Dam incident planning

The Federal Emergency Management Agency in the US recently published its Dam Incident Planning Guide in an effort to support state, local, tribal, and territorial emergency managers in planning for dam incidents and failures. 

The guide summarises the concepts that a community should consider when creating dam incident-specific elements of local emergency operations plans. It builds upon Comprehensive Preparedness Guide 101: Developing and Maintaining Emergency Operations Plans and provides guidance for dam owners and operators on how to engage with emergency managers prior to an incident to ensure a well-coordinated response. It also includes a general template for a community dam incident plan that can be adapted to meet each community’s needs.

Within the document the term “dam incident” refers to dam failures and other incidents that have the potential to harm downstream populations and/or infrastructure. It states that: “a dam incident is an impending or actual sudden uncontrolled release or excessive controlled release of water from a dam breach or a failure of a critical appurtenant structure that impounds water such as a saddle dam or spillway structure. The release may be caused by damage to or failure of the structure, flood conditions unrelated to failure, or any condition that could affect the safe operation of the dam. The release of water might endanger human life, downstream property, or the operation of the structure. All dam failures are “dam incidents”; however, not all dam incidents are the result of failures”.

Spillway failure at Oroville Dam In California in February 2017 led to the emergency evacuation of more than 188,000 people. (Photo courtesy of California Department of Water Resources).

Identifying all responsible parties

During the planning process, FEMA says that community planners should identify government agencies, non-governmental organisations (NGOs), private sector entities, and individuals who are directly responsible for emergency response and support services during a dam incident. These entities should then be considered for inclusion in the collaborative planning team and have clear roles and responsibilities in the plan. The planning process should also result in a clear management structure for coordinating and deploying essential resources. 

The potential consequences from each dam incident vary by the dam type, downstream characteristics, affected populations, infrastructure, and economies. Dam incident plans must be scalable and include considerations for incident detection, evaluation, and emergency-level determination (i.e., severity of the incident), as well as notification and communication processes, emergency actions, and post-incident recovery efforts. 

FEMA says that plans created using this guide will enhance a community’s ability to work collaboratively with dam owners and operators, neighbouring communities, private sector partners, and governmental agencies.

The complete guide can be downloaded at https://www.fema.gov/media-library/assets/documents/184884

Logging incidents

The importance of emergency planning is illustrated by the Association of State Dam Safety officials’ (ASDSO) Dam Safety Incident Database. This provides basic information on dam safety incidents to ASDSO members, dam safety stakeholders, the media and the public. In 2010, ASDSO began to gather dam safety incident information (both failure and non-failure) from the state dam safety programmes, and some states have been able to provide historic incident information. ASDSO says the database is not considered comprehensive of all dam safety incidents, and reflects only the data that it has been able to collect, but it is continuing to work on this and provide as much information, both current and historic, as possible.

Currently the database lists 1062 incidents across the US (both failure and non-failure). Since April 2000 there have been 235 incidents, of which 134 were dam failures.

For more information see https://damsafety.org/incidents