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Chinese Academy of Geological Sciences (2021)

Study on the Evolution Mechanism of Water Cycle in Semi-arid Areas under Large-scale Vegetation Restoration ——A Case Study of Beichuan River

朱亮

Titre : Study on the Evolution Mechanism of Water Cycle in Semi-arid Areas under Large-scale Vegetation Restoration ——A Case Study of Beichuan River

Auteur : 朱亮

Grade : Doctoral Dissertation 2021

Université : Chinese Academy of Geological Sciences

Résumé partiel
Since 1970s,China’s land greening has achieved remarkable results,and it has played an important role in water and soil conservation and wind prevention and sand fixation.At the same time,large-scale vegetation restoration has caused drastic changes in the underlying surface pattern,which has a profound impact on regional water cycle conditions and hydrological processes.Especially in water-scarce areas in northern China,local vegetation restoration is approaching the limit of sustainable use of water resources.A new ecological-water resource contradiction has emerged.Therefore,in-depth research on the evolution mechanism of the water cycle under the effect of large-scale vegetation restoration is significant to scientifically understand the coordinated development of ecology and water resources in water-scarce areas.,Focusing on the impact of vegetation restoration on water resources in semi-arid areas,This paper takes Beichuan River Basin,a secondary tributary of the upper reaches of the Yellow River,as the research object.First,through soil moisture monitoring in different vegetation coverage areas and rainfall infiltration replenishment tracing experiments,the regulation mechanism of artificial shrub vegetation restoration on the conversion process of precipitation-soil water-groundwater was revealed.Then combined with long-term meteorological,hydrological data and remote sensing data to analyze the evolution trend of water cycle elements at the basin scale,and clarify the effect of vegetation restoration on the evolution of key water cycle elements.Finally,through the Water Resources Multiplier Effect Model,the significance of vegetation restoration in improving the effective utilization of water resources in the basin is clarified from the perspective of generalized water resources.The research results show that :(1)Artificial shrub vegetation restoration can enhance the water permeability and water storage capacity of shallow soils,and promote the water cycle of shallow soils.The average porosity,saturated hydraulic conductivity and water content of the soil profile(D1)of the high-coverage shrubland are 1.04 times,3.83 times and 1.5 times that of the sparse grassland soil profile(D2)respectively.The cumulative increase,average growth rate,cumulative consumption,and average consumption rate of soil moisture in the D1 profile are 1.67 times,5.5 times,2.03 times and 3.2 times that of the D2 profile respectively.The cumulative increase and consumption of soil water at the depth of 0-20 cm account for more than 89%,which is the most critical layer that affects the soil water cycle.(2)Shrubs with high coverage can weaken the recharge of deep soil moisture and groundwater by rainfall to a certain extent.During the test period,the rainfall infiltration replenishment of groundwater in D1 and D2 areas were 11.08 mm and 15.46 mm,respectively,of which the dominant flow accounted for 31.4%and 42.7% respectively

Mots clés : Soil water ;Groundwater recharge ;Ecological water consumption ;Water cycle ;Water conservation ;

Présentation (CNKI)https://oversea.cnki.net/KCMS/detai...

Page publiée le 21 octobre 2021