Landslides and floods zonation using geomorphological analyses in a dynamic basin of Costa Rica

Despite of the geomorphological diversity of Central America and Costa Rica, there are few detailed geomorphological studies in the region. A 1:25,000 geomorphological analyses of the Upper General River Basin (UGRB) located in the southeast in Costa Rica is presented, based on the interpretation of aerial photographs and field geomorphological mapping. First, a morphometric analysis was performed to calculate and analyze seven variables that were merged in order to produce the flood and landslides susceptibility maps. Second, a total of 43 types of landforms divided genetically into endogenic (tectonic), and exogenic (fluvial, gravitational, and glacial) features are mapped for an area of 1560 km2. Finally, a geomorphological hazard map with the zonation of the different susceptibility levels of landslides and floods were performed. This cartography is important in terms of geomorphological evolution, disaster risk reduction as well as for land use planning for approximately 40,000 inhabitants. The presented methodology can also be applied in other developing countries for different purposes such as landscape evolution, morphogenetic detailed maps, disaster risk reduction, and land use planning.