Canadian Dam Association Bulletin - Summer 2017 - 25

ABSTRACT
On September 20th and 21st, 2010 Hurricane Igor struck the island of Newfoundland packing
wind gusts up to 170 km/h and precipitation totaling more than 200 mm in many areas. Many
of Newfoundland Power's small hydroelectric facilities were damaged during this event. Two of
the hardest hit systems were Lawn Development (625 kW) on the Burin Peninsula and Port Union
Development (600 kW) on the Bonavista Peninsula. The dam at Lawn, a concrete structure with
buttressing overtopped by 450 m, washing away the downstream buttressing rock fill. The fill
was placed in 1995 to increase dam stability. At Port Union, the primary storage pond reservoir
dam, an embankment dam with a steel core, was overtopped resulting in erosion of downstream
fill. There was also damage to two of three freeboard dykes and an outlet structure on the Long
Pond control dam.
This paper will review available hydrotechnical information from Water Survey of Canada
gauging stations and quantify the event with respect the recorded history. Using the data, a HECHMS model of the system response at Lawn and Port Union is presented and compared with
predictions using residual observations at the site. The paper will further discuss Newfoundland
Power's response and emergency repairs undertaken to stabilize structures on both systems.

RÉSUMÉ
Les 20 et 21 septembre 2010, l'ouragan Igor a frappé l'île de Terre-Neuve avec des rafales de
vent pouvant atteindre 170 km/h et des précipitations totalisant plus de 200 mm dans certaines
localités. Plusieurs petits aménagements hydroélectriques de Newfoundland Power ont été endommagés lors de cet évènement. Les endroits les plus durement touchés ont été l'aménagement de
Lawn (625 kW), situé sur la péninsule de Burin, et l'aménagement de Port Union (600 kW), situé
sur la péninsule de Bonavista. Le barrage de Lawn, une structure en béton avec des contreforts,
a été submergé sous une lame d'eau de 450 mm ; le courant a emporté les enrochements placés
à l'aval en 1995 comme butée pour améliorer la stabilité du barrage. À Port Union, le barrage du
réservoir principal, un ouvrage en remblai avec un noyau en acier, a été submergé ; ceci a entraîné
l'érosion de la recharge aval. Deux des trois digues de fermeture ont également été endommagées
ainsi qu'un ouvrage de restitution à la structure de contrôle du réservoir Long Pond.
Cet article présente les informations hydrotechniques enregistrées par les stations hydrométriques de Relevés hydrologiques du Canada et il quantifie l'évènement par rapport à l'historique
disponible. L'utilisation de ces données a permis de construire un modèle HEC-HMS en vue
d'analyser la réponse des systèmes hydrologiques aux sites de Lawn et de Port Union. Le modèle
est comparé aux prédictions établies à partir des observations résiduelles des sites. Les actions
prises par Newfoundland Power suite à l'évènement ainsi que les réparations d'urgence effectuées
pour stabiliser les structures des deux aménagements sont également discutées dans cet article.

Canadian Dam Association * Summer 2017

25



Table of Contents for the Digital Edition of Canadian Dam Association Bulletin - Summer 2017

Board of Directors
President's Message
Roller Compacted Concrete Buttress at the Site C Clean Energy Project
Hurricane Igor's Impact on Newfoundland Power's Small Hydro
CDA Conference Heads to Kelowna!
CDA Directors & Officers - Call for Nominations
2017 CDA Awards - Call for Nominations
CDA Developing New Ways to Distribute Guidelines
Notice of Annual General Meeting
Time to Renew Your Membership
Buyers' Guide and Trade List
Canadian Dam Association Bulletin - Summer 2017 - intro
Canadian Dam Association Bulletin - Summer 2017 - 1
Canadian Dam Association Bulletin - Summer 2017 - 2
Canadian Dam Association Bulletin - Summer 2017 - 3
Canadian Dam Association Bulletin - Summer 2017 - 4
Canadian Dam Association Bulletin - Summer 2017 - 5
Canadian Dam Association Bulletin - Summer 2017 - 6
Canadian Dam Association Bulletin - Summer 2017 - Board of Directors
Canadian Dam Association Bulletin - Summer 2017 - 8
Canadian Dam Association Bulletin - Summer 2017 - President's Message
Canadian Dam Association Bulletin - Summer 2017 - 10
Canadian Dam Association Bulletin - Summer 2017 - 11
Canadian Dam Association Bulletin - Summer 2017 - Roller Compacted Concrete Buttress at the Site C Clean Energy Project
Canadian Dam Association Bulletin - Summer 2017 - 13
Canadian Dam Association Bulletin - Summer 2017 - 14
Canadian Dam Association Bulletin - Summer 2017 - 15
Canadian Dam Association Bulletin - Summer 2017 - 16
Canadian Dam Association Bulletin - Summer 2017 - 17
Canadian Dam Association Bulletin - Summer 2017 - 18
Canadian Dam Association Bulletin - Summer 2017 - 19
Canadian Dam Association Bulletin - Summer 2017 - 20
Canadian Dam Association Bulletin - Summer 2017 - 21
Canadian Dam Association Bulletin - Summer 2017 - 22
Canadian Dam Association Bulletin - Summer 2017 - 23
Canadian Dam Association Bulletin - Summer 2017 - Hurricane Igor's Impact on Newfoundland Power's Small Hydro
Canadian Dam Association Bulletin - Summer 2017 - 25
Canadian Dam Association Bulletin - Summer 2017 - 26
Canadian Dam Association Bulletin - Summer 2017 - 27
Canadian Dam Association Bulletin - Summer 2017 - 28
Canadian Dam Association Bulletin - Summer 2017 - 29
Canadian Dam Association Bulletin - Summer 2017 - 30
Canadian Dam Association Bulletin - Summer 2017 - 31
Canadian Dam Association Bulletin - Summer 2017 - 32
Canadian Dam Association Bulletin - Summer 2017 - 33
Canadian Dam Association Bulletin - Summer 2017 - 34
Canadian Dam Association Bulletin - Summer 2017 - 35
Canadian Dam Association Bulletin - Summer 2017 - CDA Conference Heads to Kelowna!
Canadian Dam Association Bulletin - Summer 2017 - 37
Canadian Dam Association Bulletin - Summer 2017 - 38
Canadian Dam Association Bulletin - Summer 2017 - 39
Canadian Dam Association Bulletin - Summer 2017 - 40
Canadian Dam Association Bulletin - Summer 2017 - 41
Canadian Dam Association Bulletin - Summer 2017 - 42
Canadian Dam Association Bulletin - Summer 2017 - 43
Canadian Dam Association Bulletin - Summer 2017 - 44
Canadian Dam Association Bulletin - Summer 2017 - 45
Canadian Dam Association Bulletin - Summer 2017 - CDA Directors & Officers - Call for Nominations
Canadian Dam Association Bulletin - Summer 2017 - 47
Canadian Dam Association Bulletin - Summer 2017 - 2017 CDA Awards - Call for Nominations
Canadian Dam Association Bulletin - Summer 2017 - 49
Canadian Dam Association Bulletin - Summer 2017 - CDA Developing New Ways to Distribute Guidelines
Canadian Dam Association Bulletin - Summer 2017 - 51
Canadian Dam Association Bulletin - Summer 2017 - 52
Canadian Dam Association Bulletin - Summer 2017 - Notice of Annual General Meeting
Canadian Dam Association Bulletin - Summer 2017 - Time to Renew Your Membership
Canadian Dam Association Bulletin - Summer 2017 - Buyers' Guide and Trade List
Canadian Dam Association Bulletin - Summer 2017 - 56
Canadian Dam Association Bulletin - Summer 2017 - 57
Canadian Dam Association Bulletin - Summer 2017 - 58
Canadian Dam Association Bulletin - Summer 2017 - 59
Canadian Dam Association Bulletin - Summer 2017 - 60
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