Donald and Martha Harleman Professor
Margaret MacVicar Fellow
Fellow, American Geophysical Union
ASCE, Hunter Rouse Hydraulic Engineering Award
Chi Epsilon Honor Member
Distinguished Engineering Alumni Award – Bucknell University
18th Harold Jan Schoemaker Award
NSF Career Award
School of Engineering Bose Award for Excellence in Teaching
Samual M. Seegal Prize, MIT – for inspiring student in pursuing excellence
Earll Murman Award for Excellence in Undergraduate Advising
IAHR M. Salim Yalin Lifetime Achievement Award
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In natural streams, vegetation may grow in spatially heterogeneous patterns of individual patches. Different flow regimes develop near the vegetation, depending on the evolution of wake structure between the patches. The flow regime affects the ecological, biological, morphological processes in aquatic system. My current research focuses on the growth of turbulent flow structures in the gap between patches and on how the wakes interact to develop flow structure over a wide range of scales. Specifically, I am conducting a series of laboratory experiments with submerged flexible vegetation (Rotala indica), in which I will vary the gap between patches. The experiments will identify the patch spatial density (gap spacing) for which there is a transition from heterogeneous near-bed flow, moving around individual patches, to flow structure defined by a vertical shear layer, with uniformly low velocity near the bed. The result of this study will provide a model to predict real-world fluvial processes such as morphodynamic evolution, flow resistance, and habitat in channels with submerged flexible vegetation patches.
NSERC Postdoctoral Fellow
Vegetation plays an important role in the natural systems, including rivers and coats. Vegetation impacts the fluid mechanics as well as sediment transport. In my research at MIT, I am interested in investigating the interaction between fluid mechanics and channel bed sediment (i.e., scour and deposition) numerically, under different vegetation scenarios. This will have significant practical engineering applications in both river and costal engineering designs, especially in nature-based solutions (NBS) designs. I am using computational fluid dynamics (CFD) tools to predict the behavior of vegetated flows.
Visiting Postdoc from University of Twente, Netherlands
Salt marshes are vegetated coastal wetlands with benefits for coastal protection, biodiversity, and carbon sequestration. Their complex interaction between currents, waves, fine sediments, and vegetation creates a dynamic shoreline that is resilient or erosive. Resilient salt marshes have sufficient sediment deposition to withstand erosion and may even expand, whereas erosive salt marshes are shrinking and provide fewer ecosystem services. My goal is to understand how salt marsh vegetation affects sediment deposition using experiments in the Nepf Lab wave-current flume. Vegetation can reduce current and wave velocities, which may enhance deposition. However, the interaction between currents, waves and vegetation also generates turbulence, which contributes to sediment resuspension. My experiments will define different regimes for sediment deposition under conditions with combined waves and currents. The results will provide insight on sediment deposition patterns on salt marshes, and, consequently, salt marsh resilience.
I am examining sediment transport. In my undergraduate studies, I had field experiences observing suspended cohesive sediment transport on tidal flats. In particular, my trips to coastal saltmarshes in Jiangsu, China, have set me thinking about how marsh plant species like Spartina alterniflora and Spartina anglica will interact with local sediment transport and morphodynamics, and how researchers can integrate vegetation-induced turbulence and drag into sediment transport models. To study these problems, I have started my graduate career in the Nepf Lab in Fall 2018.
Research Affiliate, Nepf Environmental Fluid Mechanics Laboratory, MIT
Senior Research Assistant, Laboratory of Hydraulics, Hydrology and Glaciology (VAW), ETH Zurich
Numerous rivers have been confined and are eco-morphologically impaired, resulting in an increased demand for river restoration projects. Wood placements are a common and inexpensive measure for river restoration. To plan and evaluate river restoration projects including wood accumulations, it is important to understand the interactions between flow, wood, and sediment. Using physical modeling, my project aims to quantify flow and morphological structures associated with different wood accumulation setups. The results will be used to develop design recommendations for wood accumulations.
I grew up on the East Coast and have spent many summers in the Great Lakes region. It’s easy to take for granted the roles that vegetation play in nature, and view plants as ugly weeds to clear instead of species to protect. Seagrasses provide important habitat, carbon sinks, and other ecological functions, but are threatened by overdevelopment, pollution, and climate change. Long meadows of seagrass have been shown to attenuate currents and attenuate wave energy, but the dynamics of wave damping in the presence of currents are not as well understood. In addition, the morphological characteristics of plants vary widely in scope and in their relative contributions to vegetation-induced drag in oscillatory flow. I plan to investigate these areas to improve our understanding of the complex but ubiquitous interactions between flow and vegetation. Improved models of flow interactions with vegetation can help predict how storms and currents will affect vulnerable meadows, and help design infrastructure and living shorelines to protect coastal areas.
Coastal marshes serve as a natural source of coastal protection. To determine the makeup and size of coastal marshes, drones with RGB and NIR capability will be used to both quantify (biomass distribution + vegetation height) and qualify (species) coastal marshes. My goal is to determine the effectiveness of coastal marshes as a source of coastal protection by calculating, and identifying trends linking vegetation makeup and size to effectiveness, the wave attenuation given various marsh sizes.
Nature has evolved to know best how to stay resilient against natural forces. My research examines the science of how marshes can be placed in front of seawalls to attenuate wave amplitude and wave energy to reduce over topping and erosion. This is studied using wave dissipation models based on the physics of wave-vegetation hydrodynamic interactions. Hybrid coastal defense strategies not only offers important ecosystem services to combat climate change challenges, but also potentially deliver the same level of coastal protection more economically. Therefore, I will also conduct cost-benefit analysis on combined marshes and seawall infrastructures to examine whether societies would benefit economically from implementing nature based coastal protection and live more harmoniously with the natural environment.
My research is concerned with the design and implementation of nature-based coastal adaptation in urban settings. Despite increased interest in the incorporation of natural ecosystems in coastal engineering projects, there are still many gaps in our understanding of how these ecosystems perform hydrodynamically under extreme weather conditions and future climate scenarios. Using a combination of physical and numerical experiments, I will investigate wave attenuation and resilience of hybrid coastal defense strategies under various flow conditions, particularly the ability of oyster beds to reduce wave-driven flooding and overtopping during storms. I will then use a coastal-scale hydrodynamic model to explore implementation in an urban study area, with the goal of providing coastal communities with the tools to design physically and ecologically resilient waterfronts. Watch me on the “Ask MIT” Podcast.
For profiles of lab alumni, visit the alumni page.