Abstract:
Rainfall intensity or depth estimates are vital input for hydrologic and hydraulic models
used in designing drainage infrastructures. Unfortunately, these estimates are suscepti ble to diferent sources of uncertainties including climate change, which could have high
implications on the cost and design of hydraulic structures. This study adopts a systematic
literature review to ascertain the disregard of credibility assessment of rainfall estimates
in Nigeria. Thereafter, a simple framework for informing the practice of reliability check
of rainfall estimates was proposed using freely available open-source tools and applied to
the north central region of Nigeria. The study revealed through a synthesis matrix that in
the last decade, both empirical and theoretical methods have been applied in predicting
design rainfall intensities or depths for diferent frequencies across Nigeria, but none of the
selected studies assessed the credibility of the design estimates. This study has established
through the application of the proposed framework that drainage infrastructure designed
in the study area using 100–1000-year return periods are more susceptible to error. And
that the extent of the credibility of quantitative estimates of extreme rains leading to food ing is not equal for each variability indicator across a large spatial region. Hence, to opti mize informed decision-making regarding food risk reduction by risk assessor, variability
and uncertainty of rainfall estimates should be assessed spatially to minimize erroneous
deductions.
