DESIGN AND ANALYSIS OF A WATER DISTRIBUTION NETWORK USING EPANET IN OSUN STATE POLYTECHNIC IREE

ABSTRACT This study designed and analysed an efficient and sustainable gravity-fed water distribution network for Osun State Polytechnic, Iree, using EPANET 2.2 software. The campus currently lacks a functional centralized water supply system and relies on scattered boreholes, resulting in persistent water scarcity, especially during the dry season. A realistic per capita demand of 230 litres per person per day was adopted for the estimated population of 9,000 (students and staff), yielding an average daily demand of 2.07 million litres and a peak instantaneous demand of 52 L/s under a diurnal pattern with a peak factor of 2.2. The proposed network comprises eight existing boreholes modelled as fixed-head reservoirs at 565 m total head, a centrally located 20 m diameter × 12 m elevated storage tank, and zoned distribution to 23 demand nodes via 200–250 mm transmission mains and 150 mm local laterals. Extended-period simulation over 24 hours revealed that residual pressures remained between 54.2 m and 92 m throughout the diurnal cycle, comfortably exceeding the design target of 52 m and Nigerian standards (NIS 554:2007; NIS 573:2015). The elevated tank exhibited a maximum drawdown of 3.29 m (27.5 % of usable volume) during peak hours, with full recovery overnight and no encroachment on the 3.0 m emergency reserve. Sensitivity analysis confirmed system resilience: a 30 % demand increase (2035 projection) reduced minimum pressure to 49.8 m; a 25 % source yield drop lowered it to 51.1 m; and single-borehole failure had negligible impact (minimum pressure 53.6 m). The gravity-driven, multi-source, nearest-node-only topology eliminated the need for booster pumping under all tested conditions, offering a cost-effective, energy-efficient, and highly redundant solution. The study concludes that the proposed network is technically feasible, hydraulically robust, and capable of meeting current and foreseeable future demands of Osun State Polytechnic, Iree, while providing a scalable model for similar semi-urban tertiary institutions in Nigeria. Keywords: Water Distribution Network, EPANET, Gravity-Fed System, Elevated Storage Tank, Diurnal Demand Pattern, Pressure Compliance, Osun State Polytechnic Iree