US Army Corps of Engineers

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Cooperative Efforts in Nashville Flood Preparedness

Jamie G. James, P.E.

Water Resources Section

Nashville District, USACE

July 2011

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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.

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For Comparison:

1793

1927

1975

1984

2010

0

10

20

30

40

50

60

70

Recorded Floods at Nashville

Stage @ Nashville

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Cumberland River in NashvilleMay 2010 Flood Inundation

Downtown Pennington Bend/Opryland

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In The Beginning: The Nashville work began as a result of realized

shortcomings during the flood of May 2010.► 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

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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.

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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.

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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.

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Project Team

Nashville District

Metro NashvilleNational

Weather ServiceU.S. Geologic

Survey

Study Manager Team Leaders Local Staff Local Staff

5 EngineersStormwater

DivisionTechnicians

GIS SpecialistWatershed Advisors

AMEC

Interest and Support of Higher Organizational Levels

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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.

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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.

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Study Area

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Cumberland River Stages Referenced from the Nashville Gage (Datum, 368.1)Based on May 2010 Profiles

Depicts corresponding stages at other locations for referenced stages at the Nashville Gage.

Major

Moderate

Flood

Action

No Action

Increasing Understanding:

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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).

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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.

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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.

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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

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Nashville Flood PreparednessInundation Products

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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.

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HEC-RTS (Real-Time Simulation)

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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.

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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.

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If you have questions regarding USACE programs:

Contact:► Trena Bradshaw – District Outreach Coordinator

• Trena.D.Bradshaw@usace.army.mil• 615-736-7191

► Phyllis Kohl – Floodplain Management Services Program• Phyllis.Kohl@usace.army.mil• 615-736-5948

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Questions?