of Merritt O n 5560000- 5558000- 5556000- 5554000- 5552000- 5550000- 5548000- 5546000- Figure 2 has been removed due to copyright restrictions. The information removed illustrates the topogr^hy of the Merritt region. Information was posted on the BC" Ministry of Environment website http:// webmaps.gov.bc.ca 654000 656000 656000 660000 662000 664000 666000 668000 lôbô BC Minlstoy of En>^rorm«nt - http:/M»ps.gov.bc.c* 4.0 GEOLOGY 4.1 Regional Geology The overview of the regional geology presented in this section is based on a summary report by JHP Coal-Ex Consulting Ltd. (JHP) that was prepared for Forum in July of 2002. There are several lithologies in the Merritt area dating from the Triassic period to the Quaternary period (Table 1). Table 1 : Table of Formations - V lerritt Coalfield 1 Period Epoch Formation Lithology j Quaternaty Pleistocene & Recent stream Alluvium, Glacial Drift 1 Tertiary J Triassic Miocene of Later Valley Basalt Mainly Vesicular Basalt Miocene or Earlier Q . 2 O U) Q . O O E Volcanic Rhyolite, Andésite, Basalt witti Associated Tuffs, Breccias, and Agglomerates Tranquille Formation Conglomerate, Sandstone, Shale, and Tuff, Thin Coal Seams Coldwater Fonnation Conglomerate Sandstone, Shale and Coal Copper Creek Intrusions Granite, Granodiorite, Granite Porphyry Upper Triassic = Nicola Group Greenstone; Andésite, Basalt; Agglomerate, Breccia, Tuff; Minor Argillite, Limestone, and Conglomerate Unconformity The latest rocks in the region are the Upper Triassic Nicola Group. This group of rocks consists of predominantly volcanic rocks with minor sedimentary horizons. The volcanics consist mostly of andésite, basalt, agglomerate, breccia and tuff. The sedimentary lithologies in the Nicola Group include argillite, limestone and conglomerate. These rocks host various Tertiary granitic intrusives of the Copper Creek Intrusions. The Nicola Group underlies and surrounds sedimentary lithologies that comprise the Merritt coal field. The Nicola Group volcanics are unconformably overlain by a Lower Tertiary succession of sedimentary and volcanic units of the Kamloops Group. This Group is made up of three formations: a lower sedimentary sequence, the Coldwater Formation, a middle sedimentary - volcanoclastic sequence, the Tranquille Formation, and an upper sequence of volcanic rocks, the Kamloops Volcanics. Coal seams are present in both the Coldwater and Tranquille Formations, but those of the greatest economic potential are found within the Coldwater Formation. Up to ten coal seams may be present in the Merritt coalfield. Seven seams were measured in the Coldwater H i l l area with an aggregate thickness of 23.8 metres contained within a 258 metre section. The coal seam thickness ranged from 0.8 to 8.7 metres (JHP, 2002). Gilmar and Sharman (1981) described the stratigraphy of the Coldwater Formation as unconformably overlying the Nicola Volcanics and that the lower beds often resemble a breccia. Upwards through the coal measures interstratified sandstone predominates. Variations in thickness and lateral variations of the individual beds suggest deposition in an unstable environment. The lack of uniformity and continuity in nature and rock type greatly hinders stratigraphie correlations. The Coldwater Formation is a non-marine sequence of coal-bearing sedimentary rocks probably accumulated in a restricted inland lake environment. Coal generally grades to shale both horizontally and vertically rather than forming continuous seams. The Tranquille Formation is composed of conglomerates, sandstone, shales and tuffs with thin coal seams. The Kamloops volcanics are composed of rhyolite, andésite, and basalt with associated tuffs, breccias and agglomerates. The Merritt coal field is a Tertiary basin that was developed within part of a drowned valley system probably conforming to the present topography during the early stages of lake development (JHP, 2002). The basin is elongated N N E - S S W and measures approximately 19 km in length and 1.5 to 5 km in width. The basin is comprised of two isolated sub basins, the Nicola area, covering an area of approximately 80 km^, and the Quilchena area covering approximately 25 km^. A strike-slip fault extends from the south-west to the north-east of Merritt and is interpreted to cut through the sedimentary basin (Figure 3). The basin is overlain unconformably with Quaternary glacial, glaciofluvial, glaciolacustrine and recent fluvial deposits. In a report prepared for Imperial O i l Ltd. by Ron Swaren (1977) a geological map and a series of three cross- sections was prepared that interprets the geology across the Merritt basin and approximates the possible locations of coal seam subcrops. The report by JHP focused mostly on the area surrounding Coldwater H i l l and provides a summary of the structural geology in that area. JHP found that the geological structures trend predominantly northwest-southeast, with the main elements of the structural geology comprised of a series of anticlines and synclines and normal faults. The folded sedimentary sequence is cut by a series of northwest-southeast trending faults. These faults are interpreted as normal faults, but have been referred to as strike slip faults as well . 4.2 Merritt Aquifer In 1970 Ed Livingston described the depositional history of the Merritt aquifer. According to Livingston, at the time of melting of the last glaciers in the Merritt area the Nicola Valley was dammed, probably by ice both east and northwest of Merritt, forming a lake at least 75 metres deep at Merritt. Sediment filled meltwater from the Coldwater Valley deposited sand, silt and clay as prominently banded clays at the lake bottom. As the dams forming the lake were destroyed the lake level decreased and it finally disappeared in the Merritt area. Once the lake had gone, the Coldwater River, which was probably choked with gravel above the former lake level, cut into the soft lake beds to a level perhaps as much as 30 m below its present level. As the size of the river decreased due to depletion of ice in the mountains to the southwest, the river channel filled with clean gravel forming the gravel fan on which most of the town is built. This gravel is the aquifer supplying the town wells. According to an Aquifer Protection Plan prepared by E B A Engineering Consultants Ltd. for the City of Merritt in December of 2002, the thickness of the Merritt aquifer ranges from 5 to 50 m; however, about 80 percent of the aquifer is interpreted to be less than 10 m thick. The area that is less than 10 m thick occurs mostly on the floodplain between the Coldwater and Nicola Rivers. The deepest part of the aquifer occurs along a trough that runs sub-parallel to the Coldwater River. Most of the city production wells access this deep trough for the city water supply. Appendix A contains figures showing the locations of the City of Merritt production wells and two cross sections of the valley sediments. Figure 4 shows the lateral extent of the Quaternary deposits in the Merritt area. Currently the City of Merritt and B C Groundwater Consulting Services Ltd. are investigating the potential development of a new groundwater supply well that would operate independently from the existing production wells. The siting of the possible production well is within a deeper aquifer system. The deep aquifer system is thought to be confined by the overlying glaciolacustrine silt (Kala, 2004); however, it remains undetermined i f this deep aquifer is hydraulically connected to the surficial aquifer and/or the surface hydrology by relatively permeable materials. For the purpose of this thesis the presence of the deep aquifer is not considered and potential development of a new groundwater supply well within the deep aquifer is not explored. Figure 3: Bedrock Geology and Fault Locations Figure 3 has been removed due to copyright restrictions. The information removed illustrates the topography of the bedrock geology and fauh locations in the Merritt region. Information was posted on the BC Ministry of Energy, Mines and Petroleum Resources website http://webmap.em.gov.bc.ca/mapplace/minpot/bcgs.cfm SCALE 1 : 105.859 2 W L E S Geology from BC Ministry of Energy and Mines Figure 4: Lateral Extent of Quaternary Deposits 5560000- 5558000- Figure 4 has been removed due to copyright restrictions. ITie information removed illustrates the topography of the Merritt region and the ©ctents of the Quaternary Deposits, infomiation wa.s posted on the BC Mini.stry of Environment website http:/.' webma[».gov.bc.ca 5552D00- 5550000- 5548000- 5546000- 654000 656000 6S8000 660000 662000 664000 666000 668000 Yeibw area rapreserts Quaternary gaoJogy o Color hWstiade and Quatomary Extern fiom BC Mlnistiy of Environmort • M^://niap&gov.bcca/ 5.0 COALBED METHANE 5.1 Coalbed Methane Overview The interior of British Columbia contains a number of fault bounded Tertiary basins that contain coal (BC Ministry of Energy and Mines, 2002). Among these Tertiary basins is the Merritt Coal Field. Under the appropriate conditions coal can act as a source, a reservoir and a trap for significant quantities of methane and minor amounts of other gases (Bustin and Clarkson, 1998). C B M is retained in coal in a number of ways including: adsorbed molecules within micropores; trapped gas within matrix porosity; free gas in cleat and fractures; and as a solute in groundwater within coal fractures (Bustin and Clarkson, 1998). C B M is formed in the coal by either biogenic or thermogenic processes. If the coalbed is buried deeply, so that there is sufficient hydrostatic pressure, the methane wi l l remain adsorbed on cleat surfaces and in micropores in coal. The gas is held in place by weak attractive forces between the coal and the gas and by hydrostatic pressure from groundwater in the coal. Gas migration by desorption, diffusion, and free-phase flow takes place when the pressures in the coalbeds are decreased, which can take place either naturally or by human activities (Rice, 1993). Human activities that can reduce the pressure in a coalbed include coal mining or gas production from wells. Because most coals are characterized by high water saturations, depressurization results from dewatering of the coal seam (Rice, 1993). To produce the gas, water is pumped from wells completed in the coal seam, the hydrostatic pressure is reduced, and the gas is desorbed. The gas and water move to the well as a two-phase fluid. The water enters the pump and is discharged through the water line and the gas flows up the well casing to be extracted by a low-pressure compressor. Natural gas is generated in coalbeds throughout their burial history. The gas can be generated during three stages: (1) early biogenic gas, formed by bacteria in the early stages of coalification; (2) thermogenic gas, formed by thermal processes during the main stages of coalification; and (3) late stage biogenic gas, which can form in coals of any rank i f the right conditions are met for methane producing bacteria to flourish (Johnson and Flores, 1998). Early biogenic gas is generated by the degradation of the organic matter in coal at shallow depths and low temperatures in rapidly accumulating sediments during early stages of coalification and at low ranks (Rice, 1993). Typically, methane generation occurs i f the temperature is less than 75°C, the environment is anoxic with low sulphate concentrations and adequate pore space exists (Johnson and Flores, 1998). Two pathways have been identified for early methane generation in coals: carbon dioxide reduction and methyl-type fermentation (Rice, 1993). Most biogenic methane found today is the result of carbon dioxide reduction (Johnson and Flores, 1998). With the increased temperatures and pressures that occur during subsidence and burial of a coalbed, coal becomes enriched in carbon as large amounts of volatile matter rich in hydrogen and oxygen are released (Rice, 1993). The onset of thermally generated hydrocarbon gases begins at coal ranks near the high volatile bituminous reflectance of 0.6% (Figure 5) (Johnson and Flores, 1998). If the coal seams are later uplifted and the temperature and pressure drop, late stage biogenic gas may be produced. Methane generating bacteria can be reintroduced into the coalbed via transport with groundwater. Cleat apertures tend to dilate as the pressure of overburden is reduced, which facilitates the flow of groundwater into the coalbed (Johnson and Flores, 1998). Conversely, flow of groundwater through a coal seam can deplete the coal of methane, as methane desorbs to equilibrate with the water. Kaiser et al. (1994) found that C B M producibility is determined by six controls: coal distribution, coal rank, gas content, permeability, groundwater flow, and depositional and structural setting. Peat accumulation and preservation as coal requires a balanced subsidence rate that maintains optimum water table levels but excludes disruptive clastic sediment influx. The depositional systems define the substrate upon which peat growth is initiated, and ultimately enables prediction of coalbed thickness, geometry, and continuity. Traditionally, thermally generated gas content has been correlated to coal rank, however; gas content cannot be determined by coal rank alone. Greater burial depths raise reservoir pressures and increase the methane adsorption capacity of the coal. Figure 5: Stages of coalification and common properties of measurement (Rice 1993). d.a.f=dry and ash free. R a n k F M . V o l . M % C i f t e n Vi l r i i a S a d M o u b j r a C d . V a t v a . US P e a t • 0 3 - m —a* - • 0 - e a . « o - c a T S — s s - Œ . 36 - 7 » 0 - 0 4 — 52 — a — « . 7 1 - 9 W 0 • X - as • OA — 4« — OU 77 - 13600 ^ 1 - 9.7 - OM — 40 ' I - » - 32 - - M — » « 7 — ISSOO B k u m i n o M - 1 4 — 24 L o w V o i a t i * - 1 * — ZO B i m n i n o u s - \M — i « S m « h — 12 * - e a - W — tSSOO • - 3.0 - 4j0 — 4 Furthermore, Bustin and Clarkson (1998) found that there were no consistent trends in methane adsorption capacity with composition or rank of coals. Gas content of coals can also be enhanced, either locally or regionally, by generation of late stage biogenic gases or by diffusion and long-distance migration of gases to no-flow boundaries such as structural hinge lines or faults for eventual re-adsorption and conventional gas trapping. Gas migration requires laterally extensive, permeable coals and dynamic groundwater flow. Permeability of a coalbed is determined by its fracture (cleat) system, which is in turn largely controlled by the tectonic/structural regime. The cleat system is the primary avenue for gas and water flow during gas production; however, the majority of gas (up to 95%) resides in the coal matrix (Cui et al, 2003). Consequently the producibility of a coal seam is not only dependent on the permeability of the coalbed, but also the rate of gas diffusion within the coal matrix. Coal seams can act as conduits for gas migration, but also commonly act as aquifers with permeabilities that are orders of magnitude larger the surrounding sedimentary strata. Although high permeability can result in high producibility of gas, permeability that is too high can result in high water production. High water production may be detrimental to the economic production of coalbed methane i f the water is of poor quality compared to the regulatory standards since it would require treatment and/or disposal according to applicable federal and/or provincial regulations. Furthermore, i f a coal seam is developed for C B M , and production of water is high, the surrounding aquifers may be affected. If there is connection between a coal seam and an aquifer via a relatively high permeability pathway, removal of groundwater from the coal seam may result in depletion of the aquifer. McKee and Bumb (1987) identified that i f the hydrostatic pressure in the coal seam is significantly higher than the desorption pressure, gas production may follow three stages from a coal bed methane reservoir. During the first stage, a water-saturated coalbed methane well produced and commonly encounters only single-phase or water saturated flow. During the second stage the reservoir pressure continues to be reduced and methane gas begins to form as the result of desorption from the coal. As methane gas forms, some of the pathways which were originally saturated with water become blocked by gas bubbles. B y blocking water flow pathways the relative permeability of the formation to water is reduced. However, during the second stage, the gas does not yet flow because the bubbles are not connected within the porous coal matrix nor in the cleat or natural fracture system of the coalbed. The second stage is characterized by the presence of two phases, gas and water, however only the water phase is mobile. The third stage is reached as the reservoir pressure decreases and additional gas is desorbed. The gas saturation builds until the gas bubbles connect and form a continuous pathway to the producing well. Two-phase flow begins at the point where the relative permeability to gas becomes non-zero. A s the reservoir pressure is further reduced and additional gas is desorbed, the relative permeability to gas increases and the relative permeability to water decreases. If the initial water pressure is not higher than the pressure at which gas begins to desorb the water saturated flow stage and possibly the unsaturated flow stage could be absent (McKee and Bumb, 1987). Due to the many factors that determine the producibility of a coal seam, it is very difficult to predict how a coal seam wil l respond to gas production. There is significant interplay between the factors listed above which taken together determine i f C B M production is feasible or not feasible. 5.2 Merritt Coalbed Methane Based on the regional geology of the Merritt area, and considering the complex interplay between factors that influence C B M producibility, the C B M potential in the Merritt area is difficult to estimate. A description of the depositional history of the sedimentary geology was provided by Gilmar and Sharman (1981) and is included in section 4.1. The rank of the coal spans the range from high-volatile bituminous C to A . No tests for methane content have been conducted (JHP, 2002). The Tertiary units are described to have been deposited in a non-marine sequence that likely accumulated in a restricted inland lake environment. The continuity of the coalbeds is further compromised by the folding and faulting in the area. Figure 6 shows a simplified cross section of the Merritt basin along a plane extending from the southwest to the northeast of Merritt. The folding and faulting in the region is most intense to the southwest, where a series of anticlines and synclines are observed. Moving to the northeast, the sedimentary basin appears to follow a broad shallow syncline. The majority of the anticline structure in the Coldwater Hi l l area is eroded so that coal seams subcrop along an unconformity near the southwest margins of the sedimentary basin. The coal seam subcrops may allow hydraulic connectivity between the near surface hydrology and the individual coal seams. Hydraulic connectivity has potential to decrease the producibility of C B M i f groundwater flow is sufficient to strip the coal of methane. Furthermore, if C B M development were to take place, the Quaternary sediments above the unconformity may provide a constant source of water to the coal seam and dewatering may not be feasible. In this scenario, the permeability provides the greatest source of uncertainty when determining i f the coal seam can be dewatered. In general the permeability of the coals and surrounding geological units are poorly understood. Although it is assumed that the units surrounding the coalbeds (mostly sandstone/shale) are of lower permeability than the coals, to date, this assumption has not been verified by field measurements. The Merritt basin's potential for C B M development is poorly understood. Further investigation in the area would improve the understanding of the continuity of the coal seams, the gas content in the coals and the role of groundwater flow within the system. O f particular relevance to the groundwater flow system is the role of faults and subcrops and better constraints for the permeabilities. Figure 6: Simplified cross section of Merritt Basin (BC Ministry of Energy and Mines, 2003) Coal Gulley Mines PLEISTOCENE ' Unconsoliclaiecl Sediments MID^OCENE Princeton Group Sedirnents TRIASSIC I ' Nicola Group Votearacs Coal Seams 1000 —( 6.0 W A T E R BALANCE The hydrologie system at the ground surface represents the sources and sinks for the groundwater flow system. The major source of water to groundwater is recharge from precipitation. Precipitation varies annually, seasonally, and geographically, but for the purpose of this project, the annual rainfall in the Merritt area is assumed to be approximately 322 mm/yr (Table 2). Other sources of water to groundwater include: seepage from streams, rivers and lakes, and discharge from anthropogenic sources. Water can be removed from the surface hydrologie system via discharge from steams and rivers, évapotranspiration, sublimation, removal for anthropogenic uses, and recharge to groundwater. Table 2: Annual Climate Averages Month Evapotranspiration (mm) Precipitation (mm) Deficit (mm) January 15.5 37.2 21,7 February 31.9 23.6 -8.3 March 58.9 16.6 -42.3 April 102.0 14.5 -87.5 May 148.8 26.8 -122.0 June 132.0 34.1 -97.9 July 161.2 25.8 -135.4 August 155.0 22.1 -132.9 September 87.0 23.6 -63.4 October 46.5 23.5 -23.0 November 21.0 34.7 13.7 December 15.5 39.6 24.1 Sum 975.3 322.1 -653.2 ET data collected from Farmwest: http://www.farmwest.com from the Kamloops Airport Station Precip data collected from www.climate.weatheroffice.ec.gc.ca/climate_normals Environment Canada operates three hydrometric stations in the Merritt area, one on Coldwater River (station ID 08LG010), one at the outlet of Nicola Lake (station ID 08LG065) and one approximately 6.5 km to the northwest of the confluence of the Coldwater River and the Nicola River (station ID 08LG007). These three hydrometric stations are shown on Figure 7. Six additional hydrometric stations are located in the Merritt area, three to the north of Merritt and three to the south of Merritt. The three stations to the north of Merritt are located outside of the drainage area for this study's region of interest and therefore are not considered for the remainder of this report. The three stations to the south of Merritt lie within the drainage area of the Coldwater River catchment and are ephemeral with low peak flows compared to the peak flows of the Coldwater River. Therefore, the hydrometric stations south of Merritt are not considered for the remainder of this report. Historical hydrometric data from Canada's H Y D A T database for the three hydrometric stations shown in Figure 7 was used to formulate a water balance for the Merritt region. The water balance also uses data collected from the B C Ministry of Environment, Water Stewardship Division for water license permits. Only active permits are considered when calculating the maximum amount of surface water that is permitted for use by the B C Ministry of Environment. There are several uses for the permitted water including irrigation, domestic use, stock watering, and industrial. Historical hydrometric data and details of the water licenses are included in Appendix B . There are several groundwater wells that were identified using the B C Ministry of Environment Water Resources Atlas, mostly located in valleys. Volumes of groundwater extraction from these wells are unknown as groundwater wells in British Columbia are not regulated. In order to accurately approximate a water balance for the Merritt area, several additional factors must be considered that are not directly addressed as part of this study. A major factor is the contribution of snowmelt to surface runoff during the spring freshet. It is expected that snowmelt during spring contributes the majority of surface runoff in the Merritt basin. The volume of runoff due to snowmelt depends on how much snow accumulated over the winter and the rate of sublimation. Furthermore, the amount of surface runoff during snowmelt and during periods of heavy precipitation depends, in part, on the capacity of the soil to allow infiltration. Other considerations include the volume of water that is able to flow along valley basins as baseflow. The water balance formulated in the following sections use average streamflow values and does not take into account the above factors. It is expected that these fluctuations in the surface hydrology would not affect the groundwater flow system, especially at the depth of coal seam dewatering. Considering that the above listed factors are dependant on natural processes, it is prudent to measure streamflow on unregulated water courses. Unfortunately, the three hydrometric stations considered in this hydrological summary record flow measurements from regulated water courses. When determining a water balance, streamflows measured from regulated water courses may introduce additional uncertainties. Water may be retained upstream of hydrometric stations on regulated streams. The retained water may be for human uses or for storage. Another result of surface water retention is that there is additional water available for évapotranspiration, especially during the summer months. It is likely that more water is removed from the hydrological system along regulated streams than along unregulated streams. 6.1 Coldwater River The gross drainage area for the hydrometric station at Coldwater River is approximately 914 km^ and extends from its origin near the Coquihala toll booth up to the confluence with the Nicola River. According to the Environment Canada Water Survey, at its confluence with the Nicola River, the mean discharge of the Coldwater River is approximately 8.21 mVs. Kala (2004) determined average low annual flow in the Coldwater River to be approximately 1 m^/s; however, flows have been recorded to be as low as 0.1 mVs. Using an annual rainfall of 322 mm/yr, the drainage area receives approximately 9.32 m^/s of recharge to the surface. Based on these calculations approximately 88 percent of surficial recharge in the Coldwater River watershed is discharged as stream flow. In a semi-arid region such as Merritt, a high proportion of stream flow to area and precipitation is not expected. A n additional climate station is located near Brookmere, approximately half way between the Coquihala toll boot and Merritt. The average precipitation at this station (climate ID 1121090) is 564 mm/yr. Based on this average precipitation there is a large precipitation gradient with elevation moving towards the headwaters of the Coldwater River. With a precipitation of 564 mm/yr, approximately 50 percent of surface recharge discharges as streamflow. Figure 7: Locations of Hydrometric Stattons Near Merritt Figure 7 has been removed due to cof^right restrictions. The information removed illustrates the river and stream network in the .Merritt region and the locations of nearby hydrometric stations. Information posted on the BC Ministry of Envircmment website http://webmaps.gov.bc.ca Color Hilahade from BC Ministty of Environment - http-7/maps.gow.bc.ca' iMm Although there are not any additional climate stations up the Coldwater River valley, it is plausible that precipitation wi l l continue to increase with increasing elevation. Based on observations of the climate regime near Merritt it appears as i f the area near the upper Coldwater River receives the most precipitation within the Coldwater River and Nicola River watersheds. The precipitation that is not accounted for in the streamflow measurements can be explained by water withdrawals and evaporation. Currently there are twenty-six active permits allowing use of water from Coldwater River. From the twenty-six active permits, water is removed from the Coldwater River at a rate of approximately 0.23 m^/s. The amount of water permitted for human use accounts for 2.5 percent of the water loss in the system. The remaining water is likely removed from the system via évapotranspiration (ET). Table 2 shows the average E T is greater than the average rainfall in nine months of the year. The potential évapotranspiration rates depend upon the temperature, intensity of solar radiation, the vapour pressure, and wind speed as well as the land use type. Actual evaporation rates depend on the factors listed above, but are largely constrained by the amount of water that is available at or near the ground surface. Due to the large difference in precipitation with elevation and location within the Coldwater River watershed, it is difficult to estimate the water loss due to ET; however it is likely greater than 50 percent of the total precipitation. 6.2 Upper Nicola River and Nicola Lake The gross drainage area for the hydrometric station located at the outlet of Nicola Lake is 2990 km^ and extends to the northeast from Nicola Lake. Nicola Lake is dammed at its outlet and according to the Environment Canada Water Survey the mean discharge directly after the dam is 5.12 mVs. Based on an annual rainfall of 322 mm/yr, the drainage area receives approximately 30.5 m^/s of recharge to the ground surface. Based on these calculations, approximately 16.8 percent of the surface recharge to the Nicola River watershed is discharged at the outlet of Nicola Lake. According to the B C Ministry of Environment, Water Stewardship Division there are thirty-six active water licenses permitting use of water from the Upper Nicola River and Nicola Lake. From the thirty- six active permits, water is removed from the Nicola River and Nicola Lake at a rate of approximately 0.53 m^/s. Furthermore, Fisheries and Oceans Canada and Ministry of Environment Water Right Branch own the rights to very large amounts of water from Nicola Lake. The permits are for storage and conservation purposes. The stored water is used only during drought to maintain a healthy water level in the river for aquatic life and is rarely released (per conversation with Fisheries and Oceans Canada). The amount of water permitted for human use accounts for 1.75 percent of the water loss in the system. The majority of surface recharge, approximately 81.5 percent, is likely removed from the system via E T and discharge into the groundwater system. The difference between the loss from the Nicola drainage area and the Coldwater drainage area may be due to the amount of available water at the ground surface and the residence time of surface water in each drainage area. Surface water for the Coldwater drainage area flows into the Coldwater River from a relatively narrow catchment and is then transported relatively quickly via the Coldwater River. Since the residence time for water in the Coldwater drainage area is relatively short and the water available for ET is relatively low, the effects of water loss are less pronounced. Conversely, surface water for the Nicola drainage area flows into Nicola Lake where there is a large amount of water available for E T for the entire year. For the purpose of this study, the hydrology of the upper Nicola is not considered further, as the limits of the region of interest do not extend beyond Nicola Lake. 6.3 Lower Nicola near Merritt The gross drainage area for the hydrometric station located approximately 6.5 km to the northwest of the confluence of the Coldwater and Nicola rivers is approximately 4350 km^. According to the Environment Canada Water Survey, the mean average discharge at this station is 13.9 mVs. Kala (2004) determined average low annual flow in the Nicola River to be approximately 5 m^/s; however, flows as low as 1 mVs have been recorded. Based on an annual rainfall of 322 mm/yr, the drainage area receives approximately 44.4 m^/s of recharge to the ground surface. Based on these calculations. 31.3 percent of the surface recharge to the drainage area is discharged at the location of this station. The drainage area of the lower Nicola River is approximately 446 km^, subtracting the area of the upper Nicola River and the Coldwater River. Based on the size of this drainage area, the annual recharge to the ground surface due to precipitation would be 4.55 mVs. The sum of the mean discharge at stations 08LG010 and 08LG065 is 13.33 mVs. Therefore, the total volume added to the area is 17.88 mVs. Another possible source of water added to this area is from the City of Merritt wastewater treatment plant. According to the City of Merritt Public Works and the City of Merritt wastewater plant, wastewater is discharged at a rate of approximately 0.04 m^/s. The wastewater is discharged to rapid infiltration basins and emergency overflow discharge to the river happens during flood conditions and only twice in the past ten years. The infiltration basins are located along the Coldwater River near the west side of Merritt. Based on this information, it is unlikely that the wastewater plant is a significant source of water to the surface hydrology. Based on a total of 17.88 m^/s added to the catchment and a total discharge of 13.9 mVs at station 08LG007, approximately 77.7 percent of the surface water is discharged. The B C Ministry of Environment, Water Stewardship Division reports that there are thirty active water licenses permitting use of water from the Merritt area of the Nicola River. From the thirty active permits, water is removed from the Nicola River at a rate of approximately 0.14 mVs. The amount of water permitted for human use accounts for 0.78 percent of the water removed from the system. The remaining 21.5 percent of the water removed from the system is likely lost due to ET and recharge to the groundwater system. It is important to note that station 08LG007 is located within the basin of Nicola watershed. To the west of Merritt, the valley and likely the aquifer narrows, therefore groundwater likely discharges to surface water at a higher rate near station 08LG007 than at stations 08LG010 and 08LG065 (more explanation in section 7). A s such, the discharge rate measured at station 08LG007 may be overestimated i f accounting for surface water contributions alone. A n additional loss of surface recharge includes recharge to the groundwater flow system. Groundwater within the drainage area may eventually be discharged to stream flow. As such, i f the system is at steady state, any loss of surface water to groundwater may coincide with a gain from groundwater discharging to surface water. The low flow values provided by Kala (2004) for the Coldwater River are approximately 1 m^/s for the Coldwater River and 5 m^/s for the Nicola River. It is expected that the streamflow during low flow conditions (typically end of March, prior to snow melt) is largely dependant on groundwater discharge. The values estimated by Kala represent 11.3 percent and 10.7 percent of recharge to the Coldwater and Nicola catchments, respectively. Thus, at steady state, the groundwater recharge from precipitation likely represents approximately 11 percent of the total precipitation. The total water balance for the Merritt region is difficult to estimate due to the wide range of possible E T values. Nevertheless, perhaps a reasonable estimate would be approximately 70 percent of the precipitation is removed from the catchment via sublimation and évapotranspiration, 20 percent of the precipitation results in surface runoff directly to streamflow (mostly during snowmelt) and 10 percent of the precipitation recharges the groundwater system. 6.4 Water Balance Modeling Due to the relatively wide range of possible évapotranspiration, runoff and groundwater recharge values V A D O S E / W was used to refine the estimate of groundwater recharge. V A D O S E / W is a two dimensional finite element modeling software used for analyzing flow from climate inputs, across the ground surface, through the unsaturated vadose zone and into the groundwater system. The modeling software accounts for potential and actual évapotranspiration as a function of soil water pressure, snow accumulation and melt, plant transpiration, surface seepage, runoff and ponding, and groundwater recharge. The two dimensional model section was interpreted from a series of cross-sections (JHP, 2002) that trend southwest to northeast from Coldwater H i l l to Coldwater River. Figure 8 illustrates a cross section of the materials modelled in the V A D O S E / W simulation. Several parameters must be entered into a V A D O S E / W model including: a hydraulic conductivity function and a volumetric water content function for each material type, a plant moisture limiting function, a root depth function, a leaf area index function, thermal conductivity and volumetric specific heat, and daily precipitation, wind, relative humidity and temperature. Field data regarding each of the functions listed above, aside from climate data, have not been measured. As such, functions were chosen from a series of typical functions provided with the V A D O S E / W software. Daily climate data was collected from Environment Canada online climate data at the Merritt STP station (ID 1125079). In general, the simulated hydraulic head was a subdued reflection of topography. Figure 9 illustrates the head equipotentials simulated in the V A D O S E / W model. The surficial layers were modeled as sand and gravel or colluvial material. As such, the majority of groundwater flow was simulated as flow within the surficial layer. Groundwater recharged on the hill slopes and discharged along the valley bottom. However, during summer when évapotranspiration rates are high, the groundwater flow direction reversed from towards Coldwater River to away from Coldwater River. To estimate groundwater recharge into the surficial layer a series of flux sections were introduced. A flux section is a section of the model that can be specified for model output. Since the highlands and hil l slopes make up the majority of the area in the area of interest, the flux sections that were used to collect output recharge values from the V A D O S E / W model were specified along a hill slope. The groundwater recharge varied significantly over the course of a year, where high recharge was observed during spring freshet and late fall and very low recharge was observed during summer when évapotranspiration is high. At some times, the infiltration was calculated as a negative value. This indicates that évapotranspiration exceeds precipitation to the point that negative pressures are simulated in the surficial layer causing a net upwards flux of vapour flow. Using a yearly average for recharge the V A D O S E / W model simulated that approximately 6 percent of the annual precipitation infiltrates into the groundwater flow system. Based on the estimates of recharge presented in this water balance section, the groundwater recharge for the area of interest is approximately 6 to 10 percent.  Distance (X 1000) Meters 6.5 Surface Water/Groundwater Interaction B C Groundwater Consulting Services Ltd. (BC Groundwater) prepared a Surface Water/Groundwater Interaction Study for the City of Merritt in March, 2006. B C Groundwater concluded that groundwater recharge to the Merritt aquifer originates from the catchment areas to the north, east and south of Merritt and also from precipitation within the city limits. Groundwater from the north and northeast flows beneath and into the Nicola River, while groundwater recharge from the south flows beneath the Coldwater River. The main contributor to the surficial aquifer recharge is leakage from the Nicola River, with limited leakage from the Coldwater River. Coldwater River may be limited to surface water flow and the river may become disconnected from the water table during certain periods of the year. 7.0 CONCEPTUAL M O D E L To better understand the groundwater flow dynamics and create a predictive tool to understand how the flow system near Merritt wi l l behave in the future, a numerical groundwater flow model was constructed. To construct the numerical model for the Merritt region a conceptual model is required to define the most important aspects of the flow characteristics of the system. The conceptual model of a flow system is the foundation upon which the model is constructed. The accuracy of the conceptual model cannot be tested until the numerical model is constructed and the results are compared to field observations of the real system. This allows the modeller to assess the conceptual model and make appropriate changes. It also guides future data collection that can be used to produce a conceptual model that is more consistent with field observations. Thus, formulating a conceptual model is an iterative process where it may be continuously updated. For the Merritt region, a challenging scenario is presented. Very little information about the hydrogeological conditions for the region is available and there is little information to compare the conceptual model with field observations. Accordingly, the initial conceptual model is simplified and contains several subjective interpretations. Furthermore, the conceptual model cannot be reassessed upon reviewing the numerical model results since relevant field data does not exist to date. This study therefore employs a range of estimates for key parameters to develop the conceptual model and subsequent numerical models. Although little hydrogeological information was available, several other sources of information were considered when creating the conceptual model. These sources of information included: • Previous reports published such as Swaren (1977), E B A (2002), JHP (2002), Kala (2004), B C Groundwater Consulting Services (2006) and Westwater Mining (2003); • Conversations with members of the Merritt community, Urban Systems Ltd., B C Groundwater Consulting Services Ltd., and government representatives; and, • Several site visits to familiarize with the study area, collect groundwater samples from available wells and springs, and observe some of the surficial sediments. In order to accomplish the objectives of this study, three different numerical models were created. The first model, a base case scenario, was constructed to represent the topography of the Merritt region, the geometry of the various geological units, aspects of the surface hydrology and the current City of Merritt production wells. A second model was constructed to assess the potential response to coal seam dewatering at a pilot scale. This model is used to investigate the role that faults and coal bed subcrops play on the groundwater flow in response to coal seam dewatering in the area of Coldwater H i l l to the south of Merritt. The third model is used to investigate the potential effects on groundwater flow at a regional scale and includes the role of a major fault on the hydrogeologic response to C B M development. Due to a lack of hydrostratigraphic information, for each of the three scenarios a sensitivity analysis was performed to assess the hydrologie response to a wide range of plausible parameter values. The hydrostratigraphic configurations employed in these conceptual models were very simple. The conceptual models were designed to maintain the essential features of the geology and flow regime of the system, yet allowed for flexibility and numerical stability in the models. This flexibility allowed the models to be conceptually accurate while, given the software limitations, ensured that the numerical models would converge and produce reasonable results. 7.1 Base Case Model In the Merritt region there are several distinct hydrogeological layers. The main geological formations are Triassic volcanics overlain by Tertiary sedimentary units overlain, in part, by Quaternary sediments. For the base case model the objectives were to reproduce the current groundwater flow system in the Merritt region, and in particular, simulate the City of Merritt production wells at a regional scale. Detailed information about the properties of the Triassic volcanics and the Tertiary sediments are not as pertinent to the base case model as the information regarding the Quaternary sediments since the production wells are completed in the surficial Quaternary aquifer. The information provided in section 4.2 suggests that the sedimentary units do not extend through the entire region, and they are completely surrounded by the Tertiary volcanics. At some depth below the sedimentary units and/or the surface, the volcanics are likely to have a very low hydraulic conductivity and behave as a barrier to groundwater flow, or a no-flow boundary. To date, there is no physical evidence to support or invalidate this assumption of a no-flow boundary. Between the sedimentary units and/or the surface and the no-flow boundary a relatively gradual change in hydraulic conductivity is assumed as the volcanics grade from relatively weathered and/or fractured rock to stable un- weathered bedrock. The thickness of the weathered material is not known, however, it is considered to be significant since the region has undergone folding, faulting, glacial weathering and post glacial uplift. Conceptually, the weathered volcanic rock appears like a shell beneath the surface and/or sedimentary units with hydraulic conductivity grading from high to low with increasing depth. Due to limitations in the software, the geometry of the Tertiary sedimentary units was simplified. There are six major coal seams that extend across the sedimentary basin. The configuration of the sedimentary units is complex and there are folds and faults causing the various strata to become laterally discontinuous and, in some cases, outcrop to the surface. Ideally, these six coal seams would be represented in the numerical model; however, due to constraints with the software (discussed in section 8.1), the use of six relatively thin coal seams is not feasible. Consequently, the six coal seams are simplified into two coal bearing units with uniform thickness which still reflect the undulating surfaces of the folded and faulted units. The Quaternary sediments are made up of glaciolacustrine silts underlying alluvially deposited gravel and sand. The presence of the glaciolacustrine silts was determined from previous drilling; however, the depth and extent of the silts is poorly defined. The depth of the silts is inferred in a pair of cross sections prepared by Kala (2004) (Appendix A ) in the area directly beneath Merritt. The silts are assumed to underlie the alluvial gravel and sand throughout the region. However, since the city of Merritt is situated over the pre- historic ice dammed lake described in the section 4.2, the thickness of the silts may decrease with distance from Merritt and the glaciolacustrine basin. The alluvial gravel and sand deposits are relatively well defined. The B C Ministry of Environment Water Resources Atlas displays online information related to the water resources of the Province of British Columbia, such as watersheds, water quantity and quality monitoring sites, aquifers, water wells and flood protection works. Several water wells were found in the Merritt area and borehole logs were available for some of these wells. From the borehole logs the bottom of the alluvium was determined in several locations. Also, the two cross sections prepared by Kala (2004) (Appendix A ) were used to determine the bottom of the alluvium beneath the city of Merritt. The extent of the Quaternary deposits is shown on Figure 4. Conceptually, the Quaternary deposits appear like a trough in the Nicola and Coldwater valleys. Furthermore, the alluvial gravel and sand forms a trough within the glaciolacustrine silts. Harrison (1995) described the idealized flow system in an upland-lowland setting as an: upland to lowland flow component recharged at high altitude and discharged along lower slopes and the valley bottom, and a flow component that is parallel to the valley bottom. This conceptual flow system is illustrated in Figures 10 and 11. This upland-lowland flow results in an upward flow beneath the river valley that is maintained by recharge and infiltration in the upland areas. Upland to lowland flow may also result in seeps or streams near local topographic lows and near the valley bottom. Figure 10 depicts a flow system with homogenous hydrostratigraphy. In reality three-dimensional flow is governed not only by the topography, but also the configuration of the various geologies. For this conceptual model, the flow is likely dominant in the most surficial layers because the hydraulic conductivity is relatively high and the recharge of water to the surface from precipitation. To identify common flow systems, mixing locations and water quality, several groundwater samples were collected in the Merritt area and analyzed for various geochemical parameters. The results of the chemical analysis were made available for this study by the City of Merritt, Urban Systems Ltd. and B C Groundwater Consulting Services Ltd. Furthermore, five additional groundwater samples were collected as part of this study on July 20"^ and 21^*, 2005. Chemistry results are included in Appendix C. The major ions in natural water are sodium (Na*), potassium (K^), calcium (Ca^^), magnesium (Mg^^), chloride (Cf), carbonate (COi^), bicarbonate (HCO3") and sulphate (S04^')- The concentration of these major ions can be plotted on a Piper plot to evaluate the changes in groundwater chemistry along a flow path. Groundwater chemistry from nine sampling locations along Coldwater valley are plotted on Figure 12. The samples collected up valley are most consistent with the freshwater chemistry of the Coldwater River. Down valley the chemistry becomes more characteristic of groundwater with higher concentrations of persistent ions such as Na^ and K^. The arrows on Figure 12 indicate a groundwater mixing trend with distance along Coldwater valley. The results observed on the Piper plot supports the upland-lowland groundwater flow setting since the groundwater collected from the wells down valley have groundwater chemistry indicative of mixing with upward flowing groundwater. Figure 13 shows a Piper plot for the groundwater samples collected near Merritt. These wells include the city productions wells and a Ministry of Environment monitoring well. According to the Piper plot, the samples collected are similar to the samples collected from Coldwater and Nicola Rivers. This may indicate that groundwater in the surficial aquifer is mostly recharged from the rivers. The regional hydrology is discussed in detail in section 6. For the purpose of the conceptual model, the Merritt area receives an average of 322 mm/yr of precipitation. The earlier analysis in section 6 indicates that an estimated 70 percent of the precipitation is removed from the system through évapotranspiration or for human use and 20 percent as runoff to streamflow. The remaining 10 percent, or 32 mm/yr, recharges the groundwater flow system. For the purpose of this model the river level remains constant and is not subject to any seasonal or long-term fluctuations in water level or discharge. To simulate the effects of the current groundwater demands for Merritt, the model includes the five City of Merritt production wells. Figure 10: Conceptual Flow Path 1500. 1000. Removal (ET, Human Usage) S Recharge (Precipitation) ^̂ ŜOftft ^^^'^ Boundary ^QQOQO Figure 11: Conceptual Flow Direction 5560000 5558000H\ 5556000H 5554000̂ 5552000H 5550000H 55480004 5546000H 1 \ 1 \ 1 654000 656000 658000 660000 662000 664000 666000 668000 0 1000 2000 3000 4000 5000 6000 Meters Recharge: R. Constant Head Boundary: h = c,. Hydrologie Boundary: ôh/ôn = 0 Groundwater Flow Equation: ô/ôx(K,ôh/ôx) + 5/ôy(K,5h/5y) + ô/ô2(K;ôh/ôz) + R = 0 - 3 6 - Figure 12: Piper Plot - Coldwater River Valley EXPLANATION O Ewalt • Parsoas A Boattio Mattias Trailer Paik * Swedberg • Boyce Spring • Boyce Well X Coldwater River Figure 1 SPiper Plot - Pi per Plot - btritt ttWs EXPLANATION O Minivin- Well Voght Park »1 Faifley Park May Street Voght Park »2 Coldwater Rivei Nicola Rîver Ca" Na +K 7.2 Pilot Scale C B M The objectives of the pilot scale model are to simulate the potential effects of coal seam dewatering in a relatively localized area. If C B M development were to proceed, it would likely begin as a pilot study in a relatively localized area before regional development would begin. The pilot study would be aimed at assessing the feasibility of C B M development on a regional scale. According to the B C Ministry of Energy and Mines the areas with the best potential for C B M resources are to the west and beneath the City of Merritt and Lot 166 (Figure 14) represents a plausible location for a pilot study. Development of C B M involves dewatering a coal seam using a network of pumping wells to enable methane volatilization. The groundwater flow towards the pumping well is largely dependent on the hydraulic conductivity of the surrounding porous media and the magnitude of the hydraulic gradient. To understand the effects hydraulic conductivity has on the system, the hydraulic conductivity values can be modified for each unit to obtain a variety of possible responses. The geometry of the geology in the Coldwater H i l l area is complex and thus difficult to represent accurately using the modeling software. Furthermore, an unconformity occurs between the Tertiary units and the overlying Quaternary sediments. This Tertiary sedimentary sequence was eroded along the unconformity so that several units, including coal seams, subcrop into the Quaternary sediments. Conceptually the model consists of a sequence of layered sedimentary rock with thin coal seams interbedded between units of sandstone/shale. The model must represent the coal seam subcrops and also the series of northwest-southeast trending faults. To simulate coal seam dewatering, a series of pumping wells were introduced to the coal seam, or coal seams that are interpreted to have methane producing potential. The wells are spaced at 200 metre intervals and the simulation time of the model was five years, as is typical of pilot scale studies. The model results were used to quantify the amount of groundwater that must be pumped from the coal seams to produce C B M . Furthermore, the results were also used to observe the groundwater flux at the interface between the Quaternary sediments and the coal seam subcrops as well as along the series of faults. It was assumed that groundwater flows from the Coldwater Hi l l area into the Merritt aquifer. If a significant amount of water were removed from the groundwater flow system in the Coldwater H i l l area, the result may be a partial depletion of a source to the Merritt aquifer. 7.3 Regional Scale C B M The objectives of the regional scale C B M model were to simulate the effects of C B M development over a regional scale. Due to the scale of this model, it was not feasible to represent the level of detail that is required to accurately define every feature of the hydrostratigraphy. Instead, results of the pilot scale model were used to infer the role of subcrops and localized faults for the regional system. The main feature of the geology that the regional model was used to evaluate was the strike-slip fault that extends from the southwest to the northeast of Merritt. This fault is interpreted to cut through the sedimentary basin and due to its presence and potential to affect the flow system of the area must be included in the conceptual model. In absence of sufficient hydrogeologic testing, it is difficult to describe a fault in terms of its hydrogeological properties, since there is a broad range of possible hydrogeologic properties for a fault zone. A fault can behave either as a conduit for groundwater flow or a barrier to groundwater flow. A s such, the numerical model was used to simulate a broad range of hydrogeological properties for the fault. The topography of the region and the configuration of the Quaternary units were the same as the base case model; however, the Tertiary geology differed. For a scenario involving coal seam dewatering, the coal seams were represented as thin layers interbedded between units of sandstone and shale. To simulate coal seam dewatering, a series of pumping wells were introduced to the coal seam, or coal seams, that are interpreted to have methane producing potential. The wells were spaced according to typical well spacing for regional C B M development regulations. The model results were used to examine the groundwater flux at the interface between the Quaternary sediments and the southwest-northeast trending fault. Figure 14: Approximrte Locatkm of Lot 166 J 1 \ 1 1 I I L 5560000- 5558000- 5556000- 5554000- 5552000- 5550000- 5548000- 5546000- Figure 14 has been removed due to copyright restrictions. The information removed illustrates the topography of the Merritt region and the approximate location of Lot 166. Information was posted on the BC .Ministry of Environment website http:// webmaps.gov.be.ca 654000 656000 668000 660000 662000 664000 666000 668000 0 1000 Color HIbhade frofn BC M l n l ^ of Environmont - t4tp://maps.gov.t}c.ca/ 00 4000 5000 6000 Motm 8.0 NUMERICAL MODEL Using the conceptual models formulated in section 7, a numerical model has been constructed using Visual M O D F L O W version 4.0.0.126. M O D F L O W is a modular three- dimensional groundwater flow model originally developed by the U.S. Geological Survey and currently by Waterloo Hydrogeologic Inc. The model is based on a block-centered finite difference formulation of the groundwater flow equation requiring all model layers to be continuous across the entire model domain. Each layer is required to have a finite layer thickness in order to assure conservation of mass and, hence, the stability and accuracy of the solution. Input parameters to the model domain include boundary conditions, hydrostratigraphic properties and recharge. M O D F L O W simulates groundwater flow under saturated conditions and can not simulate two-phase flow of gas and water. M O D F L O W was used for the pilot scale and regional scale C B M models simulate groundwater flow in response to coal seam dewatering. Using M O D F L O W for simulating coal seam dewatering likely introduces some model uncertainties since M O D F L O W can not simulate methane desorption as a result of reducing the hydrostatic pressure of the coal seam nor the reduced relative permeability of water during gas desorption. The relative permeability for water for each model is not transient; however, pilot scale and regional scale models simulate groundwater flow under a number of different hydraulic conductivity scenarios. 8.1 Base Case Model 8.1.1 Model Domain The size of the region to be entered into the base case model was chosen to reflect the hydrologie boundaries of the Merritt Basin (Figure 11). The entire watershed surrounding Merritt (Nicola and Coldwater River Watersheds) was not modeled because most of the watershed falls far outside of the region of interest (see further explanations in section 8.1.3). The size of the regional model is approximately 17 km by 17 km (28,900 hectares); however, the active region is irregular in shape and takes up approximately 20,000 hectares. Creating a three dimensional model in M O D F L O W requires importing surface topography and any other additional boundaries of geologic layers. In order to assure model convergence, the various layers in a M O D F L O W model must be laterally continuous. Waterloo Hydrogeologic Inc. specifies that large changes in elevation (especially when the model has thin layers) can cause adjacent cells to become laterally "detached", resulting in a lack of lateral continuity. This disables flow between cells in the same layer. As a rule of thumb, Waterloo Hydrogeologic Inc. specifies that vertical displacement between horizontally adjacent cells in the same layer should not be greater than approximately 50 percent of the cell thickness. Maintaining lateral continuity is particularly difficult to accomplish with thin layers in areas with steep slopes. For constructing the model framework, two methods were used to maintain lateral continuity. The first method was to create a grid with sufficient resolution so that the transition from cell to cell would be smooth and therefore less likely to suffer from discontinuity. Using a sufficiently fine resolution the region was modeled using 200 rows by 200 columns. This results in each grid cell being approximately 85 m by 85 m. The second method was to create fewer layers by combining geologic layers, thereby making the individual layers thick enough to ensure excessive displacement does not occur in areas where the terrain was steep. Although significant simplification of all geologic units must take place, the Tertiary sedimentary units require the greatest degree of modification to maintain lateral continuity. This is because several Tertiary layers, namely the coal seams, are thin and are subject to folding and faulting causing steep changes in elevation. For the purpose of the base case model, combining the Tertiary sedimentary units into composite layers is acceptable because the areas of interest in this model are the surficial layers in proximity to the City of Merritt. Building the model framework began by collecting data points that included the latitude, longitude and elevation for several locations relating to each geologic layer. These data points were then interpolated to provide a smooth surface that represents the layer surfaces. The surface topography was collected from B C Ministry of Environment Water Resources Atlas. Latitude, longitude and elevation information was collected from a total of 1268 points over the region. The data points for the surficial aquifer were collected using the B C Water Resource Atlas and also from a report provided by Kala Groundwater Consulting Ltd. (Kala) (2004) (Appendix A) . The Water Resource Atlas provides detailed well records for several wells in the Merritt area. Using these well records, the bottom of the aquifer and the lateral extent was interpreted into a series of data points. A total of 1185 data points were used to describe the bottom of the surficial aquifer. The entire surficial aquifer is confined within the Quaternary deposits including glaciolacustrine silts, tills, etc. The data points for the Quaternary sedimentary deposits were also collected using the B C Water Resource Atlas, including the detailed well records, and the Kala report (2004). The B C Water resource Atlas provides a layer that outlines the Quaternary deposits. This data was used to define the extent of the Quaternary deposits when collecting the data points. A total of 1173 data points were used to describe the bottom the Quaternary deposits. The sedimentary rock, which includes the coal seams, was relatively poorly defined as compared to the Quaternary geology. A series of cross sections (JHP, 2002), were used to define the bottom of the sedimentary rocks in the area near Coldwater H i l l . Additionally, three cross sections (Swaren, 1977) were used to interpret the depth of the various sedimentary layers for the remaining areas of the sedimentary basin. To maintain lateral continuity, the sedimentary layers were simplified into two coal bearing units surrounded by three sedimentary units. Based on the information available regarding the depth and extent of the geologic layers in the Merritt region, a total of nine geologic layers were created. The bottom layer represents the impermeable bedrock and is characterized by a no-flow boundary. The data points were interpolated with Surfer, a surface mapping software, to create a continuous surface. Because many of the layer surfaces were very steep in areas, especially the sedimentary geology as it is folded and faulted, the layers were smoothed in Surfer. This was another means of maintaining lateral continuity by mitigating the effects of steep slopes. Once the layer surfaces were created they were imported into M O D F L O W . Although the simulated composite layers are thicker than the individual component layers that they represent, this simplified three-dimensional framework provides a reasonably good approximation of the region given the constraints of the modeling software and the limited information available of the subsurface geology. Fortunately, the most important layers in this model, the Quaternary sediments, are likely the most accurately represented in the model. 8.1.2 Hydrostratigraphy To date, there have been no physical hydrogeological investigations in the Merritt area apart from the surficial aquifer beneath Merritt. E B A Engineering Consultants Ltd. prepared a report titled Aquifer Protection Plan for the City of Merritt in 2002 and Kala Groundwater Consulting Ltd. prepared a report titled Groundwater Potential Evaluation and Test Well Siting Study for the City of Merritt in 2004. A summary of the hydraulic properties collected from production wells completed in the surficial aquifer is provided in Table 3. The results of the E B A and Kala reports suggest that the hydraulic conductivity of the surficial aquifer ranges from 6x10'^ to 2x10"' cm/s. Since there is no other measured hydrogeological data from the Merritt region, the remainder of the hydrogeological parameters were estimated based on typical ranges of values for the various geological units. Freeze and Cherry (1979) presented typical hydraulic conductivity values for various geological media (Figure 15). Once the model framework was constructed, the hydraulic conductivity data was entered into M O D F L O W . Table 4 presents the horizontal hydraulic conductivities used for each layer in the base case model. For each of the sedimentary units the vertical hydraulic conductivity is assumed to be an order of magnitude less than the horizontal hydraulic conductivity. The hydraulic conductivity for the units composed of volcanic bedrock is assumed to be the same in all directions. To determine the effects that hydraulic conductivity has on the groundwater flow in the surficial layers, three sets of hydraulic conductivity values were used. The three sets of values presented in Table 4 for layers 1 and 2 represent a high, medium and low hydraulic conductivity case within the range Table 3: Summary of Production Well Completion Data and Hydraulic Properties • Well Year of Completion Diameter Completion Data Static Water Level Hydraulic Properties Estimated Saturated Ttiickness (m) Aquifer Response Total Deptti (m) Screen Interval (m) Deptti (m) Date Measured Specific Capacity (L/s/m) Date Measured Transmissivity (m'/s) Hydraulic Conductivity (m/s) Collettevllle Jul-78 254 mm 49.1 37.6 0-45.1 4.1 Aug-78 43 Unknown 8.00E-02 2.00E-03 >45.3 Leaky-Confined Aquifer 4.3 Sep-96 23 Unknow/n Fairly Park Jan-66 305 mm 29.9 19.2-25.3 1.86 Feb-71 17 1966 2.00E-02 1.00E-03 23.4 Leaky-Confined Aquifer 29 Jun-78 May Street Oct-70 305 mm 30.5 7.6-10.7 2.89 Oct-70 8.8 Unknown 1.00E-02 1 .OOE-03 7.8 Unconfined Aquifer 2.9 1972 12 Dec-91 Voght Park #1 Jul-71 406 mm 29,9 20.7-29.9 2.56 1971 8.7 Jul-71 5.00E-02 2.00E-03 26.2 Leaky-Confined Aquifer 3.48 Sep-76 Voght Park #2 Sep-76 406 mm 34.8 9.8-34.1 3.63 Sep-76 18 Sep-76 2.00E-02 6.00E-04 31.1 Leaky-Confined Aquifer 8 Jan-90 ' Data summarized from EBA Aquifer Protection Plan. 2002 measured by E B A (2002), Kala (2004) and B C Groundwater. Hydraulic conductivity values for the remaining geologic units were chosen within their respective ranges presented on Figure 15. Table 4: Base Case - Range of Values of Hydraulic Conductivity for each Layer Layer # Unit Description Horizontal Hydraulic Conductivity (cm/s) Low Medium High 1 Alluvium/Coliuvium 5.0E-02 1.0E-01 5.0E-01 1b Colluvium/Fractured VOLCANICS 5.0E-03 2 Lacustrine SILT/TILL 5.0E-04 1 5.0E-03 | 5.0E-02 2b Fractured VOLCANICS 1.0E-05 3 SHALE and SANDSTONE 5.0E-07 3b weathered VOLCANICS 1.0E-07 4 SHALE and SANDSTONE with interbedded COAL seam 1.0E-05 4b VOLCANIC bedrock 1.0E-08 5 SHALE and SANDSTONE 5.0E-07 5b VOLCANIC bedrock 1.0E-08 6 SHALE and SANDSTONE with interbedded COAL seam 1.0E-05 6b VOLCANIC bedrock 1.0E-08 7 SHALE and SANDSTONE 5.0E-07 7b VOLCANIC bedrock 1.0E-09 8 VOLCANIC bedrock 1.0E-09 9 IMPERMEABLE - Figure 15: Range of Values of Hydraulic Condoctivity and Permeability From Freeze and Cherry (1979) Flocks S o w » * SI? M n M T> O O Î £ f * l t - i | J-6 ÎS U . fe-o T> it a t5 o TO r u n k k K «: K (dorcyl fcfii^ 'Cffi/sî (mA( (got/doy/ff^) -10* -to* 10* - t o ' M O - r 1 -10-^ -10 •10-' -iO^ -1 -10^ -10^' 10-' l.o -io-^ - t o * -1 - !0- ' .10'* - t o - 10-* to ^ - 1 0 ^ -10-» -to-* - to-" -I0-* io-« M O ' -10-'* -10-» - t o ' - 10''' -ID-*" - io-« -10-'* - i o - « H 10 lo-* LlO-^ P « f t T i M b i l i l y . * • cm* an* I \M ^. 10'' darcy 9.87^10-4 1,06 x lCT' ' iTi,-s I oa X I0-' I-IO < fl/s 3.11 X lO-' Î.35 K 10" U.S. gal/<tey,ft'5.42 X Sff-i" 5.83 x 10"" dercy 1.01 V. 10« 9.42 X 10'» I \.m y. 103 3.15 X 10* Î.49 X to-* *To o»«ain * in ft*, multiply * ia cm* by 1.08 x 10 ». Hydraulic cundoctiVKt^. K 9.S0 X 10* 9.11 X 9.66 y~ 1 3 05 .V 4.72 10' 10-* 10 » 10-̂ U.S. aal/aay/f!= .1.22 ;< 10' 2.99 X 10* 3.17 X 10-' 3.28 1 1.55 X 10-« 1.S5 X 10* 1.71 y lOf» 1»2 X 101 2.12 X 10' 6.46 X 105 1 The top two layers consist of alluvial/colluvial sediments and glaciolacustrine silts and till in the valley and colluvium and fractured volcanics in the slopes and hills. The subsequent six layers consist of sedimentary units surrounded by weathered volcanics. The bottom most active layer consists of weathered bedrock. It is assumed that the hydraulic conductivity of the volcanics decrease with increasing depth as the influence of surface processes (i.e. erosion, compressional effects of glaciation, etc.) decreases, thereby reducing the amount of weathering. Furthermore, as the depth increases, so does the weight of the overlying material, which causes more compaction of the geological matrix, thereby decreasing the rock's permeability. Figure 16 shows the configuration of the hydraulic conductivity for each layer. A fault zone is represented in layers three through eight where there has been displacement of the layers across a fault plane. The fault is assumed to be vertical and the hydraulic conductivity of the fault is poorly constrained. Accordingly, a range of conductivity values between 1x10'* cm/s and 1x10"''' cm/s are assigned to the fault plane. M O D F L O W requires values for specific storage, specific yield, effective porosity and total porosity. Storage is not considered crucial since most of the analyses focus on steady-state conditions, which are not affected by storage properties. There have been no hydrogeological investigations that determine the storage values in the Merritt area, and consequently the storage values are estimated based on typical ranges of values for the various geological media. The values for specific yield and porosity were chosen based on typical values provided by Dominico and Schwartz (1998). Specific storage (Ss) was calculated using an equation from Fetter (2001): Ss = pwg(a + nP) Where a Pw g n is the density of water (1000 kg/m^) is the acceleration due to gravity (9.8 m/s^) is the compressibility of the aquifer is the total porosity is the compressibility of water (4.6 x 10'"^ msVkg) Figure 16: Hydraulic Conductivity Configuration It is likely that the compressibility of the aquifers is important when determining the specific storage; however, since a is unknown, the aquifers are assumed to be incompressible. I f taking into account aquifer compressibility, the value for specific storage would increase. Thus the equation for specific storage becomes: Ss = pwgnp Using the estimated total porosity for each of the geologic units, and assuming g and P are constant, the specific storage can be found using the above equation. The values of specific yield, specific storage and porosity used for each of the geologic units are presented in Table 5. Under steady-state conditions, the storage values are not considered to be of critical importance to the model. Therefore, an assessment of the effects of storage was not undertaken as part of this study. Table 5: Storage Values for Various Geologic Media Layer # Unit Description Specific Yield Compressibility (m /̂N) Specific Storage (1/m) Porosity 1 Alluvium/Coiluvium 0.25 1.00E-07 9.8E-04 0.3 1b Colluvium/Fractured VOLCANICS 0.2 5.00E-08 4.9E-04 0.35 2 Lacustrine SILT/TILL 0.15 2.00E-08 2.0E-04 0.2 2b Fractured VOLCANICS 0.1 5,00E-10 5.6E-06 0.15 3 SHALE and SANDSTONE 0.1 1.00E-08 9.9E-05 0,2 3b weathered VOLCANICS 0.08 3.00E-10 3.4E-06 0.1 4 COAL 0.05 3.00E-08 3.0E-04 0.2 4b VOLCANIC bedrock 0.08 2.00E-10 2.4E-06 0.1 5 SHALE and SANDSTONE 0.1 1.00E-08 9.9E-05 0.2 5b VOLCANIC bedrock 0.08 1.00E-10 1.4E-06 0.1 6 COAL 0.05 3.00E-08 3.0E-04 0.2 6b VOLCANIC bedrock 0.08 1.00E-10 1.4E-06 0.1 7 SHALE and SANDSTONE 0.1 1.00E-08 9.9E-05 0.2 7b VOLCANIC bedrock 0.08 1.00E-10 1.4E-06 0.1 8 VOLCANIC bedrock 0.08 1.00E-10 1.5E-06 0.1 9 IMPERMEABLE - - - - The initial head in the base case model was imported from a steady state simulation of the base case model without the influence of the City of Merritt production wells. According to Ka l a (2004), the City of Merritt extracts approximately 100 litres per second (L/s) on an average annual basis from the surficial aquifer via five production wells. Approximately 68 percent of the production is supplied from the Voght Park wells. Table 6 includes the historical and present pumping rates for each of the wells. E B A (2002) suggested that the City of Merritt would likely require approximately 120 L/s by 2010. E B A (2002) found that extraction rates in excess of 100 L/s may impact the aquifer as a whole and may potentially cause production well interference. The five production wells used to supply Merritt with their potable water supply are the Voght Park #1, Voght Park #2, Fairley Park, May Street, and Collettville pump stations. The historical information on the pumping rates for each well provided by the City of Merritt is limited to 1993; however, each well has been in operation since before 1993. 1 Voght Park #1 Voght Park #2 Fairley Park May Street Collettville 1 1993 43.4 19.7 17.4 5.2 - 1994 6.2 76.8 14,3 4.4 - 1995 5.2 72.7 13.2 4.2 - 1996 15.6 67.7 5.2 1.2 1997 4.2 53.5 25.7 0.8 13.4 1 1998 7.5 67.0 19.5 0.0 14.9 1999 22.8 49.5 23.9 1.6 4.6 2000 20.9 42.0 16.4 1.2 15.4 2001 23.5 48.0 22.8 0.9 9.6 2002 23.2 47.1 23.3 1.8 5.9 2003 13.6 50.6 16.2 1.1 21.9 2004 25.5 43.7 20.4 0.8 12.5 2005 4.1 54.2 32.2 0.7 10.7 2006 1.4 24.2 16.7 0.2 3.5 Total 217.0 716.8 267.3 23.9 112.5 Average (L/s) 15.5 51.2 19.1 1.7 10.2 Average (m'/d) 1339.5 4423.6 1649.7 147.7 883.6 For the purpose of simulating pumping at these five stations, the average pumping rate at each well is used for each year it was in use. 8.1.3 Boundary Conditions For the base case model three different boundary conditions were used: an impermeable boundary (i.e. no flow), a specified head boundary and a specified flux boundary. As described above the base case model occupies approximately 20,000 hectares in the Merritt region. The lateral boundaries of the model follow the topographic highs in the area and it is assumed that surface water and groundwater on the outside of these boundaries would flow away from the modeled area. These boundaries are considered hydraulic divides and they are assumed to create a no flow boundary. Geological features such as tilted bedrock and dipping faults may cause errors in the assumed boundaries i f water flows into the modeled area from outside the boundaries or vice versa. The entire watershed surrounding Merritt (Nicola and Coldwater River Watersheds) was not modeled because most of the watershed falls far outside of the region of interest. In order to constrain the size of the model, the boundaries of the model do not follow the assumed hydraulic divide in three areas. These three areas are characterized by two rivers flowing into the model (Nicola and Coldwater Rivers) from the east and south and one river flowing out (Nicola River) to the west. The water level in the rivers is assumed to be relatively constant and therefore these three areas are represented with a constant head boundary value at the surface. Furthermore, for the remaining reaches of the rivers, a constant head boundary was applied at an elevation equal to the ground surface. To constrain the depth of the model, a no flow boundary was assigned to stable bedrock. As discussed above, the volcanic bedrock is assumed to be weathered until some depth below the Tertiary sedimentary units and/or the Quaternary sediments. The thickness of the weathered volcanics is very subjective, however; the hydraulic conductivity of the volcanics is always low compared to the hydraulic conductivity of the surrounding geology. Therefore, groundwater flow within the volcanics is likely to be relatively insignificant. As discussed in Section 6.0 and simulated by a V A D O S E / W model the groundwater recharge in the basin is likely between 6 and 10 percent of the total precipitation. The recharge boundary was applied to the top layer of the model with a value of 30 mm/year. Figure 17 shows a typical cross section from west to east through the model and Figure 18 shows the plan view of the model with the applicable boundary conditions. Figure 17: Model Cross-Sect ion through Merritt Basin Topographic Contours at 100m intervals 8.2 Pilot Scale Model 8.2.1 Model Domain The pilot scale model covered an area to the southwest of Merritt in the Coldwater H i l l area. The modeled area was near or within the bounds of Lot 166 (Figure 14). The area of the model is approximately 6 km by 6 km (3,600 hectares), however; the active region is irregular in shape and takes up approximately 1,750 hectares. Within this area there is a surface layer that represents the aquifer sediments in the valley and coUuvium/weathered bedrock in the hills. Below this layer are the volcanic bedrock and the Tertiary sedimentary units. The grid cells in the area occupied by the Tertiary sedimentary units is approximately 10 m by 10 m, and the grid size in the area occupied by the volcanics is 100 m by 100 m. The reason for the fine grid size in the area of the Tertiary units is that this is the region of interest. The entire pilot scale model is within the bounds of the base case model and therefore the topography used for the base case model was also used for the pilot scale model. The geology in this area was interpreted through a series of maps and cross-sections prepared by JHP (2002) and Swaren (1977). As discussed above, M O D F L O W does not allow laterally detached layers or layers with zero thickness. Because of this it is very difficult to simulate the highly folded and faulted sedimentary units of in the Coldwater Hi l l area. Furthermore, modeling subcrops is difficult since layers cannot pinch out. To maintain lateral continuity and still adhere to the objectives of the model, the coal seams were modeled as a series of layers with uniform depth and thickness. A total of four coal seams were entered into the model, each with a thickness of 10 m. The depth of each coal seam was assumed as an approximate average of the actual depth. The locations of the subcrops of the coal seams were based on the map prepared by Swaren (1977). The trace of the subcrop was copied vertically downwards until its respective coal seam was encountered. As a result, the subcrop and the coal seam meet at a ninety-degree angle. The thickness of the coal seam and subcrop are uniform at 10 m. In this way, the general shape of the synclinal structure of the coal seams is maintained as well as the lateral continuity. The faults in the area were entered as vertical features that cut through the Tertiary sedimentary units. 8.2.2 Hydrostratigraphy To date, there has been no hydrogeological investigation in the Coldwater H i l l area. Consequently, all of the hydrostratigraphic properties are estimated based on the Freeze and Cherry (1979) values (Figure 15). Since the estimates of the range in hydraulic conductivity are broad, several different scenarios were simulated with varying hydraulic conductivities. Table 7 presents the hydraulic conductivities used for the pilot scale model. Table 7: Pilot Scale Model - Range of Values of Hydraulic Conductivity for each Layer Layer Horizontal Hydraulic Conductivity (cm/s) # Unit Description Low Medium High 1 Merritt Aquifer 5.0E-01 1b Colluvium/Fractured VOLCANICS 1.0E-07 5.0E-02 2 SHALE and SANDSTONE 1.0E-09 5.0E-08 1.0E-07 3 COAL 1.0E-06 1.0E-05 1.0E-04 3b SHALE and SANDSTONE 1.0E-09 5.0E-08 1.0E-07 4 SHALE and SANDSTONE 1.0E-09 5.0E-08 1.0E-07 5 COAL 1.0E-06 1.0E-05 1.0E-04 5b SHALE and SANDSTONE 1.0E-09 5.0E-08 1.0E-07 6 SHALE and SANDSTONE 1.0E-09 5.0E-08 1.0E-07 7 COAL 1.0E-06 1.0E-05 1.0E-04 7b SHALE and SANDSTONE 1.0E-09 5.0E-08 1.0E-07 8 SHALE and SANDSTONE 1.0E-09 5.0E-08 1.0E-07 9 COAL 1.0E-06 1.0E-05 1.0E-04 9b SHALE and SANDSTONE 1.0E-09 5.0E-08 1.0E-07 10 SHALE and SANDSTONE 1.0E-09 5.0E-08 1.0E-07 11 IMPERMEABLE - - Faults 5.0E-10 - 5,0E-05 The same storage parameters were used for the pilot scale model as were used in the base case model. Since the vertical subcrops and faults cannot be represented as layers, they were represented as cells with distinct hydraulic conductivity values. Consequently, the hydraulic conductivity is the same in the subcrops as it is in the coal seams. Figure 19 shows a typical cross-section for the pilot scale model and Figures 20 and 21 show the location of the subcrops and faults in plan view in layer 2 and 7, respectively. Figure 19: Pilot Scale Model - Typical Cross-sect ion Figure 20: Pilot Scale Model Plan View of Layer 2 8.2.3 Boundary Conditions In order to limit the size of the model, the boundary conditions were not always aligned with distinct physical boundaries. As with the base case model, the size of the pilot scale model was based on the locations of the hydrologie divides. This assumption is likely valid in the hills to the west and south of the modeled area, however; it may not be valid to the east and north. The boundary chosen for the east and north of the modeled area was Coldwater River. Rivers can act as hydrologie divides, but unfortunately, due to the understanding that the Tertiary sedimentary units dip under and away from the Coldwater River, it is unlikely that this constitutes a hydrologie divide at depth within the Tertiary geology. The coal seam subcrops and the faults, which are the areas of prime interest in the pilot scale model, are located closer to the west and south boundaries and therefore the east boundary has little effect on the results of the model. To test the effect of a no- flow boundary along Coldwater River, the results of the model were compared to using a constant head boundary condition. The constant head boundary was applied beneath Coldwater River and was set to just below the ground surface through the entire depth of the model. Upon reviewing the results of the model, it was determined that applying a constant head boundary beneath the Coldwater River did not change the flux from the surface layer into the subcrops and faults. Applying a constant head boundary did, however, increase the total groundwater flow through the system. Furthermore, the pumping rate for C B M pumping wells close to the constant head boundary also increased. The use of a constant head boundary beneath Coldwater River is likely not a realistic condition since the head most likely changes between the stratigraphie units. If the coal seams are relatively continuous the head is likely higher in the areas of the syncline than represented by the constant head used in the model. If the head is higher in the coal seams there wil l be less flow through the system and the conditions become closer to the no flow boundary condition case. At this time there are no head measurements in the Tertiary sedimentary rock and therefore, the boundary conditions in this case are only conceptual. Nevertheless, although it is important to note that the pumping rates presented with the modeling results may be higher if a constant head boundary were used, a no flow boundary was used during the simulation of the pilot scale coal seam dewatering. Unlike the base case model, the contact between the volcanics and the Tertiary sedimentary rock in the pilot scale model is considered a no flow boundary, with exception to the top layer that consists of a composite colluvium/volcanics unit. In the pilot scale model, the attention is placed on the coal seams and the small amount of groundwater flow in the volcanics over the duration of five years is likely not significant. For the pilot scale model a constant head boundary is applied to the surface of the top layer. One of the objectives of the pilot scale model was to model the flux into the coal seam as a resuh of dewatering. In M O D F L O W , i f a cell becomes dry, it becomes inactive. Section 9.2 compares the simulated flux to the estimated recharge to indicate i f the boundary condition is valid. Since the hydraulic conductivity (in most cases) is higher in the top layer than in the lower layers, the top layer in the Pilot Scale model acts as a constant water reservoir with a constant head boundary. Consequently, the model is not able to show the occurrence of drawdown in the surficial materials. However, the model is able to qualitatively and quantitatively estimate the groundwater flux from the surface layer into coal seams and faults as coal seam dewatering occurs. Constant head boundaries were also used to simulate the C B M well field. If the layer is defined as a confined system, a constant head in a cell with a head value at or near the bottom elevation of the cell wi l l simulate dewatering the coal seam without causing the cell, or adjacent cells to become dry. According to a report prepared by Westwater Mining Ltd. (2003), the coal seams with the greatest development potential are the lower coals that are represented in the pilot scale model as layers 7 and 9. The constant head cells, simulating fixed drawdown wells, were placed at 200 m spacing over the entire coal seams represented in layer 7 and layer 9. 8.3 Regional Scale Model The regional scale model was constructed much like the base case model. The topography is the same, the size and shape of the model area are the same, and the boundary conditions are the same. The major difference is that in the regional scale model the coal seams are represented as flat continuous units similar to the pilot scale model, in contrast to the base case model where the coal seams are represented as thicker composite sedimentary layers. The depth of the coal seams was based on the cross- sections prepared by Swaren (1977). Table 8 shows the ranges of hydraulic conductivity values that were modeled as part of the regional scale model. For the Regional scale model, the only hydrostratigraphic property that was varied was the hydraulic conductivity of the fault. Table 8: Regional Scale Model - Range of Values of Hydraulic Conductivity for each Layer Layer # Unit Description Horizontal Hydraulic Conductivity (cm/s) Low 1 Medium High 1 Alluvium/Coliuvium 5.0E-01 1b Colluvium/Fractured VOLCANICS 5.0E-03 2 Lacustrine SILT/TILL 1,0E-03 2b Fractured VOLCANICS 1.0E-05 3 SHALE and SANDSTONE 5.0E-07 3b weathered VOLCANICS 1.0E-07 4 COAL 1.0E-05 4b VOLCANIC bedrock 1.0E-08 5 SHALE and SANDSTONE 5.0E-07 5b VOLCANIC bedrock 1.0E-08 6 COAL 1.0E-05 6b VOLCANIC bedrock 1.0E-08 7 SHALE and SANDSTONE 5.0E-07 7b VOLCANIC bedrock 1.0E-09 8 VOLCANIC bedrock 1.0E-09 9 IMPERMEABLE - - Faults 1.0E-10 5.0E-05 1 1.0E-04 9.0 M O D E L RESULTS 9.1 Base Case Model The objectives of the base case model were to define the hydrogeological conditions of the Merritt region, simulate the drawdown of the City of Merritt production wells and estimate an overall water balance for the regional system. The simulated time of the base case model was for a duration of 50 years from 1960 to 2010. Each of the five production wells began pumping at its year of completion (Table 3) and continued to pump groundwater at an average rate until 2010. Figure 22 illustrates the modelled groundwater contours and groundwater flow vectors. Figure 23 illustrates some groundwater flow paths with the addition of modelled particles. Figures 24 through 26 plot the stream leakage and the groundwater discharge into the stream in response to groundwater pumping from the five City of Merritt pumping wells for three hydraulic conductivity scenarios. For each of the scenarios it is observed that as pumping from the city production wells increases, stream leakage also increases. Furthermore, groundwater that was modelled as discharging into streamflow is reduced during pumping. At conditions close to steady state, the summation of the reduction in groundwater discharge into streamflow and stream leakage accounts for the majority (between 93 and 98 percent) of water that is pumped by the city production wells. In all scenarios, water from stream leakage is the greatest source of recharge to the aquifer accessed by the city production wells. As such, the drawdown created as a result of groundwater extraction is largely controlled by the location of the river. Based on the results of the simulation, groundwater produced from the Merritt aquifer is largely supplied from stream leakage from Nicola River and/or Coldwater River and to a lesser extent from groundwater flowing into the aquifer from upland areas. The results are supported by the Piper plot of groundwater and surface water chemistry plotted on Figure 13. The chemistry of the surface water and groundwater is of similar type, with little influence from deep groundwater. The minimum daily streamflow recorded at hydrometric Station 08LG007 (Figure 7) over the period from 1958 to 2006 was 0.552 mVs. The value which ten percent of the streamflow values fall below, or the 10 percentile, for the low streamflows at station 08LG007 is 2.61 mVs. Modelling simulated approximately 0.095 mVs of stream leakage as a result of pumping from the city production wells at 0.1 m^/s. At the current rate, the pumping wells wi l l not deplete Coldwater and Nicola rivers.  Figure 23: Groundwater Particle Tracking and Head Contours for Base Case Model Red arrows indicate downward groundwater flow. Blue arrows indicate upward groundwater flow. Arrows are at 10 year intervals. 100 Figure 24: Groundwater Flowing in and out of Nicola River During Production Well Pumping Low Hydraulic Conductivity Scenario 90 80 70 ^ 60 oc I 40 30 20 10 1500 t •Stream to S&G -S&G to Stream ± 2500 3500 4500 5500 6500 Simulation Time (days) 7500 8500 9500 100 Figure 25: Groundwater Flowing in and out of Nicola River During Production Well Pumping Medium Hydraulic Conductivity Scenario 90 80 70 _ 60 S 50 I u. 40 30 •Stream to S&G •S&G to Stream 20 10 f 1500 2500 3500 4500 5500 6500 Simulation Time (days) 7500 8500 9500 300 250 200 Figure 26: Groundwater Flowing in and out of Nicola River During Production Well Pumping Higii Hydraulic Conductivity Scenario • • t i (0 150 oc o u . —•—Stream to S&G • ^ - S & G to Stream 100 50 0 1500 2500 3500 4500 5500 6500 7500 8500 9500 Simulation Time (days) 9.2 Pilot Scale Model A pilot scale study is not meant to operate for a long duration, so the simulated time of the model was a total of 5 years. The objectives of the pilot scale model was to assess the feasibility of coal seam dewatering and estimate the potential groundwater flux from the surficial aquifer material into coal seams and faults in response to dewatering. To estimate the response to simulated coal seam dewatering a series of zone budget zones were applied. Zone budget computes subregional water budgets using results from the M O D F L O W groundwater flow model. For the pilot scale model several zones were defined, including: • Cells that represent pumping wells near subcrops, • Cells that represent pumping wells near faults, • Cells that represent pumping wells in relatively continuous coal seams, • Near the unconformity within coal seam subcrops that are being de-watered, • Near the unconformity within coal seam subcrops that are not being de-watered, and; • Near the unconformity within faults. A zone budget within a cell with a pumping well shows the rate at which groundwater is pumped from a well completed in the coal seam. Several cells were defined as zones for each zone budget. The results for the zone budget were then averaged to obtain a budget per cell. As such, the results provided in this section for wells completed in a coal seam represent the pumping rates for one individual well. A zone budget near the unconformity shows the groundwater flux from the surficial material into the coal seam subcrop or fault. Several cells were defined as a zone for each of these zone budgets. The results were averaged per cell, then divided by the area of a grid block (assuming the majority of groundwater flows vertically through the cell) giving a flux value. Figure 27 shows the locations of the zone budget cells. The zone budget results of the model simulation are included in Figures 28 through 32. Each figure consists of four zone budget plots. Three of the plots show the pumping rate for wells in specified areas within two separate coal seams, while one plot shows the groundwater flux in specified areas along the unconformity. For the purpose of this model all C B M production wells were started at the same time. In reality there would be a staged approach as additional wells are completed. Figures 28, 29 and 31 can be used to assess the role that faults play on the groundwater flow of the system. The results for a medium hydraulic conductivity fault are very similar to the results for a low hydraulic conductivity fault in that there is little to no groundwater flux from the surficial layer when the hydraulic conductivity of the fault is less than its surrounding media. The pumping rate for wells near faults is slightly higher for medium hydraulic conductivity faults than low hydraulic conductivity faults. However, when a high hydraulic conductivity fault is introduced, groundwater flux is much higher as is the pumping rate for wells near faults. Groundwater flux is 0 m^m"^/day and 1.1x10'* 3 2 2 m m' /day for low and medium hydraulic conductivity faults, respectively and 3.3x10" m^m'̂ /̂day for a high hydraulic conductivity fault. Although there are no estimates of the thickness of the fault, i f the faults are 4.5 km long and 10 m thick the amount of groundwater that is drawn into the faults in response to coal seam dewatering is approximately 1,500 m^/day. Comparatively, groundwater loss into the faults equates to approximately 18 percent of the amount of groundwater pumped from the City of Merritt production wells. Coal seam dewatering may prove difficult in areas near high hydraulic conductivity faults since approximately 50 m^/day must be removed from each well as the system approaches steady state. Conversely, approximately 1 to 3 m^/day must be pumped from each well close to low or medium hydraulic conductivity faults. In areas near subcrops and where the coal seam is continuous, there is little to no difference in the pumping rates despite the range of hydraulic conductivity in the faults. •vl © Zone Budget Cells Figure 28: Pilot Sca le Model - Zone Budget High K Fault -Layer 7 - Layer 9 1000 Time (days) 2000 Pumping Rates for wells situated in continuous Coal Seam - Layer 7 -Layer 9 500 1000 Time (days) 1500 2000 - Layer 7 -Layer 9 1000 1500 2000 Near Surface Groundwater Flux in Response to CBM pumping 6.0E-02 1— — - — 0 200 400 600 800 1000 1200 1400 1600 1800 2000 Time (days) - Within Faults —•— Inactive Outcrops — A c t i v e Outcrops Figure 29: Pilot Sca le Model - Zone Budget Low K Fault -Layer/ - Layer 9 2000 Pumping Rates for wells situated in continuous Coal Seam - Layer 7 -Layer 9 2000 .00 -r— -Layer/ -Layer 9 1000 Time (days) 1500 2000 Near Surface Groundwater Flux in Response to CBM pumping 200 400 600 800 1000 1200 1400 1600 1800 2000 Time (days) [-K-Within Faults -•-Irmctive Outcrops - ^ A c t i v e Outcrops] Figure 30: Pilot S c a l e Mode l - Zone Budget High K 250,00 200.00 150,00 •- - o 00.00 50,00 0.00 -Layer? -Layer 9 500 1000 Time (days) 1500 2000 - Layer 7 -Layer 9 0.00 5.00 - - 500 1000 1500 2000 Pumping Rates for wells situated in continuous Coal Seam 30.00 T — - Near Surface Groundwater Flux in Response to CBM pumping -Layer 7 -Layer 9 O.OE+00 200 400 600 500 1000 Time (days) 1500 2000 800 1000 1200 Time (days) 1400 1600 1800 2000 -WiUiin Faults • - Inactive Outcrops -Active Outaops Figure 31: Pilot Scale Model - Zone Budget Medium K -Layer? -Layer 9 j 500 1000 Time (days) 1500 2000 Pumping Rates for wells situated in continuous Coal Seam 14.00 1 — — —1 9.00 8.00 7.00 ? 6.00 "g 5.00 S S. 4.00 i o 3,00 2.00 1.00 0.00 I -Layer? -Layer 9 500 1000 1500 2000 Near Surface Groundwater Flux in Response to CBM pumping -Layer? -Layer 9 500 1000 Time (days) 2000 0 200 400 600 80O 1000 1200 1400 1600 1800 2000 Time (days) r-^<-Within Faults -•-Inactive Outcrops Active Outaops] Figure 32: Pilot Sca le Model - Zone Budget Low K -Layer? - Layer 9 500 1000 Time (days) 1500 2000 Pumping Rates for wells situated In continuous Coal Seam -Layer? - Layer 9 2000 1.80 T — 1.60 1.40 1.20 1.00 0.80 0.60 0.40 0.20 0.00 -Layer? -Layer 9 500 1000 1500 2000 Near Surface Groundwater Flux in Response to CBM pumping 800 1000 1200 Time (days) 2000 -Within Faults - Inactive Outcrops -*—Active Outgops | Figures 30 through 32 can be used to assess the role of hydraulic conductivity in the Tertiary sedimentary units as it relates to pumping rate and flux from the surficial layer. The effect of varying hydraulic conductivity is most predominantly observed in wells near coal seam subcrops. The peak groundwater pumping rate in layer 9 near subcrops is approximately 190 m^/day for the high hydraulic conductivity case as opposed to 32 m^/day for the medium hydraulic conductivity case and 5 mVday for the low hydraulic conductivity case. Furthermore, as the pumping rate approaches steady state, the pumping rate is approximately 155 m^/day for the high hydraulic conductivity case in layer 9, as opposed to 18 mVday for the medium hydraulic conductivity case and 1.7 mVday for the low hydraulic conductivity case. The effect of varying hydraulic conductivity is less pronounced in areas near continuous coal seams. For layer 9 peak pumping rates are 25 m^/day, 13 m^/day and 3.25 m^/day for high hydraulic conductivity, medium hydraulic conductivity and low hydraulic conductivity cases, respectively. A s pumping rates approach steady state, pumping rates are 5 m^/day, 1.8 m^/day and 0.1 m^/day for high hydraulic conductivity, medium hydraulic conductivity and low hydraulic conductivity cases, respectively. As a comparison, the city of Merritt production wells pump an average of 8,640 mVday. Hydraulic conductivity also has an effect on the duration of peak pumping rates. With decreasing hydraulic conductivity, the duration of peak pumping rate is prolonged. Elevated pumping rates were observed for high hydraulic conductivity, medium hydraulic conductivity and low hydraulic conductivity for a duration of approximately 100 days, 250 days and 500 days, respectively. The results of flux from the surficial layer into a coal seam that is being pumped indicate that i f hydraulic conductivity changes by an order of magnitude, so does the flux. Groundwater flux into the active coal seam for high hydraulic conductivity, medium hydraulic conductivity and low hydraulic conductivity were 7.6xl0'^ m^'Vday, 7.5x10"^ m^m'^/day and 7.4x10"'' m^m'Vday, respectively. Initially the flux rates were 4.2x10"^ m^m'^/day, 4.2x10"^ m^m"^/day and 4.2x10"* m^m"^/day for high hydraulic conductivity, medium hydraulic conductivity and low hydraulic conductivity, respectively. It is important to understand the feasibility of dewatering the coal seam when developing for C B M . Unfortunately the model cannot indicate whether or not the coal seam has been dewatered because of difficulties with dry cells and unsaturated groundwater flow. The model predicts that the hydraulic head throughout the coal seams drops substantially from the initial conditions during C B M production for each of the three hydraulic conductivity scenarios. The amount of head drop depends on the proximity to faults and especially subcrops, the distance from the production wells and the hydraulic conductivity of the coal seam. The smallest head drop occurs near subcrops, further away from the production well and for high hydraulic conductivity coal seams. The highest head drop occurs in relatively continuous coal seams near production wells and with low hydraulic conductivity coal seams. A large head drop indicates that a coal seam has potential for dewatering. Based on the results of the models, perhaps the best way to assess the feasibility of coal seam dewatering is to observe the amount of produced water. Since dealing with the produced water is likely to have financial costs that are dependant on the quality and volume of the produced water, there is likely a point where increased volume wi l l not be financially feasible. In order to better understand the impact that subcrops and faults have on the groundwater pumping rates and the groundwater flux from the surficial layer, an additional scenario was simulated where coal seam dewatering was only undertaken in the area of the relatively continuous coal seams. This modified scenario was only for a medium hydraulic conductivity case and the zone budget results are provided in Figure 33. The uppermost plot in Figure 33 compares the pumping rates for a scenario where only wells in the continuous coal seam are pumped (series layer 7b and layer 9b) and the medium hydraulic conductivity scenario described above (series layer 7a and layer 9a). As shown on the plot, the pumping rates are slightly higher when pumping only from the areas with continuous coal seams. The lower plot in Figure 33 shows the groundwater flux from the surficial layer into the active coal seam under this modified scenario. The groundwater flux increases slightly from 4.2x10"^ m^m^Vday to 4.4x10'^ m^m"^/day. Figure 33: Pilot Sca le Model - Zone Budget Medium K Pumping in Continuous Coal S e a m s Only Pumping Rates for wells situated in continuous Coal Seam 500 1000 Time (days) - Layer 7a - Layer 9a —•- - Layer 7b — * - - Layer 9b 1500 2000 Near Surface Groundwater Flux In Response to CBM pumping 6.0E-03 5.0E-03 — 4.0E-03 •>. n „E 3.0E-03 E. K 3 ^ 2.0E-03 1 .OE-03 O.OE+00 ;[)( )( )( ^ =ifc 0 200 400 600 800 1000 1200 Time (days) 1400 1600 1800 2000 Within Faults -Inactive Outcrops A Active Outcrops ! Groundwater flux would be a useful expression to estimate the loss of surficial groundwater in response to coal seam dewatering over the entire region i f the exposure of the coal seam were known. In the real system, the area of coal seam exposure is unknown so in any case it is difficult to accurately quantify groundwater losses from the surficial layer. Assuming the active coal seam's exposure to the unconformity is continuous across the region and using the geological map prepared by Swaren (1977), the total length of the layer 9 coal seam subcrop in the Merritt region is approximately 12 km. The layer 7 coal seam subcrop is slightly shorter than the layer 9 subcrop, at approximately 10 km. Table 9 provides a summary of the groundwater flux for each scenario and estimates the initial loss (before coal seam dewatering) and the total loss (during coal seam dewatering) from the surficial layer into active coal seams. Furthermore, Table 9 provides a comparison of the total loss during C B M production, to the average pumping rate of the City of Merritt production wells. The values provided for loss from the surficial layer are calculated using a total subcrop length of 22 km and a subcrop thickness of 10 m. Table 9: Groundwater F lux f rom Surf ic ia l ^ayer into active C o a Seams initial Flux ^/day) Peal< Flux (m^m' ^/day) Initial Loss (m^/day) Peak Loss (m^/day) Difference (m^/day) % Production Wells r l i g h K 4.20E-02 7.60E-02 9240.0 16720.0 7480.0 88.Q JMedium K 4.20E-03 7.50E-03 924.0 1650.0 726.0 8.9 L o w K 4.20E-04 7.40E-04 92.4 162.8 70.4 0.83 [Modified 4.20E-03 4.40E-03 924.0 968.0 44.0 0.5:^ It is important to note that the groundwater loss from the surficial layer to coal seam subcrops during C B M production is likely overestimated in Table 9. In the real system coal seams are likely not continuous because of pinch outs and low hydraulic conductivity faults. Also, a coal seam thickness of 10 m is likely an overestimate. Conversely, there are features of the real system that may act to produce an underestimate in Table 9. There could be high hydraulic conductivity faults, which were shown to affect the groundwater flux from surface layers, and jointing of the bedrock during bedrock deformation could introduce high hydraulic conductivity conduits for groundwater flow. Furthermore, past mining activities were not considered as part of this model. Abandoned coal mines act as very high hydraulic conductivity areas. Although it is unlikely that coal mining would influence the coal seams at the depth needed for C B M , abandoned coal mines may still play an important role as conduits for groundwater flow. To assess the validity of a boundary condition of a constant head boundary in layer 1, the total flux in Table 9 is compared to the estimated recharge. The recharge was estimated as 30 mm/year. Based on an area of 15,000,000 m^ the total recharge in the area is approximately 1,230 m^/day. The total flux from the High K and Medium K scenarios are above the total estimated recharge to the area. If this were the case, the total flux provided in Table 9 would represent an overestimate of the actual flux since the flow into the coal seam subcrop would be restricted by the available recharge. For the High K and Medium K scenarios, use of a constant head boundary in layer 1 provides model stability and is useful for simulating the upper bound of total flux, however, likely results in some overestimates of simulated flux into the coal seam subcrops. For the Low K and the modified scenarios, a constant head boundary condition in layer 1 is likely an accurate assumption. 9.3 Regional Scale Model The objectives of the regional scale model were to simulate regional scale C B M development and assess the role of a large regional scale fault on C B M development and regional groundwater flow. The regional scale C B M development was simulated for a duration of 50 years. The top of layer 3 represents the unconformity between the overlying Quaternary sediments and the Tertiary sedimentary rock. The response to coal seam dewatering was observed using the zone budget option in M O D F L O W for several cells in the fauh zone in layer 3. The model was used to examine high hydraulic conductivity, medium hydraulic conductivity and low hydraulic conductivity scenarios. Based on the results of the low hydraulic conductivity scenario, i f the hydraulic conductivity of the fault is lower than the surrounding geologic media it shows little to no response to C B M production. The low hydraulic conductivity scenario wi l l no longer be considered for the remainder of this section. Figure 34 shows the zone budget results of the regional scale model. As seen on the plots, groundwater flux along the unconformity increases as coal seam dewatering is initiated. It is not possible to make a reasonable estimate of the groundwater loss from the surficial layer to the fault since the width of the fault is not known. The length of the fault as it passes through the Tertiary sedimentary units is approximately 14 km. Table 10 estimates groundwater loss from the unconformity into a medium hydraulic conductivity and high hydraulic conductivity fault for three fault thicknesses. Initial Flux (m^m"^/day) Peak Flux (m^m"^/day) Initial Loss (m^/day) Peak Loss (m^/day) Difference (m^/day) % Production Wells Medium K (10m Thick) 1.24E-04 7.18E-04 17.4 100.6 83.2 0.98 Medium K (20m Thick) 1.24E-04 7.18E-04 34.8 201.1 166.4 1.97 Medium K (30m Thick) 1.24E-04 7.18E-04 52.2 301.7 249.5 2.95 High K (10m Thick) 1.24E-04 3.54E-03 17.4 495.3 477.9 5.66 High K (20m Thick) 1.24E-04 3.54E-03 34.8 990.5 955.7 11.31 iHigh K i30m Thick)^ 1.24E-04 3.54E-03 52.2 1485.8 1433.6 '^i:.!' ': 16.97 The values provided in Table 10 only describe the loss along the fault. In the real system there may be additional faults or other low hydraulic conductivity conduits for groundwater flow (i.e. abandoned mines) that would influence the groundwater loss from the surficial layers. Several assumptions were made when constructing the fault in the regional model. As such, the results provided in Table 10 are used only to assess the importance that the fault may play on the regional groundwater flow system. Figure 34: Groundwater Flux within Fault Zone along Unconformity Groundwater Flux along Unconformity In response to CBM Production Medium K Fault 1 .OE-04 O.OE+00 5000 10000 Time (days) 15000 20000 Groundwater Flux along Unconformity in response to CBM Production High K Fault n •D E 4.0E-03 3.5E-03 3.0E-03 2.5E-03 2.0E-03 1.5E-03 1.0E-03 5.0E-04 O.OE+00 5000 10000 Time (days) 15000 20000 10.0 SUMMARY AND CONCLUSIONS The Merritt region is characterized as having upland to lowland groundwater flow with a flow component parallel to the river valleys. This groundwater flow is directed towards the valley basin where the Merritt aquifer is located. The Merritt aquifer consists primarily of fluvially deposited sand and gravel ranging in thickness from 5 to 50 m; however, about 80 percent of the aquifer is interpreted to be less than 10 m thick. The area that is less than 10 m thick occurs mostly on the floodplain between the Coldwater and Nicola Rivers. The deepest part of the aquifer occurs along a trough that runs sub- parallel to the Coldwater River. The B C Ministry of Environment, Water Stewardship Division classified the Merritt aquifer as one of nine type " l A " aquifers in the province of B C . A type " l A " is considered to be a heavily developed, high vulnerability aquifer. Considering the importance of safe, clean groundwater, municipal and public concern and overall awareness of their groundwater supply is considered to be high. The main source of water to the surface that recharges to groundwater is precipitation. Precipitation varies both annually and seasonally and the average annual rainfall in the Merritt area is 322 mm/yr. The loss due to évapotranspiration was estimated to be 70 percent of the precipitation, while streamflow runoff accounted for 20 percent of precipitation and groundwater recharge was estimated at 10 percent of the precipitation. Five City of Merritt production wells pump groundwater from the trough area of the aquifer at a rate of approximately 100 L/s. Based on a groundwater flow model of the Merritt region using average pumping rates of the five City of Merritt production wells, the current groundwater demands do not deplete the system. Additional demands, such as increased pumping rates and additional production wells were not explored as part of this project. In order to better understand the response to coal seam dewatering two groundwater flow models were created. One model was used to simulate pilot scale C B M production for a duration of 5 years, while the second model was used to simulate regional scale C B M production for a duration of 50 years. The resuhs of the pilot scale model indicates that the effects of faults are not important to the groundwater flow in response to C B M production i f the hydraulic conductivity of the fault is lower than that of the surrounding geological media. If the hydraulic conductivity of the fault is higher than the surrounding media, groundwater may be drawn into faults from the surficial material. The amount of water that is drawn into the fault depends not only on the hydraulic conductivity of the fault, but also the extent to which the fault is exposed to the unconformity between the Tertiary rocks and the Quaternary sediments. At this time the extent of the exposure of the fault is not know and therefore it is difficult to meaningfully predict the quantity of groundwater that would be drawn into the fault in response to C B M production. The pilot scale model also assessed the role that coal seams subcropping along the unconformity between the Tertiary rocks and the Quaternary sediments has on the potential response to coal seam dewatering. Since the hydrostratigraphic properties of the various geological units are poorly understood, the model was used to examine high hydraulic conductivity, medium hydraulic conductivity and low hydraulic conductivity scenarios. In all cases the pumping rates for C B M wells was highest in areas close to subcrops and lowest in areas further away from subcrops and faults in relatively continuous coal seams. It was also found that i f C B M production were to only take place in the areas of relatively continuous coal seams, the groundwater flux into the faults and subcrops remains very small. However, under this scenario, the pumping rate in these areas increases slightly. The amount of water that is drawn into the subcrops depends not only on the hydraulic conductivity of the coal seams and the location and extent of the pumping well network, but also the extent to which the subcrop is exposed to the unconformity between the Tertiary rocks and the Quaternary sediments. The extent of the exposure of the subcrops is not know, however, a range of values were utilized to estimate the potential loss of groundwater from the surficial layers for the entire region under a regional scale C B M development scenario. The values range from approximately 7500 mVday loss for a high hydraulic conductivity scenario to approximately 70 m^/day for a low hydraulic conductivity scenario. As a comparison the City of Merritt production well pump approximately 8450 m^/day from the Merritt aquifer. For the medium hydraulic conductivity scenario the groundwater loss was 725 mVday, while in a system with the same parameter values, but under a modified scenario where coal seam dewatering takes place only in relatively continuous coal seams, the loss was approximately 45 m^/day. Based on the results of the model, it is unlikely that coal seam dewatering would have detrimental effects on the water supply in the area. In all scenarios the volumetric loss of groundwater from the surficial layer was less than the pumping rate of the City of Merritt production wells. Since it was determined that the city production wells are currently not depleting the system of groundwater, it is unlikely that removing a relatively small amount of groundwater from a portion of the catchment area would have any effect on the groundwater supply for the city. Furthermore, i f coal seam dewatering were to take place in relatively continuous coal seams, far from subcrops and high hydraulic conductivity faults, the volumetric groundwater loss is very low. The regional scale model assessed the role of a fault that extends from the southwest to the northeast through the region. The fault is interpreted to cut through the Tertiary rocks and three scenarios were simulated using the model to determine the importance the fault has on the regional groundwater flow in response to coal seam dewatering. The results of the regional scale model indicated that the effect of a low hydraulic conductivity fault is not important to the groundwater flow in response to C B M production. At this time the width and extent of the fault is not known; nevertheless, the groundwater loss into the fault was estimated along the unconformity between the Tertiary rocks and the Quaternary sediments for several different fault widths. For a 30 m wide high hydraulic conductivity fault, the estimated loss was approximately 1430 m^/day whereas for a 10 m wide medium hydraulic conductivity faults the estimated loss was 83.2 mVday. The resuhs provided as part of this study reflect the large degree of uncertainty incorporated into the various numerical models. In general the hydrostratigraphy of the Merritt region is poorly understood, however, additional investigation in the area would considerably constrain the results of further attempts at modeling the area. Based on the broad results of this study, in a well though out C B M development where C B M production takes place in areas relatively unaffected by faults, subcrops or other potentially high hydraulic conductivity features, the risk towards the City of Merritt's groundwater demands are likely to be low. However, as the city continues to develop and the groundwater demands increase, there is inherently greater risk to the groundwater supply. 11.0 FURTHER W O R K The major shortcomings of this study involve the lack of actual measurements of hydrostratigraphic properties of the various geologies. A n exploration program involving drilling boreholes and measuring the hydrostratigraphic properties including hydraulic conductivity and storage would greatly constrain the resuhs of the modeling. In order to predict gas and water production rates, the relative permeabilities of gas and water should be understood. If a drilling program were to take place, geochemical analysis groundwater of samples would be helpful to determine the age of the groundwater and determine possible source locations of the groundwater. Geochemical results could also provide an idea as to the quality of the groundwater and i f it would require special treatment and/or disposal in compliance with regulatory standards. Furthermore, a greater understanding of the properties and extent of faults in the region would limit the uncertainty involved in the role of faults on the regional groundwater flow. 12.0 REFERENCES B C Groundwater Consulting Services Ltd. (2006). Surface Water/Groundwater Interaction Study, Stage 1. Report submitted to the City of Merritt on March 27, 2006. B C Ministry of Environment Water Stewardship Division (1994). A n Aquifer Classification System for Ground Water Management in British Columbia. http://www.env.gov.bc.ca/wsd/plan_protect_sustain/groundwater/aquifers/Aq_Classificat ion/Ac|_Class.html. Bustin R M , Clarkson C R (1998). Geological Controls on Coalbed Methane Reservoir Capacity and Gas Content. International Journal of Coal Geology 38: 3-26. Cui W, Bustin R M , Dipple G (2003). Selective Transport of CO2, C H 4 , and N2 in coals: insights from modeling of experimental gas adsorption. Fuel 83: 293-303. Domenico P A , Schwartz F W (1998). Physical and Chemical Hydrogeology. John Wiley & Sons. E B A Engineering Consultants Ltd. (2002). Aquifer Protection Plan City of Merritt, B C . Report submitted to City of Merritt in December 2002. Fetter C W (2001). Applied Hydrogeology. Upper Saddle River, N.J . , Prentice-Hall. Freeze R A , Cherry JA (1979). Groundwater. Englewood Cliffs, N.J . , Prentice-Hall. Gilmar PC and Sharman K (1981). Report on Coal Licenses 6215 to 6242 Inclusive. Kamloops Division of Yale Land District, British Columbia; for Crows Nest Resources Ltd. Harrison S M (1995). The Hydrogeology and Hydrochemistry of a Potential Coalbed Methane Area, Elk River Valley, Southeastern British Columbia. A thesis presented to the University of Waterloo. JHP Coal-Ex Consuhing Ltd. (2002). Summary Report Merritt Coal - C B M Property. Report prepared for Forum Development Corp. on July 24. Johnson R C , Flores R M (1997). Developmental geology of coalbed methane from shallow to deep in rocky Mountain basins and in Cook Inlet - Matanuska basin, Alaska, U .S .A . and Canada. International Journal of Coal Geology 35: 241-282. Kaiser WR, Hamilton DS, Scott A R , Tyler R, Finley RJ (1994). Geological and hydrological controls on the producibility of coalbed methane. Journal of the Geological Society, London 151: 417-420. Kala Groundwater Consulting Ltd. (2004). Groundwater Potential Evaluation and test Well Siting Study City of Merritt, British Columbia. Report submitted to Urban Systems Ltd. on October 15,2004. Livingston E (1970). Letter to the City of Merritt discussing potential production well locations. Submitted August 31. McKee CR, Bumb A C (1987). Flow-Testing Coalbed Methane Production Wells in the Presence of Water and Gas. SPE (Society of Petroleum Engineers) Formation Evaluation 2:4: 599-608. Rice D D (1993). Composition and Origins of Coalbed Gas, A A P G Studies in Geology 38: 159-184. Ryan B (2003). Overview of the coalbed methane potential of Tertiary coal basins in the interior of British Columbia. British Columbia Ministry of Energy and Mines, Geological Fieldwork 2002. 2003-1: 1-23 Swaren R (1977). Merritt Coalfield, Preliminary Evaluation. Submitted to Imperial Oi l Ltd. Westwater Mining Ltd. (2003). Recommended Plan for Summer 2003 Exploration Programme at the Merritt Property (Freehold coal lands, D . L . 166, Merritt Coalfield). Report prepared for Forum Development Corp. January 13, 2003. APPENDIX A : K A L A FIGS AND CROSS-SECTIONS   CD APPENDIX B : HYDROLOGY DATA I Coldwater River Water L icenses Data provided by the BC Ministry of Environment, Water Stewardship Division No Purpose Licensee m^/s C025311 Waterworics Local Auth CITY OF MERRITT 4.38E-02 C026589 Waterworks Local Auth CITY OF MERRITT 6.57E-04 C030750 Waterworks Local Auth CITY OF MERRITT 2.03E-02 C030751 Watenworks Local Auth CITY OF MERRITT 2.03E-02 C053595 Irrigation WARAWA ALLAN T & MARY E 1.37E-05 C053596 Irrigation T H O M A N E K A N J E L I K A M 1.56E-05 C053597 Inrigation MISEK JIRI & ISABELLE H 7.53E-04 C110921 Irrigation STRANDE WILLIAM C 1.76E-03 CI10922 Irrigation PINE RANCH LTD 1.97E-03 CI17033 Conserv.-Use Of Water FISHERIES & O C E A N S CANADA 8.50E-02 CI18893 Irrigation LINDQUIST MICHELE C 3.11E-03 CI19905 Irrigation TAN JENNIFER C & LIM NORMAN C 3.91 E-04 C119906 Irrigation C O O K E MARILYN & LOUIS 4.30E-03 CI19907 Stock watering C O O K E MARILYN & LOUIS 2.19E-05 CI19907 Irrigation C O O K E MARILYN & LOUIS 4.50E-03 F009269 Irrigation KELLY OLIVER G & PATRICIA M 8.60E-04 FOI1229 Irrigation COLDWATER INDIAN BAND 3.91 E-04 FOI1230 Irrigation COLDWATER INDIAN BAND 8.02E-03 FOI1230 Irrigation COLDWATER INDIAN BAND 8.02E-03 F011230 Irrigation COLDWATER INDIAN BAND 8.02E-03 FOI1230 Irrigation COLDWATER INDIAN BAND 8.02E-03 FOI1230 Irrigation COLDWATER INDIAN BAND 8.02E-03 F015575 Irrigation DEVELOPMENT LTD 7.82E-04 F020032 Domestic T E R A S E N PIPELINES INC 4.38E-05 1 Licensed Quantity (m'̂ /s) 0.23 Upper Nicola River and Nicola Lake Water Licenses Data provided by the BC Ministry of Environment, Water Stewardship Division License No Purpose Licensee m'/s C054670 Domestic S E N G E R EDWARD & P A U U \ 2.19E-05 C110654 Irrigation COQUIHALLA DEVELOPMENTS 1.56E-02 C110654 Irrigation COQUIHALLA DEVELOPMENTS 1.56E-02 C110654 Irrigation COQUIHALLA DEVELOPMENTS 1.56E-02 C110654 Irrigation COQUIHALLA DEVELOPMENTS 1.56E-02 C110654 irrigation COQUIHALLA DEVELOPMENTS 1.56E-02 C110655 Irrigation COQUIHALLA DEVELOPMENTS 5.08E-02 C110655 Irrigation COQUIHALLA DEVELOPMENTS 5.08E-02 C110655 Irrigation COQUIHALLA DEVELOPMENTS 5.08E-02 C110655 Irrigation COQUIHALLA DEVELOPMENTS 5.08E-02 C110655 Irrigation COQUIHALLA DEVELOPMENTS 5.08E-02 C032982 Waterworks (Other) U P P E R NICOLA INDIAN BAND 4.38E-04 C065616 Irrigation U P P E R NICOLA INDIAN BAND 1.37E-03 C067293 Irrigation DOUGLAS LAKE CATTLE CO LTD 1.80E-03 C068392 Irrigation DOUGLAS LAKE CATTLE CO LTD 2.01 E-03 C068393 Irrigation DOUGLAS LAKE CATTLE CO LTD 2.34E-02 C068404 Irrigation DOUGLAS LAKE CATTLE CO LTD 1.51E-02 C068405 Irrigation DOUGLAS LAKE CATTLE CO LTD 2.00E-02 C068405 Irrigation DOUGLAS LAKE CATTLE CO LTD 2.00E-02 C068406 Irrigation DOUGLAS LAKE CATTLE CO LTD 4.1 OE-03 C068410 Irrigation DOUGLAS LAKE CATTLE CO LTD 1.02E-03 C068410 Stock watering DOUGLAS LAKE CATTLE CO LTD 1.10E-04 F006497 Incidental - Domestic QUILCHENA CATTLE CO LTD 2.19E-04 F006497 Irrigation QUILCHENA CATTLE CO LTD 1.78E-02 F006497 Incidental - Domestic QUILCHENA CATTLE CO LTD 2.19E-04 F006497 Irrigation QUILCHENA CATTLE C O LTD 1.78E-02 F006498 Incidental - Domestic QUILCHENA CATTLE CO LTD 2.19E-05 F006498 Irrigation QUILCHENA CATTLE CO LTD 2.11 E-03 F006499 Incidental - Domestic QUILCHENA CATTLE CO LTD 2.19E-05 F006499 Irrigation QUILCHENA CATTLE C O LTD 1.90E-03 F009600 Irrigation QUILCHENA CATTLE CO LTD 7.82E-03 F009600 Irrigation QUILCHENA CATTLE C O LTD 7.82E-03 FOI0822 Irrigation U P P E R NICOLA INDIAN BAND 1.86E-02 FOI0822 Irrigation U P P E R NICOLE INDIAN BAND 1.86E-02 F010822 Irrigation U P P E R NICOLA INDIAN BAND 1.86E-02 Fo i 1811 Irrigation U P P E R mCÙLA INDIAN SAND 6.84E-04 || Licensed Quantity (m^/s) 0.53 Nicola River Near Merritt Water L icenses Data provided by the BC Ministry of Environment, Water Stewardship Division License No Purpose Licensee m^/s C031416 Irrigation NEALE BROS RANCH 4.69E-03 C037183 Irrigation SCHOOL DISTRICT NO 58 3.91 E-04 C044011 Irrigation TURCHAK STEPHEN F & KELLY 3.91 E-04 C050394 Irrigation DOUGLAS LAKE CATTLE CO LTD 1.76E-03 C050394 Irrigation DOUGLAS LAKE CATTLE CO LTD 1.76E-03 C061110 Irrigation GARTHWAITE GORDON ET AL 3.92E-03 C061111 Irrigation GARTHWAITE GRETA A 5.08E-03 C063076 Irrigation BAKER J A M E S A 1.76E-04 C068316 Irrigation TELFORD JAMES 4.89E-03 C068317 Irrigation VICHERT B R U C E W 9.78E-04 C068656 Irrigation CHUTTER RANCH LTD 3.71 E-02 C068657 Stock watering CHUTTER RANCH LTD 3.72E-04 C068658 Irrigation CHUTTER RANCH LTD 1.52E-02 C068659 Irrigation CHUTTER RANCH LTD 5.18E-03 C068660 Irrigation CHUTTER RANCH LTD 8.54E-03 C068661 Irrigation CHUTTER RANCH LTD 1.49E-02 C068663 Stock watering CHUTTER RANCH LTD 2.19E-05 C068664 Stock watering CHUTTER RANCH LTD 2.19E-05 C109745 Conserv.-Stored Water DUCKS UNLIMITED (CANADA) 7,82E-04 C109745 Conserv.-Stored Water DUCKS UNLIMITED (CANADA) 7.82E-04 CI09746 Conserv.-Use Of Water DUCKS UNLIMITED (CANADA) 7.36E-03 CI09746 Storage DUCKS UNLIMITED (CANADA) 6.26E-04 CI18399 Irrigation BARTLETT C A R L E N N E & TED 1.70E-03 CI18420 Irrigation BARTLETT C A R L E N N E & TED 3.05E-03 F005669 Domestic NEALE BROS RANCH 2.19E-05 F005669 Irrigation NEALE BROS RANCH 9.38E-04 F008273 Irrigation GAVELIN WINNIFRED M 6.20E-03 F050528 Irrigation T O R G E R S O N GLEN & LOIS 2.82E-03 F051490 Irrigation SENIO TRACY A & KATHLEEN P 1.70E-03 F-i14234 In-igation PEACHEV JON 5.08E-03 Licensed Quantity (m^/s) 0.14 Hydrometric Station on Coldv^ater River (08LG010) Monthly Mean DIscliarge (m3/s) CD CD Year Jan Feb Mar 1 Apr May Jun Jul Aug Sep Oct Nov Dec Mean 1913 - - 31.3 42,8 12.4 1.47 - - - - 1 1914 - - 21.1 41,5 26,8 8.29 0.714 0.947 1.26 _ - _ 1915 - - - 17.6 15.6 6,65 2.08 0.685 0,266 3.77 4.12 2.42 _ 1916 - - - 202 - - 18.2 4.2 1,43 1.02 1.19 0.973 - 1917 0.85 0.85 1.13 2.61 28.2 37,7 15.2 2.34 0,987 1.24 - - - 1918 - - - - - 33.1 7.18 1.8 0,667 4.38 2.47 6.41 - 1919 - - 11.3 15.5 39.2 36,5 19.4 3.58 1.61 1,44 _ 1920 - - - 2.52 16.7 23.7 10.6 1.18 3,48 15.2 4.83 2.77 _ 1921 0.85 0.85 6.24 11.9 44.2 45,7 14.8 2.32 4,12 - _ _ _ 1961 - - - - 34.3 34.5 4.82 0.979 1,49 4,2 2,46 1.78 _ 1962 4.81 7.5 3.17 11.9 22,5 25,6 4,6 2,28 1,26 2,93 5.89 4.8 8.08 1963 2 19 10.9 5,35 7.01 23,3 17.2 6.99 223 1,12 3,13 5.29 7.02 7,62 1964 6.43 3.71 2.49 8.4 26,3 45.1 16.8 2.92 3.35 5.57 2.87 2.77 10,5 1965 2 3.14 3,64 10.8 25,8 23,1 5.23 1.49 0.885 2,59 4.5 3,37 7.21 1966 1.55 1.05 2 12.2 24,5 22,1 9.65 1,34 0,663 2,78 2.38 9,45 7.5 1967 3.31 2.75 2.08 3.44 28,9 43 7.72 1.19 0,306 4,56 6,61 3,1 8.92 1968 22 9.19 11,8 7.85 36,2 36,3 10.8 1.37 1,71 3,09 3.66 3,18 12.3 1969 252 2.44 2,14 9.65 39 19,4 3.04 0.651 1,9 3,33 3.5 4,28 7.68 1970 1.12 1.21 2.63 524 26.3 28.4 2,2 0.42 0,602 1,09 1,13 0,823 5,94 1971 1.99 5.2 2,88 9.05 57.6 35 14.4 2,23 1.14 1.93 2.19 0,576 11.2 1972 0.725 2.01 11,4 13.3 60.3 55,2 24.4 448 1.48 1.51 0,99 0,398 14,7 1973 0.603 0.934 1,67 4.68 23.8 16.3 4,83 0,632 0.38 1.88 2.47 2,45 5.08 1974 2 56 3.03 5,03 18.6 37 55.7 23.1 4,36 0.953 0.959 1,49 1,65 12,9 1975 1 23 1.23 1,39 5.08 33.3 45.9 16,2 1.95 1,12 2.48 9,66 9,36 10,8 1976 5.59 4.14 2.47 7.01 34.9 31.6 22.3 6,9 2,55 1,04 1.87 1.67 10.2 1977 1.88 3.26 2,07 7,94 14,5 14,1 1,93 0.434 0,648 1.12 3,98 3,53 4,6 1978 1.72 1.67 4,58 13.3 27,2 28.7 6.12 1,15 2,36 2.17 4.98 1.55 7.96 1979 1.31 1.25 3,08 6,65 24,3 14,6 2,45 0526 0,684 0.926 1,32 7,69 5.43 1980 1.86 2.09 2.9 14.7 29.3 18.3 4.06 1.73 2,06 2.14 4.48 18 8,49 1981 897 5.73 5,21 10,4 27,1 16.4 8,05 1.4 0,767 2.82 3,87 1,47 7,69 1982 1.4 2.31 2.2 3.95 30,1 43.4 11.8 1.98 0.986 2,07 1,55 1.56 8,62 1983 3.2 2.87 4,87 10,6 32.6 17.8 7,6 1.18 1,31 1.3 5,22 1,47 7,52 1984 10.8 2.74 3,46 5.36 10,2 24.8 8.69 1.6 1,44 2.16 1,69 1.04 6,16 1985 1.08 1.58 1.5 10,1 29,2 23.6 3,49 0.544 0,817 3.34 3,16 0,959 6.62 1986 2.06 4.68 9.74 12.1 283 25.5 5.19 1.15 0,806 1.46 3,24 1.93 8,01 1987 2 41 2.16 5.92 16,2 36 9 16.8 3,28 0.634 0,314 0.357 0 52 0664 7,21 1988 0.485 0.944 1.55 13.7 26,3 19.7 4.76 0.882 0.59 2.32 5,05 2,18 6,53 1989 2.11 2.28 2,26 12,7 31,9 24,2 3,69 2,01 0.981 2.41 9.84 6,68 8,44 1990 2.35 1.43 2.5 17.9 21 3 25.3 7.55 1.07 0,886 7 23.8 6,49 9,78 1991 3.13 15.5 6,97 17.6 36 29,8 14.5 3.05 1.81 1.16 4.22 2.66 11.3 1992 3.06 6.15 10,5 15,8 17.3 8,04 2.92 0.616 0.76 1.76 2.25 1.6 5,88 1993 0.996 1.24 2,86 6.46 25.9 9.01 3.79 2.43 1.07 1 1.2 1.51 4.82 1994 2,09 1.19 5,36 17,9 20,4 9.34 2.66 0.388 0.173 0.616 0.937 2.98 5.35 1995 1.55 6.64 5.1 9.98 35 - - - - - - - Mean 3,13 3.5 4.36 11 29,9 27.5 9,02 1.78 1.26 2.62 3.97 3.51 8,21 Hydrometric Station on Nicola River at outlet of Nicola Lake (08LG065) Monthly Mean Discharge (m^/s) Year Jan Feb Mar Apr May Jun Jul Aug Sep Oct Nov Dec Mean 1983 2.09 2,09 2.86 3,63 24,6 22.9 6.65 2,64 2.19 1,81 2.09 2.7 6.38 1984 2.89 2.43 2.18 3.01 9,84 33,7 11.1 2.79 1,78 1.23 1,08 0,992 6.07 1985 0.909 0,963 1,21 1.48 9,23 16.9 3,83 1,28 0,884 0.503 0.387 0.334 3.16 1986 - - - - - - 5.02 5,46 2.87 1.76 1.38 1,26 - 1987 1.17 1,18 1,22 1,57 13,8 4.3 2,01 1,53 1.71 1.18 1.04 0,528 2,62 1988 0.064 0.321 0,521 0,567 1,48 1,77 1,63 1,44 1.86 1.52 1,43 1.13 1.15 1989 0,905 0.88 1.03 2.69 7,37 11,8 5,37 4,54 3.81 2.73 2,43 2,35 3,84 1990 2.16 2.15 2.11 2.69 11,4 38.1 11.4 2.98 2.39 1.74 1.64 1.56 6.68 1991 1.44 1.51 1.54 2.82 24,9 24.6 12,2 3,99 3.33 2.49 2,36 1,94 6,96 1992 1.36 1.38 1.38 1,81 3,56 2.54 3,65 3,07 1.87 1.64 1.56 1,29 2,1 1993 1.2 1.19 1,22 2.14 19.7 11,8 10.2 16.5 3,55 3.21 3,1 3,08 6.47 1994 2.97 3.67 3.75 9,29 18 4,83 3,59 3,2 2,28 1.76 1.46 1,3 4,68 1995 1.29 1.33 1,37 5,38 19,5 17.8 7,36 3,23 2.95 2.5 2,32 2,37 5.64 1996 2.43 3.12 9.21 12.9 21,8 28,1 7,46 4,65 2.3 1.98 1.95 2 8,15 1997 2.06 3.35 8,5 10.6 42,8 29,4 16 7.62 3.44 3,28 4,38 4,82 11.4 1998 3.79 3,14 3.22 6,71 21,6 8.1 6,79 2,57 1,71 1,47 1.3 1 5,14 1999 0.987 0.916 1,17 6.04 24,8 25 15.2 4.42 2.3 2,4 2.2 2.02 7,32 2000 1,98 1.97 1.93 3,97 19.9 15,4 11,5 5,06 2,55 2.46 2,48 2,08 5.96 2001 1.86 1,78 1.69 1,74 7,25 9.13 3,81 3,24 2,64 1,95 1,74 1.4 3,19 2002 1.36 1.36 1,38 2,03 23.5 33,3 5,98 3,07 2.1 1,65 1.31 0.976 6.5 2003 0.864 0.827 0,835 0,912 1,58 2.17 2,95 2,28 1,78 1.42 1.27 0,894 1,49 2004 0.457 0.62 0.655 0,788 5.76 11.2 3.16 3,01 1.88 1,49 1.74 1.12 2,65 Mean 1.63 1,72 2,33 3,94 15,8 16,8 7,13 4,03 2.37 1.92 1,85 1.69 5,12 Hydrometric Station on Nicola River {08I-G007) Monthly Mean Discliarge (nf/s) Year Jan Feb Mar Apr May Jun Jul Aug Sep Oct Nov Dec Mean 1911 - - - - 19.2 7.85 5,22 2,64 2.42 2.41 - 1912 3.59 4.78 4.45 10.4 42.5 35.6 14.5 4,68 2,39 1,77 2,7 1.87 10.8 1913 0.923 2.46 2.38 7.26 37.4 49.8 14.3 4.18 3,1 4.27 2,74 1.01 10.8 1914 5.23 2.91 5.12 25.5 66.8 48.1 14.5 2,76 1,9 1,95 - - 1915 - - - 20.3 26.4 24 11.1 4.42 1,56 - - - 1957 _ - - - - - - - - - 3.18 - 1958 3.5 3.65 4.67 10.5 55.2 33.3 7.75 2.6 2,43 4,29 5.68 10.4 12.1 1959 7.37 4.43 5,81 14.4 55.1 78.3 27.6 6.48 6,33 11,1 12,7 10.9 20.1 1960 5.23 5.18 8.17 23.2 41.3 38.8 8.94 2.72 1.91 3,1 3.02 1.85 11.9 1961 346 5.18 4.52 13 52.5 59.1 10,1 2.9 2,04 4.72 3 2.47 13.6 1962 5.58 9.86 4.43 13.9 35.8 53.9 17.1 5.26 3,19 3,47 7.37 7.27 13.9 1963 335 13.7 7.44 9.13 28,4 27,3 13.5 6.27 4,19 6.02 7.05 8.49 11.2 1964 7.19 5.71 5.13 10.1 33.6 82.3 35.1 8.78 7,61 8,26 6.03 5.4 17.9 1965 4.71 8,05 7.83 16.2 40 45,6 12.9 6.57 2,5 4,36 6.46 4.6 13.3 1966 4.32 3.46 4.09 15.4 32.2 35.1 15.2 5,08 2,4 4.86 4.43 9 11.3 1967 5.64 4.32 363 4.67 38.1 98.4 17.4 3.84 1,76 6,66 11.7 5.74 16.8 1968 10.3 14.2 13.7 8.89 45.6 76.6 24.3 5.12 4,87 5,74 5.83 3.81 18.2 1969 2.35 4.55 4.73 12.2 68 41.6 11.4 5.01 4,31 5,79 4.55 3.55 14.1 1970 2.97 3.12 3.91 5.85 35.2 43.4 8.52 3.62 2,69 2,55 1.61 1.33 9.57 1971 2.62 8.05 4.06 10.1 87.5 90.7 33.3 5.3 2,77 2.98 3.45 2.94 21.2 1972 2.32 2.57 15 23 87.6 95,6 47.1 13.1 5,32 2,9 0.843 1.9 24.8 1974 4.25 4.84 6,36 19.5 62.1 90.8 41.5 10.4 4.14 3.24 3.59 3.57 21.2 1975 2.85 3.26 4.44 8.7 40.5 64.2 22.8 6 3,32 4,29 12.1 9.71 15.2 1976 6.51 5.57 4.35 8.48 41.3 46 25,3 13.4 12.3 5.65 5.25 3.75 14.8 1977 3.54 5.37 4.03 9.26 23.2 20 5.24 2.19 2,04 2,49 4.69 3.89 7.15 1978 2.57 2.42 6.25 15 462 50.5 12.4 3.9 5.12 4,8 7.5 3.5 13.4 1979 3.03 3.46 6.24 7.77 37.9 25.3 6.56 2.55 2,38 2,18 1.81 6.85 8.87 1980 2.21 2.56 4.25 14.7 31.1 30.5 8.4 3.8 4.97 4,04 5.98 20.2 11.1 1981 106 7.56 7.25 11.1 41.8 38.2 19.9 6.57 4.21 5,76 6.18 4.8 13.7 1982 5.29 5.96 5.61 6.72 46.5 66.1 28.3 10.3 5.01 5,32 4.11 4.47 16.2 1983 5.98 5.82 8.64 15.1 61.2 41.2 14.5 4.3 4.07 3,32 6.68 4.23 14.6 1984 14.4 5.79 5.95 8.57 19.7 61.6 18.7 4.8 3,71 4,17 3,49 2,53 12.8 1985 2.57 3.05 3.34 11.4 36.7 38 7.18 2.04 231 4,27 3.61 1.44 9.67^ 1986 2.75 5.28 13.6 13.5 33.4 41.7 11.3 7.34 4.75 4,6 5,02 3,56 12.2 1987 4.14 3,96 7.82 17.4 47.8 19.6 5.75 2.73 2.52 2,02 2,07 1.54 9.82 1988 0.996 1.66 2.43 13.1 25.2 19 6.88 2.5 2.61 4,4 6,77 3,77 7.45 1989 3.36 3.58 3.99 14.3 36.8 33.2 9.54 7.33 5.53 5,81 12,1 10.4 12.2 1990 5.13 3.48 5.33 19.7 33.1 67.7 20.6 4.63 4.12 9,48 25,9 9,33 17.4 1991 524 19.3 9.5 23.1 646 59 29.2 7.84 5.61 4,4 7,4 5.5 2d 1992 5.18 8.49 13.1 20.1 22.9 11.6 7.63 4.33 3.25 4,06 4,32 3,05 1993 2.65 3.12 4.73 9.52 45.9 23.8 17.3 22 5,79 5,39 5,02 5.6 12.7 1994 5.57 5.34 9.28 29.9 40.5 15.8 6.62 3.85 2.83 3,11 3,01 4.55 lO.d 1995 3.12 8.12 7.16 16 55 35.1 11,5 5.86 4,12 6,8 22,6 13.4 15.8 1996 10.3 11.1 21.4 39.9 46.1 53 14.8 6.13 3.5 4,7 7,39 3.39 18.4 1997 3.66 9.55 16.7 31.7 955 63 28.1 10.1 6.28 9,86 10,6 6.97 24.4 1998 6.78 6.03 7.32 15.8 54.8 23.7 10.7 3.4 2.48 2,67 4,39 4.85 12 1999 5.44 4.26 4.72 17.4 58.6 69.2 41.8 11.4 5.13 5,91 12,8 6.99 20.4 2000 4.88 4.74 4.59 15.7 40.6 37.5 17.7 6.96 4.8 5,57 5,66 3.81 12.7 2001 3.52 2.9 4.06 7.76 25.8 21.2 7.12 4.36 3.35 3,55 6,78 4.03 7.89 2002 7.63 4.21 4.28 13.4 57.7 73.8 19.9 5,21 3.25 3,08 3,93 2.95 16.6 2003 3.27 3.84 4.96 11 21.1 19.2 5.07 2.6 223 11,6 4,57 2.98 7.72 2004 2.72 2.79 5.99 15.7 25.8 22.3 4.62 3.22 4.29 3,69 7,82 9.7 9.05 Mean 4.71 5.58 6.67 14.7 44.6 46.8 16.7 5.85 3,89 4,75 6,42 527 13.9 APPENDIX C : CHEMISTRY RESULTS / V L S Enuiranmental CHEMICAL ANALYSIS R E P O R T Date: A L S File No. Report O n : Report T o : Attention: Received: A u g u s t 15, 2 0 0 5 W 1 9 4 9 r Merritt W a t e r A n a l y s i s U B C - Earth & Ocean Sc iences G e o p h y s i c s 6 3 3 9 S t o r e s R o a d V a n c o u v e r , B C V 6 T 1Z4 Mr. Jordin Barclay Ju l y 2 2 , 2 0 0 5 A L S E N V I R O N M E N T A L per: I A L S C A N A D A L T D , 1988 Tr iumph Street, Vancouver . B C C a n a d a V 5 L 1K5 P h o n e : 604-253-«le8 Fax : 604-253-6700 W e b s i t e : www.a lsenv i rocom File No . W 1 9 4 9 r R E M A R K S This report, A L S file W1949r, supersedes the previous file W1949. The Dissolved Potassium was re-analyzed for samples previously showing result of less than 2.0 milligrams per litre. Sample ID SPRING 1 SPRING 2 DWW 1 DWW 2 DWW 3 Sample Date Sample Time ALS ID 05-07-21 16:00 1 05-07-20 13:00 2 05-07-20 15:00 3 05-07-21 17:00 4 05-07-21 13:00 5 Dissolved Anions Alkalinity-Total C a G 0 3 301 324 228 289 194 Bromide Br <0.050 <0.50 <0.050 <0.050 <0.050 Chloride CI 33.7 5.1 0.79 2.21 3.73 Fluoride F 0.116 <0.20 0.199 0.498 0.089 Sulphate S 0 4 28.6 994 38.2 77.3 44.1 Nutrients Nitrate Nitrogen N 0.269 <0.050 <0.0050 0.0673 0.0269 Nitrite Nitrogen N 0.0015 <0.010 <0.0010 <0.0010 <0.0010 Sample ID SPRING 1 SPRING 2 DWW 1 DWW 2 DWW 3 Sample Date 05-07-21 05-07-20 05-07-20 05-07-21 05-07-21 Sample Time 16:00 13:00 15:00 17:00 13:00 ALS ID 1 2 3 4 5 Dissolved Metals Aluminum D-AI <0.20 Antimony D-Sb <0.20 Arsenic D-As <0.20 Barium D-Ba 0.113 Beryllium D-Be <0.0050 Bismuth D-Bi <0.20 Boron D-B <0.10 Cadmium D-Cd <0.010 Calcium D-Ca 95.6 Chromium D-Cr <0.010 Cobalt D-Co <0.010 Copper D-Cu <0.010 Iron D-Fe <0.030 Lead D-Pb <0.050 Lithium D-Li <0.010 Magnesium D-Mg 31.8 Manganese D-Mn <0.0050 Molybdenum D-Mo <0.030 Nickel D-Ni <0.050 Phosphorus D-P <0.30 Potassium D-K 1.51 Selenium D-Se <0.20 Silicon D-Si 7.57 Silver D-Ag <0.010 Sodium D-Na 13.1 Strontium D-Sr 0.365 Thallium D-TI <0.20 Tin D-Sn <0.030 Titanium D-Ti <0.010 Vanadium D-V <0.030 Zinc D-Zn 0.0168 <0.20 <0.20 <0.20 <0.20 <0.20 <0.20 <0.20 <0.20 <0.20 <0.20 <0.20 <0.20 <0.010 0.061 0.038 0.051 <0.0050 <0.0050 <0.0050 <0.0050 <0.20 <0.20 <0.20 <0.20 0.14 <0.10 <0.10 <0.10 <0.010 <0.010 <0.010 <0.010 301 62.6 84.7 50.9 <0.010 <0.010 <0.010 <0.010 <0.010 <0.010 <0.010 <0.010 <0.010 <0.010 <0.010 <0.010 0.604 0.341 0.039 <0.030 <0.050 <0.050 <0.050 <0.050 0.023 <0.010 <0.010 <0.010 66.5 31.3 34.2 19.5 1.09 0.0466 0.0081 <0.0050 <0.030 <0.030 <0.030 <0.030 <0.050 <0.050 <0.050 <0.050 <0.30 <0.30 <0.30 <0.30 2.2 1.99 1.84 1.63 <0.20 <0.20 <0.20 <0.20 6.49 15.0 8.16 7.71 <0.010 <0.010 <0.010 <0.010 121 22.8 17.9 17.3 6.76 0.466 0.607 0.436 <0.20 <0.20 <0.20 <0.20 <0.030 <0.030 <0.030 <0.030 <0.010 <0.010 <0.010 <0.010 <0.030 <0.030 <0.030 <0.030 <0.0050 <0.0050 0.173 0.0175 Water DWW 1 DWW 1 05-07-20 Q C # 15:00 453112 Dissolved Anions Alkalinity-Total C a C 0 3 228 226 Bromide Br <0.050 <0.050 Chloride CI 0.79 0.80 Fluoride F 0.199 0.198 Sulphate S 0 4 38.2 38.4 Nutrients Nitrate Nitrogen N <0.0050 <0.0050 Nitrite Nitrogen N <0.0010 <0.0010 Water DWW 1 DWW 1 05-07-20 Q C # 15:00 453112 Dissolved Metals Aluminum D-AI <0.20 <0.20 Antimony D-Sb <0.20 <0.20 Arsenic D-As <0.20 <0.20 Barium D-Ba 0.061 0.060 Beryllium D-Be <0.0050 <0.0050 Bismuth D-Bi <0.20 <0.20 Boron D-B <0.10 <0.10 Cadmium D-Cd <0.010 <0.010 Calcium D-Ca 62.6 63.0 Chromium D-Cr <0.010 <0.010 Cobalt D-Co <0.010 <0.010 Copper D-Cu <0.010 <0.010 Iron D-Fe 0.341 0.342 Lead D-Pb <0.050 <0.050 Lithium D-Li <0.010 <0.010 Magnesium D-Mg 31.3 31.3 Manganese D-Mn 0.0466 0.0465 Molybdenum D-Mo <0.030 <0.030 Nickel D-Ni <0.050 <0.050 Phosphorus D-P <0.30 <0.30 Selenium D-Se <0.20 <0.20 Silicon D-Si 15.0 15.1 Silver D-Ag <0.010 <0.010 Sodium D-Na 22.8 22.9 Strontium D-Sr 0.466 0.464 Thallium D-TI <0.20 <0.20 Tin D-Sn <0.030 <0.030 Titanium D-Ti <0.010 <0.010 Vanadium D-V <0.030 <0.030 Zinc D-Zn <0.0050 <0.0050 File No . W 1 9 4 9 r Appendix 2 - M E T H O D O L O G Y Outlines of the methodologies utilized for the analysis of the samples submitted are as follows Alkalinity in Water by Colourimetry This analysis is carried out using procedures adapted from E P A Method 310.2 "Alkalinity". Total Alkalinity is determined using the methyl orange colourimetric method. Recommended Holding Time: Sample: 14 days Reference: A P H A For more detail see A L S Environmental "Collection & Sampling Guide" Dissolved Anions in Water by Ion Chromatography This analysis is carried out using procedures adapted from A P H A Method 4110 "Determination of Anions by Ion Chromatography" and E P A Method 300.0 "Determination of Inorganic Anions by Ion Chromatography". Anions are determined by filtering the sample through a 0.45 micron membrane filter and injecting the filtrate onto a Dionex lonPac A G I 7 anion exchange column with a hydroxide eluent stream. Anions routinely determined by this method include: bromide, chloride, fluoride, nitrate, nitrite and sulphate. Recommended Holding Time: Sample: 28 days (bromide, chloride, fluoride, sulphate) Sample: 2 days (nitrate, nitrite) Reference: A P H A and E P A For more detail see A L S Environmental "Collection & Sampling Guide" Metals in Water This analysis is carried out using procedures adapted from "Standard Methods for the Examination of Water and Wastewater" 20th Edition 1998 published by the American Public Health Associat ion, and with procedures adapted from "Test Methods for Evaluating Solid Waste" SW-846 published by the United States Environmental Protection Agency (EPA). The procedures may involve preliminary sample treatment by acid digestion, using either hotplate or microwave oven, or filtration (EPA Method 3005A). Instrumental analysis is by atomic absorption/emission spectrophotometry (EPA Method 7000 series), inductively coupled plasma - optical emission spectrophotometry (EPA Method 601 OB), and/or inductively coupled plasma - mass spectrometry ( E P A Method 6020). Recommended Holding Time: Sample: 6 months Reference: E P A For more detail see: A L S "Collection & Sampling Guide" File No . W 1 9 4 9 r Appendix 2 - IVIETHODOLOGY - Continued Results contained within this report relate only to the samples as submitted. This Chemical Analysis Report shall only be reproduced in full, except with the written approval of ALS Environmental. End of Report

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