Study Of Cross-section Analysis Methodology For Fluvial Process Based On GIS

The fluvial process is aroused by the interaction between current and riverbed, river bank as well as engineering structure. On one hand, the fluvial process can be studied by the dynamic method including mathematic model calculation and engineering structure model test; on the other hand, it also can be studied by the geomorphology method which analyses the data we measured. However, the traditional analysis of data is inefficient which can not pick up the fluvial process information fully from the channel data.The paper is to study the fluvial process based on GIS by cross-section methodology. The primary intention is to build a digital analysis methodology to reveal the procedure and law of the fluvial process based on river cross-section when the data of the lower reach of the Yangtze River are obtained and GIS analyzing methods are used. The paper includes three parts: generating cross-section half-automatically or automatically in order to provide cross-section for the analysis of fluvial process; space-time statistical analysis of cross-section to rebuild the fluvial process and thus reveal the law of it; cross-section information expression. The main achievement is:(1) From the methodology point, cross-section analysis method system is built. On the basis of application of river cross-section, cross-section analysis method is systematized, flowed, enriched, extended to utilize the channel topographical data fully and mine the rive cross-section information to the great extent.(2) From concrete problem point, analyzing the data of the Jiangsu reach of the Yangtze River, it can be concluded that the morphology of cross-section in Jiangsu Reach have a great three-level ladder situation. The paper also finds that the reach which has branches reflects the fluvial process that one branch is eroding while the other branch is silting. Moreover, the paper calculates the area and volume of the cross-section in different reach and period.(3) The paper builds the cross-section analysis methodology based on GIS platform which can be operated and systematized.The recent study's results indicate that the digitization analysis methodology is convenient and efficient and can reveal the procedure and law of the river. The technology of GIS and the fluvial process analysis can be well combined.