Identification of rainwater harvesting areas for development of irrigation water resources in Uganda :

Abstract

Globally, the increasing water scarcity due to climate change is becoming a major threat for dry land irrigation agriculture development. This is a similar case with Karamoja, one of the poorest and most disadvantaged regions in Uganda facing a water crisis with only one crop season from April to November. Rainwater harvesting (RWH) is an emerging sustainable solution to mitigate water scarcity and enhance irrigation agriculture in such regions. However, identifying the suitable areas for RWH is quite difficult, time consuming and requires technical skills. This research aims to model and identify RWH areas using integrated multi-disciplinary approach of geographical information systems (GIS) and hydrological modeling techniques. Spatial data, including rainfall, topography, soil types, and land use, were analyzed to develop a comprehensive understanding of the region’s hydrological characteristics. The crop water needs of two major crops; maize and sorghum were estimated using PM-FAO method in QGIS and Excel. Soil conservation system curve number method was employed to estimate runoff, water availability and runoff capacity, considering different water demand scenarios for irrigation agriculture. The model considered factors such as catchment characteristics, water retention structures, and cropping patterns to assess the feasibility and potential impact of rainwater harvesting systems. The results show that 6.4%, 40%,2.9%, 52.9%, and 0.9% of land are not suitable, marginally suitable, moderately suitable, suitable and highly suitable respectively for RWH with 42% of areas ideal for irrigation agriculture development. Most of the area’s slopes support RWH and irrigation agriculture, as confirmed by the validation test. The study findings provide valuable insights into the suitability of different areas within the Karamoja region as catchments for RWH. The highlighted locations where RWH infrastructure can be implemented to support irrigation agriculture and agro pastoralism thereby contributing to food security and improved livelihood in the region. Above all the research findings contribute to the scientific knowledge and understanding of RWH as a viable and climate solution for agricultural development in semi-arid regions.