Calculation And Evaluation Of The Amount Of The Riverbed Erosion And Deposition Based On DEM

The calculation and analysis of the amount of riverbed erosion and deposition has important scientific and practical significance that is a basic work for the scientific experiments, the water conservancy project construction and the prediction of riverbed evolution. The traditional method of calculation and analysis which based on the measured data is low calculation precision and it can’t give detailed distribution of river sediment. GIS has powerful abilities of spatial analysis and map expression. DEM technique is introduced to not only enhance spatial analysis ability of the GIS, but also directly reflect the topographic relief of the area. It just overcomes the defect of the traditional method of calculation and analysis.In this paper, we take the riverbed from the section Lijin(3) to Qing-3 as an example, and chose eight periods of the data of the area which respectively measured in April 2004, October 2004, April 2006, October 2006, April 2008, October 2008, April 2010 and October 2010. We respectively build the grid DEM of the riverbed based on the ArcGIS and the Surfer, and calculate the amount of erosion and deposition and tank storage of the riverbed, and compare the calculating results of the two methods. The main conclusions are as follows.1) What the method build the riverbed grid DEM based on the measured data of the section is proposed. By the analysis of the characteristics of the riverbed landform and the measured data in the study area, we paint the riverbed interpolation line, and interpolate the riverbed elevation point along the interpolation line. And by using ArcGIS Engine technique, we program to realize the importing of the section measured point data and the generating of the elevation point, and build the high quality DEM data of the riverbed.2) Calculated results of the study area based on the ArcGIS and the Surfer has the same plus or minus at the same time, it indicates that the results the two methods of calculation show the same character of the riverbed erosion or deposition at the same time. Because of the principle of the two methods of DEM volume calculation is different, which causes the different amount according to the same measured data, but the trend is the same size.3) After began to implement the scheduling of water and sediment of the Yellow River, the riverbed in the study area is erosion state as a whole in April to October every year. But the erosion quantity is very difference in different years. The riverbed in the study area is silting state as a whole in every October to the following year April. The total erosion quantity is greater than the total sediment deposition in the study area in a full one-year period. It keeps in line with the actual erosion and deposition of the riverbed in the study area, this shows that the method used herein is reliable.