Dam Failure Case Study: Santa Clara Dam (Utah, 2012)

In September 2012, a series of rainstorms moved across southwestern Utah. On the morning of September 11, a debris basin formed by the Santa Clara Dam filled to an elevation that was 9 to 10 feet below the spillway when the city public services director visited the dam to monitor its performance. Nothing unusual was noted during this visit, and the director left the site to check on conditions in other areas of the city. When he returned 30 minutes later, what he found elicited a completely different response. Water from the reservoir was flowing into rodent burrows through the dam resulting in several concentrated leaks on the downstream face. Internal erosion of the dam by these concentrated seepage points ultimately led to the complete breach and failure of the dam. The released reservoir caused damage to 61 homes, 16 businesses, and city infrastructure. No deaths or injuries were caused by the failure, a credit to the City’s public services director for his diligent inspection of the dam and rapid activation of the emergency action plan.