黄土丘陵区近十年来典型流域侵蚀环境演变的泥沙响应

In resent decade, the total amount sediment in the Yellow River fell sharply, and the quantitative identification about the contribution of natural and human activities to the water resources and sediment of the Yellow River became a hot scientific topic. For the implementation effect of the project of "Grain for Green" from 2003 to 2012 is obvious, this project chooses a small representative watershed in the Loess Hilly region to study coupling relationship between the total quantity, the annual variance and the origin of the sediment, and ecological environment recovery. The objective of this research is to reverse the mechanism of the sediment response of the erosion environmental change that based on the project of " Grain for Green", to elucidate the law of the erosion environmental evolution of the small watershed in Loess Hilly and gully region in the past decade, to explain the contribution to the variation of erosion environmental and water and sediment of the Yellow River scientifically, and predict the trend of the coupling relationship between natural and human activities. The results will provide a theoretical basis for the construction of ecological environment in the Loess Plateau, the management of the health of the Yellow River, and the evaluation of ecological construction in the Loess Plateau. Besides, it will support the research of the response of Yellow River water and sediment variation for the erosion environmental evolution in the Loess Plateau.

该项研究针对近年来黄河泥沙的锐减现状以及定量判别自然和人类活动对黄河水沙的贡献等热点科学问题，以2003-2012年国家退耕还林工程实施效果的显现期为背景，采用典型流域剖析的方法，深入研究近十年以来黄土丘陵区典型流域侵蚀泥沙总量、年际变化量以及来源与生态环境恢复的耦合关系，旨在反演退耕还林还草工程背景下侵蚀环境演变的泥沙响应机制，阐明近十年来黄土丘陵沟壑小流域土壤侵蚀环境演变规律，科学回答自然、人类活动耦合作用对该区侵蚀环境演变、水沙变化的贡献及发展趋势。研究结果可为黄土高原生态环境建设与黄河健康管理以及"黄河水沙变化对黄土高原侵蚀环境演变过程的响应研究"提供重要科学支持，同时为黄土高原生态建设工程实施效果评估提供支撑。

该项研究针对近年来黄河泥沙的锐减现状以及定量判别自然和人类活动对黄河水沙的贡献等热点科学问题，以2003-2012年国家退耕还林工程实施效果的显现期为背景，采用典型流域剖析的方法，通过淤地坝沉积泥沙剖面沉积旋回和小流域侵蚀性降雨对应关系的分析，对小流域近十年的土壤侵蚀模数进行了计算；同时利用遥感手段分析了小流域相应年的植被变化情况，并对植被恢复过程中的小流域的土壤侵蚀变化进行了分析，明确了两者之间的关系；进一步利用复合指纹识别技术探索研究了小流域侵蚀泥沙的来源。结果表明：在年尺度上，小流域年平均NDVI的平均值0.61，整体上呈现增加趋势，说明植被覆盖增加，生态环境好转；小流域9年的泥沙侵蚀总量为6063.91 t，而侵蚀模数9年平均值为137.04 t/km2•a，下降至小流域综合治理工程实施前的2.3%，平均年下降率10.86%；在植被重建的作用下，小流域的侵蚀现状降低至轻度侵蚀的水平；且其侵蚀泥沙主要来源于支沟道。研究结果可为黄土高原生态环境建设与黄河健康管理以及"黄河水沙变化对黄土高原侵蚀环境演变过程的响应研究"提供重要科学支持，同时为黄土高原生态建设工程实施效果评估提供支撑。