Supattra Visessri. Frequency analysis of rainfall in the Prek Thnot River Basin, Cambodia. (). มหาวิทยาลัยเทคโนโลยีพระจอมเกล้าพระนครเหนือ. สำนักหอสมุดกลาง. : , 2567.
Frequency analysis of rainfall in the Prek Thnot River Basin, Cambodia
Abstract:
Floods are devastating natural disasters, causing extensive
impacts on lives and socioeconomics. The Prek Thnot River is a
tributary of the Mekong River in southwest Cambodia and is
prone to flood disasters. This study employs observed rainfall
data from eight stations in the Prek Thnot River Basin (PTRB) to
conduct frequency analysis. Five commonly used probability
distributions, including Normal (NOR), Log-Normal (LOG), Pearson
Type-III (PE3), Log-Pearson Type-III (LP3), and Extreme Value
Type-I (GUM), are assessed for their fit to the observed rainfall
data during extreme floods in the wet season (September to
November). Results from each distribution are compared
through graphical and numerical methods, including Quantile-
Quantile plots (Q-Q plots), to evaluate their performance.
Among these distributions, LP3 appears as the best fit at five
stations (63%), PE3 is the second-best fit at two stations (25%),
followed by GUM at one station (12%). Conversely, NOR and
LOG distributions exhibit outlier performances. Since LP3
distribution emerged as the most suitable fit at the majority of
stations and showed efficiency in capturing patterns of extreme
rainfall, LP3 was applied to fit the rainfall at all stations to
estimate the probability distribution in the PTRB. The
subsequent steps involve integrating the return periods of
rainfall and maximum monthly rainfall data to generate the
hyetograph of extreme events. Finally, the Inverse Distance
Weighting (IDW) interpolation method is applied to demonstrate
the spatial distribution of extreme events for return periods of
25, 50, and 100 years. The study is crucial for analyzing extreme
rainfall events and offers a crucial and comprehensive analysis
of extreme floods