模拟优化模型在地下水监测布井中的应用

以北京市某农田用地地下水监测井为研究对象,基于农田水文地质参数建立了地下水多目标模拟优化模型。结合Monte Carlo分析法分析了地下水水流模型和溶质运移模型参数的不确定性,并求解了单口监测井的影响半径,最后借助NSGA-Ⅱ算法建立了两个目标函数之间的权衡关系。模型求解结果表明,监测系统可靠性目标最大为76.8%,对应的监测井数量最小为3口;当扩大污染羽的控制边界时,可以建立4口监测井。研究结果表明,模拟优化模型可以用于地下水监测井布井优化当中,建立两个目标函数之间合理的权衡关系,确定监测井的数量和位置,保证监测系统的可靠性。     

水质模型参数识别的遗传算法

Ｏ’ｃｏｎｎｏｒ模型是一个比广泛应用的Ｓｔｒｅｅｔｅｒ－Ｐｈｉｌｉｐｓ模型更精确的水质模型,由于该模型参数率定的困难性,限制它在实际中应用。     

基于模糊权物元理论的地下水水质评价模型构建及应用

在物元分析的基础上,结合模糊权重理论与层次分析方法,构建用于评价地下水水质的模糊权物元分析模型。应用此模型对徐州市的重要水源地——张集水源地的地下水水质进行了综合评价。选取数据较为完整的20个监测井的监测数据进行评价。结果表明,研究区的20个采样点水质为Ⅱ、Ⅲ级的占95%,绝大多数地下水水质较好,符合饮用水的要求。与投影寻踪法和模糊概率法的评价结果比较发现,得出的评价结果与以上2种评价结果基本一致。     

污灌区与非污灌区的地下水主要水质指标变化趋势及对比研究

通过对水文地质条件和天然条件下水质相似的一处非污水灌溉地区水与一处污水灌溉区地下水水质的对比研究，得出污水灌溉区地下水水质为差主要是由化肥和污水灌溉共同引起的，且非污灌区地下水质要好于污灌区的水质。污水灌溉对地下水的影响程度与化肥对地下水的基本相同。同时本文也独立地给出了污水灌溉和化肥对地下水质的影响规律。     

基于时序蒙特卡罗方法的某铬盐场污染地下水泄漏风险

突发性污染地下水泄漏对周围水环境的影响具有重要研究意义。借鉴时序蒙特卡罗(SMC)方法来模拟污染源运行状态,并结合相应的河流水质模型,对污染地下水泄漏后造成的河流水质超标风险概率进行研究;利用健康风险评价模型,对污染物泄漏时水环境造成的人体健康风险进行评价。以某铬盐场为例验证该方法的稳定性和实用性。结果表明,该场地受污染的地下水对人体健康产生的危害程度为中级,其超标风险概率随模拟时间的增加而趋于稳定。     

基于灰色模型和模糊神经网络的综合水质预测模型研究

水质状态变化趋势预测研究对水资源管理和维护具有重要的现实意义。提出了一种将灰色模型和模糊神经网络相结合的水质预测模型。首先基于改进的灰色模型预测出水体中各理化因子在未来一段时间内的指标变化,然后采用T-S模糊神经网络对各单因子的预测值进行数据融合,构建水质变化综合趋势预测模型,预测出下一时间段的水质整体状态指标。实验表明,这种方式用来预测湖泊水质变化趋势具有可行性;与BP网络模型相比,基于T-S模糊神经网络系统的模型具有预测精度高、模型系统稳定等优越性。     

基于支持向量机的地下水质量综合评价

提出基于支持向量机（SVM）机器学习算法的地下水质量评价模型。首先给出了训练样本生成和数据规范化处理的具体方法,然后采用支持向量机的多分类算法构建模型,并使用k折交叉核实方法对参数进行验证优化。最后通过实证分析,并与单因子指数法、模糊综合评价法和BP神经网络法的评价结果对比分析可知,该方法简便易行,评价结果客观且准确度较高,具有很强的实用性。     

杭州市区地下水质量评价

采用综合评分法对杭州市区及近郊各类型地下水１９９７年的水质监测结果进行科学评价,为有关部门科学管理和合理开发利用地下水资源提供决策依据。     

基于人工蜂群算法与BP神经网络的水质评价模型

针对BP网络水质评价模型的不足,引入人工蜂群(ABC)算法,将求解BP神经网络各层权值、阀值的过程转化为蜜蜂寻找最佳蜜源的过程,提出了一种新的结合人工蜂群算法的BP网络水质评价方法(ABC-BP)。并以2000—2006年渭河监测断面的10组实测数据作为测试样本对其水质进行了评价,实验结果表明该方法得到的水质评价结果准确,并具有很强的稳定性和鲁棒性。     

Direct measurements of the tile drain and groundwater flow route contributions to surface water contamination: From field-scale concentration patterns in groundwater to catchment-scale surface water quality

Enhanced knowledge of water and solute pathways in catchments would improve the understanding of dynamics in water quality and would support the selection of appropriate water pollution mitigation options. For this study, we physically separated tile drain effluent and groundwater discharge from an agricultural field before it entered a 43.5-m ditch transect. Through continuous discharge measurements and weekly water quality sampling, we directly quantified the flow route contributions to surface water discharge and solute loading. Our multi-scale experimental approach allowed us to relate these measurements to field-scale NO₃ concentration patterns in shallow groundwater and to continuous NO₃ records at the catchment outlet. Our results show that the tile drains contributed 90-92% of the annual NO₃ and heavy metal loads. Considering their crucial role in water and solute transport, enhanced monitoring and modeling of tile drainage are important for adequate water quality management.     

黄河入海口水质评价与预测

对黄河入海口2004-2011年的水质进行评价与预测,采用灰色聚类法分析水体DO、CODMn、NH3-N 3项指标,总结水质年均变化情况.建立水质GM(1,1)灰色预测模型,用实际水质指标值检验其精度,并用此模型预测未来4年水质变化趋势.结果表明,2004-2015年期间,黄河入海口水质在2004-2007年波动较大,但将越来越好,CODMn、NH3-N呈下降趋势,DO、达标率呈上升趋势,并通过灰色关联分析方法分析水质变化原因以期对黄河入海口水质分析预测与水体保护工作提供参考.     

A detailed field-based evaluation of naphthenic acid mobility in groundwater

An anaerobic plume of process-affected groundwater was characterized in a shallow sand aquifer adjacent to an oil sands tailings impoundment. Based on biological oxygen demand measurements, the reductive capacity of the plume is considered minimal. Major dissolved components associated with the plume include HCO₃, Na, Cl, SO₄, and naphthenic acids (NAs). Quantitative and qualitative NA analyses were performed on groundwater samples to investigate NA fate and transport in the subsurface. Despite subsurface residence times exceeding 20 years, significant attenuation of NAs by biodegradation was not observed based on screening techniques developed at the time of the investigation. Relative to conservative tracers (i.e., Cl), overall NA attenuation in the subsurface is limited, which is consistent with batch sorption and microcosm studies performed by other authors. Insignificant biological oxygen demand and low concentrations of dissolved As (< 10 µg L^− 1) in the plume suggest that the potential for secondary trace metal release, specifically As, via reductive dissolution reactions driven by ingress of process-affected water is minimal. It is also possible that readily leachable As is not present in significant quantities within the sediments of the study area. Thus, for similar plumes of process-affected groundwater in shallow sand aquifers which may occur as oil sands mining expands, a reasonable expectation is for NA persistence, but minimal trace metal mobilization.     

水质评价中模糊-集对分析法的改进

针对水环境的不确定性和模糊性,基于集对分析法和模糊理论相结合的评价模型已被广泛运用到水质评价当中。传统的评价模型在确定水质等级的复合算法中虽引入了权值的概念,但仍会出现指标浓度重复计算、信息丢失和指标权值的影响得不到体现等缺陷,具有局限性。针对这些缺陷,将基于加权后的内梅罗指数法思想应用于传统模糊-集对分析法中的复合算法上,考虑到加权内梅罗指数法兼顾极值的特性及计权性,通过取平均值和极值替代累加的方法来实现减小指标浓度重复计算的影响,同时加强复合算法中权值所占比重使得权值的作用得到充分体现。实验表明,改进的复合算法使得评价结果更为精确、客观。     

WebGIS与一维水质模型的集成研究

结合江苏省环保信息系统的建设，讨论WebGIS与一维水质模型集成的关键技术问题，阐明模型计算中评价河段截取、空间离散及空间数据重采样的方法和过程，对实现水环境模型的跨平台操作和数据信息共享作出了尝试，设计了基于浏览器方式的集成系统。     

Hydrochemistry of urban groundwater, Seoul, Korea: the impact of subway tunnels on groundwater quality

Hydrogeologic and hydrochemical data for subway tunnel seepage waters in Seoul (Republic of Korea) were examined to understand the effect of underground tunnels on the degradation of urban groundwater. A very large quantity of groundwater (up to 63 million m³ year^− 1) is discharged into subway tunnels with a total length of 287 km, resulting in a significant drop of the local groundwater table and the abandonment of groundwater wells. For the tunnel seepage water samples (n = 72) collected from 43 subway stations, at least one parameter among pathogenic microbes (total coliform, heterotrophic bacteria), dissolved Mn and Fe, NH₄⁺, NO₃⁻, turbidity, and color exceeded the Korean Drinking Water Standards. Locally, tunnel seepage water was enriched in dissolved Mn (avg. 0.70 mg L^− 1, max. 5.58 mg L^− 1), in addition to dissolved Fe, NH₄⁺, and pathogenic microbes, likely due to significant inflow of sewage water from broken or leaking sewer pipes.Geochemical modeling of redox reactions was conducted to simulate the characteristic hydrochemistry of subway tunnel seepage. The results show that variations in the reducing conditions occur in urban groundwater, dependent upon the amount of organic matter-rich municipal sewage contaminating the aquifer. The organic matter facilitates the reduction and dissolution of Mn- and Fe-bearing solids in aquifers and/or tunnel construction materials, resulting in the successive increase of dissolved Mn and Fe. The present study clearly demonstrates that locally significant deterioration of urban groundwater is caused by a series of interlinked hydrogeologic and hydrochemical changes induced by underground tunnels.