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21.
峰局五矿是多年开采的老矿。近些年,随着开采深度的不断增加和开采层次的逐渐下移,来自底部岩溶高承压水的威胁日趋严重,实际生产能力逐年下降。下组煤能否开采是关系到矿井生存与发展的大问题。作者根据多年的研究成果和工作实践,就下组煤带压开采的可行性,谈一些看法和建议。  相似文献   
22.
Understanding spatio-temporal suspended sediment dynamics is more important in large watersheds due to the decisive role of local source apportionment in sediment transport and yield. The Talar River with a large mountainous watershed in northern Iran, which plays a vital role in water supply for agriculture and drinking, recently has faced quality degradation. The current study explores the relative contribution of suspended sediment sources using geochemical tracers and fingerprinting techniqu...  相似文献   
23.
There continues to be reluctance in some jurisdictions to use chemical dispersants as a viable countermeasure for accidental oil spills. One argument used by some opponents to dispersant use is that “chemical dispersants do not work effectively in cold water”. To address this issue, the U.S. Minerals Management Service (MMS) funded and conducted two series of large-scale dispersant experiments in very cold water at Ohmsett - The National Oil Spill Response Test Facility, located in Leonardo, New Jersey in February-March 2006 and January-March 2007. Alaska North Slope, Endicott, Northstar and Pt. McIntyre crude oils and Corexit 9500 and Corexit 9527 dispersants were used in the two test series. The crude oils were tested both when fresh and after weathering. Results demonstrated that both Corexit 9500 and Corexit 9527 dispersants were 85-99% effective in dispersing the fresh and weathered crude oils tested at cold temperatures. The MMS expects that results from these test series will assist government regulators and responders in making science based decisions on the use of dispersants as a response tool for oil spills in the Arctic.  相似文献   
24.
Drinking water supplies in Ulaanbaatar, the capital of Mongolia, are completely dependent on groundwater sourced from pumping wells located in an alluvial plain of the Tuul River which flows through Ulaanbaatar. The interaction between groundwater in the alluvial plain and river surface water was investigated using a hydrological and multi-tracers approach. The observed groundwater contour map clearly shows that the Tuul River recharges the floodplain groundwater and groundwater flows from east to west. The similarity of chemical and stable isotopic compositions suggests that groundwater is mainly recharged by Tuul River water in the vicinity of the river. In addition, considering groundwater contours and chemical composition, groundwater in the northern and southern mountain sides contribute to floodplain groundwater. Stable isotopic information suggests that winter season precipitation also contributes to the groundwater, because groundwater in a specific region has a considerably lower isotopic ratio. Using the End Member Mixing Analysis applying oxygen-18, SiO2 and HCO3 - as tracers, the contribution ratios of the Tuul River, groundwater in the northern and southern mountain regions, and winter season precipitation to floodplain groundwater are estimated to be 58% to 85%, 1% to 54%, 0% to 16%, and 0% to 12%, respectively.  相似文献   
25.
The RUNOFF block of EPA's storm water management model (SWMM) was used to simulate the quantity and quality of urban storm water runoff from four relatively small sites (i.e. 5·97–23·56 ha) in South Florida, each with a specific predominant land use (i.e. low density residential, high density residential, highway and commercial). The objectives of the study were to test the applicability of this model in small subtropical urban catchments and provide modellers with a way to select appropriate input parameters to be used in planning studies. A total of 58 storm events, measured by the US Geological Survey (USGS), provided hyetographs, hydrographs and pollutant loadings for biological oxygen demand (BOD5), total suspended solids (TSS), total Kjeldahl nitrogen (TKN) and lead (Pb), and were used for calibration of the model. Several other catchment characteristics, also measured or estimated by USGS, were used in model input preparation. Application of the model was done using the Green–Ampt equation for infiltration loss computation, a pollutant accumulation equation using a power build-up equation dependent on the number of dry days, and a power wash-off equation dependent on the predicted runoff rate. Calibrated quantity input parameters are presented and compared with suggested values in the literature. The impervious depression storage was generally found to be the most sensitive calibration parameter, followed by the Manning's roughness coefficients of conduit and overland flow, the Green–Ampt infiltration parameters and, finally, the pervious depression storage. Calibrated quality input parameters are presented in the form of regression equations, as a function of rainfall depth and the number of antecedent dry days. A total of 16 independent rainfall events were used for verification of the model, which showed a good comparison with observed data for both hydrographs and pollutant loadings. Average model predictions for the four constituent concentrations from the verification runs also showed good agreement with NURP published values in Florida and US sites. © 1998 John Wiley & Sons, Ltd.  相似文献   
26.
基于Matlab的断裂带温泉水地球化学特征及地震活动性研究   总被引:1,自引:0,他引:1  
基于Matlab开发出地下流体分析软件,对比分析了甘肃西秦岭北缘的武山、街子和清水温泉水化学组分特征;初步分析了温泉水水质类型、补给来源、水-岩平衡状态以及循环深度,并讨论了温泉水深循环对地震活动性的影响.研究表明温泉水均为大气降水成因,其水化特征受围岩的控制作用;清水温泉水的成熟度没有武山和街子温泉水高.地下水循环深度较浅的武山温泉和街子温泉水化类型属于Na-HCO3·SO4·Cl,所处断裂的地震活动频繁;地下水循环深度较深的清水温泉水化类型属于Na-SO4·Cl,所处断裂的地震活动性弱.  相似文献   
27.
This article provides a historical account of Chinese public policy on fisheries subsidies, and a discussion of problems and limitations resulting from the World Trade Organization (WTO) Doha Round fisheries subsidies negotiation. By analyzing subsidization trends and applying a proportional assessment of subsidized areas, the article tracks the evolvement of Chinese fishery policy objective and priorities. Chinese fishery is not historically significantly subsidized in light of its relatively market-oriented structure and a sustained momentum in reducing marine capture capacity. However, due to the commitment to encouraging qualitative growth and to satisfying a rising domestic demand for fish, the government seeks for adequate policy space to employ fuel, distant water fisheries, infrastructure and various ‘green light’ subsidies. Whether or not such a claim can be accepted as a developmental right not an exception remains to be answered by the revision of current negotiation draft.  相似文献   
28.
A resistance model to calculate the deposition of cloud droplets on a coniferous forest and some improved parameterizations of the indispensable input parameters are described. The deposition model is adapted to the coniferous forest at the Kleiner Feldberg site and verified by the data of a drip water monitoring station below the forest canopy. The measurements of liqud water content, wind speed and trace substance compounds in cloud water of the Ground-based Cloud Experiment (GCE) at Kleiner Feldberg in 1990 are used to calculate the cloud water deposition fluxes and the deposition of trace substances via cloud water interception. The calculated deposition of trace substances via cloud water interceptions is three to six times higher than via rain during the experiment. On a long term data basis the yearly amount of cloud water deposition is 180 mm year–1 at Kleiner Feldberg site (840 m a.s.l.) while the precipitation amount is 1030 mm year–1. Due to higher trace substance concentrations in cloud water compared to rain the ionic deposition via cloud water interception and via precipitation were assessed to be of comparable magnitude.  相似文献   
29.
30.
张文强  滕跃  唐飞  王金晓  许庆宇  张海林 《中国岩溶》2023,42(5):1047-1060, 1084
地下水是肥城地区最主要的供水水源,近年来受到工农业生产、煤矿开采、闭坑、矿井排水等人类活动影响,肥城地区地下水动力场及化学场都发生了变化,为查明地下水的环境质量状况,文章在研究水文地质调查和样品采集分析基础上,综合运用数理统计方法、水化学方法(Piper三线图、Gibbs模型、矿物饱和指数、离子比例分析)等,探讨肥城断块地下水水化学特征及演化规律。结果表明:(1)研究区地下水均呈弱碱性,$ {\mathrm{C}\mathrm{a}}^{2+} $、$ {\mathrm{M}\mathrm{g}}^{2+} $、$ {{\mathrm{H}\mathrm{C}\mathrm{O}}_{3}}^{-} $和$ {\mathrm{S}\mathrm{O}}_{4}^{2-} $为主要离子,主要来源于方解石、白云石及石膏溶解;矿物饱和指数表明方解石和白云石绝大多数处于饱和状态,石膏和岩盐矿物呈溶解未饱和状态。(2)区内岩溶水化学类型主要为$ {\mathrm{H}\mathrm{C}\mathrm{O}}_{3}-\mathrm{C}\mathrm{a}\left(\mathrm{M}\mathrm{g}\right) $型,其次为$ {\mathrm{H}\mathrm{C}\mathrm{O}}_{3}·{\mathrm{S}\mathrm{O}}_{4}-\mathrm{C}\mathrm{a} $型和$ {\mathrm{H}\mathrm{C}\mathrm{O}}_{3}·\mathrm{C}\mathrm{l}-\mathrm{C}\mathrm{a} $型。孔隙水主要为$ {\mathrm{S}\mathrm{O}}_{4}·{\mathrm{H}\mathrm{C}\mathrm{O}}_{3}-\mathrm{C}\mathrm{a} $型、局部出现$ {\mathrm{S}\mathrm{O}}_{4}{·\mathrm{N}\mathrm{O}}_{3}-\mathrm{C}\mathrm{a} $型。河流水化学类型相对复杂,包括$ {\mathrm{S}\mathrm{O}}_{4}·{\mathrm{H}\mathrm{C}\mathrm{O}}_{3}-\mathrm{C}\mathrm{a}·\mathrm{N}\mathrm{a} $型、$ \mathrm{C}\mathrm{l}·{\mathrm{S}\mathrm{O}}_{4}-\mathrm{C}\mathrm{a}·\mathrm{N}\mathrm{a} $型等。(3)区内地下水中$ {\mathrm{C}\mathrm{l}}^{-} $、$ {\mathrm{S}\mathrm{O}}_{4}^{2-} $和$ {\mathrm{N}\mathrm{O}}_{3}^{-} $含量相比1999年、2013年显著升高。裂隙水及岩溶水水质整体较好,局部呈点状变差,孔隙水及河水水质普遍较差,影响区域地下水水质的主要因素有化肥施用、禽畜养殖、生活污水下渗以及煤矿排水等。  相似文献   
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