Proactive disclosure Print version ![Print version Print version](/web/20061103024329im_/http://geoscape.nrcan.gc.ca/esst_images/_printversion2.gif) ![ÿ](/web/20061103024329im_/http://geoscape.nrcan.gc.ca/esst_images/_spacer.gif) | ![ÿ](/web/20061103024329im_/http://geoscape.nrcan.gc.ca/esst_images/_spacer.gif) | ![Geoscape Canada Geoscape Canada](/web/20061103024329im_/http://geoscape.nrcan.gc.ca/esst_images/geoscape_e.jpeg) Natural Resources Canada > Earth Sciences Sector > Priorities > Geoscape Canada > Ottawa-Gatineau
Geoscape Ottawa-Gatineau Groundwater
The groundwater system
Groundwater provides much of the water used for residential and
agricultural purposes in rural parts of the region. It also moves
nutrients to vegetation and provides flow to streams. Groundwater is
stored in, and moves through, porous sand and gravel and porous or
fractured bedrock (aquifers). Aquifers are recharged by the infiltration
of rainwater or snowmelt from the ground surface. However, throughout much
of the Ottawa valley, an impervious blanket (aquitard) of Champlain Sea
silt and clay limits aquifer recharge. Excessive pumping of groundwater
can deplete aquifers.
Water quality
Slow flow rates and long residence times in aquifers cause groundwater
quality to be controlled by the chemical composition of the aquifer.
Pyrite-bearing rocks yield water with a characteristic rotten-egg odour.
Water from salt-rich Champlain Sea sediments can be saline. Calcium and
magnesium, dissolved from limestone and dolostone, produce what is
known as hard water.
Vulnerable!
Groundwater can be contaminated. Contaminant sources in urban areas
include gas stations, dry cleaners, garbage dumps, snow-disposal dumps,
and industrial sites. Municipal waste-disposal sites in Carp, Gloucester,
and Aylmer have leaked and contaminated aquifers. In rural areas,
livestock wastes, pesticides, and fertilizers have polluted
groundwater.
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Did you know? ... In 1991, the improper disposal of
dry-cleaning chemicals in Manotick contaminated about 100 household
wells and required development of a water main for local residents
at a cost of millions of dollars. |
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