Efectos de las estructuras construidas por el hombre sobre tramos de linea de costa al norte, oeste y sur de Puerto Rico (Spanish text)

The building of man-made structures may cause unexpected effects in the coastal system. This thesis quantified shoreline changes associated with different kinds of shoreline structures located in sectors of the north, west and south coasts of Puerto Rico. Aerial photographs taken between 1936 and 1998 and Geographical Positions System (GPS) transects were used to measure changes. Each of the photographs was converted to digital format and with the support of a Geographical Information Systems (GIS) program was set to a common coordinate system. The coastline was traced using the wet/dry sand line. When the position of the coastline was obtained for different years, a comparison and quantification of the rate of change was made with positions before and after the structure was built. This procedure showed whether changes in the beach were caused by the structures. (Abstract shortened by UMI.)...