USING SPECIFICATION OF OVERBURDEN TO IMPROVE NUMERICAL LONGSHORE SEDIMENT TRANSPORT MODELING

Irene Watts,Gary Zarillo

doi:10.9753/icce.v36v.papers.10

Abstract

The Sebastian Inlet Florida Coastal Processes Model computes sediment transport pathways in the nearshore to support sediment management activities. Longshore sediment transport rates are computed by the model and compared with field data. The model is run with two alternative specifications of hard bottom to investigate the impact on computed transport rates. One alternative specifies known hard bottom outcrop locations and the second, a uniform one-meter overburden throughout the model domain. The uniform overburden specification improved longshore sediment transport rate computations throughout the model domain. The goal of this work is to improve upon nearshore sediment transport and morphology by addressing uncertainty in hard bottom locations and ephemeral coverage. This paper documents the modeling effort and the changes necessary to improve model performance in the nearshore.Recorded Presentation from the vICCE (YouTube Link): https://youtu.be/u1bNOca5qUo

Highlights

The Sebastian Inlet is one of the few connections between Florida’s Indian River Lagoon and the AtlanticOcean
These cross shore transects correspond to the annual surveys that are based on the Florida Department of Environmental Protection Coastal Range Monument Locations (FDEP, 2017) and generally span 300 m between each profiles. It is known from previous work and examination of the ebb shoal and downdrift attachment point, that the net movement of sediments is from North to South
This paper focuses on evaluating the performance of longshore sediment transport (LST) throughout the model as compared to measurements

Summary

Introduction

The Sebastian Inlet is one of the few connections between Florida’s Indian River Lagoon and the Atlantic. Sediments are routinely dredged from an interior sand trap located approximately 760 m from the inlet throat. A portion of the removed material is manually bypassed to the downdrift beaches on the south side of the inlet. The remained is stockpiled in an onsite dredged material management area (DMMA). The Sebastian Inlet District (District) is charged with managing the inlet resources and has employed the use of numerical models to assist in these management activities. Present work includes interest in refining longshore sediment transport calculations within the model

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