Puslinch councillors have good reason to be concerned and to be prepared as both Cambridge and Guelph plan to increase city water supplies in the future.
On July 19, hydrogeologist Stan Denhoed told councillors the cumulative impact affects roughly two thirds of Puslinch Township.
The drawdown radius for City of Guelph wells extends south of Aberfoyle, while the impact radius of Cambridge is also close to reaching Aberfoyle.
Nestlé Waters
Prior to Denhoed’s presentation on that issue, council reviewed the Harden Environmental report on the Nestlé Waters 2016 annual monitoring report.
Denhoed’s report stated the pumping of groundwater from well TW3-80 (Nestlé Waters Canada) could potentially result in lower water levels in the Guelph and Goat Island/Gasport formations and therefore could affect local wells.
“To date, we are not aware of any private well issues because of this,” said Denhoed.
He explained, “This is due to the relatively high transmissivity of the bedrock aquifers, the fact that the Goat Island/Gasport Aquifer is artesian, relatively high recharge rates and the relatively small drawdown of water level compared to the available drawdown in each private well.”
He stated several private wells are monitored by Nestlé Waters Canada and by the Meadows of Aberfoyle Condominium Corporation.
“In our review of the Meadows of Aberfoyle Permit to Take Water annual report we noted that water levels in a private well (Huether) show a decline in water levels over several years.”
The Huether well is a deeper well penetrating the Goat Island/Gasport aquifer.
Denhoed noted the declining water levels observed are consistent with observations made in several other Goat Island/Gasport monitors in reporting by Nestlé Waters Canada.
The response to the pumping of TW3-80 is less in the Guelph Formation and difficult to differentiate from natural water level variations in the overburden aquifer.
Therefore, the impact to wells completed in these formations is unlikely to occur and none have been brought to the township’s attention.
Further, Denhoed stated “there is no indication that surface water levels respond to changes in seasonal changes to pumping rates in TW3-80.”
However, he did note a review of the monitoring data reveals that water taking in the Aberfoyle area continues to depressurize the Goat Island/Gasport aquifer and the Guelph aquifer.
Denhoed recommended a water well survey to be conducted in the Aberfoyle area to identify potential water quality issues arising from wells that are open to the upper and lower aquifers.
Further, he suggested this be part of a township-wide study of multiple aquifer penetrating wells.
Councillor Matthew Bulmer said it is concerning there is continuing discussion on downward trends of the water levels.
Councillor Susan Fielding noted the downward trend, but commented there are several water takers in the area – and so had concern with the impact being attributed to one water taker.
Impact of city water draw
While Denhoed’s primary presentation to council was in regard to the Waterloo Region’s Cambridge East water supply class environmental assessment, it quickly moved into the overall impact of both Cambridge and Guelph to the aquifer beneath Puslinch.
Denhoed stated the focus of the Cambridge East report is the proposed increase water draw of 38L/second over the next 15 years.
This is in addition to the current 187L/second Cambridge is already taking
Those wells are within one kilometre to one-half kilometres of the Cambridge/Puslinch boundary.
The area of influence for those wells extends into Puslinch – “which is why the township is involved in the review.”
He noted the Waterloo Region study only looks at the impact of the additional water draw while the GRCA Tier 3 study looks at the overall impact.
That study shows the area of influence of Cambridge wells extends almost to Aberfoyle.
Denhoed then added the area of influence of City of Guelph wells extends south of Aberfoyle.
“We have these coalescing areas of influence encompassing two-thirds of the area of Puslinch,” he said.
That influence is identified by a minimum of a two-metre drawdown in the lower aquifer.
“The lowest level is a quite amazing aquifer (Gasport) where most of the water is being taken from for the Cambridge East wells, the City of Guelph wells and Nestlé Waters,” he said.
“I think the township is in an interesting position … of being providers of a lot of water. We should be asking for something in return.”
Denhoed said there should be an acknowledgement that the water is being taken from Puslinch and there is an affect on the aquifers under the township.
He believed there should be more study, but not at the township’s expense. Denhoed said the township should approach Cambridge, Guelph and the MOECC.
Recommendations
1. Expand proposed monitoring program by the RMOW by including one multi-level monitoring station near Irish Creek. This will result in four multi-level stations around the lake.
2. Undertake an assessment of the natural environment to provide a “health card” for Puslinch Lake, McCormicks Bog, Irish Creek and associated wetlands. There should be regular updates every two years.
3. Determine the potential impact of multiple aquifer penetrating wells on shallow groundwater system water levels.
4. A review of passive recharge enhancement opportunities and recommendations from the RMOW about how to compensate for net loss of water from the shallow overburden system to the deeper system.
5. Inclusion of threshold groundwater or surface water level on the Permit to Take Water to enact change to water taking should low water level or environmental issues related to pumping arise.
Councillor comments
Councillor John Sepulis asked about the additional study.
Denhoed clarified that he believed the additional study is something the township should request of the Region of Waterloo.
Councillor Ken Roth said that while Denhoed offered a good report “… it is still as clear as mud.”
Denhoed agreed it is a complex issue.
Roth said that during the public meetings, Waterloo Region representatives seemed very cooperative.
“This is our best window of opportunity to do as much testing as possible,” he said.
Councillor Matthew Bulmer asked “just because the aquifer can recover quickly, is this sustainable?”
Denhoed stated the Puslinch area is not like some areas of the southwestern United States where the water recharge is one or two centimetres per year.
“In those areas, the water will never come back,” he said. “Here, if you turned the pumps off, in a few months the water would return to its original levels.”
However, Denhoed said the sustainability is hard to measure until there is an environmental impact.
Mayor Dennis Lever agreed that now is the time to make requests to Waterloo Region.
The mayor was taken off guard by the way water taking is being measured in litres/sec.
Lever said he usuially saw permits to take water being expressed in millions of litres per day.
The mayor said Cambridge is currently drawing at 187L/second which is about 16 million L/day.
Lever said the additional 38L/second increased draw would equal 3.2 million L/day “which is 1.5 times what Nestlé currently takes.”
As a such, the eventual draw will be over 19 million L/day. Added to that is approximately 20 million L/day drawn from Guelph.
“It is really important that we have a better understanding of this,” Lever said.
