Up to present, relative river planning analysis models have been proposed by the cooperation with domestic academic institutions. However, few foreign models, such as CCHE, SRH, RESED, GNeSIM, and GLMRT, are introduced into Taiwan as well. On the other hand, the central river analysis system developed by water resources planning institute plays a vital role in Taiwan, which are mainly used by related authorities and academic institutions. Nevertheless, the differences in implementation between each model, especially the interfaces of pre-processing and post-processing, may increase the difficulty in model coupling. The Hydraulic Numerical Models Platform, therefore, is being developed in order to preliminary integrate each model and expand the capability of those models.
Brief introduction of each model：
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CCHE：
CCHE was developed by the United States National water science and Engineering Center (National Center for Computational Hydroscience and Engineering, NCCHE), University of Mississippi, which has engaged in the development of advanced numerical models for watershed processes, channel network hydraulics, river morphology, flood analysis, irregular wave deformation etc. It has been applied to the problems of rivers and coasts in the United States and other countries. For example, the simulation of turbulent flow is demonstrated in Figure 1.
Figure.1 Simulation of turbulent flows in natural channels with many river training spur dikes.
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SRH：
SRH, Sedimentation and River Hydraulics, is a flow hydraulic and mobile-bed sediment transport model for river systems, including SRH-1D, SRH-2D, and SRH-3D. It has been developed at the U.S. Bureau of Reclamation. As shown in Figure 2, the bridge scouring problem can be simulated as an evaluation of new bridge construction.
Figure.2 Evaluation of Bridge Scour
Since 2006, Technical Assistance and Cooperation under Appendix No. 8 to the Agreement between TECRO and AIT for Water Resources have been carried out which have been executed through the U.S. Bureau of Reclamation (Reclamation) and the Taiwan Water Resources Agency (WRA). In respond to Taiwan’s geologic setting and high annual precipitation, a series of SRH modules have been developed, including soft bedrock erosion, riverbank erosion, reservoir turbidity current etc.
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RESED：
RESED, including RESED-2D and RESED-3D, was initially invented by Dr. Hsieh(2002) and has been developed at National Chiao Tung University for the simulation of two-dimensional flow analysis, pollutant transportation, and sediment transportation.
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GNeSIM：
GNeSIM (Nested Storage-based Inundation Mapping model for over-leeve flooding) has been applied to rapidly assess the inundation area and water-depth during the flood event.
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GLMRT：
GLMRT is a two-dimensional shallow water wave model, which is applicable to dam break flow with the flat and wet bed conditions in both upstream and downstream, developed by Dr.Tsai using Lattice Boltzmann Method.
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Central River Hydraulic Analysis System：
The digital elevation model of the watershed in 26 central rivers in Taiwan had been established in the period of 2000 to 2004. Furthermore, in 2005, the function of watershed precipitation analysis and discharge of different return periods was included. Up to now, the coupling of the system and HEC-RAS module are capable of analyzing the overbank flow and inundation mapping.