Sustainability assessment of urban water supply distribution system: a case study of bichena town, amhara region, Ethiopia

Abstract

Water is a vital resource no matter where in the world we live. But two out of five people without access to an improved drinking water source live in Africa. The lowest levels of drinking water coverage are in Sub-Saharan Africa (50–75%). In sub-Saharan Africa the proportion of people with access to potable water supply and adequate sanitation is actually low. Based on 2009/10 data the regional water supply coverage is not exceeding 60%. This indicates that 40% of the people have no access to clean water. Nowadays sustainability assessment is crucial issue and Ethiopian government give consideration on urban water supply sustainability by the second growth transformation plan. Sustainability of urban water supply is major challenge facing many towns generally in Ethiopia. So, the study focuses on sustainability assessment of urban water supply distribution system of Bichena Town by investigating technical performance indicators which were velocity and pressure in the water supply distribution system. Watergemsv8i was used for simulation the distribution water supply network. Arc GIS 9.3 was used for mapping. A methodology was presented for determining sustainability indices for pressure and velocity in water distribution systems. These sustainability indices were based upon performance criteria including reliability, resiliency, and vulnerability indicators. The result of the study area was analyzed by excel. From the result of the analysis the per capita consumption of Bichena town was 13.3 liter per capita per day which was lower than World Health Organization 2008 standard and Ethiopian government second growth transformation plan. The value of pressure and velocity were used to determine reliability, resiliency and vulnerability performance criteria. The overall sustainability index of Bichena town water supply was 0.46 which shows the unacceptable level. The study findings of indicators show that Bichena town water supply distribution system was not sustainable. Therefore the water supply should be redesigned and additional borehole should be drilled in order to meet customers demand. Since velocity of water supply of the study area was low and affect water quality of the distribution system, pipe size should be modified. Additional boreholes should be drilled.