Determination of groundwater recharge mechanisms using stable isotopes in small watersheds of the Loess Plateau, China
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Determination of groundwater recharge mechanisms using stable isotopes in small watersheds of the Loess Plateau, China Jianye Ma 1 & Zhanbin Li 1 & Bo Ma 1 & Baoyang Sun 2 & Junbo Xiao 3 & Chenguang Liu 1 Received: 30 March 2020 / Accepted: 5 October 2020 # Springer-Verlag GmbH Germany, part of Springer Nature 2020
Abstract Water sustainability is a major challenge on the Loess Plateau of China, since the drying of soil and loss of surface water is threatening regional water security. Fundamental to effective water management is an understanding of groundwater recharge mechanisms. Based on a time series of stable isotopes data for precipitation, surface water and groundwater, the groundwater recharge ratios and water transmission times were quantitatively identified for the studied region. The results showed that groundwater discharge to surface water was a common phenomenon during the dry and wet seasons. However, groundwater could also be recharged by precipitation and surface water during specific months when experiencing large precipitation events. Over shorter time scales (1 year), precipitation was the primary recharge source of groundwater in small watersheds due to the general flow direction of groundwater to surface water. Groundwater recharge by precipitation mostly occurred through a combination of piston flow and preferential flow, where preferential flow was the primary recharge mechanism for groundwater replenished by precipitation in this region. Surface water could quickly recharge groundwater by lateral flow through fractures in the aquifer and vertical piston flow. These findings could, therefore, be used to provide a reference for the utilization and protection of groundwater resources in the small watersheds of the loess hilly regions of the Loess Plateau. Keywords China . Stable isotopes . Groundwater recharge . Water transmission time . Small watershed
Introduction Groundwater is critical for regulating the hydrological cycle and sustaining ecosystem health in arid and semiarid regions (Scanlon et al. 2006). Shallow groundwater may be able to sustain a vibrant ecosystem directly by providing a stable source of water for vegetation (Yao et al. 2018). However, the role of groundwater in terrestrial ecohydrological systems * Zhanbin Li [email protected] 1
State Key Laboratory of Soil Erosion and Dryland Farming on the Loess Plateau, Institute of Soil and Water Conservation, Northwest A&F University, Yangling 712100, China
2
Changjiang River Scientific Research Institute of Changjiang Water Resources Commission, Wuhan 430000, China
3
Guangxi Zhuang Autonomous Region Water Conservancy and Hydropower Investigation and Design Institute, Nanning 530000, China
is poorly understood (Change 2007). The groundwater level and recharge state, therefore, become important indicators in the analysis of the ecological state of arid and semiarid regions (Eamus and Froend 2006); however, this information is difficult to obtain in those regions, with relatively low infiltration rates and commonly th
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