Groundwater Develdpment Program
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r 1 HEAD OF 'IHE LAKE COWUNITY GROUNDWATER DEVELDPMENT PROGRAM L Prepared for The Okanagan Indian Band BY KALA GROUNDWATER CONSULTING LTD. March, 1988 . TABLE OF cXNIlNE Page TABLE OF CONTENTS .................... (i) LIST OF' FIGURES ..................... (ii) SECTION 1 INTRODUCTION ................ 1 SECTION 2 BACKGROUND ................. 2 2.1 General Hydrogeology ............ 2 2.2 Existing Wells in the Vicinity ....... 3 SECTION 3 DESCRIPTION OF PRESENT PROGRAM ....... 4 SECTION 4 RESULTS OF PROGRAM ............. 6 4.1 Well Completion ............... 6 4.2 Aquifer Testing ...............7 SECTION 5 CONCLUSIONS AND RECOMMENDATIONS .......8 APPENDIX LIST OF E'IGURES following page FIGURE 1 VALLEY FILL DEPOSITS ............ 3 FIGURE 2 SEISMIC CROSS-SECTION ........... 3 FIGURE 3 LOCATION OF SEISMIC PROFILE ........ 3 FIGURE 4 MAJOR AQUIFERS SPALLUMCHEEN VALLEY ..... 3 FIGURE 5 WELL COMPLETION DIAGRAM .......... 6 (ii) The present program was carried out at the request of the Okanagan Indian Band to develop a supplementary source of water supply for their comunity at Head of the Lake. Up until the present time, the comunity has utilized a spring as their main source of water supply. Even though this source has met the basic water requirements, it does not supply a sufficient quantity of water to allow future expansion of the comunity, and also there has been some minor problems with water quality in the past. During the present program, exploratory test drilling was conducted by drilling and driving eight-inch casing until a suitable aquifer was encountered. The testhole was then completed as a production well by installing the appropriate screens. Following development of the well, a constant rate aquifer test was carried out. The well completion program did not proceed without its share of problems, in that the casing broke at a weld during the first attempt, and in drilling the second test well, the borehole was overexcavated and as a result the screen assembly collapsed. A successful well was completed on the third attempt. It became very clear to all concerned, that drilling and setting screens in severe heaving sand conditions, by conventional air rotary methods, can lead to problems without the use of water to maintain a hydraulic head on the formation. The following report outlines the nature of the drilling and testing program, provides a discussion of the results and includes recommendations for the safe, long-term pumping rate and pump setting. Detailed information, including the driller's litholog and pump test data is attached to the Appendix. Background information regarding existing hydrogeological conditions is provided in Section 2 of this report . -1- 2.1 General Hydrogeology The site selected for the new well is approximately half way between the rodeo grounds and the church, and is situated on the north side of the main road which traverses the comunity. Topographically, the site is situated on a bench, which drops off with respect to elevation into a broad depressional area on the west side, and extends eastward towards Deep Creek. Based on a report prepared by the Consultative Board for the Okanagan Basin Agreement, this area is underlain by a thick sequence (up to 1500 feet) of surficial sediments. Figure 1 was obtained from this report and is a schematic profile illustrating the nature of the clayey fill deposits occurring between Shuswap River at Enderby and the nortn end of Okanagan Lake. The unconsolidated surficial deposits consist of clay, silt, gravel, sand and mixtures of these, overlying the bedrock surface. Results of a seismic survey which was carried out near the development area in 1966 by the Geological Survey of Canada (see Figure 2), indicate that the valley fill deposits consist of three units as follows: 1) Recent - silt, sand and gravel 2) Fraser Glaciation - Glaciolacustrine silt and clay with minor sand 3) Olympia Interglaciation - fine grained sand with interbedded silt and minor coarser sand and clay containing plant remains. Near the north end of Okanagan Lake, the main aquifers occurring within these deposits consist of fine to medium grained sand in the upper part of the sequence. -2- As indicated in Figure 1, the principle direction of groundwater flow near the north end of Okanagan Lake is from north to south. It should be noted however, that the development area is situated immediately south of the area where the O'Keefe Valley, a major aquifer (see Figure 4) joins the Armstrong Valley. this may have an influencing factor on the groundwater flow direction. 2.2 Existinrr Wells in the Vicinitv The available well log data obtained form tile Water Investigations Branch of the Ministry of Environment, indicate that the majority of existing water wells in the vicinity are completed to depth ranging from 50 to 250 feet. Most of these wells are completed in sand deposits and have reported capacities ranging from 2 to 150 Imperial gallons per minute (Igpm) . Of particular interest with respect to the present progam are the existing wells drilled for Lakehead Estates, and the well drilled for the Okanagan Indian Band at the housing development situated on the west side of the valley. At Lakehead Estates, the main production well is 132 feet in depth and produces a safe yield of 160 Igpm. The well drilled for the Okanagan Indian Band is completed to a depth of 188 feet and has a reported yield of 90 Igpm. Both wells are completed in fine sand deposits, with screens ranging from 10 to 25 thousandths of an inch slot opennings. -3- w Y a -I z a L3 a a2 Y 0 L 0 -z0 I I- 8 z -0 C 0 >- a 0 w n z W 5i W -> 0- 9 v) 3 I m wz W 3 c W a >- W J -J 9 c 0 W i LL 0 cz Q 0 5 I 2 V v) 1 SCHEMATIC OF HYDROGEOLOGICAL SECTIOPS SHOWING SURFlClAL DEPOSITS and GRCUND - WATER FLOW in the NORTH EP!D of the OKANAGAN VALLEY, Figure 1. Valley Fill Deposits. 13-3 2000 - SL - 2a SL Figure 2. Stratigraphic interpreratioc if the ;.alley fill present at seismic profiles I3 a:.? 16. ;Figs. 2i, 2b resprcti\*ely). 2b Keference: Geological Survey of Canada Paper 72 - 8 .. 6 t: ' 51 SPALLUMCHE E N 50‘2s’ ---I-EGEii!D PARI(INS0N LAKE UEOFiOCK Ct!ANNEC AOUIFER --- - INDIAN RESERVE BDY pd O’KLEFC VALLEY AOUlfER .......... DISTRICT I.!UI.IICIPAL D3U:;UARY UPPER PAR1 OF SURFICIAL DEPOSITS --FAN DEPOSITS L?J --- --- CROSS-SEiTl3N B wwiLL: VIEWS. [E] UPPER PAR1 OF SUIIFICIAL DEPOSll S -VALLEY CENTRE Lfl L.OWER PAR” OF SURFICIAL DEPOSITS --- AHEA BOUNDARIES, AFPROXIMATE GEOLOGY IN SPALLUMCHEEN VALLEY I\!@ R‘1’ H 01: A N A G A N 1.. P, I<E Figure 4 3 DESCRIPI'Im OF PRESENT PROGRAM Following the selection of a production well site, the drilling program was initiated on December 17, 1987. All of the drilling operations under the present program were carried out by A & H Construction Ltd. of Abbotsford, B.C., using an air rotary drill equipped with a casing hammer. During the drilling, eight-inch diameter casing was driven into place and the nature of the subsurface materials determined by examination of cuttings returned to surface by air. Preliminary estimates of water production of individual aquifers was determined in a similar fashion, by measuring quantities of water lifted to surface by the rig's air compresser. As previously noted in the Introduction, the program did not proceed without problems. A brief account of the major problems is as follows : 1) At the first location, after drilling to 286 feet, the casing seperated at a weld and the hole was abandoned. This was partially the result of leaving the casing at 247 feet, in heaving sand over the Christmas break, and then requiring extensive use of the hammer to advance the casing. Before moving to Site No. 2, 100 feet of casing was recovered from the testhole. 2)) After drilling through the main aquifer on the second testhole, two attempts were made to jet the screen assembly through approximately 100 feet of sand which had heaved up into the casing. Finally, by bailing out the sand and maintaining a head of water inside the casing, the screen assembly was successfully set into place. However, at this stage the borehole was over-excavated and the screen section collapsed, eventually falling out of the bottom of the casing. All of the casing was retrieved from the second testhole. A successful well was finally completed on the third attempt. In this case, the testhole was drilled to 300 feet, the sand plug was bailed out, and the screen assembly set into place. After pulling back the casing to expose the screens, the well was developed for approximately -4- 40 hours by jetting and lifting water with compressed air. Details of the well completion are discussed in Section 4. In order to assess the long-term capacity of the new well, a constant rate pumping test was conducted. During the test, the well was pumped at a continuous rate of 380 USgpm (312 Igpm) for a 20 hour period. Water level drawdown was measured in the well with an electric well sounder and the discharge rate was monitored by the orifice tube method . Near the end of the test, water samples were collected for a chemical and hydrogen-sulf ide analysis. These samples have been forwarded to Eco-tech Laboratories Ltd. of Kamloops for analyses and the results sent to Civic Engineering Services Ltd. -5- 4 RE3lLl'S OF PROGRAM 4.1 Well Completion During the drilling of the new well, a suitable aquifer was not encountered until the 255-foot depth interval, and continued through to 300 feet.