Mill Creek, Puslinch

Mill Creek is a groundwater-fed stream located in the Township of Puslinch, in southwestern Ontario. Mill Creek is part of the Grand River watershed.

The Friends of Mill Creek (FoMC) community group organizes ecological restoration activities on Mill Creek, including a youth stewardship rangers program.

Geographical Location

Mill Creek is located in the centre of the Grand River Watershed in south-central Ontario. Extending into the City of Cambridge and Township of North Dumfries, the City of Guelph, the Township of Puslinch, and the Town of Milton, the subwatershed drains around 104 square kilometres of land. The headwaters begin in Puslinch Township and travel southwest through Aberfoyle, then through Class I wetlands just south of Highway 401. After reaching the Shade’s Mills Reservoir and Dam, Mill Creek outlets into the Grand River in downtown Cambridge near the Grand River Pedestrian Bridge.

Physical Attributes

Aggregate Pits

CBM McNally Pit

The CBM (Canada Building Materials) McNally Pit is located on Lots 25 and 26, Concession 2, in the Township of Puslinch. The CBM McNally East Pit is located adjacent to and southeast of the McNally Pit, on Part Lot 27. Both pits are licensed for extraction of aggregates from below the water table, and the McNally Pit possesses a Permit to Take Water.Aggregates from both sites as well as other local CBM sites are washed and processed at the McNally Pit. While extraction below the water table is occurring, monitoring wells around the perimeter of the pit and a staff gauge measuring surface water elevation are maintained. As per the site’s 2020-2021 Groundwater Monitoring Program, the McNally Pit appears to have no adverse effects on the local groundwater system, but pond levels were above the Early Warning Threshold in 2020 and 2021.

CBM McMillan Pit

The McMillan Gravel Pit is located at Concession 2, Township of Puslinch. It is no longer operational, with extraction stopping in 2004. Tributary 3 of Mill Creek is the closest groundwater discharge to this site and accurately represents the groundwater discharge quality passing through the McMillan Gravel Pit. Benthic macroinvertebrate sampling of Tributary 3 of Mill Creek and calculation of the water quality index based on BioMAP (Biological Monitoring and Assessment Program) methods are used to qualitatively evaluate and monitor the site’s water quality. Analysis started in 1997 before extraction stopped. The 2023 benthic macroinvertebrate sampling did not observe any negative impacts to water quality due to extraction on the site.

CBM Lanci Pit

The CBM Lanci Gravel Pit is located on Part Lot 25, Concession 1, in the Township of Puslinch. Weekly water level monitoring is conducted on the site, and it is licensed for Category 1 Class “A” below-water extraction. Above-water extraction operations began in April 2012 and below water extraction began in July 2013, with no extraction on the site between 2019 and 2022. According to the 2022 Groundwater Monitoring Data, groundwater beneath the pit flows in a generally southwest direction, and site operations did not impact water levels.

CBM Neubauer Pit

The CBM Neubauer Lit is located on Part Lot 27, Concession 1, in the Township of Puslinch. The site’s 2023 Groundwater Monitoring Data noted that overall groundwater levels remained within historical ranges for that year, and that no change occurred to water table gradients nor groundwater flow patterns.

Friends of Mill Creek

Friends of Mill Creek is a volunteer group composed of environmentalists, local industrialists, politicians, landowners and residents focusing on the rehabilitation of the creek. The members meet on the third Wednesday of every month at the Puslinch Community Centre. The community-based organization was founded to implement some of the recommendations of the Mill Creek Subwatershed Study, but its overall goal is to maintain Mill Creek’s status as a cold-water stream. The group began with an assessment of water temperatures in the Aberfoyle area. Friends of Mill Creek have been a part of a variety of projects, including fish biomass sampling, in-stream rehabilitation and trail maintenance, dam removals, reforestation and naturalization, and continued temperature monitoring and water sampling. Please visit for a map of projects.

Don McKay

Don McKay is a former politician who was a councillor for both Puslinch and Wellington County. After his retirement, he continued to stay active in the Puslinch community and was named Puslinch Senior of the Year in 2023. Besides his involvement with the Friends of Mill Creek, he is a member of the Aberfoyle Agricultural Society and the Puslinch Optimist Club.

Mill Creek Student Rangers

Each summer, four high school students are hired as the Mill Creek Ranger Crew members. Guided by a university student Crew Leader, they aid in restoration efforts. For example, the 2005 Crew removed log jams as part of their in-stream habitat enhancement, and the 2015 Crew built stream deflectors for sediment deposition in the Creek. Every cohort summarizes their work in a Ranger’s Report. Please visit here for an example of the Ranger Report.