HYDRAULIC PERFORMANCE EVALUATION OF EXISTING WATER SUPPLY DISTRIBUTION NETWORK: THE CASE OF KOLFE KERANEO SUB CITY, ETHIOPIA

Abstract

The aim of proper design of water supply distribution network is adequate delivering of water to customers consumption nodes, Therefore the evaluation of hydraulic performance of water distribution network is important to identify the inadequacy of water transfer to a consumption nodes. Hence, the aim of this study is to evaluate the hydraulic performance of Kolfe Sub-city water supply distribution network. The existing water supply deficit and future water requirements, and junction pressure hydraulic, water velocity performance of the supply were evaluated. Water GEMS v8i, AutoCAD v2007i, ArcGIS 10.1, geographic positioning system Garmin72 and Microsoft excel sheet used. The water GEMS simulation results for both steady state and extended study period simulation of distribution network were related to pressure 44.61% for pressure value (≤ 15 mH2O), 37.84% for pressure value (15 - 60) mH2O and 17.55% for pressure value (≥ 60 mH2O) pressure head. In the same manner the velocity of pipe flow showed that 63.25% for velocity (≤ 0.6 m/s), 24.94% for velocity range (0.6 - 2 m/s) and 11.80% for velocity (≥ 2 m/s). The results indicated that the maximum and minimum velocity and pressure requirements was beyond maximum and minimum limit and hence, almost all junction is negative which displayed the inefficient hydraulic and the estimated total water loss is 23% for area. This problem are resulted from incorrect nodal placement and improper pipe connection during designing the system and when expanding the network to the newly established settlement area. On the other hands the existing water supply collection did not meet the average per capital water consumption rates. 20l/c/d which is 14.68l/c/d showing below standard of developing countries consumption rates. The existing water supply and demand gap of 25329.38 m 3 /d shown a great water shortage in the area, these indicating that, the predict water demand is greater than the current supply potential of water sources or water supply deficit. The current and predicted water demands were 12127.14 m3 /day and at the end of 2046 years will be 44946.68 m3 /day, whereas the available source is 19617.3m3/d. The mitigation measures for this interruption of water supply network, water loss and supply deficits is installing proper service of reservoirs, control water loss and seeking extra sources of water supply.