A Multicriteria Approach to Regional-Scale Planning of Water Harvesting in Arid Regions of Somalia

Somalia is one of the most arid countries in the world. Here, Water Harvesting (WH), namely the collection and storage of runoff water for productive use, can represent a suitable solution for enhancing the effect of erratic rainfall patterns. A major barrier to WH implementation is the difficulty of selecting suitable sites for such small- to medium-scale low-cost infrastructures, especially for large areas where it has not been implemented before. This study presents a Multi-Criteria analysis for selecting the best sites for WH Ponds and Sand Dams for seven regions of Northern Somalia (Awdal, Bari, Nugaal, Sanaag, Sool, Togdheer, and Woqooyi Galbeed). Criteria and weights for the analysis were based on existing literature and expert elicitation from interviews with FAO-SWALIM officers. The Analytical Hierarchy Process (AHP) was used to minimize the uncertainty in the weights selection; the analysis was validated using over 100 existing WH structures. Finally, the biophysical suitability to WH of different catchments in the study area was evaluated, showing good potential on the North-western side and some potential along the Eastern coast. This approach, covering half of the country, represents a cornerstone for any lower-scale investigation and can be replicated in any similar context, even if data is scarce. The study was funded by FAO LETTER OF AGREEMENT # 043/2024 - Desk study on “Best Siting of Water Harvesting Structures in Somalia with a focus on its arid parts”.