Waterloo Moraine aquifer system

Aquifer System

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Waterloo Moraine aquifer system unit description

Update:2014-03-13
The Waterloo Moraine is a sand and gravel deposit with facies transitions to mud. It is up to 140 m thick with an average thickness of 54 m (Bajc et al 2014). It forms the most prolific aquifer complex within the surficial geological succession that from bedrock, consists of units, including i) ) Pre-Canning glaciofluvial deposits; ii) Canning sediment; iii) Pre-Catfish glaciofluvial deposits; iv) Catfish Creek Till; v) Waterloo Moraine deposits; and vi) Upper tills (Port Stanley, Stratford, Upper Maryhill, Tavistock, and Mornington). Waterloo Moraine deposits are underlain by the regional sandy silt Catfish Creek Till which is an aquitard, but locally may be breached by erosional widows providing connectivity to deeper aquifers (e.g. Bester et al., 2002). The Moraine is locally semi confined where it is overlain by muddy and silty diamictons along its flank. Recharge to the Moraine system is believed to enter mainly through sand hills along the core area of the Moraine. Water percolates through till on the flanks of the moraine by high conductivity windows. Percolating water is believed to also recharge lower aquifers by way of windows in the aquitards and /or fractures within the till. Groundwater flow is generally from northwest to southeast along the core of the Moraine, and toward the Nith and Grand rivers. Local rivers and streams receive discharge from the Waterloo moraine. The groundwater is abundant and characterized by high quality water.
Physiography
Hydrogeological regionSouthern Ontario Lowlands
Hydrogeological context
ReliefThe topography is characteristic of a moraine with an undulating surface.
Area353.00 km2
Lithology
DescriptionBedrock: Waterloo Region is underlain by west-dipping, Silurian-aged dolostone, shale and evaporite (mainly gypsum) of the Guelph, Salina and Bass Islands formations (Armstrong and Carter, 2010). Guelph Formation dolostones outcrop along valleys of the Grand and Speed rivers in the vicinity of Breslau and Cambridge. Due to the distribution of porous structures in Guelph and Salina formations, bedrock aquifers are generally only exploited in the Guelph formation in the Cambridge area. Surficial sediment (from Bajc et al., 2014): Overlying bedrock, glacial and non-glacial sediments predating the last major advance of ice into southern Ontario are informally referred to as Pre-Catfish Creek sediment. This part of the sedimentary succession can be subdivided into a lower unit consisting of stony, silty to sandy diamicton, and an upper unit of clast-poor, variably-textured diamicton (Canning Till). Rare occurrences of organic-bearing sediments may overlie Canning Till. Catfish Creek Till, typically an over-consolidated and stony, silty to sandy diamicton containing frequent cobbles and boulders, occurs across much of southwestern Ontario.. Consistent properties and regional distribution make this till an important marker horizon for regional stratigraphic correlation. Catfish Creek Till is locally absent where meltwater channels have downcut through and into underlying sediments (Bajc and Shirota, 2007). Waterloo Moraine sediments both conformably and unconformably overlie Catfish Creek Till. Moraine deposits include widespread stratified sand and gravel that grade upward and laterally into fine-grained sand. Sand also grades upward and laterally into interbedded and laminated mud (silt and clay) and silty to clayey diamicton. Discontinuous sheets of clayey to sandy diamicton (Maryhill, Mornington, Port Stanley and Tavistock tills) and associated fine-grained glaciolacustrine sediments cap the moraine sequence.
Source
Aquifer
AquifersList of aquifers - Surface Waterloo Aquifer - Lower Waterloo Moraine Aquifer - Pre Catfish Aquifers - Bedrock Aquifer

Unit properties

Surficial aquifer media
Typical value:porous
Description Municipal well fields exploit three main sand and gravel aquifers, surface Waterloo Moraine aquifer, a basal Waterloo Moraine aquifer beneath Maryhill Till, and pre Catfish Creek till aquifer.
Source Modeling a Complex Multi-Aquifer System: The Waterloo Moraine, Groundwater
Bedrock aquifer media
Typical value:fractured
Description In the Cambridge area the main bedrock aquifers are in the Guelph Formation. The bedrock aquifer has enhanced secondary permeability and locally behaves as a confined or semi-confined aquifer.
Source Modeling a Complex Multi-Aquifer System: The Waterloo Moraine, Groundwater
Confinement
Typical value:confined - semi confined
Description Waterloo Moraine aquifers can be semi-confined by Marhill and Port Stanley tillsl along the moraine flanks . Aquifers beneath Catfish Creek Till are confined by overlying till. Hydraulic Windows are present within all aquitard units. Bedrock aquifers outcrop locally in the Cambridge area.
Source Methodologies for Capture Zone Delineation for the Waterloo Moraine Well Fields, University of Waterloo
Surficial sediment thickness
Range: [30 to 150] m
Description The thickness of the unsaturated zone varies from 5 to 40-45 m.
Source Modeling a Complex Multi-Aquifer System: The Waterloo Moraine, Groundwater
Surficial unit hydraulic conductivity
Range: [1e-05 to 0.01] m/s
Description Values used in modelling are based on book values from Freeze and Cherry and corrected through model calibration tests using observed well heads in many hundreds of wells. Frind et al., quote values of 10-3 to 10-6 m/sec within aquifer I and from 10-4 to 10-7 m/sec within aquitard I respectively, with similar values in the other units.
Source Modeling a Complex Multi-Aquifer System: The Waterloo Moraine, Groundwater
Methode Litterature review
Regional precipitation
Range: [780 to 1000] mm/y
Description Average annual precipitation of 780-1000 mm
Source Methodologies for Capture Zone Delineation for the Waterloo Moraine Well Fields, University of Waterloo
Regional recharge
200 mm/y Range: [150 to 450] mm/y
Description 150-250 mm/yr Recharge to the Moraine system is believed to enter mainly through sand hills along the core area of the Moraine. Lower and middle aquifers are believed to be recharged by way of windows in the aquitards, fractures within the till fabric, or both.
Source Modeling a Complex Multi-Aquifer System: The Waterloo Moraine, Groundwater
Hydrogeological unit potential
Description The average extraction rate from all well fields is 0.97 m3/s or 0.31 X 10s m3/year, equivalent to about 15% of the total recharge (Martin and Frind, 1998).
Source Modeling a Complex Multi-Aquifer System: The Waterloo Moraine, Groundwater
Groundwater usage
Typical value:agricultural - domestic - industrial
Description Upper Waterloo Aquifer: The total permitted water taking from these well fields is 773 L/s with an average pumping rate in 2012 of 427 L/s. The transmissivity of the upper aquifers typically ranges from 1300 m2/day to 4500 m2/day. Lower Waterloo Aquifer: Transmissivity estimates in the vicinity of the well field range from 1060 m2/day to 1970 m2/day. Pre-Catfish Creek sediment: Produces up to 300 L/sec, and the transmissivity of this aquifer ranges from about 130 m2/day at the Greenbrook well field to greater than 4,000 m2/day at the Strasburg well field.
Source Towards a Management Plan for the Waterloo Moraine: A comprehensive Assessment of its Current State within the Region of Waterlo
Aquifer vulnerability
Description The unconfined upper Waterloo aquifer is more vulnerable to surface contaminations than the lower Waterloo aquifer and sub-Catfish Creek Till aquifers. Chloride detected in aquifers at depth beneath regional aquitards (Bester et al., 2006) could be from bedrock or from surface road salt.
Source Groundwater contamination in the Kitchener-Waterloo area, Ontario
Threats
Description Encroachment of urban growth and development across the recharge area of the Waterloo Moraine which lacks a surface aquitard. Road de-icing salt, nitrate, and other contaminates from nonponctual sources and ponctual sources.
Source Towards a Management Plan for the Waterloo Moraine: A comprehensive Assessment of its Current State within the Region of Waterlo
Groundwater Quality
Typical value:fresh
Description Natural water quality is good. Chloride and nitrates have been detected in water and are commonly dealt with through mixing of water and dilution. In 1989 the Elmira well field was closed due to contamination by the chemical n-nitrosodimethylamine (NDMA) and the town of 8,000 people lost its only potable water supply. The Greenbrook well field was closed temporarily in 2005 until mitigation strategies were put in place to protect the well field from a plume of 1,4 dioxane migrating from an old landfill.
Source Modeling a Complex Multi-Aquifer System: The Waterloo Moraine, Groundwater