Evaluation of the Performance of the Water Supply Distribution System, the Case of Bishoftu Town, Ethiopia

Abstract

In developing countries, urban water supply infrastructures are often under a lot of burden, mainly due to rapid population growth and industrialization. System underperformance, operation and management problems, and limited technical capacity of the utilities are some of the serious issues in the water supply sector that demand close follow-up and action. Thus, the objective of this study was to assess the overall water supply performance of Bishoftu Town of Ethiopia, by evaluating the water supply coverage, the hydraulic performance of the distribution system and the level of customer satisfaction. The methodology used to evaluate the hydraulic parameters pressure and velocity was Bentley Water GEMS v8i software that used topo data of infrastructures, pipe size, water demand, and population size of the research area and digitalized to undertake the analysis. General satisfaction of the population was done through collecting data by use of prepared questionnaires and analyzing using stata/SE 14.2 software, which the data collected from all kebeles and the random sampling methods was implemented for analysis. The research result shows that the average daily per capita water consumption and water supply coverage of the town found to be 44.85l/c/d and 84.9%, respectively. On the other hand, the results of the extended period simulation at peak hour consumption indicated that the performance of the distribution system connected to pressure found to be 3.16% of the nodes acquired pressure of 15m head, 40.91% nodes have 15m - 70m, 31.62% have 70m - 100m, and 24.31% have >100 m. On the other hand, the system's performance during peak hour consumption showed that 51.7% of the pipes had flow velocities below 0.2 m/sec, 24.5% had velocities between 0.2m/s and 0.6 m/s, 19.50% had velocities between 0.7 and 2 m/sec, and 4.83% had velocities above 2 m/sec. With regard to customer satisfaction, the study found that only 28.57% were generally satisfied with the current water delivery system, 41.88% were neutral, and 29.55% were dissatisfied. From the result, the performance of Bishoftu town water supply system has found to be low velocity, high pressure and low level of overall satisfaction in quantity, quality and continuity for main pipelines. The high pressure resulted due to looping system of main pipelines and two methods of water distribution system pumping and gravity system; this might result in water wastage in the secondary and water collection point. On the other hand, low velocity in the main pipeline system is due to looping system which similar research also revealed that looping system of main pipelines in the town result in low velocity which is the source of water quality deterioration. Bishoftu town enterprise can undertake the improvement of the water supply system considering the detail finding of this thesis, under taking assessment on nonfunctional water sources which was not consider during the system analysis, assessment on new connected service area, and evaluation of water quality issues to ensure the a sustainable water supply system for future development. From the research, it is recommended that the enterprise could undertake improvement of the system through connecting pressure reducing valve, Gate valve, and use of appropriate pumps specifications and changing old pipes with new ones at recommended areas.