7/28/2019 Integrated GIS-based Low and High fidelity flood simulations

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(a) (b) (c) (d)

Katrina (Aug 23-31, 2005) wind pressure plots. (a) WRF simulation starting from Aug 26, 00 A.M., (b) WRF simulation starting from Aug 27, 12 P.M. (c) Actual, usingPlanetary Boundary Layer (PBL) from Aug 24 to Aug 31, (d) Track path

(e) (f) (g) (h)

ADCIRC simulation high water elevation for Katrina with wind speed and pressure obtained from (e) WRF simulation, starting from Aug 27, 00 A.M., (f) PlanetaryBoundary Layer (PBL), starting from Aug 28, 00 A.M. (g) PBL, starting from 27, 00 A.M., (h) Actual / PBL, starting from Aug 23, 6 P.M.

(i) (j) (k) (l)

Simulated Katrina flood by CaMEL Overland model. (i) Validation with 1-D benchmark result [4], (j) High Water Mark (HWM) from simulation, (k) HWM observationlocations superimposed on simulated result, (l) Comparison of observed and simulated HWM. (WRF rain data was not used in the current study)

Materials and Methods

Introduction

Integrated GIS-based Low and High fidelity flood simulationsSudha.Yerramilli, Muhammad Akbar, Reena Patel and Shahrouz Aliabadi

Northrop Grumman Center for HPC , Jackson State University, Jackson, Mississippi 39217

Results Conclusions

Literature Cited

Acknowledgements

For further Information

This pro ject was funded through the Southeast Reg ion ResearchInitiative program from the Department of Homeland Security,ScienceandTechnology Directorate,Infrastructure andGeophysical Division.

Contact Information: Dr. Shahrouz Aliabadi, saliabadi@jsums.edu. Moreinformation on this and related projects can be obtained at

www.ngc.jsums.edu

The low fidelity flood simulation is done using Hydrologic Engineering Centers River Analysis System (HECRAS), a U.S Army corps1-D Model [5] for the coastal counties of Mississippi.

Hazard identification and vulnerability assessment is visually represented by overlaying HEC-RAS output withthe thematic layers of the key facilities in the coastal counties using ArcGIS.

An efficient flood risk management requires the knowledge of spatial and temporal distribution of floods.

Knowledge of spatial distribution of flood and its possible damage potentials are very crucial for risk mapping

and decision support systems. Therefore, appropriate methods, models and technologies that can simulate and

visualize flood characteristics are essential and can be considered as the corner stones of the mitigation efforts.

Our high fidelity flood simulation research proposes an integrated tool for multi-scale storm surge and overland

flow (flood) forecast, as well as evaluation of t he flood damage on coastal infrastructure including transportation

systems in the Mississippi coast.

Based on the latest meteorological data, wind speed, pressure, rain, ocean water surge can be predicted.

Several hurricane forecasting models are executed in sequence to obtain those information. The ocean water

surge is then used to predict the overland water flow in the coastal area.

The results from the models are fed into Geographical Information Systems (GIS) for visualization, analysis and

decision-making.

Flood initiated from the rain, river overflow, and dam-break is another component of the project.

Our low fidelity flood simulation proposes flood initiated from the rain, river overflow, and dam-break. By

generating information like inundated areas, water depths, flow direction etc, this study can help the decision

making agencies in implementing non-structural solutions such as controlling development in flood-prone areas,

planning new dams and managing appropriate land use practices that minimize possible flood damages.

A complete and integrated high fidelity hurricane flood simulation requires several software to be executed in

sequence:

Open source code Weather Research and Forecasting (WRF) [1] provides wind speed, pressure, rain, etc information

based on the latest meteorological data. WRF is a parallel model, which is designed to serve both operational

forecasting and atmospheric research needs. It is suitable for a broad spectrum of applications across scales ranging

from meters to thousands of kilometers.

Wind speed and pressure from WRF is used in open source code ADvanced CIRCulation (ADCIRC) [2] to calculate the

ocean water elevation. ADCIRC is a highly developed computer program for solving the equations of motion for a

moving fluid on a rotating earth.

The time dependent shoreline water surge data from ADCIRC and rain data from WRF are used as the Dirichlet

boundary input in our CaMEL Overland code [3] to predict flooding in the coastal region. The rain data predicted from

WRF is used as the source term in the model.

The graphical presentation shows the integration of the whole simulation process:

WRF

ADCIRCCaMELOverland

GIS

Shoreline Water Elevation

Visualization

GIS

The CaMEL Overland has been benchmarked, as shown in Figure (i).

Overland simulation depends on the ADCIRC result along the coast line . Figure (j) shows the simulated flooded regions. In general, simulated result and observeddata compare well, shown in Figures (k) and (l).

Over prediction by our model in some locations may have caused by

over prediction by ADCIRC in the coast line.

diffusive overland model we have used without any ground and structural friction effects

ADCIRC requires wind speed and pressure from WRF. The results depend on the accuracy of WRF simulation. The WRF result used in Figure (e) did not have latestmeteorological data. It shows water surge is occurring somewhere in east compared to the actual location shown in Figure (h).

ADCIRC simulation has to be done for several days around the hurricane period, typically 5-7 days, to get reasonably good results. Longer simulation period capturesboth short and long wave lengths. Figure (g) is somewhat better than Figure (f) because of longer simulation period. Comparison should be made with Figure (h).

ADCIRC also needs tidal information, which can be interpolated from tidal database.

Landfall location makes a huge difference. Hurricane striking Louisiana coast may cause huge water surge because of converging funnel effect of the land.

WRF simulation results heavily depend on the latest meteorological data. Hurricane may take unexpected turns, which only the latest meteorological data may reflect.Therefore, WRF is recommended to run for not more than 2 to 3 days in advance.

Figure (a) falsely shows the hurricane is striking t he ground near Mississippi-Alabama coast. It is mainly because WRF could not predict the path accurately basedon the meteorological data available on Aug 26, 00 A.M. Actual hurricane path is shown in Figure (c) and (d).

Figure (b) predicts the hurricane well. In actual hurricane event, WRF should be run more frequently to predict the latest path, strength, and landfall location ofhurricane.

An integrated tool for high fidelity multi-scale storm surge and

overland flow forecast, as well as evaluation of the flood damage oncoastal infrastructure including transportation systems in theMississippi coast has been proposed.

The hurricane wind speed, pressure, and rain information is

simulated by WRF using the latest meteorological data. Accuracy ofWRF depends on the accuracy of meteorological data available.

To simulate correct water elevation by ADCIRC, latest WRF result,

including the correct landfall location, is needed.

Hurricane landfall location is important. A hurricane striking

Louisiana coast may cause devastating water surge because of theconverging funnel effect of the land.

ADCIRC simulation of several days prior to hurricane landfall isneeded to capture all short and long waves. Typically 5-7 days ofsimulation is good.

Overland results heavily depends on the ADCIRC shoreline watersurge. On the other hand, since the code is diffusive in nature, a

safety factor should be applied.

In an actual hurricane event frequent simulation of WRF, ADCIRC,and CaMEL Overland in sequence is needed for dynamic forecast.

The results from these above mentioned models are fed intoGeographical Information Systems (GIS) for visualization, analysisand decision-making.

The combination of Arc GIS and HEC RAS 1-D low fidelity floodsimulation model indicate the capability of simulating flood events

and spatially depicting the degree of exposure or vulnerability of theregion towards a hazard event in terms of inundation extent anddepth grids.

Information tools developed using the combination of thesetechnologies can generate invaluable information and assist the

decision making authorities to make informed choices towardsmitigating the catastrophic effects of flooding disaster.

1. Michalakes, J., J. Dudhia, D. Gill, J. Klemp and W. Skamarock:

Design of a next-generation regional weather research and forecastmodel : Towards Teracomputing, World Scientific, River Edge, NewJersey, 1998, pp. 117-124.

2. Westerink, J. J., Luettich, R. A., Blain, C. A., & Scheffner, N. W.,ADCIRC: An advanced three-dimensional circulation model forshelves, coasts and estuaries. Report 2: Users Manual f or ADCIRC-

2DDI. Technical Report DRP-94, U.S. Army Corps of Engineers.

3. Akbar, M.K., Aliabadi, S., Wan, T., and Patel, R. "Overland Flow

Modeling of Mississippi Coastal Region Using Finite ElementMethod", Accepted, 19th AIAA Computational Fluid DynamicsConference, June 22-25, 2009, San Antonio, TX.

4. Beinhorn, M., Kolditz, O., Overland flow theory and implementation.GeoSys - Preprint. Tubingen March 2005. Version 2005.1.1. ZAGPublisher

5. U.S.Army Corps of Engineers.http://www.hec.usace.army.mil/software/hec-ras/

Digital Elevation Model (DEM) MARIS

100 Year Stream flow data, River/stream

data, Land Cover-USGS.

Inventory data on the property, utilities,

infrastructure HAZUS(MH)

The preprocessing of the geospatial data was done using HEC Geo RAS.

The preprocessed data is then exported to HEC-RAS

The May 1995 Southern Mississippi flood, which is considered as significanthydrological event (a 100-year rainfall event), is simulated by using USGS

stream flow data available for Harrison and Hancock counties.

A steady flow simulation was performed on HEC RAS model and the output

was exported to HEC Geo RAS f or post processing to delineate the floodinundation areas

A visual presentation of flood water in combination with thematic maps (keyfacilities) is developed using Arc GIS

(a) HEC RAS flood simulation for the 100-year rainfall event in May 1995

Collection ofData

Prepare Thematiclayers in Arc GIS

Obtain USGS Streamflow data for 100-year

flood event

Preprocess Geospatialdata using HEC GeoRAS

Simulate Flood usingHEC RAS for the 100-

year flood EventOverlay Flood

inundationoutput with

thematic layers

Disseminate information using Arc IMS

Post process HECRASOutput using HEC

GeoRAS

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-95 -90 -85 -80 -75 -70

Hurricane Katrina23-31August

Hurricane

TropicalStorm

TropicalDep.

Extratropical

Subtr. Storm

Subtr. Dep.

00UTCPos/Date

12UTCPosition

Low/ Wave

PPP Min. press (mb)

25

24

31

30

29

2827

26

902mb

920mb

984mb

928mb

mailto:saliabadi@jsums.edumailto:saliabadi@jsums.edu