title: Determination of groundwater recharge mechanism in the deep loessial unsaturated zone by environmental tracers.
abstract: Studying the groundwater recharge mechanism in regions with thick unsaturated zone can greatly improve our understanding of hydrological processes since these regions have complex groundwater processes. This study attempted to discuss the groundwater recharge in a region covered by loess over 130m deep in China's Loess Plateau. The water stable isotope, tritium and chloride in precipitation, groundwater and soil water were determined and used as inputs of mass balance methods. The tracer technique is found to be applicable and effective this region with thick unsaturated zone. The groundwater originates from rapid precipitation infiltration through some fast flow paths. The total recharge is likely to be 107±55mmyr-1accounting for 19±10% of average annual precipitation, while the recharge from preferential flow accounts for 87±4% of the total recharge. The identified recharge mechanism has important implication to groundwater management and recharge modeling for regions covered by thick loess.
authors.affiliation: State Key Laboratory of Soil Erosion and Dryland Farming on the Loess Plateau, College of Natural Resources and Environment, Northwest A&F University, Yangling Shaanxi 712100, China. Electronic address: lizhibox@nwsuaf.edu.cn.
authors.forename: Zhi
authors.initials: Z
authors.lastname: Li
authors.affiliation: State Key Laboratory of Soil Erosion and Dryland Farming on the Loess Plateau, College of Natural Resources and Environment, Northwest A&F University, Yangling Shaanxi 712100, China.
authors.forename: Xi
authors.initials: X
authors.lastname: Chen
authors.affiliation: State Key Laboratory of Soil Erosion and Dryland Farming on the Loess Plateau, College of Natural Resources and Environment, Northwest A&F University, Yangling Shaanxi 712100, China.
authors.forename: Wenzhao
authors.initials: W
authors.lastname: Liu
authors.affiliation: State Key Laboratory of Soil Erosion and Dryland Farming on the Loess Plateau, College of Natural Resources and Environment, Northwest A&F University, Yangling Shaanxi 712100, China; Department of Soil Science, University of Saskatchewan, Saskatoon, SK S7N 5A8, Canada. Electronic address: bing.si@usask.ca.
authors.forename: Bingcheng
authors.initials: B
authors.lastname: Si
keywords: Environmental tracers; Loess Plateau; Mass balance method; Recharge mechanism; Soil water movement