Abstract: Effects of Variations in Wave Energy on Beach and Nearshore-Bar Morphology in Eastern Nicaragua

Edward H. Owens

Wave-energy levels at the shoreline are important in controlling variations in beach and nearshore-bar morphology on the eastern coast of Nicaragua. Incoming incident waves are modified differentially along the coast owing to a progressive decrease in shelf width from 200 km in the north to 25 km on the south. The resulting decrease in frictional attenuation toward the south and the subsequent increase in wave-energy levels at the shoreline are reflected clearly in the morphology of the littoral and nearshore-zone sediments. Narrow, straight beaches and linear bar systems characterize much of the northern section of this coast. Toward the south, as energy levels at the shoreline increase, the morphology becomes progressively more complex, with wide beaches characterized b rhythmic topography and nearshore crescentic bars and rip systems. The western Caribbean is an area of moderately high wave-energy levels, and the alongshore variability of wave height owing to a progressive change in shelf width is responsible for the different beach and nearshore morphology types. The abrupt variations within a small geographic area on the east coast of Nicaragua can be applied in a more general context to explain variations reported in other coastal environments and in stratigraphic research.

AAPG Search and Discovery Article #90961©1978 AAPG Annual Convention and Exhibition, Oklahoma City, Oklahoma