Unveiling innovative solutions to unlock underutilized groundwater and rainwater potential in Tanzania

Groundwater access, reliable rainfall, rainwater harvesting, and climate-smart technologies are vital for sustainable food production and enhancing water resilience. However, fragmented operations, limited knowledge, and insufficient cross-sectoral collaboration hinder the implementation of integrated solutions to improve water access and agricultural productivity. This study investigates the underutilized potential of groundwater and rainwater resources in supporting agricultural production in Tanzania's southern and northwest highlands, regions facing increasing water demands and climatic stress. Employing a mixed-methods approach, data were collected across four agriculturally productive districts through household surveys, key informant interviews, focus group discussions, field observations, climate data interpolation, WEF-Nexus index analysis, and an extensive literature review. Quantitative data were analyzed using SPSS 20 and Microsoft Excel, while qualitative data were processed through thematic and trend analysis. The study reveals that over 70 % of households rely on rainwater harvesting, although this is primarily done through rudimentary systems. Groundwater use is widespread, yet 62 % report declining yields due to overuse and poor management. The adoption of micro-irrigation remains limited, but it statistically improves productivity (p = 0.030). The findings highlight significant barriers to water resource utilization, including financial constraints, inadequate technology, siltation, declining groundwater levels, and weak governance structures. Climate variability and anthropogenic pressures further exacerbate these challenges, limiting the effectiveness of rainwater harvesting and groundwater management. Moreover, knowledge gaps and limited community capacity undermine the adoption of innovative and climate-smart water solutions. Despite these challenges, the study underscores the substantial potential of rainwater and groundwater to enhance irrigation systems, promote water security, and increase agricultural resilience. It recommends robust water management systems, infrastructure, capacity-building investments, policy reforms to incentivize technology adoption, and community-driven approaches to unlock the full potential of these resources. These measures are critical to achieving sustainable development goals and ensuring food and water security. Thus, unlocking the potential of these water sources requires integrated governance, investment in resilient infrastructure, and capacity-building among local communities.