ASSESSEMENT OF URBAN WATER SUPPLY ADEQUACY AND EVALUATION OF HYDRAULIC INTEGRITY (THE CASE IN SHONE TOWN, HADIYA ZONE SNNPR STATE

Abstract

importance of water to living things cannot be overemphasized. Providing adequate and sustainable water supply to the rapidly growing population in expanding and developing towns of Ethiopia is getting a challenge from time to time. The main objective of this study focuses on assessing water supply adequacy and evaluating hydraulic integrity through: analysis of water supply coverage, assessing water supply source, assessing system water loss, analysis of current & future water demands and evaluating hydraulic integrity of existing water distribution system by using WaterGEMS software simulation in Shone town, which is located at Hadiya zone, SNNP Regional State of Ethiopia. Both primary and secondary data were collected and used during study and analysis. The primary data collected includes existing pipes network GPS data and water pressure gauge readings from customer faucets. The secondary data collected includes existing water supply system information, type and number of existing mode of service, water production & consumption data, pump & BH data and financial transactions from customer billings. The methods employed during the study include, collecting and analyzing both primary and secondary data & tools used were GPS, Water GEMS Connect edition, ArcGIS 10.3, AutoCAD and statistical analysis. Based on this pipe networks were created, model developed and water GEMS simulation was conducted to test and analyze the hydraulic integrity of existing water distribution system. Accordingly, the total calculated average per capita domestic water consumption of the town for the year 2023 was 15.76 l/capita/day and the amount of water lost from system as non-revenue (NRW) was 106,963.16m3 (36%).The current year 2023 and future 2042 maximum day water demand of the town was 3899.27m3/d and 11615.11m3/d respectively but the amount of water supply from the source to the system is only 1267.20m3/d. After modeling & simulation in peak hours, the distribution system analysis showed that 25.58% of the junctions have above the maximum and 51.16% of the junctions have below the minimum operating pressure and 1.5% of the pipes have above the maximum and 43.28% of the pipes have below the minimum permissible velocity ranges respectively. Therefore, the calculated average per capita domestic water consumption only satisfies 26.27% compared to 60 l/c/d set by GTP-II of the country for category 3 urban town like Shone and the town is under sever conditions in water loss balance as compared to GTP-II target to minimize (<20%), moreover, the amount of water supplying to the system from source can only satisfies 32.51% for current and 10.91% for future demands in 2042. So this points out that availing supplemental water sources becomes the key gap to meet the current and future water demand of the town. The hydraulic analysis result of the system indicates, presence of various shortcomings to existing water supply system in terms of hydraulic integrity, these are oversized and undersized pipes, irregular flow velocity and low pressure (-22.25m H2O) and extremely high pressure values (108.96m H2O), low source water supply and improper pipe size. Moreover, performance of the model was evaluated using statistical evaluating tool. As the result, the value of coefficient of determination (R-value) in pressure calibration calculated was 0.998. Therefore, findings of this research is promised to help the stakeholders to intervene and take timely actions by upgrading the existing water supply system to meet the current and future water demand of the town