Warmer water in Puslinch pit concerns local councillors

Puslinch councillors are not just concerned with water temperatures at CBM’s Roszell Road Pit, but the fact the company is now extracting material below the water table.

In June, councillors here received information from Stan Denhoed of Harden Environmental regarding temperature changes in groundwater and surface water at CBM’s Roszell Road Pit.

Council subsequently requested Harden’s information be forwarded to the Ministry of Natural Resources and Forestry, CBM and Groundwater Science Corp. with the request for a meeting.

In his report Denheod wrote extractive activities at the Roszell Road Pit are causing a thermal impact to groundwater and surface water as evident in monitoring data provided by the operator CBM Aggregates.

On behalf of CBM, Groundwater Science Corp. raised issues in regard to the interpretation of the timing and location of below-water-table extraction, interpretation of the natural range of groundwater temperatures and the interpretation of initiation of mitigation.

In 2009, the township and Preston Sand and Gravel participated in a process to resolve outstanding groundwater issues related to the proposed Roszell Pit.

As part of an OMB hearing regarding the pit, a statement signed by Stan Denhoed, Andrew Pentney and Ray Blackport affirmed the importance that the township placed on minimizing the impact to temperature of groundwater discharging to nearby cold water fisheries.

According to township files, there was no additional consultation with the township in this regard and according to the Ministry of Natural Resources and Forestry, no thermal study was completed or reviewed.

In 2014, CBM commenced  below water table extraction in the area outside of the 120m setback.

Denhoed stated he believed this is in contravention to the site plan which stipulates maximum floor elevations for the pit.

Those elevations are above the water table.

Denhoed attributed increased water temperatures to the below water table extraction activity.

This presented a breach in the threshold and mitigative measures need to be enacted, he said.

Natural Range of Temperatures

Denhoed noted there are seven years of background temperature monitoring data collected between 2005 and 2012.

“The only change that occurred in 2013 to cause the temperature variation is the stripping of soil and excavation of overburden. This allows solar energy and cold atmospheric temperatures to conduct through the unsaturated zone and/or to directly affect temperatures of groundwater as exposed in the excavation.”

Initiation of Mitigative Measures

The license condition agreed to by the licensee, the MNRF and the Township of Puslinch is that a 1°C change in temperature is required to initiate additional investigation and/or mitigation measures.

The 1°C trigger is a recommendation from the original hydrogeology study in support of the pit application.

“We understand that some additional monitoring has taken place and that an ecologist has been retained to further evaluate the increase in temperature and impact on aquatic life,” Denhoed stated.

“It is our opinion that discussions with the MNRF, the Township of Puslinch and CBM are warranted to discuss the compliance issues as well as mitigation, if necessary to prevent further thermal impact to adjacent streams.”

Councillor Matthew Bulmer said “situations like this do not help us build trust with the public.”

He agreed “whether you like pits or not there is a need for aggregate … but it is nice to have a system you can have faith in.”

Bulmer wanted council to follow up on Denhoed’s observations and have them compared to the compliance reports filed by the operator over the past number of years.

“It suggests (CBM) has not been operating within their site plan.”

Mayor Dennis Lever was also curious about MNRF’s take on the information … and what they are doing about it.

Bulmer was also curious about the MNRF’s definition of involved agencies which were to be forwarded any information on changes to a site plan of operation – before it occurred.

He stated that in the OMB hearing it stated that involved agencies would be advised in advance if the site plan was to be altered from above ground water extraction to below groundwater extraction.

Bulmer said Denhoed believed the township had not been given this information before the change.

Bulmer added that if the site plan has not changed, the activity certainly has.

Lever stated that in his discussions at TAPMO (Top Aggregate Producing Municipalities of Ontario) he was told “municipalities would always be circulated.”

“However, that doesn’t appear to be the case … or perhaps it somehow fell through the cracks.”

Bulmer said the issue is particularly important in this case with stipulations in place as a result of an OMB hearing.

Councillor Susan Fielding said “it appears the ball has been dropped somewhere.”

She was glad the MNRF is going to be made aware of Denhoed’s concerns on behalf of the township.

Councillor Ken Roth took issue with Groundwater Science Corp.’s response to Harden.

He said while there were comments on the water temperature, there was no mention of CBM’s extraction below the water table, “to me that is a pretty serious breach … but they don’t even talk about that.”

He said all the response from Groundwater Science did was dispute Harden’s calculation of the water temperatures.

“I think this is something that needs to be looked into.”

Lever said council will follow up with the ministry.