Groundwater potential zones mapping by applying GIS, remote sensing and multi-criteria decision analysis in the Ghiss basin, northern Morocco

Abstract

The Ghiss watershed, located in a Mediterranean semi-arid area, is currently experiencing a prolonged drought. The scarcity of potable surface water has driven the population and the government to intensify the exploration of groundwater resources. Conventional methods used for groundwater exploration are generally expensive, time-consuming and are limited in space. Therefore, we suggest with the present study the application of geospatial techniques (Geographical Information Systems (GIS) and Remote Sensing) and Multi-criteria decision analysis as a non-conventional and more accessible method of groundwater exploration in the Ghiss basin. Accordingly, eleven factors of high importance concerning the delineation of groundwater potential zones were weighted depending on their relative importance using the Analytical Hierarchy Process's (AHP) pairwise comparison matrix. The GIS-based analysis of multiple thematic layers (drainage density, lineament density, roughness, lithology, land use and land cover, elevation, curvature, topographic wetness index, topographic position index, rainfall and slope) has revealed that “poor” and “moderate” groundwater potential constitute respectively 7% (58.59 km2) and 55% (460.35 km2) of the area, while “good” and “very good” groundwater potential represent respectively 35% (292.95 km2) and only 3% (25.11 km2) of the area. Our model results were validated using depth to water level (DWL) data of the Ghiss watershed and this comparison showed an acceptable conformity (70%) with GWPZs mapped for the Ghiss basin. It was also determined that the degree of conformity to generated GWPZ models using fewer parameters is comparable to those using more parameters. Our results indicate that two parameters (Lineament Density and Lithology) were sufficient to obtain a similar conformity (68%) with depth to water level data.