PRELIMINARY RESERVOIR IMPACT LINES FOR THE SITE C CLEAN ENERGY PROJECT

Scott McDougall, Michael Porter, Andrew Watson

In the proceedings of: GeoQuébec 2015: 68th Canadian Geotechnical Conference & 7th Canadian Permafrost Conference

Session: Landslides and Slope Stability I / Mouvements de terrain et stabilité des pentes I

ABSTRACT: The Site C Clean Energy Project is a planned third dam and hydroelectric generating station on the Peace River in northeast British Columbia, Canada. The Site C dam would be an earthfill dam with a height of approximately 60 m and would create a reservoir that would be approximately 83 km long. A detailed assessment was undertaken to characterize the potential for groundwater changes, flooding, shoreline erosion, slope instability and landslide-generated waves resulting from the impoundment and operation of the reservoir. The results of this assessment were used to generate preliminary reservoir impact lines that delineate areas of potential hazard. Four preliminary impact lines have been prepared in accordance with guidance provided by the International Commission on Large Dams: a Flood Impact Line, an Erosion Impact Line, a Stability Impact Line, and a Landslide-Generated Wave Impact Line. The reservoir impact lines are linked to recommendations for site-specific analysis, land use, and monitoring. They were intended to support the environmental assessment and the management of risks to public safety, land use and infrastructure. The objectives of this paper are threefold. First, this paper provides definitions for the Flood, Erosion, Stability, and Landslide-Generated Wave impact lines. Second, it describes how preliminary reservoir impact lines were developed for a new hydroelectric project in a geological environment comprising marine clay shales and a complex sequence of fluvial and glaciolacustrine sediments. Third, it illustrates how, when combined with emerging hazard and risk tolerance criteria, impact lines can be used to help communicate and manage geohazard risks around existing and proposed new hydroelectric reservoirs, and potentially along river, lake and marine shorelines.

RÉSUMÉ: la rivière Peace dans le nord-est de la Colombie-Britannique, au Canada. Le barrage du Site C serait un barrage en terre des instabilités de pente et des vagues générées par des glissements de terrain résultant de la création et de l'exploitation du réservoir. Les résultats ont été utilisés pour générer des lignes d'impact préliminaires du réservoir qui préliminaires ont été préparées conformément aux indications fournies par la Commission Internationale des Grands Barrages: une ligne d'impact des inondations, une générée par un glissement de la gestion des risques pour la sécurité publique et celle de l'infrastructure. Les objectifs de cet article sont de trois ordres. Tout d'abord, cet article fournit des définitions pour les quatre types de lignes d'impact. Deuxièmement, il décrit comment les lignes d'impact préliminaires du réservoir furent développées pour un nouveau projet de centrale hydroélectrique dans un glaciolacustres. Troisièmement, il illustre comment, lorsqu'elles sont combinées avec des critères de tolérance de dangers et de risques liés aux dangers géologiques à proximité des réservoirs hydroélectriques existants et futurs et aussi potentiellement le long des rivages de rivières, de lacs et côtiers.

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Cite this article:
Scott McDougall; Michael Porter; Andrew Watson (2015) PRELIMINARY RESERVOIR IMPACT LINES FOR THE SITE C CLEAN ENERGY PROJECT in GEO2015. Ottawa, Ontario: Canadian Geotechnical Society.

@article{523,author = Scott McDougall; Michael Porter; Andrew Watson,title = PRELIMINARY RESERVOIR IMPACT LINES FOR THE SITE C CLEAN ENERGY PROJECT,year = 2015}