Abstract
Assessment of storm is accomplished by the storm area and duration rather than a simple analysis using the rainfall data of the ground rain gauge stations. One of the best expressions for assessing storm is Depth-Area-Duration (DAD) analysis. The DAD analysis provides a powerful, objective, easy-to-understand three-dimensional perspective of storm rainfall, and is applied to estimate probable maximum precipitation (PMP) for the design of hydraulic structures. However, a general DAD analysis is prone to generate subjective errors to divide and accumulate sub-basins. Further it is difficult to understand the impact of recent localized and intensive storms due to the climate change. This research carried out to obtain DAD analysis of high accuracy in the small basin and relieve errors that occur in the analysis. Methods to estimate areal rainfall are the inverse distance weight (IDW) and ordinary kriging (OK), while methods to accumulate area are the box-tracking and the point-tracking. The merits and demerits of these methods are discussed.
