Application of intensity-duration-frequency curves in flood mitigation for rural communities: a case study of Ibido, Ogun State, Nigeria

Abstract

Flooding poses significant threats to rural communities in Nigeria, leading to property damage, infrastructure deterioration, and disruptions to livelihoods. This study develops hydrologic parameters for flood risk mitigation in the Ibido community by establishing Intensity-Duration-Frequency (IDF) curves and estimating peak flood discharges for various return periods. Historical rainfall data (1982-2022) were analysed using probability distributions, with the log-normal distribution identified as the best fit based on goodness-of-fit criteria. The study further employed the Rational Method for peak flood estimation and developed design parameters for effective drainage infrastructure. This study found that the predicted design storms for return periods of 5 to 100 years ranged from 136.12 mm to 230.29 mm. The drainage area was 1.0364 km2, with a time of concentration of 1.35 hours and a runoff coefficient of 0.80, resulting in peak flood discharges ranging from 18.47 m3/s to 31.25 m3/s. Future research should incorporate high-resolution terrain data and real-time monitoring for enhanced flood resilience in rural communities like Ibido.