Year of Publication

2015

Season of Publication

Spring

Paper Type

Master's Thesis

College

College of Computing, Engineering & Construction

Degree Name

Master of Science in Civil Engineering (MSCE)

Department

Engineering

NACO controlled Corporate Body

University of North Florida. School of Engineering

First Advisor

Dr. Peter Bacopoulos

Second Advisor

Dr. Don Resio

Third Advisor

Research Director Nikki Dix

Department Chair

Dr. Murat Tiryakioglu

College Dean

Dr. Mark Tumeo

Abstract

Long term sustainability in salt marsh and mangroves is dependent on dominant species, such as Spartina alterniflora, to capture organic and inorganic sediment. The research analyzes that sustainability. This work demonstrates the prediction of hydrodynamics and biomass density of salt marsh to provide useful information for the planning and mitigation of sea-level rise impacts on marsh sustainability in the Guana Tolomato Matanzas National Estuarine Research Reserve (GTMNERR), Florida. An advanced circulation code was applied to simulate hydrodynamics (i.e., shallow water equations) in the GTMNERR. The model used a set of parameters and conditions based on the GTMNERR domain to predict tides for present-day conditions, which was validated using tidal data from eight monitoring stations within the GTMNERR. The hydrodynamic model results (i.e., MLW and MHW) were then coupled with a marsh equilibrium model to assess year-to-year biomass density for saltmarsh cordgrass (Spartina alterniflora). Vegetative data were obtained from the staff of the GTMNERR and organized for future work towards validation of biomass density predictions.

Simulations were then performed with sea-level rise scenarios of 0.13 m, 0.22 m and 0.51 m, which are standardized cases of mild, moderate, and extreme rise for the northeast coast of Florida. The simulation results show nonlinear increase of tidal datums for given sea-level rise, thus leading to nonlinear change in biomass productivity. The modeling tool has engineering implications in the way of assisting the planning of dredging spoils to be laid over the marsh to sustain existing marsh against rising sea levels. The modeling tool further provides information about marsh migration due to sea-level rise, whereby coastal planners can use this information to designate and preserve existing uplands/wetlands that will house salt marsh in the future, as the marshes will migrate into such upland/wetlands areas.

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