Projects
Swinging Bridge Dam (P-10482) Dam Safety Remediation Project
Emergency Action Plan
The Swinging Bridge Emergency Action Plan (EAP) has been revised to include all affected developed areas along the Delaware River. Following the May 5, 2005 discovery of the sinkhole and activation of the EAP, Mirant initiated immediate coordination with State and local Emergency Management Agencies (EMA) along the Delaware River. The State and local EMAs were informed of the situation at Swinging Bridge Dam and the fact that in the event of a project emergency, their local jurisdictions could be impacted by a rise in the water surface elevation of the Delaware River.
Subsequent to the incident, Mirant has conducted a more comprehensive analysis of the potentially impacted areas of development and has prepared a revised EAP Notification List. The ongoing effort to issue a revised EAP included:
- Mirant has prepared a revised EAP Notification List to include all the potentially impacted jurisdictions in New York, Pennsylvania, and New Jersey, and the Federal interests;
- Mirant convened a telephone conference on June 15, 2005 among all State and Local EMAs to coordinate and clarify the proposed new EAP notification procedures, and discussed what they can expect during an emergency at Swing Bridge Dam. They also responded to questions or specific information needs of the State and Local EMAs;
- Following that initial coordination teleconference with the State and local EMAs, Mirant held an initial Tabletop Exercise of the Swinging Bridge EAP on July 8, 2005 that further fine tuned the necessary actions for the EMAs and other first responders. On July 17, 2006 Mirant and FERC met with county and local EMAs representatives to further discuss evacuation procedures and tour the potentially flooded area in Port Jarvis and Matamoras with reference to the June 29, 2006 flood on Delaware River;
- The Tabletop EAP exercise benefited from good participation by the local EMAs. The notification charts were made more effective as a result of the input and comments by the local EMAs. In addition, Mirant was able to provide clarification and insight to many of the technical issues raised by the participants, which will make the EAP more effective;
- The agenda for that tabletop conference included a training session for participants by FERC representatives presenting a discussion of FERC's Emergency Action Plan Program and the most recent guidelines for coordinating with emergency management agencies and performing exercises; and
- Mirant's consultant completed their hydrologic and hydraulic modeling studies of potential dam breach scenarios under sunny day and flood flow conditions of the Mongaup and lower Delaware Rivers. The resulting inundation mapping was distributed to all of the State and local EMA's on January 31, 2006, and a revised EAP for the Swinging Bridge Project was introduced at a second table top exercise on February 22, 2006.
- A functional exercise of the EAP was conducted on March 23, 2006. Representatives from many of the EMA's were present and energetically played there parts in the failure scenarios that were simulated. The first scenario considered a fair weather breach of Swinging Bridge Dam at about 5:30 am. The second scenario considered failure of Swinging Bridge during a 100-year flood. The most significant observation from the exercise was the need for public education because a dam breach flood will rise rapidly unlike anything anyone has ever seen before.
- The table top and functional exercises provide the opportunity to further clarify the responsibilities, procedures, and actions for any possible emergencies at Swinging Bridge Dam and the areas downstream. With the suggestions for improving the EAP and the results of the supplemental Hydrology & Hydraulic (H&H) analyses, more effective notification procedures have been developed. This includes early warnings based on reservoir levels, rate of reservoir rise, flows in both the Delaware and Mongaup Rivers, and flood forecasts. In addition, a public education program is being implemented to explain the difference between natural flooding and dam failure floods.
A preliminary public education presentation was presented to a core group of county and local EMA's on September 28, 2006. The presentation described the extent of dam breach flooding in comparison to the June 2006 floods. Photographs of various areas were used that showed the depth of flooding in June, and what the depth of flooding could be with a Swinging Bridge dam breach during the Probable Maximum Flood (PMF). The extent of flooding was also shown on maps depicting the Delaware River in the Port Jervis/Matamoras area. Refinements will be made to this PowerPoint presentation with the goal of providing a product that the local EMA's can share with the communities.
The public education program was followed by a Tabletop exercise. The Tabletop exercise demonstrated that the EMA's understand the problem and are now better able to respond to a dam breach situation.
Another functional exercise of the EAP was held on November 2, 2006 at the Orange County Fire Training Center in New Hampton, New York. The functional exercise was a follow-up to the July 8, 2005, February 22, and September 28, 2006 tabletop exercises, and the March 23, 2006 functional exercise conducted for the Mongaup River Hydro System.
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Contact Information
Charles Goggins
Regional Engineer,
Division of Dam Safety and Inspections,
New York Regional Office
Telephone: 212-273-5910 |
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