Remote sensing as a tool to describe sediment bottom facies in coastal environments

A study of sediment bottom distribution was conducted on the nearshore area of Puerto Rico. The objective of this study is characterize the beach sand sources in the coastal environment using remote sensing. The qualitative and quantitative description of these sources played an important role in understanding the possible causes of shoreline changes. In this study, we identified and described sediment bottom types based on composition and textural characteristics. Thematic Mapper images (band 1) were used for data acquisition. The spectral band was used to analyze bathymetry, bottom types and sediment distribution. Two main bottom types were discriminated based on the radiance distribution. These are carbonate and mixed sands due to the similarities founded between the images and sediment maps. According to the data, higher radiance values were found from Isabela to Camuy, that could be related with the presence of lighter materials as carbonate sands. Lower radiance were measured at Mayaguez due to the presence of darker material as terrigenous sands. Discrimination of bottom marine facies is difficult to perform with TM due to the small ranges of radiances measured on the Puerto Rican nearhore waters.