内蒙古孔兑区叭尔洞沟中游河谷段的风水交互侵蚀动力过程

Dynamic Process of Aeolian-fluvial Interaction Erosion in the Middle Reaches of Baerdong River in Ten-watershed,Inner Mongolia of China

本文选择内蒙古十大孔兑区的叭尔洞沟中游河谷段的观测小区开展研究,通过野外调查、气象观测、径流小区观测、地形测量和遥感监测等手段,应用"3S"技术,分析了叭尔洞沟中游河谷小区风水交互侵蚀的过程及其侵蚀产沙贡献率。研究得出:(1)在叭尔洞沟中游河谷小区,以风水两营力作用下的侵蚀量作为衡量该区侵蚀力大小的指标,在2010年,风力侵蚀量与水力侵蚀量之比约为1.8∶1。在147 794m2观测小区里,风水交互作用下侵蚀率为0.1kg.m-2。(2)风季,风力的搬运作用为观测区形成的风水交互小系统提供了输入,雨季,洪水的侵蚀作用为系统进行了输出,通过沉积物的侵蚀、搬运和堆积的循环作用,对系统的输入物质进行再分配后输出系统。(3)在1998—2010年的少风多雨时期,叭尔洞沟中游河谷小区,东岸稳定,西岸的凸岸变窄、凹岸拓宽,摆幅变大,河岸沙丘后退,切沟不断发育,水力作用在风水交互侵蚀中贡献突显。

The study area is located in the middle reaches of Baerdong River in Ten-watershed of Inner Mongolia.Field investigation,meteorological observation,runoff plot experiment,topographic survey and ＂3S＂ technology were applied to identify the dynamic process of aeolian-fluvial interaction erosion in the paper.The erosion load was used as a measurement index of the intensity of wind and water erosion.The results showed that the ratio of erosion amount made by wind and water was about 1.8∶1 and the mean erosion rate was 0.1 kg·m-2 in 2010.The wind drove the sediment into the aeolian-fluvial interaction system in the windy season,and the flood took the sediment output from the system in the rainy season.The export amount and form of sediment was influenced by the cycle process of erosion,transport and accumulation within the aeolian-fluvial interactions system.Because of little wind and much rainfall,the east bank was stable while the convex side became narrow and the concave side widened in the west bank in 1998-2010.The swing of the channel became larger,the sand dune on the river bank retreated and the gullies in the terrace continued developing.The contribution of water erosion had more impact on the aeolian-fluvial interaction.