ABSTRACT
In order to produce water that is safe for drinking and less expensive, it is pertinent to construct a water distribution network for the community. A water distribution network is an essential hydraulic infrastructure which is a part of the water supply system composed of a different set of pipes, hydraulic devices and storage reservoirs. In this study a water distribution network was designed for Agiliti Community in Lagos State, Nigeria using the combination of both QGIS 3.14 and EPANET 2.2 with the aim of providing suitable and adequate water to the community.
The design criteria used in this study include a water supply of about 120 LPCD with a population projected for about 50 years, a maximum and minimum velocity of 1.5m/s and 0.5m/s, pressure head between the interval of 10-70 m. Data provided include a calculated diameter pipe diameter (800 mm), initial and final population for the year 2020 and 2050. The QGIS software was used to map the study area, create a digital elevation model for the study area, create a hydraulic model, calculate the length of pipes, allocate nodal demands to nodes and develop an EPANET INP for the distribution network. The EPANET carried out hydraulic analysis of the network by carrying out calculations of hydraulic parameters like velocity, unit head loss gradient, flow rate for the pipes and pressure, velocity for the nodes.
The result obtained showed that the velocity conforms to the maximum design velocity of 1.5m/s, the head loss of various pipes were below the calculated head loss of 15.6m, pressure head at the nodes were within the acceptable limit of 10 -70m making the network very adequate. Although, few pipes were experiencing low flow and velocity and these could be resolved by the installation of booster pumps, washout drains at those affected pipes. This study showed that the combination of QGIS and EPANET is very economical and time saving in the design of water distribution network. It was recommended that areas experiencing low flow should be looped in order to clear dead ends and designs should be carried out in more areas in Lagos State in order to validate the result obtained from this study.
