Dam Failure Case Study: Testalinden Dam (British Columbia, 2010)

At approximately 2:15 pm on Sunday, June 13, 2010, a privately-owned earthen dam on a man-made reservoir on Testalinden Creek failed, causing a debris and mud torrent that travelled 7 km downstream to severely impact a number of homes and an agricultural area located 7 km south of Oliver, British Columbia. Fortunately, there was no loss of life. Although the dam was not large and had a very small impoundment, the estimated breach outflow volume of between 20,000 to 29,000 m3 combined with saturated silty soils in the steep downstream channel to produce a very large debris flow that was an estimated 250,000 m3 in size by the time it reached the alluvial fan in the main valley below.
In addition to detailed investigations of the factors that contributed to the Testalinden Dam failure, this failure led to important changes to dam safety regulation and oversight in British Columbia. Over 1,100 dams in the Province were evaluated under a Rapid Dam Assessment (RDA) program, the Provincial Dam Safety Regulation was amended, a new Professional Practice Guideline for Dam Safety Reviews was developed, education and awareness programs were offered to dam owners, and Provincial dam safety reports are now published annually.