干旱区生态环境知识资源中心(Arid): The discovery of surface runoff in the megadunes of Badain Jaran Desert, China, and its significance

Arid

	The discovery of surface runoff in the megadunes of Badain Jaran Desert, China, and its significance
	Zhao Jingbo; Ma Yandong; Luo Xiaoqing; Yue Dapeng; Shao Tianjie; Dong Zhibao
来源期刊	Science China. Earth Sciences
ISSN	1674-7313
出版年	2017
卷号	60 期号:4 页码:707-719
英文摘要	The Badain Jaran Desert exhibits the greatest difference in altitude of all of the worlds deserts. On the slopes of megadunes in the desert, there are physical and chemical deposits produced by surface runoff. In addition, we have observed rarely-seen infiltration-excess surface runoff in the megadune depressions as well as spring streams at the base of megadunes. We used electron microscopy, energy spectrum analysis, infiltration experiments, moisture content determinations and grain-size analysis to study the mineral and chemical composition of the runoff precipitates, and grain-size of the deposits associated with the runoff, together with the hydrological balance in the megadune area, and the atmospheric precipitation mechanism responsible for groundwater recharge and for supplying water to lakes. The observations of shallow runoff and infiltration-excess surface runoff indicate the occurrence of strong and effective precipitation in summer, which would provide an important source for groundwater recharge. Several lines of evidence, such as the physical and chemical deposits resulting from shallow subsurface runoff, spring streams, infiltration-excess runoff, and gravity capillary water with a moisture content of 3-6%, demonstrate that precipitation reaches the base of the megadunes through infiltration and subsequently becomes groundwater. The chemical deposits, such as newly-formed calcite and gypsum, and gray-black physical deposits, as well as different stages in the development of fan-shaped landforms resulting from shallow subsurface runoff, indicate that groundwater recharge in the area is the result of long-term precipitation, rather than intermittent individual major rainfall events. Fine sand layers with a low infiltration capacity lead to subsurface runoff emerging at the ground surface. Five factors play an important role in maintaining a positive water balance and in replenishing groundwater via rainfall: effective rainfall as a water source, the high infiltration capacity of the sands enabling rainfall to rapidly become capillary water in the dunes, low evapotranspiration rates due to the sparse vegetation, the fact that the depth of the sand layer influenced by evaporation is shallow enough to maximize the deep infiltration of rainfall, and rapidly-moving gravity capillary water in the sandy dunes. These five factors together constitute a mechanism for groundwater recharge from rainfall, and explain the origin of the groundwater and lakes in the area. Our findings represent a significant advance in research on the hydrological cycle, including groundwater recharge conditions and recharge mechanisms, in this desert region.
英文关键词	Surface and subsurface runoff Runoff-produced physical and chemical deposits Precipitated salts and water circulation Groundwater supply mechanism Badain Jaran Desert
类型	Article
语种	英语
收录类别	CSCD
WOS研究方向	Geology
CSCD记录号	CSCD:5967600
资源类型	期刊论文
条目标识符	http://119.78.100.177/qdio/handle/2XILL650/335783
作者单位	Zhao Jingbo, College of Tourism and Environmental Science, Shaanxi Normal University, State Key Laboratory of Loess and Quaternary Geology, Xian, 710062.; Ma Yandong, College of Tourism and Environmental Science, Shaanxi Normal University, Xian, 710062.; Luo Xiaoqing, College of Tourism and Environmental Science, Shaanxi Normal University, Xian, 710062.; Yue Dapeng, College of Tourism and Environmental Science, Shaanxi Normal University, Xian, 710062.; Shao Tianjie, College of Tourism and Environmental Science, Shaanxi Normal University, Xian, 710062.; Dong Zhibao, College of Tourism and Environmental Science, Shaanxi Normal University, Xian, 710062.
推荐引用方式 GB/T 7714	Zhao Jingbo,Ma Yandong,Luo Xiaoqing,et al. The discovery of surface runoff in the megadunes of Badain Jaran Desert, China, and its significance[J],2017,60(4):707-719.
APA	Zhao Jingbo,Ma Yandong,Luo Xiaoqing,Yue Dapeng,Shao Tianjie,&Dong Zhibao.(2017).The discovery of surface runoff in the megadunes of Badain Jaran Desert, China, and its significance.Science China. Earth Sciences,60(4),707-719.
MLA	Zhao Jingbo,et al."The discovery of surface runoff in the megadunes of Badain Jaran Desert, China, and its significance".Science China. Earth Sciences 60.4(2017):707-719.