南水北调中线总干渠沿线水文气候特性分析

Analysis on hydroclimatic characteristics along the main canal of Middle Route Project of S-N Water Transfer

南水北调中线工程总干渠沿线纵贯江、淮、黄、海 4大水系 ,穿越大小河流 6 5 0余条 ,控制交叉河流集水面积 90余万平方公里 ,影响供水范围约 15万km2 ,其水文气候特性复杂。在大量统计总干渠沿线河流及地区的水文气候资料基础上 ,分析了总干渠沿线的气候、暴雨洪水、泥沙的变化及地区分布规律 ,并初步分析了沿线大型水利工程调洪拦沙影响。中线工程沿线多年平均降雨 5 0 0～ 90 0mm ,并具有从南向北 ,从山区向平原及山间盆地递减趋势。总干渠沿线为暴雨洪水多发区 ,洪水发生时间多集中在 6～ 8月 ,一次洪水历时一般 3～ 7d ,洪水洪量集中 ,3d洪量可占 7d洪量的 80 %。泥沙侵蚀模数在 2 0 0t/(km2 ·a)以上 ,最高可达 2 5 0 0t/(km2 ·a)。总干渠沿线兴建了众多大、中、小型水库 。

The general canal of Middle Route Project of S-N Water Transfer passes through 650-odd rivers in 4 river system of Yangtze river,Huaihe river,Yellow river and Haihe river and the total drainage area of the rivers crossed with the canal reaches more than 0.9 million km\+2 and the influencing water supply area is about 150 thousand km\+2.The hydroclimatic characteristics in these areas are complicated.On the base of enormous data of hydroclimate,this paper analyses the variation and regional distribution of climate,storm flood and sediment as well as sediment retaining effect of large water conservancy projects of the canal crossing rivers.The mean annual precipitation along the Middle Route Project is 500～900 mm and characterizes successive decreasing tendency from south to north and from mountainous area to plain area and intermountainous basin.Along the general canal it is a storm prone area and floods mainly concentrate in June to August.The duration time of flood is generally 3～7 days.The flood volume is so concentrated that the flood volume in 3 days can reach 80% of a 7-day flood volume.The sediment erosion modulus is above 200 t/(km\+2·a) with maximum of 2 500 t/(km\+2·a).A large number of reservoirs along the general canal crossing rivers in various scale have been constructed and possess significant role of flood regulation,flood peak reduction and retention.