Hey there, time traveller!
This article was published 5/12/2012 (1693 days ago), so information in it may no longer be current.
As a retired Manitoba Hydro engineer previously involved in the planning of Pointe du Bois, I feel it is my responsibility to let the public and ratepayers know that I am troubled by Hydro's decision to replace its spillway. I have had occasion to examine the 1995 to 2002 studies Hydro claims underpin the decision to replace the spillway at Pointe and, while appropriate for their purposes at the time, I found them at far too low a level of detail and accuracy to support this $400-million decision.
This is a big decision: $400 million, creating no direct or indirect revenue. The level of detail and accuracy of the evidence supporting it should therefore be proportionately high.
While I am not a dam safety expert, I think I know enough about the subject to appreciate it when red flags go up, and in this case I have seen them go up just about anywhere I looked.
Manitoba Hydro does not appear to have a document with a detailed account of the decision-making process. A document that sets down all the essentials and shows the line of reasoning from data to conclusions is logical, clear and presented in an open and transparent manner.
The Canadian Dam Safety Guidelines, which the corporation cites as the reason for the need to replace, specifically warn against creating an "imbalance between the costs incurred and the risk reduction achieved." In this case, however, one must ask: is it even clear that the spillway replacement would entail any reduction in the overall risk to life?
Indeed, to what extent does the existing dam pose a flood-induced risk to life?
To help answer that, the guidelines ask three questions: what can go wrong?; what is the probability of this happening?; and if it should occur, what are the consequences?
Engineering consultants studied some of this from 1995 to 2002. The guidelines state that "(t)he simplest and most conservative procedures may be applied as first approximation," and I found these studies to have all the signs of being just that, "first approximations."
For the purposes at the time, the level of all these studies was appropriate. But how can such low-level studies possibly be appropriate for the present $400-million decision?
The guidelines' paramount question about any existing dam is "is it safe enough?" To address this, should the answers to the above three questions of the standards-based approach all prove inconclusive, alternative remedies must be sought, and should none be found, one must ultimately turn to the guidelines' risk-based approach to dam safety. But it would appear that Hydro has neglected to do that.
Manitoba Hydro owes the public a detailed explanation of this decision.