Coastal Processes Analysis for Vilano Beach, St. Johns County, FL

Taylor Engineering, Inc.Hande Caliskan, M.Sc.

Christopher Bender , Ph.D., P.E., D.CEMichael Krecic, P.E.

U.S. Army Corps of Engineers, Jacksonville District, FLJason Engle, P.E.

OVERVIEW• Project Description

o Purposeo Project Site

• Study Approacho GenCade SMS Interfaceo Data

• Calibration/Verificationo Procedureo Results

• Sensitivity Analysis• Summary and Results

PROJECT DESCRIPTION

PURPOSE

• USACE Jacksonville District is conducting a Hurricane and Storm Damage Reduction Study

• The GENESIS Model will provide erosion rates for beach nourishment alternatives

PROJECT SITE

STUDY APPROACH

Regional Contour

Initial Shoreline

GENESIS Grid

Wave Stations

R-64

R-69

R-74

R-79

R-84

R-89

R-94

R-99

R-104

R-109

R-114

R-119

DATA

• Florida Coastal Forcing Project (FCFP) Wave Data for Saint Johns County, FL

• FCFP Data at every 5th nearshore station

• FDEP Historical MHW and Beach Profile Data

CALIBRATION

R-84Small MHW

Shoreline Change

Large Volume Change

R-84

R-114

Small MHW Shoreline Change

Large Volume Change

-125

-100

-75

-50

-25

0

25

50

75

100

0 5000 10000 15000 20000 25000 30000 35000 40000 45000 50000 55000 60000 65000

Distance from R-63 (ft)

Sh

orel

ine

Pos

itio

n C

han

ge (

ft)

Measured Shoreline Change

Calibrated Model Shoreline Change

Shoreline Change Calculated fromMeasured Volume Change

Project Area

SENSITIVITY ANALYSES

Parameter Range Model Value

Time Step 0.25 – 2.00 hr 0.25 hr

D50 0.1 – 0.5 mm 0.2 mm

Berm Height 7 – 9 ft 9 ft

Depth of Closure 20 and 25 ft 20 ft

K1 0.5 – 0.75 0.75

K2 0.25 – 0.4 0.4

Model Parameters

SUMMARY AND RESULTS

• The shoreline change modeling component of the St. Johns County, Florida Hurricane and Storm Damage Reduction Feasibility Study developed and calibrated a GENESIS model for the study area (R-84 in South Ponte Vedra Beach southward to R-121 in Vilano Beach north of St. Augustine Inlet).

• The study applied the GENESIS model within the GenCade regional sediment management tool developed by the USACE ERDC.

• The calibrated and verified GENESIS model results agree well with measured beach volume changes during the calibration period (July 1986 to January 1999).

• The model produces reasonable agreement with measured volume changes during the verification period (January 1999 to August 2007)

• Additional model simulations documented the calibrated and verified GENESIS model sensitivity to selected model parameters.

QUESTIONS???