Use of remote sensing to determine rainwater harvesting sites for piped micro-irrigation schemes in Chimanimani District, Zimbabwe

Abstract

The eastern highlands of Zimbabwe, particularly Chimanimani District, are endowed with natural water bodies such as springs, pools, wetlands, puddles and river systems, which are potential sources of water for irrigated farming. Despite this, water challenges continue to exist due to rainfall seasonality and lack of suitable water harvesting sites. This calls for solutions to harness water in long-lasting sources to support the piped micro-irrigation schemes. These schemes are pillars in agricultural interventions such as horticulture, livestock farming, fish farming and beekeeping. This study therefore, determined potential rainwater harvesting (RWH) sites in Chimanimani District using geospatial techniques. Water pixels from Landsat 8 images were extracted using the normalised difference moisture index (NDMI) and normalized difference vegetation index (NDVI). Potential RWH sites were classified into land-based zones, wetlands and natural water bodies. Findings show that land-based zones cover 27.53%, wetlands cover 24.65% and water bodies cover 6.11% of the district. The study also indicates that integrating geographic information systems with remote-sensing tools is a useful approach in identifying RWH sites. Thus, this study provided a spatially explicit approach and presents a suitability map for RWH in Chimanimani District.