Abstract:The main purpose of this paper is to introduce a semi-distributed parallel surface rainfall-runo conceptual model. In this paper, a general solution of the instantaneous unit hydrograph (IUH) has been derived successfully for N linearly connected reservoirs, each having a dierent storage constant. The solution is a function of geomorphologic parameters, meteorologic factors and roughness coecients. The model also takes into account the hydrologic response which is in¯uenced by out¯ow downstream of a reservoir. For calibration, the shued complex evolution (SCE) algorithm is used to search for the global optimal parameters of the model. Because of the parallel structure, the mean roughness parameter of the channel becomes a``conceptual'' parameter without a real physical meaning. To evaluate the adaptability of the model adopted, three watersheds around the city of Taipei in Taiwan were chosen to test the eectiveness of the model. The study provides an appropriate rainfall-runo model for planning¯ood mitigation in Taiwan.

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The main purpose of this paper is to introduce a semi‐distributed parallel surface rainfall‐runoff conceptual model. In this paper, a general solution of the instantaneous unit hydrograph (IUH) has been derived successfully for N linearly connected reservoirs, each having a different storage constant. The solution is a function of geomorphologic parameters, meteorologic factors and roughness coefficients. The model also takes into account the hydrologic response which is influenced by outflow downstream of a reservoir. For calibration, the shuffled complex evolution (SCE) algorithm is used to search for the global optimal parameters of the model. Because of the parallel structure, the mean roughness parameter of the channel becomes a “conceptual” parameter without a real physical meaning. To evaluate the adaptability of the model adopted, three watersheds around the city of Taipei in Taiwan were chosen to test the effectiveness of the model. The study provides an appropriate rainfall‐runoff model for planning flood mitigation in Taiwan. Copyright © 1999 John Wiley & Sons, Ltd.

Typhoon Morakot hit Taiwan during August 7-9, 2009. Its record-breaking rainfall caused catastrophic damage, making it the deadliest typhoon to visit Taiwan in the last 50 years. Conducting a three-months and 160-member-strong field investigation of the scale and causes of this disaster, this paper proposes strategies effective to improve flood prevention work in Taiwan. The severe flood disaster triggered by Typhoon Morakot’s excessive rainfall is attributable to four factors: (1) hydraulic system failures, (2) river flow retardation, (3) reservoir release, and (4) land subsidence. Based on these findings, this paper proposes comprehensive improvement strategies in hydraulic facility inspection, emergency response, river basin management, and climate change assessment to improve flood prevention work in Taiwan. This study combines governmental, academic, and public efforts in investigating effective post-disaster flood prevention strategies that we hope will prove to be a useful reference for other countries while facing such issues.

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