Submerged aquatic vegetation (SAV) plays an important role in riverine and estuarine processes. By attenuating flow and modulating flow turbulence, SAV promotes sediment stability, provides food and shelter for numerous important species and improves water quality. SAV thus forms a critical link between physical habitat and biological communities. Flexible SAV blades interact with the flow field and with each other in complex, but ecologically significant ways. For example, above a critical flow velocity threshold, continuous SAV canopy motion (monami) occurs, which is associated with the abundance of attached algae on SAV. To date, our understanding of how SAV structure affects flow attenuation and mass transport is still limited, and physical interactions among vegetation blades are not included explicitly in most observational efforts, theoretical analyses or modeling studies. This project will develop an integrated modeling framework supported by field observations and experiments. The new model will support engineers and natural resources managers tasked with developing legally mandated minimum flow requirements for springs restoration. The project supports two PhD students, who will receive interdisciplinary training in hydrodynamic modeling, aquatic ecology, and data analysis. A hands-on outreach activity and K-12 lesson plan will be developed using a portable racetrack flume at the UF Coastal Lab.
The primary goal of this study is to quantify the influence of vegetation structural properties and blade-to-blade interactions on hydrodynamics and characterize the collective behavior of flexible vegetation canopies under different flow conditions. The study develops a structural solver that integrates soft-body dynamics into a finite element model to investigate the deformation of vegetation blades and interactions between multiple blades. The structural model will be coupled with a computational fluid dynamics model to study flow over interacting submerged flexible vegetation. Field observations in multiple Florida springs will be carried out, in which velocimeters and video cameras will collect hydrodynamics and vegetation canopy data (such as effective vegetation heights and monami characteristics). The model will be validated with observational data, and then used to identify different flow regimes based on vegetation structural properties and flow conditions. This project will develop an improved parameterization of the effects of SAV on hydrodynamics on river reach-scale using observation data and model results, which can be implemented in large-scale modeling framework to study the effects of SAV on key ecosystem processes, such as sediment transport and algae growth dynamics.
This award reflects NSF's statutory mission and has been deemed worthy of support through evaluation using the Foundation's intellectual merit and broader impacts review criteria.
