Regional aridity is increasing under global climate change,and therefore the sustainable use of water resources has drawn attention from scientists and the public.Land-use changes can have a significant impact on grou...Regional aridity is increasing under global climate change,and therefore the sustainable use of water resources has drawn attention from scientists and the public.Land-use changes can have a significant impact on groundwater recharge in arid regions,and quantitative assessment of the impact is key to sustainable groundwater resources management.In this study,the changes of groundwater recharge after the conversion of natural lands to croplands were investigated and compared in inland and arid region,i.e.,the northern slope of the Tianshan Mountain.Stable isotopes suggest that soil water in topsoil(<2 m)has experienced stronger evaporation under natural lands than croplands,and then moves downward as a piston flow.Recharge was estimated by the tracer-based mass balance method,i.e.,chloride and sulfate.Recharge rates under natural conditions estimated by the chloride mass balance(CMB)method were estimated to be 0.07 mm/a in deserts and 0.4 mm/a in oases.In contrast,the estimated groundwater recharge ranged from 61.2 mm/a to 44.8 mm/a in croplands,indicating that groundwater recharge would increase significantly after land changes from natural lands to irrigated croplands in arid regions.Recharge estimated by the sulfate mass balance method is consistent with that from the CMB method,indicating that sulfate is also a good tracer capable of estimating groundwater recharge.展开更多
To identify the response of groundwater level variation to global climate change in Northwest China’s inland basins,the Golmud River Catchment was chosen as a case in this paper.Approaches of time series analysis and...To identify the response of groundwater level variation to global climate change in Northwest China’s inland basins,the Golmud River Catchment was chosen as a case in this paper.Approaches of time series analysis and correlation analysis were adopted to investigate the variation of groundwater level influenced by global climate change from 1977 to 2017.Results show that the temperature in the Golmud River Catchment rose 0.57℃ every 10 years.It is highly positive correlated with global climate temperature,with a correlation coefficient,0.87.The frequency and intensity of extreme precipitation were both increased.Generally,groundwater levels increased from 1977 to 2017 in all phreatic and confined aquifers and the fluctuation became more violent.Most importantly,extreme precipitation led to the fact that groundwater level rises sharply,which induced city waterlogging.However,no direct evidence shows that normal precipitation triggered groundwater level rise,and the correlation coefficients between precipitation data from Golmud meteorological station located in the Gobi Desert and groundwater level data of five observation wells are 0.13,0.02,−0.11,0.04,and−0.03,respectively.This phenomenon could be explained as that the main recharge source of groundwater is river leakage in the alluvial-pluvial Gobi plain because of the high total head of river water and goodness hydraulic conductivity of the vadose zone.Data analysis shows that glacier melting aggravated because of local temperature increased.As a result,runoff caused groundwater levels to ascend from 1977 to 2017.Correlation coefficients of two groundwater wells observation data and runoff of Golmud River are 0.80 and 0.68.The research results will contribute to handling the negative effects of climate change on groundwater for Northwestern China.展开更多
基金The research was funded by Innovation Capability Support Program of Shaanxi(2019TD-040)China National Natural Science Foundation(41472228,41877199)+1 种基金Groundwater and Ecology Security in the North Slope Economic Belt of the Tianshan Mountain(201511047)Key Laboratory of Groundwater and Ecology in Arid Regions of China Geological Survey.
文摘Regional aridity is increasing under global climate change,and therefore the sustainable use of water resources has drawn attention from scientists and the public.Land-use changes can have a significant impact on groundwater recharge in arid regions,and quantitative assessment of the impact is key to sustainable groundwater resources management.In this study,the changes of groundwater recharge after the conversion of natural lands to croplands were investigated and compared in inland and arid region,i.e.,the northern slope of the Tianshan Mountain.Stable isotopes suggest that soil water in topsoil(<2 m)has experienced stronger evaporation under natural lands than croplands,and then moves downward as a piston flow.Recharge was estimated by the tracer-based mass balance method,i.e.,chloride and sulfate.Recharge rates under natural conditions estimated by the chloride mass balance(CMB)method were estimated to be 0.07 mm/a in deserts and 0.4 mm/a in oases.In contrast,the estimated groundwater recharge ranged from 61.2 mm/a to 44.8 mm/a in croplands,indicating that groundwater recharge would increase significantly after land changes from natural lands to irrigated croplands in arid regions.Recharge estimated by the sulfate mass balance method is consistent with that from the CMB method,indicating that sulfate is also a good tracer capable of estimating groundwater recharge.
基金This research was supported by the National Natural Science Foundation of China(41672250,42177076)the Key R&D Projects of Shaanxi Province(2021ZDLSF05-09)the Natural Science Foundation of Shaanxi Province(2019JLZ-03).
文摘To identify the response of groundwater level variation to global climate change in Northwest China’s inland basins,the Golmud River Catchment was chosen as a case in this paper.Approaches of time series analysis and correlation analysis were adopted to investigate the variation of groundwater level influenced by global climate change from 1977 to 2017.Results show that the temperature in the Golmud River Catchment rose 0.57℃ every 10 years.It is highly positive correlated with global climate temperature,with a correlation coefficient,0.87.The frequency and intensity of extreme precipitation were both increased.Generally,groundwater levels increased from 1977 to 2017 in all phreatic and confined aquifers and the fluctuation became more violent.Most importantly,extreme precipitation led to the fact that groundwater level rises sharply,which induced city waterlogging.However,no direct evidence shows that normal precipitation triggered groundwater level rise,and the correlation coefficients between precipitation data from Golmud meteorological station located in the Gobi Desert and groundwater level data of five observation wells are 0.13,0.02,−0.11,0.04,and−0.03,respectively.This phenomenon could be explained as that the main recharge source of groundwater is river leakage in the alluvial-pluvial Gobi plain because of the high total head of river water and goodness hydraulic conductivity of the vadose zone.Data analysis shows that glacier melting aggravated because of local temperature increased.As a result,runoff caused groundwater levels to ascend from 1977 to 2017.Correlation coefficients of two groundwater wells observation data and runoff of Golmud River are 0.80 and 0.68.The research results will contribute to handling the negative effects of climate change on groundwater for Northwestern China.
