纳污河补排关系变化时污染物迁移规律研究

多环芳烃是危害较大的一种水体污染物,以菲为特征污染物,利用纳污河流和地下水系统模拟装置,对其在河流与地下水补排关系变化时的迁移过程进行了研究,以探索纳污河流与地下水间多环芳烃的迁移变化规律。采用Sufer软件分析了菲在地层中的迁移变化情况,并计算了其迁移速度,结果表明:模拟纳污河水补给地下水时,菲迁移速度缓慢,污染物扩散范围小,水平迁移速度为1.33 cm/d;模拟清洁地下水向河流排泄时,菲的水平迁移速度为1.67 cm/d,并在河流附近发生了短暂富集。     

Response of an Unconfined Aquifer Induced by Time Varying Recharge from a Rectangular Basin

An analytical solution is developed to predict spatio-temporal variation of the water table in a 2-D aquifer system which is receiving transient recharge from an overlying basin of rectangular shape. The transient recharge function is approximated by a number of line segments. Application of the solution is demonstrated with the help of an example problem.     

非饱和带土壤水分势能与水分运动

本文通过对非饱和带水分势能的研究,阐述了土壤水分势能的变化与水分运动的关系,分析了“零通量面”的产生发展及其在研究土壤水分运动中起到的作用     

黄河大堤非饱和土的强度特征及其稳定性分析

利用特制的非饱和土三轴仪对非饱和土强度进行了试验研究,指出：非饱和土体的抗剪强度随着含水量的不同而不同,含水量越小,土体的基质吸力就越大,抗剪强度亦越大;非饱和土的抗剪强度均高于饱和土的抗剪强度.利用简化的Bishop法对非饱和土进行了边坡稳定分析,结果表明：基质吸力影响非饱和土的强度,进而影响边坡的稳定.     

黄河大堤非饱和土土水特征曲线研究

利用改进的非饱和土三轴仪，对黄河大堤重塑非饱和土进行了试验研究，分析了其渗透特性，并选用Van Genuchten模型拟合了试样的土水特征曲线，对不同围压下的土水特征曲线进行了比较。结果表明：①随非饱和土含水量的增大，基质吸力减小，非饱和土的工程性质向弱性变化；②在高含水量下，基质吸力随含水量变化的变化幅度很小，在低含水量(天然含水量)下，基质吸力随含水量的增大而迅速减小；③对某一类土而言，在低吸力下土的基质吸力主要随含水量而变化，在高吸力下其大小除取决于含水量外还受黏粒含量、矿物成分等因素的影响；④相同体积含水量的土壤的基质吸力随着围压的增大而减小，相同基质吸力的土壤的含水量随围压的增大而增大。同时指出，对于黏性较强、有机质含量较高的黄河大堤非饱和土的土水特征曲线，还需要进一步研究。     

Response of an Unconfined Sloping Aquifer to Constant Recharge and Seepage from the Stream of Varying Water Level

This paper presents analytical solution of one-dimensional linearized Boussinesq equation characterizing unsteady groundwater flow in an unconfined aquifer, overlying an impervious downward sloping bed. At one end, the aquifer is in contact with a constant water level and at the other end; water level is rising exponentially from an adjoining stream. The aquifer also receives constant or cycle of time-varying vertical recharge. Analytical expressions for hydraulic head and flow rate in the aquifer are obtained by solving the seepage model using Laplace transform. The expressions derived here can explain sudden rise or very slow rise in the stream water related to sloping or horizontal beds and are represented under asymptotic case. Response of a short and long aquifer to the variation in bed slope, recharge rate and rise rate of the stream water is illustrated with the help of numerical examples. The sensitivity of the flow rate is also analyzed with respect to various parameters.     

黄河下游大堤饱和-非饱和土渗流分析

针对现状条件下黄河大堤处于饱和-非饱和状态的事实,利用饱和-非饱和土系统的二维渗流模型对黄河大堤进行了渗流分析,结果表明:①浸润线瞬变位置在水位变化初期变化较快,随着时间的推移逐渐变慢;②等势线从饱和区向非饱和区扩展,说明在等势线间的水头差作用下,饱和区和非饱和区内都有水的流动;③由堤防顶部到底部,压力水头逐渐由正值变到负值,坝中央等压线几乎与浸润线平行;④流速矢量开始时垂直于地面,逐渐向堤内偏转,在坝中央部分平行于浸润线,在坝趾位置几乎垂直于坝趾.且浸润线上、下皆存在流速矢量.     

Design of Managed Aquifer Recharge for Agricultural and Ecological Water Supply Assessed Through Numerical Modeling

The Walla Walla Basin, in Eastern Oregon and Washington, USA, faces challenges in sustaining an agricultural water supply while maintaining sufficient flow in the Walla Walla River for endangered fish populations. Minimum summer river flow of 0.71 m³/s is required, forcing irrigators to substitute groundwater from a declining aquifer for lost surface water diversion. Managed Aquifer Recharge (MAR) was initiated in 2004 attempting to restore groundwater levels and improve agricultural viability. The Integrated Water Flow Model (IWFM) was used to compute surface and shallow groundwater conditions in the basin under water management scenarios with varying water use, MAR, and allowable minimum river flow. A mean increase of 1.5 m of groundwater elevation, or 1.5 % of total aquifer storage, was predicted over the model area when comparing maximum MAR and no MAR scenarios where minimum river flow was increased from current level. When comparing these scenarios a 53 % greater summer flow in springs was predicted with the use of MAR. Results indicate MAR can supplement irrigation supply while stabilizing groundwater levels and increasing summer streamflow. Potential increase in long-term groundwater storage is limited by the high transmissivity of the aquifer material. Increased MAR caused increased groundwater discharge through springs and stream beds, benefiting aquatic habitat rather than building long-term aquifer storage. Judicious siting of recharge basins may be a means of increasing the effectiveness of MAR in the basin.     

Effect of Land-Use Change and Artificial Recharge on the Groundwater in an Arid Inland River Basin

The spatial-temporal variability of groundwater in an inland basin is very sensitive to human activity. This study focused on groundwater changes in the Alagan area within the Tarim Basin, China, with the aim of analyzing the effects of land-use change and artificial recharge on the response characteristics of groundwater. The distributed hydrological model MIKE SHE was introduced for modeling the influence of land use and artificial recharge on groundwater. Based on the runoff variation of this area, we selected three periods to simulate and analyze the response of groundwater. The results of land-use change indicated that there were significant changes from 1980 to 2000. The changed region accounted for 11.93 % of the total area, and the low coverage grasslands showed the greatest reduction. The simulation of hydrological processes before artificial recharge showed that the groundwater depths differed greatly with land-use types. Response analysis of groundwater to artificial recharge showed that the regions in which groundwater decreased were mainly distributed in grassland and bare land. Moreover, spatial autocorrelation coefficients indicated positive spatial autocorrelation of groundwater depths, but these began to reverse in 2010. Overall, land use and artificial recharge have a great influence on the time and spatial distribution of groundwater. Artificial recharge has played a positive role in improving groundwater conditions, but did not change the decreasing trend in time and space. The adaptation of environment to the decrease of groundwater presents as degradation. Groundwater conditions could be improved to some extent by the artificial recharge, but its change seems to be an irreversible process. Overall, this response study provides insight into estimations for exploration of water resources in arid areas.     

Evolution of the Water Table in a Finite Aquifer Due to Transient Recharge from Two Parallel Strip Basins

Understanding the dynamic response of phreatic aquifers due to recharge is most important for the proper management of ground-water systems. In this paper an analytical solution is developed to describe the water-table fluctuation in a finite aquifer system due to transient recharge from two parallel strip basins. Application of the solution in the prediction of spatiotemporal variation of the water table and in the sensitivity analysis of the effects of various controlling parameters on the water-table fluctuation is demonstrated with the help of an example problem.     

Simulation of Groundwater Flow in an Unconfined Sloping Aquifer Using the Element-Free Galerkin Method

Water Resources Management - Numerical simulation of groundwater flows in real aquifers has been commonly based on Finite Difference (FDM) and Finite Element Methods (FEM). These mesh-based methods...     

Impact of Treated Wastewater Reuse on Agriculture and Aquifer Recharge in a Coastal Area: Korba Case Study

Treated wastewater (TWW) reuse has increasingly been integrated in the planning and development of water resources in Tunisia. The present study aimed the evaluation of the environmental and health impact that would have the reuse of TWW for crops direct irrigation or for the recharge of the local aquifer in Korba (Tunisia). For this purpose water analyses were carried on the TWW intended for the aquifer recharge and on underground water of this area. As for underground water before recharge, no contamination by organic matter or heavy metals is shown but high salinity, nitrate, potassium and chloride concentrations are detected. The bacteriological analyses show the occurrence of faecal streptococcus, thermo-tolerant coliforms, total coliforms and E coli, but absence of salmonella. These results indicate that this water is not suitable for irrigation worse still for drinking purpose. The monitoring of TWW pollutants has demonstrated that oxygen demands (COD and BOD) do not exceed the Tunisian standards for TWW used in agriculture (NT 106.03) except for August when samples reach high values (COD = 139 mg O₂ L^− 1, BOD = 34). It is also the case for temperature, electrical conductivity (EC), salinity and pH. Heavy metal concentrations are under the detection limit. The determination of nutrients shows relatively low concentrations of nitrates, nitrites and orthophosphate (the maxima in mg L^− 1 are respectively 6.6, 5.6 and 0.92) whereas the potassium levels are high (up to 48.8 mg L^− 1) and the ammonia levels very high, reaching 60.6 mg L^− 1. As for bacteriological pollution, while no salmonella and intestinal nematods are detected, high concentrations of total coliforms, thermo-tolerant coliforms, faecal streptococci and E. coli are analysed. Consequently, the better use of TWW in this region would be the use of infiltration basins for the recharge of the deteriorated aquifer by TWW. It would give the opportunity to better the quality of the TWW reaching the groundwater by an additional treatment for bacteriological and suspended solid (TSS) contaminants while being an alternative water for the aquifer recharge and a coastal barrier against seawater intrusion.     

Identification of the Saline Zone in a Coastal Aquifer Using Electrical Tomography Data and Simulation

A novel approach that borrows methods commonly used in environmental geophysics was developed for obtaining the estimates of the aquifer parameters. Specifically, estimates of hydraulic conductivity were obtained from field measurements of the electrical resistivity while accounting for the karsticity of the geological formations in the area of study. Geophysically determined hydraulic conductivity estimates were introduced to a 3-D groundwater numerical simulator (Princeton Transport Code – PTC) to compute the hydraulic heads distribution of the area of interest. The calibration of the numerical model was obtained matching the hydraulic-heads predicted by the simulator with the hydraulic-heads measured at specific well locations. Simulated hydraulic-heads were used with the Chyben-Herzberg equation to approximate the position of the sharp freshwater/saltwater interface of the base of the water supply aquifer. The existence of the faults impacts the groundwater flow and the distribution of the freshwater/saltwater interface.     

西福河橡胶坝充排水系统的选型设计

以西福河橡胶坝充排水系统的选型和布置设计为例,分析了橡胶坝设计中,充排水系统选择上常见的问题,提出了初步的解决方案,为橡胶坝进一步的推广应用提供参考。     

含水率对黄河大堤非饱和土强度的影响

利用改进的非饱和土三轴仪,对不同含水率条件下的非饱和土抗剪强度进行了试验。试验结果表明：①非饱和土存在基质吸力,并且基质吸力随着含水率的减小而增大。②非饱和土的抗剪强度均高于饱和土的抗剪强度,且抗剪强度随含水率的不同而不同：含水率越小,土体的基质吸力就越大,抗剪强度亦越大;反之,含水率越大,非饱和土的基质吸力就越小,抗剪强度亦越小。③含水率趋于饱和时,非饱和土的抗剪强度逐渐接近于饱和土的抗剪强度。     

走航式ADCP与转子式流速仪流量测验对比分析

运用走航式ADCP对辽河盘山水文站断面进行中高水流量测验,并与流速仪法测量相比较,对测验数据进行分析计算．可以看出该型ADCP适合于盘山站流量测验,发挥出了此仪器稳定性好、精度高、速度快、成果可靠等特点。     

Predictive Simulation of Flow and Solute Transport for Managing the Salalah Coastal Aquifer, Oman

A three-dimensional numerical model for flow and solute transport was used for the management of the Salalah aquifer. The model calibration procedures consisted of calibrating the aquifer system hydraulic parameters by history matching under steady and transient conditions. The history of input and output of the aquifer were reconstructed in a transient calibration from 1993 to 2005. Predictive simulation of the aquifer was carried out under transient conditions to predict the future demand of groundwater supply for the next 15 years. A baseline scenario was worked out to obtain the piezometric surface and salinity distribution for the “business as usual” conditions of the aquifer. The “business as usual” scenario was predicted and simulated for the period 2006 until 2020. The effectiveness of seven management options was proposed and assessed for comparison with the “business as usual” conditions. The established simulation model was used to predict the distribution of the piezometric surface, salinity distribution, and mass balance under the proposed scenarios for the prediction period 2006–2020. The scenarios were: (1) relocate Garziz and MAF farms far from the freshwater zone, (2) suspend the abstraction of grass production for 4 months a year, (3) changes in agricultural and irrigation system patterns, (4) establish a desalination plant, (5) combined scenario (1 + 4), (6) combined scenario (1 + 3), and (7) combining all scenarios (1 + 2 + 3 + 4). The result of the simulation shows that the best effective option in terms of aquifer groundwater levels is the fifth proposed scenario and the sixth proposed scenario is the best effective option in terms of aquifer groundwater salinity situation during the next 15 years. This project suggested the application of scenario 6 as it is environmentally sound in terms of sustainable management. A prediction has been made which shows that further actions have to be taken within the next two decades to ensure continuity of the municipal water supply. The management scenarios are examined in the case of the Salalah coastal aquifer using groundwater simulation, which can also be applied to other regions with similar conditions. The established model is considered a reasonable representation of the physical conditions of the Salalah plain aquifer, and can be used as a tool by the water and environmental authorities in the management of the groundwater in the region.     

基于生物习性和流量变化的南水北调西线调水河道的生态需水估算

提出一种基于生态保护对象的生活习性和流量变化的河道生态需水(EIFR)估算方法,简记为习变法(LiHaflo-Va)。方法通过建立流量变化与生物习性的定量联系,确定主要生态保护对象生活习性关键月份,既具有水文学方法的简便优势,又能尽可能多地考虑生物学特性,能较好地解决资料缺乏地区的生态需水估算问题。EFIR的计算包括两部分,对关键月,EIFR为该月中值流量与该月的流量变异系数的乘积。对其它月份,EIFR为90%超过概率流量与全年各月流量变异系数最小值之乘积。应用该法计算了南水北调西线一期工程包括达曲、泥曲、色曲、杜柯河、玛柯河和阿柯河等6条调水河流的生态需水。结果表明,河道内多年平均状态每年需保持的水量占多年平均年径流量的比例在达曲至少为24.7%,泥曲为46.4%,色曲为21.7%,杜柯河为21.6%,玛柯河为15.0%,阿柯河为15.7%。该比例系数基于研究区生态保护对象的生活习性,是流域的客观反映,可以作为制定工程最大可调水量的依据。计算表明,在工农业生产及居民生活用水大约占多年平均年径流量的6%的条件下,6条河多年平均意义上每年最大可调水总量为41.87×108m3,占6条河多年平均总径流量(60.5×108m3)的69.2%。