Groundwater Monitoring and Mapping

Groundwater is monitored and observed through the use of monitoring wells and water quality samples. Hydrogeologists install monitoring wells to better understand where the water is beneath the surface. Wells can be drilled deep into the earth, shallow near the surface, or anywhere in between. 

Once installed, a well can be used by hydrogeologists to monitor groundwater. Hydrogeologists are able to measure the distance from the earth’s surface to the water table. They can also test water quality and other more complicated data. For example, if water is pumped from a well for an hour and then pumping stops, you could measure how long it takes for the water level to return to normal. Combined, this information gives hydrogeologists the data they need to estimate the location and quantity of groundwater. Given enough data, the water table for a site or region can be mapped. More recently, advanced technology such as remote sensing and isotopic fingerprinting has been developed which can more precisely estimate where the groundwater is located below the surface.

In Alberta, the Government of Alberta (GoA) has a team of hydrogeologists who install and operate monitoring wells across the province. Additionally, Natural Resources Canada (NRC) is mapping the major aquifers in Alberta. There remain some data gaps around groundwater. The GoA, Alberta Environment and Sustainable Resource Development (ESRD), and academia have studies that are aiming to fill many of these gaps.

 

Alberta Environment and Sustainable Resource Development (ESRD) Groundwater Observation Well Network (GOWN)

The GoA operates over 250 monitoring wells across the province, forty of which transmit data in near real-time to ESRD and 177 used to monitor water quality [1]. These wells have sensors that continuously record groundwater levels. The information collected by the GOWN is used for ESRD’s State of the Environment reports. 

The purpose of the GOWN is to create a baseline for groundwater levels in Alberta. Once there is an extensive baseline, the wells can monitor activity to see is human influence is causing fluctuations in the elevation of the water table. ESRD took over the GOWN from the Alberta Research Council in 1982 which at that time included 55 provincial wells and 90 wells in the oil sands area. To date, the data have been used to map the water table and the distribution of chemicals in groundwater within Alberta; assess industrial and agricultural impacts on groundwater; observe long term changes in water levels to examine the impacts of drought; and assess the groundwater/surface water interactions [2].

 

Natural Resources Canada Groundwater Mapping Program

NRC is currently conducting a groundwater study to map the groundwater in Canada. The study began in 2002 with the purpose to map 30 of Canada’s most significant aquifers, three of which are in Alberta, and create an inventory of their size, location, natural quality and sustainability. This requires three-dimensional data for accurate aquifer mapping. Most of the data comes from the remote sensing capabilities on satellites. Another new technology, isotopic fingerprinting, is also used in this study to evaluate groundwater quality. In this method, isotopes are used to identify the origin of exotic geochemical anomalies in the aquifers. To date, 19 aquifers have been mapped. The project’s planned completion date is 2025. 

In Alberta, the Paskapoo Aquifer, Buried Valley Aquifer System, and Milk River Aquifer have been mapped. In addition, the Upper Cretaceous Aquifer System, the Judith River Aquifer, and the Inter-till aquifer system will be mapped by 2025. Eventually, there will be a full network which, in association with provincial agencies, will include Canada’s entire aquifer network. 

 

What are the data gaps related to groundwater in Alberta? 

Groundwater is not studied as much as surface water since it cannot be seen directly. Studying groundwater can be time consuming and costly, making it difficult to study. Some of the data gaps related to groundwater in Alberta include information on: groundwater-surface water interactions, water well databases and groundwater chemistry.

Consumptive groundwater use is the amount of groundwater that is pumped which is not returned through recharge (water on the surface that enters the groundwater system) 

There is a relatively little known about groundwater-surface water interactions and since monitoring wells are only in some parts of Alberta, groundwater chemistry is also not well known.

There is a high amount of uncertainty with water well databases. Consumptive values are estimated based on recommended pumping rates, but since owners rarely supply this data and are not required to do so, actual pumping rates are not available [3]

The extent of the main buried valley aquifers in Alberta is known (such as the Calgary Buried Valley Aquifer, Beverly Channel Aquifer, Whisky Valley Aquifer, Gregoire Channel Aquifer, and the largest, the Hatfield Valley Aquifer of the Empress Group), but only parts (such as the Cold Lake area) have been mapped in detail [4]. This means that there is knowledge about location and size of the aquifers but further detailed studies and mapping projects are need to fully understand the detailed geology of these aquifers. Certain parts have a higher priority for being mapped because the knowledge is critical in supporting use of groundwater.  

Another major data gap is around groundwater chemistry. Groundwater chemistry is essential when determining if an aquifer is suitable for pumping because water chemistry will determine how the water is extracted. If groundwater is very saline, special pumps are needed and if it has a high amount of arsenic the water will have to be treated once it is pumped. In the prairies, groundwater often has natural trace elements (chemical elements such as arsenic, fluorine, lead or zinc that are naturally present in very small concentrations) that exceed amounts recommended by drinking water regulations. If the groundwater is to be used for drinking water, even more treatment may be needed. 

 In addition to the NRC Groundwater Mapping Program and the ESRD GOWN, ESRD has started other programs in the province to fill data gaps:

  • Groundwater Risk Assessment: Completed by ESRD in 2008, this initiative identified specific risks to groundwater resources. The study revealed a lack of information on groundwater quantity, which puts some southern municipalities at risk for groundwater supply because it is difficult for the province to address water allocation issues without sufficient data.
  • Provincial Groundwater Inventory Program: This program was launched jointly by ESRD and the Alberta Geological Survey (AGS) in 2008. The goal of the program is to evaluate the quantity and quality of groundwater and use this information in sustainable management of groundwater resources. Groundwater mapping shows how much groundwater is available and the location and shape of aquifers. One study from this program was the Calgary-Edmonton Corridor Groundwater Atlas.
  • Alberta Water Well Information Database: In 2012 ESRD released an interactive web-based map where users can find water well information. The goal of this program is to create an exhaustive list all the water wells in the province, as well as, key information such as the location of the well, the depth to groundwater at the well and the geochemistry at each well.

In academia, research is currently being conducted at the University of Calgary and the University of Alberta to fill knowledge gaps on groundwater. Research topics include modelling, recharge, agricultural impacts, and measurements.  

 

Sources:

[1] ESRD. 2014. Groundwater Observation Well Network. Accessed from the web from: http://esrd.alberta.ca/water/programs-and-services/groundwater/groundwater-observation-well-network/default.aspx

[2] Ibid. 

[3] Rivera, A. 2014. Canada’s Groundwater Resources. In print.

[4] Ibid.