Dodging a Bullet: Lily Lake Dam and the 2013 Colorado Flood

摘要

This paper is about identification of high risks at a dam, multiple efforts to promptly mitigate those risks, and how the 2013 Colorado Flood severely tested those mitigation efforts. Had the National Park Service (NPS) not made major efforts to improve the safety of the dam before the event, the dam could have failed by lateral spillway erosion and head cutting, threatening the lives of people in more than two dozen homes downstream. This paper and companion presentation are to share the lessons the NPS and others learned in the areas of risk estimation/evaluation, Emergency Action Planning, environmental compliance, Early Warning System, dam repair, monitoring, event detection, incident response, and incident documentation. The paper describes the use of the Bureau of Reclamation - Small Embankment Dam Safety Guideline approach of teamwork, expert elicitation, making conservative assumptions, building consensus, and the leadership needed to move a high risk, but small dam, project forward in a timely manner to reduce confirmed high risk exposure.