With the flight restrictions that were placed on pilots that prevented them from flying over the construction zone ( shortly after I posted these aerial pics ) removed, new photos of some pretty interesting conditions on the north bank construction of Site C are again raising concerns. ( photo credit to Don Hoffman)
Hmmm.. The Peace river region has been experiencing some torrential rains this summer, with several major storms causing flooding in the area.And while the weather may change as time goes on, the type of soil and soil conditions, will not.
One can’t help but wonder… is this what happens when you build a dam on ” sedimentary shales surrounded by slippery clays.”? Or is this just what happens when you try to get to the point of no return in an area with known geotechnical challenges?
A recent letter sent to
July 16, 2016
Honourable Mike Morris Honorable Mark Garneau
Solicitor General & Minister of Public Safety Minister of Public Safety
Parliament Buildings, Parliament Buildings
Victoria BC Ottawa, Ontario
V8V 1X4 K1A 0A6
RE: Site C – A Public Safety Hazard
In Sept. 2009, p. 9 Klohn Crippen Berger Ltd. and SNC-Lavalin Inc. Peace River – Site C Hydro Project Reservoir Shoreline Impacts Methodology and Criteria Report No. P05032A02-10-001 *1
made the following statement:
“The uncertainties in predicting both the extent and rate of the reservoir shoreline impacts lead to the proposal to adopt an observational approach for periodically reviewing and updating the reservoir impact lines after the reservoir has been filled.”
This factor should have stopped the project instantly.
Instead the decision has been made to build a dam in sedimentary shales surrounded by slippery clays. Most of us lay people know that 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 would be surrounded by Montmorillonite clay soils which will slide when wet.
Are we really going to build a dam on mud?? Just goggle Teton Dam. The Teton Dam was also constructed in a sedimentary basin. The Teton Dam disaster of 1976 and the 2014 Mt. Polley Dam disaster tell it all.
In a recent report by BC Hydro to BCUC ‘unexpected’ geotechnical problems are acknowledged by the proponent. These include unexpected slope failure on the projects north bank, larger than expected deterioration of shale bedrock exposed during construction and a phenomenon called rock exposed swell.
Local citizens know that the failure of the Peace River Bridge in October 1957 was caused by the failure of the shale bedrock base on the north side of the Peace River.
These factors and the professional opinions employed by BC Hydro need to be examined in detail regarding the safety of human activities surrounding and within the proposed reservoir. There has been no outside examination of these factors. It has not been addressed as of the writing of this commentary.
This outstanding safety concern is further reinforced by the report commissioned by the Honorable Jack Weisgerber, Minister of Energy, Mines and Petroleum Resources in 1991. This report was prepared by the Geological Survey Branch of British Columbia (Quaternary Geology and Landforms of Eastern Peace River Region, British Columbia, *2 by N.R. Catto 1991). 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. This report is brought to the attention of the reader regarding reservoir safety concerns.
These six cautionary quotes were made researching the potential for exploration or exploitation of aggregate sites in the eastern Peace River area:
- “Mass movements, including rotational and translation glacial slides and a variety of sediment gravity flows, commonly occur along all the major streams.”…..Page 2
2.“The high concentrations of montmorillonite and bentonite in the strata, however, together with their poorly consolidated nature, greatly increases susceptibility of these rocks to slope failure following fluvial ( or arthropogenic) undercutting or overloading.”…..Page 2
3.”The clays are generally plastic, susceptible to sediment gravity flow if disturbed, and contain a high proportion of material derived from the local Cretaceous bedrock.”…..Page 5
- “Mass movements in the region can be induced by the fluvial undercutting, natural overloading of the slopes (e.g. by debris flow from above), loss of internal cohesion due to sudden saturation (as was common during June, 1990), or by human activity. Evidence of past colluviation in the region is extensive (Bobrowsky et al. 1991), and extreme caution is required in any effort to exploit or utilize river valley slopes.”…..Page 10
- “Thus, all of the major terrain slopes present in the eastern Peace River Region are subject to slope failure. Extreme caution should therefore be observed in any effort to exploit or utilize river valley slopes.”…..Page 15
6.”Valley slopes throughout the region are subject to slope failure and colluviation, and the development of these sites should be minimized.”…..Page 17 summary excerpt
This message is intended for the politicians and the taxpayers of BC. We are the ‘owners’ of BC Hydro although the Government claims that there is only one share holder.
The taxpayers are unintentionally paying for the largest environmental and economic catastrophe of BC’s 21st Century.
The professional review of the failure of the Taylor Bridge *3, the 2009 statement by SNC Lavelin, the Attachie Slide and the many points made in the 1991 Weisgerber Report *2 are all damning.
Just ask the downstream residents of Old Fort and Taylor how they view their personal safety.
There is ample evidence that this dam poses a serious safety issue. It is incumbent on your respective jurisdictions to conduct an independent professional review to certify that this project would be safe.
Arthur A Hadland
*1 Klohn Crippen Berger Ltd. and SNC-Lavalin Inc. Peace River – Site C Hydro Project Reservoir Shoreline Impacts Methodology and Criteria
*2 Quaternary Geology and Landforms of Eastern Peace River Region, British Columbia
*3 The 1957 Peace River Bridge Collapse, Taylor BC
***More on Arthur and his position on Site C here in this excellent podcast : http://theprovince.com/news/podcast-in-depth-with-ian-austin-arthur-hadland-on-the-site-c-dam
***And this today, from Vaughn Palmer,
“Still, significant risks remain, as Hydro itself acknowledged in a progress report delivered to the B.C. Utilities Commission last month. The report cites the geotechnical risks of building along that stretch of the river, a longstanding concern in the region and a factor in the collapse of the Peace River bridge at Taylor in 1957.
“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.”
It’s bizarre how BC Hydro managed to go ahead with all this,despite knowing full well the geo-technical challenges and risks.
Moreso, it puts even more pressure on the Clark government to call an immediate halt and send this to the BCUC, before anymore is invested.
Or end up just like the government of Newfoundland did on Muskrat Falls…. https://lailayuile.com/2016/06/24/shocking-admission-from-nalcor-energy-ceo-serves-as-chilling-warning-to-bc-government-that-exempted-site-c-project-from-independent-review-of-bcuc/