September 4-7, 2017, Delft, the Netherlands - 25th Meeting of the European Working Group on Internal Erosion.
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Research needs for improved dam safety risk management of
internal erosion
R.J. Fannin
University of British Columbia, Vancouver, Canada
D.N.D. Hartford
BC Hydro, Burnaby, Canada
Keywords: Dam safety, risk management, internal erosion.
Dams play a central role in the stewardship of Canada’s hugely valuable water resources, for which storage, flood control and hydropower generation are the key national interests. There are more than 10,000 dams across the country, most of which are owned by the federal and provincial governments, electric utilities, industrial and mining companies, irrigation districts, and municipalities. British Columbia, like the provinces of Quebec, Manitoba, Newfoundland and Labrador, and also the territory of Yukon, generates almost 90 % of its energy from hydropower sources. Canada is now the world’s biggest producer of hydroelectric power, generating 350 TWh/year, or approximately 13 % of global output.
Three of the biggest embankment dams in the world, based on reservoir storage capacity, are located in Canada. They represent an enormous investment by Canadian society at-large and, like much of our public infrastructure, these northern-climate embankment dams are ageing. An effect of the ageing process, at susceptible locations, is for water seeping from the reservoir to erode, with time, fractions of soil in the embankment dam. Such internal erosion is probably the greatest, and least understood, risk of failure in embankment dams worldwide.
The industry need is to address the scientific issue of spatial and temporal influences on the occurrence of internal erosion in embankment dams, and more specifically:
• What is the relation between soil type, effective stress and seepage-flow that explains where internal erosion initiates within a zoned embankment dam?
• What explains the time-rate at which internal erosion continues, and hence determines when internal erosion progresses to constitute a significant risk to a dam?
The two research questions are defined by the classic need to develop a theoretical model, calibrate it, verify it, and then validate it against field observations. Drawing upon industry experience with dam safety risk management, and related guidelines for dam engineering practice in Canada, the USA and internationally, we outline a research framework to address the two questions.
R.J. Fannin
University of British Columbia, Vancouver, Canada
D.N.D. Hartford
BC Hydro, Burnaby, Canada
