The Jiuquan Basin, with area of 6,800 square kilometers, located in the arid northwest of China, is a vital part of the Hexi Corridor. Investigating its groundwater circulation model is essential for understanding regional hydrogeological processes, sustainable water resource management, and ecological protection. This study, building upon previous research, utilizes hydrogeological surveys, hydrogeochemical analysis, isotope tracing (δD and δ18O) with sample size of 439, and radiocarbon dating (14C) with sample size of 45 to evaluate the groundwater flow systems and groundwater age distribution. Results reveal that groundwater primarily originates from meltwater from the Qilian Mountains and atmospheric precipitation, flowing from south to north. The central basin exhibits slower circulation and older groundwater, while the groundwater in the Heihe River mainstream and the Beida River Basin was relatively young due to the favorable conditions for recharge and discharge. The local meteoric water line (LMWL) is defined as δD = 6.02 × δ18O- 2.5. Based on isotopic and age data, the basin is divided into several secondary groundwater flow systems (SGFS). This work contributes valuable insight into arid-zone hydrodynamics and supports ecological and water management strategies in the Jiuquan Basin.

This study investigates the chemical characteristics, formation, and sources of inorganic nitrogen (IN) of shallow groundwater across the Sanjiang Plain, aiming to enhance drinking water safety management and pollution control. A total of 167 groundwater and 27 surface water samples were collected for constituents and isotopes (H-2 and O-18). The hydrogeochemical characteristics showed that the major type is HCO3- CaMg, with low total dissolved solids and a neutral to weak alkaline nature. Rock weathering processes govern the hydrochemical composition of groundwater. Hydrogen and oxygen stable isotopes analyses revealed that precipitation serves as the main water source. In alluvial areas, oxidative conditions lead to the enrichment of NO3-N concentrations, with sewage, manure, and fertilizers being the primary IN sources. In lacustrine areas, intensive rice cultivation results in reductive conditions and strong denitrification processes, causing the loss of NO3-N and leaving NH4-N as the dominant IN form. Organic matter mineralization is likely a more significant contributor to NH4-N concentrations than ammonium fertilizers. These findings provide valuable information for further research on natural sources and groundwater pollution in areas with similar hydrogeological conditions.

The Muji spring travertines, located in the Muji Basin in the eastern Pamirs Plateau, represent a typical spring deposit found on plateaus that is characterized by arid and semi-arid climatic conditions. However, its formation mechanisms remain poorly understood. This study aims to explore the recharge processes of the spring, the sedimentary environment, and the genetics of Muji spring travertines through a comparative analysis of conventional hydrochemistry, H-O stable isotope analysis of both spring and river water, and petrographic observation, as well as in situ analysis of major and trace elements present in calcite within travertines. The basin is surrounded by mountains with a topography that facilitates groundwater convergence within it. Carbonate-bearing strata are extensively developed around the basin, which serves as a crucial material foundation for travertine development. It infiltrates underground through fractures and faults, interacting with carbonate rocks to produce significant amounts of HCO3−, Ca2+, and Mg2+. The observed range of isotopic compositions (δ2H, −102.27‰ to −96.43‰; δ18O, −14.90‰ to −14.36‰) in water samples suggests that their primary origin was from glacial and snowmelt sources. The concentration of HCO3− in spring water samples exhibits significant variability, with the highest value being 1646 mg·L−1, which deviates significantly from the typical composition of karst groundwater. During its migration, groundwater undergoes the dissolution of gaseous CO2 derived from deep metamorphic processes, leading to variable degrees of mixing with geothermal groundwater containing elevated concentrations of dissolved components that enhance the dissolution potential of carbonate rocks. Eventually, upwelling occurs along the Southwestern Boundary Fault of Muji, resulting in the formation of linear springs characterized by CO2 escape. The Muji laminated travertines exhibit distinct white and dark laminae, and radial coated grains consisting of micritic and sparry layers. Chemical composition analyses reveal significant differences in the trace and rare-earth element composition, as well as the Mg/Ca ratio, of the two types of travertines. Specifically, the micritic laminae of the pisoid (Mg/Ca = 0.019; Sr = 530 × 10−6; Ba = 64.6 × 10−6) and the dark laminae of the laminated travertine (Mg/Ca = 0.014; Sr = 523 × 10−6; Ba = 48.1 × 10−6) exhibit generally higher Mg/Ca ratios and Sr, Ba contents than the neighboring sparry laminae (Mg/Ca = 0.012; Sr = 517 × 10−6; Ba = 36.6 × 10−6) and white laminae (Mg/Ca = 0.006; Sr = 450 × 10−6; Ba = 35.6 × 10−6). The development of laminated travertines and radial coated grains here is attributed to periodic changes in groundwater recharge induced by seasonal temperature fluctuations, as evidenced by the structural characteristics of the two types of travertines and the trace element analysis of different layers. Algae play a role in forming the dark laminae of laminated travertines and the micritic laminae of pisoids.

The dynamics of the water table is an important control on the connection of groundwater to land surface processes. Agricultural intensification has resulted in a significant decline in the groundwater table in the eastern part of the Sanjiang Plain, China. This decline may have caused significant changes in groundwater recharge and circulation, with implications for natural resources and the environment. In this study, hydrogeological (hydraulic head observations, unsaturated zone lithology), hydrochemical (major ions, redox-sensitive parameters, metasilicic acid) and isotopic (δD and δ18O) data was interpreted through spatial analysis, scatter plots and multivariate statistical methods to construct a conceptual model of shallow groundwater circulation in the Sanjiang Plain following decades of agricultural development. The distribution of the hydraulic head clarified the direction of groundwater flow, and the stable isotope compositions confirmed that shallow groundwaters mainly originated from precipitation and river water. Shallow groundwater levels and enriched groundwater isotopic compositions along the Songhua River and in the upper reaches of the Naoli River indicated some influence by evaporation. The relatively high nitrate concentration and coupling of isotope characteristics showed that sandy unsaturated zones enabled groundwater to be easily influenced by land surface processes. In the Jiansanjiang District and Naolihe Basin, the clayey unsaturated zones inhibited the connection between groundwater and the surface. Redox-sensitive components indicated that the groundwater features a reducing environment and weak groundwater update capability. If the current rate of exploitation continues in the Jiansanjiang District, the groundwater levels will continue to decline.

Being a famous hometown of vegetables in China, Shouguang City has a long history of vegetable cultivation and is a comprehensive national commodity base for vegetables and fruits. In recent decades, with the expansion of agricultural production, the use of pesticides is increasing. Although organochlorine pesticides (OCPs) have been banned, there are still some residues in soil, groundwater and other media. The study on the migration of the OCPs in soil and groundwater is of great importance for the maintenance of food security. Using methods of hydrogeological survey, laboratory testing and numerical simulation, the spatial distribution characteristics, sources and pollution degree of OCPs in soil and groundwater were analyzed, and the migration and transformation of OCPs in soil–groundwater was dynamically simulated and predicted. The study showed that there were many kinds of OCPs residual in the soil environment. The hexachlorocyclohexane (HCHs) in the topsoil of the study area were mainly due to the use of lindane, and the main source of dichlorodiphenyltrichloroethane (DDTs) in soil was the use of DDTs in history. The contents of HCHs, DDTs and hexachlorobenzene in the topsoil of the study area were at a low level, while the content of endosulfan metabolite endosulfan sulfate was comparatively higher. In recent years, the content of organochlorine pesticides in soil has generally decreased. The indexes of OCPs in groundwater can meet the Standards for Drinking Water quality of China. It was predicted that the HCH pollutants would mainly be distributed in Gucheng Street, Shangkou Town, and its south area where the concentration exceeds 3 ng/L exceeds that of 240 km2. DDT pollutants would mainly be distributed in the east and north of Shouguang City, where the concentration beyond 0.6 ng/L exceeds that of 200 km2. Endosulfan sulfate pollutants would mainly be distributed in the Gucheng Street Office, Shangkou Town, and its south area where the concentration exceeds 1.5 ng/L will exceed that of 150 km2. Hexachlorobenzene (HCB) pollutants would mainly be distributed in Fengcheng in the west of Shouguang City and Nancha River in the northeast, where the concentration exceeds 0.2 ng/L will exceed that of 200 km2. The study enriched the monitoring data of OCPs in agricultural planting areas and provided reference for source analysis, migration prediction, and pollution prevention of OCPs.

The ecological environment of the northwest inland basin is fragile. The groundwater environment is a crucial influencing factor for the harmonious and sustainable development of the local social economy and the ecological environment. It is significant to investigate the groundwater chemical characteristics, water quality, and the factors that influence groundwater chemistry for groundwater resources development and construction of the ecological environment. In this study, the Jinta Basin (JB), Gansu Province, was the selected study area. Three hundred and fifty groups of shallow groundwater samples in the JB were collected and analyzed, and the characteristics and controlling factors of groundwater were determined by using Piper diagram, Gibbs plot, ion ratio relationship, and factor analysis. Single index evaluation method, comprehensive evaluation method, and entropy-weighted water quality index method were used to evaluate the water quality of the groundwater. The results indicated that the shallow pore water in the JB was alkaline as a whole; the ranges of total dissolved solids (TDS) in the Beidahe River impact area (BIA), the transition area (TA) and the Heihe River impact area (HIA) were 328.4–12,400 mg·L−1, 372.70–3774.0 mg·L−1, and 366.30–75,200.0 mg·L−1, respectively; the major anions and cations of the shallow pore water were SO42−/Cl− and Mg2+/Na+, respectively. The Piper diagram illustrated that the hydrochemical type of groundwater in the JB were mainly HCO3·SO4-Mg type, SO4·HCO3-Mg type, SO4-Mg·Na type, SO4·Cl-Na·Mg type, and Cl-Na type. The overall water quality of the shallow groundwater in the JB was relatively poor, mainly falling into Class IV-V water quality. Sulfate, total hardness (TH), TDS, chloride and sodium were the main influencing factors of water quality. The chemical characteristics of groundwater in the JB were controlled by a variety of natural factors, including rock weathering, evaporative concentration, and cation exchange, among which the main controlling factors of shallow pore water were leaching, evaporative concentration and anthropogenic activities (contribution rate of 73.94%), and sulfate rock and carbonate rock dissolution (contribution rate of 14.91%).

The Sanjiang Plain is an important base of commodity grain production and contains lots of marsh wetlands in China. In the past 60 years, with the continuous increase of farmland area and the adjustment of planting structure, the decline of wetland and groundwater level has attracted great attention, whether the over-exploited groundwater is controversial. The remote sensing image data from 1956 to 2019 were selected to the analyze the evolution process characteristics of wetland and farmland using single land use dynamic degree. Based on the simultaneous measurement data in 1980 and 2019-2021 and the national groundwater monitoring project data, the influence of wetland reclamation on the groundwater level was explored. The results show that: (1) From 1956 to 2019, the marsh wetland presented a decreasing trend, while the dry land showed a trend of increasing first and then decreasing, and the paddy field had a trend of increasing first and then stabilizing. Sanjiang Plain was characterized by “wetland turning into dry land” with the area of 2.36×104 km2 from 1956 to 1996, while it presented “dry land turning into paddy field” with the area of 1.15×104 km2 from 1996 to 2019. (2) The decrease in groundwater level in the area of 36 546 km2 in the Sanjiang Plain from 1980 to 2021 was less than 5 m, and more than 10 m in the eastern area with 3 669 km2. The groundwater in the Jiansanjiang area is being over-exploited. (3) Compared with the groundwater level in the dry season in 1980, the groundwater depression cone area was 3 669 km2 in 2021 with the depth of 10 m as the standard, which was 269 km2 larger than that in 2019, and slightly expanded to the northeast direction. (4) In 2019, it was difficult to reach the natural regulation of “abundance to make up for deficiency” under the condition of heavy rainfall in the Jiansanjiang reclamation area, and the groundwater storage decreased by 5.81×108 m3. The results of this study provide a foundation for the study on regional water balance and are of great significance to the scientific understanding of the rational development and utilization of water and soil resources.

The arid endorheic basin of northwest China is characterized by rich land resources, water shortage, and a fragile ecological environment. The establishment of a credible coupling model of groundwater and surface water based on multi-source observation data is an effective means to study the change in basin water cycles and the sustainable utilization of water resources in the past and future. Based on the latest understanding of hydrogeological conditions, hydrology and water resource utilization data in the middle reaches of the Heihe River Basin (HRB), this paper constructs an up-to-date coupling model of surface water and groundwater to study the water balance change of the basin. The water resources data series under historical replay and CMIP5 climate model prediction are constructed to predict future changes in water resources. The study shows that, under the joint influence of natural conditions and human activities, the average annual recharge of groundwater in the study area from 1990 to 2020 is 17.98 × 108 m3/a, the average annual discharge is 18.62 × 108 m3/a, and the difference between recharge and discharge is −0.64 × 108 m3/a. The total groundwater storage is −19.99 × 108 m3, of which the groundwater storage from 1990 to 2001 was −17.52 × 108 m3 and from 2002 to 2020 was −2.47 × 108 m3. Abundant water from 2002 to 2020 in the basin significantly improved the loss of groundwater storage. Under the prediction of historical reappearance and the CMIP5 CNRM-CM5 model RCP4.5 and RCP8.5 pathways, the groundwater level of the Heihe River–Liyuanhe River inclined plain falls first because the HRB has just experienced a wet season and then rises according to future climate change. The groundwater level of the inclined plain east of the Heihe River and Yanchi basin decreases continuously because of the change in water cycle caused by human activities. The erosion accumulation plain is located in the groundwater discharge zone, and the water level is basically stable. Under the conditions of water resource development and utilization, the runoff of Zhengyixia hydrological station cannot meet the requirements of the “97 Water Dividing Plan” of the State Council in most years in the future, and the ecological and production water in the lower reaches of HRB cannot be effectively guaranteed. With the implementation of water-saving irrigation under the RCP4.5 and RCP8.5 scenarios, the runoff of Zhengyixia can meet the “97 Water Diversion Plan”. It is suggested to further improve the level of agricultural water savings in the middle reaches of the HRB and control the reasonable scale of cultivated land in order to reduce water consumption in the middle reaches of the HRB and implement sustainable utilization of water resources in the HRB.

Taking the Sanjiang Plain as an example, this paper selects typical profiles A-B along the groundwater flow direction. Based on the groundwater flow field in 1980 and 2019 dry seasons and the duration monitoring data of typical monitoring wells from 2018 to 2021, this paper applies GIS analysis, statistical analysis and comparative analysis methods to study the characteristics and causes of the difference in the dynamic changes of groundwater in the east and west directions in the Sanjiang Plain. The results show that: compared with 1980, the groundwater level in Jiansanjiang area has dropped 5-14m in total. The decline rate is reduced from 0.59m to 0.29m per year, and the groundwater level in the central and western plain area shows a small decline or upward trend. The groundwater regime in the central and western plain area is sensitive to artificial exploitation and atmospheric precipitation. The fluctuation range of groundwater level in the mainland can reach 9 meters, and that in Jiansanjiang area is mostly less than 1 meter. Influenced by the paleogeographic sedimentary environment, the characteristics of shallow surface "west sand and east clay" and the spatial differences of aquifer water richness are the main reasons for the significant inter annual and intra annual dynamic differences of groundwater in the east and west.

三江平原地下水开采量随着水稻种植规模快速扩张而大幅增加,2021年水位相对1980年下降5～12 m,是否因此引发地面形变甚至地面沉降成为社会关注的问题.采用二等水准测量方法和比拟法,分析研究了三江平原建三江垦区地下水位降落漏斗地面形变现状与发展趋势及危险性.研究表明,研究区50个二等水准测量点2019-2021年连续3期测量数据对比发现,地表垂向形变量整体较小(最大-18.00 mm,平均变化速率-4.6 mm/a).预测到2040年,地下水位降落漏斗中心水位埋深由2021年的19.88 m降至25 m左右,考虑到研究区"上粘下砂"的二元岩性结构,地下水位下降疏干的地层位于浅上部且厚度有限,地面沉降量仍较小,地质灾害发育程度弱、危险性小.本研究不仅回应了社会关切,也为进一步开展相关研究奠定了基础.

Temperature is an inherent property of groundwater.Groundwater temperature field and dynamic characteristics are objective manifestations of groundwater flow system.Based on multi-point, long series and high precision groundwater temperature monitoring data, the characteristics of shallow groundwater temperature distribution and dynamic type of water temperature in Jiuquan East Basin are studied, in order to reveal the relationship between the characteristics of shallow groundwater temperature field and groundwater flow system under the influence of human activities such as groundwater exploitation in northwest inland basin.The results show that the shallow groundwater temperature ranges from 9.33℃ to 20.77℃, and the average water temperature is 13.54℃.From the recharge area to the discharge area, the shallow groundwater temperature increases gradually along the direction of groundwater runoff, and the average groundwater temperature in January is higher than that in July.The comparison of different groundwater flow systems with similar circulation depth shows that the shallow groundwater temperature is negatively correlated with groundwater dynamic conditions.The average groundwater temperature of the water flow system with large surface water recharge and strong hydrodynamic conditions is lower, and that of the water flow system with small recharge and weak hydrodynamic conditions is higher.The temperature dynamics of shallow groundwater are affected by human activities such as natural groundwater circulation and groundwater exploitation.From groundwater recharge area to oasis area in the middle reaches and drainage area in the lower reaches, the temperature dynamic of shallow groundwater can be divided into four basic types, which are river recharge type, water temperature stability type, groundwater exploitation related type and sinusoidal fluctuation type respectively.

The mutual transformation of surface water and groundwater is an obvious feature of water cycle in arid inland basins in northwest China. Examination of the transformation mechanism is an important basis for the cognition of basin water cycle law and the sustainable management of water resources. In this paper, the Zhangye Basin and Yanchi Basin in the middle reaches of the Heihe River Basin in the arid inland river of northwest China are taken as the research areas, and the time-varying water balance model of the main channel of the Heihe River and the coupling numerical model of surface water and groundwater are established. The conversion mechanism of surface water and groundwater under the dual influence of long-term hydrological changes and human activities is studied, and the following understanding is obtained. (1) The recharge conditions change from linear recharge dominated by river leakage under natural conditions to linear recharge dominated by river and diversion channel leakage and surface recharge of infiltration in irrigation areas. The discharge conditions change from spring overflow and natural wetland discharge to spring overflow and groundwater exploitation. (2) The infiltration section and overflow section of the Heihe River in the Zhangye Basin are roughly bounded by the G312 Bridge, which is also called the turning point of surface water and groundwater transformation. The Yingluoxia-G312 bridge section is a suspended river leakage section, and the river infiltration recharge is mainly controlled by the actual amount of water entering the river. Among them, the infiltration recharge rate of the Yingluoxia-Caotanzhuang section is 43.34%. The river channel infiltration recharge and river channel flow can be expressed by the piecewise function in the Caotanzhuang-G312 bridge section. When the river channel flow is greater than (or equal to) and less than 3.7×108 m3 per month, it shows a power function relationship and a linear function relationship, respevtively. The G312 bridge-Zhengyixia section is the groundwater overflow section. The groundwater overflow amount of the G312 bridge-Pingchuan bridge section accounts for about 70% of the total overflow amount. The peak overflow occurs at about 6 km downstream the Gaoya hydrological station, and the single-length overflow amount can reach 0.46 m3/(s·km). (3) The study area is a relatively complete river-aquifer system, which has undergone continuous dry and wet hydrological changes in the past 31 years. The recharge and discharge conditions of groundwater and the transformation mechanism of surface water and groundwater have changed accordingly. The conversion between surface water and groundwater is the strongest in the Heihe-Liyuan River inclined plain in the middle of the Zhangye Basin. During the continuous dry period from 1990 to 2001, the water diversion in the irrigation area decreased year by year, and the recharge mainly caused by river channel infiltration and canal system leakage decreased at a rate of 0.06×108 m3/a. The increase of farmland irrigation area led to the increase of irrigation water, the obvious increase of groundwater exploitation, the decrease of groundwater level year by year, the cumulative decrease of storage amount by 5.80×108 m3, and the annual decrease of groundwater overflow amount by 0.13×108 m3/a. During the continuous harvest period from 2002 to 2020, the water diversion in the irrigation area decreased year by year, and the river infiltration showed an increasing trend. The total groundwater supply increased by 0.15×108 m3/a, the irrigation area continued to expand, and the agricultural irrigation exploitation increased accordingly. The increase in river infiltration was the dominant factor, and the groundwater levels continued to rise. The total storage increased by 5.42×108 m3, and the groundwater overflow increased by 0.06×108 m3/a. In short, the recharge and discharge conditions vary greatly, the groundwater storage decreases first and then increases, and the total amount of groundwater overflow changes gently, which reflects the huge storage function of the thick aquifer system in this area. (4) The groundwater level in the production period of the inclined plain located in the eastern part of the Zhangye Basin is in a continuous decline, which is due to the sharp decrease of excessive surface water development. The groundwater level in the Heihe erosion-accumulation plain is basically stable. Over the past 30 years, the groundwater level in the inclined plain of the Yanchi Basin has been in a state of continuous decline, which is caused by excessive groundwater exploitation due to immigration reclamation. (5) The natural suspended river infiltration section in the inland basin is a precious groundwater recharge channel. Whether in the continuous dry or wet period, the actual river flow is the key to the river leakage recharge. Protection of the upstream natural river and a certain actual river flow is the key to the sustainable management of water resources in the inland basin.

Rainfall and irrigation are important sources of recharge for shallow groundwater in the middle reaches of Heihe River . There is no mature monitoring method and empirical data for evaluating infiltration recharge by introducing empirical parameters for a long time. In this paper, artificial bromide tracer method is used to study groundwater infiltration under different irrigation conditions and different depths in the middle reaches of the Heihe River. The results show that under the condition of rainfall in the study area, the annual average transport distance of the peak content of bromine ion in the vadose zone is 21.25 cm, the annual average recharge is 11.93 mm, and the infiltration recharge coefficient is 0.1. Under the condition of large irrigation amount, the average annual migration distance of the peak content of bromine ion in the vadose zone is 86.51 cm, the average annual recharge is 148.7 mm, and the infiltration recharge coefficient is 0.16. Under the condition of small irrigation amount, the average annual migration distance of the peak content of bromine ion in the vadose zone is 46.35 cm, the average annual the downward zone of unidirectional infiltration of water in the unsaturated zone, which is generally suitable in the recharge is 53.81 mm, and the infiltration recharge coefficient is 0.07. Under drip irrigation, the average annual moving distance of the peak value of bromine ion content in the vadose zone is 41.72 cm, the average annual supply is 52.6 mm, and the infiltration recharge coefficient is 0.11. Artificial bromide tracers should be placed in northwest inland basin more than 3 m. The results can provide parameters for the evaluation of groundwater resources in the Heihe River Basin, which is of great significance for scientific understanding of groundwater resources and rational development and utilization in northwest inland basins.

In recent years, groundwater levels in parts of the Sanjiang Plain has continuously decreased, which attracts great attention from scholars and related departments. In order to find out the temporal and spatial evolution of the groundwater flow field in the Sanjiang Plain and reveal its main influencing factors, in this paper the ArcGIS interpolation analysis, grid algebraic operations, comparative analysis and other methods are used to analyze the 72 groups of data in the Sanjiang Plain in 1980 and 1092 groups of groundwater level data and 44 groups of national groundwater monitoring data in the same period in 2019 and 2020. The spatio-temporal evolution characteristics of the groundwater flow field in the Sanjiang Plain are ascertained, and the control effects of different influencing factors on the smooth evolution of groundwater are clarified. The results show that, compared with 1980, the groundwater levels of the Sanjiang Plain showed an overall decreasing trend. The groundwater levels of the western plain area cumulatively decreased by 1 to 5 m, with an area of 2.6×104 km2, and most areas of the eastern Jiansanjiang reclamation area fell greater than 5 m with an area of 1.17×104 km2. Among them, the area where the cumulative drop of groundwater levels is greater than 10 m is as high as 3 400 km2, and the average annual drop of groundwater levels is about 0.29 m. Groundwater exploitation causes the changes in the groundwater flow field, and the hydrogeological conditions of "West Sand and East Stick" promote the temporal and spatial evolution of the regional groundwater level decline. The continuous expansion of the scale of paddy fields has caused over-exploitation of groundwater. The shallow surficial clay layer blocks replenishment from rainfall infiltration, and the groundwater cannot achieve self-balance with abundance to compensate for the shortage, resulting in the continuous decline in groundwater levels in the Jiansanjiang Reclamation Area. The results of this research lay a foundation for further investigation of the groundwater change laws and current characteristics of the Sanjiang Plain, and also provide technical support for scientifically guiding the rational development, utilization and management of groundwater resources.

依据地下水流系统及化学平衡理论,运用Gibbs图、Gaillardet端元图、离子比值分析、水文地球化学模拟等方法,系统研究了鼎新谷地浅层地下水化学特征及控制机制.结果表明:1)研究区地下水化学类型主要为SO4·HCO3型、SO4·Cl型、SO4型、Cl型.2)地下水化学组分主要受岩石风化、蒸发浓缩作用控制,部分样品位于Gibbs图"回形镖"范围之外,表明发生了阳离子交换作用.3)大墩门-芨芨村-鼎新镇-航天镇一带地下水主要受蒸发岩、硅酸盐岩不协调风化作用控制,苇坑泉一带地下水受蒸发岩风化作用控制.4)在反向模拟的地下水流路径上,白云石、石膏、盐岩、芒硝、钾盐发生溶解,方解石沉淀,在下游区发生了 Ca2+、Mg2+阳离子交换作用.

The technology of injecting cement for the stratified well completion can provide a new rapid and high effective technology for the stratified well completion on a multi-layer hydrogeologic well. The problems of time-consuming, bad effect, unstable effect of sealing water, difficult construction and high failure rate of the stratified well completion for the stratum of fine grained or unstable drilling structure resulting from traditional methods of the stratified well completion are considered, and the technology of injecting cement for the stratified well completion is developed through laboratory tests and drilling construction. On the basic of the expounding principle and the process of the technology of injecting cement for the stratified well completion, the application example of the HQ56 hydrogeologic well from the stratified well completion, segment well-flushing and stratified pumping test of the hydrogeologic well is analyzed. The results show that application of the technology of injecting cement for the stratified well completion to seal water is reliable and the data from the stratified pumping test is accurate. The technology is especially suitable for the rapid stratified well completion on the stratum of fine grained or unstable drilling structure.

干旱内陆河出山径流及其影响因素分析对于流域水资源评价、流域经济生态安全保障具有重要意义.基于1960-2012年塔里木河流域“三源流”与黑河流域的出山径流、降水、气温资料及4个全球气象指数监测数据,采用小波分析方法研究了各水文气象要素的周期特征,以及流域出山径流对气象要素与气象指数的响应特征.结果 表明:(1)各水文气象因子多具有1～2个显著周期,周期多在2～7a尺度范围内.(2)叶尔羌河、黑河出山径流与流域降水分别在6～17a、2～16a周期上关系显著.各出山径流与流域降水、气温的多尺度共振周期性差异,反映了各径流来源构成及其与气象要素年际动态方面的差异.(3)各流域出山径流对气象指数的响应特征不同,这在显著时频域以及径流响应时滞等方面均有表现.此研究可为气候变化条件下干旱内陆河流域生态—水文过程响应及水资源管理提供依据.

研究黑河干流水资源的可持续利用问题,有助于促进中游盆地的科学用水,保障下游区域的生态稳定.黑河干流中游灌区由于过度引水,导致其正义峡下泄量偏离了国家97分水方案的调控目标.以中游盆地张掖、临泽和高台农灌区为主要研究对象,基于多目标多约束方程构建了水资源可持续利用规划模型.模型模拟表明,正义峡下泄量主要受莺落峡径流量、灌区引水量以及黑河大桥-正义峡段地下水溢出量等的影响与控制.模型预测显示,通过灌区节水措施降低灌溉定额,黑河干流水资源可以在支撑中游灌区现状灌溉面积用水量的同时,确保正义峡下泄量达到国家分水方案确定目标.多目标规划模型的研究结论,确立了中游盆地水资源可持续利用的用水方案,该方案将有效解决中游和下游水事矛盾,既可以保障中游人工绿洲经济发展,也可以保护下游生态环境.

以地下水水质检测数据为基础,结合历史水质资料,总结出包头市潜水的变化特征:潜水组分中变化最大的为F-和NO3-,超标率增幅达到445％和146％.2000-2011年水质总体较差,并有恶化的趋势.构建数学模型,预测极端状态下污染物在包头市某地区包气带垂直入渗速率,结果表明,一般情况污水入渗的地层饱和度在60％左右,污水点源渗入到潜水面的时间为0.01-0.11 d,面源渗入到潜水面的时间为0.2-0.41 d,该区域污染物到达潜水面的时间较短,潜水极易受到污染.

本文在区域水文地质和污染源调查的基础上,对榆林地区地下水有机污染进行初步分析.结果发现,该地区地下水有机污染具有检出种类多、检出率高、浓度低、超标率低的特点.地下水中检出的有机污染物共有18种,检出的16项有机污染物含量均低于《地下水质量标准》(GB/T14848-2007)三类水限值.潜水与承压水的检出率几乎相当,但潜水的检出项数高于承压水.不同区域有机指标的污染程度不同,定靖横油气田区＞神府矿区＞榆阳区.不同地貌类型的有机污染物检出率为黄土区(17.65％》河谷区(14.93％)＞平原区(11.11％)＞沙漠滩地区(8.60％).