Annual Trends of Soil Moisture and Rainfall Flux in an Arid Climate Using Remote Sensing Data

Abstract

The water crisis is still a major issue in Qatar. Seawater desalination has been strongly implemented in the Persian Gulf region. However, it is costly and there is corrosion in piping materials and other equipment. Hence, there is a vital need to detect groundwater resources in Qatar. Various factors affect the variability of groundwater in Qatar including hydrogeological aspects, climate change, drawdown and abstraction, rainwater harvesting, desertification, and population growth. In this study, we employ the Famine Early Warning Systems Network (FEWS NET) Land Data Assimilation System (FLDAS) to monitor annual variations of soil moisture (SM) in the depth of 1–2 m (as an indicator of groundwater) and rainfall flux (RF) from 1982 to 2019. The results show that SM and RF anomalies were positive from 1982 to 2000 (except 1992). In contrast, these anomalies became negative during 2001–2019 (expect 2001 and 2018), implying the drawdown of groundwater resources. Drier years (i.e., negative RF anomaly) in the recent 19 years (2001–2019) reduced SM and led to a negative SM anomaly. The Mukaynis and Wadi Jallal regions (located in Al Rayyan and Al Wakrah municipalities, respectively) had the highest RF and SM from 1982 to 2019. The center-pivot irrigation systems close to the Mukaynis and Wadi Jallal regions indicate their accessibility to groundwater resources in Qatar. Moreover, these regions have the lowest risk of salinization and groundwater vulnerability. In addition, annual trends of groundwater storage (GWS) retrieved from the Gravity Recovery and Climate Experiment (GRACE) from 2003 to 2019 have been presented. This study is beneficial for detecting and monitoring groundwater resources for the sustainable management of water resources in arid environments.