Date of Award
1-2026
Document Type
Dissertation
Degree Name
Doctor of Philosophy (PhD)
College/School
College of Science and Mathematics
Department/Program
Earth and Environmental Studies
Thesis Sponsor/Dissertation Chair/Project Chair
Greg Pope
Committee Member
Stefanie Brachfeld
Committee Member
Josh Galster
Committee Member
Jesse Kolodin
Abstract
Beaches are dynamic landforms that provide critical ecosystem services, including coastal protection, habitat, and recreation. On developed coastlines, the natural sedimentological and geomorphic processes governing these systems are increasingly overprinted by human intervention, primarily through beach nourishment. While essential for erosion mitigation, the long-term, integrated impacts of nourishment on sediment characteristics, beach morphology, and shoreline evolution remain poorly quantified. This dissertation provides a complete synthesis of these impacts through four analytical studies (Chapters 2–5) focused on the intensively managed coastlines of Cape May and Wildwood, New Jersey. Chapter 1 integrates the methodologies, findings, and implications of the core research chapters. Chapter 2 establishes the modern cross-shore sedimentological baseline, revealing that decades of nourishment have fundamentally coarsened and texturally altered the beaches compared to pre-nourishment conditions. Wildwood's sediments are homogeneous and fine, indicative of a low-energy, nourishment-dominated system, while Cape May exhibits complex, seasonally variable textures reflecting its higher-energy setting. Chapter 3 quantifies the resulting beach morphodynamic state, demonstrating that nourishment grain size is a primary control on beach form. A predictive model was developed, showing that selecting specific sediment sizes can strategically engineer a beach towards a desired dissipative, reflective or intermediate state. Moving beyond physical properties, Chapter 4 investigates sediment provenance and composition, finding that the modern beach sand is overwhelmingly sourced from the inner continental shelf via nourishment. This has reset the geological baseline, replacing the historical, mineralogically diverse "Hornblende Zone" with an ultra-mature, quartz-dominated assemblage, with no significant evidence of anthropogenic chemical contamination. Finally, Chapter 5 presents a multi-decadal synthesis, correlating shoreline change with environmental forcings and nourishment history. The results show that nourishment has become the dominant geological forcing agent, effectively decoupling the shoreline from natural hydrodynamic drivers. Cape May has achieved "Managed Equilibrium" through high-volume nourishment, while Wildwood remains in "Persistent Transition," with nourishment sand fueling extreme erosion in the north and accretion in the central to south. Collectively, this work demonstrates that beach nourishment is not a simple volumetric exercise but a profound geological intervention that redefines the physical and compositional character of the coast. The findings mandate a paradigm shift in coastal management from reactive sediment placement to proactive, geomorphologically informed design, where the strategic selection of sand grain size is critical for achieving long-term physical resilience, ecological function, and societal benefit.
File Format
Recommended Citation
Balasuriya, Aluthgama Divomi Hemali, "Anthropogenic and Natural Influences on the Dynamic Evolution of Managed Coasts: Sedimentology, Geochemistry, and Morphology of Cape May and Wildwood Beaches" (2026). Theses, Dissertations and Culminating Projects. 1630.
https://digitalcommons.montclair.edu/etd/1630