Appling the Distributed Surface-Runoff Components and a Tank Model to Establish a Rainfall-Runoff Model
| Autor: | Wei Ting Sun, 孫維廷 |
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| Rok vydání: | 2001 |
| Druh dokumentu: | 學位論文 ; thesis |
| Popis: | 89 The objective of this study was to establish a short-term rainfall-runoff model that was composed of distributed-components of the sub-watershed and the tank model. This model could reflect the characteristics of the basin geomorphology and the real structure of the stream network. Hence, this model could provide another better method to simulate the rainfall-runoff of upland watersheds. Here the method to estimate the amount of infiltration adopted the method developed by Soil Conservation Service (SCS) for computing the abstraction from rainfall. That was to separate the rainfall into infiltration and excess rainfall. Then input the infiltration and excess rainfall into the tank model and the direct runoff model respectively. Furthermore, the tank model was used to simulate the process of the infiltration transferred into the baseflow and could avoid the uncertainty of the mechanized procedure of the base-flow separation. As for the direct runoff model, a watershed can be treated as a number of subwatersheds based on the stream network. The digital terrain model (DTM) and the ARC/INFO software of Geographic Information System (GIS) were used to product the stream frame and demarcate subwatersheds. Furthermore, SCS dimensionless hydrograph and S-hydrograph methods were used to evaluate the five minutes duration of each distributed-component’s unit hydrograph. According to the space position of each subwatersheds and stream frame, the Muskingum-Cunge method developed by Cunge(1969) was applied to hydrologic river routing and simulate direct runoff hydrologic for the watershed. As for the process of the infiltration transferred into the baseflow, the two connected conceptual tanks were employed in this model to simulated the interflow and baseflow. In this study, the model was applied to simulate the runoff of the typhoon events in the Xiu-Loan upstream watershed of the Sh-men reservoir in Taiwan. During the Herb and Zeb typhoons, the river scoured or deposited so that the rating curve would be change. Therefore, the runoff coefficient was used to recheck the rating curve. The simulated results of Yancy, Polly, Omar, Ted, Herb, Winnie and Zeb were very satisfied with observated runoff when the rainfall intensity was high. Besides, another method adopted in this study was unit hydrograph and tank model and its simulated results also showed closely with previous model’s. But when rainfall intensity was small, the observed runoff coefficient was low. Hence, the model should be improved to simulate interception, depression storage and evaportranspiration in the further. |
| Databáze: | Networked Digital Library of Theses & Dissertations |
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