Balancing Flood Hazard and Livelihood: A GIS–AHP–WLC Framework with Non-Monotonic River Scoring for Resilient Resettlement in Beledweyne, Somalia

Recurrent and increasingly severe flooding along the Wabi Shabelle River—displacing approximately 184,000 people from Beledweyne, central Somalia, in the 2020 Gu season alone—has made in situ reconstruction untenable and planned resettlement a central adaptation option. Site selection in this agropastoral context must simultaneously avoid the riparian flood corridor and preserve access to the river as the dominant livelihood resource. We develop a transparent, reproducible GIS-based Analytic Hierarchy Process–Weighted Linear Combination (AHP–WLC) framework over a 30 × 30 km region of interest at 30 m resolution. A hard safety mask (Height Above Nearest Drainage > 5 m and slope < 5°) is combined with six normalised criteria, including a non-monotonic, piecewise river-livelihood score, using literature-anchored AHP weights (consistency ratio CR = 0.004). Seven initial criteria were pre-screened with Pearson, Spearman and Variance Inflation Factor diagnostics (maximum |r| = 0.52, maximum VIF = 1.44), removing a perfectly collinear services-distance layer before weighting. Robustness was confirmed by a ±10% one-at-a-time sensitivity analysis with targeted river-weight and HAND-threshold tests, all criteria remaining very robust (|Δ| < 5%). The composite identifies 12,723 ha (14.3%) as highly suitable, resolving into 113 operationally meaningful candidate sites (≥5 ha; 95.6% of the highly suitable area). Candidate areas sufficient to absorb the 2020 displacement land demand (552–1104 ha) lie within 6 km of the city centre. The framework offers an operational, defensible foundation for resettlement planning in flood-exposed agropastoral cities of the Horn of Africa.