We are developing new routines within the COAWST model framework to represent coupled bio-physical processes in estuarine and coastal regions. These include routines for marsh vulnerability to waves, estuarine biogeochemistry, and feedbacks between aquatic vegetation and hydrodynamics.
Lateral erosion of marshes is partially dependent on the thrust of wind-waves on the vertical marsh face. Several studies have quantified this dependence: the wave characteristics, water depth, and marsh elevation are the controlling variables for the magnitude of the thrust. The COAWST model simulates these parameters, and is a valuable tool for calculating the variation of thrust under different environmental conditions. We have integrated a model routine that calculates time-varying thrust within COAWST, and exports it as a model state variable which can be visualized within our oceanographic portal.
Estuaries with elevated nitrogen loading are prone to eutrophication, whereby increased primary production by phytoplankton and macroalgae can create hypoxia and low light conditions and alter an otherwise healthy ecosystem. We are modifying biogeochemical routines in ROMS (within COAWST) to represent estuarine processes such as light attenuation, algal respiration, seagrass kinetics, and diel oxygen dynamics. The models can then be used to simulate reductions in nitrogen loading, shifts in seagrass distribution, and feedbacks between physical processes and ecosystem function.
Coastal protection and biophysical feedbacks require modeling of the interaction between aquatic vegetation (emergent marsh and submerged seagrass) and hydrodynamics (currents and waves). Properly accounting for three-dimensional modification of the flow field requires specifying the vertical variation of plant distribution, and then extracting momentum and dissipating turbulence in the water column. This exerts a drag on the fluid flow, attenuates waves, and reduces shear stress within vegetated canopies, allowing for positive feedbacks between vegetation, sediment deposition, and water clarity.
Below are publications associated with this project.
Sensitivity analysis of a coupled hydrodynamic-vegetation model using the effectively subsampled quadratures method
Development of a coupled wave-flow-vegetation interaction model
Spectral wave dissipation by submerged aquatic vegetation in a back-barrier estuary
Progress and challenges in coupled hydrodynamic-ecological estuarine modeling
Estimating time-dependent connectivity in marine systems
Modeling future scenarios of light attenuation and potential seagrass success in a eutrophic estuary
Effect of roughness formulation on the performance of a coupled wave, hydrodynamic, and sediment transport model
- Overview
We are developing new routines within the COAWST model framework to represent coupled bio-physical processes in estuarine and coastal regions. These include routines for marsh vulnerability to waves, estuarine biogeochemistry, and feedbacks between aquatic vegetation and hydrodynamics.
Lateral erosion of marshes is partially dependent on the thrust of wind-waves on the vertical marsh face. Several studies have quantified this dependence: the wave characteristics, water depth, and marsh elevation are the controlling variables for the magnitude of the thrust. The COAWST model simulates these parameters, and is a valuable tool for calculating the variation of thrust under different environmental conditions. We have integrated a model routine that calculates time-varying thrust within COAWST, and exports it as a model state variable which can be visualized within our oceanographic portal.
Estuaries with elevated nitrogen loading are prone to eutrophication, whereby increased primary production by phytoplankton and macroalgae can create hypoxia and low light conditions and alter an otherwise healthy ecosystem. We are modifying biogeochemical routines in ROMS (within COAWST) to represent estuarine processes such as light attenuation, algal respiration, seagrass kinetics, and diel oxygen dynamics. The models can then be used to simulate reductions in nitrogen loading, shifts in seagrass distribution, and feedbacks between physical processes and ecosystem function.
Coastal protection and biophysical feedbacks require modeling of the interaction between aquatic vegetation (emergent marsh and submerged seagrass) and hydrodynamics (currents and waves). Properly accounting for three-dimensional modification of the flow field requires specifying the vertical variation of plant distribution, and then extracting momentum and dissipating turbulence in the water column. This exerts a drag on the fluid flow, attenuates waves, and reduces shear stress within vegetated canopies, allowing for positive feedbacks between vegetation, sediment deposition, and water clarity.
- Publications
Below are publications associated with this project.
Sensitivity analysis of a coupled hydrodynamic-vegetation model using the effectively subsampled quadratures method
Coastal hydrodynamics can be greatly affected by the presence of submerged aquatic vegetation. The effect of vegetation has been incorporated into the Coupled-Ocean-Atmosphere-Wave-Sediment Transport (COAWST) Modeling System. The vegetation implementation includes the plant-induced three-dimensional drag, in-canopy wave-induced streaming, and the production of turbulent kinetic energy by the preseDevelopment of a coupled wave-flow-vegetation interaction model
Emergent and submerged vegetation can significantly affect coastal hydrodynamics. However, most deterministic numerical models do not take into account their influence on currents, waves, and turbulence. In this paper, we describe the implementation of a wave-flow-vegetation module into a Coupled-Ocean-Atmosphere-Wave-Sediment Transport (COAWST) modeling system that includes a flow model (ROMS) anSpectral wave dissipation by submerged aquatic vegetation in a back-barrier estuary
Submerged aquatic vegetation is generally thought to attenuate waves, but this interaction remains poorly characterized in shallow-water field settings with locally generated wind waves. Better quantification of wave–vegetation interaction can provide insight to morphodynamic changes in a variety of environments and also is relevant to the planning of nature-based coastal protection measures. TowaProgress and challenges in coupled hydrodynamic-ecological estuarine modeling
Numerical modeling has emerged over the last several decades as a widely accepted tool for investigations in environmental sciences. In estuarine research, hydrodynamic and ecological models have moved along parallel tracks with regard to complexity, refinement, computational power, and incorporation of uncertainty. Coupled hydrodynamic-ecological models have been used to assess ecosystem processeEstimating time-dependent connectivity in marine systems
Hydrodynamic connectivity describes the sources and destinations of water parcels within a domain over a given time. When combined with biological models, it can be a powerful concept to explain the patterns of constituent dispersal within marine ecosystems. However, providing connectivity metrics for a given domain is a three-dimensional problem: two dimensions in space to define the sources andModeling future scenarios of light attenuation and potential seagrass success in a eutrophic estuary
Estuarine eutrophication has led to numerous ecological changes, including loss of seagrass beds. One potential cause of these losses is a reduction in light availability due to increased attenuation by phytoplankton. Future sea level rise will also tend to reduce light penetration and modify seagrass habitat. In the present study, we integrate a spectral irradiance model into a biogeochemical modEffect of roughness formulation on the performance of a coupled wave, hydrodynamic, and sediment transport model
A variety of algorithms are available for parameterizing the hydrodynamic bottom roughness associated with grain size, saltation, bedforms, and wave–current interaction in coastal ocean models. These parameterizations give rise to spatially and temporally variable bottom-drag coefficients that ostensibly provide better representations of physical processes than uniform and constant coefficients. H