Statistical approach of factors controlling drainage network patterns in arid areas. Application to the Eastern Anti Atlas (Morocco)

Several studies have revealed that the complexity in the distribution of drainage network patterns is not random and controlled by major parameters, variable in space but also throughout geological time. Drainage networks in the Eastern Anti-Atlas of Morocco consist of complex spatial arrangements with various types of patterns, such as trellis, angular, dendritic and parallel. The objective was to distinguish, quantify and rank the relationship that may exist between the different drainage networks patterns, geology and geomorphology. A total of 230 basins were extracted from the ASTER-GDEM Elevation Data (USGS), which were assigned 16 parameters reflecting their topography, morphometry, slope and geology. The statistical treatment of the dataset (16 variables x 230 observations) was carried out through principal component analysis (PCA), linear discriminant analysis (LDA) and agglomerative hierarchical clustering (AHC), in order to investigate the complexity of drainage network patterns and their distribution. The PCA showed that the topographical, slope and geological parameters, i.e. primarily the parameter associated with structural control, best explains the variation in the type of the drainage pattern. The LDA made it possible to distinguish between the four types of drainage patterns with a success rate of 90%, using 3 discriminant functions that were better correlated with geological and slope parameters. LDA and AHC statistical treatments show confusion between the parallel, trellis and angular patterns, on the one hand, due to similar factors responsible for their formation, and on the other because of transitions phenomenon from one drainage pattern to another over time or space. Such possible drainage network shifting may be explained by the geological events that have occurred in the Eastern Anti Atlas from Lower Mesozoic to the Quaternary. [Display omitted] •230 basins were analyzed by 16 parameters reflecting topography, morphometry, and geology.•Structural control, lithological homogeneity and relief variation control the variation of drainage patterns.•Four types of drainage patterns were distinguished, with a success rate of 90%, using 3 discriminant functions.•Statistical treatments show confusion and similarity between parallel, trellis and angular patterns.