Mead Allison
Professor and Chair, Department of River-Coastal Science and Engineering
Areas of Expertise
Biography
Hydrodynamics and sediment dynamics of modern environments including lowland river, deltaic, wetland, estuarine, and continental shelf settings. Impact of humans and climate change on coastal systems. Examination of the late Holocene sediment record in coastal settings. Use of particle-reactive radiotracers for sediment geochronology. Processes of sedimentary strata formation.
Education
State University of New York, Stony Brook
East Carolina University
College of William & Mary
Articles
Suspension of bed-material sand over lateral bars in the lower Mississippi River, Southeastern Louisiana
2013
Understanding specific pathways for sand transport in the lower reaches of large rivers, particularly the Mississippi, is the key to addressing multiple significant geologic problems and for environmental restoration efforts. Field studies were performed in the Mississippi River 75-100 km upstream of the Gulf of Mexico outlet in April 2010 (water discharge: 23,000 m³ s⁻¹), May 2010 (18,500-20,500 m³ s⁻¹), and March 2011 (27,000 m³ s⁻¹) to examine sediment transport phenomena in the river channel.
Historical reconstruction of mangrove expansion in the Gulf of Mexico: linking climate change with carbon sequestration in coastal wetlands
2013
There has been considerable interest in a recently recognized and important sink in the global carbon pool, commonly referred to as “blue carbon”. The major goal of this study was to determine the historical reconstruction of mangrove expansion (Avicennia germinans) into salt marshes (Spartina alterniflora) and its effects on carbon sequestration and soil chemistry in wetland soils of the northwestern Gulf of Mexico. We used bulk stable isotopic, chemical biomarker analyses, and aerial imagery analysis to identify changes in OC wetland sources, and radiotracers (137Cs and 210Pb) for chronology. Soil cores were collected at two sites at Port Aransas, Texas (USA), Harbor Island and Mud Island.
River discharge influences on particulate organic carbon age structure in the Mississippi/Atchafalaya River system
2013
Applying ramped pyrolysis radiocarbon analysis to suspended river sediments, we generate radiocarbon (14C) age spectra for particulate organic carbon (POC) from the lower Mississippi‐Atchafalaya River system (MARS) to better understand a major river system's role in carbon transport. Ramped pyrolysis 14C analysis generates age distributions of bulk carbon based on thermochemical stability of different organic components. Our results indicate higher proportions of older material in the POC during higher discharge.
Mississippi River channel response to the Bonnet Carre Spillway opening in the 2011 flood and its implications for the design and operation of river diversions
2013
The large Mississippi River flood in 2011 was notable in the lowermost Louisiana, USA reach for requiring operation of several flood control structures to reduce stress on artificial levees: the largest diversion went through the gated Bonnet Carré Spillway, which was opened for 42 days in May and June. The removal of approximately 20% of the total flood discharge from the river provided an opportunity to examine the impact of large water diversion on the sediment transport capacity of large rivers.
Bottom turbulence on the muddy Atchafalaya Shelf, Louisiana, USA
2010
Wave, current, and sediment observations collected in approximately 5 m depth on the muddy Atchafalaya clinoform, LA, USA, are used to study the interaction between near-bed wave-induced turbulent flows and suspended sediment characteristics in a muddy environment.
Media Appearances
Could Mississippi River change course? New research raises question, but Corps says plan working
In 1900, around 5 percent of the water from the Red River and the upper Mississippi was going down the Atchafalaya; by the 1950s, the Atchafalaya was collecting about 30 percent, said Tulane University professor Mead Allison, director of physical processes and sediment systems at the Water Institute in Baton Rouge.
