Quantitative assessment of non-revenue water prevalence in Nyarwodho GFS in Uganda

Abstract

Studies that were conducted reported on impacts of Non-Revenue Water (NRW) on the sustainability of piped water supply systems. Millennium development goal No.7 (MDG 7) and sustainable development goal No. 6 (SDG 6) are among the many strategies adopted globally to ensure access to safe water by the global population and particularly developing countries including Africa. However, water utilities across nations have their efforts hampered by Non-Revenue Water prevalence. Narwodho GFS is a gravity flow system that abstract water from the river Namrwodho at the border between DRC and Nebbi District, and a convenctional treatment facility with 4000m3/day treatment capacity before transporting to the 9 supply zones in Nebbi and Pakwach Districts. The system is experiencing high NRW prevalence which affects service delivery. An investigation was conducted to assess and quantify NRW prevalence in the scheme in order to understand the causes of NRW hence develop mitigating strategies. Field surveys were conducted to evaluate the real situation hence develop strategies for mitigation. Billing data were obtained from the records of scheme operator while water production records were obtained from the treatment plant superintendent. Pipes were inspected to understand their characteristics including the pressure ratings and the trenching depths and their contribution to NRW prevalence in the scheme, Hydraulic modeling and analysis was conducted to understand the pipe flow behavior in contributing to NRW, and amongst the software’s used were; AutoCAD Civil 3, EpaCAD, and EPANET 2.2 for data manipulations and analysis. The employees of the scheme and water users were interviewed in order to understand the impacts of NRW on them. The findings revealed that the NRW trend in Nyarwodho GFS were; 2018 (93.36%), 2019 (80.25%), 2020 (77.79%) and 2021 (75.34%) contrary to the 39% reported by the scheme through Utility Performance Monitoring information system (UPMIS) portal, with an 18% NRW reduction was recorded in a period of four years. Pipe bursts on the transmission pipeline was observed to have contributed the most to NRW in the scheme, and this was particularly exuberated by; over supply at night, installation of low pressure rating uPVC pipes in some sections, and shallow trenching that has been made even shallower by soil erosion amongst others. Users reported intermittent supply where they spend days or weeks without water, while the scheme staffs have low remunerations due to low revenue collections. Mitigation measures were recommended to water utility providers which among others include but not limited to; regulating night supply, financial support to the utility, adopting preventive measures, good asset management, timely supply of repair materials, replacing pipes of low pressure ratings, staff capacity building, motivation of employees, rewards for reporting vandalism, regular user sensitization and engagements, involvement of local leadership and users in the affairs of water supply, and creating customer what sup group for reporting breakdowns.