The U. S. Army Corps of Engineers held an Open House at the Truman Visitor Center in Warsaw to assure Benton and Camden County citizens living below Truman Dam of the dam's “structural integrity” and to explain the reasons for downgrading the dam's classification. Jim Sandberg, Operations Project Manager, spoke and answered questions in behalf of the Corps.
The U. S. Army Corps of Engineers held an Open House at the Truman Visitor Center in Warsaw to assure Benton and Camden County citizens living below Truman Dam of the dam’s “structural integrity” and to explain the reasons for downgrading the dam’s classification. Jim Sandberg, Operations Project Manager, spoke and answered questions in behalf of the Corps.
The event on March 13 offered citizens in the downstream area from Truman Reservoir’s huge earthen and concrete dam an opportunity to fully understand both the reason for the change in classification for Truman Dam as well as the true implications for those living on Lake of the Ozarks and beyond. Those in attendance could see the display boards of data about Truman Dam operation and understand both the risk-mitigation plans as well as the disaster recovery plans created by Benton County Emergency Management office.
The latest Dam Safety Action Classification (DSAC) places Truman at a level two. A DSAC 2 classification specifically states:
Dam could fail during normal operations;
Likelihood of failure during an incident or event is too high; or
Potential consequences are high. Additional studies required.
The DSAC 2 classification does not mean the dam is about to burst or has a fatal flaw. In fact, the word “fail,” as Sandberg explained, refers to a rain event so extreme and lasting for so long that in spite of releases, the lake level could still rise and overtop the dam, a condition known as “overtopping.” The word “fail,” Sandberg said, does not refer to the dam completely bursting and releasing the total contents of the lake suddenly.
During the question and answer period at the Open House, one citizen even asked about a terrorist attack to the dam. Sandberg quickly allayed fears about any sort of terrorist attack by explaining that a bomb blast would have to be so massive in order to affect a dam of Truman’s dimensions as to be impossible to deliver. Furthermore, transmitted up, the energy of a bomb blast would have little effect on such a structure. However, the Corp also maintains a current threat assessment and defense plan for terrorism threats.
The second element causing the DSAC 2 classification is “potential consequences are high.” Truman is unique in that it stands above a population of 90,000 with properties valued at $11 billion, making the potential for loss of life and property downstream greater than those other dams. That, according to Sandberg, is the primary reason for the DSAC 2 rating. The flood-control dams upstream with similar designs and ages are rated higher than 2 because there are fewer people and houses in the inundation area below each of those dams. Those dams are also capable of holding back water that would otherwise flow into Truman Reservoir.
According to the Corps, people are central to the new DSAC 2 rating. Methodologies to weigh safety and risk evolve over time. While the Corps inspects and assesses both daily, annually, at five-year thresholds, and each decade, each inspection involves a wider circle of professionals and experience.
One current factor in measuring safety and risk includes recent and increased understanding of how people behave during flood events, and that understanding of dam operations and changing circumstances downstream dictates a different and more conservative approach to disaster preparedness, requiring a reduction from a DSAC 4 to a 2. However, the change in classification caused alarm.
Another cause for alarm may be the public’s perception as the road beyond the Visitor Center to and across the dam has been often closed recently. When asked about the timeline and the work being done, citizens learned the road may be closed periodically for up to 3 years as turbines and other upgrades continue to be made, but these are unrelated to the dam’s integrity. They are routine except that such maintenance and mechanical work disrupt the routine of Benton County’s citizens.
Even though no structural mediation is required, the increased population and property valuation downstream call for improved notification systems. In Benton County, the RAVE mobile safety is available by going to bcmoem.com and clicking on RAVE. Camden County’s citizens use ema65020.org and sign up using the Nixle Widget, or citizens can text their ZIPCODE to 888777 from a mobile phone. This alert would only sound in the event of a breach. The alert would occur hours before the breach and after evacuation orders from city and county authorities, including those at Bagnell, had been issued. Once that alarm sounds, citizens still have hours before water reaches them. One estimate puts the time at 12 hours before Truman waters reached Bagnell. The Corps’ inundation map places estimates for water travel in case of catastrophic failure at two hours to reach Warsaw and ten hours to reach the 40-mile marker on Lake of the Ozarks.
Along with emergency alert systems for Benton and Camden counties, the emergency management agencies as well as all law enforcement and emergency medical departments hold a detailed weekly telephone conference-call that insures any disaster moving downstream will be handled appropriately and quickly to minimize loss or danger.
The United States Army Corps of Engineers and The Federal Emergency Management Agency (FEMA) are separate agencies, but they do have some coordination on issues. The Corps does not expect the new classification to have any impact on FEMA flood maps. In response to a citizen’s question, Sandberg offered the new rating should not affect property values either.
The Corps offers to answer additional questions the public may have and wants citizens to know “Truman is fine, its structural integrity is intact.”