Sam Bentley
Professor and Billy and Ann Harrison Chair Louisiana State University
Biography
Areas of Expertise
Research Focus
Sedimentary Dynamics & Deltaic Systems
Dr. Bentley’s research focuses on sedimentary dynamics of coastal and deltaic systems, particularly the Mississippi River delta and adjacent continental shelf. He combines sediment coring, radiometric dating, and numerical sediment-budget modeling to quantify land loss, guide coastal restoration, and forecast delta resilience under sea-level rise.
Education
SUNY Stony Brook
Ph.D.
Coastal Geological Oceanography
1998
University of Georgia
M.S.
Geology
1992
University of Georgia
B.A.
Theater, Geology (minor)
1985
Accomplishments
Fellow, American Association for the Advancement of Science
2022
James Lee Wilson Award , Society for Sedimentary Geology,
2003
LSU Tiger Athletic Foundation Award for Excellence in Teaching
2003
Media Appearances
WATCH: Tipping Point – The Mighty Mississippi | A PBS News Special
PBS tv
2025-07-15
The Mississippi River, North America’s largest river system, is under threat.
Air and water pollution, downstream flooding and coastal land loss are among the environmental pressures that are putting the health and future of the waterway — and the communities that depend on it — at risk.
Scientists face ecological and economic hurdles to save Mississippi River Delta
PBS tv
2025-08-08
The iconic Mississippi River Delta is of enormous importance to the country, especially near the Gulf Coast. It's an economic engine and a key wildlife habitat. But it's shrinking considerably due to a variety of factors, including engineering done decades ago. Science Correspondent Miles O'Brien looks at those problems and efforts to prevent further loss.
Louisiana's Bird's Foot Delta is disappearing. This new grant will help plan for its future.
NOLA online
2023-11-01
The new Mississippi River Delta Transition Initiative, or MissDelta, will include the development of new, state-of-the-art computer models to help researchers determine how the lower delta, from mile 44 on the river’s east bank to its mouth, will change over the next 100 years, said Tulane professor Mead Allison and LSU professor Samuel Bentley, co-leaders of the consortium.
Louisiana Coastal Loss Drives 'Environmental Disenfranchisement'
AAPG Explorer online
2018-09-07
"Conditions are dire for much of the coastal region of the Mississippi River Delta and our children’s children will see a coastal landscape that we might not recognize.”
That’s the warning of Sam Bentley, associate dean for research at Louisiana State University College of Science, as well as the Billy and Ann Harrison chair in sedimentary geology at the school.
Articles
Temporal Scales of Mass Wasting Sedimentation across the Mississippi River Delta Front Delineated by 210Pb/137Cs Geochronology
Journal of Marine Science and Engineering2024
The Mississippi River Delta Front (MRDF) is a subaqueous apron of rapidly deposited and weakly consolidated sediment extending from the subaerial portions of the Birdsfoot Delta of the Mississippi River, long characterized by mass-wasting sediment transport. Four (4) depositional environments dominate regionally (an undisturbed topset apron, mudflow gully, mudflow lobe, and prodelta), centering around mudflow distribution initiated by a variety of factors (hurricanes, storms, and fluid pressure). To better understand the spatiotemporal scales of the events as well as the controlling processes, eight cores (5.8–8.0 m long) taken offshore from the South Pass (SP) and the Southwest Pass (SWP) were analyzed for gamma density, grain size, sediment fabric (X-radiography), and geochronology (210Pb/137Cs radionuclides). Previous work has focused on the deposition of individual passes and has been restricted to
Sedimentary Processes and Instability on the Mississippi River Delta Front near the Shipwreck of the SS Virginia
Water2024
Sediment cores were collected from a mudflow lobe (80 m water depth) offshore of the Mississippi River’s Southwest Pass in 2017 to better understand the sedimentology near the lobe entraining the SS Virginia shipwreck (sunk by a German U-boat in 1942) and surrounding Mississippi River delta front. Core analyses included 210 Pb/137 Cs geochronology, granulometry, and X-radiography. Sediment accumulation rates (SAR) calculated from excess 210 Pb activity in multicores are 0.22–0.29 cm/y at seabed depths less than 20 cm and 0.29–0.51 cm/y at depths greater than 20 cm. Accumulation rates for 137 Cs have been~ 0.15 to~ 0.37 cm/y since 1954 and 1963, respectively. Sediment accumulation rates from 210 Pb, 137 Cs geochronology and indicators of relative sedimentation and bioturbation from X-radiographs suggest that rates of sediment accumulation near the Virginia have declined since the mid-20th century.
Morphodynamic modeling of Fourleague Bay in Mississippi River Delta: Sediment fluxes across river-estuary-wetland boundaries
Coastal Engineering2023
To mitigate land losses in the Mississippi River Delta, sediment diversions are being employed to enable the flow of river water and sediments into wetlands experiencing degradation. A two-dimensional coupled flow-wave Delft3D model was used in this study to explore the hydrodynamics and sediment transport in Fourleague Bay (FLB), Louisiana, USA, which has been considered an analog site for studying the efficiency of sediment diversion projects. In-situ measurements of sediment accretion and hydrodynamic characteristics from 2015 to 2016 were utilized to calibrate and validate the morphodynamic model. The validated model was then applied to quantify sediment transport in FLB and surrounding marshes between May 2015 and May 2016. The results show that more sediment could be deposited to the surrounding marshes with high river discharges and strong winds.
Capture Timescale of an Uncontrolled Mississippi–Atchafalaya Bifurcation with Future Lower River Strategy Implications
Journal of Coastal Research2023
The most recent and currently active delta lobe of the Mississippi River (MR) is the Atchafalaya–Wax Lake lobe, which was initiated approximately 400 years ago as a result of MR stream capture by the Atchafalaya River (AR). This capture process accelerated in the early to mid-1900s but further development was prevented by construction and operation of the Old River Control Structure (ORCS) complex in 1962. Because the initial research to warrant the construction of the ORCS was undertaken nearly 70 years ago, this study revisits the basis of the resulting predictions and evaluates how both branches could evolve moving forward both with and without ORCS controls. This study uses the Delft3D software suite to retest the capture hypothesis by accounting for complex hydrodynamic interactions from the MR/AR bifurcation to the Gulf of Mexico. A 150-year model duration was used to adequately characterize bifurcation evolution, stream capture life cycle, and long-term river management concerns.
Affiliations
- Council of Colleges of Arts & Sciences
- American Association for the Advancement of Science
- American Geophysical Union
- Society for Sedimentary Geology
Event Appearances
Sediment transport and geomorphologic response in multiple dredge pits near Ship Shoal of coastal Louisiana
2018 | American Geophysical Union Fall Meeting Washington, DC
Sediment Accumulation and Bioturbation in a tropical-carbonate mangrove forest on a Pacific atoll: Ouvéa, New Caledonia
2018 | American Geophysical Union Fall Meeting Washington, DC
DELTA SEES: Sustainability of Deltaic Coastlines
2018 | American Geophysical Union Fall Meeting Washington, DC
Research Grants
Digital Twin: Building next-generation visualization talent and technology for NASA manufacturing
NASA
2022-2024
Challenge Subaward - H2theFuture: A Transformative Energy Cluster Strategy to Decarbonize the South Louisiana Industrial Corridor
Greater New Orleans Development Foundation
2021-2022
Louisiana Sediment Management Plan (LASMP): Central Coast Regional Sediment Inventory and Sediment Budget Program
The Water Institute of the Gulf
2022-2024
Media
