BARRHEAD – To coax a few more years out of the Thunder Lake wastewater at their March 7 meeting, approved a recommendation by public works to cap the amount of incoming volume for operators using the lagoon to 4,366 cubic metres annually and utilize a first come, first-serve policy to control the volume.
It is worth mentioning that Lightning Bay residents do not have to conform to the limit as part of a previous agreement the subdivision has with the county, with the exception that if volumes of the lagoon reach 5,821 cubic metres, or if the lagoon level freeboard reaches 0.6 metres the county will be forced to close the lagoon, at least temporarily, to conform with provincial environmental regulations.
Councillors also added $16,000 to the public works 2023 wastewater budget to install four groundwater monitoring wells.
Public works manager Travis Wierenga said the wastewater lagoon at Thunder Lake has been running at or close to capacity for 20 years.
One of the issues with the lagoon, he said, is that like the county's Dunstable wastewater facility, the Thunder Lake lagoon depends on evaporation, especially in the summer months, to keep volumes at the lagoon down.
To help keep volume levels at the lagoon at a manageable level, Wierenga said the municipality's code of practice is to limit its use to residents from the following communities: the Hamlet of Thunder Lake, Summerlea, Lightning Bay, Campsie Trailer Park, Tiger Lake Estates, Cambarr Estates and Campsie Cove.
He added that the Lightning Bay subdivision constructed the lagoon, and the county took over its operation in 1987.
"As the community constructed the facility, they have an agreement with Lightning Bay to grant their residents unrestricted access," Wierenga said. "They have their own small vacuum truck and a garage opener remote to open the gate. They are supposed to report their loads to us, but it is on the honour system."
He also noted that public works’ recommendations come in light of a capacity assessment report they commissioned Associated Engineering to complete.
To ensure that Lightning Bay residents will continue to have unfettered access while restricting others, public works will swap out the current gate opener with a card access system at no cost to residents.
"The sounding analysis of the lagoon indicated capacity has been reduced by about 30 per cent. Most of that is around the dump structure," Wierenga said.
Wierenga also noted that the lagoon's location does not allow room for expansion, adding it is adjacent to a wetland and it does not have any monitoring wells to ensure the integrity of its cell liner.
"The report also noted that brush is encroaching on the lagoon's berms which could impact the liner's integrity," he said, adding the addition of the four testing wells would also allow the county to determine the condition of the lagoon's lining.
Wierenga noted the report also recommended that incoming wastewater be capped at 4,366 cubic metres per year.
"This should give us enough buffer capacity in the wet years to keep the wastewater below the acceptable freeboard limit and allow Lightning Bay residents to continue to access the lagoon as per the original handover agreement," he said, recommending that the lagoon remain open for eligible users on a first-come, first serve basis.
Of course, Wierenga said that desludging would increase the capacity of the lagoon, adding the report recommends that it be done in the next three to five years.
"But before we spend a lot of money desludging, we should take a hard look at the future of this facility and consider its use," he said.
County manager Debbie Oyarzun agreed, saying they need more data on user usage and the liner's condition before making a decision.
She also added that potential growth in the area also needs to be factored in, noting desludging would only gain them an additional 1,000 cubic metres of annual capacity.
"(The lagoon) can't be expanded, so do we continue to use it, or look at another site? Based on the data we get from testing, that will tell us the condition of the lining along with our growth projections," Oyarzun said.