Spatio-temporal assessment of groundwater drought risk in the Souss-Massa aquifer: Impacts of climate variability and anthropogenic activity

Although the several studies carried out in the Souss Massa region, in terms of water resources, the assessment of the drought is still understudied, particularly groundwater drought which remains a gap in the previous studies. In this work, meteorological drought is investigated by using the standardized precipitation index (SPI) to shed light on its impact on groundwater drought occurrence. Thereafter, a combination of reliability analysis and standardized water level index (SWI) is used for groundwater risk modeling. Reliability analysis accounts for the safety and the failure of a system regarding loads, which take into account the external effects (withdrawals and recharge), and resistance which accounts for the system's capacity, thereafter values of Groundwater Drought Risk (GDR) and Environmental Hazard Index (EHI) are generated and then spatially distributed to assess groundwater risk for mild, moderate, severe, and extreme droughts for the whole region of Souss-Massa. Results showed a wavering between short dry and wet periods based on SPI, and demonstrated a weak correlation between the SPI and the SWI, hence the upward trend in the SWI is explained by the anthropogenic overexploitation of the aquifer. Furthermore, groundwater drought risk (GDR) values are low in the upper Souss and increase in the middle part and in the Massa basin, where significant effects are potentially expected. Based on the EHI results, it is confirmed that the Massa basin and the middle Souss are susceptible to groundwater drought and its environmental impact and need immediate intervention to properly manage the groundwater resources. This model could be helpful for the policymakers for better planning of water supply by providing useful information about the expected frequency and severity of water shortage in the studied area.

Keywords:
Groundwater drought, Reliability analysis, meteorological drought, anthropogenic activities, Souss Massa basin.