US Army Corps of Engineers BUILDING STRONG ® Cooperative Efforts in Nashville Flood Preparedness Jamie G. James, P.E. Water Resources Section Nashville District, USACE July 2011

BUILDING STRONG ® In May 2010 portions of Tennessee experienced flooding of unprecedented magnitude. Damage was widespread in the region, and the city of Nashville was particularly hard-hit. Public agencies scrambled to stay ahead of the disaster and prevent more severe flooding and loss of life.

BUILDING STRONG ® For Comparison:

BUILDING STRONG ® Cumberland River in Nashville May 2010 Flood Inundation Downtown Pennington Bend/Opryland

BUILDING STRONG ® In The Beginning:  The Nashville work began as a result of realized shortcomings during the flood of May ► Communication Between Agencies ► Understanding Data and Wider Implications ► Flood Warning and Response  All were determined to learn and improve readiness.  Discussions began in August 2010 ► Metro Nashville Government ► Nashville District, USACE ► National Weather Service ► U.S. Geological Survey

BUILDING STRONG ® The Concept:  Work as a broad-based team to a common goal.  Control the things under our control.  Support Metro EMS and leaders. ► Prevent loss of life, reduce damage  Use each agency’s strengths. ► USACE – Hydrologic and hydraulic modeling ► Metro – GIS mapping and automation ► NWS – Flood warning ► USGS – Gaging and data  Develop products & applications to provide Metro officials with timely information.

BUILDING STRONG ® Challenges  Ongoing national level efforts to organize (IWRSS), but the framework had not been set.  This is one of the first-of-its-type efforts on this scale.  Scaling the scope of work. ► Needs, Time, Budget  Ensuring a common understanding of the goals, technical abilities and products.

BUILDING STRONG ® Opportunities  We could work within the regulations of the respective agencies to craft a product that was tailored to Nashville.  Previous work around the streams and gaging network gave us a head start.

BUILDING STRONG ® Project Team Nashville District Metro Nashville National Weather Service U.S. Geologic Survey Study ManagerTeam LeadersLocal Staff 5 Engineers Stormwater Division Technicians GIS Specialist Watershed Advisors AMEC Interest and Support of Higher Organizational Levels

BUILDING STRONG ® Process  Bi-weekly meetings to discuss progress and issues that arose.  Constant communication regarding technical issues.  Concentrated on Six Streams in the first phase: Cumberland River, Harpeth River, Mill Creek, Richland Creek, Browns Creek, Whites Creek.  Keep the scope manageable within the time and budget constraints. We could always do more later.

BUILDING STRONG ® Goals  Develop products that will provide Metro Emergency Services and decision makers with the capability to estimate flooding impacts in time to take early action.  Look at flooding extent and timing.  Effectively utilize limited resources to greatest effect during an emergency.  Leverage local and federal dollars to provide the best capability possible, and build upon that later.

BUILDING STRONG ® Study Area

BUILDING STRONG ® Increasing Understanding:

BUILDING STRONG ® Added Functions:  Additional Gages on the Cumberland River and Mill Creek (USGS and Metro).  Review of Forecast Points and Flood Warning Levels (NWS and Metro).  Watershed Advisors for Each Stream (Metro).  Flood Inundation GIS Layers for Each Stream Tied to Forecast Stages (USACE and Metro).  Watershed Advisors Guides for each stream (AMEC).

BUILDING STRONG ® Nashville District Work  Modeling and Mapping of the Six Streams for Metro GIS. ► Cumberland River, Harpeth River ► Mill Creek, Browns Creek, Richland Creek, Whites Creek  Utilization of Available Geospatial Data (GeoHMS and GeoRAS, ArcMap).  Model Multiple Storms to Prepare Inundation Layers.  Provide AMEC with model results and timing for use in Watershed Advisors Guides.

BUILDING STRONG ® Nashville District Work (2)  There were existing models for the Cumberland River, Mill Creek and Richland Creek. ► Updated/calibrated to meet the needs of the study.  Utilization of available geospatial data (GeoHMS and GeoRAS, ArcMap, DEM).  We prepared HMS and RAS models of the Harpeth River, Whites Creek and Browns Creek basins. ► Calibrated to known events and May 2010 where possible. ► Historic records and current high water marks.

BUILDING STRONG ® Nashville District Work (3)  Modeled multiple storms to prepare inundation layers. ► HEC-HMS Used GEO-HMS to collect basin data Calibrated to historic rainfall 1-11 inch, 24-hour rainfall Type II distribution ► HEC-RAS Used GEO-RAS to collect cross section and alignment data Calibrated to historic floods Compared to historic HEC-2 and RAS models Inventoried bridges in the field and obtained TDOT plans where possible Steady flow

BUILDING STRONG ® Nashville Flood Preparedness Inundation Products

BUILDING STRONG ® Results  Additional stream gages allow Metro to monitor river conditions at critical infrastructure.  New GIS layers provide Metro emergency personnel with inundation approximations tied to forecasts, helping to allocate resources and assist with timely evacuations.  Metro GIS Specialists developed an interactive tool to illustrate inundation based on forecasts and layers. ► Public access will be determined by Metro.  Watershed Advisors’ Guides provide information to help stay ahead of the flood.  Phase II is underway.  The flood preparedness tools will continue to evolve. ► Flood Damage Analysis ► HEC-RTS  Phase III is being planned.

BUILDING STRONG ® HEC-RTS (Real-Time Simulation)

BUILDING STRONG ® HEC-RTS  Provides a real-time simulation capability.  RTS is proposed for the Cheatham Reach of the Cumberland River, which includes Nashville.  Joins the hydrologic and hydraulic models to allow simulations of basin rainfall response and estimation of stages at the flow prediction points identified in the model.  Prepared by USACE for Metro, to be reviewed by, and made available to, NWS.  Scoping meeting was July 19.  Delivery is planned for next spring.

BUILDING STRONG ® How can these efforts be applied in other locations?  One product does not fit every community. We developed this work with scalability, portability and adaptability in mind.  If a flood-prone community has GIS capability, we can duplicate this work for their streams, on their system.  If a flood-prone community does not have GIS, we can create paper maps to illustrate the flood inundation levels.  In either case, new gages can be installed to monitor streams near critical infrastructure. ► Automated warnings can be applied.  A Flood Warning and Emergency Evacuation Plan can be developed to help with critical decisions during flood emergencies.

BUILDING STRONG ® If you have questions regarding USACE programs:  Contact: ► Trena Bradshaw – District Outreach Coordinator ► Phyllis Kohl – Floodplain Management Services Program

BUILDING STRONG ® Questions?