Gratien Twagirayezu

Generation of rainfall Intensity Duration Frequency (IDF) Curves Gratien Twagirayezu

The hydrologic cycle is fluctuating wildly due to the production of greenhouse gasses which cause variations in intensity, duration and frequency of rainfall events. By pinpointing the potential effects of climate change and acclimating them is way to reduce regions susceptibility. Since rainfall characteristics are often used for planning and designing of various water resources project. It is crucial to review and update rainfall characteristics for future climate situations. This study aimed to create new IDF curves of Upper Nyabarongo catchment using Indian Meteorological Department (IMD) empirical reduction formula. Umbel's Extreme-Value distribution method was used to develop IDF curves and equations. It was revealed intensity of rainfalls decreases with increase in rainfall duration. Further, a rainfall of any given duration will have a larger intensity if its return period is large. In other words, for a rainfall of given duration, rainfalls of higher intensity in that duration are rarer than rainfalls of smaller intensity.