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污灌区浅层地下水污染风险评价研究 总被引:10,自引:0,他引:10
以污灌区土壤作为风险源,以地下水系统作为风险受体,建立了包含地下水脆弱性、地下水特征污染物容量指数及土壤特征污染物潜在生态危害指数的地下水污染风险评价概念模型。以太原市小店污灌区为例,利用该模型对浅层地下水污染风险进行评价。结果表明:污灌区地下水脆弱性相对较低,特征污染物分布较为集中;受含水层脆弱性指数、特征污染物容量指数及潜在生态危害指数的影响,污灌区浅层地下水污染风险高低分布不均,较高污染风险区和高风险区分布在西吴、贾家寨、梁家庄等村庄以及汾河、萧河沿岸一带,占区域面积的31%。研究成果可为污灌区地下水污染风险分区提供参考依据。 相似文献
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岩溶地下水资源是西南地区社会和经济发展的重要保障,随着城市化进程的不断加快,西南地区岩溶地下水污染问题也日益凸显,直接威胁当地群众的健康安全,已成为社会热点。以西南地区典型岩溶地下水系统污染实例为研究对象,通过分析每个岩溶地下水系统污染实例的水文地质条件、污染源特征、污染物迁移规律及污染危害等方面,归纳总结西南地区典型岩溶地下水系统污染模式,分为四种:间歇型入渗污染、持续型入渗污染、灌入型污染和越流型入渗污染。该项研究便于识别污染物的运移特征及规律、掌握污染范围和污染程度,为西南岩溶地区地下水污染物的防治工作提供重要的借鉴意义。 相似文献
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地下水污染相比于地表水与大气污染,具有隐蔽性、滞后性和不可逆性等特点,污染物进入地下水后,随着水流不断扩散,难以及时找到污染源头并进行有效控制。对于地下水中的污染进行溯源,是进行土壤地下水污染修复的前提条件。同时,水污染事件中污染物来源不清也会导致责任归属难判定,从而引起案件纠纷等系列问题。首先对常见的地下水污染物的种类和来源进行了归纳,之后对目前地下水污染溯源技术和主要研究方向进行了综述,最后结合溯源方法的实践应用提出该方向应用的重难点。 相似文献
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针对日益严重的高尔夫球场地下水污染问题,以高尔夫球场的地下水污染防渗和保障城市供水安全为目标,为了预测高尔夫球场的地下水污染风险和探究其防渗方法,以北方某高尔夫球场为例,通过分析研究区概况,基于FEFLOW建立了地下水流和溶质运移模型,采用数值分析方法,预测球场污水处理设施失效时的地下水污染风险,并评估防渗效果。结果表明:在污水处理设施失效100 d时,锰扩散最远距离为112. 45 m,六六六扩散最远距离为48. 50 m,短期内扩散较快,对下游居民区产生威胁;防渗措施应用后100 d时,污染物扩散最远距离约为50. 2 m;应用1 000 d时,污染物扩散最远距离约为54. 8 m,扩散范围变化不大且控制在球场范围内,防渗效果良好。该数值分析方法很好的预测了污染物在有无防渗两种工况下的迁移情况,通过设置防渗层和防渗帷幕有效阻滞了污染物迁移,研究成果对高尔夫球场的地下水污染控制具有一定的借鉴意义。 相似文献
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This paper investigates the effectiveness of geostatistical approaches, specifically ordinary kriging, for regional management
of arsenic contaminated shallow ground water in Bangladesh. The arsenic database for reference comprised the nation-wide survey
(of 3534 drinking wells) completed in 1999 by the British Geological Survey (BGS) in collaboration with the Department of
Public Health Engineering (DPHE) of Bangladesh. A Monte Carlo (MC) framework was devised for selection of randomly-sampled
networks of wells from this reference database. Each randomly sampled network was assumed an equi-probable exploratory field
campaign designed commensurably with the requirements of rapidity and cost-effectiveness in a rural setting. In general, the
kriging method was found to underestimate the arsenic concentration at non-sampled locations. This underestimation exceeded
the safe limits at the Holocene region of Southcentral Bangladesh. The probability of successful prediction of safe wells
for this region was found to be 72% (WHO safe limit – 10 ppb) and 78% (Bangladesh safe limit – 50 ppb). For the Pleistocene
Northwestern region of Bangladesh, the safe well prediction probability was in the ranges of 90%–97%. The relatively more
contaminated Holocene region in Southcentral Bangladesh, on other hand, was found more amenable to accurate geostatistical
prediction of unsafe wells. Findings from this study exemplify that, while mainstream geostatistical approaches (e.g., ordinary
kriging) may not provide the most accurate prediction of mean arsenic concentration at non-sampled locations, they can delineate
an approximate strategy for management of arsenic contaminated shallow ground water if applied carefully. The kriging methodology
is applied to a test case in Bangladesh; the approach, however, is general and is expected to have application in rural settings
for other developing countries where arsenic contamination of ground water is also widespread (e.g., parts of India, Vietnam,
Taiwan and Mexico). 相似文献
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探针杆挠曲对水流场测量的影响研究 总被引:4,自引:0,他引:4
绕流阻力引起探针杆弹性挠曲,针头挠度和转角造成测点位置误差和流速方向或分量测量误差。本文提出根据探针测定的原始速度分布求解针头在各测点处的转角,进而确定实际流速方向、流速分量和测点位置误差。方法成功地用于探针测定的三维流场的误差计算和修正。结果表明,沿杆长方向的流速误差最大,不能忽视。最后,给出误差修正计算实用近似方法。 相似文献
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The effect of the bottom slope on abrupt deflected supercritical water flow was experimentally and theoretically studied. Model tests were conducted in a flume of 1.2 m wide and 2.6 m long with sloped bottom at an angle 35.54°, its length of deflector was 0.2 m and the deflection angles were 15° and 30°. An approximate method for calculating the shock wave angle and depth ratio of the abrupt deflected supercritical water flow was suggested, and a correction coefficient for the hydrodynamic pressure was introduced to generalize the momentum equation in the direction perpendicular to the shock front. It must be noticed that in the sloped channel the shock wave angle and the depth ratio are no longer constant as those in the horizontal channels, but slowly change along the shock front. The calculated results are in good agreement with measured data. 相似文献
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采用Monte Carlo模拟分析技术,研究了多项式正态变换(PNT)法的稳健性能,并与线性矩(L M)法进行了比较.结果表明:在污染样本情况下,PNT法无偏性优于L M效性略差于L M法;当污染样本比例较大时,与L M法相比,PNT法更具稳健性.因此,当样本组成复杂或总体分布难以确定时,采用PNT法估计水文变量的设计值,有望提高估计精度. 相似文献
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In this study, porosity was introduced into two-dimensional shallow water equations to reflect the effects of obstructions, leading to the modification of the expressions for the flux and source terms. An extra porosity source term appears in the momentum equation. The numerical model of the shallow water equations with porosity is presented with the finite volume method on unstructured grids and the modified Roe-type approximate Riemann solver. The source terms of the bed slope and porosity are both decomposed in the characteristic direction so that the numerical scheme can exactly satisfy the conservative property. The present model was tested with a dam break with discontinuous porosity and a flash flood in the Toce River Valley. The results show that the model can simulate the influence of obstructions, and the numerical scheme can maintain the flux balance at the interface with high efficiency and resolution. 相似文献
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滑坡从孕灾到成灾的演化过程与其所处的地质环境密切相关,其中对地形因子具有较高的敏感性。基于GIS和RS研究技术,以清江流域宣恩县为研究对象,选取坡度、坡向、地形起伏度和平面曲率等4个地形要素作为敏感性分析评价因子,分别采用敏感性系数法和条件概率法进行敏感性分析对比研究。研究结果表明:两种分析方法所获得的敏感性分区面积基本接近,且与地表地质调查的滑坡信息基本相同。可为类似宣恩县这种中小区域滑坡灾害评价和预测提供新的思路和参考,且对中小区域防灾和规划具有一定的宏观决策意义。 相似文献
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Ha I Chung 《Water science and technology》2007,55(1-2):329-338
A series of laboratory experiments involving simple, ultrasonic, electrokinetic, electrokinetic/ ultrasonic flushing test were carried out for treatment and removal of heavy metal and hydrocarbon from contaminated groundwater in sandy layers under a river bank. The test results show that the electrokinetic/ultrasonic flushing technique is most effective for the removal of heavy metal and hydrocarbon from contaminated sandy layers by the coupling action of their own phenomena. It is shown that the electrokinetic technique is most effective to enhance the removal efficiency of heavy metal contaminants such as cadmium from contaminated sandy soil under the river bank; on the other hand the ultrasonic technique is most effective to enhance the removal efficiency of hydrocarbon contaminant, such as diesel fuel from contaminated soil. 相似文献