济南市历城区地下水数值模拟与预测

为充分利用地下水资源,在调查研究济南市历城区地下水补径排条件和水文地质的基础上通过GMS中MODFLOW模块建立历城区浅层孔隙水地下水数值模型,并采用PEST模块进行渗透系数调整以达到全局最优。利用识别检验后的模型预报不同地下水增采方案下5年后的地下水流场及典型长观孔水位动态变化。结果表明:在现状浅层地下水开采量的基础上增采50%以内,即3.195万m~3/d,可以在不造成地下水位持续下降的情况下最大程度地开发利用当地浅层地下水资源,实现经济快速发展。     

张家川水源地渗流井允许开采量的数值模拟计算

在分析渗流井的结构与水流特征的基础上,通过引入等效渗透系数,结合当地地质、水文地质条件,构建渗流井取水的“渗流-管流”耦合模型,用于神木县张家川傍河水源地渗流井取水工程。确定水源地的布井方式与开采方案,计算水源地的平、枯水期允许开采量。结果得出：干水期允许开采量为35500 m3/d,枯水期允许开采量为11800 m3/d。     

龙湖周边机井开采对地下水流影响的数值模拟

人工湖、库和河流等将改变区域水文循环过程,特别是地表水与地下水交换关系。本文对郑州市规划的龙湖入渗水利用和龙湖周边机井布设方案进行比较分析。龙湖水体形成后,湖区与周围地下水位的2.5m落差将使湖水大量入渗补给地下水,大范围抬升湖区周围地下水位,龙湖周围低洼处将有发生盐碱化的危险,威胁到紧靠龙湖的西部国家森林公园和规划中的东北部生态回廊绿地。本文利用美国地质调查局(USGS)颁布的三维地下水数值模型(MODFLOW),模拟不同湖底防渗措施和机井开采方案下龙湖周围地下水位变化以及龙湖入渗量,对龙湖周边布井方案可行性和降低地下水效果加以分析和比较。     

张家港暨阳湖湖底沉积物渗透系数的现场测定

在湖水与地下水相互作用的定量研究中 ,湖底沉积物的渗透系数是极其重要的参数之一。湖底沉积物渗透系数的传统测定方法主要为实验室分析法。该方法不能进行渗透系数的现场测定。竖管测定法可现场测定湖底沉积物的渗透系数。在张家港暨阳湖已开挖的湖区约 0 .3km2 的范围内进行了 2 9个点的野外现场测定。其垂向渗透系数的平均值为 2 .76× 10 -7cm/s。暨阳湖湖底沉积物的渗透性等级为极微透水     

陕北南梁白豹地区地下水合理开发利用方式研究

建立地下水的合理开发利用模式,对能源基地建设及缓解其水资源紧缺状况十分重要。在分析南梁白豹地区的地下水开采条件的基础上,选择了典型地区建立了三维地下水流概念模型和数值模型。通过模拟计算不同单井开采量、不同井间距开采方案作用下的降落漏斗形态,对该区内地下水资源的合理开发利用方式进行了分析研究,结果表明,在该区内地下水开采井应布设在较大的河谷区,以线状井排方式开采,以截取河流排泄量为开采量,地下水线状开采强度以不超过(0.02～0.03)×104m3/(d·km)为宜。     

智利Santiago谷地上部含水层地下水可持续开采量评价

近十年来，智利Santiago地区的地下水使用量在显著地增长，因此需要准确评价Santiago谷地上部含水层的地下水供水能力。为了确定水的可持续开采量，进行了该含水层特性的研究。利用最近48年不同开采方案下的补给资料，应用数值模型模拟了水位埋深。利用这些地下水水位数据，通过拟合时间系列模型和交叉理论确定了地下水水位概率分布函数，并评价了开采量。应用这些信息，能够评估可持续开采量不能满足地下水供水要求的风险，90％保证率下的可持续开采量仅占要求水量的67％，并且，所得到的结果表明该方法能够确定地下水的保证率。     

龙湖周边机井开采对地下水流影响的数值模拟

人工湖、库和河流等将改变区域水文循环过程，特别是地表水与地下水交换关系。本文对郑州市规划的龙湖入渗水利用和龙湖周边机井布设方案进行比较分析。龙湖水体形成后，湖区与周围地下水位的 2．5m落差将使湖水大量入渗补给地下水，大范围抬升湖区周围地下水位，龙湖周围低洼处将有发生盐碱化的危险，威胁到紧靠龙湖的西部国家森林公园和规划中的东北部生态回廊绿地。本文利用美国地质调查局（USGS）颁布的三维地下水数值模型（MODFLOW），模拟不同湖底防渗措施和机井开采方案下龙湖周围地下水位变化以及龙湖入渗量，对龙湖周边布井方案可行性和降低地下水效果加以分析和比较。     

应用解析法确定傍河水源地地下水开采方案

合理设计开采方案对傍河水源地地下水资源开发具有重要意义。以德惠典型傍河地下水水源地为研究区,在查明研究区水文地质条件的基础上,以管井为例,运用解析法确定了最佳开采方案和水源地地下水允许开采量,并对最佳开采方案的合理性和可靠性进行了分析。结果表明,当开采井沿河流呈直线形单排布井方式,井数为12眼,井河距离为200 m,井间距离为150 m,单井开采量为2 960 m3/d,总开采量为35 520 m3/d时,取水保证程度较高,面对河流突发性污染具有一定的抵御能力,不会对区域水环境和其他用户造成较大影响。     

输油管泄露地下水污染模拟及防控管理方案比选

以云南某炼油厂区内地下水为研究对象,通过分析其水文地质条件,结合钻孔水位资料,建立水文地质模型。选取石油类作为预测因子,采用GMS软件建立地下水水流场模型和溶质运移模型,计算在(156)d内石油类的迁移过程,并对比3种抽出处理法防控管理方案,选取最优方案。研究结果表明：石油持续泄露156 d时JC02监测到污染物,结合经济、人力等因素方案(2)为最优。     

地下水安全开采量的概念与评价方法研究

本文回顾了地下水安全开采量概念的产生与发展过程,综述了可持续开采量、允许开采量和安全开采量的内涵与差异,在此基础上,提出满足地下水的资源供给、生态环境维持、地质环境稳定和可持续开发利用能力4个功能条件下的地下水安全开采量概念.将安全开采量的评价方法分为单一约束型和耦合约束型两大类,提出一种基于水均衡和地下水动力学相结合的评价方法,并对安全开采量研究趋势进行了展望,为地下水的安全开采方案研究与动态管理提供技术支撑.     

Hydrological processes of adsorption,sedimentation, and infiltration into the lake bed during the 2004 urban flood in Dhaka city,Bangladesh

The urban flood of Dhaka city in September 2004 is a result of heavy rainfall (341 mm a day or more than 600 mm in 5 days). In addition to the local rainfall, elevated water levels in the surrounding rivers may have affected the flood duration by bank filtration. Two lakes, Banani and Gulshan, in the mid of the city are the part of general storm water retention system in Dhaka. Flood water runs through the lakes acting as channels to the pumping station downstream. A tank model is used in this study to describe the total drainage process with the hydraulic geometry and resistance laws to derive cross-sections and friction factors of the quasi-uniform flows. Assuming the dissolved matters of the flood water was of similar composition as in the lake sediments, the process was a combination of adsorption and sedimentation. Lake sediment samples collected in March 2004 show an anomaly of chromium which may reflect the previous 1998 flood, and there may be a diffusive leakage from the source area to the adjacent zones. Further evidence of infiltration process is seen in records of diurnal thermal stratification of Lake Banani. It responds to only heavy rainfalls over 100 mm/day, and the fact means that infiltration to the groundwater is rather intermittent.     

内蒙古河套平原塔尔湖地区湖泊成因

内蒙古五原县塔尔湖地区发育一系列湖泊,与当地干旱气候形成鲜明的对比,湖泊成因机制对河套地区第四纪水文地质、气候环境研究具有重要意义。对色尔腾山山前—塔尔湖湖泊—黄河沿线不同水体样品进行水化学测试后,利用Gibbs模型投影显示湖泊采样点主要落在蒸发-浓缩端元和岩石风化端元的过渡带,而远离大气降水作用带,地下水更靠近岩石风化端元,说明湖泊接受地下水补给,蒸发强烈;Piper三线图显示山前泉水以HCO3—Ca型为主,河套平原地下水以HCO3—Na、Cl—Na型为主,黄河水为HCO3—Na型,湖泊以Cl—Na型为主,说明塔尔湖地区地下水与湖泊存在水力联系,HCO3—Na型地下水经过蒸发浓缩作用转变成了盐度更高的Cl—Na型湖泊,导致盐分的聚集;地下水可溶性固体总量(TDS)自北向南由262 mg/l快速增加至2 296 mg/l,而湖泊TDS先升后降,最后小于地下水TDS,最大值在塔尔湖地区北部,为1 213 mg/l,说明湖泊还受现代黄河补给,地下水TDS变化满足山前—盆地的水文地质模型。塔尔湖地区的湖泊既可以发育于古河床亚相也可以发育于堤坝亚相,且湖泊呈零星分布,与古河道形成的牛轭湖特征不吻合,从而基本排除湖泊为古黄河残留的可能;潜水面之上的河流相沉积物由于风蚀作用被切穿,导致地下水出露,补给湖泊,从而推断塔尔湖地区湖泊主要为风蚀湖。     

敦煌月牙泉湖水位持续下降原因及对策分析

在分析月牙泉湖水文地质条件的基础上，依据实际调查资料和前人研究成果，定量分析了月牙泉湖水位持续下降的原因，认为地表水开采量的不断增加和水资源利用率的不断提高所引起的区域性地下水位持续下降是月牙泉湖水位下降的主要原因，超采地下水所引起的储存资源的减少是导致月牙泉湖地下水位下降的次要原因。遏止月牙泉湖水位继续下降并逐步回升的关键是增加湖区上游地下水的补给量和减少党河灌区开采量，为此提出了农业节水和引哈济党二种治理方案，但就月牙泉湖水位恢复速度和时间及取得的社会、生态及经济效益而言，引哈济党方案优先。     

Interactions of artificial lakes with groundwater applying an integrated MODFLOW solution

Artificial lakes (reservoirs) are regulated water bodies with large stage fluctuations and different interactions with groundwater compared with natural lakes. A novel modelling study characterizing the dynamics of these interactions is presented for artificial Lake Turawa, Poland. The integrated surface-water/groundwater MODFLOW-NWT transient model, applying SFR7, UZF1 and LAK7 packages to account for variably-saturated flow and temporally variable lake area extent and volume, was calibrated throughout 5 years (1-year warm-up, 4-year simulation), applying daily lake stages, heads and discharges as control variables. The water budget results showed that, in contrast to natural lakes, the reservoir interactions with groundwater were primarily dependent on the balance between lake inflow and regulated outflow, while influences of precipitation and evapotranspiration played secondary roles. Also, the spatio-temporal lakebed-seepage pattern was different compared with natural lakes. The large and fast-changing stages had large influence on lakebed-seepage and water table depth and also influenced groundwater evapotranspiration and groundwater exfiltration, as their maxima coincided not with rainfall peaks but with highest stages. The mean lakebed-seepage ranged from ~0.6 mm day^?1 during lowest stages (lake-water gain) to ~1.0 mm day^?1 during highest stages (lake-water loss) with largest losses up to 4.6 mm day^?1 in the peripheral zone. The lakebed-seepage of this study was generally low because of low lakebed leakance (0.0007–0.0015 day^?1) and prevailing upward regional groundwater flow moderating it. This study discloses the complexity of artificial lake interactions with groundwater, while the proposed front-line modelling methodology can be applied to any reservoir, and also to natural lake interactions with groundwater.     

Using multiple environmental methods to estimate groundwater discharge into an arid lake (Dakebo Lake,Inner Mongolia,China)

It is important to have both a qualitative and quantitative understanding of the hydraulic exchange between groundwater and surface water to support the development of effective management plans for sustainable use of water resources. Groundwater is a major source of surface-water recharge and plays an important role in maintaining the integrity of ecosystems, especially within wetlands in semi-arid regions. The Ordos Desert Plateau of Inner Mongolia (China) is a vulnerable ecosystem that suffers from an extreme lack of water. The hydraulic exchange between groundwater and lake water in Dakebo Lake (the largest of hundreds of lakes on the Ordos Desert Plateau) was evaluated using multiple environmental methods. Continuous monitoring of the groundwater and lake-water levels indicated that the lake was recharged vertically by groundwater. Application of hydrodynamic and temperature tracing methods to the western side of the lake indicated that the rate of groundwater discharge to the lake was about 2?×?10^?6 to 3?×?10^?6 m/s in spring, summer, and autumn, but that there was no recharge in winter because the hypolentic zone (HZ) was frozen. Mixing ratios of groundwater and lake water in the HZ, estimated from the ¹⁸O and ²H ratios, showed that there were spatial variations in the hydrodynamic exchange between groundwater and lake water within the HZ.     

Tracing groundwater discharge in a High Arctic lake using radon-222

In the High Arctic, groundwater fluxes are limited by the presence of continuous permafrost, although it has been hypothesized that there may be localized groundwater flow and hydraulic connectivity beneath large lakes, due to the presence of taliks, or large regions of unfrozen ground. However, due to the logistical difficulty of employing seepage meters and piezometers in deep, ice-covered lakes, relatively little is known about groundwater discharge to polar lakes. One method of assessing groundwater discharge is through the use of geochemical tracers. We conducted a pilot study to quantify groundwater discharge into a High Arctic lake using dissolved radon gas as a geochemical tracer. Lake water was collected in 15 L polyvinyl chloride (PVC) bags with minimal atmospheric interaction from a 25-m deep lake near Shellabear Point, Melville Island, Northwest Territories, Canada. Sample bags were aerated through a closed water loop for 60 min to allow sufficient radon to equilibrate in a coupled air circuit. Radon in air concentrations were measured on a Durridge RAD7 portable alpha spectrometer. The field trial in a remote setting and separate tests with groundwater samples collected from a temperate site demonstrate the utility of the methodology. The limited results suggest that radon levels in the lower water column are elevated above background levels following nival melt in the surrounding watershed. Although these results are insufficient to quantify groundwater discharge, the results suggest subsurface flow may exist, and further study is warranted.     

基于遥感和GIS的喜马拉雅山科西河流域冰湖变化特征分析

受全球气候变暖的影响, 冰川退缩, 冰湖数量增多和面积增大被认为指示气候变化的重要依据, 冰湖面积增大导致其潜在危险性增大. 因此, 研究冰湖的变化对于气候变化和冰湖灾害研究具有重要意义. 基于Landsat TM/ETM+遥感影像采用人工解译的方法, 获取了喜马拉雅山地区科西河流域1990年前后、2000年和2010年的冰湖数据, 并对冰湖面积>0.1 km²且一直存在的199个冰湖的面积和长度变化进行对比分析. 结果表明: 科西河流域内面积>0.1 km²的冰湖的面积呈现增加趋势, 1990年冰湖面积为73.59 km², 2010年冰湖面积增加至86.12 km². 科西河流域内喜马拉雅山南北坡冰湖变化存在差异, 喜马拉雅山北坡变化较大的冰湖主要分布在海拔4 800~5 600 m之间, 而南坡变化较大的冰湖主要分布在海拔4 300~5 200 m之间; 喜马拉雅山北坡的冰湖有65%的冰湖表现扩张, 且扩张冰湖的面积主要是由冰湖在靠近终碛垅的一端基本不发生变化, 而仅在靠近冰川一端发生变化贡献的; 喜马拉雅山南坡的冰湖有32%的冰湖变化表现扩张, 且扩张的冰湖面积主要来自于冰面湖扩张. 在科西河流域内, 位于喜马拉雅山北坡的冰湖平均变化速度略高于南坡的冰湖平均变化速度.     

Geologically controlled bi-directional exchange of groundwater with a hypersaline lake in the Canadian prairies

Hypersaline lakes occur in hydrologically closed basins due to evaporitic enrichment of dissolved salts transported to the lakes by surface water and groundwater. At the hypersaline Lydden Lake in Saskatchewan, Canada, groundwater/lake-water interaction is strongly influenced by the geological heterogeneity of glacial deposits, whereby a highly permeable glaciofluvial sand/gravel deposit is underlain by glaciolacustrine deposits consisting of dense clay interspersed with silt/sand lenses. Pressure head distribution in a near shore area indicates a bi-directional flow system. It consists of topographically driven flow of fresh groundwater towards the lake in the sand/gravel aquifer and density-driven, landward flow of saline groundwater in the underlying glaciolacustrine deposits. Electrical resistivity tomography, and chemical and isotopic composition of groundwater clearly show the landward intrusion of saline water in the heterogeneous unit. The feasibility of bi-directional flow and transport is supported by numerical simulations of density-coupled groundwater flow and transport. The results suggest that the geologically controlled groundwater exchange processes have substantial influences on both inputs and outputs of dissolved minerals in hypersaline lakes in closed basins.     

中国湖泊分布特征及典型流域生态保护修复建议

湖泊是地球关键带的重要组成部分,是水循环、物质循环和能量循环的重要环节。为了解我国湖泊分布现状,依托中国地质调查局“生态地质调查工程”及其所属二级项目“全国地球关键带遥感地质调查”,利用Landsat8 OLI 等卫星影像数据,通过遥感解译等技术方法,识别了2018年我国境内(不包括香港、澳门与台湾地区)面积大于1.0 km²的湖泊2 780个,总面积78 727.9 km²; 研究统计并分析了我国各省/自治区、五大湖区、主要流域的湖泊数量、面积和分布特征; 针对典型区域的湖泊存在的生态问题进行分析,提出相关湖泊生态保护修复的相关建议。其中,北方农牧交错带湖泊大量萎缩干涸,主因是农业和畜牧业的发展,地下水超采严重,应着力减少地下水开采; 黄河流域人工湖建设存在无序发展、过度追求景观水面扩张等问题,应遵从水循环与水平衡自然规律,针对全流域水资源配置进行调控; 长江源区湖泊水面整体处于扩张状态,应以自然因素为主、人类活动干扰触发为辅,加强冻土变化过程以及主要河流的水生态、水环境监测,综合提高源区整体监测水平。研究成果为后续湖泊生态保护修复研究工作提供了参考。     

郑州市龙湖成湖方案研究

人工湖建设可能引起地下水位的抬升,将对周边生态环境造成影响,如部分河岸区的浸没、土壤次生盐渍化、地下水质恶化、影响湖周高层建筑物的地基承载力等。在分析人工湖渗漏问题基础上, 提出了在不采取防渗措施和采取防渗措施两种不同情况下的成湖方案, 并进行了防渗方案的优选。用地下水数值模型MODFLOW和优化模型MODMAN对处于黄河冲积平原地区拟开挖人工湖进行了数值模拟及优化。结果表明,在龙湖运行时,只要人工湖的渗漏量控制在一定范围内,辅之于相应的湖体周边的降水措施,就可有效避免各种环境问题的出现。