ASSESSMENT OF WATER LOSSES FROM INTERMITTENT WATER SUPPLY SYSTEM: CASE STUDY OF MERSA TOWN, EASTERN AMHARA REGIONAL STATE

Abstract

Mersa town is one of the commercially fast growing towns of Amhara Regional state having insufficient and inadequate supply of water and poor water management practice. Financial, management, fast population growth and technical constraints are the main bottlenecks that hamper the town from satisfying the highly growing needs of its residents. The main objective of the study is to investigate water losses and devise strategies to minimize water losses in the main and distribution system of Mersa town. A water audit software were applied to analyze the water losses. And also water meter tests and discussion with local experts were carried out. Additionally, EPANET software was used to adjust the pressure in the distribution system. In so doing, first of all water balance at both entire town and the stated sub-system levels was conducted to visualize the loss of water, indexing the leakage level and evaluating all the performance indicators. Water supply for the entire town and water consumption as aggregated from individual customer bills was used to evaluate the total water loss at the entire town and at the sub distribution system levels, respectively. Finally, potential causes and possible solutions of water losses in the town water supply system were assessed, accordingly the water losses strategies are designed and the system pressure is adjusted. Quantifying, characterizing the factors that lead to water losses in a town water supply system is by its nature require well managed network and reliable data. As a result, cross checking and verification of data was the most significant problem faced during the study. The paper comprises two major parts; namely Water loss Analysis part and Modeling part. From water loss analysis part, the present water supply network services of Mersa town is not sufficient for all residents, the system pressures are low and all the areas have intermittent services. The annual water loss of Mersa town in terms of percentage was greater than the acceptable level which is 10% that cannot be removed. The infrastructure leakage index value was obtained to be greater than an ideal value of 1. Accordingly, there is a room for Mersa water supply and sewerage services to target for leakage reduction even for the current situation of the system. Besides, there is similar room for leakage reduction due to excessive pressure at some nodes with pressure above the recommended maximum for leakage of 80 m almost all the day as pointed out from the modeling part. MWSSS shall establish clear control strategy and improve the system besides harnessing new supply sources to fill the demand supply gap and reliable data base conductive.