Optimal Design of Sprinkler Irrigation Systems for Medium-Scale Farms in South West Nigeria Using Simulation Modelling

This study develops and applies a simulation modelling framework for the optimal design of sprinkler irrigation systems on medium-scale farms in South West Nigeria, integrating hydraulic performance modelling, economic optimisation, and climate data to generate design specifications that maximise water use efficiency and crop productivity at minimum cost. Sprinkler irrigation adoption is increasing among medium-scale commercial farmers in the South West, but design quality is highly variable, resulting in systems that underperform their technical potential. A systematic simulation-based design optimisation approach can significantly improve design quality and economic outcomes. This study uses EPANET hydraulic simulation software integrated with a crop water requirement model and economic optimisation module to generate optimised sprinkler layout, pipe sizing, pump selection, and operating schedule for a 5-hectare reference farm located in three representative South West climatic locations: Ibadan, Akure, and Abeokuta. System designs are evaluated against uniformity, energy consumption, capital cost, and annual profit maximisation objectives using multi-objective optimisation. Sensitivity analysis examines the effect of water tariff, energy cost, and crop value on optimal design selection. Findings reveal that optimal sprinkler spacing differs significantly between the three locations due to wind speed differences, with tighter spacing required in the more wind-exposed Abeokuta location. The simulation framework reduces system capital cost by 18 percent and improves water use efficiency by 22 percent compared to conventionally designed systems. The study recommends simulation-based design tools for all medium-scale sprinkler irrigation investments.

Keywords: sprinkler irrigation design, simulation modelling, South West Nigeria, hydraulic optimisation, water use efficiency.