| Brookswood Aquifer |
| The bedrock is covered by marine sediments underlying discontinuous till unit, followed by fine sediments formations. These are covered by the Brookswood aquifer which is composed of glaciofluvial sand and gravel. The aquifer is exposed and consequently is mainly under unconfined conditions. It presents the highest vulnerability to contamination. The aquifer is recharged primarily by direct precipitation (about 55%) and infiltration from streams (about 19%; seasonally dependent). Total recharge is approximately 13Mm3/year. The Campbell and Nicomekl Rivers recharge the aquifer during the wet winter months, but rely mostly on the local watertable for water supply to it during the summer. The average hydraulic conductivity for the Brookswood wells is good, showing good aquifer potential. The aquifer is the second most utilised unconfined aquifers in the Fraser Lowlands. The main uses of groundwater are: commercial, domestic and irrigation. Brookswood groundwater contains elevated concentrations of nitrate, derived primarily from agricultural use of manures. |
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| Abbotsford-Sumas Aquifer |
| The bedrock is covered by marine sediments underlying discontinuous till unit, followed by fine sediments formations. These are covered by the Abbotsford-Sumas aquifer which is composed of glaciofluvial sand and gravel. The glaciofluvial sediments thickness is not well known, but is at least 70 m. The aquifer is exposed and consequently is under unconfined conditions and has moderate to high vulnerability to surface contamination. Groundwater recharges in the glaciofluvial sediments. The total aquifer recharge is about 26.8M m3/yr. In the aquifer, groundwater flows in all directions with significant discharge to the west and east. Prior to development of high yield wells in this aquifer, the total spring discharge was estimated at 8.3M m3/yr. The aquifer is the most utilised unconfined aquifers in the Fraser Lowlands. The main uses of groundwater are: industrial, municipal, irrigation and domestic. In general, records of ground water quality analyses reviewed for the Fraser Basin show the ground water is usually high in dissolved mineralization and also hard. |
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| Fraser Aquifer System |
| The regional aquifer system is composed of two main types of aquifers: fractured bedrock and granular aquifers. In ascending order, the stratigraphy of the area shows a glaciofluvial sand and gravel unit which is exposed and overlies fine sediments (clay and silt) of Fort Langley and Capilano Formations which overlie till discontinuous unit. Marine sediments, overlying the bedrock are found under the till unit. The bedrock of Fraser Lowland and Fraser River delta consists of three, fundamentally different tectono-stratigraphic units: 1) plutonic rocks and subordinate metasedimentary and metavolcanic rocks; 2) formations of sandstone, conglomerate and mudstone and 3) contact between the Paleogene-Neogene succession and Quaternary deposits. The glaciofluvial sediments comprise the granular aquifers. There are many aquifers in the glaciofluvial sediments; mapping has identified more than 200 aquifers in the region. Informations on granular aquifers are from Brookswood and Abbotsford-Sumas aquifers. Granular aquifers are separated from the roc aquifer by aquitard units, which limited the interaction between the aquifers. Water percolates through the glaciofluvial sediments or fractures of coastal mountains. In the granular aquifer, it flows through the voids. In the rock aquifer, the intergranular porosity is very low thus water flows through complex fracture systems. It mostly discharges by submarine seepage. Considering that it is covered by multiple sediments units, the bedrock aquifer has low vulnerability. However, the granular aquifers are very vulnerable to contaminations. Those aquifers are characterized by good aquifer potential and are exploited for commercial, municipal and domestic uses and for irrigation. The rock aquifer has low aquifer potential. It is less exploited than the granular aquifers, but it represents the source of ground water for areas north of the Fraser River sediments. In general, records of ground water quality analyses reviewed for the Fraser Basin show the groundwater is usually high in dissolved mineralization and also hard. |
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Groundwater Information Network