Aquifer System

Localisation

Carbonate rock


Freshwater aquifer
The Winnipeg Formation is a continuous, extensive geological unit that is composed of shales and sandstones. On the area, the upper and lower sections consist of a northern sandstone facies, a central transitional facies of interbedded sandstone and shale and a southern shale facies. The Winnipeg Formation overlies the Precambrian bedrock and is located below the Carbonate Aquifer which is covered by Quaternary sediments: a till unit followed by a clay layer which is overlain by glaciofluvial sediments. Fresh groundwaters are confined to the northern part of the basin, the eastern Interlake region and parts of southeastern Manitoba. Fresh groundwater is from the subglacial recharge that occurred during the Pleistocene. Freshwater from subglacial recharge is located primarily in an area between the Sandilands and the Red River in southeastern Manitoba and in the Interlake area. There is a subcrop belt of the Winnipeg Formation beneath the Sandilands Moraine, which is a major freshwater recharge area to the aquifer. Freshwater recharge emanating from the Sandilands area flowing to the west and northwest in southeastern Manitoba. The flow direction in the rest of the freshwater portion of the aquifer is from east to west. If the current hydraulic head regime persists, eventually the Interlake area will be occupied by saline water. The freshwater-saline-water interface in the area south of Lake Winnipeg appears to be moving northwards and eventually the zone of saltwater in this area will likely disappear, resulting in a continuous zone of freshwater. As mentioned, portions of the aquifer currently occupied by freshwater are resalinizing by the saline formation waters from the Williston Basin that is moving eastward. The potential for migration of the saline waters into freshwater represents a threat for fresh water which is currently used as a source of domestic water supply in southeastern Manitoba and along the western shore of Lake Winnipeg. The aquifer is a source of high-quality water, but it has locally elevated F- concentrations.
Brine or saline groundwater aquifer
The Winnipeg Formation is a continuous, extensive geological unit that is composed of shales and sandstones. On the area, the upper and lower sections consist of a northern sandstone facies, a central transitional facies of interbedded sandstone and shale and a southern shale facies. The Winnipeg Formation overlies the Precambrian bedrock and is located below the Carbonate Aquifer which is covered by Quaternary sediments: a till unit followed by a clay layer which is overlain by glaciofluvial sediments. Saline and brackish groundwaters extend into the western Interlake region and as far east as the outcrop area south of Lake Winnipeg. The Winnipeg Formation aquifer consists largely of brackish groundwater as the formation dips towards the center of the province. Point-water heads of the Winnipeg Formation indicate the presence of an updip flow out of the Williston Basin from southwest to northeast in western Manitoba and the Interlake area. The Winnipeg Lake is an important discharge area. Saline waters and brines in south-central Manitoba have Cl-Br ratios, which are much higher than the average value of sea water. However, these ratios are also considerably lower than the Cl-Br ratios found in minerals of the Williston Basin suggesting mixing of these two types of water. The interface between saline and freshwater in the unit is complex, and is marked by an increase in Sodium and Chloride levels. Hydraulic head distribution indicates that saline formation waters from the Williston Basin are moving eastward and resalinizing portions of the aquifer currently occupied by freshwater.
Source Project Datasets More info
Lake Saint-Martin - ManitobaLake St-Martin hydrogeological unitsVector Dataset
Basal Clastic Unit (Winnipeg)Basal clastic units (Winnipeg) groundwater compositionVector Dataset
Basal Clastic Unit (Winnipeg)Basal clastic units (Winnipeg) groundwater samplesVector Dataset
Basal Clastic Unit (Winnipeg)Basal clastic units (Winnipeg) hydrogeological unitsVector Dataset
Basal Clastic Unit (Winnipeg)Basal clastic units (Winnipeg) surficial geologyVector Dataset
Basal Clastic Unit (Winnipeg)Basal clastic units (Winnipeg) bedrock geologyVector Dataset
Project Publication More info
Lake Saint-Martin - ManitobaThe Lake St. Martin bolide has a big impact on groundwater fluoride concentrations
Lake Saint-Martin - ManitobaOn elevated fluoride and boron concentrations in groundwaters associated with the Lake Saint-Martin impact structure, Manitoba
Lake Saint-Martin - ManitobaGeochemistry, geology, and isotopic (Sr, S, and B) composition of evaporites in the Lake St. Martin impact structure: New constraints on the age of melt rock formation
Lake Saint-Martin - ManitobaGroundwater resources of the Lake Saint-Martin area, Manitoba
Lake Saint-Martin - ManitobaLake St. Martin impact structure, Manitoba, Canada: Magnetic anomalies and magnetizations
Groundwater flow and chemistry in fractured aquifers, Lake St-Martin areaGroundwater resources of the Lake Saint-Martin area, Manitoba
Groundwater flow and chemistry in fractured aquifers, Lake St-Martin areaHydrogeology of the Lake Saint-Martin impact structure, Manitoba, Canada
Groundwater flow and chemistry in fractured aquifers, Lake St-Martin areaIsotopic characterization of groundwaters in the vicinity of the Lake Saint-Martin impact structure, Manitoba, Canada
PhD Thesis : Groundwater Flow and Transport Model of the Red River/Interlake area in Southern Manitoba
Sustainability of the Bedrock Aquifer Systems in South-Central Manitoba: Implications for Large-Scale Modelling
Groundwater in Manitoba : Hydrogeology, Quality concerns, Management
Groundwater Resources in the Red River Basin Area of Manitoba
Lake St. Martin Impact Structure, Manitoba, Canada: Magnetic Anomalies and Magnetizations