St. Monique/St. Eustache

Hydrogeological Context

Message Warning
This dataset is not reviewed: more information will be made available following the review

Version Metadata
1448b4e3-c71c-43e4-97d8-a4d2d6d99037
Project
Mirabel (AFSOQ)

Datasets

Download

St. Monique/St. Eustache unit description

Update:2014-01-24
The topography of Sainte-Monique/Saint-Eustache sector is characterized by a hill, fluvial terraces and morainic deposits. The sector includes four types of aquifers: bedrock aquifer, outwash cones aquifer, perched fluvial/marine aquifer, superficial aquifer. The bedrock aquifer extends on the entire sector. It is covered by a thin discontinuous till layer. The subglacial meltwater caused till erosion that formed the outwash cones aquifer. As the bedrock aquifer, the outwash cones aquifer is under confined conditions, thus its vulnerability to contamination is low. The aquifer can be connected to the underlying bedrock aquifer by till free windows. A discontinuous marine clay unit overlies the till deposit. The clays are absent on an important part of the sector. The clay unit is covered by marine/fluvial sediments. Perched aquifers are formed where sedimentary deposits overlie the clay unit. Where the sedimentary deposits overlie a clay discontinuity, they form a superficial aquifer. They are directly in contact with the bedrock aquifer. The superficial aquifers are widespread in the sector. Those aquifers are under unconfined conditions, representative of local and regional recharge areas. In these aquifers, water percolates in the soil and flows through the rock fractures of the bedrock aquifer. Water has high iron and manganese concentrations. The total hardness is also high.
Physiography
Hydrogeological regionSt. Lawrence Platform
Hydrogeological context
ReliefIn Sainte-Monique/Saint-Eustache sector, the altitude starts at 0-13 m at Mille Iles River and rise up to 83-96 m atop the hill, located north. The sector is characterized by fluvial terraces and moraine deposits, increasing the altitude from south to north. It also includes areas of gully erosion, decreasing the altitude of ten meters.
Area225.00 km2
Lithology
DescriptionIn ascending order, the geological units are sandstone (Covey Hill and Cairnside formations) and dolostone and limestone (Theresa, Beauharnois and Carillon formations). Carillon formation is just found in the north-east and south-east sector. Dolomite and limestone formations are absent of the western sector. A thin discontinuous layer of till overlies on the bedrock. Over this layer there is a layer of clay. On top of the clay layer, there are different sediment deposits such as littoral and fluvial sediments. Those deposits are sporadic.
Source
Aquifer
AquifersList of aquifers bedrock aquifer perched/superficial aquifer outwash cones aquifer

Unit properties

Surficial aquifer media
Typical value:porous
Description The fluvial and coastal sediments form small discontinuous aquifers, which are perched. Clay unit is absent on an important area of the sector, forming superficial aquifer connected to the bedrock aquifer.
Source Canadian Inventory of Groundwater Resources: Integrated regional hydrogeological characterization of the fractured aquifer system of southwestern Quebec
Bedrock aquifer media
Typical value:fractured
Description Regionally, the bedrock aquifer has 2 hydrogeological units. From the top to the base: 1- Highly fractured Paleozoic rocks and Quaternary glaciofluvial sediments (the sediments overlie the bedrock) 2- fractured Paleozoic rocks The first unit is not widespread on the sector.
Source Canadian Inventory of Groundwater Resources: Integrated regional hydrogeological characterization of the fractured aquifer system of southwestern Quebec
Confinement
Typical value:confined - semi confined - unconfined
Description The sector is covered with a thin discontinuous till layer, creating unconfined and semi confined conditions on an important part of the sector. At some local places, the marine clays are present and confined the watertable.
Source Canadian Inventory of Groundwater Resources: Integrated regional hydrogeological characterization of the fractured aquifer system of southwestern Quebec
Surficial sediment thickness
8.66 m Range: [60 to 50] m
Description The superficial deposits include till, marine, coastal and alluvial sediments.
Source Canadian Inventory of Groundwater Resources: Integrated regional hydrogeological characterization of the fractured aquifer system of southwestern Quebec
Hydrogeological unit thickness
Description Regionally, a thickness of 100 m, including glaciofuvial sediments included in the highly fractured rock unit is considered for bedrock aquifer. This portion of the aquifer accounts for most of the flow, however water is present at greater depths. Considering the absence of limestone formations, the thickness is less than 100 m for Sainte-Monique/Saint-Eustache sector.
Source Canadian Inventory of Groundwater Resources: Integrated regional hydrogeological characterization of the fractured aquifer system of southwestern Quebec
Well depth
19.65 m Range: [0.3 to 176.8] m
Groundwater depth
4.63 m Range: [-0.01 to 47] m
Bedrock hydraulic conductivity
Description For each hydrogeological unit for the regional bedrock aquifer: 1- Highly fractured Paleozoic rock and Quaternary glaciofluvial sediments: K = 7.81E-4 m/s 2- Fractured Paleozoic rock: Kmin 2.7E-11 m/s; Kmax 7.9E-3 m/s; Kmean 2.7E-5 m/s Hydraulic conductivity decreases with the depth. For the Sainte-Monique/Saint-Eustache sector, the conductivities of the second unit is more representative, considering the rock formations present.
Source Canadian Inventory of Groundwater Resources: Integrated regional hydrogeological characterization of the fractured aquifer system of southwestern Quebec
Regional recharge
64 mm/y Range: [0 to 227] mm/y
Aquifer vulnerability
115.95 Range: [64.5 to 160]
Groundwater Quality
Typical value:fresh - hard
Description The dominant water type is Ca-Mg-HCO3 typical of unconfined conditions. Elevated iron and mangenese concentrations have been observed. The total hardness is also elevated.
Source Canadian Inventory of Groundwater Resources: Integrated regional hydrogeological characterization of the fractured aquifer system of southwestern Quebec
Methode Water sampling and analysis