Developing a daily maximum rainfall map based on regional frequency analysis and bayesian inference: a case study in Quang Nam province

Abstract

    The design and testing frequency of the daily maximum rainfall is crucial in hydraulic and hydropower structures design and management. In Vietnam, short period of gauged rainfall data reduces the reliability of the estimated results in the design and testing daily maximum rainfall. In addition, due to the sparse distribution of the rain gauge network, the rainfall measurement does not reflect the actual value at each catchment. To overcome this limitation, this study uses a regional approach and a Bayesian inference to increase the number of the gauged rainfall data samples in order, to increase the reliability of the estimated frequency and develop the daily maximum rainfall map, which can be applied in the hydraulic structures design and management. The study area is Quang Nam province with 16 rain gauges, combined with 9 rain gauges in the neighboring provinces. The results demonstrate that the developed daily maximum rainfall maps are consistent with the precipitation characteristics and distribution in the study area. These results also provide the estimated rainfall level in any location corresponding to the design frequency or the return period.