|Abstract/Description or Keywords
||Groundwater in the Cowichan Valley provides water for domestic purposes, including municipal water supplies, industrial, commercial and agricultural purposes and critical baseflow to streams during dry periods. The Lower Cowichan River layered aquifer system is composed of three sand and gravel aquifers known as the Lower Cowichan River aquifers 186, 187 and 188, referring to the upper, middle and lower aquifers respectively. The two uppermost aquifers have been identified as being highly to moderately vulnerable to potential contamination from surface activities and land-use overlying the aquifer. The main source of groundwater recharge is likely infiltration of precipitation at the land surface; in addition, the aquifer complex, in particular the upper and middle aquifers, are considered hydraulically connected to the Cowichan River. In 2002, the B.C. Ministry of Environment initiated this study of the groundwater quality within the Lower Cowichan River aquifer complex, focussing on wells constructed in the uppermost aquifer layers (aquifers 186 and 187). The objectives of this study were to establish a baseline of ambient groundwater chemistry which could be used to evaluate future changes, and to assess seasonal variability and temporal trends in groundwater quality.