Characterizing Seagrass Effects on Hydrodynamics of Waves and Currents
Through Field Measurements and Computational Modelling
Abstract
Low-lying coastal and estuarine areas are among the most populated
regions globally, have high economic significance, and are increasingly
threatened by climate change, sea level rise, nuisance flooding, and
extreme storms. Nature-based coastal protections are sustainable and
sea-level resilient alternatives compared to traditional solutions such
as dikes and seawalls. Submerged aquatic vegetation (SAV) or seagrasses
can provide coastal flood and erosion protection by attenuating storm
wave and current energy and stabilizing seabed sediments. However, more
research is needed to understand the interactions between flow, SAVs,
and sediments. These dynamic interactions affect flow at different
scales and seagrass productivity. In this study, we present field
measurements of current and wave evolution over a seagrass meadow in
South Bay, Virginia. The high vertical resolution measurements show how
currents change from above-canopy to in-canopy waters. Wave measurements
indicate the dissipation and frequency modulation over the canopy. The
results are compared with hydrodynamic simulations using a two-way
coupled flow-vegetation interaction model that simulates nonlinear
current and wave evolution as well as dynamics of highly flexible
vegetation.