Beach morphological dynamics at Cocos Bay (Manzanilla), Trinidad

Abstract

Manzanilla beach in Cocos Bay, Trinidad is a barrier beach that protects the freshwater Nariva Swamp from the marine environment of the Atlantic. Manzanilla beach is a very dynamic system owing to the open bay morphology, and exposure to the Atlantic Ocean. This study evaluated the spatial and temporal morphological and sedimentological characteristics, alongside hydrodynamic conditions operating on the beach. It investigates the beach's response to tidal cycles diurnally, from spring to neap tide, and seasonally. Data from nine sites during the period December 2005 to September 2007 are analyzed. Coastal parameters such as beach profiles, littoral data and sediment samples were obtained using standard geomorphological techniques. Beach volumetric changes that occurred over the tidal cycles are also quantified. Results indicate that wave height and wave energy were good predictors of beach change. The study showed that erosion was linked to rising tide and accretion to falling tide diurnally. Erosion occurred during spring tide conditions and accretion dominated during neap tides. Seasonally more erosion occurred in the winter period (dry season) and beach changes in the summer period (wet season) were controlled by the formation and migration of bars. © Atlantic Geology 2013.