Assessment of adequacy of the water distribution network of Gazipur pourashava

Abstract

Water distribution network of Gazipur Pourashava has been analyzed to determine the water demand and pressure at each node of the water distribution pipe network and the amount of flow in each pipe. The demand at each node was estimated using population data and per capita consumption rate. Amount of flow in pipes and pressure at various nodes were computed using EPANET2 software which is developed by US Environmental Protection Agency. In this computer programme number of pipes, number of nodes, Hazen-Williams coefficient, nodal demand, elevation of each node, node to node relations along with length, diameter, starting node number and end node number of pipes and pump capacity curve were supplied as input data. From the study the flow and pressure at each node as well as flow in each pipe were computed. Actual flow and actual pressure at each node and actual flow in each pipe was obtained by field survey. The amount of estimated water demand and actual supply and actual pressure and computed pressure in each node were compared. Similarly computed demand and actual supply in each pipe were compared. In this study it is observed that about 55% nodes have excess supply, 17% nodes meet required demand and 28% nodes experience deficient supply. Generally pressure in the distribution system under normal operating condition is very low. In this study it is also observed that about 11% nodes have sufficient pressure and the pressure of 89% nodes varies from 0.00 psi to 4.5 psi. The consumers nearer the pumping stations get more water and has tendency to waste water. Analysis of the water distribution network of Gazipur shows that the computed pressure is higher than the actual pressure measured in field. Given pumping capacity and extent of the water distribution network there is scope for improvement of supply situation. If the wasteful use of water and leakage of the supply system could be controlled, then all of the consumers could get water according to their required demand. This will require adequate management of water supply.