Dam Inspections and Emergency Evaluations: Tips and Tricks from a Dam Safety Engineer

The current Virginia Impounding Structure Regulations require that a professional engineer licensed to practice in Virginia perform safety inspections according to the following schedule:

High Hazard Dams:  once every two years

Significant Hazard Dams:  once every three years

Low Hazard Dams:  once every six years

All dams:  after an overtopping event or after flows cause damage to the auxiliary spillway.

In years when a licensed professional engineer is not required, the dam owner is required to perform the inspection and submit the Annual Inspection Report.  In this presentation, dam owners and operators will be instructed on common deficiencies observed at dams and why they may lead to potential safety issues.  Photographic examples will show how the deficiencies may appear and recommended methods to monitor/repair them.   Typical operation and maintenance methods that can help prevent such deficiencies will also be discussed.  The intent of this presentation is to provide tips and tricks to perform an effective safety inspection and how to properly document their findings.

Furthermore, the Regulations require all dam owners to develop and maintain a site-specific Emergency Action Plan (EAP).  Every EAP is to include a discussion of how to detect, evaluate, and classify a potential emergency situation.  When an emergency situation is classified, it is assigned an emergency stage which then instructs the roles and actions of specific individuals for that event.  It is imperative that the EAP include discussion of potential dam failure mechanisms that may occur during a sunny day event (i.e., an emergency developed without heavy rainfall).  This presentation will display a table of common failure mechanisms and how to determine the appropriate emergency stage for each.  Photographs will also display how the failure mechanisms may appear in the field.  The table in the presentation may be provided to dam owners to include in their EAPs.  While it is recommended that a dam safety professional assist in determining the proper emergency stage, it is important for dam owners to understand how to identify and classify potential emergencies since they are ultimately responsible for classifying an emergency and activating the EAP.