Flood frequency analysis in ungauged areas

• Main Authors: Po-Chiang Lin, 林柏強
• Other Authors: Kwan Tun Lee
• Format: Others
• Language: zh-TW
• Published: 2008
• Online Access: http://ndltd.ncl.edu.tw/handle/76647019350677392271

碩士 === 國立臺灣海洋大學 === 河海工程學系 === 96 === Considering the engineering safety and economy, the design discharge for water resources engineering is relied on the results of the flood frequency analysis. Since a large number of discharge records are needed in current frequency analysis methods, the methods are impracticable for watershed lacking of discharge records. For this reason, the objective of this study is to provide a suitable frequency analysis method for discharge in watershed lacking of enough hydrological records and to estimate the design discharge for agricultural water resources engineering. In this study, two flood frequency analysis schemes, namely, the index flood method coupled with L-moment method and the kinematic-wave-based geomorphologic instantaneous unit hydrograph (KW－GIUH) method using rainfall record as input, were applied to estimate the flood peak for different return periods. Hydrologic records from twenty-four watersheds in northern Taiwan were adopted to validate the proposed analytical procedure. The results indicate that the index flood method can provide accurate estimations for flood peak in low return period cases but causes apparent errors in high return period cases. On the contrary, the KW-GIUH model can have good estimations for flood peaks in high return period cases than those in low return period cases.