GIS支持下岷江上游水文特征空间分析

Spatial Analysis of Hydrological Characteristics of the Upper Reaches of Minjiang River Based on GIS Technology

流域水文特征的提取与分析不仅为水文过程模拟提供重要参数,而且是研究水土流失和制定防洪减灾措施的基础依据。以岷江上游90 m分辨率的DEM数据为基础,利用GIS手段提取了分水岭、流域面积以及河流长度等河网基本信息,并对流域内的干流和主要支流的河网密度、河道纵剖面等特征进行了定量分析。又据1982-1987年间岷江上游地区的21个雨量站的降水资料和同时期8个水文站的逐年径流量数据,对该流域及其主要子流域的径流系数进行了计算。结果表明：岷江上游流域的平均径流系数为0.77,各子流域的径流系数从北面镇江关流域的0.55递增至南面姜射坝水文站以下流域的0.88。流域的河网密度为0.172 km/km2,其各子流域变化范围为0.165~0.177 km/km2。干流河道平均比降为9.7‰,自北向南分布的5条支流的纵剖面凹曲度和比降均呈增加趋势,且主河道剖面形态受构造运动影响显著。

Hydrological characteristics are not only the basis for water cycle and soil erosion research,but also can provide beneficial support to avoid geological and flood hazards.This research extracted river network information and watershed of upper Minjiang River Basin by GIS tools from digital evaluation model（DEM） with 90 m resolution,and analyzed drainage system density,longitudinal channel profiles of main channel and major tributaries quantitatively.Then we calculated runoff coefficient of the drainage basin from precipitation data of 21 rain-gauge station and runoff data of 8 hydrological station of upper Minjiang area from 1982 to 1987.The results indicate that： the runoff coefficient of Zhenjiangguan basin is the least one among all sub-basins,which is 0.55,the basin from Jiangsheba to Zipingpu hydrological station is the biggest one,which is 0.88,and the whole upper Minjiang River Basin is 0.77.The drainage density of upper reaches of Minjiang River is 0.172 km/km2,all sub-basin＇s drainage densities are between 0.165 and 0.177 km/km2.The channel slope of main stream is 9.7‰,the concave of longitudinal channel profiles and channel slope of the five tributaries which scatter from north to south in upper Minjiang River Basin decrease one after another,and main stream profile is affected by tectonic movement significantly.