Abstracts

extract an estimated 27 Mm 3 of water annually. During the spring and summer periods,
flows within Cowichan River are moderated by releases from a weir at Cowichan Lake, to
ensure minimum instream flows are maintained and to provide for a major surface water
extraction (50 to 60 Mm 3 /year) in the lower watershed. A three year, multi-disciplinary
study was conducted to evaluate the interaction between groundwater withdrawals and
surface water flows in Cowichan River. River stage above, within and below the primary
well field reach was monitored on a continuous basis, using in-stream data loggers, coincident
with groundwater level monitoring within a network of off-channel piezometers
and observation wells. The median stream-bed conductivity estimated from in-stream
mini-piezometers and seepage meters was in the range of 2x10 -4 m/s, and losing conditions
were observed consistently within the well field reach. During the summer season,
river flow within the well field reach was measurably reduced as a result of cumulative
groundwater extractions and may impact sensitive aquatic habitat. Stable water isotopes
and geochemistry were utilized to evaluate the relative contribution of groundwater and
surface water inputs to production well withdrawals, and to characterize the quality of
water sources throughout the basin. The complex interactions between consumptive and
non-consumptive water use, competing water demands, and changing precipitation inputs
and snowpacks resulting from climate variability present a challenge for long-term management
and sustainability of an integrated water resource for this region.
Sustainability of Groundwater Resources 1
Thursday October 29, 10:10 – 11:50
Chair: Garth van der Kamp
Room: Wagner
163 - Using numerical groundwater models as a land use planning
tool – Town of Torbay, NL
John Kozuskanich
Stantec Consulting Ltd, Dartmouth, Nova Scotia, Canada
Jonathan Keizer
Stantec Consulting Ltd, Fredericton, New Brunswick, Canada
Carolyn Anstey-Moore & Robert MacLeod
Stantec Consulting Ltd, St. John’s, Newfoundland and Labrador, Canada
The Town of Torbay, NL has grown quickly over the last two decades as a bedroom community
for the neighbouring cities of St. John’s and Mount Pearl. Growth has been primarily
focused in three developments around the periphery of the town in the form of halfto
one-acre lots with private servicing. Approximately 30% of the residents in the older
portions of Torbay rely on municipal servicing for their drinking water which is sourced
from one of the many surface water ponds that dominate the landscape. This study is the
first of its kind in NL to go beyond the scale of individual unserviced developments and
evaluate the cumulative effects of development on the community’s groundwater resources.
IAH-CNC 2015 WATERLOO CONFERENCE
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