Research Interests

My research program examines various aspects of erosion and sedimentation primarily in fluvial systems through the use of experimentation, theory, field studies, and numerical modeling. The overall goals of the research are to quantify flow and sediment transport processes using an interdisciplinary approach and to determine the impact of these processes on river form and function, water quality and ecology, landscape evolution, and watershed infrastructure and integrity. This work is fundamentally important because sediment is one of the leading causes of water quality impairment nationwide, and soil erosion is the leading cause of soil degradation worldwide. Excessive sedimentation also reduces the performance of flood-control reservoirs and increases risks to flooding within river corridors. Below is a brief description of these activities, divided into four categories.

Sediment Transport Processes in Streams and Rivers
For uniform and steady flows in rivers, the entrainment and transport of sediment of various sizes, shapes, and densities depend on the gravitational and frictional forces keeping the grains in place, the time- and space-varying fluid forces acting to move and suspend the particles, and the development of bedforms that further modulate boundary layer characteristics. Work to date, utilizing state-of-the-art instrumentation, has focused on the following topics.
Phase Doppler anemometer described in Bennett et al. (1998; flow is right to left)
RIpple bedforms described in Venditti et al. (2005; flow is left to right)
 Low-relief bedwave (bedload sheet) described in Kuhnle et al. (2006)

Some representative papers recently published include:

Erosion Processes on Hillslopes and Upland Areas
Rill and gully development in upland concentrated flows occur as a discrete soil erosion process intimately related to the occurrence and upstream migration of headcuts. These areas of intense, localized erosion often are the primary cause of soil loss and the dominant source of sediment yield from agricultural landscapes. The formation, growth, and migration of headcuts has been linked to the concentration of overland flow, rill and gully erosion and development, erosion of bedrock channels, the initiation of drainage systems and landscape evolution, and the response of landscapes to land use change and extreme hydrologic events. Work to date, utilizing specially-designed experimental facilities and state-of-the-art instrumentation, has focused on the following topics.

Actively migrating headcut described in Bennett et al. (2000; flow is from left to right)
Velocity magnitude within a headcut plunge pool described in Bennett and Alonso (2006; flow is from left to right)

Some representative papers recently published include:

Sedimentation Issues in Flood-control Reservoirs
There are more than 75,000 dams in the continental U.S., and these structures provide opportunities for navigation, hydroelectric power, irrigation, flood reduction, and hazard protection. Yet these dams divide or segment watersheds with respect to water, sediment, nutrient transfer, and ecosystem dynamics. Because reservoirs effectively trap sediment, these impoundments have proven to be important environmental “archives” of changes in water quality parameters, land use, and sediment yield. The overall goals of the current research program are to assess the sediment impounded by these dams in terms of the structure’s ability to regulate floodwaters and the potential hazard these sediments may pose to the environment. Work to date, utilizing various techniques, has focused on the following topics.
Stratigraphic intrepretation of impounded sediment described in Bennett and Dunbar (2003)
Vibracore system on Grenada Lake, MS described in Bennett et al. (2005)

Some representative papers recently published include:

Riparian Vegetation and Fluvial Geomorphology
Because of increased popularity of vegetation in stream restoration and streambank stabilization programs, there is renewed interest in examining the interactions between river flow, riparian vegetation, and large woody debris. There are instances, however, when bank instability causes excessive recruitment of large woody debris, which can effectively choke downstream river corridors as witnessed along the Yalobusha River, MS. The overall goals of the current research program are to assess the interactions between open channel flow and rigid vegetation and to determine how river flow processes and forms are modulated such vegetation. Work to date, utilizing various techniques and facilities, has focused on the following topics.
Turbulent flow around emergent, rigid vegetation using particle image velocimetry described in Bennett (2004; flow is from bottom to top)
Large woody debris accumulation along the Yalobusha River, MS (looking upstream)

Some representative papers recently published include:


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