Geomorphological evolution between 1948 and 2012 of the Terraba-Sierpe delta, Costa Rica

The Terraba-Sierpe delta is located at the geographic coordinates 8 degrees 47 '' North Latitude and 83 degrees 38 '' West Longitude at the southeast of Costa Rica. It is a delta system formed by the sediments carried from the largest river basin in the country (Terraba), and the Sierpe River. These rivers have modeled a meandriform drainage pattern where it dominates the mangrove vegetation. This fluviomarine complex has had major morphology modifications due to the alteration in sedimentation rates by climate variability and land use changes in the middle and upper basins of the Terraba and Sierpe rivers. For the reconstruction of the geomorphological evolution of the six delta mouths: Coronado, Brava, Chiquita, Zacate, Guarumal and Sierpe; it was used a methodology based on photointerpretation and analysis of four aerial images of the years 1948, 1972, 1992 and 2012. In addition, were analyzed the texture and grain sand distribution from the three types of coastal bars of the delta: submarine, insular, and littoral. The importance of this work lies in the study of morphological changes in a tropical delta threatened by environmental impacts and changes in the climate over 64 years.