•  
  •  
 

Keywords

probability distributions, IMD reduction formula, return periods, rainfall duration, easy ft software 5.0

Document Type

Research Article

Abstract

Rainfall intensity is an essential parameter in the design of any hydraulic structure. The IDF curves are used to design hydraulic structures such as culverts, bridges, roads, urban drainage systems, and many more. Colonial masters developed the frst IDF curve for Kano State based on records of 1938 - 1944 (6 years) followed by Oyenbade (1982), and since then, it has not been reviewed or updated. As a result of changes in rainfall patterns that have taken place over time and the climate change, the Oyenbade IDF curves might no longer be suitable for hydraulics design in Kano State. Therefore, this research aims to develop the new IDF curves and establish empirical equations of rainfall intensity that can be used for safe and economic hydraulics design in Kano State. India Meteorological Department (IMD) reduction formula was used to disaggregate maximum daily rainfall of Kano gauge station into the rainfall of shorter durations. Lognormal probability distribution was found to ft best the data set of all the durations using Easyft 5.0 software and estimate rainfall intensities for 2, 5, 10, 25, 50, and 100 years return periods. It was found out that rainfall intensities increase with the increase in return periods but decreases with an increase in duration. The coefcient of determination ‘R2 ’ for all return periods indicated a strong relationship in IDF models developed. Hence, the new IDF curves developed should estimate rainfall intensities for hydraulics design in Kano State. The derived IDF models could be used for better results and accuracy.

html

Publication Date

30-6-2021

First Page

10

Last Page

22

Download

Share

COinS