Evaluating hydraulic performance of existing water Supply distribution system: a case study on addis zemen Town

Abstract

Water distribution network (WDN) is the components of water supply system that needs to design carefully because of cost involved and its significance. However, in many of the developing countries, the hydraulic and physical performance of water distribution network is inadequate to meet consumers’ demands and losses in system. Addis Zemen has been experiencing frequent and regular disruption of water supplies for days to a week. This study was conducted in Addis Zemen, to evaluate hydraulic performance of existing water supply distribution system of the town. Both primary and secondary data sources were used in this study. Primary data were collected though face-to-face interview with Addis Zemen Water Supply and Sewerage enterprise (AZWSSE) experts, field observations, photographs of relevant sites and infrastructures were taken. For secondary data collection, document review was used to collect valuable information. To analyze the data which is collected from different sources, both qualitative and quantitative methods was used. The computer software application that is Origin8 and excel was used to analyze the data obtained from office. The field survey data for distribution system was evaluated by using the engineering software called WaterCADv8i. The per capita domestic water consumption of Addis Zemen Town was found to be 12.98 l/c/d in the year 2015. The average water loss in Addis Zemen Town was 25.6%, showing that needs a matter of concern. 11.6% of the junctions were (>70 m) located around Michael area and Hospital due to low elevation. 1.9% of the junction was (<15 m) recorded 14 m around Hana due to high elevation.86.5% of the town that is the majority of the area has pressure within the optimum range (15-70 m) and the lowest velocity recorded was zero and the highest was 2.12 m/s during steady state analysis. 13.5% of the analyzed nodes get water at low pressure (<15 m), none of the node has pressure above 70m and only 86.5% have pressure within recommended limit (15 to 70 m) and velocity in major pipe parts was below 0.6 m/s during extended period simulation. The current water demand is 1398.68 m 3 /day and the demand at end of design period of 2025 years would be around 2926.33 m 3 /day. In order to achieve a 15 m minimum and 70 m maximum pressure, it is necessary to provide pressure controlling valve and establishing boosting station. Securing additional water supplies becomes an essential issue to meet the current water demand future demand