Evaluating urban policy: A GIS-based comparison of urban green space suitability model with Adama City’s Structural Plan

Urban green spaces (UGS) are critical for mitigating the negative impacts of rapid urbanization, yet land use changes and inadequate planning persistently threaten them. This study addresses this dual challenge in Adama City, Ethiopia, by first developing a scientifically robust site suitability model and then using it to evaluate the City’s existing urban policy. We quantified land use and land cover (LULC) dynamics from 1991 to 2021, revealing unsustainable urban sprawl as built-up areas expanded by 5,035.11 ha, a relative increase of 530.68%. This expansion occurred primarily at the expense of Farm land, and Shrub and bushes, which recorded absolute losses of 2,178.42 ha and 839.98 ha, respectively. These figures represent a relative decline of 9.17% for Farm land and a more significant 29.66% for Shrub and bushes. We then developed a GIS-based Multi-Criteria Analysis (MCA) model, integrated with the Analytical Hierarchy Process (AHP), to identify optimal sites for UGS development based on nine environmental, physical, and socio-economic criteria. The model classified 6.39% of the city as highly suitable and 25.41% as moderately suitable for UGS. Crucially, we compared these evidence-based results with the green space allocations in Adama’s Proposed Structural Plan (2017) by considering Plan Implementation Evaluation (PIE) theory. The analysis revealed a severe misalignment: only 26% of planned green space lies in suitable zones, while 74% is located in less suitable to unsuitable areas. Furthermore, the plan allocates only 17% of the total Adama City’s area to green space, falling short of the Ethiopian national 30% standard. This study highlights a critical gap between planning policy and scientific evidence in Adama City, demonstrating the urgent need to institutionalize geospatial suitability analysis within urban planning processes to foster sustainable and equitable urban development