Gib Jones, P.E., CFM

June 1, 2016

GeoCoastal: CSHORE Modeling Tools

for Assessing Shoreline Response to

Coastal Hazards

• 1D cross-shore transect model

• Models near-shore processes simultaneously

• Sediment transport / erosion

• Wave setup

• Wave transformation and breaking

• Wave runup & overtopping

CSHORE Processes

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CSHORE

• USACE developed

model in Fortran

• No user interface –

text file input/output

• Needs good

bathymetry

• Time series input

from forecasted

storm data

• Models impacts to:

• Erosion

• Waves

• Runup

• Overtopping rate

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Dewberry’s GeoCoastal tools increases

productivity, level of detail, and quality in coastal

hazard and risk assessments.

• Automates Coastal Modeling

• Seamless Work Flow

• Facilitates inputs and analyzing outputs

• Consistent Modeling Result

• Easy-to-Use ArcGIS Interface

Benefits of incorporating CSHORE into

GeoCoastal Tools

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CSHORE Model – Runup Validation

All values are in feet Max Runup 2% 10% Significant Mean

TAW 14.21 11.04 10.05 7.92 4.95

RUNUP2.0 8.33 6.47 5.89 4.64 2.90

CSHORE 5.62 4.36 3.97 3.13 1.96

Measurements 6.65 5.17 4.71 3.71 2.32

Difference (TAW – Measured) 7.56 5.87 5.35 4.21 2.63

Difference (RUNUP2.0 – Measured) 1.68 1.30 1.18 0.93 0.58

Difference (CSHORE – Measured) -1.04 -0.81 -0.73 -0.58 -0.36

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Duck, NC

• Great Lakes – First implementation of CSHORE by FEMA

for flood studies

• New FEMA Coastal Guidelines Prepared

• Accurate nearshore bathymetry is important

• Nearshore bathymetry collected by USACE Detroit District in Lake

Erie

CSHORE in the Great Lakes

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Great Lake Coastal Studies

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436 Transects in Lake Erie

156 Transects in Lake Ontario

• Parameter Development• Seamless Topo/Bathy

• Boundary Conditions

• Sediment Size

GeoCoastal – CSHORE Inputs

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Regional 2D Modeling Input

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Time-series and maximum data extraction

• Regional 2D model doesn’t provide level of detail needed in

nearshore – need CSHORE for this

Great Lakes CSHORE Modeling

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• All nearshore processes

modeled simultaneously

• Erosion

• Wave setup

• Wave transformation/heights

• Runup

• Performed both response-

based and event-based

modeling

• Wave Runup and Erosion

• 155 storms for each Transect

• UnSteady State – Hydrograph inputs for storm surge and waves

Response-Based Modeling

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Figure D.3.5-5. Wave Runup Sketch

Barrier Slope Breaker Depth

Limit of Wave

Runup

Storm Still

Water Level

Source: FEMA, 2003

• Maximum Runup chosen from hundreds of time steps

(repeat 10,000+ times)

Runup Results

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• Utilizes Matlab stats package to analyze Runup and JPM

for waves• Response-based Runup GPD (Generalized Pareto Distribution)

• JPM (Joint-Probability Method) for water level/wave analysis

• Combined probability of water levels and waves at the shoreline

Statistical Analysis

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• Event-based (1% annual chance) modeling • Five scenarios/events modeled using WHAFIS

• Utilizes Previously-developed GeoCoastal capabilities

• Inputs come from CSHORE:• Wave conditions at shoreline (unsteady state hydrographs)

• Eroded profile

Event-based Modeling

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GeoCoastal Tools

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• Can be run step-by-step

or straight through

• Progress Screen• Monitor progress• View which files are being used• Identify where progress stops

• Study generates huge amounts of data

• More than 3600 files and 160 graphs (>60GB) per

Transect

• 6 databases and more than 200,000 files (>4TB) per

County

• All parameters, processes and results organized

in databases

GeoCoastal File Management

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• Ability to answer critical EM-related questions:

• How much erosion will occur?

• When will overtopping occur?

• Potential breaching areas?

• When will roads be impassable?

• When do homeowners need to be out?

• Potential EM/planning products

• Severity of beach erosion areas

• Potential overtopping and breaching areas

• Wave damage potential areas

• Scenarios with probabilities

CSHORE for Forecasting

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Forecasting & Analytics

• GeoCoastal - CSHORE Benefits

• Increases efficiency

• Shortens modeling duration

• Easily change parameters, run scenarios

• Stores input, output in organized fashion

• Helps minimize human error

• Customizable for other models and processes

• Applications beyond FEMA flood studies

In Summary

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For more information Contact:

Jeff Gangai: jgangai@dewberry.com (703-849-0251)

Gib Jones: gjones@dewberry.com (703-849-0130)

GeoCoastal - CSHORE

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