Mathematical modelling of flow in fishway at river hydroelectric power plant

摘要

My graduation thesis deals with mathematical modelling of the flow in a fishway at a river hydroelectric power plant with 1D model HEC-RAS, and 2D models MIKE 21 and PCFLOW2D. In the first part of the thesis, data on various types of fishways and speed limits are presented. Fish population using the fishway for upstream and downstream migration and their swimming parameters are described in continuation. Migratory fish are divided in those migrating at shorter and longer distances. The analysis results are length, age and density of fish population, which is the stating point for defining biological criteria for dimensioning a fishway. In the second part, a flow is simulated in some selected types of fishways with different arrangement of obstructions, and their comparison is made. Then, a detailed description and elaboration of mathematical models for 1D and 2D flows are given. Basic equations and input parameters used for calculation are given for each model separately. The stated models are based on the results obtained in the first part of my thesis. To ensure corresponding hydraulic conditions, various types of obstructions are inserted in the models which are described in details. Types which favourably influence in the origin of static water zones have especially been considered. When determining the obstructions, different examples of existing fishways have been taken into account. Hydraulic calculation is done for 1D and 2D flows. A hydraulic model is done by means of HEC-RAS, MIKE 21 and PCFLOW2D programs. Based on the results of mathematical modelling, possible shapes and dimensions of obstructions in pools are shown. Finally, comparison between the 1D and 2D models, and compliance of the conditions in fishways for different kinds of fish are stated.