Updated modelling says Gibson’s aquifer is in good shape and predicts that it has the capacity to serve the Town if its population doubles to 10,000.A report from town contractor Waterline Resources was released June 7 and discussed at a committee of the whole meeting that same day. The document integrates hydrogeological data collected by the Town since 2013, updates the groundwater modelling and assesses the long-term sustainability of the Town’s water supply, also known as Aquifer 560, under various demand and climate conditions. The investigations undertaken by Waterline indicate that there are three separate “lobes” or sections within the aquifer which are “hydraulically disconnected from each other beneath the ground,” but share a common recharge area, according to Simon Wing, senior hydrologist with Waterline. He presented a summary of the report at the meeting, pointing out that the aquifer recharge area is shared by Gibsons and surrounding rural areas of the Sunshine Coast Regional District. “This update provides all stakeholders – the Town, community members, local governments and the Province – with valuable new information that can guide responsible decision-making about our most precious resource,” Mayor Bill Beamish said in a press release.
“It also provides clear direction for actions we can take today, to protect the aquifer in perpetuity.”The report examined the future of aquifer performance under different population growth and climate change scenarios using MODFLOW modelling software. In half of the simulations performed, it assessed that there was “low risk” that the Town would need to draw down more than 70 per cent of the capacity of wells accessing aquifer water to meet its needs. In each scenario the severity on the pressure on the system was increased. In the final six calculations, the first three were rated as “medium” risk and the risk level to the Town water supply was rated as “high" in the three last and most severe scenarios.
To keep risks of exhausting the available supply of safe water from the aquifer low, Wing recommended that the Town focus on development of wells farther away from tidewater areas, such as Well 6 in the Oceanmount area. The Town is currently building the pumping infrastructure for that well and is also looking at development of a second well that would share the location and infrastructure.Wing noted that looking for well locations in the Gibsons Creek area was another good option. At the meeting, Beamish asked about whether on-ground development is having negative effects on aquifer water quality. Wing responded that water quality is monitored and to date, there is no evidence that land use practices are directly impacting water quality. Beamish commented at the meeting that he wanted to see the information shared with Sḵwx̱wú7mesh Úxwumixw (Squamish Nation).
The report and other background information on Aquifer 560 is available on the Gibsons website.