Cherry Point Aqui fer (197)
The Cherry Point aquifer has been described by the MOE as comprising about 39 km
2
,
located on the south side of Cowichan Bay, extending north to Mill Bay, and to Shawnigan
Creek in the southwest. Its western (possibly upgradient) boundary is the base of Cobble Hill
and the Dougan Lake Aquifer, while to the east (downgradient) is Arbutus Ridge. This poorly
sorted sand, gravel and silt aquifer (Vashon Drift origin) is described as having moderate
productivity with a reported yield range of 0.01 to 17.35 L/s. A groundwater flow direction has
not been determined but is inferred north towards Cowichan Bay. MOE information originally
indicated that the Cherry Point aquifer has low vulnerability to surface contamination due to
overlying Marine and Glaciomarine deposits, including clay, till and silty sand and gravel.
However, this inferred degree of protection may only apply to the lower confined aquifer (see
below).
Information from a groundwater characterization study completed by Thurber has lead the
MOE to believe that the aquifer is more complex than previously thought, with the deep
confined aquifer intersected by the Arbutus Ridge Utility operating well field corresponding to
MOE Aquifer 197. Within the Strata Plan 1601 well field area there are two distinct water
bearing zones (aquifers) separated by 10 to 25 m of marine clay and silt (aquitard), providing
a natural protective barrier to the water bearing materials in the lower aquifer. Two of three
adjacent golf course irrigation wells supplying the Arbutus Ridge Golf Course are completed
in an upper (unconfined) aquifer zone. The third well is completed in both the upper
(
unconfined) aquifer and lower (confined) aquifer. The adjacent Granfield farm agricultural
irrigation wells tap into the same lower confined aquifer as the Utility wells. Some of the
domestic and irrigation wells in the surrounding area appear to penetrate only the upper
unconfined aquifer, some only the lower confined aquifer while others may intersect both
aquifers. The aquitard separating the shallow and deeper aquifers appears to be missing in
the area near some of the Braithwaite Utility and the Cobble Hill Improvement District wells
(
near the Trans Canada Highway and Fisher Road / Hutchinson Road, about 3 km from
Arbutus Ridge). These wells are at least 60 m deep with continuous permeable granular
materials from the surface. Water levels are typically 30 to 45 m below surface. As such, the
confining layer (aquitard) described above may be discontinuous. .
Groundwater from the Cherry Point aquifer is used for irrigation, commercial, municipal
domestic purposes. Several water licenses also exist on many surface water sources in the
area. Several residents obtain domestic water supply from the Cobble Hill, and Cowichan
Station bedrock aquifers which occur beneath the Cherry Point Aquifer.
Kingburne Aquifer (201)
This is a small confined sand and gravel (Vashon Drift) aquifer of approximately 1.7 km
2
in
size, overlain by thick till, clay and hardpan layers and upland swamp deposits, located west
of Cobble Hill. The inferred aquifer productivity is moderately high with an estimated yield
range of 0.38 to 4.73 L/s. Aquifer vulnerability is low, while groundwater flow direction has not
been determined directly but is inferred west towards the Koksilah River, and recharge is
hypothesized to derive from precipitation and runoff from the surrounding mountains. Water
use is predominantly domestic. Two surface water licenses also exist on Heather Bank Brook.
