水、土、能是人类生存和发展的重要自然资源。基于稳定性(S)、协调性(H)、可持续性(F)构建安徽省“水-土-能”系统安全评价指标体系,利用“单指标量化-多指标综合-多准则集成”(Single index quantification-multi-index comprehensive-...水、土、能是人类生存和发展的重要自然资源。基于稳定性(S)、协调性(H)、可持续性(F)构建安徽省“水-土-能”系统安全评价指标体系,利用“单指标量化-多指标综合-多准则集成”(Single index quantification-multi-index comprehensive-multi-criteria integration,SMI-P)法测算各子系统指数及其系统安全水平,引入Copula函数分别探究S-H、S-F、H-F和S-H-F等不同组合的联合概率分布,测算其联合风险概率。结果显示:2012—2021年,安徽省“水-土-能”(“Water-Land-Energy”,WLE)系统安全水平波动上升,均值为0.5685,其中稳定性对系统安全水平影响最大;S-H、S-F、H-F分别呈弱正相关、强正相关、较强负相关关系,S-F联合风险概率最大,为0.2807;S-H-F系统联合风险概率为0.0712。当S、H、F其中一个固定时,另外两个的值越大,相应的联合风险概率越大。探究“水-土-能”系统安全水平及风险发生频率,有利于保障区域可持续发展,提高风险分析精度,为决策部门提供有效信息。展开更多
The impact of land-use on distributed groundwater recharge and discharge in the western Jilin (WJ) was analyzed in this study. WJ is a transitional, semi-arid zone with a fragile, hydrological closed ecosystem in the ...The impact of land-use on distributed groundwater recharge and discharge in the western Jilin (WJ) was analyzed in this study. WJ is a transitional, semi-arid zone with a fragile, hydrological closed ecosystem in the Songhua River Basin (SRB). The research tool includes a seamlessly linked MODFLOW, WetSpass, the Seepage packages, and ArcGIS. The model calibration showed good agreement between simulated water table elevation and measured water table depths, while predicted groundwater discharge zones showed strong correlations with field occurrences of drainage systems and wetlands. Simulated averages for distributed recharge, water table elevation and groundwater drawdown were 377.42mm/yr, 194.43m, and 0.18m respectively. Forest vegetation showed the highest recharge, followed by ag- ricultural farmlands, while open-water and other drainage systems constituted groundwater exit zones. When present land-use conditions were compared with the hypothetical natural pre-development scenario, an overall loss of ground- water recharge (24.09mm/yr) was observed, which for the project area is 18.05×108m3. Groundwater abstraction seemed to be the cause of water table drawdown, especially in the immediate vicinities of the supply wells. An important issue of the findings was the ability of the hypothetical forest vegetation to protect, and hence sustain aquifer reserves and dependent ecosystems. The profound data capture capability of ArcGIS makes it particularly useful in spa- tio-temporal hydroecological modeling.展开更多
In this paper, the hydraulic resistances and capacitances were evaluated. based on the development of non-(?) model of water flow in the soil-plant system and the simulating experiment work.The results show that the m...In this paper, the hydraulic resistances and capacitances were evaluated. based on the development of non-(?) model of water flow in the soil-plant system and the simulating experiment work.The results show that the mean hydraulic resistance in the soil-plant system is 6.79×109 MPa·S·m-3; the mean hydraulic capacitance in the system is 5.2×107m3·MPa-1. In the components of hydraulic capacitance in the system, the capacitance in soil (81.8×10-6m3·MPa ) is the biggest and its variability with suii water potential is extremely strong, the capacitance in plant (5.3×10-7m3·MPa-1) is much smaller than that in soil, and the capacitance in shoots (15.5×10-7m3·2MPa-1) is bigger than that in roots (8.4×10-7m3·2MPa-1). An interesting result is that the capacitance in plant is almost equivalent to that in the soil-plant system.展开更多
A tillage method of combining ridge with no-tillage (RNT) was employed in lowland rice-based cropping system to study the long-term effects of RNT on soil profile pattern, soil water stable aggregate distribution, nut...A tillage method of combining ridge with no-tillage (RNT) was employed in lowland rice-based cropping system to study the long-term effects of RNT on soil profile pattern, soil water stable aggregate distribution, nutrients stratification and yields of rice and post-rice crops. After flooded paddy field (FPF) was practiced with RNT for a long time, soil profile changed from G to A-P-G, and horizon G was shifted to a deeper position in the profile. Also the proportion of macroaggregate (> 2 mm) increased, whereas the proportion of silt and clay (< 0.053 mm) decreased under RNT, indicating a better soil structure that will prevent erosion. RNT helped to control leaching and significantly improved total N, P, K and organic matter in soil. The highest crop yields were found under RNT system every year, and total crop yields were higher under conventional paddy-upland rotation tillage (CR) than under FPF, except in 2003 and 2006 when serious drought occurred. RNT was proven to be a better tillage method for lowland rice-based cropping system.展开更多
The pull-out capacities for soil nailing systems comprising of one single 29 mm diameter(type A) and four 16 mm diameter(type B) rebars with grouted cement were examined.A field test and numerical analysis for the typ...The pull-out capacities for soil nailing systems comprising of one single 29 mm diameter(type A) and four 16 mm diameter(type B) rebars with grouted cement were examined.A field test and numerical analysis for the type A and type B systems were carried out to investigate the pull-out capacities and the slope stability reinforcement efficiency in soil and rock slopes.The results of the pull-out tests show the mobilized shear force and load transfer characteristics with respect to soil depth.The load-displacement relationship was examined for both type A and type B systems.Slope stability analyses were carried out to study the relationships between soil and nail reinforcement and bending stiffness as well as combined axial tension and shear forces.Factors of safety were calculated in relation to the number of nails and their outside diameters.Both soil and rock slopes were included in this evaluation.展开更多
After the Tianjin Port 8.12 explosion, an enormous amount of potassium dichromate （K2Cr2O7） and butanone （CH3COCH2CH3） leaked into the coastal soil-groundwater system, which potentially threatened the environment ...After the Tianjin Port 8.12 explosion, an enormous amount of potassium dichromate （K2Cr2O7） and butanone （CH3COCH2CH3） leaked into the coastal soil-groundwater system, which potentially threatened the environment and human health. Determining the transport process of hazards is necessary to establish guidelines for remediating the contaminated area. This work aims to investigate the migration of potassium dichromate and butanone in the coastal soil-groundwater system through a coupling unsaturated-saturated numerical model, incorporating the HYDRUS model into the MODFLOW/ MT3D model. In the unsaturated zone, two-dimensional HYDRUS model was applied, and its recharge flux at the bottom boundary was utilized as the input of MODFLOW/MT3D model in the saturated zone. Results showed that Cr2O^（2-）7 migrated much faster than butanone in the unsaturated zone and reached the water table in about 1 year. In comparison, butanone was unlikely to enter the aquifer even 5 years later with a migration depth of about 2.2 m. Driven by groundwater, the Cr2O^（2-）7 that entered the aquifer migrated about 161 m toward southeast 5 years later. In the saturated zone, the contamination plume covered mainly the southeast area due to the groundwater flow direction.展开更多
Denitrification is an important process of nitrogen removal in lake ecosystems.However,the importance of denitrification across the entire soil-depth gradients including subsurface layers remains poorly understood.Thi...Denitrification is an important process of nitrogen removal in lake ecosystems.However,the importance of denitrification across the entire soil-depth gradients including subsurface layers remains poorly understood.This study aims to determine the spatial pattern of soil denitrification enzyme activity(DEA) and its environmental determinants across the entire soil depth gradients in the raised fields in Baiyang Lake,North China.In two different zones of the raised fields(i.e.,water boundary vs.main body of the raised fields),the soil samples from 1.0 m to 1.1 m depth were collected,and the DEA and following environmental determinants were quantified:soil moisture,p H,total nitrogen(TN),ammonia nitrogen(NH4+-N),nitrate nitrogen(NO3–-N),total organic carbon(TOC),and rhizome biomass of Phragmites australis.The results showed that the soil DEA and environmental factors had a striking zonal distribution across the entire soil depth gradients.The soil DEA reached two peak values in the upper and middle soil layers,indicating that denitrification are important in both topsoil and subsurface of the raised fields.The correlation analysis showed that the DEA is negatively correlated with the soil depth(p < 0.05).However,this phenomenon did not occur in the distance to the water edge,except in the upper layers(from 0.2 m to 0.7 m) of the boundary zone of the raised fields.In the main body of the raised fields,the DEA level remained high;however,it showed no significant relationship with the distance to the water edge.The linear regression analysis showed significant positive correlation of the DEA with the soil TN,NO3–-N,NH4+-N,and TOC;whereas it showed negative correlation with soil p H.No significant correlations with soil moisture and temperature were observed.A positive correlation was also found between the DEA and rhizome biomass of P.australis.展开更多
文摘水、土、能是人类生存和发展的重要自然资源。基于稳定性(S)、协调性(H)、可持续性(F)构建安徽省“水-土-能”系统安全评价指标体系,利用“单指标量化-多指标综合-多准则集成”(Single index quantification-multi-index comprehensive-multi-criteria integration,SMI-P)法测算各子系统指数及其系统安全水平,引入Copula函数分别探究S-H、S-F、H-F和S-H-F等不同组合的联合概率分布,测算其联合风险概率。结果显示:2012—2021年,安徽省“水-土-能”(“Water-Land-Energy”,WLE)系统安全水平波动上升,均值为0.5685,其中稳定性对系统安全水平影响最大;S-H、S-F、H-F分别呈弱正相关、强正相关、较强负相关关系,S-F联合风险概率最大,为0.2807;S-H-F系统联合风险概率为0.0712。当S、H、F其中一个固定时,另外两个的值越大,相应的联合风险概率越大。探究“水-土-能”系统安全水平及风险发生频率,有利于保障区域可持续发展,提高风险分析精度,为决策部门提供有效信息。
文摘The impact of land-use on distributed groundwater recharge and discharge in the western Jilin (WJ) was analyzed in this study. WJ is a transitional, semi-arid zone with a fragile, hydrological closed ecosystem in the Songhua River Basin (SRB). The research tool includes a seamlessly linked MODFLOW, WetSpass, the Seepage packages, and ArcGIS. The model calibration showed good agreement between simulated water table elevation and measured water table depths, while predicted groundwater discharge zones showed strong correlations with field occurrences of drainage systems and wetlands. Simulated averages for distributed recharge, water table elevation and groundwater drawdown were 377.42mm/yr, 194.43m, and 0.18m respectively. Forest vegetation showed the highest recharge, followed by ag- ricultural farmlands, while open-water and other drainage systems constituted groundwater exit zones. When present land-use conditions were compared with the hypothetical natural pre-development scenario, an overall loss of ground- water recharge (24.09mm/yr) was observed, which for the project area is 18.05×108m3. Groundwater abstraction seemed to be the cause of water table drawdown, especially in the immediate vicinities of the supply wells. An important issue of the findings was the ability of the hypothetical forest vegetation to protect, and hence sustain aquifer reserves and dependent ecosystems. The profound data capture capability of ArcGIS makes it particularly useful in spa- tio-temporal hydroecological modeling.
文摘In this paper, the hydraulic resistances and capacitances were evaluated. based on the development of non-(?) model of water flow in the soil-plant system and the simulating experiment work.The results show that the mean hydraulic resistance in the soil-plant system is 6.79×109 MPa·S·m-3; the mean hydraulic capacitance in the system is 5.2×107m3·MPa-1. In the components of hydraulic capacitance in the system, the capacitance in soil (81.8×10-6m3·MPa ) is the biggest and its variability with suii water potential is extremely strong, the capacitance in plant (5.3×10-7m3·MPa-1) is much smaller than that in soil, and the capacitance in shoots (15.5×10-7m3·2MPa-1) is bigger than that in roots (8.4×10-7m3·2MPa-1). An interesting result is that the capacitance in plant is almost equivalent to that in the soil-plant system.
基金Project supported by the National Natural Science Foundation of China (No.40501033)the National Key Technologies R&D Program for the 11th Five-Year Plan of China (No.2007BAD87B10)
文摘A tillage method of combining ridge with no-tillage (RNT) was employed in lowland rice-based cropping system to study the long-term effects of RNT on soil profile pattern, soil water stable aggregate distribution, nutrients stratification and yields of rice and post-rice crops. After flooded paddy field (FPF) was practiced with RNT for a long time, soil profile changed from G to A-P-G, and horizon G was shifted to a deeper position in the profile. Also the proportion of macroaggregate (> 2 mm) increased, whereas the proportion of silt and clay (< 0.053 mm) decreased under RNT, indicating a better soil structure that will prevent erosion. RNT helped to control leaching and significantly improved total N, P, K and organic matter in soil. The highest crop yields were found under RNT system every year, and total crop yields were higher under conventional paddy-upland rotation tillage (CR) than under FPF, except in 2003 and 2006 when serious drought occurred. RNT was proven to be a better tillage method for lowland rice-based cropping system.
文摘The pull-out capacities for soil nailing systems comprising of one single 29 mm diameter(type A) and four 16 mm diameter(type B) rebars with grouted cement were examined.A field test and numerical analysis for the type A and type B systems were carried out to investigate the pull-out capacities and the slope stability reinforcement efficiency in soil and rock slopes.The results of the pull-out tests show the mobilized shear force and load transfer characteristics with respect to soil depth.The load-displacement relationship was examined for both type A and type B systems.Slope stability analyses were carried out to study the relationships between soil and nail reinforcement and bending stiffness as well as combined axial tension and shear forces.Factors of safety were calculated in relation to the number of nails and their outside diameters.Both soil and rock slopes were included in this evaluation.
基金supported by the National Natural Science Foundation of China(No.21656001)
文摘After the Tianjin Port 8.12 explosion, an enormous amount of potassium dichromate （K2Cr2O7） and butanone （CH3COCH2CH3） leaked into the coastal soil-groundwater system, which potentially threatened the environment and human health. Determining the transport process of hazards is necessary to establish guidelines for remediating the contaminated area. This work aims to investigate the migration of potassium dichromate and butanone in the coastal soil-groundwater system through a coupling unsaturated-saturated numerical model, incorporating the HYDRUS model into the MODFLOW/ MT3D model. In the unsaturated zone, two-dimensional HYDRUS model was applied, and its recharge flux at the bottom boundary was utilized as the input of MODFLOW/MT3D model in the saturated zone. Results showed that Cr2O^（2-）7 migrated much faster than butanone in the unsaturated zone and reached the water table in about 1 year. In comparison, butanone was unlikely to enter the aquifer even 5 years later with a migration depth of about 2.2 m. Driven by groundwater, the Cr2O^（2-）7 that entered the aquifer migrated about 161 m toward southeast 5 years later. In the saturated zone, the contamination plume covered mainly the southeast area due to the groundwater flow direction.
基金Under the auspices of National Science Fund for Distinguished Young Scholars(No.51125035)National Science Foundation for Innovative Research Group(No.51121003)Major Science and Technology Program for Water Pollution Control and Treatment(No.2009ZX07209-008)
文摘Denitrification is an important process of nitrogen removal in lake ecosystems.However,the importance of denitrification across the entire soil-depth gradients including subsurface layers remains poorly understood.This study aims to determine the spatial pattern of soil denitrification enzyme activity(DEA) and its environmental determinants across the entire soil depth gradients in the raised fields in Baiyang Lake,North China.In two different zones of the raised fields(i.e.,water boundary vs.main body of the raised fields),the soil samples from 1.0 m to 1.1 m depth were collected,and the DEA and following environmental determinants were quantified:soil moisture,p H,total nitrogen(TN),ammonia nitrogen(NH4+-N),nitrate nitrogen(NO3–-N),total organic carbon(TOC),and rhizome biomass of Phragmites australis.The results showed that the soil DEA and environmental factors had a striking zonal distribution across the entire soil depth gradients.The soil DEA reached two peak values in the upper and middle soil layers,indicating that denitrification are important in both topsoil and subsurface of the raised fields.The correlation analysis showed that the DEA is negatively correlated with the soil depth(p < 0.05).However,this phenomenon did not occur in the distance to the water edge,except in the upper layers(from 0.2 m to 0.7 m) of the boundary zone of the raised fields.In the main body of the raised fields,the DEA level remained high;however,it showed no significant relationship with the distance to the water edge.The linear regression analysis showed significant positive correlation of the DEA with the soil TN,NO3–-N,NH4+-N,and TOC;whereas it showed negative correlation with soil p H.No significant correlations with soil moisture and temperature were observed.A positive correlation was also found between the DEA and rhizome biomass of P.australis.
