Southwest Guelph water supply environmental assessment

Guelph’s population is growing and the City is studying whether our local water resources can meet expected demand, particularly in southwest Guelph. We’re looking into whether we can increase capacity at our existing wells and what new infrastructure would be needed to increase water supplies to accommodate expected growth.

The City is starting a Municipal Class Environmental Assessment to determine longer term water supply capacity in southwest Guelph. The study will assess the environmental impacts of using more groundwater resources and the need for and support the design of a groundwater protection system to address drinking water quality concerns related to past operations at the Dolime Quarry.

Southwest Guelph water supply environmental assessment area


  • October 2021: Agency and Municipality Workshop
  • September 13, 2021: Environmental Assessment starts
  • 2021: The Southwest Quadrant Class Environmental Assessment is re-initiated and re-named the Southwest Guelph Water Supply Class Environmental Assessment.
  • 2020: The City initiates the Guelph South Groundwater Feasibility Assessment to investigate the feasibility of an additional groundwater supply well on City-owned land within the Hanlon Creek Business Park. City staff negotiate agreements with the owners of the Dolime Quarry for implementing the proposed solution to protect drinking water
  • 2019: City launches campaign to share proposed solution to protect drinking water with the community, including closing the Dolime Quarry, bringing the site into the City’s municipal boundary, giving control of the quarry’s water supply and building an on-site water management system and creating a new mixed-use residential neighbourhood
  • 2018: A solution to protect Guelph’s drinking water from the potential risk posed by the Dolime Quarry emerges. Another update to the ongoing Water Supply Master Plan is initiated to explore and re-confirm the water supply potential in southwest Guelph
  • 2016: Membro replacement well (a municipal water supply well) drilled to increase the security of water supply and achieve higher pumping rates (up to permitted rate)
  • 2014: An update to the Water Supply Master Plan re-confirms the potential for an additional 4,500 m3/day supply from southwest Guelph
  • 2013-2017: The City is in communication with the Ministry of the Environment, Conservation and Parks and River Valley Developments. This includes confidential mediation to find a viable solution to protect Guelph’s drinking water
  • 2010: Southwest Quadrant Class Environmental Assessment is put on hold due to potential water quality and quantity impacts to municipal wells related to the breach of the aquitard at the Dolime Quarry
  • 2009:  City experts, River Valley Developments (Dolime Quarry owners) and provincial regulators establish a technical working group to explore concerns related to water quality and quantity
  • 2008: Discovery that Dolime Quarry activities have reached the aquitard – the dense layer of rock that protects Guelph’s drinking water
  • 2007: Southwest Quadrant Class Environmental Assessment initiated
  • 2007: Water Supply Master Plan is completed, with a recommendation to pursue groundwater supply in the southwest quadrant of Guelph.

Have your say

Your feedback is an important part of the Class Environmental Assessment. We will engage online and in person with:

  • Partner Indigenous governments, including the Mississaugas of the Credit First Nation, Six Nations of the Grand River and the Haudenosaunee Confederacy
  • Urban Indigenous peoples with ties to Guelph (e.g., First Nation, Métis, Inuit and mixed ancestry Peoples)
  • Residents
  • Other interested persons

We will reach out for related conversations and engagement when and where appropriate to ensure meaningful dialogue. We will use feedback to inform the opportunity and challenge statement, alternatives, evaluation criteria and recommended solution(s).

Technical work will begin before we formally engage with the public, so please check back regularly for upcoming opportunities by visiting, and follow our Twitter and Facebook channels. We anticipate the first public open house to be scheduled in 2024.

The process

This project will follow the Schedule B Municipal Class Environmental Assessment (2015, as amended), which is an approved Class of Environmental Assessment under the Environmental Assessment Act. Due to the long timeline associated with the Operational Testing Program, the project is expected to be completed by late 2025.


2014 Water Supply Master Plan Update

For more information

Dave Belanger, M.Sc., P.Geo. Water Supply Program Manager, Water Services City of Guelph
519-822-1260 extension 2186
[email protected]

Matthew Alexander, M.Sc., P.Geo. Project Manager, AECOM Canada Ltd.
[email protected]