NASHVILLE, Tenn. (March 11, 2022) – Winter, spring summer, and fall; the U.S. Army Corps of Engineers Nashville District is always thinking about flood preparation. From monitoring forecasts and managing reservoirs to creating and maintaining communication with outside agencies and every task in between, engineers in the Water Management Section work hard 365 days a year to prepare for and mitigate risk from a flood event.
Every day, the water management section focuses on flood management and flood risk reduction for ten multipurpose reservoirs in the Cumberland Basin. Of the ten team members, three engineers are designated as primary water managers. The team actively monitors and manages water levels at each reservoir throughout the Cumberland Basin. It is a constant, balanced, and timely dance of monitoring inflows and determining releases.
Typically, flood risk is at its highest potential during the -winter and spring months. During this time, water levels in the reservoirs are kept lower (if possible), to allow for pool increases by upcoming rainfall events. These lower levels create additional storage within the reservoirs, allowing better mitigation of downstream flooding. During a rainfall event, the releases from storage reservoirs are much less than the inflow into the reservoir. Once downstream conditions subside and the uncontrolled runoff downstream recedes, releases from the reservoir are increased to pass the water and regain storage in the reservoir safely. When the risk of flooding is reduced during the summer months, reservoirs typically maintain higher water levels. The higher summer levels provide a larger surface area for recreation. Additionally, holding the reservoir at higher levels provides insurance water against droughts. Typically, late summer and fall is the driest time of the year, and this is when the reservoir drawdown begins. So, despite a lack of rainfall, there is plenty of water in storage to maintain healthy stream flows for water quality and aquatic habitats.
Anthony Rodino III, P.E., chief of the Nashville District’s Water Management Section describes the balancing of drawdown and refilling as continual throughout the year, “We actively drawdown in the fall to prepare for the upcoming flood season. As the flood season wanes in the spring, we start to allow the water to build back up and store in the reservoir to prepare for the summer fill.”
The water management section also focuses on monitoring rainfall across the area, both short and the long terms. Additionally, they monitor the weather forecast across the area. Randy Kerr, a hydraulic engineer in the water management section, talks about the accuracy of weather forecasting, “Technology has made it where you can better rely on weather updates, however there are still surprise events like the 2010 flood and most recently, the flooding in Waverly.” It is key to understand, that these engineers’ role is to reduce and mitigate as much flood risk as possible. However, it is impossible to reduce all risk; engineers cannot simply empty reservoirs without seriously impacting other multi-purpose benefits provided by the Cumberland River system, such as navigation and hydropower generation.
In addition to direct mitigation efforts, the water management section focuses on building relationships with agency partners (local, state, and federal) and communicating with external and internal stakeholders to work seamlessly together during a flood event. “When we see the potential for a significant flood event to materialize in the region, we communicate early and often to prepare ourselves and other agencies to address concerns,” Rodino said. Robert Dillingham, a hydraulic engineer in the Water Management Section, emphasizes the critical nature of communication said, “It is not possible to over communicate.”
The water management section works with emergency management throughout the year to test capability, to conduct flood exercises and to ensure all possible scenarios have an answer. The flood exercises are designed to prepare leadership for varying scenarios, to stress the system and check decision points, and to ultimately discover any weaknesses in the system. If pitfalls are discovered, the team works diligently to solve the issues.
While the engineers in the Nashville District work tirelessly to prepare for a flooding event, it’s imperative for people in the area to also prepare. Robert Dillingham offers a few helpful tips, shown on the infographic.
Remember, each day, the water management section makes decisions on how much water to release from the reservoirs to best balance the entire water system. It is not possible to reduce all flooding, and it mostly occurs on streams not regulated by the district. “On average, over 75% of the water flowing through downtown Nashville within the Cumberland River is released from flood control reservoirs that we regulate and have control over. Without the USACE reservoir system in place, the Cumberland River would be subject to such extreme high and low flows that the development of the region would look very different,” Dillingham said.
(The public can obtain news, updates and information from the U.S. Army Corps of Engineers Nashville District on 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.
Additionally, for more information on the Nashville District’s Water Management Section, please visit: https://www.lrn-wc.usace.army.mil/