Abstracts

channel is buried by about 100 meters of Pleistocene deposits, consisting of mainly of
glacial drift. The channel is thought to be about 1.6 km wide typically.
The hydrogeology of the Pierson Buried Valley Aquifer is not well understood. The aquifer
was first explored in the mid 1960’s by the GSC, and the MCWS. Recently, the GSC
has undertaken additional geophysical work in the area to further define the location of
the channel.
Test drilling that was conducted for a water supply in the area encountered approximately
15 meters of well-rounded fine gravel and coarse sand. A long term pumping test was
conducted, with several weeks of recovery monitoring following the cessation of pumping.
Although the sand and gravel aquifer was highly transmissive, negative boundary conditions
consistent with narrow valley, strip type aquifers were present early during the testing.
The groundwater quality was noted to be slightly brackish, with chlorides approaching 500
mg/L. Samples collected for 18 O and deuterium showed isotopically depleted groundwater
approaching δ 18 O of -20.00 per mille, plotting on the meteoric water line for the area.
These results indicate that the aquifer was recharged during a period of time where climatic
conditions were much colder than present.
Long term monitoring results conducted on the aquifer show that the geochemical changes
and the response to pumping is interesting and insightful to the future development of
the aquifer.
This project is particularly interesting from a geology and hydrogeology point of view, as
it is the first known large scale test of the Pierson Buried Valley Aquifer at high pumping
rates. It is also the first known analysis of the isotope hydrogeology of the aquifer. The
long term monitoring of the aquifer will also aide future research into the Pierson Buried
Valley Aquifer.
161 - Determining the validity of satellite-based measurements of
groundwater level changes in Southern Ontario
Ellen Hachborn & Jana Levison
School of Engineering - University of Guelph, Guelph, Ontario, Canada
Aaron Berg
Department of Geography - University of Guelph, Guelph, Ontario, Canada
Groundwater is an important freshwater resource for the population of Southern Ontario
with over 3 million users in the Great Lakes Basin. Low water conditions are a major concern
for industry, agriculture, and domestic use as many depend on groundwater for their
livelihoods. Historically, low water conditions were relatively rare in Ontario, but as the
demand for water increases and climate patterns shift, low water levels may become more
common. Currently, drought conditions are assessed by conservation authorities and the
Ministry of Natural Resources through surface water measurements according to the Ontario
Low Water Response Plan (OLWRP). No techniques using satellite data have been
applied to measure groundwater level changes at a regional scale in Ontario. The Gravity
Recovery and Climate Experiment (GRACE) satellite mission measures variations in
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