A Study of Rivers Hydraulic Routing Combined with Rainfall-Runoff Model

• Main Authors: Yu-Te Su, 蘇祐德
• Other Authors: I Tsou
• Format: Others
• Language: zh-TW
• Published: 2007
• Online Access: http://ndltd.ncl.edu.tw/handle/00037937801295495173

碩士 === 國立屏東科技大學 === 土木工程系所 === 95 === The study worked on rainfall-runoff model, HEC-HMS, to simulate Dong-gang River watershed. The watershed was divided into 16 major sub basins to carry on the simulation. The precipitation data was allocated to each sub basin by Thiessen method, and transformed into runoff hydrograph by Snyder’s unit hydrograph method in HEC-HMS. The runoff hydrograph of each sub basin would be the input of unsteady one-dimension channel routing in HEC_RAS. The results from HEC-RAS, such as overflow volume, flooding area and flooding depth, would be calculated and demonstrated by ARC GIS. The results show that the seven typhoon events are quite match with the simulated results from rainfall-runoff model. The average error of peak flow discharge was close to 2.04%, the average error of total flow discharge was about 3.73%, and the peak flow arrived time was within one hour from observation data. Therefore, the rainfall-runoff model combined with unsteady one-dimension hydraulic model can be applied to storm simulation in Dong-gang River properly. The results from the river routing also show that overflow would happen at middle and down stream of Dong-gang River, especially at cross-section No.19 and No.38 The overflow estimation by the first approach in this study show that, during the Typhoon Bilis, the flood area and depth near by cross-section No. 19 was about 7393600 m2 and 11.3 cm respectively for ground level under 10 m, and the flood area and depth near by cross-section No. 38 was about 1152000 m2 and 68.6 cm respectively for ground level under 14 m. The second overflow estimation approach applied on 0612 flood event show that flood depth was 90 cm and 70 cm for the flood detention area near by cross-section No.13 and 29 correspondingly. Those results are close to the data from the report of 0612 flood event investigation, which are 50~120 cm and 60~70cm correspondingly. That conclude using side weir and storage area module to simulate flood area and depth are practicable.