New Site C photos show continued mitigation efforts on slide prone north slope construction
Finally back to the blog and I apologize for the absence but there is only so much time before winter and I have so much work that must be done outside the new place before fall unleashes its first storms of the season, in addition to my regular work.
Which makes me wonder if the engineers at Site C are praying for an early freeze up north, just so they can get a break from dealing with the slop of geological challenges they face on the north slope.
It was July 21st this year that I first published photos of the failures on the north slope construction of Site C, a mess of slides and water resulting from back to back storms and rain this summer. https://lailayuile.com/2016/07/21/site-c-aerial-photos-show-mess-of-dikeswater-and-slides/
Aerial photos taken then showed that a plethora of dikes and terraces in an effort to mitigate the slides and water were failing.
Locals joked that if it kept up, the new work camp would soon be sliding into the Peace as well, since the area is well-known for slides and the 2009 report from Klohn Crippen Berger Ltd. and SNC-Lavalin Inc. indicated uncertainty.
The areas geological history has also been documented as to the sedimentary makeup and risks, yet Hydro claims all this mess is due to ‘unexpected conditions‘ :
“Key geotechnical risks” spelled out in one unsettling passage in the report include “unexpected shears encountered during construction; deeper than expected relaxation joints; bedding planes worse than expected; larger than expected deterioration of shale bedrock once exposed during construction; and rock rebound/swell.” Sounds expensive.
Hydro says it has taken steps to mitigate those risks, conducting field trials and pressuring contractors to assume some of the financial burden. It has also given contractors leeway “to respond to unexpected ground conditions, potentially through pre-agreed pricing.” Which would put ratepayers on the hook as well.
Nor are these geotechnical concerns merely hypothetical, as the report went on to disclose: “Events associated with this risk have occurred on the North Bank gulley crossing, where unexpected slope failure occurred. B.C. Hydro has been working with the contractor to provide an engineered solution, and expects to address this issue within available funds. Once the main civil works contract is beginning excavation B.C. Hydro will have additional information about this risk.”
One wonders why Hydro considers these to be unexpected conditions, when the governments own report recommended development of these sites be minimized:
“a report commissioned by the Honorable Jack Weisgerber, Minister of Energy, Mines and Petroleum Resources in 1991. Prepared by the Geological Survey Branch of British Columbia, this report was made without reference to the proposed flooding of the Lower Peace River Valley; rather it was commissioned to examine aggregate exploitation within the lower Peace River region. It urged caution: “Valley slopes throughout the region are subject to slope failure and colluviation, and the development of these sites should be minimized.” (Quaternary Geology and Landforms of Eastern Peace River Region, British Columbia, by N.R. Catto 1991).
Which is what makes these new photos of Site C north slope construction and progress still so interesting. It appears all of the original work done by the contractor has and is being redone in yet another effort to control what many say cannot be controlled….nor should it be.All photos courtesy of Don Hoffman & no flight rules were broken when they were taken. Click on each photo for a larger version.
In some of the first photos, one can still see small slides and water channels active during construction. And again,despite what Hydro claims, the geological reports from years past clearly indicate these are not unexpected conditions.
How much is the premiers promise to get this project we don’t need past the point of no return, going to cost British Columbians? I’d respectfully suggest to the BC auditor general, to place this front and centre based on what I have shown here in photos.
We should have had a BCUC review, but the premier said no. Energy Minister Bill Bennett said no. But as the knowledgable and wise Arthur Hadland has stated:
“Instead the decision has been made to build a dam in sedimentary shales surrounded by slippery clays. The shales were mud some 70 million years ago. When you add water and exposure of the shale to air, this supposed bedrock returns to mud. On top of it all, the reservoir is surrounded by Montmorillonite clay soils which will slide when wet.
Are we really going to build a dam on mud? Just google Teton Dam. The Teton Dam was also constructed in a sedimentary basin. The Teton Dam disaster of 1976 and the 2014 Mt. Polley tailings pond dam disaster tell it all. The failure of the Peace River bridge at Taylor in October 1957 was caused by the failure of the shale bedrock base on the north side of the Peace River. (The 1957 Peace River Bridge Collapse, Canadian Geotechnical Society, 2010).
The taxpayers are unintentionally paying for the largest environmental and economic catastrophe of BC’s 21st century.“
I’d argue they are paying for it intentionally, thanks to this government. Might want to ask your Liberal MLA’s and their candidates about this, sooner than later because BC Hydro wants Peace valley residents in the path of construction out before Christmas. Happy Holidays eh?
***In other news, I’ve made the difficult decision to step down from the Political Intel panel on the Jon McComb Show as the time slot does not work with my new schedule on a regular basis. The good news is that I’m working towards having the podcast up and running as soon as possible this fall! Watch for updates and more regular posts as I get back into the swing of things”