A combined approach to assess groundwater resources depletion in data-scarce areas: a case study in Wadi Zabid, Yemen

Steady groundwater depletion resulting from overexploitation of groundwater is a problem in many arid and semi-arid regions. Hydro-economic models are often used to study groundwater depletion, to evaluate water reallocation strategies and to develop scenarios for a more sustainable future. However, in data-scarce areas, there are insufficient time-series and spatial data available for such complex hydro-economic models. This PhD study develops and tests the usefulness and suitability of an alternative less complex and less data-intensive combined approach (incl. participatory rural appraisal, integrated data analysis, crop budget model and water balance model) to assess the different aspects of groundwater depletion that are tested in the study area in Wadi Zabid, Yemen. Overall, it concluded that the combined approach is useful to investigate the extent, drivers, the socio-economic impact of groundwater depletion, and to develop scenarios for groundwater storage recovery at the regional level, but it is not suitable at sub-regional level.