3-5 Probabilistic Estimation of Maximum Water Discharge Reaching Culverts under Extreme Rainfall Conditions

Abstrak

The increasing frequency and intensity of extreme rainfall events raise the hydrological loads on the drainage structures of transport infrastructure. In mountainous and foothill areas in particular, intense rainfall that develops over a short time can produce high peak flows in small catchments. This study proposes a methodology for the probabilistic estimation of the maximum water discharge reaching culverts under extreme rainfall conditions. The NASA GPM IMERG Final Run product is intended as the precipitation data source. IMERG data have a spatial resolution of 0.1°×0.1° and a temporal resolution of 30 minutes, and the Final Run is the version designed for scientific research. Extreme rainfall values are extracted using the Annual Maximum Series, and their return periods are estimated with extreme value theory. Design rainfall values are then converted into discharge, and the maximum flows corresponding to 10-, 25-, 50- and 100-year return periods are determined for culverts. The results provide the initial hydrological parameters for further probabilistic assessment of the hydraulic reliability of culverts.