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

Sean.jpg

Areas of Expertise

  • Coastal processes analysis
  • Numerical modeling of estuarine hydrodynamics and water quality
  • Numerical modeling of wave and sediment transport processes
  • Evaluation and design of coastal structures and beach nourishment
  • Analysis of tidal inlet dynamics and sediment transport

Education

1999  M.S., Ocean Engineering, Texas A&M University
1993  B.S., Marine Engineering Technology, Maine Maritime Academy

Professional Registration

Professional Engineer (Civil), MA


Project Experience

Pleasant Bay Alliance, Muddy Creek, Pleasant Bay, Massachusetts

  • A hydrodynamic analysis of Muddy Creek was performed to determine the optimal width of the inlet channel under Route 28.  The existing stone structure that connects Muddy Creek to West Pleasant Bay has two 3-foot-wide culverts with a length of 100 feet.  This culvert structure restricts tidal exchange between the creek and the Bay, which has a direct effect on water quality in the creek.  Widening the channel under Route 28 would improve tidal flushing and likely lower nitrogen concentrations in the creek.  Sizing of the new inlet channel was based on maximum tidal velocities that would help maintain the channel, and prevent it from shoaling in with sediment.  The optimum configuration was determined to be a 24-foot wide crossing, which results in a sevenfold increase in the mean tide range.

Calcasieu Ship Channel and Pass. Lake Charles, Louisiana

  • Performed an analysis of sediment transport processes in Lake Calcasieu to support the DMMP for the Calcasieu Ship Channel and Pass. The numerical analysis evaluated physical processes governing circulation and sediment transport necessary to develop long-term solutions for dredged materials management. The modeling effort afforded a thorough understanding of the sediment sources and sinks, as well as the associated sediment transport pathways, while taking into account the complex circulation patterns that dominate the Lake Calcasieu estuarine system.

Coastal Processes Analysis for the South Coast of Chatham, Massachusetts

  • An analysis was performed of littoral sediment movement along the shoreline in the vicinity of two tidal creeks.  Mr. Kelley performed the analysis, utilizing two-dimensional hydrodynamic models of the two creeks that he developed during a previous study, and a separate shoreline model developed using the GENESIS computer code.  The models were used to assess impacts by inlet shoal on tidal flushing in each system, and asses the performance of a beach fill that he designed, and that was constructed in 2002.

New Crossing Hydrodynamic and Waves Analysis, Castle Harbor, Bermuda

  • Performed analyses to determine wave climate and baseline hydrodynamic conditions in Castle Harbor, Bermuda, in support of engineering design and environmental permitting for a new crossing between the nation’s commercial airport and the main island. Mr. Kelley was responsible for the collection and analysis of oceanographic data and development of a 2D hydrodynamic model. This model was used to evaluate different design alternatives for the crossing. Performed for the Bermuda Ministry of Works and Engineering.

Sailfish Point Property Owners Association, Hutchinson Island, Florida

  • A sediment transport analysis was performed along the shoreline of a private community in Martin County, FL.  A 7,200 reach of sandy beach was modeled using a one-line shoreline change model developed by Mr. Kelley.  Input to the shoreline model included wave conditions that were computed using the 2-D wave model SWAN.  This shoreline offered a unique engineering challenge due to an offshore reef that runs along to the entire length of the modeled beach.  This reef greatly impacts waves on the shore as well as sediment movement.  This model will be used to develop beach nourishment and possible structural options to address ongoing erosion issues along this shoreline.

Coastal Processes Analysis for the South Coast of Chatham, Massachusetts

  • An analysis was performed of littoral sediment movement along the shoreline in the vicinity of two tidal creeks.  Mr. Kelley performed the analysis, utilizing two-dimensional hydrodynamic models of the two creeks that he developed during a previous study, and a separate shoreline model developed using the GENESIS computer code.  The models were used to assess impacts by inlet shoal on tidal flushing in each system, and asses the performance of a beach fill that he designed, and that was constructed in 2002.

Sediment Transport Impacts by Offshore Borrow Sites, Jupiter Island, Florida

  • Mr. Kelley applied the method that he developed for determining the significance of borrow site induced changes to sediment transport potential along a shoreline at Jupiter Island, Florida. The results of the study indicate that remnants of nearshore borrow pits dredged between 1973 and 1987 still significantly affect sediment movement along the shoreline. Performed for Jupiter Island, Florida under contract with GBA.

Conceptual Coastal Engineering Alternatives for West Beach, New Bedford, MA

  • Engineering alternatives were evaluated to enhance the design life and storm survivability of an existing seawall at West Beach in New Bedford, MA.  The seawall protects the main sewer line to the treatment plant at the southern tip of the City.  The selected alternative needs to be protective of seagrass beds that exist in close proximity to the project shoreline.  A 2D wave model and a one-line shoreline model were created to determine the performance of different design options, including beach fill alone, beach fill with a toe berm, and beach fill with T-head groins to maintain the fill.  Based on a screening analysis of the modeled alternatives, the beach fill with T-head groins was determined to be the best option to provide protection of the critical upland infrastructure and also the offshore seagrass.

Town wide Coastal Processes Analysis, Town of Oak Bluff, Massachusetts

  • A comprehensive study of the entire eastern Nantucket Sound facing coast of the Town of Oak Bluffs on Martha’s Vineyard was performed in order to help quantify erosion rates and develop possible management solutions to help maintain public beach recreational resources.  Sediment transport potential was computed for entire Town shoreline, and the southern half of the 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 12,000 and 56,000 cubic yards were simulated for different sections of the coast.  These scenarios included options to reconfigure existing groins along the shoreline in order to improve their utility.

Winthrop Shores Reservation, Winthrop, Massachusetts

  • Mr. Kelley performed sediment transport analysis to determine the optimum beach nourishment design for Winthrop Shore Reservation, Winthrop, MA, a state park in the metropolitan Boston area.  The recently constructed 500,000 cubic yard nourishment is planned to provide shore protection and improve the recreational resources of the beach.  A model of the shoreline was developed and calibrated using historic shoreline change trends.

2-D Sediment Transport Analysis, Petit Bois Pass, Alabama

  • A two-dimensional sediment transport analysis was performed to determine possible impacts to a natural gas pipeline resulting from dredging a sand borrow site in Petit Bois Pass.  The pass lies between the east end of Dauphin Island and the west end of Petit Bois Island, near the Alabama and Mississippi border.  A suite of computer models was employed in this analysis, including the synoptic-scale hydrodynamic model ADCIRC and the local-scale coastal processes modeling package CMS.  The results of the analysis were used to provide guidance to the Mobile District of the US Army Corps of Engineers that would allow the maximum extraction from the planned borrow sites without endangering the pipeline.

Mason Inlet Hydrodynamic and Sediment Transport Analyses, New Hanover County, 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 the existing sediment pathways, and guided the development of a dredging plan to maintain the inlet and safe navigation in the ICWW.