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Groundwater Monitoring


What is the Provincial Groundwater Monitoring Network (PGMN)?

The Provincial Groundwater Monitoring Network is a partnership program with all 36 Ontario conservation authorities and 10 municipalities (in areas not covered by a conservation authority) to collect and manage ambient (baseline) groundwater level and quality information from key aquifers located across Ontario.

During the spring and summer of 1999, low water conditions in many parts of southern Ontario prompted the formation of an inter-ministerial task force to assess drought conditions, determine trigger levels and develop a response strategy. One of the major recommendations was the establishment of a PGMN.

Designed to gather long-term baseline data on groundwater quantity and quality in key aquifers across Ontario, the PGMN was approved by the Ontario Cabinet in April of 2000. Under the funding agreement, the Ministry of the Environment (now Ministry of the Environment and Climate Change - MOECC) was responsible for the administration of the funds and overall project management. In partnership with the MOECC, conservation authorities became responsible for collecting data and maintaining the PGMN wells and monitoring equipment.

There are more than 450 monitoring wells in the network. The information system now has data on both water level and water chemistry.

Where and when do we sample groundwater?

The NVCA currently operates 19 monitoring wells as part of the PGMN at 10 sites within the watershed. These wells measure ambient water levels and water quality from the major aquifers (groundwater-bearing areas) within our watershed. Monitoring wells are instrumented with datalogging and telemetry equipment, which enables MOECC to access groundwater level data remotely. Groundwater levels are recorded hourly at all of the monitoring wells, and corrected for barometric pressure.  Water level data is downloaded twice a year.

Water quality sampling for general chemistry and metals are undertaken annually, occurring every fall. Staff use a submersible pump to collect water samples from a well within our monitoring network following the MOECC sampling protocol. The samples are submitted and analyzed at an MOECC accredited laboratory.

Why do we monitor groundwater quality and quantity?

Groundwater monitoring allows us to track changes in groundwater quality and quantity over time and identify potential contaminant sources and effective remediation strategies. The data collected from these monitoring wells and elsewhere across the province enables an accurate assessment of current groundwater conditions. It provides for an early warning system for changes in water levels (caused by climatic conditions or in response to human activities such as water takings), as well as, provide for an early warning system for changes in water quality from natural or manmade causes. It also provides information for making sound land use planning decisions. An accurate assessment of current and emerging trends in ambient groundwater conditions will allow for the development of scientifically-based policy and groundwater management programs.

What results are we seeing?

  • Initial water quality testing indicates that ambient water quality in our sampled aquifers is good.
  • Chlorides are slightly elevated in shallow aquifers near urban areas suggesting that road salts may be infiltrating into these aquifer systems
  • Groundwater levels fluctuate seasonally with highest levels observed in mid-spring with lowest levels in early fall

Annual Groundwater Monitoring Reports

NVCA's Groundwater Monitoring Reports provide an annual overview of the authority's PGMN program and summarize water levels and water quality results.

Annual Groundwater Monitoring Report - 2015

Annual Groundwater Monitoring Report - 2014