Application On Flow Calculation Of Debris Flow In Control Engineering By GIS Technology

It is likely to forecast that preventing the hazard of debris flow on the"5-12"earthquake-stricken area is formidable based on the experience of Song-Pan earthquake happened in 1976. The calculation of peak flow is considered to be the key parameter of control engineering in debris flow, nowadays it is generally to compute the peak flow value through the equal stream line'calculation rule which is originated from tradition hydrology, firstly the parameters of debris flow'drainage area are acquired by measuring the paper maps or digital maps manually, then, look through the hydrology handbook and follow the Drainage basin models to obtain the final peak flow value. Obviously it is complicated to carry out this procession and the working Efficiency or accuracy is difficult to certify, and last it seriously affect the designation of control engineering. In this paper, the parameters and peak flow value are obtained automatically and intelligently based on the algorithms developed in MATLAB and GIS technology; as a result, the designation of prevention engineering for disaster can be carried out in a more efficient way.The status of debris flow calculation work at home and abroad are both at the exploratory stage, in order to establish a highest accuracy DEM called Hc-DEM which can mostly reflect the true basin characteristics, the author has tested and certified 4 calculation methods to identify the best resolution of Hc-DEM in study area based on comprehensive quantitative analysis of topographic indices, and the sink fill algorithm in 3 direction is implemented in MATLAB to eliminate the paralleled rivers which the tradition method can not do. Meanwhile, this paper exploits the existing GIS spatial analysis function of the software and uses drainage density in estimating the starting point to obtain a river watersheds threshold, and the rivers which are more consistent with the actual of digital water network and related basin are successfully extracted. After the points in debris flow control works are defined, it can quickly and accurately determine the engineering point of convergence of the scope of watershed, and the main gully bed lines and it's profile can be obtained, and then follow the improved longitudinal degradation of watershed integral method to calculate the average vertical main channel bed slope, at last the required follow-up hydrological calculation parameters can be calculated in debris flow control design. In the calculation of debris flow value, combined with the actual situation, this paper determine the applicable formula for "Su-Bao River", and then make full use of MATLAB's powerful function of processing and development capabilities, design storm peak flow and debris flow peak discharge calculation of automatic algorithms , it can also be used for different debris flows.Research shows that the multi-function software and the integration algorithms can achieve fast and effective automatic acquisition of relevant parameters of debris flow and the flow of intelligent computing in the debris flow calculation of prevention works.