A non-equilibrium sediment transport model for rill erosion

Sediment transport in rill flows exhibits the characteristics of non-equilibrium transport, and the sediment transport rate of rill flow gradually recovers along the flow direction by erosion. By employing the concept of partial equilibrium sediment transport from open channel hydraulics, a dynamic model of rill erosion on hillslopes was developed. In the model, a parameter, called the restoration coefficient of sediment transport capacity, was used to express the recovery process of sediment transport rate, which was analysed by dimensional analysis and determined from laboratory experimental data. The values of soil loss simulated by the model were in agreement with observed values. The model results showed that the length and gradient of the hillslope and rainfall intensity had different influences on rill erosion. Copyright (c) 2006 John Wiley & Sons, Ltd.

黄土高原典型小流域综合治理的水文生态效应(英文)

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56.3mm。

区域水土流失植被因子的遥感提取

NDVI是区域土壤侵蚀评价的最佳植被因子。基于遥感影像TM数据提取了NDVI值并将其与土地利用信息同时集成于土壤侵蚀图的每个图斑,建立了包含多种因子的空间数据库。通过每个图斑林草地面积百分比和NDVI值的统计分析,建立了NDVI与植被盖度的线性关系。多重因子数据库和NDVI-植被盖度关系,可以为区域土壤侵蚀定量评价提供支持。