Mark R. Byrnes, Ph.D.


Areas of Expertise

  • Coastal and nearshore sediment transport
  • Coastal change assessment and sediment budgets
  • Processes affecting land loss in coastal and estuarine environments
  • Physical environmental impact assessments for coastal environments
  • Impact of coastal structures on shoreline response
  • GIS/mapping for coastal environments
  • Offshore sand resource evaluations


1988    Ph.D., Oceanography, Old Dominion University
1978    B.A., Earth Science, Millersville University

Dr. Byrnes has conducted and managed projects focused on coastal sedimentation processes and regional response of beaches, inlets, and estuaries to incident wave and current processes.  Example projects include Operational Sediment Budget for the Barrier Island Coast in South Louisiana; Determining Recent Subsidence Rates in Barataria Basin, Louisiana; Shoreline Compilation and Change Assessment for the Louisiana Barrier Island Comprehensive Monitoring Program; Sediment Budget Development and Coastal Processes Analyses Toward Implementation of the Barrier Island Restoration Program for Coastal Mississippi; Quantifying Settlement/Subsidence Associated with Barrier Beach Restoration in Coastal Louisiana; Damage Assessment Associated with Wetlands in the Northern Gulf of Mexico; Regional Sediment Management Assessment for the Northern Gulf of Mexico; Sediment Budget Evaluation for Mobile Bay; Channel Dredging Impacts on Shoreline Response at and Adjacent to Main Pass, Mobile Bay Entrance, Alabama; Environmental Survey of Identified Sand Resource Sites Offshore Alabama, Central East Florida, North Carolina, New Jersey, and New York; Study of the Environmental Impacts of Offshore Sand Mining in Massachusetts Bay.

Coastal Change Assessment and Sediment Budgets

Since 1984, Dr. Byrnes has contracted with Federal and State agencies to develop state-of-science methods for compiling and analyzing historical hydrographic and shoreline surveys for quantifying change in the coastal zone.  Detailed procedures were developed for compiling historical map data, where conversion from various cartographic parameters to a common coordinate system, map projection, ellipsoid, and datum is critical for accurately assessing change and associated potential measurement uncertainties.  These data represent the most basic and useful information for evaluating local and regional sediment transport dynamics and their influence on coastal evolution.  Applied Coastal personnel rely on hydrographic and shoreline surveys for basic and applied scientific research on sediment transport dynamics in the coastal zone. They also use shoreline and bathymetry data for developing sediment budgets, calibrating numerical models, and developing coastal structure design criteria.  Finally, these data are used for determining setback criteria for coastal construction.  Hydrographic surveys provide data to quantify channel shoaling rates and supply bathymetric data for developing regional circulation and sediment transport numerical modeling grids. Dr. Byrnes also has applied these techniques in wetland environments for evaluating causes of wetland change.

Processes Affecting Wetland Change

Wetland loss or gain is a function of natural processes such as sediment supply, waves and currents, subsidence and other geological controls, and sea-level change, as well as human activities in the coastal zone and within watersheds impacting coastal environments. Dr. Byrnes has conducted numerous projects focused on evaluating natural processes and human activities related to changes documented via shoreline mapping using maps, aerial imagery, and Lidar. Recent projects have addressed the magnitude of consolidation settlement associated with beach restoration along the outer coast of Louisiana, as well as determining subsidence rates using high-resolution GPS measurements associated with natural consolidation of sediment in a deltaic environment. These data are critical for understanding the evolution of wetlands because subsidence represents the dominant signal associated with relative sea-level rise in south Louisiana.

Impact of Coastal Structures on Shoreline Change

Dr. Byrnes has evaluated the impact of coastal structures on sediment transport dynamics and coastal evolution throughout the U.S.  He has been principal investigator on several projects assessing the influence of navigation and shore protection structures on beach response, including an evaluation of beach change to construction of 85 segmented breakwaters offshore southwestern Louisiana and an assessment of downdrift beach evolution in response to jetty construction at St. Marys Entrance, GA/FL; Grays Harbor and Columbia River, WA; Port Canaveral and Sebastian Inlet, FL; and Mattituck and Goldsmith Inlets, Southold, NY.  More recently, Dr. Byrnes has evaluated the impact of channel dredging on sand bypassing and littoral sediment transport processes for coastal Alabama and Mississippi, and for beaches on Long Island, NY. All projects relied on the application of GIS/mapping tools for accurate compilation and analysis of survey data sets.

Channel and Shoal Dynamics at Inlets

Since 1992, Dr. Byrnes has compiled and analyzed site-specific and regional bathymetric surveys to document the evolution of channels and shoals at entrances relative to navigation safety and environmental concerns. Most projects addressed shoal migration and sedimentation processes in navigation channels and environmental considerations associated with maintenance dredging activities.  Because sedimentation patterns and rates of change were determined by comparing sequential bathymetric and shoreline surveys, detailed procedures have been developed for compiling and analyzing data sets and associated potential measurement uncertainties.  Net sediment volume changes were quantified to develop inlet sediment budgets for predicting long-term system response to engineering activities.

Offshore Sand Resource Evaluations

Dr. Byrnes has conducted offshore sand resource evaluations for determining the sedimentary characteristics of deposits and associated potential environmental issues concerning sand mining on the Continental Shelf.  The geographic extent of these studies ranges from coastal Louisiana to offshore Massachusetts.  Dr. Byrnes’ primary interest is with the geological development of offshore shoals and the physical environmental effects of dredging activities in altering fluid and sediment transport patterns at potential borrow sites and along shorelines landward of resource areas.  Analyses rely on comparison of bathymetry and shoreline data sets and numerical modeling of waves and currents over variable bathymetry.  Analysis results supply information for policy decisions regarding potential dredging effects and for development of impact reports required under the National Environmental Policy Act in support of potential lease agreements.

Selected Publications

Byrnes, M.R., J.L. Berlinghoff, S.F. Griffee, A.R. Fallon, and D.M. Lee, 2018. Louisiana Barrier Island Comprehensive Monitoring Program (BICM): Phase 2 – Updated Shoreline Compilation and Change Assessment, 1880s to 2015. Prepared for Louisiana Coastal Protection and Restoration Authority (CPRA) by Applied Coastal Research and Engineering, Baton Rouge, LA and Mashpee, MA, 46 p. plus appendices.

Byrnes, M.R., L.D. Britsch, J.L. Berlinghoff, and R. Johnson, 2018. Determining Modern Subsidence Rates in Barataria Basin, Louisiana: Implications for Engineering and Design of Coastal Restoration Projects. Prepared for Louisiana Coastal Protection and Restoration Authority (CPRA) by Applied Coastal Research and Engineering, Baton Rouge, LA and Mashpee, MA, in cooperation with CDM Smith, Baton Rouge, LA, 67 p. including appendices.

Mendelssohn I.A., M.R. Byrnes, R.T. Kneib, and B.A. Vittor, 2017. Coastal Habitats of the Gulf of Mexico. In: C.H. Ward (ed), Habitats and Biota of the Gulf of Mexico: Before the Deepwater Horizon Oil Spill. Springer, New York, NY, p. 359-640.

Byrnes, M.R., C. Hedderman, M. Hasen, H. Roberts, S. Khalil, and S.G. Underwood, 2015. Differential sediment consolidation associated with barrier beach restoration: Caminada Headland, South Louisiana. In: P.Wang, J.D. Rosati, and J. Cheng (eds.), Proceedings Coastal Sediments 2015, World Scientific, Hackensack, NJ, 14 p.

Underwood, S.G., S. Khalil, M.R. Byrnes, G.D. Steyer, and R.C. Raynie, 2015. Operational considerations for implementing regional sediment management in the northern Gulf of Mexico. In: P.Wang, J.D. Rosati, and J. Cheng (eds.), Proceedings Coastal Sediments 2015, World Scientific, Hackensack, NJ, 12 p.

Byrnes, M.R., J.D. Rosati, S.F. Griffee, and J.L. Berlinghoff, 2013. Historical sediment transport pathways and quantities for determining an operational sediment budget: Mississippi Sound barrier islands. In: Brock, J.C., Barras, J.A., and Williams, S.J. (eds.), Understanding and Predicting Change in the Coastal Ecosystem of the Northern Gulf of Mexico, Journal of Coastal Research, Special Issue, No. 63, pp. 166-183.

Byrnes, M.R., J.L. Berlinghoff, and S.F. Griffee, 2013. Sediment Dynamics in Mobile Bay, Alabama: Development of an Operational Sediment Budget. Technical Report to the Mobile Bay National Estuary Program, Mobile, AL, 134 p.

Byrnes, M.R., J.D. Rosati, S.F. Griffee, and J.L. Berlinghoff, 2012. Littoral Sediment Budget for the Mississippi Sound Barrier Islands. Technical Report ERDC/CHL TR-12-9, U.S. Army Engineering Research and Development Center, Vicksburg, MS, 184 p.

Byrnes, M.R. and J.L. Berlinghoff, 2012. Gulf Regional Sediment Management Master Plan: Case study compilation. In: S.M. Khalil, L.E. Parson, and J.P. Waters (eds.), Technical Framework for the Gulf Regional Sediment Management Plan (GRSMMP), Journal of Coastal Research, Special Issue 60, pp. 72-124.

Byrnes, M.R., J.D. Rosati, and S.F. Griffee, 2011. Sediment Budget: Mississippi Sound Barrier Islands. In: P.Wang, J.D. Rosati, and T.M. Roberts (eds.), Coastal Sediments 2011, World Scientific, Hackensack, NJ, 2366-2379.

McBride, R. A., M.R. Byrnes, and L.D. Britsch, 2011. Subsidence-corrected elevations of paleoshorelines (chenier ridges) of the Mississippi River Chenier Plain, USA: implications for forcing mechanisms. In: P.Wang, J.D. Rosati, and T.M. Roberts (eds.), Coastal Sediments 2011, World Scientific, Hackensack, NJ, 176-187.

Byrnes, M.R., S.F. Griffee, and M.S. Osler, 2010.  Channel Dredging and Geomorphic Response at and Adjacent to Mobile Pass, Alabama. Technical Report ERDC/CHL TR-10-8, U.S. Army Engineer Research and Development Center, Vicksburg, MS, 309 p.

Byrnes, M.R. and R.A. McBride, 2009.  Coastal response to Hurricane Ike: Southwest Louisiana and southeast Texas.  Shore and Beach, 77(2): 37-48.

McBride, R.A., M.J. Taylor, and M.R. Byrnes, 2007.  Coastal morphodynamics and Chenier Plain evolution in southwestern Louisiana, USA: A geomorphic model.  Geomorphology, 88: 367-422.

Byrnes, M.R., S.F. Griffee, and H.R. Moritz, 2007.  Engineering activities influencing historical sediment transport pathways at the Columbia River Mouth, WA/OR.  In: N.C. Kraus and J.D. Rosati (editors), Coastal Sediments ’07, American Society of Civil Engineers, Reston, VA, pp. 1754-1767.