A Method for Obtaining Watershed Unit Lines Using Complete Two-Dimensional Shallow Water Equations

Abstract

The invention discloses a method for obtaining drain basin unit lines by utilizing complete two-dimensional shallow water equation sets. According to the method, a hydrological problem is solved by utilizing a hydrodynamic way. The method comprises the following steps of: firstly discretizing a two-dimensional shallow water equation set to establish a high-resolution two-dimensional shallow watermathematic model, so as to ensure that the two-dimensional shallow water model is capable of correctly simulating slope runoff processes; carrying out elevation assignment and roughness factor assignment by adoption of a triangular unstructured grid division calculation area; in order to avoid the problem of non-conservative drainage basin outlet water yield caused by drainage basin depression impounding, setting continuous time interval net rainfall processes as model input conditions; setting a drainage basin outlet as a free falling outflow condition; carrying out two-dimensional shallow water mathematic model calculation after setting a drainage basin initial state; after the calculation is ended, enabling a flow process at the drainage basin outlet as an S curve of the drainage basin;and obtaining a time interval unit line of the drainage basin by utilizing a conversion formula. The method is capable of covering the shortages of existing hydrological methods, and providing a newway for flood confluence analysis and calculation of regions without hydrological data.

Description

technical field [0001] The invention belongs to the technical field of water conservancy engineering, in particular to a method for obtaining a river basin unit line by using a complete two-dimensional shallow water equation group. Background technique [0002] The so-called unit line refers to the flow process line formed by the unit net rainfall evenly distributed on the watershed in a unit period of time at the outlet section of the watershed. The unit line method is one of the most commonly used methods for the calculation of watershed flow. In traditional business applications, analysis and trial-and-error methods are often used to calculate the unit line of a watershed. The application of these methods requires a prerequisite, that is, the watershed has sufficient measured rainfall and runoff data. However, in most small and medium watersheds in my country, there is no sufficient rainfall runoff data. [0003] At present, my country is currently carrying out mountain ...

AI Technical Summary

Problems solved by technology

This method still has good applicability in areas without data, and overcomes the problem that the unit line confluence calculation method is difficult to use due to the lack of hydrological data in small and medium watersheds.

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