Abstract
ESTABLISHMENT OF RAINFALL INTENSITY-DURATION-FREQUENCY EQUATIONS AND CURVES USED TO DESIGN AN APPROPRIATE AND SUSTAINABLE HYDRAULIC STRUCTURE FOR CONTROLLING FLOOD IN NYABUGOGO CATCHMENT-RWANDA.
Jean Claude Nizeyimana, Shanshan Lin*,O. Munyaneza*, Fabrice Ndayisenga, Gratien Twagirayezu, Junaid Khan, Phyoe Marnn, Dawuda Usman Kaku, Bazel Musaed Abdullah Al-Shaibah, Ali Rajeh Hussein Ahmed Al-aizari, A. A. M. Yousef, O. Irumva
ABSTRACT
Intensity Duration Frequency curves describe the connection between rainfall intensity, rainfall duration and return period. Intensity-Duration-Frequency (IDF) curves are one of the most often applied implements in water resource engineering in areas aimed at controlling floods. In particular, IDF curves for precipitation answer problems of improper drainage systems or conditions and extreme characters of precipitation which are the main cause of floods in Nyabugogo catchment. This study aims to establish Rainfall IDF empirical equations, curves and predicted peak rate of runoff (Qlogy) equations that will be used for designing appropriate and sustainable hydraulic structures for controlling flood in Nyabugogo catchment. Goodness of Fit tests revealed that Gumbel’s Extreme-Value Distribution method appears to have the most appropriate fit compared with Pearson type III distribution for validating the Intensity-Duration-Frequency curves and equations through the use of daily annual for each meteorological station. The findings of the study show that the intensity of rainfall increases with a decrease in rainfall duration. Additionally, a rainfall of every known duration will have a higher intensity if its return period is high, while the predicted peak rate of runoff (Qlogy) increases also with an increase in the intensity of rainfall.