COMPLETION REPORT GROUNDWATER STUDY AT DEEP BAY WATERWORKS DISTRICT

Transcription

1 PROJECT NUMBER D COMPLETION REPORT GROUNDWATER STUDY AT DEEP BAY WATERWORKS DISTRICT Prepared for: DEEP BAY WATERWORKS DISTRICT R.R. 1, Site 150, C4 BOWSER, B.C. V0R 1G0 Prepared by: PACIFIC HYDROLOGY CONSULTANTS LTD West 8th Avenue VANCOUVER, B.C. V6J 1T5 MARCH 29, 2007

2 PACIFIC HYDROLOGY CONSULTANTS LTD. Consulting Hydrogeologists Suite 201,1537 West 8' Avenue, VANCOUVER, B.C. V6J 1T5 Telephone: (604) Facsimile: (604) Website: www. ~hcl.ca March 29,2007 Deep Bay Waterworks District R.R. 1, Site 150, C4 BOWSER, B.C. VOR 1GO Attention: Dr. Ian Birtwell Subject: Completion Report Groundwater Study at Deep Bay Waterworks District Dear Sirs: We herewith provide our completion report regarding groundwater study at Deep Bay. Please do not hesitate to contact us if there are questions about the report or if we can be of further assistance with the subject of this report. Yours truly, PACIFIC HYDROLOGY CONSULTANTS LTD. Carol Ma Junior Hydrogeologist Ed Livingston, P. Eng. Manager

3 Completion Report Groundwater Study for Deep Bay Waterworks District Page i COMPLETION REPORT GROUNDWATER STUDY AT DEEP BAY WATERWORKS DISTRICT CONTENTS Section Subject Page LETTER OF TRANSMITTAL... i EXECUTIVE SUMMARY...v 1.0 INTRODUCTION Purpose and Scope Authority Background Acknowledgements GEOLOGY AND HYDROGEOLOGY Geology Hydrogeology HYDROGEOLOGICAL INVESTIGATION General Hydrographs of Provincial Observation Wells No. 310 and Discussions Results Monthly Operation / Maintenance Reports Discussions Results Well Capacity Ratings and Performances Well Interference at Deep Bay Well Field TOTAL WELL CAPACITY GROUNDWATER QUALITY EMERGENCY WATER SUPPLY SUMMARY AND CONCLUSIONS RECOMMENDATIONS...22 Pacific Hydrology Consultants Ltd.

4 Completion Report Groundwater Study for Deep Bay Waterworks District Page ii CONTENTS (cont'd) APPENDICES APPENDIX A APPENDIX B AREA AND WELL LOCATION MAPS SUMMARY TABLE OF SELECTED DETAILS AT DEEP BAY AREA APPENDIX C DEEP BAY WATEROWRKS DISTRICT OPERATIONS / MAINTENANCE REPORTS APPENDIX D APPENDIX E DATA SPREADSHEET AND PLOTS GROUNDWATER QUALITY TABLE AND LABORATORY REPORTS FIGURES Number Title Page Figure 1 Area Location and Regional Topography A 1 Figure 2 Water Well Locations A 1 Figure 3 Hydrograph of Provincial Observation Well No Figure 4 Hydrograph of Provincial Observation Well No Figure 5 Figure 6 Figure 7 Figure 8 Figure 9 Hydrograph of Observation Well No. 331 During the Period May 31 to September 6, Hydrograph of Observation Well No. 331 During the Period May 31 to June 30, Monthly Consumption at Deep Bay Waterworks District During the Period January 2004 to October 2006 D 2 Average Pumping Rate at Deep Bay Waterworks District During the Period January 2004 to October 2006 D 3 Average Daily Water Use for Connection at Deep Bay Waterworks District During the Period January 2004 to October 2006 D 4 Pacific Hydrology Consultants Ltd.

5 Completion Report Groundwater Study for Deep Bay Waterworks District Page iii CONTENTS (cont'd) TABLES Number Title Page Table 1 Selected Details of Deep Bay Waterworks District Production Wells B 1 to and Provincial Observation Wells No. 310 and 331 B 3 Table 2 Average Daily Use per Connection for the Period 2004 to 2006 in the Deep Bay Waterworks District Water System 11 Table 3 Pumping Rates of Wells in Deep Bay Waterworks District Water System 13 Table 4 Performances of Wells in Deep Bay Waterworks District System 13 Table 5 Deep Bay Waterworks District Monthly Water Production and Use D 1 Pacific Hydrology Consultants Ltd.

6 Completion Report Groundwater Study for Deep Bay Waterworks District Page iv EXECUTIVE SUMMARY Investigation of the groundwater availability at Deep Bay was initiated in mid2006 on a request by Deep Bay Waterworks District (BDWD) to determine whether: 1. there will be sufficient water to supply the existing system under extreme drought conditions; and, 2. the groundwater quality of the Deep Bay aquifer complexes has been changed over the years. As shown on the hydrographs of Provincial Observation Wells No. 310 and 331, the water levels in the two wells behave in slightly different manners; the annual lows in Well No. 310 occur in the October/November period and highs in late February, whereas the lows in Well No. 331 usually occur in the late August/early September period and highs in late January. The lowerthanaverage water levels in both wells throughout the years 2000 to 2002 were mainly due to the belowaverage total precipitation, which resulted in a long drought period. Since January 1990, when Well No. 310 was established, the hydrograph from the well shows that there have been three drought periods late 1980's ending in 1991, 1993 to 1994, and, 2000 through about Following the severe drought in the 2000 and 2002 period, the water levels in both Wells No. 310 and 331 have recovered, although not yet to their predrought conditions. The monthly record sheets prepared by Mr. Dennison of Deep Bay Water District from the period January 2004 to October 2006, are effective in showing for each month, the actual production of water from each well and the total running time for each well pump. From these data, average pumping rates have been calculated. Based on the data sheets, we conclude that there has been a significant decrease in the amount of water pumped in the maximum months of withdrawal of each year over the past three years, following the installation of water meters on the existing system, and perhaps also the repairs of leaks in the system. The reduction from 2004 to 2006 is about 50%, when the number of connections increased from 525 to 550. The estimated total inhouse water use for the past three years has remained almost constant, at about 2 million igal/month. The performances of the seven operating wells have been evaluated based on a 10minute pumping test on each well, except Wells 585 and 897, which were pumped simultaneously for more than 3 hours. Following the evaluation, there is no obvious evidence showing that the performance of any of the operating wells has decreased significantly since the wells were installed. Pacific Hydrology Consultants Ltd.

7 Completion Report Groundwater Study for Deep Bay Waterworks District Page v In general, the actual pumping rates during the year 2006 were more or less the same as the original ratings, except for Well 585 which was rated at 7.42 Lps (98 igpm), but is now pumping at 10.1 Lps (134 igpm); the reason(s) for this increase may be one or more of the following: 1. the water meter may be reading too high; 2. the well may have undergone additional development with use, resulting in increased well capacity; and/or, 3. the highrate pumping may be using more than the 70% of the total available drawdown on which the rating was based. In any case, it will not damage the well. Groundwater flow regimes are dynamic. The analysis of data from our previous reports and records of use show that the shallow sand aquifer at Deep Bay acts as a conduit for continuous groundwater flow from the recharge area to the discharge area and eventually into the sea. At Deep Bay, the aquifer is not an underground storage reservoir, which is drained by natural discharge and/or by pumping from wells, in this case, from the DBWD wells. The static water levels in the production wells are maintained by the groundwater flow through the aquifer complex, which is similar to the level of water in a stream maintained by flow in a stream. Under the hydrologic conditions at Deep Bay, reducing groundwater consumption has no significant effect on the amount of water which is flowing through the groundwater flow systems. Although the lower water levels in the Deep Bay aquifer complex during a drought period reduces the total available drawdown of the DBWD wells, thereby reducing their capacities, the excess of the total well capacity of the existing DBWD system, especially because the wells are spread out across the direction of groundwater flow, makes it possible to maintain the capacity of the system to meet the water demands at Deep Bay. The decrease in the total capacity of the system is expected to be small under severe drought conditions, given the high total capacity of the seven DBWD operating wells. This was demonstrated during the summer of 2006 when the water demand was higher than usual but only two of the wells, Wells 585 and 8 97, were in production for most of the summer period, with periodic use of Well 690 as a supplementary water supply. Based on the review of several laboratory reports for samples from the two Observation Wells and four (Wells 177, 369, 690 and 897) of the seven BDWD operating wells, we believe that the chemical quality of the waters from these wells has not changed significantly over the past 13 years. Pacific Hydrology Consultants Ltd.

8 Completion Report Groundwater Study for Deep Bay Waterworks District Page vi With the present management methods and procedures, the existing DBWD system is being managed very well. We recommend that the systematic collection of data on water production and pumping hours and pumping rates of all wells be continued and that the data be analyzed, preferably on an annual basis, so it is possible to quickly determine whether there are any changes in well performance that would reduce individual well capacity, whether the pump in any well is performing properly, or whether both pump and well performance in any well may have declined. Systematic collection of such data is particularly important in view of the local hydrogeology. Pacific Hydrology Consultants Ltd.

9 Completion Report Groundwater Study for Deep Bay Waterworks District Page INTRODUCTION 1.1 Purpose and Scope Concerns about available groundwater supplies for the existing Deep Bay Waterworks District (DBWD) water system under severe drought conditions have been raised by the local residents at Deep Bay, located 25 km northwest of Qualicum Beach on the eastern part of Vancouver Island, B.C. In order to better understand the present hydrogeological conditions at Deep Bay, studies have been carried out by a community team and McElhanney Engineering & Consulting with focus on a drought management plan and computer modeling of groundwater withdrawal. As part of the groundwater study, Pacific Hydrology Consultants Ltd. (PHCL) has been engaged to provide hydrogeological consulting services for groundwater assessment at Deep Bay. This report by PHCL has been prepared to: 1. Assemble and review all relevant background information on the current DBWD situation. The background information includes the following: a) Water level data (up to date as of January 2007) for the hydrographs of the Provincial Observation Wells No. 310 and 331, which were obtained from Ministry of Environment (MoE) website and the DBWD office. b) Monthly water pumping records, monthly total pumping hours, number of the production wells in operation each month starting in January 2004, all of which were provided by the DBWD office. c) Monthly precipitation records since1980 from the Comox Airport, located about 80 km northwest of Deep Bay. d) Drought Management Plan, which was prepared in 2005 specifically for the conditions at Deep Bay. The report on drought management in the Deep Bay area was forwarded to PHCL by DBWD. e) Chemical analyses of groundwater from Provincial Observation Well No. 310 of 1993, 1996 and 2001 and Well No. 331 of 1996, 1998 and 2006, which were obtained from the Ministry of Sustainable Resource Management website. 2. Assemble and analyze the performance of each of the seven production wells by means of 10 minute pumping tests on November 1, to determine the present specific capacity of each well and, if possible, compare it with the specific capacity determined for each well at the time of its completion and with that presented in PHCL's 1997 report. Pacific Hydrology Consultants Ltd.

10 Completion Report Groundwater Study for Deep Bay Waterworks District Page 2 3. Based on the present specific capacity, determine whether or not the performance of any of the seven production wells has significantly decreased. 4. Provide recommendations as to operation and management of the DBWD production wells. The area location and regional topographic setting of Deep Bay are shown on Figure 1 in Appendix A (Page A 1); Figure 2 (Page A 2) is a 1:5,800 scale plan, which shows the approximate locations of the seven production wells at Deep Bay, along with the two provincial observation wells. We note that, except Wells 173, 273, and 369, all wells are located in a well field on the south side of the Island Highway. Both Figures 1 and 2 are taken from PHCL's 1998 report and have been slightly modified by PHCL for this report. 1.2 Authority PHCL was invited by DBWD, in a facsimile request dated May 3, 2006 on the subject "Review of Well Pumping Capacities during Drought Conditions," to provide hydrogeological consulting services for review and comment on groundwater issues during drought conditions. PHCL's reply as a proposal, which was contained in a letter dated May 17, 2006, titled "Provision of Hydrogeological Consulting Services to Carry out Several Pump Tests of the Deep Bay System by Using All of the Production Wells," was accepted. PHCL was informed in a telephone discussion that DBWD had authorized PHCL to proceed with the course of investigations outlined in our letter of proposal. However, due to our understanding of the present situation at Deep Bay during our site visit in October/November, 2006, the investigation was carried out mostly in accordance with PHCL's letter of proposal dated May 17, 2006; the tasks involved in the investigation are tasks 1, 2, 5 (partly) and 6 outlined under 4.1 of our May 17, 2006 letter. 1.3 Background Published documents and information that have been reviewed for the preparation of this report include the following: 1. N.T.S. Map Sheet 92F/7, Horne Lake, of scale 1:50,000 and contour interval of 20 m. 2. Hydrographs for both Provincial Observation Wells No. 310 and 331 (data available up to January 2007) from the Ministry of Environment (MoE) website and the District Office. 3. Monthly precipitation records from the Environment Canada website, at the Comox Airport, which cover the period 1980 to Pacific Hydrology Consultants Ltd.

11 Completion Report Groundwater Study for Deep Bay Waterworks District Page 3 4. Drought Management Plan for DBWD dated March 2005, which was prepared by a community team composed of Mr. Bon Thorburn, P. Eng., of Thorconsult Ltd., Mr. James Hooper, Ph.D., Physical Geographer, Mr. Richard Wahlgren, owner/manager of Streamside Native Plants and Ms. Dianne Eddy, elected Trustee of DBWD. 5. correspondences and telephone discussions covering the period October 2006 to January 2007 between Dr. Ian Birtwell and Mr. Jim Dennison of DBWD, and, Ed Livingston and Carol Ma, of PHCL. 6. Geological Survey of Canada Map 1111A, Surficial Geology, Horne Lake, Vancouver Island, British Columbia, of scale 1" to 1 mile; J.G. Fyles, 1963, Geological Survey of Canada. Reports contained in PHCL's files covering past work on groundwater exploration and potential issues in the Deep Bay area, have also been reviewed and considered for this project. Our previous reports are listed as follows: 1. Completion Report on "Construction and Testing of Production Well No. 5 Deep Bay Waterworks District," dated June 21, Report on "Selection of a Site for Proposed Well No. 6 for Deep Bay Waterworks District," dated February 27, Completion Report on "Construction and Testing of Deep Bay Waterworks District Well No. 6," dated December 27, Report on "Groundwater Supply Potential in the Southwest Corner of D.L. 28, West of the Island Highway at Deep Bay," dated December 20, Report on "Evaluation of Maximum Groundwater Potential from Wells in the Southwest Corner of D.L. 28, West of the Island Highway at Deep Bay," dated August 15, Report on "Evaluation of Results of Test Drilling & Performance Testing of Well 796 on D.L. 28, West of the Island Highway at Deep Bay," dated June 4, Report on "Implication of October 1996 Aquifer Test of Deep Bay Wells Installed within D.L. 28, West of the Island Highway to the Installation of Additional Production Wells," dated March 31, Pacific Hydrology Consultants Ltd.

12 Completion Report Groundwater Study for Deep Bay Waterworks District Page 4 8. Completion Report on "Installation & Testing of Well 897 and ReEvaluation of Groundwater Supply Potential of Quadra Sand & Aquifer at Deep Bay," dated November 25, Progress Report on "Groundwater Study for Deep Bay," dated January 8, Discussions with Mr. Jim Dennison and Dr. Ian Birtwell, both of DBWD, during our 2day trip to Deep Bay on October 31 were also considered. 1.4 Acknowledgements The discussions with Dr. Ian Birtwell, member of Water Board of DBWD, were essential to understanding the present situation at Deep Bay in regard to groundwater issues; his interest in this project and assistance is hereby acknowledged. Acknowledgement of the cooperation and assistance of those individuals identified below contributed to PHCL's ability to carry out the study covered by this report, is also hereby given: Mr. Jim Dennison, Maintenance Operator, for providing monthly operations/maintenance reports on all DBWD Wells and Provincial Observation Wells No. 310 and 331, which cover the period January 2004 to October 2006, and assisting PHCL to carry out a 10minute pumping test on each of the seven operating wells at Deep Bay on November 1, Ms. Cindy Van Vliet, Secretary of DBWD, for providing recent laboratory analytical reports of groundwater from four (Wells 173, 273, 369 and 897) of the seven DBWD wells. 2.0 GEOLOGY AND HYDROGEOLOGY 2.1 Geology The hydrogeology of the aquifer complexes at Deep Bay has been discussed several times in PHCL's previous reports during the investigation of potential additional groundwater development since " the Deep Bay Production Wells intercept water which is in motion in a groundwater flow system which is recharged inland at higher topographic elevation and which is in constant motion toward the discharge end of the flow regime at the sea, where groundwater is continuously discharging into the sea below sea level. Along the path of groundwater flow, some discharge takes place to streams and springs, with stream base flow during the summer drought maintained Pacific Hydrology Consultants Ltd.

13 Completion Report Groundwater Study for Deep Bay Waterworks District Page 5 by such groundwater discharge. Despite the fact that most recharge to the groundwater flow regime occurs from precipitation in winter and early spring, because the flow system within the Quadra Sands Aquifer is several kilometres in length, and because the permeability of the sand is moderate to high, groundwater flow tends to be fairly uniform in spite of the fact that recharge to the flow system occurs during only part of the year (PHCL's November, 1997 Report)." 2.2 Hydrogeology From available information and from our understanding of and experience with, groundwater flow, it is our opinion that the ground flow regime contained within the overburden sediments in the Deep Bay area, is primarily recharged by precipitation on upland areas to the south, and also by precipitation falling directly on the unconfined aquifer in the vicinity of Deep Bay. However, the proportion of precipitation on the land surface that eventually becomes part of the groundwater flow regime varies from place to place, depending on topography, geology, vegetation, infiltration conditions and the amount and timing of precipitation throughout the year. Under the usual hydrogeologic conditions in a temperate climate, a portion of the precipitation is lost to runoff as surface water and a major amount is lost to evapotranspiration; the remainder infiltrates soil to reach an aquifer and become groundwater. Experience shows that the fraction of total annual precipitation (TAP) reaching the water table (recharging groundwater) is usually quite small, ranging from about 2 to 10% of TAP. (Reference: Walton, W.C., 1970, Groundwater Resource Evaluation, McGraw Hill, Chapter 6, Groundwater Recharge and Runoff, pp ) Evapotranspiration is the combined amount of precipitation returned to the atmosphere by evaporation and through plant transpiration, which is controlled by seasonal changes and by local weather conditions. Evidence from many hydrographs of observation wells in shallow aquifers in areas with a temperate climate, shows that, due to the evapotranspiration, there is very little or zero recharge, to the groundwater regime during the springsummer growing season in areas covered by vegetation. At the end of the growing season, evapotranspiration rapidly declines and precipitation which moves down from the land surface must replace the soil moisture deficiency, which has developed in the growing season, until soil moisture reaches field capacity, before water from precipitation can move down from the soil to start groundwater recharge. The hydrographs usually show the recharge season to be from December to March or April depending on weather and local conditions. Groundwater recharge ends when vigorous plant growth starts and a high rate of evapotranspiration resumes. Under these conditions, the timing of precipitation is an important factor in groundwater recharge. Higherthanaverage summer precipitation may have little effect on groundwater recharge while sparse winter precipitation can have a large effect. Pacific Hydrology Consultants Ltd.

14 Completion Report Groundwater Study for Deep Bay Waterworks District Page HYDROGEOLOGICAL INVESTIGATION 3.1 General To evaluate the present hydrogeologic conditions at Deep Bay, PHCL have compiled and reviewed the available data, which were obtained either from the DBWD office or from the websites. The data which were taken into consideration include the following: 1. Hydrographs of Provincial Observation Wells No. 310 and 331; 2. Monthly data reports with respect to mean temperature and total precipitation since 1944, from Comox Airport, which is located about 80 km north of Deep Bay; and, 3. Monthly operations/maintenance reports from the DBWD office, which show the number of connections, manual monthly water level readings of Wells No. 310 and 331, total amount of groundwater pumped from each well in every month, etc. The data cover the period January 2004 to October Inspections and pump testing of each production well during the November 2006 reconnaissance by PHCL were also evaluated. Based on the existing data provided to PHCL during the investigation and our knowledge of the groundwater hydrology of the area from our past files, we understand that one of the main concerns raised by DBWD is what will happen to the existing water system under severe drought conditions. Therefore, a large part of this project is the assessment of groundwater sources at Deep Bay, and how they are affected by drought. Based on the available data, the objectives of the desktop study are to: 1. Determine whether the capacities of the DBWD wells will be significantly reduced under severe drought conditions. 2. Evaluate whether the groundwater quality, especially the chemical parameters, of the Deep Bay aquifer complex has changed over the years due to use of the existing production wells as the sole water sources for the Deep Bay water system. Pacific Hydrology Consultants Ltd.

15 Completion Report Groundwater Study for Deep Bay Waterworks District Page Hydrographs of Provincial Observation Wells No. 310 and Discussions The hydrographs of the two provincial observation wells, No. 310 located on the south side of the Island Highway and No. 331 located in the DBWD well field, effectively show the annual fluctuations of the groundwater level in each of the two wells. Provincial Observation Well No. 331, which is also DBWD Well 796, is located in close proximity to Wells 477, 585, 690 and 8 97, on which the existing system depends most of the time. Observation Well No. 310, which was drilled as a test well for DBWD in 1977, is located further south than the existing production wells and Well No As shown on the hydrographs (Figures 3 and 4), which are included on Page 8 for reference, the groundwater levels in the two Observation Wells behave in slightly different manners, in that the annual lows in Well No. 331 usually occur in the late August/early September period and highs in late January, whereas the lows in Well No. 310 occur in the October/November period and highs in late February. The water level data from Well No. 310, which have been collected since the start of its use as an observation well in 1990, shows that the natural seasonal fluctuation in Well No. 310 before the year 2001 was not more than 2.5 m (8.2 ft); however, the amount of fluctuation became less after 2001, with not more than 1.75 m (5.7 ft) of seasonal groundwater fluctuation. The reason for the change in the degree of water level fluctuation is uncertain to us. We also note that the highest water level was observed in 1999, at about 6.25 m (20.5 ft), referenced to the top of the casing, and the lowest in 2001 and 2002 at about 10.5 m (34.4 ft). The lowerthanaverage water levels throughout the years 2000 to 2002 were mainly due to the belowaverage total precipitation, which resulted in a long drought period. Similar lowerthanaverage water levels were observed in Well No. 331 from the period 2000 to 2002, although water level readings were not recorded from February 2000, until mid Therefore, the lowest water level in Well No. 331 was also observed in late 2001 and late The highest water levels were recorded in early 1998 and early 1999, which correspond to the highest level in Well No. 310 in early Since January 1990, when Observation Well No. 310 was established, the hydrograph from Well No. 310 shows that there have been three drought periods late 1980's ending in 1991, 1993 to 1994 and 2000 through about If we measure drought severity by the lowering of the water table (reduced flow through the aquifer), the 1991 and 1993 events were about the same and the drought was the longest and the most severe. Pacific Hydrology Consultants Ltd.

16 Completion Report Groundwater Study for Deep Bay Waterworks District Page Figure 3. Hydrograph of Provincial Observation Well No Water Level (m) Figure 4. Hydrograph of Provincial Date Observation Well No Jan90 Jan91 Jan92 Jan93 Jan94 Jan95 Jan96 Jan97 Jan98 Jan99 Jan00 Jan01 Jan02 Jan03 Jan04 Jan05 Jan06 Jan07 Jan90 Jan91 Jan92 Jan93 Jan94 Jan95 Jan96 Jan97 Jan98 Jan99 Jan00 Jan01 Jan02 Jan03 Jan04 Jan05 Jan06 Jan07 Water Level (m) Date Pacific Hydrology Consultants Ltd.

17 Completion Report Groundwater Study for Deep Bay Waterworks District Page Results In examining the hydrograph from Observation Well No. 310 from January 1990 to 2006, an obvious question is whether the hydrograph shows the effect of local activity, for example, pumping from the well field; we deduce, that it does not, perhaps mostly because of the hydrology of the aquifer at Deep Bay. Well No. 310 is ideally located in an area of minimal disturbance, to show the water level in the shallow aquifer in equilibrium with local environmental conditions. Using monthly precipitation records from Comox Airport obtained from Environment Canada, we find that winter precipitation for several average years is in the range of 1050 to 1400 mm per month. In the brief low level period in 1992 to 1993, the monthly winter precipitation was about 830 mm. In the longer and more severe drought, which starts in 2000, the winter precipitation was 776 mm (2.54 ft) in , 639 mm (2.1 ft) in , and 987 mm (3.2 ft) in The hydrograph from Well No. 310 shows that the annual average low water level was about 1.5 m (5 ft) lower than in the high period of 1996 to The low at the end of 2005 was about one metre lower than in the period. The hydrograph from Provincial Observation Well No. 331 does not show the period of 2000 to 2003, as there is a gap in data from early 2000 to late However, during the data gap, the average level had dropped from about 4.5 m (14.8 ft) below ground to about 5.5 m (18 ft) rising to about 5.0 m (16.4 ft) in 2003 through 2005 and Thus, the drop in the average water level in Well No. 331, which is in the most productive part of the well field, was about 1 m (3.3 ft). However, following the severe drought in the 2000 and 2002 period, the water levels in both Wells No. 310 and 331 have recovered, although not yet to their predrought conditions probably indicating that the water level in the source aquifer has not reached its predrought level. 3.3 Monthly Operation / Maintenance Reports Discussions The monthly record sheets prepared by Mr. Dennison of DBWD, included in Appendix C, are essential in showing the actual production of water from each well and the total running time for each well pump for the month from which average pumping rates have been calculated. On each sheet, the monthly data are followed by a description of water system activities during the month. It is our opinion that the monthly data are essential for an effective program of aquifer and water system management particularly for a growing community, solely dependent on wells. Pacific Hydrology Consultants Ltd.

18 Completion Report Groundwater Study for Deep Bay Waterworks District Page 10 For easy reference, we have tabulated the monthly worksheets prepared by Mr. Dennison for the period January 2004 to December 2006 and present the data on a spreadsheet in Appendix D. On each spreadsheet, the data have been divided into nine (9) columns; the columns represent the following: 1. "Date" and "Days" for each month, the number of days varies with the starting and ending dates on the monthly work sheets. 2. "Hours for the Month" shows the total hours of the days of each pumping month. 3. "Number of Wells in Use" is the number of wells which were used during each month. However, each well may have different pumping hours. For example, during a month when three wells were in use, one pump may have run for several hundred hours while another may have run less than 50 hours. Thus, the total pump hours includes all the pumps in use, pumping at various rates. 4. "Number of Connections" was assumed to be 525 from January 2004 until April 2006 after which the actual number of connections is shown on the monthly work sheets. 5. "Total Water Pumped" is the sum of the amounts for the period, shown by the "totalizing water meter" at each of the wells which were used during the month. 6. "Total Pump Hours" is the total number of pumping hours for the wells which were in use during the month. The hours may vary from well to well, but the total is the sum of hours shown by the "totalizing hour meter" at each pump. 7. "Percentage of Time Pumping" is the percentage of the total hours in the month, if the pumps which were operating during the month had run continuously for the total hours in that month. For example, if three pumps ran a total of 330 hours out of a possible total of 3 x 720 equals 2160 hours, the percentage of running time is 330/2160 equals 15.3% of the potential time for the three wells. 8. "Average Pumping Rate" is the total water pumped during the month divided by total running time for all the pumps which were in use during the month. Again, it varies with the capacities and the running times of the pumps which were used. 9. "Average Daily Use per Connection" is the total volume of water pumped during the month, divided by the total number of connections on the system. It is not a precise quantity, particularly in winter months when an unknown number of families were not at home during part of the winter. Also, total volume pumped includes leakage and nondomestic usage. The actual average use for all the active connections would be slightly higher. Pacific Hydrology Consultants Ltd.

19 Completion Report Groundwater Study for Deep Bay Waterworks District Page 11 The tabulated monthly data have been plotted on several graphs to show how the various parameters have varied during the past three years. The plots are also included in Appendix D. What do these data show? 1. There has been a very large decrease in the amount of water pumped in the maximum month of each year, from 63,700 m 3 (14,009,000 igal) in 2004 to 48,500 m 3 (10,673,600 igal) in 2005, and to 31,200 m 3 (6,856,300 igal) in 2006, following the installation of water meters on the existing system, and perhaps partly by repairs of leaks in the distribution system. 2. Water demand varies, as expected, from a low in winter months to a maximum in summer. The amount of water pumped in the minimum month in 2006 is about 24% of the maximum. In 2004 and 2005, the percentages were 15.5% and 17%, respectively, mainly because summer demand has been reduced. 3. Average daily water use per connection depends on knowing the number of connections. For a long time, it was calculated on the basis of an assumed 525 connections, but starting in 2006 the actual number of connections has been recorded each month, showing that the number of connections has increased to 550 in October However, the increase from 525 has not been large, so the earlier data, which are based on 525, are reasonably correct. These numbers are tabulated below; units are imp. gal/day per connection. Table 2 below shows the daily water use per each household during the maximum months and minimum months for each year since Table 2. Average Daily Use per Connection for the Period 2004 to 2006 in the Deep Bay Waterworks District Water System 2004 (Jan Dec) 2005 (Jan Dec) 2006 (Jan Oct) For maximum month, average day For minimum month, average day Minimum as % of Maximum Pacific Hydrology Consultants Ltd.

20 Completion Report Groundwater Study for Deep Bay Waterworks District Page Results The data for the period January 2004 to October 2006, show a remarkable reduction in the total monthly water pumped from a maximum of about 14 million igal in July of 2004, to about 7 million igal in July of 2006, when the number of connections was larger than it was in The main reasons for this reduction certainly include the installation of water meters and reduction of leakage. In the maximum month, July 2004, six of the seven production wells (all wells except Well 173) were in operation for a total pumping time of 2420 hours, which was about 56% of the total potential pumping time for the six wells, or 48% of the time if all seven wells had been in operation. In that month, the well with the maximum pumping time was Well 897, which was pumped for 489 hours, about 68% of the 720 hours of the month. Thus, at the highest monthly demand since January 2004, the total well capacity was almost twice the demand for the month. This explanation is somewhat oversimplified, because demand varies greatly from day to day and the peak daily demand is probably also supplied in part from the reservoir storage. The most striking feature of the data plots, particularly the monthly total water pumped during the past three years, is the large reduction in water use during summer months, while the use in winter months decreased by only a small amount. This shows clearly that the total inhouse water use remains almost constant, at about 2 million igal/month. Assuming a 30 day month and about 525 connections, the average daily inhouse use per connection would be about 127 igal/day. In the year 2006, the use of water for outdoors activities in midsummer was probably about 286 igal/day, which is more than twice as high as inhouse uses. Both of these estimates include system leakage, water used in flushing lines, fire drills, water for boats, etc., all of which may be about 15% of the water pumped. Therefore, the estimates of water use per connection may be too high by 10% or more. 3.4 Well Capacity Ratings and Performances The performances of the seven operating wells have been evaluated during the field reconnaissance carried out by Ed Livingston and Carol Ma of PHCL, assisted by Mr. Dennison on November 1, The durations of the tests on the operating wells, except Wells 585 and 897, were relatively brief, about 10 minutes. Because Wells 585 and 897, according to Mr. Dennison and as shown on the monthly operation/maintenance reports, are the most productive wells for the Deep Bay water system, Well 585 was pump tested for 214 minutes (about 3.5 hours) and Well 897 for 204 minutes (3.4 hours), in order to better understand the responses of the wells to highrate pumping; the two wells were pumped simultaneously for more than 3 hours. Pacific Hydrology Consultants Ltd.

21 Completion Report Groundwater Study for Deep Bay Waterworks District Page 13 Results of the November 2006 testing have been tabulated in Table 3 below, for comparison to the original ratings and to the average actual pumping rates taken from the monthly data sheets. The original rating of each well was assigned at the time of well completion and the pumping rates calculated from the monthly data sheets and the November 2006 testing are calculated from totals of water pumped shown by the water meters and the total pumping hours from the hour meters. Obviously, the calculated rates depend on the accuracy of the water meters and the hour meters. The performances of all seven operating wells are also tabulated in Tables 3 and 4 on the next page for comparison to their performances during the capacity testing of Well 897 in Table 3. Pumping Rates of Wells in Deep Bay Waterworks District Water System Well Original Rates Rates from Monthly Reports Rates from November 1, 2006 Testing igpm Lps igpm Lps igpm Lps 173 (#13731) (#13732) (#13733) (#13734) (#13735) (#13736) (Obs. Well No. 331) Obs. Well No Table 4. Well (Date) Performances of Wells in Deep Bay Waterworks District System Duration of Pumping Rate Drawdown Specific Capacity Pumping (minutes) igpm Lps ft m igpm/ft Lps /m 173 (10/29/96) (11/01/06) (10/29/96) (11/01/06) (10/29/96) (11/01/06) Pacific Hydrology Consultants Ltd.

22 Completion Report Groundwater Study for Deep Bay Waterworks District Page 14 Well (Date) Duration of Pumping Rate Drawdown Specific Capacity Pumping (minutes) igpm Lps ft m igpm/ft Lps/m 477 (10/29/96) (11/01/06) (10/29/96) (11/01/06) (10/29/96) (11/01/06) (10/30/97) (11/01/06) In general, the actual pumping rates during the year 2006 were more or less the same as the original ratings, except for Well 585 which was rated at 7.42 Lps (98 igpm), but has recently been pumping at Lps (134 igpm). There are several possible explanations for this: 1. the water meter may be reading too high; 2. the well may have undergone additional development with use, resulting in increased well capacity; and/or, 3. the highrate pumping may be using more than the 70% of the total available drawdown on which the rating was based. In any case, it will not damage the well. We note also that the average monthly pumping rate for Well 477 in 2006 was about 5.29 Lps (70 igpm); however, during the testing in November 2006 by PHCL, the rate was calculated to be about 8.63 Lps (114 igpm), which was about 1.5 times higher than the average rate. Because of the great discrepancy, it is our opinion that the test rate during the November 2006 testing may not be correct. There is no obvious evidence showing that the performance of any of the operating wells has decreased significantly since the well completion. The specific capacity is determined by dividing the pumping rate at the end of the testing, which is this case is about 10 minutes in most of the wells; however, because of the short duration of the testing carried out on November 1, 2007, the specific capacity of each well, except Wells 369 and 477, is slightly higher than the Pacific Hydrology Consultants Ltd.

23 Completion Report Groundwater Study for Deep Bay Waterworks District Page 15 specific capacity assigned in the 1996 testing, which is considered reasonable, as the specific capacity usually will decrease with longer pumping. We note that the specific capacities of Well 369 in 1996 and 2006 were the same, about 0.72 Lps/m (2.89 igpm/ft) at 480 minutes of continuous pumping at 5.62 Lps (74.14 igpm) in 1996 and about Lps/m (2.88 igpm/ft) at 10.5 minutes of pumping at a rate of 6.13 Lps (81 igpm) in November Because of the error in the pumping rate, we believe that the specific capacity of Well 477 was also incorrect, and should not be used for evaluation. 3.5 Well Interference at Deep Bay Well Field The possibility of problems with interference between wells caused by pumping was brought up in the Drought Management Plan of 2005 and was an important item in the original Request for a Proposal by DBWD. Our analysis of data collected since January 2004 and data in several previous PHCL reports shows that interference between the operating wells is not significant and is not likely to increase in times of drought. Since the installation of automatic water level recorders in the two Provincial Observation Wells, programmed for readings at onehour intervals, it is possible to closely evaluate the shortterm fluctuations in the water levels in these two Wells. Below are two hydrographs of Observation Well No. 331, during the periods May 31 to September 6, 2004 (Figure 5), and, May 31 to June 30, 2006 (Figure 6). Well No. 331 is located in close proximity to the most productive wells at Deep Bay. As shown on the two hydrographs, the total decline in the water level for the month of July 2004 was about 0.72 m (2.36 ft), which was caused by both the pumping of the DBWD wells and the natural seasonal decline. The decline was about 0.32 m (1.05 ft) in the month of June Unfortunately, the available data for hourly water level measurements in 2006 were only up to June 30. July of 2004 was the month of highest water consumption, and following the installation of water meters, the total water consumption has declined and, as discussed earlier, the monthly water consumption in July 2006 was only about half as much as in July There were two unusual water level declines in the summer of 2004, between June 10 and 23, and, July 12 and 19, which were likely due to longterm pumping of the DBWD Wells, when the water consumption was high; the declines were about 0.30 and m (1.0 and 1.14 ft), respectively. Other than the 0.1 m (0.33 ft) interference drawdown of water level observed on June 7, 2006, there was no obvious interference in June of 2006; the usual interference was about 0.04 m (0.13 ft), certainly a negligible amount. Wells at closer spacing would show more interference, but even a three fold increase to 0.12 m (0.39 ft) is still insignificant. Pacific Hydrology Consultants Ltd.

24 Completion Report Groundwater Study for Deep Bay Waterworks District Page Figure 5. Hydrograph of Observation Well No. 331 During the Period May 31 to September 6, May Jun Jun Jul Jul2004 9Aug Aug2004 6Sep2004 Water Level Below Ground (m) Date 4.90 Figure 6. Hydrograph of Observation Well No. 331 During the Period May 31 to June 30, Water Level Below Ground (m) May2006 2Jun2006 4Jun2006 6Jun2006 8Jun Jun Jun Jun Jun Jun Jun Jun Jun Jun Jun Jun2006 Date Pacific Hydrology Consultants Ltd.

25 Completion Report Groundwater Study for Deep Bay Waterworks District Page TOTAL WELL CAPACITY The question arising from hydrograph data is whether the twoyear drought from 2000 to 2002, had a significant effect on capacities of the Deep Bay wells. As pointed out in Section 2.1, the shallow aquifer at Deep Bay is essentially a conduit conveying groundwater from the recharge area to the discharge area and the sea. In vicinity of the Deep Bay wellfield, the groundwater is not an underground storage reservoir, which is drained by natural discharge and/or by pumping from wells, in this case, from the Deep Bay wells. The static water levels in the production wells are maintained by the groundwater flow through the aquifer, which is similar to the level of water in a stream maintained by flow in the stream. Under the hydrologic conditions at Deep Bay, reducing groundwater consumption has no significant effect on the amount of water which is flowing through the aquifer and eventually flowing into the sea. However, low water level in the aquifer reduces the total available drawdown of the wells, thereby reducing the ability of the wells to intercept water flowing through the aquifer. More simply stated, the capacity of individual wells is reduced, but groundwater continues to flow through the aquifer. When intense drought reduces water levels and well capacities by a large amount, the excess of total well capacity of the Deep Bay system, especially because the wells are spread out across the direction of groundwater flow, makes it possible to maintain the capacity of the system to meet the needs of DBWD. In addition, considering the total available drawdown of the wells and the high total capacity of the wells in the Deep Bay system, the decrease in capacity of the system to supple DBWD should be insignificant. In other words, by pumping all the wells at rates which have been reduced to match the lower water levels, and by pumping for longer periods, the capacity of the system can be maintained. Reducing water consumption below what the wells are able to pump, does not save water because the water not intercepted by the wells continues to flow into the sea. Since there are no groundwater users "downstream" from the DBWD wells, there is no reason to pump less water than the wells can intercept. We note on page 9 41 of the Drought Management Plan (2005), that local drought state triggers are based on observations of the minimum water level in Observation Well No. 310, to alert the DBWD management to take certain measures to reduce water consumption. We do not agree that water consumption should be reduced for that reason. Although we are not certain about the maximum daily rate of water use for the system, the total capacity of the seven DBWD operating wells is much higher than required at the present time. This was demonstrated during the summer of 2006, when the water demand was higher than Pacific Hydrology Consultants Ltd.

26 Completion Report Groundwater Study for Deep Bay Waterworks District Page 18 usual and that only two of the wells, Wells 585 and 897, were in production for most of the summer period, with periodic use of Well 690 as a supplementary water source for the system. Concern has been expressed about the ability of the water system to meet fire flows. The main requirement for fire fighting is having sufficient water on demand to meet fire fighting requirements for the types of buildings to be protected. Another important requirement is that the sizes, lengths, etc. of the distribution system piping be such that the required flow of water can be delivered to each building being protected. The supply requirement at Deep Bay is quite good. The reservoir, which delivers water to the system by gravity, has a capacity of 545 m 3 (120,000 igal) and experience shows that the pumping capacity of the wells is sufficient to keep the water level in the reservoir 80% or more full at all times. We understand that a new main has recently been installed to improve the hydraulics of the east end of the system "Jameison loop", where friction losses in the piping were quite high. With gravity flow from the reservoir, there is fire protection even during a major power failure. In addition to the seven operational wells, the system has another production well, Well 796 with rated capacity comparable to Wells 585 and 897; it is presently used as Provincial Observation Well No If Well No. 331 (Well 796) is required as a production well in future, it can be replaced by an inexpensive 150 mm (6") observation well located near the main well field area. Our inspection in November 2006 shows that all of the operating wells are properly equipped with totalizing water meters and hour meters and that all wells contain measuring tubes, so that water levels in the wells can be measured with an electric water level indicator when the pumps are operating or at rest. As mentioned previously, the records of the total water pumped and hours at each well have been recorded by Mr. Dennison on an appropriate data sheet once each month since 2004 and that the records have been properly kept in the DBWD office. The various data can be plotted on yearly graph paper at least once each year to provide a graphic record of the Deep Bay situation. Comparison of the plots from year to year is valuable in showing long term changes, losses to leakage etc. Analysis of longterm records can also be very effective in indicating aquifer capacity. 5.0 GROUNDWATER QUALITY We have compiled and reviewed available analyses from both the DBWD office and from EMS online service, and have tabulated the results in Table 5 which is contained in Appendix E. The results of the miscellaneous analyses cover four of the seven operating wells (Wells 173, 3 69, 690 and 897) and the two provincial observation wells, from which groundwater samples were collected periodically by Ministry of Environment (MoE) from 1993 to Pacific Hydrology Consultants Ltd.