Near-surface hydrological processes in a subtropical dolomite karst slope:a field investigation from a critical zone perspective
The near-surface hydrological processes are poorly understood in karst regions,especially from the point of view of critical zone considering the vegetation-soil-epikarst system as an integrated whole.Our study illustrated this holistic view through plot-scale aboveground and underground hydrological processes investigations on a representative karst hillslope developed on dolomite in southwest China.A trench excavated to the epikarst lower boundary(depth of 4 m)made it possible for allowing identification of flow pathways and their controlling factors in the entire soil-epikarst architecture system.This system was characterized by shallow soil overlaying a highly irregular epikarst surface.The primary objectives of this study were to:(1)understand the nature and relative predominance of various near-surface hydrological processes occurring in a soil-epikarst holistic system; and(2)analyze how the integrated soil-epikarst architecture,initial moisture conditions,and rainfall intensity,affect the onset,rate,and spatio-temporal patterns of various runoff components.Runoff from the soil-epikarst system was dominated by saturated subsurface flow showing a threshold process controlled mainly by irregular epikarst surface topography.Overland flow only occurred during the high rainfall intensity events and occupied very little(ranging from 2%to 15%)of applied rainfall.Epikarst water regulation capacity was 68 mm under the wet antecedent condition and 273 mm under the dry antecedent condition,which was far more than the water regulation capacity of soil.Bedrock topography indices were more highly correlation with subsurface flow volumes than surface topography indices,indicating that bedrock surface topography exerted more evident influence on subsurface flow generation.The above results evidenced that the irregular and permeable soil-epikarst interface was a crucial component of karstic critical zone architecture and should be taken into account in the near-surface hydrological modeling for karst regions.Soil and epikarst coevolution leads to a highly connected preferential flow pathway network embedded throughout a soil-epikarst system.A complete understanding of the karst hillslope hydrological processes can only be achieved using an integrated soil-epikarst system perspective from the framework of Critical Zone science.
Hongsong Chen Zhiyong Fu Sheng Wang Jing Yang Kelin Wang
Key Laboratory of Agro-ecological Processes in Subtropical Region,Institute of Subtropical Agricultu Key Laboratory of Agro-ecological Processes in Subtropical Region,Institute of Subtropical Agricultu
国际会议
The 11th International Symposium on Geochemistry of the Earths Surface(GES-11)(第十一届地球表层地球化学国际研讨会)
贵阳
英文
1-3
2017-06-11（万方平台首次上网日期，不代表论文的发表时间）