Evaluation and redesigning of water supply system for Bombo military establishment.

Abstract

Population explosion in military establishments usually exert enormous pressure on the existing water supply system. The result is that the overall demand is usually not satisfied. Bombo military Establishment is experiencing this problem. This study presents a method for evaluating the performance of the water system of Bombo Military Establishment with respect to water demand, water supply, pressure distribution and pipe velocity and redesign a new system having an optimized design of a water distribution network using pipe diameter as a decision variable under the required demand loading and hydraulic conditions. Data was collected from field studies and an optimization model was formulated from the obtained information using pipe diameter as decision variable. Hydraulic conditions were simulated with EPANET 2.0 software w the optimization model was solved The water demand has been obtained by multiplying the population with the consumption rates prescribed in the water supply manual. The water supply has been calculated using the pump parameters at the borewells (pump rate and average pumping hours). The water distribution network was modelled in Epanet and the model has been used to evaluate the pressure and velocities in the network. In the design of an optimized water distribution network, different scenarios were tested to find the one which offered a better solution to the short comings of the existing network. It was found out that the current demand at Bombo Military Establishment exceeds the available water supply by 124m3/day which amounts to 45,260m3/day. The current demand is 360.4m3/day and the available supply is 236.4m3/day. The evaluation of the water distribution network showed that 52% of the nodes in the network operate at negative pressure. These negative pressures indicate that there is inadequate head within the distribution network for water conveyance to all the sections. Four of the pipes in the network have velocities that exceed the adopted velocity. These excess velocities are partly responsible for the leakages observed in the network. The results in this study revealed that the performance of the water distribution system of Bombo Military Establishment under current demand is inefficient. An optimized water distribution that rectifies the shortcoming of the existing network has been designed and was found be adequate in terms of pressure and velocities in the system. The optimized network will relieve the military officers and residents of the barrack from water stress. The sensitivity analysis shows that the optimized network will fail to perform efficiently at 200% increase in the water demand.