Analysis and Prediction of Gravity Erosion in Typical Small Watershed in the Fifthsub-region of Huangtu Hilly Area
GAO Zhe;ZHANG Fu;GAO Jianen;ZHAO Chuanyan;ZHANG Hongkui;QI Jiyang;BAI Yuqi;LI Xiaoya;The College of Forestry in Gansu Agricultural University;Institute of Soil and Water Conservation,Northwest A&F University;Institute of Soil and Water Conservation,CAS & MWR;College of Pastoral Agriculture Science and Technology,Lanzhou University;NingXia Green FengYuan Engineering Consulting Co.Ltd.;Department of Geography,Dingxi Teachers College;
This paper aimed at the problem that the calculation of siltation amount of silt dam caused by gravity erosion because of gully bank collapse and slope collapse during the operation of 5 th sub-region silt dam on the Loess Plateau.By the method of actual measurement and 3 Stechnique generation and original design of reservoir capacity curve,the silt blocking amount and soil erosion mode of silt dam during running period were checked and analyzed.The results showed that,(1)The morphological discriminant coefficient(α'),which reflects the silt form of silt dam,is between 0.711 and 208.517,and the mean value is 48.238.it indicated that the other silt dams were Delta deposition except Yangshan,which were the Vertebral siltation because the critical number were less than 2.2;(2)The shape parameters of dam controlling area,such as area of silt surface,circumference,silt volume and discriminant coefficient of silt form,had great influence on gravity erosion.The calculation relation of gravity erosion amount and erosion modulus were given;(3)The range of the modulus of gravity erosion is 184.79~812.80 t/(km~2·a),the mean value is 360.68 t/(km~2·a),and the range of modulus of siltation and sediment production in dam controlling area was 225~2 719 t/(km~2·a),with a mean value of 1 382 t/(km~2·a).The modulus of gravity erosion accounts for26.1% of the modulus of sediment production.The above results showed that the reservoir sediment came from the hydraulic erosion and the gravity erosion of the reservoir area in the 5 th sub-region of the Loess Plateau.The operation and management of the silt dam should prevent the gravity erosion from destroying the existing cultivated landand silt of channel base floweroded dam land.These could result in the silt dam being not able to be used efficiently.
【Fund】： 陕西省自然科学基础研究计划重大基础研究项目(2016ZDJC-20);; 国家自然科学基金项目(41571051)
【CateGory Index】： S157.1
【CateGory Index】： S157.1