黄土高原沟壑区小流域水土流失治理对径流的效应

THE IMPACT OF HIGH-LEVEL CONTROLLING OF SOIL AND WATER LOSS ON WATERSHED RUNOFF IN THE LOEES PLATEAU

本文用小流域平行对比观测法，分析了黄土高原沟壑区典型小流域水土保持对流域地表径流量及暴雨产流过程的影响，表明：（１）在黄土高原沟壑区，水土流失综合治理减少小流域产洪次数，降低了流域地表径流模数和径流系数，尤其以少雨年最显著；（２）使小流域地表径流模数的年际变率增大；（３）在洪水产理措施区土壤水分含量降低，根据生物气候、土壤及区域拦蓄水量特征，推测黄土高原沟壑区，以造林为主的水土保持措施拦蓄径流的作用难以使地表径流转化为地下径流或增加地下水。

In the present paper the impacts of soil and water conservation in the typical small watersheds on the gully runoff and its processes have been researched by the method of the parallel observation in the comparable two watersheds of the Loess Plateau(GPRLP).Some results are as following:The comprehensive control of soil and water loess in the GPRLP could result in that the flooding times,runoff modulus and runoff coefficient in the watershed decrease,and especially more obvious in rainfall-lack year.The yearly variation in the runoff modulus will be intensified due to watershed control.Soil moisture content under the soil and water controlling measures are lower than the compared sites.According to the basin characteristics of the bio-climate,soil and conserving runoff amount, it is presumed that although the soil and water conservation measures work well, the surface runoff cannot become into underground runoff or ground water.