Sean W. Kelley, P.E., M.S., B.S.

• Hydrodynamic and Sediment Transport Modeling for the Calcasieu Ship Channel and Pass, LA

Mr. Kelley completed an analysis of hydrodynamic and sediment transport process for Lake Calcasieu, Louisiana, in support of the DMMP for the Calcasieu Ship Channel and Pass using MIKE21. Numerical modeling was used to analyze physical processes governing circulation and sediment transport to develop long-term solutions for dredged material management. Modeling afforded a thorough understanding of sediment sources and sinks, as well as associated sediment transport pathways relative to typical tidal flow and high flow freshwater events, while taking into account the complex circulation patterns that dominate the Lake Calcasieu estuarine system with the dynamic and varying influences of the Gulf of Mexico, Intracoastal Waterway, and freshwater inflow. 

• Evaluation of Offshore Sand Borrow Site Excavation on Littoral Sand Transport, Ship Island, MS

Mr. Kelly led the engineering team assessing the impacts to coastal processes associated with offshore sand mining of 8.5 MCY along the Ship Island. The analysis considering spatial (longshore) and temporal aspects of the local wave climate on littoral sand transport variability and shoreline response for pre- and post- dredging conditions. A SWAN wave model was used to simulate how wave fields were modified by bathymetry under pre- and post-dredging conditions and then used to determine sediment transport potential along the entire shoreline. Alongshore variations in the computed gradient in sand transport were then evaluated to determine significance envelopes to evaluate long-term alterations to the littoral transport system and recommend modifications to the dredging templates to prevent the development of erosion hotspots along the Island.

• Channel Dredging and Geomorphic Response at and adjacent to Mobile Pass, Mobile, AL 

Mr. Kelley performed an assessment of USACE dredging practices and the influence on shoreline erosion of along the Barrier Islands offshore of the coast of Alabama. The analysis involved the evaluation of shoal and shoreline response relative to storm and normal forces and dredging in the outer bar channel. The project evaluated historical shoreline and bathymetry datasets, utilized numerical modeling of waves, hydrodynamics and sediment transport to validate the changes evaluated using the long-term change data to determine the extent to which beach erosion along Dauphin Island could be attributed to channel construction and maintenance dredging operations.  

• Massachusetts Department of Ecological Restoration, Parkers River, Yarmouth, MA

A series of hydrodynamic design simulations were made using a two-dimensional hydrodynamic model Mr. Kelley developed of Parkers River estuarine system. The purpose of this analysis was to select optimum channel dimension for a new Route 28 (state highway) bridge, and then to determine how the new channel would affect the highest tide elevations during typical astronomical tides and how the redesigned channel would affect storm conditions relative to flood risk concerns. The engineering evaluation also evaluated the lowest astronomical tide elevations to address concerns related to anadromous fish migration and influence of tidal velocity magnitudes.  

• Storm Surge and Wave Analysis, Rockefeller Wildlife Refuge, Cameron Parish, LA 

Analyses provided information needed for coastal engineering design and the assessment of erosion control alternatives. Mr. Kelley completed a numerical analysis of nearshore wave climate and storm surge was conducted to quantify the influence of storm waves and surge on the shoreline response. Modeled nearshore waves and surge were used to compute maximum shear stress values along transects perpendicular to the shoreline. The influence of regional shoals on local wave processes was evaluated using semi-quantitative methods, which provided a conservative estimate of wave sheltering provided by the shoals without requiring extensive wave refraction/diffraction models. 

• Chatham South Shore Sediment Budget, Town of Chatham, MA 

A comprehensive study of the entire southern coast of the Town of Chatham on Nantucket Sound was performed in order to help quantify erosion rates and develop possible sediment management solutions to help maintain public beach recreational resources.  The entire Town shoreline was modeled using a one-line shoreline change model developed by Mr. Kelley.  Inputs to the model included average wave conditions computed using the 2-D wave model SWAN.  Beach fill scenarios in the range between 10,000 and 50,000 cubic yards were simulated for different sections of the coast.

• Mason Inlet Hydrodynamic & Sediment Transport Analyses, New Hanover, NC.  

A two-dimensional (depth-averaged) hydrodynamic and sediment transport modeling analysis was performed for the Mason Inlet system (which includes 1,300 acres of salt marsh). A previous project had re-established a historic creek channel between the Atlantic Intracoastal Waterway (ICWW) and Mason Inlet.  Subsequent to the channel dredging, unexpected shoaling occurred in the system channels and in the ICWW. The modeling analysis determined and quantified the existing sediment pathways and guided the development of a dredging plan to maintain the inlet and provide safe navigation in the ICWW.

• Massachusetts DCR, Point Allerton Seawall, Hull, Massachusetts.  

An analysis of design wave conditions, revetment stone size, and structure elevation was performed for the Point Allerton Seawall Boulevard revetment and Point Allerton seawall, both located at the northern tip of Hull, Massachusetts.  Mr. Kelley’s work included a determination of extremal wave conditions, and maximum overtopping rates during storms. The analysis guided the recommended options for repairing the wall and improving its performance.