Small watershed short-term flood forecasting method based on typical design flood hydrograph

Abstract

The invention discloses a small watershed short-term flood forecasting method based on a typical design flood hydrograph. The small watershed short-term flood forecasting method comprises the following steps: S1, obtaining design flood peak flow and the typical design flood hydrograph of a small watershed river channel in different years; s2, judging whether the riverway starts to perform short-term flood forecasting or not according to the actual measurement flow; s3, determining the forecasting time of short-term flood forecasting according to the actually measured flood flow of the riverway; s4, determining a slope Kn according to the typical design flood hydrograph of the corresponding age limit; s5, determining the predicted flood flow q'n + 1 at the moment tn + 1 according to the actually measured flood flow qn and the slope Kn at the moment tn; s6, judging whether short-term flood forecasting can be ended or not according to the actually measured flood flow at the moment tn + 1;s7, correcting the age limit Tn of the design flood hydrograph for calculating the slope Kn according to the actually measured flood flow qn + 1 at the moment tn + 1 and the predicted flood flow q'n+ 1 at the moment tn + 1; and S8, ending the short-term flood forecasting. Compared with an existing flow algorithm and a corresponding water level method, the method has the advantages of being simple, rapid and the like.

Description

technical field [0001] The invention relates to the field of flood forecasting, in particular to a small watershed short-term flood forecasting method based on a typical design flood process line. Background technique [0002] Small watersheds usually refer to small rivers and streams with a catchment area of ​​no more than several hundred square kilometers, but there is no clear limit. It is generally believed that the watershed area is 300-500 km 2 The following can be considered as small watersheds. From a hydrological point of view, small watersheds have the characteristics of mainly slope confluence, lack of hydrological data, and small catchment area. [0003] Small watershed design flood calculation is widely used in medium and small water conservancy projects, such as the construction of small reservoirs and flood skimming ditches for farmland water conservancy projects, crossing structures on canal systems such as culverts and flood gates, small bridges and culvert...

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Problems solved by technology

[0007] (4) Small-scale projects generally have a small ability to regulate floods, and the scale of the project is mainly controlled by the flood peak flow, so the requirements for the design peak flow are higher than those for the flood process line

[0011] Due to the strong empirical parameters of the hydrological method in the flow calculation method, it is difficult to accurately calibrate the parameters in the watershed with complex flow conditions; while the hydraulic method requires many different types of data and takes a long time to calculate and other shortcomings

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