Innovative and Sustainable Water Engineering for Agricultural irrigation in Sub-Saharan Africa: A Systematic Review of Irrigation Technologies and Their Productivity Impacts under Water Scarcity

This paper aims to review existing studies on innovative and sustainable water engineering for agricultural irrigation technologies and their productivity impacts under water scarcity in Sub-Saharan Africa (SSA). This study analyzed and reviewed 50 articles and reports on agricultural irrigation technologies using a systematic literature review, PEO, PRISMA, SALSA and impact-effectiveness frameworks methodologies. Data sources included Scopus, Web of Science, AGRIS, Google Scholar, and ScienceDirect and institutional repositories for instance FAO, World Bank. The findings indicate that although a wide range of irrigation technologies are being implemented in different ecological and socio-economic settings in Sub-Saharan Africa, including drip and solar-based systems, and traditional and natural systems, notable research gaps were identified such as sustainability landscape of irrigation research is still very much characterised by substantial structural and content-related gaps, omission of the behavioral and perceptual aspects of adoption, governance and institutional arrangements, digital and remote-recording practices are making inroads in irrigation systems. The study suggests that technical success is commonly limited by socio-institutional and environmental factors, including under-financing, poor training, and policy fragmentation. The study aggregates empirical evidence and maps implementation challenges, offering a timely policy-relevant basis to rethink strategies for irrigation in SSA. It provides a much-needed typology and a set of principles to help guide researchers, practitioners and decision-makers toward sustainable, scalable and climate-smart irrigation solutions for the region. In addition, the findings will be useful for policymakers, industry stakeholders, and educators in developing effective agricultural irrigation technologies. Key words: Sustainable irrigation, water engineering, Sub-Saharan Africa, smallholders, systematic review, water productivity, climate adaptation.