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41.
本文据珠江口周年(1987年2月至1988年2月)调查资料,分析了珠江口桂山岛附近海域的三氮变化规律,讨论了三氮之间的相互关系,通量和停留时间以及各种因素对三氮的影响。结果表明:珠江河口水中三氮的时空分布具有夏、冬季含量高,春、秋季含量低,并随向外海方向递减的特点;三氮之间的关系可分别用倒指数方程Y=exp(A+B/X)的数学模式描述;NH_4-N,NO_3-N,NO_2-N的通量和停留时间分别为33.9,401.0,15.8g·atN/s和3.84,3.96,4.41d。 相似文献
42.
西太平洋暖池区气象学特征分析 总被引:1,自引:0,他引:1
本文根据TOGA-COARE强化观测资料及卫星资料分析讨论了西太平洋暖池区11-2月间海面气象要素的平均特征。分析发现海面气压平均日变化似乎同中纬度区明显不同。文中还分析讨论了在西太暖池区西风爆发、赤道浅涡、信风逆温及ITCE和南太平洋辐合带SPCZ的变化特征。 相似文献
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Mark A. Engle Fraser Goff David G. Jewett Gregory J. Reller Joel B. Bauman 《Hydrogeology Journal》2008,16(3):559-573
Boron, chloride, sulfate, δD, δ18O, and 3H concentrations in surface water and groundwater samples from the Sulphur Bank Mercury Mine (SBMM), California, USA were
used to examine geochemical processes and provide constraints on evaporation and groundwater flow. SBMM is an abandoned sulfur
and mercury mine with an underlying hydrothermal system, adjacent to Clear Lake, California. Results for non-3H tracers (i.e., boron, chloride, sulfate, δD, and δ18O) identify contributions from six water types at SBMM. Processes including evaporation, mixing, hydrothermal water input
and possible isotopic exchange with hydrothermal gases are also discerned. Tritium data indicate that hydrothermal waters
and other deep groundwaters are likely pre-bomb (before ~1952) in age while most other waters were recharged after ~1990.
A boron-based steady-state reservoir model of the Herman Impoundment pit lake indicates that 71–79% of its input is from meteoric
water with the remainder from hydrothermal contributions. Results for groundwater samples from six shallow wells over a 6–month
period for δD and δ18O suggests that water from Herman Impoundment is diluted another 3% to more than 40% by infiltrating meteoric water, as it
leaves the site. Results for this investigation show that environmental tracers are an effective tool to understand the SBMM
hydrogeologic regime.
Electronic supplementary material The online version of this article (doi:) contains supplementary material, which is available to authorized users.
Electronic supplementary material The online version of this article (doi:) contains supplementary material, which is available to authorized users.
Résumé Les concentrations en bore, chlorure, sulfate, δD, δ18O, et 3H d’échantillons d’eaux de surface et souterraine prélevés dans le banc de soufre de la mine de mercure (SBMM en anglais) en Californie, USA, ont été utilisées pour étudier les processus géochimiques et pour fournir des contraintes à l’évaporation et à l’écoulement des eaux souterraines. La SBMM est une mine de soufre et de mercure abandonnée, adjacente au lac Clear en Californie et sous laquelle se trouve un système hydrothermal.Les résultats des traceurs autres que le tritium (bore, chlorure, sulfate, δD, et δ18O) ont permis d’identifier des contributions de six types d’eaux à SBMM. Des processus tels que l’évaporation, le mélange, l’entrée d’eau hydrothermale et de possibles échanges isotopiques avec des gaz hydrothermaux ont également été identifiés. Les données de tritium montrent que les eaux hydrothermales et d’autres eaux profondes sont probablement d’age antérieure à la bombe (avant ~1952), alors que la plupart des autres eaux sont issues de la recharge après ~1990. Un modèle de réservoir représentant le lac situé dans la partie Herman Impoundment de l’ancienne mine, en régime permanent et basé sur le bore, montre que 71–79% de l’eau provient des précipitations, le reste provenant de contributions hydrothermales. Les résultats de δD et δ18O pour des échantillons d’eau souterraine de six puits peu profonds sur une période de 6 mois suggèrent que l’eau de Hermann Impoundment est encore diluée entre 3% jusqu’à plus de 40% lorsqu’elle quitte le site du fait de l’infiltration d’eau météorique. Les résultats de cette étude montrent que les traceurs environnementaux constituent un outil efficace pour comprendre le régime hydrogéologique de la SBMM.
Resumen Se han utilizado datos de concentraciones de boro, cloruros, sulfatos, δD, δ18O, y 3H en muestras de aguas superficiales y subterráneas procedentes de la Mina de Mercurio Sulphur Bank (SBMM), California, USA, para estudiar los procesos geoquímicos y caracterizar la evaporación y el flujo del agua subterránea. SBMM es una mina abandonada de azufre y mercurio con un sistema hidrotermal subyacente, cercano al Lago Clear, California.Los resultados de los trazadores que no son 3H (por ejemplo, boro, cloruros, sulfatos δD, y δ18O) identifican las contribuciones de seis tipos de agua en la SBMM. Se han identificado diversos procesos, como evaporación, mezcla, entrada de agua hidrotermal y la posibilidad de intercambios isotópicos con gases hidrotermales. Los datos de tritio indican que las aguas hidrotermales y otras aguas subterráneas profundas son probablemente pre-bombas (previas a ~1952) en edad mientras que la mayoría de las otras aguas se han recargado después de ~1990. Un modelo estacionario basado en el boro de la fosa del lago Herman Impoundment indica que el 71–79% de su entrada procede de agua meteórica con restos de contribución hidrotermal. Los resultados para las muestras de aguas subterráneas procedentes de seis pozos superficiales en un periodo de 6 meses para δD y δ18O sugieren que el agua procedente de Herman Impoundment se diluye en otro 3% hasta más del 40% debido a la infiltración de agua meteórica., que sale del sitio. Los resultados de esta investigación muestran que los trazadores ambientales son una herramienta efectiva para entender el régimen hidrogeológico de la SBMM.相似文献
46.
Lake bank filtration at Nainital,India: water-quality evaluation 总被引:6,自引:2,他引:4
There are different water-supply schemes in Uttarakhand, India to tap the water from streams, rivers and lakes. At Nainital,
seven tube-wells (depths 22.6–36.7 m), located at a distance of <100 m from the lake, are being used to abstract (1) lake
water after passage through the soil and (2) subsurface water/groundwater flowing towards the lake. Water samples from the
lake and tube-wells were analyzed in monsoon and non-monsoon periods from 1997 to 2006. Total dissolved solids, EC, alkalinity
and hardness were found to be marginally greater in tube-well waters. The difference in hydrochemistry of tube-well water
was mainly due to variation in flow regimes during monsoon and non-monsoon periods. Results clearly indicate that lake water
as such is not potable as it contains unacceptable levels of organic matter in terms of COD (~44 mg/L), coliforms (~15.6 × 104 MPN/100 mL) and nutrients. Coliform bacteria and COD have not been detected in any of the tube-well water samples over the
years. Lake water, treated by sand filters did not conform to drinking water standards. These investigations have led to the
closure of the treatment facility and installation of two tube-wells in addition to the existing five tube-wells.
Résumé Il existe divers projets d’alimentation en eau dans l’état d’Uttarakhand, Inde, afin de capter l’eau de ruisseaux, de rivières et de lacs. A Nainital, sept puits tubés (profondeur de 22.6–36.7 m), situés à une distance < à 100 m du lac, sont utilisés pour prélever (1) de l’eau du lac après transit à travers le sol et (2) de l’eau de sub-surface/eau souterraine s’écoulant vers le lac. Des échantillons d’eau du lac et des puits tubés ont été analysés en périodes de mousson et de celles sans mousson 1997 à 2006. Résidu sec, C.E., alcalinité et dureté ont été trouvés marginalement supérieurs dans l’eau des puits tubés. La différence d’hydrochimie de l’eau des puits tubés était surtout due à la variation des régimes d’écoulement pendant les périodes de mousson et de celles sans mousson. Les résultats indiquent clairement que l’eau du lac en tant que telle n’est pas potable car elle contient des teneurs inacceptables de matière organique en termes de COD (~44 mg/L), de coliformes (~15.6 × 104 MPN/100 mL) et d’éléments nutritifs. Des bactéries coliformes et du COD n’ont été détectés dans aucun des échantillons d’eau de puits tubés au fil des années. L’eau du lac traitée par des filtres à sable ne se conformait pas aux normes de l’eau potable. Ces recherches ont conduit à la fermeture de l’installation de traitement et à l’implantation de deux puits tubés en plus des cinq puits existants.
Resumen En el estado de Uttarakhand, India, existen diferentes esquemas de abastecimiento de agua que explotan agua de arroyos, ríos y lagos. En Nainital, siete pozos (profundidades entre 22.6–36.7 m), ubicados a una distancia de <100 m del lago, se usan para extraer (1) agua del lago luego de su pasaje a través del suelo y (2) agua superficial y subterránea que fluye hacia el lago. En períodos de monzón y de no monzón de 1997 a 2006 se han analizado muestras de agua del lago y de las captaciones. Se halló que el agua de los pozos es ligeramente mayor en términos del total de sólidos disueltos, la conductividad eléctrica, la alcalinidad y la dureza. La diferencia en la hidroquímica del agua de las perforaciones se debe principalmente a la variación de los regímenes de flujo durante los períodos de monzón y de no monzón. Los resultados claramente indican que el agua del lago no es potable por su contenido inaceptable de materia orgánica medida como demanda de carbono orgánico/oxígeno –DCO- (~44 mg/L), coliformes (~15.6 × 104 NMP/100 mL) y nutrientes. En el período, no se han detectado bacterias coliformes ni DCO en las muestras de agua de las captaciones. El agua del lago, tratada con filtros de arena, no conformó los estándares de agua para bebida. Estas investigaciones han demostrado la necesidad de clausurar las instalaciones de tratamiento y la adición de dos captaciones a las cinco ya existentes.相似文献
47.
This article presents a micromechanical approach to the problem of unsaturated water flow in heterogeneous porous media in
transient conditions. The numerical formulation is based on the two-scale model obtained previously by periodic homogenization.
It allows for a coupled solution of the non-linear flow equations at macroscopic and microscopic scales and takes into account
the macroscopic anisotropy of the medium and the local non-equilibrium of the capillary pressure. The model was applied to
simulate two-dimensional water infiltration at constant flux into an initially dry medium containing inclusions of square
and rectangular shapes. The numerical results showed the influence of the inclusion–matrix conductivity ratio and the local
geometry on the macroscopic behavior. The influence of the conductivity ratio manifested itself by the acceleration or retardation
of the onset of the macroscopic water flux at the outlet, while the local geometry (anisotropy) significantly affected the
macroscopic spatial distribution of the water flux. Such type of approach can be extended to simulate coupled phenomena (for
example hydro-mechanical problems) with evolving local geometry. 相似文献
48.
Water and sediment samples collected from the Gomti River, a tributary of the Ganges River system, during the postmonsoon season have been analyzed to estimate major elemental chemistry. Water chemistry of the River Gomti shows almost monotonous spatial distribution of various chemical species, especially because of uniform presence of alluvium Dun gravels throughout the basin. The river annually transports 0.34×106 tonnes of total suspended material (TSM) and 3.0×106 tonnes of total dissolved solids (TDS), 69 percent of which is accounted for by bicarbonate ions only. Samples collected downstream of the city of Lucknow show the influence of anthropogenic loadings for a considerable distance in the river water. Na+, Cl–, and SO4
2– concentrations build up downstream. The bed sediment chemistry is dominated by Si (36 percent), reflecting a high percentage of detrital quartz, which makes up about 74 percent of the mineralogy of the bed sediments in the River Gomti. The average Kjeldahl nitrogen concentration (234 g/g) indicates indirectly the amount of organic matter in the sediments. The Hg concentration in sediments has been found to be higher (average 904 ppb) than the background value. The suspended sediments are well sorted, very finely skewed, and extremely leptokurtic, indicating a low energy condition of flow in the Gomti River. The influence of chemical loads in the Gomti has been found to be small or nonexistent on the Ganges River, perhaps because the water discharge of the Gomti (1.57 percent) to the Ganges is quite low. 相似文献
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50.
The self-potential method can be applied to evaluate the degree of water seepage into earth or rockfill dams. Spatial distribution of measured self-potential data can indicate possible anomalous water flow. Phenomena, such as piping, can be modelled as cylindrical bodies. Internal erosion can develop structures, which can be represented by a sphere or point source. Differential settlement in the dam structure occasionally creates horizontal fractures, which require equivalent geometrical body formula. An equation, which allows the calculation of a self-potential profile over a horizontal contact, was developed. This equation can also be applied to the inspection of water flow into horizontal drainage filters. When inverse interpretation returns bodies of relatively small amplitudes, then their probability can be tested statistically. A test, based on cross-correlation between a modelled curve and field data, can be used to evaluate their existence at a given probability level. An acceptance criterion is computed, using the concept of likelihood coefficient. The equation was applied to two case histories. The first is an example of water flow evaluation into a horizontal drainage filter. Several anomalous bodies were interpreted from residual self-potential data, i.e. from the difference between the theoretical response of the filter and the measured self-potential values, then, most of the interpreted bodies were statistically tested. The second case deals with detection and evaluation of a horizontal fissure. The interpreted parameters of the detected body corresponded well to a horizontal fracture found when the water level in the reservoir was lowered. 相似文献