黄土高原典型小流域综合治理的水文生态效应

从流域产流规律及水土保持措施改变引起的土壤水分状况和流域蒸散发的变化等方面评价了黄土丘陵沟壑区泉家沟流域水土保持措施变化对流域水分生态环境的影响.结果表明:水土保持与生态建设过程改变了土地利用结构,对小流域水环境变迁具有很大的影响作用,主要表现在:减少地表径流量,径流模数1996～2000年平均较1980～1985年减少了36.1%;不同治理措施土壤水分状况不同,灌木林地、人工草地和乔木林地均存在深度和厚度不等的土壤"干层";不同地貌部位土壤储水差异很大,阴坡的水分环境优于阳坡,沟底优于峁顶,缓坡优于陡坡;林草措施对流域总蒸散量起着决定性作用,1991～1995年流域林草地面积达到最大,总蒸散量也达到最大,与治理初期相比,总蒸散量累计增加了56.3 mm.

Hydrological and environmental responses to comprehensive control of soil loss in a typical watershed of hill and gully region of the Loess Plateau

Certain aspects of hydrological and environmental response to conservation practices and land use pattern changes in the Quanjiagou watershed in the hilly and gully loess area were assessed, such as runoff, dynamics of soil moisture and evaportranspiration. The results showed that soil-water conservation practices and ecological construction had significant influence on the hydrological and environmental processes of the watershed. Surface runoff was decreased by 36.1% from 1980 to 2000. Soil moisture status varied greatly with different erosion control practices: shrub land, grassland and timber forestland all had "dry layer" in the soil profile with different thicknesses and depths. There existed great differences in soil water storages with different landform position. The north-facing slopes had better hydrological environment in the soil than the south-facing slopes, and gully bottoms were better than hilltops and gentle slopes, better than steep slopes. Forest and grass practices played a decisive role in evapotranspiration. The total evapotranspiration reached a maximum in 1991-1995, and cumulative evapotranspiration increased by 56.3mm compared to the start of erosion control.