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to Assess the Effects of Marsh Vegetation, New Jersey |
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Numerical
Modeling
Wave
and Current Sediment Transport
Modeling
Environmental
Permitting
Flood
Hazard Assessment
Restoration
Hydraulic DesignValidation
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Woods
Hole Group, Inc. conducted a diagnostic study to evaluate offsite flooding
in an idealized marsh basin by employing a state-of-the-art hydrodynamic
model capable of simulating flooding and drying events due to the rise
and fall of the tide. The large idealized basin was composed of tidal
creeks and marsh types, from a muddy substrate to a heavily vegetated marsh.
The results of the model were utilized to examine set-up, flooding extent,
and hydroperiod. In a shallow marsh environment, vegetation growth
is a primary factor in flow resistance, and can be expressed in terms of
a Manning’s n friction coefficient in the hydrodynamic model. The
impact of various vegetation scenarios (i.e., changes in vegetation type,
chances in vegetative coverages, etc.) was evaluated through an assessment
of fluctuations in set-up, flooding extent, and hydroperiod.
RMA-2,
a two-dimensional, depth-integrated finite element model, was used to simulate
and explore the hydrodynamics in this idealized creek and marsh system.
This model solves the shallow water wave equations, and yields three quantities
of interest: water level, and two horizontal velocity components.
By changing the marsh friction from one simulation to next, the impact
of vegetative effects on the hydrodynamics of the system was evaluated.
The
figure above illustrates the maximum flooding extent in the idealized marsh
basin with Manning's n equal to 0.025 in the creek channels and ocean,
and 0.075 on the marsh plain. As high tide enters the system, the
water floods into the creeks, and then onto the marsh plain.
Flooding extent is determined by a number of factors, including tidal range,
marsh topography, and frictional effects. As the tide lowers, water
funnels back into the creek, and exits through the inlets.
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Woods Hole Group offers customized
Capabilities for each client and assignment. |
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Woods
Hole Group has experienced
Scientists and Engineers involved in solving environmental problems. |
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Woods
Hole Group provides consulting
services and products to Clients throughout the world. |
| Coastal Sciences, Engineering & Planning |  |
| Aquatic Environmental Assessment |  |
| Oceanography & Measurement Systems |  |
| For more information please call or e-mail the
:
Robert P. Hamilton Jr. at 508-495-6229 bhamilton@whgrp.com |
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Woods
Hole Group
Marine Environmental Solutions 81 Technology Park Drive, East Falmouth, MA 02536 Tel: 508-540-8080 Fax:508-540-1001 © 2002-2003, Woods Hole Group, Inc. |