Story by Leon Roberts on 01/14/2016OLD HICKORY, Tenn. Corps of Engineers officials led Nashville Mayor Megan Barry on a tour of Old Hickory Dam Jan. 14, 2016 and provided her with an overview of the district's missions, which include flood risk management, navigation, hydropower, emergency management, and recreation.
Lt. Col. Stephen Murphy, U.S. Army Corps of Engineers Nashville District commander, said meeting with the new mayor of Metropolitan Government of Nashville and Davidson County is about continuing the relationship and partnership with the city.
"I thought the visit went extremely well and we're excited about our relationship with the new mayor so that she understands what the Nashville District is, who we are, where we are and what we do, but especially recreation and flood risk management," Murphy said.
Ben Rohrbach, Nashville District chief of hydraulics and hydrology, briefed the mayor about how the Corps operates the dams and reservoirs within the Cumberland River Basin as a system, and specifically about water management operations at Old Hickory Dam and J. Percy Priest Dam. The two local lakes provide benefits to the mayor's constituents.
Rohrbach explained the unique nature of the May 2010 flood, where more than 18 inches of rain fell in less than 24 hours west of the Corps reservoir projects and directly into the Cumberland Rivers and its tributaries, causing a river rise of 52 feet.
Dams like Cordell Hull, Old Hickory, and Cheatham, classified as 'run of the river' projects, meaning they have very little flood storage capacity, were inundated by the fast rise in water and required that the Corps spill water or risk losing the structure at Cordell Hull and Old Hickory. The water topped the dam and lock as designed at Cheatham Dam.
Murphy explained he believes this is what has led to the misperception that the Corps flooded Nashville. A presentation showing how the damage would have been greater in Nashville had the Corps' projects not been in place was especially enlightening and Murphy reinforced how improvements in technology and processes since then showed great benefits during the recent heavy rains in December.
Prior to the creation of the modern dam projects, from 1826 to 1950, there were 73 occurrences of floods above the 40-foot flood stage and 12 above 50 feet. Since 1951, with the modern dams in place in the Cumberland River Basin, there have only been 10 occurrences of floods above the 40-foot flood stage, and only one above 50 feet the May 2010 flood.
So while the 2010 flood event is a rare occurrence since 1951, Murphy stressed to the mayor the unique nature of the event and the many improvements that not only the Corps, but also many state and local counties have made towards preparing for future events. This includes the Corps' partnering with the city of Nashville on the Situational Awareness for Flooding Events (SAFE) program, an internal mapping tool to help Metro better predict when and where flooding will occur to make decisions.
Freddie Bell, Nashville District's Nashville Area operations manager, led Barry across Old Hickory Dam and provided her details of the district's navigation, flood risk management and hydropower missions.
Barry walked across the lock gate, stopped to watch the dam's spilling operations, and spent time in the the hydropower plant and its control room. She met several employees and asked them questions about their work experiences.
As the tour culminated, the mayor said it's clear to her that the Corps of Engineers plays an important role with flood mitigation in Nashville with all of the assets the Corps manages to make sure the river is at the appropriate levels while being mindful of what is going on upstream and downstream of the city.
"It's been a great education," Barry said about the interaction with Corps officials. "Being out here at Old Hickory Dam reminds me that our waterways play such an important role it's recreational, but it's also moving a lot of the barges that come through, and anything on a barge takes things off of our highways and reduces our traffic."
One barge with cargo equals 15 rail cars or 60 18-wheelers on the nation's roadways.
Murphy also informed Barry that 27 Corps of Engineers recreation areas in Davidson County average 3.6 million visits and visitors spend more than $111 million annually, a great impact on the local economy.
Murphy said it was an honor to host Mayor Barry for the tour. He wanted to ensure that she knows that if she has any questions about the Corps of Engineers or its projects, that he is just a phone call away.
(For news, updates and information from the U.S. Army Corps of Engineers Nashville District go to the district's website at www.lrn.usace.army.mil, on Facebook at http://www.facebook.com/nashvillecorps and on Twitter at http://www.twitter.com/nashvillecorps.)