Recharge and discharge, such as rainfall infiltration and evapotranspiration in vertical direction, are major processes of water cycle in the shallow groundwater area of the North China Plain. During these processes, ...Recharge and discharge, such as rainfall infiltration and evapotranspiration in vertical direction, are major processes of water cycle in the shallow groundwater area of the North China Plain. During these processes, soil water movement in the unsaturated zone plays an important role in the transformation from rainfall infiltration to groundwater. The soil water movement models were developed by using HYDRUS-1D software at two typical experimental sites in Cangzhou(CZ) and Hengshui(HS) with different soil, vegetation and similar climate conditions. As shown in the results, the comparison in precipitation infiltration features between the two sites is distinct. The soil water experiences strong evaporation after precipitation infiltration, which accounts for 63% of the total infiltration at the HS site where the soil is homogenous. It is this strong evaporation effect that leads to slight increase of soil water storage. At the CZ site, where the soil is heterogeneous, the evaporation effect exists from July to October of the simulation period. The total evaporation accounts for 33% of the total infiltration, and the evaporation rate is slow. At the end of the simulation period, the soil water storage increases and the water table decreases, indicating a strong storage capacity at this site.展开更多
This is a certain quantity of available groundwater resources in the form of freshwater lens according to the survey and drilling experiment along the oil transporting highway in the Taklimakan Desert, which is the se...This is a certain quantity of available groundwater resources in the form of freshwater lens according to the survey and drilling experiment along the oil transporting highway in the Taklimakan Desert, which is the second largest moving desert in the world, located in the northwest part of China. As the primary freshwater sources, local precipitation in the heartland of Taklimakan Desert, not only forms the runoff on the clayey ground, but also feeds the groundwater. After the analysis of historic records of the rainfall and the formation of clayey sediments, the precipitation infiltration and runoff recharging experiment was conducted, a natural rainfall runoff process was observed and recorded. The studied area referred to this paper is located in the middle part of the desert, within 6 km wide and 60 km long along the new oil transporting highway. This paper reveals that in the center of the desert an event of storm (4?mm) can be considered as the critical value of the runoff produced on the clayey ground. The rainfall infiltration coefficients on the sand dunes are over 0.46 for the erosion side, thus, rainstorms and runoffs as main fresh water sources feed the ground water directly.展开更多
Coal mining subsidence is a universal environmental-geological problem in mining areas. By selecting the Shen-Dong coal mining subsidence area as the research field, this paper studies the changes in precipitation inf...Coal mining subsidence is a universal environmental-geological problem in mining areas. By selecting the Shen-Dong coal mining subsidence area as the research field, this paper studies the changes in precipitation infiltration recharge in the circumstances of coal mining subsidence by means of field geological investigation and laboratory simulation experiments, which is expected to provide a scientific basis for eco-environmental restoration in the mining area. The results indicate that at the unstable stage of subsidence, three types of subsidence in the Shen-Dong mining area have positive effects on the precipitation infiltration recharge, and the type of full-thickness bedrock subsidence has the greatest influence. In the stable stage of subsidence, the precipitation infiltration process after long- term drought and the moisture migration in the aeration zone undergo three different stages： evaporation-infiltration before precipitation, infiltration-upward infiltration-infiltration during precipitation and evaporation-infiltration after precipitation. During a heavy rainfall infiltration process, the wetting front movement in fine sand, coarse sand and dualistic structure of fine-coarse sand consists of two stages： the stage of wetting front movement during precipitation, in which the wetting front movement distance has linear relationship with the depth, and the stage of wetting front movement after precipitation, in which the wetting front movement distance has the power function relationship with the depth. The wetting front movement velocity is influenced by the rainfall amount and the lithology in the aeration zone. However, as the depth increases, the movement velocity will decay exponentially.展开更多
基金financially supported by the 100-Talent Project of Chinese Academy of Sciencesthe Key Program of the National Natural Science Foundation of China (No.41471028)
文摘Recharge and discharge, such as rainfall infiltration and evapotranspiration in vertical direction, are major processes of water cycle in the shallow groundwater area of the North China Plain. During these processes, soil water movement in the unsaturated zone plays an important role in the transformation from rainfall infiltration to groundwater. The soil water movement models were developed by using HYDRUS-1D software at two typical experimental sites in Cangzhou(CZ) and Hengshui(HS) with different soil, vegetation and similar climate conditions. As shown in the results, the comparison in precipitation infiltration features between the two sites is distinct. The soil water experiences strong evaporation after precipitation infiltration, which accounts for 63% of the total infiltration at the HS site where the soil is homogenous. It is this strong evaporation effect that leads to slight increase of soil water storage. At the CZ site, where the soil is heterogeneous, the evaporation effect exists from July to October of the simulation period. The total evaporation accounts for 33% of the total infiltration, and the evaporation rate is slow. At the end of the simulation period, the soil water storage increases and the water table decreases, indicating a strong storage capacity at this site.
文摘This is a certain quantity of available groundwater resources in the form of freshwater lens according to the survey and drilling experiment along the oil transporting highway in the Taklimakan Desert, which is the second largest moving desert in the world, located in the northwest part of China. As the primary freshwater sources, local precipitation in the heartland of Taklimakan Desert, not only forms the runoff on the clayey ground, but also feeds the groundwater. After the analysis of historic records of the rainfall and the formation of clayey sediments, the precipitation infiltration and runoff recharging experiment was conducted, a natural rainfall runoff process was observed and recorded. The studied area referred to this paper is located in the middle part of the desert, within 6 km wide and 60 km long along the new oil transporting highway. This paper reveals that in the center of the desert an event of storm (4?mm) can be considered as the critical value of the runoff produced on the clayey ground. The rainfall infiltration coefficients on the sand dunes are over 0.46 for the erosion side, thus, rainstorms and runoffs as main fresh water sources feed the ground water directly.
基金supported by the National Natural Science Foundation of China(No.41130637, No.40472124)International Cooperation Projects of Ministry of Science and Technology(2005DFA90200)
文摘Coal mining subsidence is a universal environmental-geological problem in mining areas. By selecting the Shen-Dong coal mining subsidence area as the research field, this paper studies the changes in precipitation infiltration recharge in the circumstances of coal mining subsidence by means of field geological investigation and laboratory simulation experiments, which is expected to provide a scientific basis for eco-environmental restoration in the mining area. The results indicate that at the unstable stage of subsidence, three types of subsidence in the Shen-Dong mining area have positive effects on the precipitation infiltration recharge, and the type of full-thickness bedrock subsidence has the greatest influence. In the stable stage of subsidence, the precipitation infiltration process after long- term drought and the moisture migration in the aeration zone undergo three different stages： evaporation-infiltration before precipitation, infiltration-upward infiltration-infiltration during precipitation and evaporation-infiltration after precipitation. During a heavy rainfall infiltration process, the wetting front movement in fine sand, coarse sand and dualistic structure of fine-coarse sand consists of two stages： the stage of wetting front movement during precipitation, in which the wetting front movement distance has linear relationship with the depth, and the stage of wetting front movement after precipitation, in which the wetting front movement distance has the power function relationship with the depth. The wetting front movement velocity is influenced by the rainfall amount and the lithology in the aeration zone. However, as the depth increases, the movement velocity will decay exponentially.
