Emergency planners can use our tool, the Life Safety Model, to develop emergency plans for floods to help save lives. Technical Director Darren Lumbroso explains the vital role that such tools can play in planning how to deal with the consequences in areas where a dam is at risk of collapsing or an extreme flood is likely to occur.
Teton Dam Flood (photo courtesy of www.waterarchives.org)
There are tens of thousands of large dams worldwide which store water or mining waste. Although the chance of a dam failing is small, the consequences can be deadly. In 1975, the failure of several dams in the Henan Province of China resulted in an estimated 171,000 deaths and 11 million people losing their homes. In 1976, the collapse of Teton Dam in the USA led to 11 deaths and $2 billion of damage. In 2018, the failure of a dam in Laos resulted in at least 40 deaths and 6,600 people being made homeless.
Planning for these catastrophes in advance can help authorities to understand where the risks to people are the highest, reducing the number of fatalities. Even issuing a warning a few minutes before a dam breaks can save a significant number of lives.
HR Wallingford and BC Hydro have developed the Life Safety Model (LSM) that allows authorities to estimate the time needed to evacuate people who live downstream of a dam, as well as the likely consequences in terms of loss of life. This tool can help to ensure that communities are not exposed to unacceptable risks from the operation and maintenance of dams.
The LSM uses a dynamic representation of the floodwave that would result from a dam break and combines this with digital depictions of people, buildings, vehicles and roads. By using the LSM, organisations can view animations of the consequences of a dam break as it unfolds. More importantly, the LSM provides information to emergency planners that allows them to assess when to issue warnings, where to locate areas where people will be safe from the floodwater, how to manage traffic and when to order the evacuation of different communities.
The model provides innovative methods to reduce the consequences of deadly dam failures with HR Wallingford building on BC Hydro’s initial work. The model has been successfully applied around the world to a range of flood events, including coastal surge, river flood, dam failure and tsunamis over the past 20 years.
Recently, dam owners in Canada have used the LSM to check and implement safety upgrades to large dams, as well as develop emergency plans. In Malaysia, the tool has been used to inform authorities of how much time they have available to evacuate people in the event of a dam break, which is being used in improved site exercises. Work is currently ongoing in Peru with the LSM helping the government understand the risks posed to people by dams that store mining waste.
Further in-depth papers on the LSM are available to download from: www.lifesafetymodel.net