Developing a climate-resilient GIS-based framework for irrigation site selection in Dedza district.

Abstract

Climate change poses a significant threat to agricultural sustainability in Malawi, particularly in Dedza District, where rainfed farming systems are highly vulnerable to erratic rainfall and rising temperatures. While irrigation offers a pathway to resilience, current site-selection approaches remain fragmented, relying on outdated datasets, coarse-scale assessments, and expert opinion, with limited integration of climate projections or socio-economic realities. This study developed and validated a climate-resilient irrigation site selection framework for Dedza District using an integrated Geographic Information System (GIS)-based Multi-Criteria Decision Analysis (MCDA) approach, guided by the Analytic Hierarchy Process (AHP) and informed by both qualitative and quantitative data. Key factors influencing suitability included proximity to rivers (19%), land use/cover (15%), landform (15%), and rainfall deficit (14%), with stakeholder insights reinforcing the importance of water access, infrastructure, and climate variability. The framework integrated 12 reclassified and weighted spatial layers, achieved strong internal consistency (CR = 0.08), and was validated, with 97% of existing irrigation sites falling within areas classified as suitable. Future climate projections under SSP5-8.5 revealed a sharp decline in highly suitable land from 37.25 km² (2000–2020) to 0 km² by the 2070s, highlighting the urgency of adaptive irrigation planning. The novelty of the framework lies in combining literature and stakeholder-derived qualitative inputs with climate projections to produce forward-looking suitability maps, bridging a critical gap in Malawi’s irrigation planning. Limitations include the exclusion of groundwater due to data constraints, reliance on coarse-resolution climate datasets, and the absence of crop-specific modelling, which should be addressed in future studies. The study recommends integrating this framework into district and national irrigation planning, prioritising moderately suitable zones, strengthening institutional capacity, and extending the model to other districts, thereby advancing Malawi 2063’s vision for climate-smart, food-secure agriculture.