北京大兴区浅层地下水水质初步评价

采用模糊数学方法对大兴区82个浅层地下水监测井的水质进行了现状评价。结果表明，中西部水质较好，主要为Ⅱ类和Ⅲ类水，而北部、南部和东部大部分地区水质较差．主要为Ⅳ类和V类水。造成本区地下水水质污染的主要原因是过境污水的渗透、不适当的污水灌溉。     

焦作地区水文地质条件对浅层地下水污染的控制作用研究

通过现场调查、水质分析以及模拟污染物扩散迁移发现,受水文地质条件的控制,在焦作不同区域浅层地下水的主要污染方式不同。水文地质条件还影响着污染物在地下水系统中的分布、迁移。在山前倾斜冲洪积平原地区,主要污染方式为入渗---径流扩散,本区浅层地下水对污染敏感性较高,浅层地下水中污染物浓度高于其他地区,污染物进入地下水系统后在地下径流的控制下自西北向东南方向扩散,沿大沙河一线扩散最快;在山前交接洼地,径流---蒸发浓缩作用成为主要的污染方式,长期的蒸发浓缩作用使得该区总硬度普遍超标;黄沁河冲积平原地区,入渗---蒸发浓缩为主要的污染方式,受包气带土层特殊性质的影响,浅层地下水氟污染较严重。     

干旱绿洲区硝态氮与铵态氮的分布特征及运移特点研究

以焉耆盆地开都河下游灌区为例,通过野外调查、采集水土样品,分析土壤剖面和地下水中氮素含量水平及空间分布特征。结果表明:研究区土壤氮素含量达到一级水平,属于高肥力区;浅层地下水水质在Ⅲ级以下,水质较差,均不满足生活饮用水标准要求。土壤及地下水中氮素含量空间变异属于中等变异,各采样点间氮素含量差异明显,主要受施肥时间和灌水条件影响。土壤剖面硝态氮表层积聚特征明显,存留在根系层的硝态氮含量较高,淋失不显著;铵态氮在土壤剖面主要表现为均匀分布和震荡分布,淋失量较大。该研究结果对预防地下水污染,维护农田生态系统平衡具有重要现实意义。     

焦作地区浅层地下水水质评价

利用焦作地区88个监测孔水质指标检测结果,采用模糊综合评价法对焦作地区浅层地下水中硝酸盐氮、溶解性总固体、硫酸盐、硬度、六价铬、氟化物、镍离子、氨氮、氯化物共9个指标进行评价.通过建立因子集、评价集、隶属度集、模糊权向量矩阵,进行模糊综合运算最终确定研究区浅层地下水水质的级别.评价结果表明,研究区浅层地下水质很差,污染率高达81.82％,其中,劣V类水质高达26.14％,主要分布于北部的大家作、小尚、北敬村以及南部的任庄、小王庄、南李村一带,与工业污染源、农业污染源和生活污染源分布具有一致性.     

沈西工业走廊污染场地浅层地下水无机污染特征

为分析东北平原典型区域浅层地下水污染现状及污染物的化学迁移规律,借助＂东北平原地下水污染调查与评价＂项目收集、野外调查获取的资料,选取布设在沈西工业走廊的一条水文地质剖面所在区域为研究区,绘制地下水流场图与无机污染物浓度等值线图推断污染物的扩散路径,应用相关系数法分析地表水与地下水中无机污染物的相关性,利用PhreeQC地球化学模拟软件计算该剖面的水化学成分的饱和指数,进一步确定无机污染物的运移途径。分析结果表明研究区主要污染源为细河地表水,浑河间接影响其周边地下水水质;地表水和地下水之间水力联系的强弱与人为因素将影响地下水水质;无机污染物以面状污染为主要污染形式,其运移能力受水力梯度与岩相环境中发生的水文地球化学作用的制约。     

保定府河下游两岸浅层地下水水质时间变异特征分析

获取府河下游数字高程图,确定府河及两岸地下水观测点,从2015年5月-2016年4月进行河水及两岸地下水观测,采用描述统计方法对观测结果进行逐月和季节的变异分析,建立了府河和浅层水观测井水质参数与时间关系曲线。结果表明:氨氮、亚硝酸盐和磷酸盐均为强变异性,硝酸盐为中等变异性;认为在非农业生产活动时期的冬春季节府河两岸浅层地下水水质主要受府河水质的影响,且地下水水质变化较府河水质有明显的滞后性;最后把氨氮、硝酸盐、亚硝酸盐作为评价因子使用单因子评价法对府河两岸地下水逐月进行水环境评价,得出除了1、2月份为Ⅳ级外其他月份均属于Ⅴ类水质。     

基于KHA优化BP神经网络的地下水水质综合评价方法

为提高区域地下水水质评价精度,将磷虾群算法(Krill herd algorithm,KHA)引入到BP神经网络连接权值与阈值的优化过程中,构建了KHA-BP地下水水质综合评价模型。以黑龙江省农垦建三江管理局为研究对象,运用所建模型对其下辖15个农场进行地下水水质综合评价,并对造成地下水水质污染的主要原因进行辨识。为验证本文所建模型的适用性,引入区分度法与序号总和理论分别分析了KHA-BP模型、PSO-BP模型以及BP模型的可靠性与稳定性。结果表明:各农场地下水水质良好,且存在一定的空间分布规律,I类水质主要集中在管理局西南位置,Ⅱ类水质主要集中在北部和南部,Ⅲ类水质主要分布于中东部和中西部。Fe、Mn、CODMn、NH_3-N以及NO-3-N是造成地下水水质污染的主要因素。其中Fe、Mn是当地原生危害,CODMn、NH_3-N、NO-3-N含量超标主要与大量施用化肥、农药有关。KHA-BP模型的区分度为1.107 0,Spearman等级相关系数为0.928 6,与PSO-BP模型、BP模型相比优势明显。研究成果可为粮食生产核心区的地下水资源科学管理及水生态文明建设提供科学依据。     

沽源县浅层地下水化学特征及适宜性评价

为查明沽源县浅层地下水水化学特征及水质状况,选取52组样品进行水化学组成分析.运用Piper三线图,确定研究区地下水水化学类型.在此基础上采用了不同的评价方法对该研究区水质现状进行评价.结果表明:该区浅层地下水化学类型主要以HCO₃-Ca型为主;地下水质量综合评价结果显示研究区内18组地下水化学组分是比较高的,适用于农业用水,也可适当处理后作为生活饮用水;16组地下水化学组分高,质量标准评价为Ⅴ类水,不宜作为生活饮用水饮用.为了水资源利用效率,对其进行灌溉用水适宜性评价.通过对16组地下水作为灌溉用水评价,评价结果是DX-39处水质较差,不宜或不太适用于灌溉.研究成果可为该区浅层地下水资源的合理开发和利用提供科学依据,对保证灌溉当地农作物安全有着重要意义.     

基于因子分析的浑河冲洪积扇地浅层地下水水质影响因素辨析

采集浑河冲洪积扇地浅层地下水样品218组,测试了33项水质指标。综合分析结果表明：研究区浅层地下水水质以弱酸性、低矿化、硬水为特征;HCO3.SO4-Ca.Mg、HCO3.SO4-Na.Ca、HCO3.SO4.Cl-Ca、HCO3.SO4-Na.Ca.Mg和HCO3-Ca这5种水化学类型占50%以上。应用SPSS软件,对33项浅层地下水水质指标进行因子分析,定量的筛选出主要影响因素,即基础因子、金属因子、农业因子和类有机因子这4个公因子,且4个公因子都与人类活动密切相关。     

焦作地区浅层地下水中“三氮”污染特征及机制研究

通过研究焦作地区浅层地下水中“三氮”污染量、污染分布特征,分析研究了污染源、水文地质条件对地下水“三氮”的形成、迁移、转化、分布规律的影响。结果表明,硝酸盐氮、氨氮、亚硝酸盐氮的污染分布分别呈现面状、条带状和点状分布;农业上含氮化肥和农药的过量使用是浅层地下水“三氮”污染的主要原因,工业污水直接排入含水层是污染中心浓度极高的重要原因;包气带的碱性氧化环境是硝酸盐氮广泛分布的重要条件,大沙河侧漏补给是氨氮呈现条状分布的主要因素。     

山东省浅埋区地下水环境优化研究

山东省地下水大量超采的同时，也存在着地下水开发利用程度不足，地下水位埋深浅，造成水资源浪费及水环境危害的现象。根据山东省地下水位动态观测资料，划分了地下水浅埋区范围，分析了浅埋区水文地质条件、水利条件，提出了浅埋区地下水环境优化的目标和实施方案，计算分析了浅埋区地下水环境优化效益。     

Simulating root water uptake from a shallow saline groundwater resource

Disposal of saline drainage water is a significant problem for irrigated agriculture. One proposal to deal with this problem is sequential biological concentration (SBC), which is the process of recycling drainage water on increasingly more salt tolerant crops until the volume of drainage water has been reduced sufficiently to enable its final disposal by evaporation in a small area. For maximum effectiveness this concept will require crop water reuse from shallow groundwater. To evaluate the concept of sequential biological concentration, a column lysimeter study was used to determine the potential crop water use from shallow groundwater by alfalfa as a function of ground water quality and depth to ground water. However, lysimeter studies are not practical for characterizing all the possible scenarios for crop water use related to ground water quality and depth. Models are suited to do this type of characterization if they can be validated. To this end, we used the HYDRUS-1D water flow and solute transport simulation model to simulate our experimental results. Considering the precision of the experimental boundary and initial conditions, numerical simulations matched the experimental results very well. The modeling results indicate that it is possible to reduce the dependence on experimental research by extrapolating experimental results obtained in this study to other specific sites where shallow saline groundwater is of concern.     

环鄱阳湖区地下水中氟含量特征及成因分析

于2011年对环鄱阳湖区56口井的水质进行调查研究,应用SPSS和数学统计方法,研究了环鄱阳湖区地下水中氟含量特征及成因分析。结果显示：环鄱阳湖区地下水中氟化物普遍存在,F–离子浓度变化范围为0.001～0.418 mg/L,平均值仅为0.089 mg/L,氟含量普遍偏低,不能满足人们的日常需求,对当地居民的口腔健康存在一定威胁;土壤与岩石性质是影响地下水氟含量偏低的主要因素,另外,地下水的化学成分、气候条件、水体pH值及地下水径流条件等也都在不同程度上影响着地下水中氟的含量与分布。     

基于同位素和水化学的地下水污染机理研究

为查明河南省新乡市浅层地下水的污染机理,通过现场调查并对地下水、地表水进行采样,测定其氢、氧稳定同位素及水化学成分,对水样的氢氧同位素和水化学组成的空间分布规律进行了分析。结果表明:降水是地下水的主要补给源。太行山区是剥蚀丘陵岗地地下水的主要补给区;中部冲洪积平原地下水受共产主义渠水的影响,二者同位素值较接近;受黄河灌溉回归水的影响,南部冲积平原地下水氢氧同位素值较接近黄河水,是大气降水和黄河水的混合水体。而研究区地下水污染除与地表污水侧渗、污染物通过包气带直接下渗有关,还与不合理开采地下水导致盐分和污染物的迁移有关。     

Sustainability of conjunctive water use for salinity control in irrigation areas: theory and application to the Shepparton region,Australia

The long term sustainability of conjunctive water use for controlling irrigation salinity is affected by increase in groundwater salinity over time. This paper uses mass conservation of salt and water to assess groundwater degradation over long time scales. Management options which affect this rate of degradation are also examined. The groundwater model developed is illustrated using data from the Shepparton Irrigation Region in the Murray Basin, Australia. The model predicts rapid groundwater deterioration when conjunctive use is conducted over only a fraction of the area of influence of a groundwater pump. Where the pumped aquifer is underlain by deeper groundwaters, the rate of groundwater degradation is also affected by leakage into or out of the conjunctive use system. Surface redistribution of groundwater from pumps installed in zones of regional groundwater discharge to areas recharging the regional groundwaters, reduces excessive degradation in the zones of discharge. With optimal surface distribution of groundwater, the rate of degradation is low. The rate of groundwater degradation also depends on salt inputs from irrigation water and rainfall, and the average depth from the soil surface to the base of the aquifer. The rate of degradation resulting from applied salts in surface water and rainfall is typically about 0.01 dSm^-1 per year for shallow aquifers in the Shepparton region, but the rate is lower where deeper aquifers are pumped. Partial irrigation also reduces the rate of degradation because of the reduced rate of salt inputs. Where poorer quality groundwater lies within the area of influence of the groundwater pump, a greater rate of deterioration in the quality of pumped groundwater can be expected from groundwater mixing. In some irrigation regions limited export of groundwater through surface water conveyance structures to a river is possible, so that a regional surface salt balance could be maintained. However, salt exports made equal to the rate of surface imports into the irrigated area will only significantly impact groundwater salinity in the very long term, or where only shallow aquifers can be pumped. In addition, this export can be costly for downstream water users, or if construction of additional conveyance infrastructure is extensive; export can have a detrimental impact on riverine ecosystems. Other management options such as the depth of pump installation and the spatial distribution of irrigation water and pumped groundwater, which affect the redistribution of salts within the groundwater system, have the potential to have a much greater impact on local groundwater salinity.     

In situ use of groundwater by alfalfa

Disposal of saline drainage water is a significant problem for irrigated agriculture. One proposal is to recycle drainage water to irrigate salt tolerant crops until the volume has been reduced sufficiently to enable final disposal by evaporation. Part of this concept requires in situ crop water reuse from shallow groundwater; and data is needed to quantify the potential use of groundwater by alternative crops. A column lysimeter study was initiated to determine the potential crop water use from shallow groundwater by alfalfa as a function of groundwater quality and depth to groundwater. The results demonstrated that up to 50% of the crop water use could be met from shallow groundwater (<1.2 m) with an electrical conductivity less than 4 dS/m, and that the potential crop water use from deeper groundwater (2 m) increased over the years. The columns with high salinity (>4 dS/m) in the shallow groundwater experienced increased salinity in the soil profile with time, which resulted in reduced crop water use from shallow groundwater. Yields decreased with time as the groundwater salinity increased and periodic leaching will be required for in situ use to be a sustainable practice. Statistical analysis of crop yield demonstrated that there was significant use of groundwater with an EC of 6 dS/m for a few years.