As a basic natural resource and strategic economic resource,the development and utilization of water resources is an important issue related to the national economy and people's livelihood.How to scientifically ev...As a basic natural resource and strategic economic resource,the development and utilization of water resources is an important issue related to the national economy and people's livelihood.How to scientifically evaluate the water resources carrying capacity is the premise to improve the regional water resources carrying capacity and ensure the regional water security.The Gansu section of the Yellow River basin is an important water conservation and recharge area.Whether the water resources in this area can ensure the normal operation of the ecosystem and whether it can carry the sustainable development of social economy is the key to realize the high-quality development of the Yellow River basin.In this study,from the three dimensions of water consumption per capita,water consumption of 10000 yuan GDP and ecological water use rate,by constructing the evaluation index system and index grading standard of water resources carrying capacity,the fuzzy comprehensive evaluation model was used to evaluate the water resources carrying capacity of Gansu section of the Yellow River Basin,in order to provide theoretical decision-making basis for the comprehensive development,utilization and planning management of water resources in Gansu section of the Yellow River basin and even the whole basin,and help the high-quality development of the Yellow River basin.展开更多
The application of dams built upstream will change the input conditions, including water and sediment, of downstream fluvial system, and destroy previous dynamic quasi-equilibrium reached by channel streamflow, so ind...The application of dams built upstream will change the input conditions, including water and sediment, of downstream fluvial system, and destroy previous dynamic quasi-equilibrium reached by channel streamflow, so indispensable adjustments are necessary for downstream channel to adapt to the new water and sediment supply, leading the fluvial system to restore its previous equilibrium or reach a new equilibrium. Using about 50-year-long hydrological, sedimentary and cross-sectional data, temporal response processes of Toudaoguai cross-section located in the upper Yellow River to the operation of reservoirs built upstream are analyzed. The results show that the Toudaoguai cross-section change was influenced strongly by upstream reservoir operation and downstream channel bed armoring thereafter occurred gradually and extended to the reach below Sanhuhekou gauging station. Besides, median diameter of suspended sediment load experienced a three-stage change that is characterized by an increase at first, then a decrease and an increase again finally, which reflects the process of channel bed armoring that began at Qingtongxia reservoir and then gradually developed downstream to the reach below Sanhuhekou cross-section. Since the joint operation strategy of Longyangxia, Liujiaxia and Qingtongxia reservoirs was introduced in 1986, the three-stage change trend has become less evident than that in the time period between 1969 and 1986 when only Qingtongxia and Liujiaxia reservoirs were put into operation alone. In addition, since 1987, the extent of lateral migration and thalweg elevation change at Toudaoguai cross-section has reduced dramatically, cross-sectional profile and location tended to be stable, which is beneficial to the normal living for local people.展开更多
The change characteristics and trends of the regional climate in the source region of the Yellow River, and the response of runoff to climate change, are analyzed based on observational data of air temperature, precip...The change characteristics and trends of the regional climate in the source region of the Yellow River, and the response of runoff to climate change, are analyzed based on observational data of air temperature, precipitation, and runoff at 10 main hydrological and weather stations in the region. Our results show that a strong signal of climate shift from warm-dry to warm-humid in the western parts of northwestern China （Xinjiang） and the western Hexi Corridor of Gansu Province occurred in the late 1980s, and a same signal of climate change occurred in the mid-2000s in the source region of the Yellow River located in the eastern part of northwestern China. This climate changeover has led to a rapid increase in rainfall and stream runoff in the latter region. In most of the years since 2004 the average annual precipitation in the source region of the Yellow River has been greater than the long-term average annual value, and after 2007 the runoff measured at all of the hydrologic sections on the main channel of the Yellow River in the source region has also consistently exceeded the long-term average annual because of rainfall increase. It is difficult to determine the prospects of future climate change until additional observations and research are conducted on the rate and temporal and spatial extents of climate change in the region. Nevertheless, we predict that the climate shift from warm-dry to warm-humid in the source region of the Yellow River is very likely to be in the decadal time scale, which means a warming and rainy climate in the source region of the Yellow River will continue in the coming decades.展开更多
To understand the non-equilibrium morphological adjustment of a river in response to environmental changes,it is essential to(i)accurately identify how past conditions of water and sediment have impacted current morph...To understand the non-equilibrium morphological adjustment of a river in response to environmental changes,it is essential to(i)accurately identify how past conditions of water and sediment have impacted current morphological adjustment of the river,and(ii)establish a corresponding simulation for non-equilibrium conditions.Based on discharge and suspended sediment concentration(SSC)as well as 82 cross-sectional data items for the Huayuankou-Lijin reach of the Lower Yellow River in the period 1965-2015,the process of adjustment of the geometry of the main channel(area,width,depth,and geomorphic coefficient),and its responses to changes in discharge and SSC for different reaches are statistically analyzed.Following this,a delayed response model(DRM)of the geometry of the main channel subjected to variations in discharge and SSC is established using a multi-step analytical model,with the discharge and SSC as the main controlling factors.The results show that the area,width,and depth of the main channel decreased initially,then increased,decreased again,and finally increased again.These features of the geometry of the channel were positively correlated with the 4-year moving average discharge and negatively with the 4-year moving average SSC.The geomorphic coefficient for the Huayuankou-Sunkou reach exhibited a trend of decrease,whereas that of the Sunkou-Lijin reach decreased initially,then increased,decreased again,and finally increased again.Except for the Huayuankou-Gaocun reach in 1965-1999,the coefficient was negatively correlated with the 4-year moving average discharge and positively with SSC.The simulated values of the morphological parameters of the main channel for all sub-reaches obtained using the DRM agreed well with the measured values.This indicates that the DRM can be used to simulate the process of response of the cross-sectional geometry of the main channel to variations in the water and sediment.The results of the model show that the adjustment of the geometry of the main channel was affected by the discharge and the SSC at present(30%)as well as for the previous 7 years(70%).The proposed model offers insights into the mechanism whereby past water and sediment influence the current morphological adjustment of the river,and provides an effective method for predicting the magnitude and trend of the geometry of the main channel under different flow conditions.展开更多
黄河流域山西段是重要的生态屏障区,明晰生态系统服务权衡/协同强度的时空格局,对生态保护及经济协调发展具有重要意义。本文基于生态系统服务和权衡的综合评估模型(Integrated Valuation of Ecosystem Services and Tradeoffs,InVEST)...黄河流域山西段是重要的生态屏障区,明晰生态系统服务权衡/协同强度的时空格局,对生态保护及经济协调发展具有重要意义。本文基于生态系统服务和权衡的综合评估模型(Integrated Valuation of Ecosystem Services and Tradeoffs,InVEST)量化生态系统服务供给量和需求量,通过均方根偏差(Root Mean Square Deviation,RMSD)量化生态系统服务权衡强度,利用结构方程模型(Structural Equation Model,SEM)分析权衡强度的驱动因素。结果表明:(1)2000—2020年产水(Water Yield,WY)和土壤保持服务(Soil Conservation,SC)、产水和固碳服务(Carbon Sequestration,CS)供给权衡强度呈上升趋势,产水和土壤保持服务、产水和固碳服务需求协同强度呈下降趋势。(2)除产水服务在2020年供给—需求权衡强度大于0,2000—2020年产水、土壤保持和固碳服务的供给—需求权衡强度均小于0。(3)生态系统服务权衡/协同强度主要受自然因素影响,蒸散发对产水和土壤保持服务、产水和固碳服务供给权衡具有促进作用,对产水服务供给—需求权衡具有抑制作用;草地面积占比对产水和固碳服务供给权衡及产水和土壤保持服务需求协同具有抑制作用,对固碳服务供给—需求权衡具有促进作用;降水对产水和固碳服务需求协同及土壤保持服务供给—需求权衡具有抑制作用,对产水服务供给—需求权衡具有促进作用。(4)社会经济因素对生态系统服务权衡/协同强度具有次要作用,人口密度对产水和土壤保持服务需求协同具有促进作用,而对产水服务供给—需求权衡及固碳服务供给—需求权衡具有抑制作用。因此,在制定流域综合管理决策时应考虑生态系统服务权衡/协同强度的空间特征和驱动因素的差异性。展开更多
基金Supported by Gansu Province 2023 Education Science and Technology Innovation Project(2023B-431).
文摘As a basic natural resource and strategic economic resource,the development and utilization of water resources is an important issue related to the national economy and people's livelihood.How to scientifically evaluate the water resources carrying capacity is the premise to improve the regional water resources carrying capacity and ensure the regional water security.The Gansu section of the Yellow River basin is an important water conservation and recharge area.Whether the water resources in this area can ensure the normal operation of the ecosystem and whether it can carry the sustainable development of social economy is the key to realize the high-quality development of the Yellow River basin.In this study,from the three dimensions of water consumption per capita,water consumption of 10000 yuan GDP and ecological water use rate,by constructing the evaluation index system and index grading standard of water resources carrying capacity,the fuzzy comprehensive evaluation model was used to evaluate the water resources carrying capacity of Gansu section of the Yellow River Basin,in order to provide theoretical decision-making basis for the comprehensive development,utilization and planning management of water resources in Gansu section of the Yellow River basin and even the whole basin,and help the high-quality development of the Yellow River basin.
基金National Natural Science Foundation of China, No.40771031 Thanks are expressed to the Yellow River Conservancy Commission and International Network on Erosion and Sedimentation for the permission of access to hydrometric data. We are also grateful to Dr. Wang Xiujie from Tianjin University for his generous help.
文摘The application of dams built upstream will change the input conditions, including water and sediment, of downstream fluvial system, and destroy previous dynamic quasi-equilibrium reached by channel streamflow, so indispensable adjustments are necessary for downstream channel to adapt to the new water and sediment supply, leading the fluvial system to restore its previous equilibrium or reach a new equilibrium. Using about 50-year-long hydrological, sedimentary and cross-sectional data, temporal response processes of Toudaoguai cross-section located in the upper Yellow River to the operation of reservoirs built upstream are analyzed. The results show that the Toudaoguai cross-section change was influenced strongly by upstream reservoir operation and downstream channel bed armoring thereafter occurred gradually and extended to the reach below Sanhuhekou gauging station. Besides, median diameter of suspended sediment load experienced a three-stage change that is characterized by an increase at first, then a decrease and an increase again finally, which reflects the process of channel bed armoring that began at Qingtongxia reservoir and then gradually developed downstream to the reach below Sanhuhekou cross-section. Since the joint operation strategy of Longyangxia, Liujiaxia and Qingtongxia reservoirs was introduced in 1986, the three-stage change trend has become less evident than that in the time period between 1969 and 1986 when only Qingtongxia and Liujiaxia reservoirs were put into operation alone. In addition, since 1987, the extent of lateral migration and thalweg elevation change at Toudaoguai cross-section has reduced dramatically, cross-sectional profile and location tended to be stable, which is beneficial to the normal living for local people.
基金supported by the Key Deployment Project of the Chinese Academy of Sciences (Grant No. Y322G73001)the Major Research Projects of the National Natural Science Fund Project (Grant No. 91225302)the National Natural Science Foundation of China (NSFC) (Grant Nos. 41240002 and 91225301)
文摘The change characteristics and trends of the regional climate in the source region of the Yellow River, and the response of runoff to climate change, are analyzed based on observational data of air temperature, precipitation, and runoff at 10 main hydrological and weather stations in the region. Our results show that a strong signal of climate shift from warm-dry to warm-humid in the western parts of northwestern China （Xinjiang） and the western Hexi Corridor of Gansu Province occurred in the late 1980s, and a same signal of climate change occurred in the mid-2000s in the source region of the Yellow River located in the eastern part of northwestern China. This climate changeover has led to a rapid increase in rainfall and stream runoff in the latter region. In most of the years since 2004 the average annual precipitation in the source region of the Yellow River has been greater than the long-term average annual value, and after 2007 the runoff measured at all of the hydrologic sections on the main channel of the Yellow River in the source region has also consistently exceeded the long-term average annual because of rainfall increase. It is difficult to determine the prospects of future climate change until additional observations and research are conducted on the rate and temporal and spatial extents of climate change in the region. Nevertheless, we predict that the climate shift from warm-dry to warm-humid in the source region of the Yellow River is very likely to be in the decadal time scale, which means a warming and rainy climate in the source region of the Yellow River will continue in the coming decades.
基金Key Program of National Natural Science Foundation of China,No.51639005Central Public-interest Scientific Institution Basal Research Fund of China,No.CKSF2019214/HL,No.CKSF2019411/HL。
文摘To understand the non-equilibrium morphological adjustment of a river in response to environmental changes,it is essential to(i)accurately identify how past conditions of water and sediment have impacted current morphological adjustment of the river,and(ii)establish a corresponding simulation for non-equilibrium conditions.Based on discharge and suspended sediment concentration(SSC)as well as 82 cross-sectional data items for the Huayuankou-Lijin reach of the Lower Yellow River in the period 1965-2015,the process of adjustment of the geometry of the main channel(area,width,depth,and geomorphic coefficient),and its responses to changes in discharge and SSC for different reaches are statistically analyzed.Following this,a delayed response model(DRM)of the geometry of the main channel subjected to variations in discharge and SSC is established using a multi-step analytical model,with the discharge and SSC as the main controlling factors.The results show that the area,width,and depth of the main channel decreased initially,then increased,decreased again,and finally increased again.These features of the geometry of the channel were positively correlated with the 4-year moving average discharge and negatively with the 4-year moving average SSC.The geomorphic coefficient for the Huayuankou-Sunkou reach exhibited a trend of decrease,whereas that of the Sunkou-Lijin reach decreased initially,then increased,decreased again,and finally increased again.Except for the Huayuankou-Gaocun reach in 1965-1999,the coefficient was negatively correlated with the 4-year moving average discharge and positively with SSC.The simulated values of the morphological parameters of the main channel for all sub-reaches obtained using the DRM agreed well with the measured values.This indicates that the DRM can be used to simulate the process of response of the cross-sectional geometry of the main channel to variations in the water and sediment.The results of the model show that the adjustment of the geometry of the main channel was affected by the discharge and the SSC at present(30%)as well as for the previous 7 years(70%).The proposed model offers insights into the mechanism whereby past water and sediment influence the current morphological adjustment of the river,and provides an effective method for predicting the magnitude and trend of the geometry of the main channel under different flow conditions.
文摘黄河流域山西段是重要的生态屏障区,明晰生态系统服务权衡/协同强度的时空格局,对生态保护及经济协调发展具有重要意义。本文基于生态系统服务和权衡的综合评估模型(Integrated Valuation of Ecosystem Services and Tradeoffs,InVEST)量化生态系统服务供给量和需求量,通过均方根偏差(Root Mean Square Deviation,RMSD)量化生态系统服务权衡强度,利用结构方程模型(Structural Equation Model,SEM)分析权衡强度的驱动因素。结果表明:(1)2000—2020年产水(Water Yield,WY)和土壤保持服务(Soil Conservation,SC)、产水和固碳服务(Carbon Sequestration,CS)供给权衡强度呈上升趋势,产水和土壤保持服务、产水和固碳服务需求协同强度呈下降趋势。(2)除产水服务在2020年供给—需求权衡强度大于0,2000—2020年产水、土壤保持和固碳服务的供给—需求权衡强度均小于0。(3)生态系统服务权衡/协同强度主要受自然因素影响,蒸散发对产水和土壤保持服务、产水和固碳服务供给权衡具有促进作用,对产水服务供给—需求权衡具有抑制作用;草地面积占比对产水和固碳服务供给权衡及产水和土壤保持服务需求协同具有抑制作用,对固碳服务供给—需求权衡具有促进作用;降水对产水和固碳服务需求协同及土壤保持服务供给—需求权衡具有抑制作用,对产水服务供给—需求权衡具有促进作用。(4)社会经济因素对生态系统服务权衡/协同强度具有次要作用,人口密度对产水和土壤保持服务需求协同具有促进作用,而对产水服务供给—需求权衡及固碳服务供给—需求权衡具有抑制作用。因此,在制定流域综合管理决策时应考虑生态系统服务权衡/协同强度的空间特征和驱动因素的差异性。
