Either drill right through the aquifer or dig a shallow trench through dozens of Sardis backyards.
Those are the options for Kinder Morgan’s Trans Mountain oil pipeline twinning through Chilliwack, and city hall wants the aquifer protected.
At Tuesday’s meeting, city council will consider a staff recommendation to send a letter of comment to the National Energy Board (NEB) about construction methods for the pipeline between Watson Elementary and Deerfield Crescent.
In that stretch, the existing right-of-way of the 1953 pipeline runs underneath or near the backyards of approximately 50 residential homes.
Kinder Morgan considered an alternate route along the BC Hydro corridor to avoid the residential neighbourhoods. But the company said BC Hydro said the new pipeline cannot be safely located close to the overhead power transmission lines.
So, to twin the pipeline that already exists under the residential backyards the company has to either use directional drilling or cut and cover.
City hall found out the deep tunnelling construction method proposed by Kinder Morgan would go to a depth of 20 metres in the area. The Sardis-Vedder Aquifer, the source of the city’s drinking water, begins at approximately 10 metres below the ground.
“Staff acknowledges that tunneling will reduce the construction disturbance to area residences,” says a staff report city council will address Tuesday. “However the deep method being considered would increase the risk to the Sardis-Vedder Aquifer both during and after construction.”
In a letter to Kinder Morgan dated Jan. 23, deputy director of engineering Rod Sanderson expressed the city’s “significant concerns” about risk to the aquifer.
In that letter, Sanderson quotes from an environmental consultant’s report that said if the pipeline were to run through the aquifer and there was “a major release, there is a likelihood that parts of the aquifer would be compromised and could not be remediated sufficiently to allow for drinking water supply over a considerable time frame.”
In an interim response letter dated Feb. 15, a Kinder Morgan engineer said because of the aquifer concerns, the company will use open trench methodology over the aquifer from Vedder Road to Unsworth Road.
This will cause considerable disruption to the dozens of homeowners along that route, and at the road crossings, which in that location includes Tyson and Watson roads.
The NEB still has to approve Kinder Morgan’s planned route for the pipeline expansion.
In addition to the residential area, the company had proposed to use the deep horizontal directional drill to cross the Vedder River and adjacent tributaries, including the Browne Creek Wetlands in Yarrow.
However, in a letter dated Feb. 28, the company said that for geotechnical reasons this won’t work so they will use a revised trenchless crossing technology called DirectPipe. Because this revised technology can’t extend as far, the plan is to still begin going under ground on the north side of the Vedder River at the dike, but now an open-cut trench will be used through the Browne Creek Wetlands.
Kinder Morgan is hosting an information meeting on the route and construction activities in Hope on March 7, and a “by-invite” meeting in Chilliwack at the Coast Hotel on March 8 from 6 to 8 p.m.
Two days after the meeting, March 10, is the deadline for Kinder Morgan to file its Plan, Profile and Book of Reference (PPBoR) for the route segments from Popkum to Coquitlam. Notices should go out to landowners on the route and that will trigger a 30-day period during which time people can file opposition.
paul.henderson@theprogress.com
@PeeJayAitch