GIS-based land suitability assessment for check dam site location, using topography and drainage information: a case study from Morocco

Check dams are used as effective structures for harvesting surface water and controlling soil erosion, runoff and flooding at a watershed scale. However, a great challenge remains in identifying the best suitable sites for the location of check dams. This study aimed to develop a GIS-based map helpful to guide the selection of suitable sites for check dams within Khenifra province area, Morocco. The approach adopted uses a multi-criteria decision analysis (MCDA) integrated into geographic information system (GIS). DEM-derived datasets are used to develop the suitability model, including slope (S), drainage density (DD), stream order (SO), stream power index (SPI), topographic wetness index (TWI), sediment transport index (STI), terrain roughness index (TRI) and topographic position index (TPI). The accuracy of the approach is assessed by using the receiver operating characteristic curve (ROC = 0.833) and the area under the curve (AUC = 0.875). The resulting map reveals sites in high and very high suitability classes along 51.5% of the total stream length in drainage area and shows a fine concordance with depression areas prone to inundation in the study area. Also, a high accuracy is reached with depressions exceeding 5 m depth. Selected examples of suitable sites have storage capacities between about 200,000 m 3 and more than 500,000 m 3 . Thus, the land suitability mapping is an inexpensive and easy-to-apply method that supports the decision makers for sustainable development.