黄土高原沟壑丘陵区沟道侵蚀与洞穴侵蚀特征

目的]通过对黄土高原沟壑丘陵区内的沟道侵蚀和洞穴侵蚀进行特征分析,为该地区开展水土保持工作提供数据支持和决策依据。方法]以王家沟流域为研究对象,通过资料收集、卫星影像识别和现场调查等方法对流域内沟道侵蚀和洞穴侵蚀状况进行分析。结果](1)流域内共分布718条沟道和948个洞穴。(2)根据空间位置和地形特点将所有沟道分为冲沟、切沟、干沟、河沟。这4类沟道由于受土壤岩性组成、坡度及人为活动等因素影响,空间分布存在巨大差异。(3)43%的洞穴分布在冲沟中,51%分布在切沟中,6%分布在干沟中。河沟中没有洞穴存在。冲沟和切沟是洞穴形成和发育的主要区域。(4)洞穴沟道的沟长、面积、切深、产流及产沙量都明显大于非洞穴沟道。结论]在黄土高原丘陵沟壑区,洞穴侵蚀是土壤侵蚀的重要组成部分,并对沟道的发育和扩展起着至关重要的作用。

Features on Gully Erosion and Tunnel Erosion in Loess Hilly and Gully Region

Objective] In order to give effective data and decision supports for soil and water conservation work, this article ananlyzed the features of gully and tunnel erosion in the loess hilly and gully region of Northern China;Methods] The present study was carried out in the Wangjiagou watershed and through historical materials, aerial photo interpretation and field investigations;Results] (1) A total of 718 gullies and 948 tunnels are indentified in the study watershed. (2) On the basis of their location and topography, all the gullies are classfied into four types:headwater gully, hillside gully, valleyside gully and ephemeral river gully. Intricately affected by lithological composition, slope, human activities, etc, the four types gullies have significant variables in the spatial distribution. (3) Tunnels are associated with 43% of headwater gullies, 51% of hillside gullies, 6% of valleyside gullies and none of ephemeral river gullies. The headwater gullies and hillside gullies are the main area for development of tunnels.(4) The results show that statistically significant differences exist in gully length, area, cutting depth, runoff yield, and sediment yield of tunneled gullies are significantly greater than those of untunneled gullies;Conclusion] The stuty suggest that soil erosion is dominnated by tunnel erosion, and gullies development is intricately affected by tunnel erosion in this area.