Population Forecasting for Design of Water Supply System in Injibara Town, Amhara Region, Ethiopia

Abstract

This research was conducted to explore the real problems occur in population forecasting of Injibara town and then pin points of the better means of potentially water supply development of Injibara town, Amara Regional state, Ethiopia.Population forecast is a scientific procedure to work out future population of given town. In order to sustain the town water supply scheme over the period of time and to propose the improvement in the existing town water supply scheme consumption and design parameters are depending on population of today and coming 2-3 decades. The design population is estimated considering all the factors governing the future growth and development of the project area in the industrial, commercial, educational and social and administration spheres. Special factors causing sudden immigration or influx of population should be considered.In present study population of four decades, from 2014, 2015, 2016 and 2017 are taken as base population and forecasted from the year 2019 to 2040. Increase in population over decade is calculated and present the population forecasting is done for five kebeles of Injibara town water supply systems, using average results obtained by Arithmetic progressive method, Incremental increase method, Geometric progression method and Exponential growth rate methods.The statistics of projected population is the basic criteria for the addition of diameter of pipe and length of distribution system. Also the magnitude of total head assigned to reservoir, power capacity of pump, treatment plant, systems of water supply and distribution system, per-capital demands of water and fire demand may be prescribed as design parameter of Injibara town water supply scheme.

Keywords: Arithmetic method, Incremental method, Geometric method and Exponential methods, in Injibara town.