Letters are flying between “fed up” Curtis Road residents and the Comox Valley Regional District over odour, drinking water wells and other issues emanating from the Brent Road sewage treatment plant.

The regional district’s Senior Manager of Water/Wastewater Services Kris LaRose has assured Curtis Road residents that construction of an equalization basin to prevent potential winter overflows from the wastewater treatment facility will not affect their shallow wells or local groundwater.

In a letter to the residents association, LaRose also said the equalization Basin (EQ) will be built into the ground, not above it, for seismic safety. And, because he only expects effluent in the EQ basin during the stormiest and wettest days of winter, LaRose added that covering the basin to eliminate odours was not financially warranted.

The Curtis Road Residents Association plans to meet later this week to review and possibly respond to LaRose’s reassuring letter. In the meantime, they have written letters of their own seeking provincial intervention.

Jenny Steel, spokesperson for the residents, said she is waiting to hear back from requests her group has made to the Ministry of Health and the Ministry of the Environment and Climate Change. They are seeking higher-level assurances that the EQ basin’s location will not affect their well water quality and quantity.

Meanwhile, Courtenay-Comox Sewage Commission Chair David Frisch and CVRD staff will meet with the residents, and their Area B representative, Arzeena Hamir, next week for a less formal conversation about the issues.

The sewage commission sets policy for a sewerage system that serves residents of Courtenay and Comox, members of the K’omoks First Nation and CFB Comox. But its treatment plant is located in Area B. Neither the Area B representative or K’omoks First Nations have a voting seat on the commission.

What is an EQ basin and why it’s necessary

During heavy rainfalls in the late fall and winter, stormwater seeps into the sewerage system and increases the volume of wastewater entering the plant by more than three times the average summer flow.

With population growth and increasingly extreme winter weather brought about from climate change, those winter flows threaten to overflow the plant’s current holding capacity. That could mean raw or nearly-raw sewage spilling into the Strait of Georgia, which would violate standards and regulations.

The EQ basin was originally planned for another site on the treatment plant property, further from Curtis Road, but engineers discovered conflicts with existing infrastructure and future expansion plans. LaRose says moving the location now would add “several million dollars” to the cost and delay the project for a year.

“Delay of the project to 2020 would result in another winter of increased potential of plant overflow …” LaRose wrote in his letter.

Why the residents are concerned

Curtis Road residents — about 80 people belong to the neighborhood association — have several concerns about the EQ basin and its location 70 meters from homeowners’ property lines.

The main concern is that any compromise of the basin’s membrane will result in a leak of raw sewage into local groundwater and residents’ drinking water wells.

In his letter, LaRose said there will be more than three meters between the bottom of the basin, including its under-drain and leak detection system, and the top level of groundwater. And he said the CVRD would take additional measures to mitigate potential leaks.

The regional district will engage an arborist to assess trees annually prior to the storm season and remove any trees that have a probability of falling on the basin and tearing the underlying membrane.

The district will also drill a groundwater monitoring well below the basin’s location on the Curtis Road side to test water quality and detect leaks. An under-drain system will be installed with sensors to collect any leakage, which will trigger an auto response to drain the basin if a leak is detected.

Residents have complained about noxious odours from the plant since it opened in the mid-1980s that are at times overwhelming. The new EQ basin will have an open surface area equal to the plant’s existing primary tanks, which were covered in a past attempt to reduce odours.

But LaRose said that due to the limited amount of time the basin will contain untreated sewage — he estimated fewer than 50 hours per year — that no cover for the basin is planned.

“The very significant expense of covering the EQ basin is not seen as warranted,” he said.

What residents are doing

The resident have written to the Ministry of Environment and the Ministry of Health. They want provincial intervention in the sewage commission’s plan to build the EQ basin.

They noted that “prevailing winds and gales could easily cause tall trees (rooted in sand) to topple into the basin resulting in a compromised membrane.” And they noted the risk of an earthquake.

“The mental angst of worrying about whether our drinking water is fouled is an unreasonable interference in the use of our property,” they wrote.

The residents’ goal is to convince the sewage commission to relocate the EQ basin further away from their properties.