【摘要】 淤地坝是黄土丘陵区小流域水土流失治理的重要工程措施之一,在拦蓄泥沙的同时,也记载了小流域侵蚀产沙的历史变化过程及特征。该研究根据流域历史降雨资料,分析了黄土丘陵区关地沟小流域淤地坝1959～1987年泥沙沉积旋回变化及各旋回层泥沙中、小流域沟间地和沟谷地表层土体中放射性同位素137Cs含量,研究了小流域侵蚀产沙变化过程及泥沙主要来源。结果表明:该小流域在淤地坝建设初期,侵蚀产沙强度很大,其后产沙强度由强变弱,呈显著降低趋势,淤地坝内沉积泥沙的70%来源于沟间地;微小流域与较大流域在泥沙来源方面存在较大差异。更多还原

【Abstract】 In Loess Hilly Region,as one of the most important engineering measures for controlling soil and water losses,silt dams play an important role for reducing sediments and recording the historical variation process and characteristics of sedimentation in a small watershed.Combined with the history rainfall events and 137Cs contents of the silt dam and the surface soil samples of the inter-gully area and the gully side,sediment deposition cycle changes during the period 1959~1987 were analyzed.The sedimentation variation process and the sediment sources were studied in Guandigou watershed in Loess Hilly Region.The results show that in the initial stage of the silt dam construction,the sedimentation is very strong and then reduces greatly.The inter-gully area is the main sediment source area,which accounts for 70% of the total deposited sediment.There is great difference in sediment source between large watersheds and small watersheds.更多还原