May 2020 Flood
US Army Corps of Engineers
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May 2010 Flood Cover Photo - Looking back at what happened

What happened during the May 2010 Flood?

During the two-day event in May 2010, some areas received rainfall amounts exceeding 17 inches, the highest two-day total with more than 140 years of record. The Nashville area received more than 13 inches of rain in 36 hours, more than doubling the previous two-day rainfall record set in September 1979.

Nashville flooding May 4, 2010. (USACE Photo by Mark Rankin)Much of the rain fell in areas downstream of the Corps’ flood risk management projects, which made them unable to play a major role in reducing flood crests on the Cumberland River. Record water flow from the Harpeth and Red Rivers, Mill Creek and numerous other tributaries flowed unchecked into the main stem Cumberland River, producing the historic crests observed at Nashville, Cheatham Lock and Dam, and Clarksville.

Three projects set pools of record and maximum water flow release records: Old Hickory, Cordell Hull and Cheatham set a maximum water flow release record. Old Hickory came within 6.6 inches of overtopping the lock wall. The Cumberland River literally overtopped Cheatham Lock and Dam.

The Nashville District Water Management Section and Hydropower Operators at Corps dams applied all of their experience and expertise in a dramatic flood fight. Their tireless and in some cases heroic efforts, prevented a higher crest in downtown Nashville.

How did Nashville District address issues identified in After Action Report? Questions & Answers

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The Nashville District logistics manager can request a “Logistics Planning and Response Team” using ENGLink.  This is now part of the contingency checklist.  The U.S. Army Corps of Engineers Great Lakes and Ohio River Division’s alert and recall roster includes personal contact information for all logisticians within the division, and Logistics Plans and Operations Division.

The Corps of Engineers, National Weather Service and U.S. Geological Survey are charter members of the Tennessee Silver Jackets team, which is a consortium of federal, state and local agencies whose mission is to partner together to mitigate flood risk in Tennessee.  The three federal agencies communicate regularly, even when there is not an ongoing event.  The Corps meets annually with the USGS to develop the annual Cooperative Stream Gaging Program.  We’re utilizing the NWSChat, an Instant Messaging program developed by the National Weather Service, to routinely coordinate our reservoir operation plans with the National Weather Service.  Finally, we installed automated spillway gate monitoring equipment that provides real-time information to the National Weather Service on reservoir releases.

The Nashville District established a new Water Management Center to expand command and control capabilities.  We have updated our 24/7 operations plan with weather and water level thresholds to define when to monitor conditions outside of normal working hours and defined when Water Management elevates its staffing level after hours.  Each operating level has requirements for increased frequency and scope of internal and external communications.

We have installed communication equipment with satellite capability at the federal building and new hardware and software.  This enables water managers to receive stream gage, rainfall and redundant reservoir and tailwater elevation data directly via satellite.  We still receive project data entered by the operators via network.  One thing that we’ve done to improve the redundancy of that system was add a second independent network line at the federal building.   The project operators call the National Weather Service directly to report spillway gate changes.  We are also adding automated spillway gate monitoring equipment at our dams, which provides data directly to the NWS.

While it is a constant challenge to educate the public about how the Corps manages our projects within the Cumberland River system, we have developed and published a water management education series on our website, which describes how the Corps manages flood risk.  A mobile website called River Status was also developed, which makes available key water management information from Nashville District projects and from their accompanying watersheds.  The data is easily viewed on mobile devices, tablets and computers.  We also worked with other federal agencies and the city of Nashville on their SAFE Tool, which stands for situational awareness for flood events.  This tool helps with the city’s flood preparedness response and mitigation efforts.  Public Affairs takes advantage of every opportunity to educate the media about how the Corps manages projects in the Cumberland River system.

Emergency Management Branch had no issues recalling emergency essential personnel (i.e. EM, Senior Leaders) during the 2010 event. The district uses a call tree to recall crisis management team and crisis action team members when necessary. The system improvement that was made after the 2010 event was to create “tiers” on the CMT recall roster. This allows only the essential personnel needed at the time to be notified. The Nashville District also uses the Army e-Messaging System to recall and inform district personnel.  This system has been used effectively a number of times since the flood during inclement weather events.

Water Management has identified subject matter experts to be deployed to the state emergency operations center as needed to brief water management operations during flood events.  The Emergency Management Branch has always had outstanding communications with the Tennessee Emergency Management Agency.  However, we have created the Emergency Management Support Team. This team consists of subject matter experts within the district that supports emergency management during a disaster. As stated above, Water Management subject matter experts will be called to the emergency management branch during an event to provide on-time data to TEMA.

Sandbags are distributed to different locations throughout the district’s area of responsibility. We have the capability of receiving additional sandbags from vendors within 24-48 hours. There has not been any change, nor was there a need for improvement in the way we distribute sandbags to the state in both Tennessee and Kentucky.  We distributed more than 100,000 sandbags to Tennessee within hours of them being requested during the May 2010 flood event.

The USACE Logistics Activity has designated the U.S. Army Corps of Engineers Great Lakes and Ohio River Division and regional logistics manager to be in the chain of responsibility and command and control when the Local River Advisory Committee has been incapacitated.

The Logistics Support Plan is reviewed annually at the district and division levels as part of the Army’s Managers' Internal Control Program.

When the Emergency Management Branch requests the use of a “Logistics Planning and Response Team,” we ensure the team has full access to our ENGLink database. We also ensure they have a seat in the Emergency Operations Center where they can provide Reception, Staging, Onward-Movement, and Integration services.

The “Logistics Planning and Response Team” is granted access to LRN’s ENGLink database through the ENGLink team in Mobile, Alabama.

Weekly project maintenance status and project component (turbines, spillway gates, sluice gates, etc.) availability report is produced by the Operations Division.  This is used to inform district elements of the status of project maintenance and its operational capabilities.  Water Management participates in a formal review of proposed maintenance schedules.  We do this to ensure that routine maintenance does not affect our ability to operate the projects to manage flood risk. In addition, if changes occur to units during the day, project operators will call Water Management personnel and make them aware of any out of service equipment.

We have updated our 24/7 operations plan with weather and water level thresholds to define when to monitor conditions outside of normal working hours and to defined when Water Management elevates its staffing level after hours..  Each operating level has requirements for increased frequency and scope of internal and external communications. The purpose of this plan is to address staffing requirements ahead of an event and to ensure the proper response is taken as a situation develops.

Increased communication between the Corps of Engineers and National Weather Service has enabled both agencies to improve the understanding of technical information and to streamline the exchange of data.  This has been accomplished through the use of NWSChat and routine coordination calls, as well as visits to each other’s operation centers.  We are also collaborating on the development of a Cumberland River Community Model.  When it’s completed, the same model used to evaluate reservoir operating scenarios would be utilized by the National Weather Service to develop its flood forecasts.

We installed communication equipment with satellite capability at the federal building and new hardware and software.  This enables water managers to receive stream gage, rainfall and redundant reservoir and tailwater elevation data directly via satellite.  We still receive project data entered by the operators via network.  One thing that we’ve done to improve the redundancy of that system was add a second independent network line at the federal building.   We have improved our continuity of operations by identifying a secondary location to perform water management operations as necessary.  We are also replicating water management information and storing it in remote locations to ensure data is accessible.

Water Management continues to follow approved operating plans for operating the reservoirs within the Cumberland River Basin. We can and do make adjustments to project operations prior to a rainfall event; however, due to the timing and magnitude of water needed to be released in order to significantly change water levels throughout the basin, it is very difficult to make concrete operating plans based upon predicted rainfall forecasts.

We have participated with the National Weather Service in webinars and teleconferences to receive training on quantitative precipitation forecasts.  In addition, our 24/7 operating plan dictates requirements for monitoring QPFs issued by the National Weather Service when Corps personnel are off duty.

We receive all National Weather Service forecasts through an automated system.  In addition, we coordinate and exchange information through NWSChat directly with the National Weather Service in the development of their forecasts.

We are now fully engaged in the Cooperative Stream Gaging Program with the U.S. Geological Survey and the National Weather Service for maintenance and operation for Corps-owned gages.  The Corps collaborates with both the USGS and National Weather Service on the best locations for gages.  Where economically feasible, gage stations have been modified to provide additional protection from high-flow events.

The District is undergoing a thorough and deliberate revision of the Water Control Manuals that govern operations of our 10 dams. In addition, as a result of the May 2010 rainfall event, some of the project rating curves which help us calculate discharge rates were extended to cover higher stages and gate openings experienced in the May 2010 event.

The Nashville District is undergoing a thorough and deliberate revision of the Water Control Manuals that govern operations of our 10 dams. When changes are proposed to how the Corps operates one of its projects a public review process must be undertaken, which ensures a comprehensive update is completed and that update is open to public comment.

Water Management Response

The U.S. Army Corps of Engineers Nashville District regulates the reservoirs in the Cumberland River Basin.  It sets its primary mission during flood events to protect human life and property by minimizing flood damages. The Corps conducts this mission by managing the outflow of water from flood risk management projects. During these events, the Corps works with federal, state and municipal agency partners.

Cumberland River in Nashville, Tennessee, in early May 2010.Rainfall of 13.57 inches in Nashville May 1-3 shattered the monthly rainfall record for May, which was 11.04 inches. The area received between 13 and 17-plus inches of rain, more than doubling a two-day record set in 1979. The Cumberland River crested at 51.86 feet in Nashville, the highest recorded level since construction of Corps’ flood control projects. The flood event required spillway gate operations at the navigation projects of Cordell Hull and Old Hickory to prevent overtopping of critical structures and losing control of water releases and pushed the Corps’ projects of J. Percy Priest, Cheatham, Cordell Hull, Old Hickory, and Barkley to their limits.

During the height of the event, water managers made minute-by-minute decisions for the operation of 10 projects in an extremely dynamic and dangerous environment. Operators at the projects literally stood on top of the dams and visually inspected water levels, waiting to within six inches of overtopping the gates before opening to release water and prevent overtopping of the dam.

This is a compilation of video from each dam project on the Cumberland River during the May 2010 Flood. (USACE video by Richard Scott)

J. Percy Priest Dam

J. Percy Priest Dam in early May 2010. (USACE Photo by Mark Rankin)On the evening of May 3, Corps personnel recognized water levels were going to exceed the flood storage capacity for J. Percy Priest Lake. Water releases were necessary to prevent overtopping of the spillway gates. At 11 p.m. personnel began monitoring levels on the four spillway gates with instructions to open each gate a half a foot when the water reached the top of the gates. The team experienced an issue with one gate not operating properly, but had it repaired and working by midnight. Project discharges were held to 7,000 cubic feet per second to minimize downstream flooding to the greatest extent possible. This continued through the middle of the day May 5 and contributed to reducing the flood stage at Nashville.

Cordell Hull Dam

Cordell Hull Dam in early May 2010.Events required rapid spillway gate changes to keep the lake from overtopping the the spillway gates. Efforts required close coordination among power plant operators, powerhouse staff, and Nashville District's water managers. Ultimately, Cordell Hull set a new pool record and the lake level came within two inches of reaching the top of the spillway gates.

Old Hickory Dam

Old Hickory Dam in early May 2010.Spillway gate operations at Old Hickory Dam continued day and night. Ultimately, Old Hickory Lake set a new pool record and came within 6.6 inches of overtopping the upstream lock wall.  More than 50 spillway gate changes were made at Old Hickory Dam from May 1-6.

 

Cheatham Dam

Cheatham Dam in early May 2010.As the river level rose quickly on May 2, a group of dedicated Nashville District employees worked tirelessly to salvage equipment from the lock building and move it to higher ground. During this process the river came up so quickly that Cheatham Natural Resource Manager’s office team members had to use a boat to transport lock employees to safety. During this same time period, a Cheatham Lock employee lost his personal vehicle to the flood while assisting fellow employees moving their vehicles to safety. Cheatham Lock and Dam was designed to be overtopped during high flow events.

Barkley Dam

Barkley Dam in early May 2010.The flood event required multiple spillway gate changes at Barkley starting May 2. Extremely high water levels required record gate releases at Barkley Dam, which prevented the lake from reaching a maximum flood control pool and
the possibility of overtopping the dam.

After Action Report

The event exposed inadequacies in the Corps’ system for flood response, especially in the area of communications. A disconnect on the technical information exchange between Corps and National Weather Service contributed to problems with flood crest forecasts.

Click to see the AAR report:

May 2010 Flood After Action Report

Report Appendices

Executive Summary

Cumberland and Duck River Basins: May 2010 Post Flood Technical Report

Cumberland and Duck River Basins: May 2010 Post Flood Technical Report

Click here to see report at USACE Digital Library.

Notable Improvements

  • Nashville District established a new Water Management Center to expand command and control capabilities and revised its 24-hour operations plan with specific triggers for activation.
  • Several updated procedures have been implemented since the flood, including improved inter-agency communication among the Corps, National Weather Service, and U.S. Geological Survey; providing real-time project release information directly from Corps project operators to National Weather Service staff; the 24/7 operations plan for Water Management; and increased flow of information to the public through public outreach.
  • Automatic spillway gate monitoring systems installed at Cordell Hull Dam, Old Hickory Dam, Cheatham Dam, and Barkley Dam.
  • Initiated Silver Jackets program in Tennessee. Its vision is to establish and strengthen partnerships at the local, state, and federal level as a means for developing comprehensive and sustainable solutions to natural disasters.  Through Silver Jackets, the Nashville District has been partnering with the Federal Emergency Management Agency, National Flood Insurance Program coordinator, State Hazard Mitigation officer, and additional federal, state, local agencies, and tribal nations to leverage agency resources and improve communication - including sharing of data, information and expertise, and preventing duplication of effort.
  • Partnered with National Weather Service, U.S. Geological Survey and Metro Nashville to develop flood inundation models and tools for all streams in Davidson County, which were shared with FEMA for inclusion in the Flood Insurance Map update. The tools enabled the city to better predict flood scenarios included in the Nashville Situational Awareness of Flood Events (SAFE) Tool. Inundation models help Metro predict flood stages on Cumberland and Harpeth Rivers, and smaller streams, based on forecasted rainfall. The SAFE project supports the city’s flood preparedness, response and mitigation.

Cumberland River Tributaries Detailed Project Report and Environmental Assessment

Cumberland River Tributaries Detailed Project Report and Environmental Assessment Nashville, Tennessee

Click here to see report at USACE Digital Library.