Puslinch officials are hoping new ground monitoring wells will help ensure the acceptance of a certificate of approval for de-watering material removed from Puslinch Lake.
Hydrogeologist Stan Denhoed explained to council the existing certificate for dredging and dewatering, which the Puslinch Lake Conservation Association has been carrying out since 2005, expires at the end of November.
He said the three existing monitoring wells on the GRCA Olive Grove property at McCormick’s Point are now inaccessible due to the expansion of the de-watering area, and they no longer meet standards.
“It is our recommendation that four new groundwater monitoring wells be installed on site at each of the four corners of the de-watering pond,” Denhoed said in his report.
He explained the dewatering process, which allows the water to either evaporate or drain into the ground, seems to be working for the PLCA, whose members say the lake’s water quality is improving.
It is much less time consuming and expensive and a lot faster than the previous method, which used bags and geotechnical fabrics to drain the water, which was then put back in the lake, he added.
“This is the only method that’s worked,” councillor Dick Visser said, noting he saw a sailboat in the lake this summer for the first time in years. Visser said the dredging is expected to be a 25-year project when all is said and done.
Denhoed agreed the dewatering has been a success for the PLCA, but he stressed the issue is satisfying the province that the process is not having a negative impact on groundwater quality.
“This is not a benign product,” he said, noting the dredged material can contain nitrous, phosphorous and ammonia. He’s proposing the four new wells to ensure the township has taken its “due diligence.”
Council unanimously approved a resolution to pay Harden Environmental $6,090 to install the four new monitoring wells, assist with the certificate of approval process and decommission the three old wells.
