Canadian Dam Association Bulletin - Fall 2016 - 14

TABLE 3 PROBABLE MAXIMUM FLOOD (M³/S) operated efficiently, the IDF is 120 m3/s. If East Lake dam is removed from the system and the combined PMF is assumed equal to the sum of the PMF for Lake Major and half the PMF for East Lake, the IDF increases by twenty seven (27) percent to 152 m3/sec. the interim, remedial work required to stabilize the existing dam until a new dam could be constructed was identified using a potential failure mode analysis (PFMA) of the dam. The PFMA recommended reinforcing the walls of the fish ladder, placing additional rock shoring along the toe of the dam and installing instrumentation to monitor movement of the dam and the fish ladder as a means to provide the greatest reduction in risk. In November 2014, a high level design was completed and a meeting with both Nova Scotia Environment and the Department of Fisheries was planned to get approval. DAM SAFETY EMERGENCY REMEDIAL WORK A 2012 DSR recommended the Lake Major Dam be replaced due to the deteriorating wooden fish ladder and rotting structural timbers in the dam. In the summer of 2014, Meco was retained to begin work on the conceptual design for a new dam, with the expected time frame for completion possibly upwards of three years. In An early winter flood in December 2014 resulted in a significant spill at the dam. During a 48 hour period, 108 mm of rain was recorded at Halifax Stanfield International Airport. As a result of this rainfall a significant amount of water spilled over the Lake Major Dam at levels not normally observed. The Location PMF (2005) PMF (2011) East Lake 107 86 Lake Major 321 240 14 828981_Stantec.indd 1 Halifax Water DSMS requires completing special inspections of dams after unusual or extreme events. On January 15, 2015 Halifax Water and Meco completed a post-storm inspection of the Lake Major Dam where they observed damage to the fish ladder, which had lost and damaged timbers and one of the walls had shifted inward. Meco assessed the condition as a limited structural failure and noted that although the dam was stable for the time being, the concern was a smaller rainfall event could be enough to cause the fish ladder to collapse resulting in the ultimate failure of the dam. Meco recommended repairs to stabilize the fish ladder should begin immediately. Emergency repairs consisted of filling the fish ladder with rock to prevent the walls from collapsing inward. This operation was not without risk. A misplaced rock or careless movement of the excavator bucket could potentially take out one of the structural supports of the fish ladder and cause a dam failure. During the actual construction, arrangements were made with a local View past issues of the CDA Bulletin online at www.naylornetwork.com/cda-NXT/ 8/25/16 5:54 PM http://stantec.com http://stantec.com http://www.naylornetwork.com/cda-NXT/

Table of Contents for the Digital Edition of Canadian Dam Association Bulletin - Fall 2016

Board of Directors
Board of Directors Nominations
Remedial Work at Lake Major Dam
CDA Conference Report: Otto Holden Generating Station Alkali-Aggregate Reaction Investigation
DSR Bulletin
Icold Corner
Notice of Annual General Meeting
Call for Papers, 2017 Conference
Young Professional Activities
Buyers’ Guide and Trade List
Canadian Dam Association Bulletin - Fall 2016 - cover1
Canadian Dam Association Bulletin - Fall 2016 - cover2
Canadian Dam Association Bulletin - Fall 2016 - 3
Canadian Dam Association Bulletin - Fall 2016 - 4
Canadian Dam Association Bulletin - Fall 2016 - 5
Canadian Dam Association Bulletin - Fall 2016 - 6
Canadian Dam Association Bulletin - Fall 2016 - Board of Directors
Canadian Dam Association Bulletin - Fall 2016 - 8
Canadian Dam Association Bulletin - Fall 2016 - Board of Directors Nominations
Canadian Dam Association Bulletin - Fall 2016 - Remedial Work at Lake Major Dam
Canadian Dam Association Bulletin - Fall 2016 - 11
Canadian Dam Association Bulletin - Fall 2016 - 12
Canadian Dam Association Bulletin - Fall 2016 - 13
Canadian Dam Association Bulletin - Fall 2016 - 14
Canadian Dam Association Bulletin - Fall 2016 - 15
Canadian Dam Association Bulletin - Fall 2016 - 16
Canadian Dam Association Bulletin - Fall 2016 - 17
Canadian Dam Association Bulletin - Fall 2016 - 18
Canadian Dam Association Bulletin - Fall 2016 - 19
Canadian Dam Association Bulletin - Fall 2016 - 20
Canadian Dam Association Bulletin - Fall 2016 - 21
Canadian Dam Association Bulletin - Fall 2016 - 22
Canadian Dam Association Bulletin - Fall 2016 - 23
Canadian Dam Association Bulletin - Fall 2016 - 24
Canadian Dam Association Bulletin - Fall 2016 - 25
Canadian Dam Association Bulletin - Fall 2016 - CDA Conference Report: Otto Holden Generating Station Alkali-Aggregate Reaction Investigation
Canadian Dam Association Bulletin - Fall 2016 - 27
Canadian Dam Association Bulletin - Fall 2016 - 28
Canadian Dam Association Bulletin - Fall 2016 - 29
Canadian Dam Association Bulletin - Fall 2016 - 30
Canadian Dam Association Bulletin - Fall 2016 - 31
Canadian Dam Association Bulletin - Fall 2016 - 32
Canadian Dam Association Bulletin - Fall 2016 - 33
Canadian Dam Association Bulletin - Fall 2016 - 34
Canadian Dam Association Bulletin - Fall 2016 - 35
Canadian Dam Association Bulletin - Fall 2016 - 36
Canadian Dam Association Bulletin - Fall 2016 - 37
Canadian Dam Association Bulletin - Fall 2016 - DSR Bulletin
Canadian Dam Association Bulletin - Fall 2016 - Icold Corner
Canadian Dam Association Bulletin - Fall 2016 - 40
Canadian Dam Association Bulletin - Fall 2016 - Notice of Annual General Meeting
Canadian Dam Association Bulletin - Fall 2016 - Call for Papers, 2017 Conference
Canadian Dam Association Bulletin - Fall 2016 - 43
Canadian Dam Association Bulletin - Fall 2016 - Young Professional Activities
Canadian Dam Association Bulletin - Fall 2016 - Buyers’ Guide and Trade List
Canadian Dam Association Bulletin - Fall 2016 - 46
Canadian Dam Association Bulletin - Fall 2016 - cover3
Canadian Dam Association Bulletin - Fall 2016 - cover4
Canadian Dam Association Bulletin - Fall 2016 - outsert1
Canadian Dam Association Bulletin - Fall 2016 - outsert2
Canadian Dam Association Bulletin - Fall 2016 - outsert3
Canadian Dam Association Bulletin - Fall 2016 - outsert4
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