青海省德令哈盆地拟建德令哈市第二水源地模拟分析

针对德令哈盆地平原区水文地质条件,建立地下水流数学模型,选用Processing Modflow集成系统对德令哈盆地内平原区极富水地段进行地下水数值模拟研究,并按设计开采量5.0×104m3/d对地下水水位进行预报,经模型验证预报结果可靠,水源地设计开采量是可行的,下游水环境与生态环境仍在可接受范围内。     

不冻泉应急水源地水文地质特征及开发利用研究

不冻泉一带赋存第四系松散岩类孔隙潜水和构造裂隙水两种地下水类型,可建立孔隙水和构造裂隙水类型水源地.受研究区水文地质条件的制约,孔隙水类型水源地仅适用于每年的5～9月份暖季丰水期,水质较好,开采便利,允许开采量为1.5×104m3/d,;构造裂隙水虽埋藏较深,但不受季节限制,水质较好,可供全年开采.针对该区水资源利用现...     

邯邢水文地质南单元岩溶地下水系统开发优化决策

在对邯邢水文地质南单元岩溶地下水系统进行定量优化分析的基础上 ,给出了该系统到 2 0 0 8年 12月底 ,地下水位标高约束在 95m和 85m时的最优开采量及其开采布局 ,论述了邯峰电厂一期工程水源地开采量保证程度及其增加二期工程水源地开采量的可行性。     

福建省龙岩盆地地下水资源评价及水资源供需平衡分析

本文在阐述龙岩盆地水文地质条件特征的基础上,依据已有的地下水长观资料,对龙岩盆地的地下水资源量进行评价,认为允许开采量约为27.9万m3/d,扣除岩溶地下热水允许开采量1.73万m3/d,实为26.2万m3/d;因此,在局部区域尚有8万m3/d的开采潜力。但根据全市近期和中长期的水资源供需平衡分析结果,到2010年时,岩溶地下水资源将不能满足全市的用水要求,必须另找出路。     

艾娜克铜矿水源地地下水允许开采量计算及影响评价

为保护阿富汗艾娜克铜矿一带地下水资源环境,同时在开采期间不发生危害性的环境水文地质问题,根据在阿富汗艾娜克铜矿一带进行的供水水文地质勘查成果及水源地稳定流抽水试验成果采用补偿疏干法对水源地的允许开采量进行计算并对水源地取水后对当地地质环境的影响程度进行评价,本水源地为山间河谷调节型水源地,本次研究确定的地下水资源储量1 255~28 m3/d,精度为探明的(B级)允许开采量。水源地开采运行后不会对周边产生危害性沉降,但是会对影响半径范围内的(北段1 240 m、南段1 860 m)居民生活生产用水造成不同程度的影响,需要采取相应的措施确保铜矿水源地正常开采运行。     

漳州地下热水资源评价方法浅析

原《漳州地热详查报告》以开采模数法计算基岩裂隙热水允许开采量7598.2m3/d作为C级储量,《漳州盆地地下热水动态监测报告》以开采模数法加中温区试验推断法计算水温≥40℃基岩裂隙热水允许开采量5153.3m3/d,此二数值与实际开采量加基坑降水量之和对比分析,均偏小,以大井法计算水温≥50℃的孔隙热水允许开采量作为C级储量更为可靠,按水位降深5.45m计,并经垂向、侧向补给量保证验算修正后,允许开采量10208.97m3/d。     

沧州市地下水允许开采量研究

针对沧州市第四系松散沉积层地下水开采所引起的地面沉降问题,以地面沉降为约束条件来研究其地下水允许开采量。在充分掌握研究区区域地质,工程地质和水文地质的基础上,概化出了研究区地下水开采与地面沉降的地质概念模型,建立了与之相适应的地下水开采与地面沉降耦合数学数值模型。在对模型识别验证之后,模拟计算了以地面沉降为控制目标的沧州市地下允许开采量。结果表明:在满足地面沉降控制目标条件下,沧州市地下水允许开采量最大为14819.5×104m3/a,最小为788.2×104m3/a。     

温州市区地下淡水应急水源地开发利用潜力评价

本文选取永强平原为温州市区地下淡水应急水源地,并对其承压水在应急状态下的可开采潜力进行了评价。结果表明,永强平原水源地淡水资源丰富,当水位下降到-25 m时,淡水可开采总量为16640.18×10~4m~3,可为市区供水862d;微咸水可开采总量为15662.37×10~4m~3,可为市区供水811d。结合城市空间规划和沉降中心,对第Ⅰ含水层淡水区进行了优化,优化后的可开采量为7386.20×10~4m~3,可为市区供应382d。目前优化区内仅有4眼水井,应急状态下可供给人口为14.5万,占市区人口的4.1%,需考虑新增开采井。水质上,区内铁、氨氮等含量超标,对短期应急供水影响不大,如长期供水时需采用相关装置处理。     

福建龙岩盆地地下水开采潜力评价

本文在阐述龙岩盆地水文地质条件特征的基础上,依据已有的地下水长观资料,在对龙岩盆地地下水资源量进行评价的基础上,认为允许开采量约为26.2万m3/d;并且局部区域还有总量约8万m3/d的开采潜力。     

Visual MODFLOW在地下水数值模拟中的应用——以公主岭市黄龙工业园水源地为例

本文采用定性分析与定量计算相结合、随机模型与确定性模型相耦合的方法,确定了公主岭市黄龙工业园水源地的合理开采量。分析了研究区地下水的补排关系和补给能力;应用VisualMODFLOW 3.1对研究区的地下水流进行了数值模拟,并预报了新水源地投产后地下水水位及流场的时空响应变化;模型预报过程中采用Monte-Carlo随机方法模拟预报了研究区的降水量。模型预报结果表明,在区内和邻区不再增建承压水水源地的情况下,承压水可开采资源量为15800m3/d。为研究区地下水资源的合理开发提供了科学依据。     

长江三峡水库回水对洛碛镇浸没的预测

三峡工程正常蓄水水位175 m时,洛碛镇水位达175.5 m,5年一遇洪水位为176.5 m,20年一遇洪水位为180.7 m,百年一遇洪水位为184.9 m。洛碛镇长江高漫滩地表高程低于183 m,属三峡工程浸没区,库区回水形成的浸没现象普遍。本文通过对洛碛镇地层结构和水文地质条件进行分析,结合历史监测资料,建立回归方程和三维非稳定流地下水流系统,采用常规方法和三维数值模型预测回水后洛碛镇地下水雍高,确定浸没范围及相应程度,为地质环境保护策略提供依据。研究表明,研究区为上下两层地下水位的二元结构,上层水位高于下层水位;库水位保持在175.5 m的时间为41 d,上层地下水从175.5 m壅高的总时间为58 d;数值模拟计算结果能较好的匹配地下水壅高实测值;库水位175.5 m时,浸没区面积为0.386 8 km²。     

Groundwater quality impacts from the land application of treated municipal wastewater in a large karstic spring basin: Chemical and microbiological indicators

Geochemical and microbiological techniques were used to assess water-quality impacts from the land application of treated municipal wastewater in the karstic Wakulla Springs basin in northern Florida. Nitrate-N concentrations have increased from about 0.2 to as high as 1.1 mg/L (milligrams per liter) during the past 30 years in Wakulla Springs, a regional discharge point for groundwater (mean flow about 11.3 m³/s) from the Upper Floridan aquifer (UFA). A major source of nitrate to the UFA is the approximately 64 million L/d (liters per day) of treated municipal wastewater applied at a 774 ha (hectare) sprayfield farming operation. About 260 chemical and microbiological indicators were analyzed in water samples from the sprayfield effluent reservoir, wells upgradient from the sprayfield, and from 21 downgradient wells and springs to assess the movement of contaminants into the UFA. Concentrations of nitrate-N, boron, chloride, were elevated in water samples from the sprayfield effluent reservoir and in monitoring wells at the sprayfield boundary. Mixing of sprayfield effluent water was indicated by a systematic decrease in concentrations of these constituents with distance downgradient from the sprayfield, with about a 10-fold dilution at Wakulla Springs, about 15 km (kilometers) downgradient from the sprayfield. Groundwater with elevated chloride and boron concentrations in wells downgradient from the sprayfield and in Wakulla Springs had similar nitrate isotopic signatures, whereas the nitrate isotopic composition of water from other sites was consistent with inorganic fertilizers or denitrification. The sprayfield operation was highly effective in removing most studied organic wastewater and pharmaceutical compounds and microbial indicators. Carbamazepine (an anti-convulsant drug) was the only pharmaceutical compound detected in groundwater from two sprayfield monitoring wells (1-2 ppt). One other detection of carbamazepine was found in a distant well water sample where enteroviruses also were detected, indicating a likely influence from a nearby septic tank.     

马池口应急水源地开采对区域地下水位影响分析

通过建立地下水系统数值模型,选择地下水模型软件FEFLOW求解,对马池口应急备用水源地启动后,经历两个枯水年,一个平水年后,区域地下水位下降情况进行了预测,水位下降小于3m的面积为174.77km2,下降3～7m的面积为81.86km2,下降7～9m的面积为28.24km2,下降大于9m的面积为15.35km2,预测结果与地下水位监测数据基本吻合。     

Recovery from groundwater extraction in a small catchment area with crystalline bedrock and thin soil cover in Sweden

An experiment has been in progress since 1997 in a small catchment area (28,000 m(2)) with crystalline bedrock and thin soil cover to study the conceivable impact on groundwater conditions of tunneling and the use of groundwater. The impact on hydrology and hydrochemistry from intensive extraction of groundwater at a depth of 50 m in the bedrock has been studied at Lake G?rdsj?n in Sweden. The catchment area was first monitored under pristine conditions, followed by four and a half years of extraction and then a recovery phase. The geological conditions result in a low buffer capacity and high sensitivity to acidification. During the period of extraction, the surface runoff decreased by approximately 50% compared to a nearby reference area. The groundwater extraction caused increased fluctuation in groundwater levels in a wetland, which in turn caused oxidation of reduced sulfur to sulfate. The sulfate concentrations increased almost 100-fold in some instances, causing a lowering of the pH by one unit in shallow groundwater. Since extraction of the groundwater was discontinued, the pH has gradually risen and the sulfate concentrations have decreased. However, the concentration of sulfate in groundwater in the wetland has remained stable at approximately double the pre-experiment levels. Magnesium concentrations were lower after the experiment, caused by exhaustion of the magnesium pool in the wetland through acidification. The extraction of water from the bedrock shortened the retention times and increased the recharge of groundwater in the bedrock. After extraction was terminated, the groundwater levels in the boreholes recovered within a month to levels similar to those before extraction. The hydrochemistry of the bedrock groundwater, which was strongly affected by the hydrochemistry of shallow groundwater during the experiment, has also gradually begun to regain its pre-extraction signature. However, the surface runoff has remained low during the first 2 years of recovery, at about 60% of the volume compared to the unaffected catchment area. This could be explained by delayed recovery in resaturation of the shallow rock that was unsaturated during the experiment.     

Emergency water supply and water resources management in Tongzhou District,Nantong City,China

Water resources emergency management can mitigate regional damage from water emergencies. Taking Tongzhou District, Nantong City as the study area, this paper proposes technical and engineering measures to improve the water emergency management system. This paper chooses groundwater as the alternative emergency water source, and proposes an emergency wells layout scheme according to the disparities between current groundwater supply capacities and the emergency water demands in each planning unit in 2020. Jiuweigang River and Tonglv River are proposed as water-dilution channels to improve the surface water environment and provide suitable water to Tongzhou District by means of sluice gates. Lastly, this paper describes the water resources emergency management mechanism, including the organization system, the response mechanism, and the supporting measures.     

A proposal for the dimensions of protection areas

Although the only way of safeguarding the quality of the groundwater is to prevent any risk of pollution in the whole recharge area, it is mostly impossible to maintain that principle for practical and social reasons. Therefore many different systems for the protection of watersupply-areas are applied, which are based on technical and on socio-economic and administrative factors.From a technical point of view a protection system has to depend on the hydrogeological properties of the aquifer. In this respect an important distinction can be made between porous-permeable (mostly unconsolidated) aquifers and fissured and karstic (consolidated) aquifers, especially in relation to the flow velocity of the groundwater. Moreover, it is appropriate to distinguish between a pollution with persistent compounds and a pollution of a degradable nature, which may lead to a zoning within a protection area.For both types of aquifer a protection zone around the well field is established which should guarantee a delay-time of at least 50–60 days before the groundwater in the aquifer is pumped; that time should be sufficient to break down disease germs.Much larger protection areas are necessary to protect against compounds which are not or hardly degradable; to the question of the size of these areas considerations of safe and continuous water supply are relevant.For porous-permeable aquifers a protection area is proposed which has to guarantee a delay of the groundwater in the aquifer of 25 years; an internal zoning based on a delay of 10 years may be appropriate. As the flow velocity of the groundwater in fissured and karstic rocks is very high, and so the protection areas would be of an enormous extent, this principle may be impractical. In that case the protection area should be restricted to a distance of 2 kilometers from the wells; this distance has been succesfully applied in Germany for a long time.Regulations in the different protection areas can be applied in order to restrict the presence of hardly degradable substances in the zones of 10 and 25 years and of 60 days of delay. In the inner zone of 60 days an additional restriction on the introduction of disease germs is necessary.     

青海巴音格勒河冲洪积扇区水文地质条件分析

青海巴音格勒河山前冲洪积扇中上更新统冲洪积砂砾石含水组层厚度大,岩性颗粒粗,结构松散,渗透性好,补给充足,富水性强。区内水量丰富地段主要分布于巴音格勒河的现代河谷、古河道及冲洪积扇的轴部,为单一大厚度孔隙潜水,据钻孔揭露含水层厚度65.0～101.90 m,含水层岩性主要为中上更新统洪积、冰水堆积的含漂石卵石的砂砾石层,部分含泥质,结构松散。潜水水位埋深80 m左右,单井出水量1900～2410 m³·d-1,水质好,易开采,可作为主要的供水源。区内大厚度潜水含水层主要接受巴音格勒河水的渗漏补给,向冲洪积扇前缘方向径流,进入细土平原带后,由于地形坡降变小,含水介质变细,地下水以泉的形式排泄。     

Impact of geochemical stressors on shallow groundwater quality

Groundwater monitoring wells (about 70 wells) were extensively installed in 28 sites surrounding Lake Texoma, located on the border of Oklahoma and Texas, to assess the impact of geochemical stressors to shallow groundwater quality. The monitoring wells were classified into three groups (residential area, agricultural area, and oil field area) depending on their land uses. During a 2-year period from 1999 to 2001 the monitoring wells were sampled every 3 months on a seasonal basis. Water quality assay consisted of 25 parameters including field parameters, nutrients, major ions, and trace elements. Occurrence and level of inorganics in groundwater samples were related to the land use and temporal change. Groundwater of the agricultural area showed lower levels of ferrous iron and nitrate than the residential area. The summer season data revealed more distinct differences in inorganic profiles of the two land use groundwater samples. There is a possible trend that nitrate concentrations in groundwater increased as the proportions of cultivated area increased. Water-soluble ferrous iron occurred primarily in water samples with a low dissolved oxygen concentration and/or a negative redox potential. The presence of brine waste in shallow groundwater was detected by chloride and conductivity in oil field area. Dissolved trace metals and volatile organic carbons were not in a form of concentration to be stressors. This study showed that the quality of shallow ground water could be related to regional geochemical stressors surrounding the lake.     

Simulation modelling for groundwater safety in an overexploitation situation: the Maggiore Valley context (Piedmont,Italy)

The Maggiore Valley well field plays a fundamental role in supplying drinking water to a large territory of the Piedmont (north-western Italy). However, an increasing demand for water has led to the overexploitation of the groundwater resources. This situation has caused a progressive drawdown of the piezometric level (locally, up to 0.8 m/year), a spatial reduction in the artesian zone, localised land subsidence and damage to wells. The main purpose of this study was the development of a groundwater flow model of the area for analysing the aquifer response to various pumping strategies. Initially, the groundwater flow simulation (achieved by the application of the MODFLOW code) was calibrated satisfactorily. Then, the groundwater response to four scenarios was simulated to explore the best option to mitigate the problem. In three of the scenarios, a withdrawal reduction of 110 l/s was simulated, whilst considering various relocation options for extraction within the well field. The fourth scenario simulated a withdrawal reduction of 150 l/s; this option also assumed a supplementary water supply from the Monferrato Aqueduct, located north of the study area. All the simulations provided an increase in the piezometric level; in some instances, up to 30 m. Based on these simulations, the most promising management strategy for the Maggiore Valley well field would seem to be the option using a supplementary feed from the Monferrato Aqueduct. In this instance, the predicted piezometric level rise would be up to 25 m; this option also precludes the need for drilling additional wells.     

格尔木河冲洪积扇地下水系统及水资源潜力

格尔木河冲洪积扇区有着巨厚的第四系砂卵砾石层,形成了良好的储水空间,研究其含水层系统特征、地下水循环演化及资源开采潜力对水资源合理开发利用具有重要指导意义。本文基于地质调查、水文地质钻探、动态长观等资料,将含水层系统进行了划分,并对地下水的循环演化进行了阐述。运用补给量总和法、排泄量总和法以及断面径流量法对研究区地下水天然资源量和开采潜力进行了计算。结果表明:研究区河水与地下水经历三次转换,主要模式分为:中高山区模式、冲洪积扇区模式、冲湖积平原区模式;含水层系统可分为:局部循环系统、中间循环系统和区域循环系统三个子系统。研究区地下水天然资源量为206.75×10⁴ m³/d,开采潜力达103.38×10⁴ m³/d,可为下游的盐湖产业基地提供水源保障。