... 02' materials.?e largest known yield is 2000 US, gallons per minute produced

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1 , F a J. C. Foweraker J. M. Petrie Geologist Groundwater. Section Groundwater Section September 8 76 \! Columbia River Groundwater Potential B $3 --B!+- Attached is a report prep8.red by Mr, Bill Hodge, Engineering Assistant, entitlqd 'A Prelininary Study of Groundwater Potential in the Lower Columbia River Basin', The,p$ucity of available data does not allow an indepth. evaluation of the groundwater potential but 'rather, serves to give a general account of the geology, aquifers, well yields, water quality and potential problems. The Columbia River below Castlegar is genera:lly deeply entrenched in vafleyfill deposits. and intssiwe and volcanic bedaock, The valley is infilled to approximately the 1500-foot elevation (200 feet above river level) with a complex assortment of Pleistocene and Recent till, gravel, sand and silt, These materials comprise valley bottom and terrace deposits, and may mantle bedrock slopes to as much as the 3000-foot lttvel. %?le buried bedrock topography is nost irregular, resulting in consiclerable varfations in the thickness of the surficial deposits, The few well records on file record the prescmck of some favourable aquifer materials.?e largest known yield is 2000 U*S, gallons per minute produced from a gravel packed well coqleted in a fine sand aquifer at Trail (Brown 1971). On the other hand, some we:lls intersect' bedrock above the water table elevation and thus are dry. The hydrogeology of 'the area reflects the ionplex geology. Often the water table fluctuates in sympathy with the river level which indicates a direct hydraulic connection, In some cases there is a lag period of as nuch as thirty days before the groundwater table responds to changes in the river level. In such a case, there is an indirect connection between the river and the aquifer (Brow 1971). A third situation exists in which the piezometric surface of the deeper aquifers fluctuates in response to the loading of the aquifer by the river, (i.e. high river levels exert increased pressme on the urlderlying aquifer, producing a raised water level in wells penetrating this aquifer), (Brown 1965). These aquifers are probably recharged by underfloy through the fissured bedrock, and perhaps, by leakaga't;%en the river is at high flows...*. 02'

2 F *. 2 ' i.. *2 I! -e 3, C= Powcraker Sapternbar 8, 1976 Of concern in this area fs the qualit4 of the water. The groundwater is generally hard and has a high total dissolvtrd solids content, It is expected that thisp@mr quality is produced by long tho fesidenco in the sediments and not by bedrock derived waters or river transported contaminants. The quality of the Columbia River water has improved with the implementation of pollution regulitions. Tlhus exploitation of aquifers in which direct infiltration of the river nay occur is likely to plloduce good quality water. It mush be pointed cat, that,.at times. of maginm river turbidity, silt may be drawn into the aquifer with %he gossibibity o-e subsequent decrease in.water quality. 'and well performance. The withdrawst1 of large quantftbs of groundwater Erom river-connected aquifors nay possibly fnfluunce,rivsr flows and thus have some deletrious e'ffect on surface water liccncea. This possibility is considered as remote. It is considered {impractical to detail well drilling costs at this fime, but some generalizations can be made, Po? low yiglds (say in the order of 100 UbS. gpn) from shallow sand aqd. gravel aquifers adjacent to the r%ver, then a well point system is considered practical (Ed Livingston, pers corn)., Drilled wells are more expensive, ad a 250-foot well of 12 inches in diameter, capable of'producing 1800 U.S. gpm could.cost as much as $25,000, I. References -L BTOW~ W.L Brown N.L East Trail WellsL. Apxil Froduetion Well-No.,3 for The City- of Trail, November J E4. Betric Geologist * &oundwater Section Attach

3 Seiiteniber 8, 1976 A PREIJMTNRIZY _--- STUDY OF GROUNDWATER Powmm IN THE LOWER COLUbIBIA RIVER BASIN 1. -Iintroduction A preliminary study of groundwater potential in the Lower Columbia River Water Basin reaching from Castlegar to Waneta near the U.S. border has been conducted, to determine if, where, and to what extent real groundwater potential may exist. All domestic and major production wells records have been reviewed and examined separately to distinguish those wells supplied through direct river infiltration from those which may receive partial or total recharge from an alternate source. A map showing specific groundwater yields from springs and wells located in confined, partially confined and non-confined aquifers has been prepared for inclusion in this report. All available groundwater chemistry has been studied in an effort to obtain a clear understanding of water qualities indicative of certain areas and to determine where possible pollutants lie which could affect water quality. Aerial photographs, surficial and bedrock geology maps, Columbia River Basin mapping, drill and pump test reports and general notes on file have been reviewed in depth to supplement well card information. 2. Surficial Geology The formation of the Columbia River occurred during the Pleistocene Epoch. The reach of the Columbia from Castlegar to Waneta is cut into glacial outwash materials, which were deposited after the retreat of the last major ice advance (see attached map). The bed and banks are covered with a veneer of coarse gravels which are the remains of reworked upper gravels, from which the fines have been separated. The nature of the deposited outwash material varies and was not laid down as a series of continuous sequences of sediments, but rather by several periods of deposition and erosion, leaving in areas a complex cut and fill sedimentary sequence. It is most probable that ice from the Kootenay River, terminated at the junction of the Kootenay and Columbia Rivers near Castlegar, forming a large ice dam (Brown, 1971). This theory is further supported by the presence of moraine-like features near this junction. High terraces of similar elevation downstream of Castlegar indicate drainage may have been clammed, near Waneta at the mouth of the Pend-d-Oreille River. 3. Hydrogeology In order to simplify presentation here, the Columbia River reaching from Waneta to Castlegar has been divided into specific areas. A discussion concerning the local geology, hydrogeology and hydrochemistry has been included for each area. Although groundwater potential undoubtedly exists throughout outwash areas adjacent to the river, uniformity of material and aquifer development varies considerably.... 2

4 ;mianeta -- - Columbia Gardens All information reviewed involving this area has been based on aerial photograph interpretation and available surficial and bedrock mapping. Unfortunately, well card data is not available at this time in regions south of Columbia Gardens and therefore thichness and nature of deposits at this location arc: unknown. Extensive deposits of glacial fluvial dutwash have been noted directly across the Columbia River from Waneta, and extend northward for over a mile before terminating around volcanic rock and minor interbedded siltstone. It can be assumed that the outwash material here is representative of deposits found in areas adjacent to and throughout the reach of the Lower Columbia River. Deposition varies widely and in some areas is quite extensive. Wells producing outstanding yields from this material have been sited at Trail and Kinnard. The nearest recorded wells to the Waneta area on file are situated at Columbia Gardens, where existing data has shown these wells to produce relatively moderate to low yields, the principal aquifer being, poorly sorted silty sands and gravels overlying bedrock. Overburden in this area is shallow and depths to bedrock vary from 11' to 38' below ground level. An abundance of spring activity upslope from this area suggests recharge may be supplied from this source. It appears unrealistic to attempt to extract groundwater from bedrock aquifers, as substantial yields may be extracted from outwash materials adjacent to the river. At present the chemical characteristics of well water in this region are unknown and can only be assumed to be of similar quality of that upstream. The quality of the Columbia River water is monitored regularly by the Pollution Control Branch of the Department of Environment. A number of saqpling stations exist, and since 1970, have been sampled on a regular monthly basis. General quality of the Columbia River is discussed briefly, later in this report. 3.2 Montrose - Trail The Groundwater Section has on file, records of 8 drilled wells southeast of Trail near Montrose. These wells are all sited in glacial outwash deposits along the east bank of the Columbia River. The majority of these wells are relatively shallow with bedrock encountered at approximately 70'. All report excellent yields of between 40 and 200 gpm, with the principal aquifer reported as fine silty sand and gravel. Because of proximity to the river and high permeability, the potential for induced infiltration from the river to the aquifer is good. Confining layers of dense, highly compacted silt and clay, are generally absent. These wells may receive additional recharge from high level drainage and from spring activit? noted to the northeast. High yielding test and production wells have been sited at East Trail and at Sunningdale, north of Trail. Bedrock outcrops irregularly on both sides of the river in the general area of Trail and Sunningdale. The production well record at Trail reports the principal aquifer to be fine sand screened from 309'-363'. A thick, very dense, silty sand has been encountered above this aquifer, including highly compacted,, silty, laminated beds which are common in this specific region. The major... 3

5 - 3 - aenetrated aquifer near Sunningdale is rcported to be well sorted sands and gravels ranging in depths of 140' to 180'. A moderately thick moraine-like deposit, averaging 35' in thickness ovcrlics the sand and gravel formations in the Trail - Sunningdalc area, suggesting perhaps a stagnation and consequent meeting of the ice front here, permitting deposition of this moraine-like material at this point. It is important to note that deterioration and contamination of two production wells at Sunningdale occurred, necessitating their shutdown in Decembcr 1965 after some seven months of continuous operation. It was concluded that the surface water contaminant was the Columbia River (Brown, 1966). This conclusion was fortified by reports of foaming on the Warfield and Tadamac Treatment Plants that obtain their water supply directly from the Columbia River. The probable cause of well deterioration has been determined as a buildup around the well screens of iron produced by the interaction of two types of water. These problems were rectified by the introduction of "Dry Acid Special", reduced pumping, and a number of precautionary steps taken, with recommendations beir.g made should similar conditions reoccur in the future. The quality of well water in the general Trail - Sunningdale area is reported (Brown, 1971) as basically a hard, moderately mineralized water with the dissolved mineralization present primarily as calcium, bicarbonate and sulphate. 3.3 Oasis - Kinnard The Groundwater Section has few well records on file along this stretch of the Columbia River. Except in populated areas such as Kinnard and Castlegar where a concentration of wells are seen, the remaining few are scattered widely. Records of seven drilled wells near Oasis are available, with four of these to the southwest, all relatively shallow, bottomed in bedrock, with the average depth of bedrock reported as 30'. They are generally low yield wells with the aquifer being reported as thin, fine sand layers, poorly sorted with clay interbeds. Wells situated closer to the Columbia River at Oasis report some moderate yields, however, heavy silting appears to be a problem in this specific region where thick formations of silt or silty sand occur. Wells situated to the north near Birchbank and China Creek have reported excellent estimated yields of' between 100 and 300 gpm. The principal aquifer here beding reported as thick formations of fine sand with no silt content. One well in particular, near Blueberry Creek reports bedrock encountered at a depth of 30'. The specific yield of this well is unknown at this time. Field analysis conducted on well water has shown the water to be moderately hard, indicative of water quality throughout the area. Production wells sited at Kinnard and located 400' from the river shoreline, report excellent yields from relatively deep aquifers of clean, well sorted, sands and gravels. From W. L. Brown':; report of 1965 concerning installation of these production wells, it has been noted that the aquifers underlying Trail and Kinnard are confined and not connected to the river. River stage fluctuations c,ause piezometric fluctuations in the aquifers.... 4

6 L'..r -.., 0 i) ale Kinnard area generally appears to consist of clean, well sorted, thick formations of sands and gravels with numerous high yield wells reported. From existing information the area appears to be relatively silt free in comparison to areas further south. Shallow, high yield wells prevail near the junction of the Kootenay and Columbia Rivers near Castlegar with one particular well reporting an excellent yield of 800 gpm from a screened depth of between 34' and 52'; the principal aquifer being clean sands and gravels overlying hardpan (clay?). A thick formation of silty, impervious clay has been noted near the rivers edge at Castlegar. The relatively high iron content reported from Kinnard well*#2 indicates it may be sensitive to pump surges and without proper treatment, could result i.n the deterioration of this well. Generally, well water in the Kinnard area is moderately hard, and highly mineralized, while Castlegar, in one particular example, reported a very hard water with considerable dissolved mineralization and low iron content. 4. Columbia River water quality The major contributing pollution sources to the Columbia River appear to be Sewage Treatment Plants at Castlegar and Trail, Pulp Mill at Castlegar, and the Cominco Plant at Trail. Due to the enormous size and relatively rapid flow of the Columbia River, these pollutants are hardly detectable. There is, however, concern regarding the coliform bacteria count from sewage plant discharge and the fluctuating range of zinc and lead levels discharged from the Cominco Plant in Trail. Although the majority of tannin lignun (residue substance in pulp production) is burned off, some is discharged into the river making taste disagreeable. As previously mentioned, the Pollution Control Branch is regularly monitoring the quality of the Columbia River water at a number of stations along this stretch of the river. 5. Monitoring of river level fluctuation along the Columbia River A number of river level monitoring stations are located between Castlegar and the U.S. border. River levels are monitored either manually (gauge) taken on a weekly or a monthly basis, or by automatic recorders monitoring daily levels on a continuous basis. Readings are recorded in inches or decimal of a metre and then converted, normally assuming a constant river velocity, to cubic feet per second. The method of installation and length of records available for each station varies. Copies of records are available upon request.... 5

7 6. t onclusions and Recommendations (1) The majority of groundwater information available is limited to areas adjacent to the Columbia River. (2) Although limited quantities of groundwater may be extracted from bedrock aquifers it would appear more realistic to attempt extraction whenever possible from areas of outwash deposits. (3) Areas of outwash deposits receiving adequate recharge from the Columbia River should supply satisfactory yields from relatively shallow depths providing no adverse boundary conditions exist in the immediate vicinity of the well. (4) A preliminary test drilling and pump testing program should be initiated prior to any production well construction. (5) For quality reasons, and to gain the added effect of filtration, it may be advantageous to site any wells as far inland as is practical, once an area of permeable and unconfined deposition can be located. (6) Deterioration and contamination of' production wells near Trail has shown extreme care must be taken regarding choice of well location in relation to sites of industrial discharge. (7) The probability of an aquifer in outwash deposits being hydraulically connected to the Columbia River is good, and therefore, care must be taken in determination of pump set:tings to assure a sufficient head of water above suction is available at all times in relation to river levels. (8) Upon completion of a well, quality and quantity should be monitored on a regular schedule. (9) Further exploration is required and should be concentrated in regions of outwash deposition along the Columbia River's major tributaries. 7. References Brown, W.L East Trail Wells - report to C.B.A. Engineering Ltd., Vancouver, B.C. April Brown, W.L. and R.A. Dakin Comp:Letion report on Production Well No. 3 for the City of Trail, November :..6

8 - 6 - a ttle, H.W Geology map - Trail (Rossland-Trail East Half). Geological Survey of Canada, Department of Mines and Technical Surveys, Map Weir, W Report on Deterioration and Contamination of Wells at East Trail, C.B.A. Engineering Ltd., Vancouver, B.C., February J%.r&+e W. S. Hodge Engineering Assistant Groundwater Section Hydrology Division IVater Investigations Branch

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