Identifying potential sites for rainwater harvesting for the local community – GIS/RS based approach: a case study of Olio sub-county - Serere District.

Abstract

Serere district has a mean annual rainfall of 1000 – 1500mm per year with two different rainfall seasons per year between March to July and August to October. The hard roof water harvesting is the traditional way of Rainwater Harvesting (RWH) that has been incorporated in most parts of Olio sub-county - Serere district. However, during periods of rainfall failure, drought begins to prevail and there is difficulty to cope up with the water demand during this period. The objective of this study is to apply spatial technologies to identify suitable sites for RWH in Olio sub-county – Serere district. To achieve this, parameters/factors that are suitable for locating potential sites for RWH were identified and analyzed as laid out in the literature. Soil Conservation Service (SCS) Curve Number method was used to map runoff potential areas for RWH and then Analytical Hierarchical Process (AHP) – based multi-criteria decision analysis was also used. Slope was being responsible for water losses through high rates of runoff water on the surface ground and drainage density was being responsible for outflow, this indicated that these factors were more important than the other factors. The other layers taken into account for analysis were land use land cover, soil texture and drainage. These thematic layers were all selected then overlaid according to their influence and various weights inorder to produce a suitability map for potential RWH sites for Olio subcounty – Serere district. Therefore, it was concluded that majority of the land was highly suitable (32%), very highly suitable (25%), moderately suitable (27%), marginally suitable (11%) and not suitable was (5%). GIS and remote sensing can be used in the exploration of rainwater harvesting sites in a scientific approach thus making decision making easier and accurate at both local and national scale level