Groundwater quality assessment using water quality index and geographic information system based in Sebou River Basin in the North-West region of Morocco

Abstract

The assessment of groundwater quality in regions with high economic activities is crucial for sustainable water resource management. The pressures on groundwater in the Sebou river basin are many and increasingly affecting the quality and the availability of groundwater. The identification of areas with groundwater of degraded quality is important for actions to be taken to reduce the pollution. The aim of this research is to assess and spatialize, using GIS, the groundwater quality in view of delineating polluted hotspots to be controlled by water resource managers. A water quality index (WQI) developed in Morocco has been applied to 81 water-quality monitoring stations with database of five water quality parameters from 1989 to 2017. The result indicated that the overall WQI, in most parts of the basin, was classified as medium to very bad. There were only small areas that showed good to excellent water quality. Three water quality parameters (NO3−, Cl− and electrical conductivity (EC)) underlie the degradation of groundwater quality as these parameters have shown very high correlation coefficients with the overall water quality index and minimum relative values of their sub-indices as 0.00 (very bad) for NO3−, as 0.00 (very bad) for EC and 11.7 (very bad) for Cl−. Intensive agricultural activities, untreated industrial and domestic wastewater and landfills could be responsible for degradation of groundwater quality in this area.