The research of three-dimensional numerical simulation of groundwater-flow: taking the Ejina Basin, Northwest China as example

Water is a primary controlling factor for economic development and ecological environmental protection in the inland river basins of arid western China. And it is groundwater, as the most important component of total water resources, that plays a dominant role in the development of western China. In recent years, the use-ratio of surface water has been raised, the groundwater recharge rate from surface water has been reduced, and groundwater has been exploited on a large scale. This has led to the decline of ground-water levels and the degradation of eco-environments in the Heihe watershed. Therefore, the study on the change in groundwater levels in recent years, as well as simulating and predicting groundwater levels in the future, have become very significant for im-proving the ecological environment of the Heihe River Basin, to coordinate the water contradiction among upper, middle and lower reaches of Heihe River Basin and to allocate the water resources. The purpose of this study is to analyze the groundwa-ter-level variations of the Ejina region based on a large scale, to develop and evaluate a conceptual groundwater model in Ejina Basin, to establish the groundwater flow model using the experimental observation data and combining Modular Three-Dimensional Groundwater Flow Model (MODFLOW) and GIS software, to simulate the regional hydrologic regime in re-cent 10 years and compare various water-delivery scenarios from midstream, and to determine which one would be the best plan for maintaining and recovering the groundwater levels and increasing the area of Ejina oasis. Finally this paper discusses the pos-sible vegetation changes of Ejina Basin in the future.     

Characterization of groundwater in the Ejina Basin, northwest China: hydrochemical and environmental isotopes approaches

To characterize the groundwater in the Ejina Basin,surface and groundwater samples were collected in May and October of 2002.On-site analyses included temperature,electrical conductance(EC),total alkalinity(as HCO 3) by titration,and pH.Chemical analyses were undertaken at the Geochemistry Laboratory of the Cold and Arid Region Environmental and Engineering Institute,Chinese Academy of Sciences,Lanzhou,China.The pH of the groundwater ranged from 7.18 to 8.90 with an average value of 7.72,indicating an alkaline nature.The total dissolved solids(TDS) of the groundwater ranged from 567.5 to 5,954.4 mg/L with an average of 1,543.1 mg/L and a standard deviation of 1,471.8 mg/L.According to the groundwater salinity classification of Robinove et al.(1958),47.4 percent of the samples were brackish and the remainder were fresh water.The ion concentration of the groundwater along the riverbed and near the southern margin of the basin were lower than those farther away from the riverbed.The groundwater in the study area was of Na +-HCO 3 type near the bank of the Heihe River and in the southern margin of the basin,while Na +-SO 4 2-Cl type samples were observed in the terminal lake region.In the desert area the groundwater reached a TDS of 3,000-6,000 mg/L and was predominantly by a Na +-Cl chemistry.Br/Cl for the water of Ejina Basin indicates an evaporite origin for the groundwater with a strongly depleted Br/Cl ratio(average 0.000484).The surface water was slightly enriched in Br/Cl(average 0.000711) compared with groundwater.The calculated saturation index(SI) for calcite and dolomite of the groundwater samples range from 0.89 to 1.31 and 1.67 to 2.67 with averaged 0.24 and 0.61,respectively.About 97 percent of the groundwater samples were kinetically oversaturated with respect to calcite and dolomite,and all the samples were below the equilibrium state with gypsum.Using isotope and hydrochemical analyses,this study investigated the groundwater evolution and its residence time.The groundwater content was mainly determi     

The response of Caragana microphylla seedlings to water table changes in Horqin Sandy Land, China

This paper focuses on the growth response of Caragana microphylla seedlings to changes of artificially controlled water table in Horqin Sandy Land, China. Monitoring results of soil water content shows that soil moisture is closely correlated to groundwater depths. Soil volumetric water increased rapidly when close to water sources and finally stabilized in a saturated state. The soil moisture trend of CK(control) increased gradually at 0–50 cm of soil depth then decreased to 4% below 50 cm soil depth. C. microphylla can adapt to different soil environments by changes in ecological and physiological characteristics. By comparing the ecological characteristics of C. microphylla seedlings at various water tables, we found that a shallow water table of 40 cm depth inhibited seedling growth because of weak ecological characteristics. A groundwater depth of 120 cm was more advantageous for plant height and canopy growth of C. microphylla seedlings. During the first two years, the most suitable water depth for root biomass was 120 cm, and 180 cm for root length. The growth of vertical roots is positively correlated with groundwater depth, and root thickness is the determinate factor for root biomass while the fine root is the determinate factor for root length. A thick root would grow much more in a natural drought environment while access to ground water promotes the growth of fine roots.     

社会生态补偿标准测算方法(英文)

Ecological compensation is a hot subject in academic studies, and the determina-tion of the spatial allocation of compensation payments is a key point in the research of eco-logical compensation. There are two kinds of thoughts in the determination of regional spatial allocation at present: "evaluation of ecological construction cost" and "evaluation of ecosystem services value". This paper analyzes the relationships between social ecological compensation and regional socio-economic development, and establishes two econometric models with the data of 2007 from various provinces in China. Through these models, the impacts of geographical endowments on the regional socio-economic development in various provinces are analyzed from the social justice viewpoint and the concept of "equivalent value of geographical endowments" (EGE for short) is proposed. This paper analyzes the application prospect of EGE in the policy making of regional ecological compensation. The results showed that: (1) the implementation of social ecological compensation is not only an effective guarantee for each region to obtain the equal rights of survival, development and decent environment, but also an essential assurance to the coordinated, balanced and sustainable development among various regions; (2) the regional difference in geographical endowments is an important factor affecting the regional spatial variation of socio-economic development. Therefore, geographical endowments are important bases for the determination of the spatial allocation of compensation payments in social ecological compensation; (3) based on the EGE, the government can determine the spatial allocation of social ecological compensation scientifically, and avoid the "sweeping approach" phenomenon in the policy making process of ecological compensation.     

地下水位变化对干旱区植被盖度的影响及其空间变异特征

Sampling and testing are conducted on groundwater depth and vegetation coverage in the 670 km^2 of the Sangong River Basin and semi-variance function analysis is made afterwards on the data obtained by the application of geo-statistics. Results showed that the variance curve of the groundwater depth and vegetation coverage displays an exponential model. Analysis of sampling data in 2003 indicates that the groundwater depth and vegetation coverage change similarly in space in this area. The Sangong River Basin is composed of upper oasis, middle ecotone and lower sand dune. In oasis and ecotone, influenced by irrigation of the adjoining oasis, groundwater level has been raised and soil water content also increased compared with sand dune nearby, vegetation developed well. But in the lower reaches of the Sangong River Basin, because of descending of groundwater level, soil water content decreased and vegetation degenerated. From oasis to abandoned land and desert grassland, vegetation coverage and groundwater level changed greatly with significant difference respectively in spatial variation. Distinct but similar spatial variability exists among the groundwater depth and vegetation coverage in the study area, namely, the vegetation coverage decreasing (increasing) as the groundwater depth increases (decreases). This illustrates the great dependence of vegetation coverage on groundwater depth in arid regions and further implies that among the great number of factors affecting vegetation coverage in arid regions, groundwater depth turns out to be the most determinant one.     

The calculation and analysis of ecological footprints,diversity and development capacity of China

The ecological footprint of China’s provinces is calculated in this paper.In general,China’s development is not sustainable because its ecological footprint is beyond its bio-capacity.The sustainability status of each province in China is presented.Ulanowicz’s developmnt capacity formula was introduced to discuss th relation ship of development and ecological footprint’s diversity.The diversity of ecological impacts is related to the efficiency with which an economy uses the source and sink services of the environment and,in this efficiency with which an economy uses the source and sink services of the environment and ,in this view,should be a factor in economic output.Development capacity,calculated from the ecological footprint and its diversity,is used to examine the relationship o economic output with the structure of the ecological footprint.China and its provinces are presented as a case study to investigate this relationship.The analysis shows that footprint capacity is significant in prdicting economic output.Increasing the ecological footprint’s diversity is presented as another way to increase development capacity.     

考虑地下水可持续开采约束条件的海河流域水资源优化配置（英文）

This study applies a hydroeconomic optimization method for water resources management in the highly water stressed Haihe River basin. A multi-objective, multi-temporal deterministic hydroeconomic optimization model has been built to quantify the economic trade-offs and reveal "minimum cost strategies" when reducing groundwater abstraction to sustainable levels. A complex basin representation, with ～140,000 decision variables is formulated where each decision variable represents a flow-path from a water source to a sink. Available water sources are runoff generated by the sub-basins upstream the nine major surface water reservoirs, the inter-basin transfers from Yellow River and South to North Water Transfer Project(SNWTP) and the natural groundwater recharge to the three main groundwater aquifers. Water demands, i.e. sinks, are aggregated for each model sub-basin in categories of the major agricultural users, domestic, industrial and ecological water demands. Each demand is associated with a curtailment cost and groundwater abstraction with a pumping cost. Groundwater overdraft is constrained in each model scenario, ranging from unlimited overdraft in the plain area groundwater aquifer to sustainable abstractions over an 8-year period. Inflow upstream Yuqiao reservoir, and the inter-basin transfers from SNWTP and Yellow River are identified as the water resources with the highest increase in average shadow prices when limiting groundwater overdraft. An increase in inflow shadow prices of 37.5% indicates that these water sources will be most valuable if sustainable groundwater abstraction should be achieved. The shadow prices of water sources reveal when and where in the Haihe River basin users are curtailed if water resources are managed in the most optimal way. Average shadow prices of 1.6 yuan/m3 for all surface water sources in the sustainable abstraction scenarios shows that overdraft can be avoided by curtailment of users with a willingness-to-pay ≤1.6 yuan/m3. The shadow prices of the existing surface water res-ervoirs represented in the model shows that no costs can be saved from expanding their capacities. Finally, the cost of achieving sustainable groundwater abstraction with present water resource availability is found to be minimum 8.2 billion yuan/year.     

Ecological risk assessment and ecological security pattern optimization in the middle reaches of the Yellow River based on ERI+MCR model

The middle reaches of the Yellow River represent an important area for the protection and development of the Yellow River Basin. Most of the area of the river basin is within the Loess Plateau, which establishes it as a fragile ecological environment. Firstly, using high-resolution data of land use in the watershed from the past 30 years, landscape ecological risk(LER) sample units are defined and an ecological risk index(ERI) model is constructed. Kriging interpolation is used to display the LE...     

中国省域间生态地租分异特征及其影响因素(英文)

Ecological land rent is the excess profit produced by resource scarcity, and is also an important indicator for measuring the social and economic effects of resource scarcity. This paper, by calculating the respective ecological land rents of all the provinces in China for the years 2002 and 2007, and with the assistance of the software programs ArcGIS and GeoDA, analyzes the spatial differentiation characteristics of ecological land rent; then, the influencing factors of ecological land rent differentiation among the provinces are examined using the methods of traditional regression and spatial correlation analysis. The following results were obtained: First, ecological land rent per unit of output in China shows stable distribution characteristics of being low in the southwestern and northeastern provinces, and high in Hebei and Henan provinces. There is also an increasing tendency in the central and western provinces, and a decreasing one in the eastern provinces. In general, the spatial distribution of ecological land rent per unit of output in China is quite scattered. Second, the total ecological land rent shows significant spatial aggregation characteristics, in particular the provinces in China possessing high total amounts of ecological land rent tend to be adjacent to one another, as do those with low total amounts, and the spatial difference characteristics of the eastern, central and western provinces are distinguished. The Bohai Rim, Yangtze River Delta and Pearl River Delta are shown to be highly clustering regions of total ecological land rent, while the western provinces have very low ecological land rent in terms of total amount. Third, population distribution, economic level and industrial structure were all important influencing factors influencing ecological land rent differentiation among provinces in China. Furthermore, population density, urbanization level, economic density, per capita consumption level and GDP per capita were all shown to be positively related to total ecological land rent, which indicates that spatial clustering exists between ecological land rent and these factors. However, there was also a negative correlation between ecological land rent and agricultural output percentage, indicating that spatial scattering exists between ecological land rent and agricultural output percentage.     

辽宁省生态足迹地理分布及其可持续发展分析

This paper presents the detailed results and analyses on the ecological footprints and bio-capacities of the individual cities and the province as a whole for the year 2001, providing a clear picture of sustainability for the province. Results show that the ecological footprints of most cities in Liaoning exceeded their respective bio-capacities, incurring high ecological deficits. The ecological deficit of the province as a whole was 1.31 ha/cap. Those cities with resources extraction and/or primary material-making as their major industries constitute the “ecologically black band“, whose ecological deficits ranged from 2.45 to 5.23 ha/cap, the highest of all cities in the province. Fossil energy consumption was the major source of footprint amounting to 1.63 ha/cap at the provincial level,taking up 67.3% of the total. For cropland, modest ecological surpluses occurred in Jinzhou, Tiding,Huludao, and Panjin while modest ecological deficits in Dalian, Benxi, Fushun, and Dandong, resulting in an overall surplus for the province. Liaoning had a certain level of surplus in fishing ground (water area), mainly distributed in the coastal cities of Dalian, Panjin, Huludao, Yingkou, Jinzhou, and Dandong. Most cities had a small ecological deficit in pasture and all had a small ecological surplus in forest. The eco-efficiency, expressed as GDP value per hectare of footprint, exhibits high variations among the cities, with the highest (Shenyang) more than 10 times the lowest (Fuxin). Cities with manufacture, high-tech, and better developed service industries had high eco-efficiency, while those with resources extraction, primary material-making, and less developed service industries had low eco-efficiency. Based on the components and geographical distribution of ecological footprint, strategic policy implications are outlined for Liaoning‘s development toward a sustainable future.     

Dynamical variations in groundwater chemistry influenced by intermittent water delivery at the lower reaches of the Tarim River

The water of Bosten Lake was released to lower reaches of the Tarim River for 5 times from 2000 to 2002. The changes of total dissolved solid (TDS) and the major ions (SO2-4, Cl-, Na+, Ca2+, Mg2+ and HCO-3) were analyzed during this period. It was found out that TDS and the concentrations of the major ions initially and quickly increased and then decreased, but finally increased again. These changes were different at different distances from the river, which indicated that the groundwater changes relied on the distance from the river. In addition, the salt in groundwater was only diluted but not removed by the water. It was suggested that ecological measures should be sought to really promote the quality of the groundwater at the lower reaches of the Tarim River.     

塔里木河下游地下水化学特征对生态输水的响应

结合2000~2002年塔里木河下游5次生态输水过程,通过对沿河40眼地下水监测井采集的水化学资料的分析表明：塔里木河下游地下水化学特征随五次间歇性生态输水发生明显变化。地下水化学对输水的响应表现为初期、中期和后期三个阶段：初期,地下水化学成分中的主要离子含量和矿化度都明显上升;中期逐步下降;输水后期又逐步上升。通过对地下水盐运移机理以及生态输水后地下水化学变化特征的分析得出,单一河道输水方式不如双河道,甚至多河道输水更有利于生态的恢复,另外,生态输水只是对地下水中盐分浓度起到了稀释作用,只有采取一系列工程和管理措施才能使下游水质真正好转。     

新疆塔里木河下游断流河道输水对地下水变化的影响分析

结合2000～2002年以来塔里木河下游间歇性输水后地下水变化的监测数据．用回归分析的方法对输水后地下水位动态响应变化过程进行分析,揭示输水量与地下水的响应范围之间的关系。结果表明：在横向上．随着向塔河生态输水次数和输水量的增加．地下水的响应范围逐渐扩大．但随远离输水河槽中轴线,响应程度减小．地下水位的抬升幅度减弱;纵向上,输水河段上游区段地下水位响应范围最大,中游区段次之,下游区段较小。在第二次输水过程中,靠近河岸地下水位出现急剧上升,而在第三次输水过程中,地下水的响应范围则有巨幅增加．输水量与输水持续时间与地下水位变化有着密切关系。     

塔里木河下游生态输水河道两侧区域地下水运动规律研究

根据塔里木河下游断流区域含水层水文地质特征及其实际输水过程中河水对浅层地下水的补给规律,建立了塔里木河下游绿色走廊生态输水河道附近区域地下水运动的一维非稳定流模型,并通过在整个输水过程中流量与水位两种边界条件相互转换的一种方法求解模型。最后应用上述模型分析了间歇性输水条件下塔里本河下游断流河段河道两侧地下水位恢复状况,为输水生态效益的定量评价及其今后输水工作的决策提供理论基础。     

塔里木河下游地下水变化动态分析

由十塔里木河下游地下水位不断下降,而来水量却连年减少,与20世纪50年代相比平均下降了4～6m。随着大面积发展灌溉农业,排水洗盐改良土壤进程加快,相应地排入塔里木河的咸水也大大增加,塔河下游地下水水质也发生相应的变化。通过对塔里木河下游地下水变化动态以及来水量、农业灌溉对地下水的分析,也对沙漠化发展和分布对地下水的响应关系进行了探讨。     

塔里木河下游生态输水对沙漠化逆转的影响

塔里木河下游是我国沙漠化最严重的地区之一。由于人类不合理的资源开发, 导致320km河道断流、大面积湿地消失、地下水位大幅度下降、天然植被全面衰败, 沙漠化程度加重。作者结合塔里木河下游生态输水和近3a的实地监测资料, 分析输水前后塔里木河下游典型地区沙漠化程度的变化, 并就生态输水对塔里木河下游沙漠化逆转的影响进行了讨论。结果表明, 生态输水后, 河道附近地下水位大幅度抬升, 植被种类和盖度明显增加, 部分地区沙漠化得到逆转。从实现逆转的沙漠化土地的空间分布看, 在纵横两个方向上表现出明显的变化规律, 在纵向上表现为上游土地沙漠化逆转的强度和范围较下游大; 在横向上, 表现为距输水河道越近变化越明显的特点。考虑到输水影响范围较小, 建议对现行的输水方式和输水规模进行适当调整。     

塔里木河下游生态需水估算

量化生态需水是流域水权分配的重要依据。以塔里木河下游大西海子水库至尾闾台特玛湖段为研究区,借助湿周法计算了该段河道内最小生态需水量,并基于2009年和2010年河段地下水分布特征,计算沿线河道两岸各1 km范围地下水恢复至目标埋深(5～4 m)的地下水恢复量,采用潜水蒸发法和面积定额法估算了沿线天然植被生态需水量。结果表明：（1）塔里木河下游大西海子-台特玛湖河道内年最小生态需水量为1.455×108 m3;（2）以5年为恢复期限,确定该河段地下水埋深恢复至5～4 m的年恢复需水量为0.608×108～1.466×108 m3;（3）取潜水蒸发法和面积定额法计算结果均值,确定研究区天然植被生态需水量为1.042×108 m3;（4）综合考虑,塔里木河下游大西海子-台特玛湖年生态需水总量为3.105×108～3.963×108 m3。     

塔里木河的水资源利用与生态保护

分析塔里木河1956~2000年间水资源开发利用过程中的生态与环境问题时发现,进入90年代,塔里木河源流区的山区来水量增加了约10.9 %,但是,源流区补给塔里木河干流的水量却减少了18.83 %。三源流灌区用水量的增加导致塔里木河干流区的来水量不断减少,而塔里木河下游来水量的大幅度减少,则是因塔里木河干流上中游耗水量的增加引起。塔里木河干流自身沿程水量变化对下游水量减少的影响,远大于塔里木河上游三源流来水变化对下游造成的影响;塔里木河下游来水量的锐减,造成下游河道断流321 km,尾闾湖泊干涸,地下水位下降,天然植被衰败,沙漠化过程加剧。     

近20 a塔里木河下游输水对生态环境的影响

塔里木河下游是新疆生态环境问题比较突出的地区。为改善该地区恶化的生态环境,国家自2000年起向塔里木河下游实施了18次以生态建设和环境保护为目的的生态输水工程。近20 a来,塔里木河下游地下水位随输水次数增加呈不断上升趋势,生态植被不断修复,生态环境逐步好转。尤其是2017年实施第18次生态输水后,下输水量及其影响范围取得较大突破,引起社会高度关注。通过近20 a的断面来水监测资料,从水量、水质、地下水变化、植被恢复等方面,初步分析输水对生态环境的影响。同时,对前人研究的成果进行梳理和延展,使其对今后塔里木河下游的生态调度和科学管理起到指导作用。经分析得出以下结论：（1）虽然生态输水量基本都补给了生态植被和河道两侧的地下水,但持续性输水才是保证下游脆弱的生态环境稳定好转的根本途径。（2）输水使下游生态环境得到改善,现生态植被正在恢复,地下水位逐步抬升,地下水质明显好转。（3）采用汛期输水和间歇机动式调度,可使输水效益达到最大化。     

人类活动干预后的塔里木河水资源持续利用问题*

人类活动的加剧,使干旱区河流原有的水文状态发生了很大变化.而如何持续利用变化后的地表水资源,是保证干旱区持续发展的前提之一.该文分析了人类活动对新疆塔里木河流域水文干预的后果,认为人类活动使河流下游径流量减少,水量的时空分布改变,径流规律趋于复杂化.指出,维持一定的河流水量,整治河道和改变用水模式是持续利用塔里木河水资源的保证.