Monitoring Yemen’s groundwater depletion using satellite data

Water is a precious commodity in Yemen, with much of the country’s resources locked away in groundwater. The growth in borehole drilling and the recent adoption of solar-powered groundwater pumps have intensified pressure on this vital resource, with 90% of groundwater exploitation supplying irrigated agriculture. Unfortunately, recent data on groundwater abstraction and recharge are scarce, making it difficult to pinpoint the areas most affected by groundwater depletion and assess whether the problem is worsening.

Earth Observation (EO) data offers promising insights. By providing gridded recent data on rainfall, cropland, evapotranspiration, and other variables, EO data helps estimate groundwater recharge and abstraction rates, as well as the overall water balance at the catchment scale. 

HR Wallingford led a consortium using EO data to estimate the water balance for catchments across Yemen with significant irrigated agriculture, using Water Accounting + tools developed by Delft IHE. We also developed a composite indicator of groundwater depletion risk by overlaying depletion data with population and vulnerability indicators.

While the use of EO data comes with challenges, such as the need for field data to validate EO data products, this approach provides insights that are simply unattainable at the resolution and timescales of ground-based data in Yemen. Groundwater systems, agricultural practices, and water exploitation and management in Yemen are unique and complex. We collaborated remotely with Yemeni organisations and development partners throughout the process to ensure our work accurately reflects the challenges faced. The information has been compiled into a publicly accessible website, Yemen Groundwater Risk, to disseminate the outputs.