In: Proc. 29th Coastal Engineering Conference, World Scientific Press, 2005, pp. 2232-2242.
APPLICATION OF A PREDICTIVE CHANNEL SHOALING AND
MIGRATION MODEL, M3D, TO ST MARYS ENTRANCE,
FLORIDA
CHRISTOPHER W. REED
URS Corporation, 3676 Hartsfield Rd.
Tallahassee, FL 32303 USA
HIMANGSHU DAS
URS Corporation, 3676 Hartsfield Rd.
Tallahassee, FL 32303 USA
ALAN W. NIEDORODA
URS Corporation, 3676 Hartsfield Rd.
Tallahassee, FL 32303 USA
The growing need to deepen, widen, and reorient navigation channels through coastal
inlets to accommodate deep-draft vessels calls for improved predictive tools. A
numerical model, M3D, which represents marine sediment dynamics with sufficient
resolution to analyze and predict patterns of shoaling and scour, has been developed and
applied to simulate channel survey data collected at St. Marys Entrance, FL-GA, USA,
with good results. The observed systematic decrease in shoaling rate with distance
offshore is correctly simulated and can be explained by the dependence of bottom stresses
on water depth and the ambient grain size.
1.
Introduction
The U.S. Army Corps of Engineers (USACE) maintains channels through more
than 150 federally authorized coastal inlets. Many of these channels will be
deepened in the future or modified to improve channel reliability (amount of
time safe navigation can occur) in accommodation of larger vessels (Hess
2001). Predictive tools are required to estimate operation and maintenance
dredging for channels to be modified, as well as to connect the sediment-
transport processes between the navigation project and the adjacent beaches.
Few engineering predictive tools are available for conducting studies to
understand and predict channel shoaling or infilling, channel migration, scour
near jetties, and morphologic response.
Currents, waves, sediment transport, and morphology form a coupled
dynamic system with multiple levels of nonlinear feedback between the
components. Waves and currents interact and cause the entrainment of bottom
sediment. Currents distort the propagation of waves, and waves change the
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