Optimization of the peri-urban water distribution network to meet increasing demand and future requirements. A case study of Kawaala village-Muyenga Subsystem,Kampala

Abstract

Increased water use has put extra strain on existing water distribution networks (WDNs) because of growing Peri-Urban growth due to urbanization and unplanned settlement on the outskirts of larger cities. Increased demand necessitates an unanticipated extension of the existing WDN, resulting in low water pressures at the network's far end. Kawaala Village has a high rate of intermittent water delivery, poor pressure, and no water supply in some locations. This has been ascribed to rising demand due to increased urbanization and industrialization, putting severe strain on the current network. When these systems unavoidably expand because of new connections, other issues arise, such as the possibility of transient flow conditions, which vary from fluctuating pressures and intermittent flows to water contamination and, in extreme cases, no flow at all. A case study of the water supply network of Kawaala village in Kampala, which lies on ten NWSC block maps each of 0.25 km2. The water supply network in Kawaala is primarily a curl-De-sac/looped pipe layout with dead ends. Muyenga Tank, with a capacity of 4000 m3, feeds the Kawaala network subsystem. A 300mm diameter transmission line runs along Hoima Road, feeding Kawaala settlement. Consisting of distribution main of pipe diameter sizes 50, 80, and 100mm. The main objective of the study was to optimize the existing water distribution network responsible for the provision of safe, adequate water supply and to meet the current and future demands in Kawaala village. The specific objectives majorly included assessing the physiological characteristics and hydraulic properties of the existing water distribution network for Kawaala village. The existing water distribution network was optimized using pipe diameter as the major decision parameter. In Epanet 2.2, the Demand Driven Analysis (DDA) was used to boost the pressures by optimizing the existing water distribution network. The findings revealed the need for the Kawaala supply network to be optimized to address the challenges of erratic flows and low pressures. The study's main conclusion was that the pressures at the network's dead ends were less than the permitted minimum of 10 meters of water column. During most times of the day, there was no water in the central area of Kawaala. As a result, the current water network was optimized to provide a model that gives nodal pressures of at least 10 meters of the water column. It is worth noting that, to optimize water supply service provision, proper management of discharge/production, head, and network configuration is required. The issue with Kawaala is not lack of water flow in the pipes but rather an insufficient distribution network, which has poorly designed diameters, low pressures, and no appurtenances like a booster pump to enhance flow to the network's high raised points.