基于GIS的目平湖泥沙冲淤变化空间定量分析

GIS-based spatial quantitative analysis on change of sediment deposition and erosion in Muping Lake

针对洞庭湖泥沙研究大多基于物理与数学方法的现状,为实现泥沙冲淤变化的空间定位与可视化,基于GIS的空间数据处理与空间分析,提出泥沙冲淤变化空间定量计算与分析的综合方法。其步骤是:通过收集水下地形数据,建立数字高程模型;根据不同时间的高程模型计算容积及其变化;对冲淤区域进行空间划分,计算各区域冲淤量;总结泥沙冲淤的总体与局部规律。选择西洞庭目平湖,运用该方法,定量计算其库容,分析湖底地形变化情况,对冲淤变化区域进行空间划分,最后分析并总结其冲淤变化规律。研究结果表明:目平湖约85.42%处于淤积状态,少部分处于冲刷状态,北部淤积现象较严重,泥沙淤积由北向南、由西向东减少。

Nowadays, most researches about Dongting Lake＇s sediment are based on physical or mathematical method, an integrative method based on spatial data processing and analysis of geographical information system （GIS） software was put forward for spatial quantitative calculation and analysis on the change of sediment deposition and erosion, and for its spatial positioning and visualization. The steps of this method are as follows： collect under-water topographical data and create digital elevation model （DEM）, calculate volume of DEM at different time and the change of their volume, classify the deposition and the erosion regions spatially and calculate the volume of deposition or erosion of every region, and then summarize the holistic and the local rule of sediment deposition and erosion. By using this method, the volume and the change of under-water terrain of Muping Lake, in the west Dongting Lake, China, were calculated quantitatively, and the under-water changing regions of sediment deposition and erosion were classified spatially, and the change rules of sediment deposition and erosion of Muping Lake were analyzed and summarized. The results show that about 85.42%, of Muping Lake is in sediment deposition, and the others are in erosion; more thicker deposition is in the north, and the deposition decreases from north to south, and from west to east.