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(一) 基本情况黄河中游龙羊峽至桃花峪土地总面积60.7万平方公里,包括陝西、甘肃、山西、內蒙、青海、河南、宁夏七省(区)的256个县(旗、市)的全部或大部,共有耕地2亿亩,人口4,253万,其中农業人口3,566万。区内大部为黄土复盖,土壤疏松,丘陵起伏,坡陡溝深,根据典型与量图計算,共有一公里以上的溝道32万余条,其中1～5公里長溝道二七万一千余条,6～10公里長溝道四万七千余条,11～50公里长溝道二千三百余条,50公里以上者一百八十余条。同时,植被不良,暴雨集中,虽然年降雨量仅200～600公里,但是多集中在7～9月以暴雨形式出現;加以过
(I) Basic Information The total land area of Longyangxia to Taohuayu in the middle reaches of the Yellow River is 607,000 square kilometers, including 256 counties (banners and cities) in Shaanxi, Gansu, Shanxi, Inner Mongolia, Qinghai, Henan and Ningxia All or most, a total of 200 million mu of arable land, population 42.53 million, of which agricultural population of 35.66 million. Most of the area is covered with loess, with loose soil, hilly hills and steep slopes. According to the calculation of typical and quantitative maps, there are more than 320,000 trenches of more than one kilometer, of which 1 to 5 kilometers of long trenches are 27,000 More than a thousand, 6 to 10 km long channel more than 4700, 11 to 50 km long channel more than 2,300, 50 kilometers more than 180 articles. At the same time, poor vegetation and heavy rain concentrated, although the annual rainfall is only 200 ~ 600 km, but more concentrated in July-September in the form of heavy rain; to be over