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Effects of proposed navigation channel improvements on sediment transport in Mobile Harbor, Alabama

Open-File Report 2018-1123

Prepared in cooperation with the U.S. Army Corps of Engineers
By:
https://doi.org/10.3133/ofr20181123

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Abstract

A Delft3D model was developed to evaluate the potential effects of proposed navigation
channel deepening and widening in Mobile Harbor, Alabama. The model performance was
assessed through comparisons of modeled and observed data of water levels, velocities, and bed
level changes; the model captured hydrodynamic and sediment transport patterns in the study
area with skill. The validated model was used to simulate changes in sediment transport for existing
conditions and with the proposed modifications to the navigational channel (with-project),
with and without accounting for 0.5 meter (m) of sea level rise (SLR). Each scenario was simulated
for 1 year with a wave climatology representative of the year 2010 as well as for 10 years
with a longer-term wave climatology spanning from 1988 to 2016. Bed level differences for the
existing and with-project 2010 simulations were minimal, ranging from −0.11 to 0.11 m offshore
of Pelican Island and −0.81 to 0.22 m offshore of the Fort Morgan Peninsula. For the simulations
accounting for 0.5 m of SLR, differences in bed levels from −0.20 to 0.32 m near Pelican
Island and −0.38 to 0.34 m offshore of the Fort Morgan Peninsula. The proposed modifications
reduced the channel shoaling volume by 4.77 and 8.09 percent for the 2010 simulations without
and with 0.5 m of SLR, respectively. For the 10-year simulations, bed level differences for the
existing and with-project simulations ranged from −3.17 to 3.94 m for the simulation without
SLR and −1.92 to 1.47 m for the simulation with 0.5 m of SLR. The with-project condition reduced
the entrance channel shoaling volume by 5.54 percent for the simulation without SLR and
14.98 percent for the simulation with 0.5 m of SLR.

Suggested Citation

Passeri, D.L., Long, J.W., Jenkins, R.L., and Thompson, D.M., 2018, Effects of proposed navigation channel improvements on sediment transport in Mobile Harbor, Alabama: U.S. Geological Survey Open-File Report 2018–1123, 22 p., https://doi.org/10.3133/ofr20181123.

ISSN: 2331-1258 (online)

Study Area

Table of Contents

  • Abstract
  • Introduction
  • Modeling Approach
  • Modeling Results
  • Discussion
  • Summary and Conclusions
  • References Cited

Additional publication details

Publication type:
Report
Publication Subtype:
USGS Numbered Series
Title:
Effects of proposed navigation channel improvements on sediment transport in Mobile Harbor, Alabama
Series title:
Open-File Report
Series number:
2018-1123
DOI:
10.3133/ofr20181123
Year Published:
2018
Language:
English
Publisher:
U.S. Geological Survey
Publisher location:
Reston, VA
Contributing office(s):
St. Petersburg Coastal and Marine Science Center
Description:
Report: vii, 22 p.
Country:
United States
State:
Alabama
Other Geospatial:
Mobile Bay
Online Only (Y/N):
Y
Additional Online Files (Y/N):
N