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81.
Zhou Haiyan Zhou Xun Chai Rui Yu Lan Liu Chunhui Li Liangping 《Environmental Geology》2008,53(7):1483-1489
Thermal groundwater occurs in bedrock aquifers consisting of the dolomite of the Wumishan Group of the Jixianin System and
the Cambrian carbonate in the Xiaotangshan geothermal field near the northern margin of the North China Plain, China. The
hot water in the geothermal field of basin-type discharges partly in the form of the Xiaotangshan hot spring under natural
conditions. The hot water has TDS of less than 600 mg/L and is of Na·Ca-HCO3 type. The geothermal water receives recharge from precipitation in the mountain area with elevation of about 500 m above
sea level to the north of the spring. Thermal groundwater flows slowly south and southeast through a deep circulation with
a residence time of 224 years estimated with the Ra–Rn method. The Xiaotangshan hot spring dried up in the middle of the 1980s
owing to the increasing withdrawal of the hot water in the geothermal field in the past decades. The water level of the geothermal
system still falls continually at an annual average rate of about 2 m, although water temperature changes very little, indicating
that the recharge of such a geothermal system of basin-type is limited. Over-exploitation has a dramatic impact on the geothermal
system, and reduction in exploitation and reinjection are required for the sustainable usage of the hot water. 相似文献
82.
Phosphorus transport in shallow groundwater in peri-urban Kampala, Uganda: results from field and laboratory measurements 总被引:1,自引:0,他引:1
To understand Phosphorus (P) sources and transport processes in the subsurface in Bwaise III Parish, Kampala, P attenuation
and adsorption capacities of soils were studied in situ and from laboratory measurements. Relationships between sorption parameters
and soil matrix properties, rates and mechanism of the adsorption process and soil P fractions were also investigated. P was
generally higher in the wet than the dry season, but for both seasons, the maximum was 5 mgP/l. P transport mechanisms appeared
to be a combination of adsorption, precipitation, leaching from the soil media and by colloids with the latter two playing
an important role in the wet season. The sorption process comprised two phases with the first stage rate constants being about
fourfold those of the second stage. The Langmuir isotherm described the sorption data well (R
2 ≥ 0.95) with the second soil layer exhibiting the highest sorption maximum (C
max) (average value 0.6 ± 0.17 mgP/gDW). The best prediction of C
max had organic carbon, Ca, available P and soil pH. Residual P consisting mostly of organics was the main fraction in all the
layers followed by inorganic HCl-P and NaOH-P in the top and middle layers, respectively. Loosely bound P (NH4Cl-P) was the least fraction (<0.4% of total P) in all layers indicating the high binding capacity of P by the soils. The
study results suggest that P dynamics is related to Ca, Fe and organic carbon content of the soils. 相似文献
83.
Response of groundwater chemistry to water deliveries in the lower reaches of Tarim River,Northwest China 总被引:2,自引:0,他引:2
Yongjin Chen Kefa Zhou Yaning Chen Weihong Li Jiazhen Liu Tao Wang 《Environmental Geology》2008,53(6):1365-1373
In this paper, we analysed the monitored data from nine groundwater-monitoring transects in the lower reaches of Tarim River
during the five times of stream water deliveries to the river transect where the stream flow ceased. The results showed that
the groundwater depth in the lower reaches of Tarim River rose from −9.30 m before the conveyances to −8.17 and −6.50 m after
the first and second conveyances, −5.81 and −6.00 m after the third and fourth the conveyance, and −4.73 m after the fifth.
The horizontal extent of groundwater recharge was gradually enlarged along both sides of the channel of conveyance, i.e.,
from 250 m in width after the first conveyance to 1,050 m away from the channel after the fourth delivery. With the rising
groundwater level, the concentrations of major anions Cl−, SO42− and cations Ca2+, Mg2+, Na+, as well as total dissolved solids (TDS) in groundwater underwent a significant change. The spatial variations in groundwater
chemistry indicated that the groundwater chemistry at the transect near Daxihaizi Reservoir changed earlier than that farther
from it. In the same transect, the chemical variations were earlier in the monitoring well close to watercourse than that
farther away from the stream. In general, the concentration of the major ions and TDS at each monitoring well increased remarkably
when the water delivery started, and decreased with the continued water delivery, and then increased once again at the end
of the study period. Hence, the whole study period may be divided into three stages: the initial stage, the intermediate stage
and the later stage. According to the three stages of groundwater chemistry reaction to water delivery and the relationships
between groundwater chemical properties and groundwater depths, we educe that under the situation of water delivery, the optimum
groundwater depth in the lower reaches of the Tarim River should be −5 m. 相似文献
84.
A Triassic carbonate unit has been intensively drained by zinc and lead ore mines and numerous borehole fields since the nineteenth
century. Its groundwater recharge has increased due to: pumping of water from boreholes, mining activity, and urbanization.
An approach to determine the amounts of the recharge at a variety of spatial scales is presented in the paper. Different methods
were used to identify and quantify recharge components on a regional and local scale: mathematical modelling was performed
for four aquifers included in an aquifer system, an analytical estimation based on the assumption that an average recharge
is equal to the average discharge of the hydrogeological system—for six man-made drainage centres, and the method of water
level fluctuation (WLF) was applied in one observation borehole. Results of modelling have been supplemented by observation
of environmental tracers (δ18O, δ2H, 3H), noble gases temperatures, and 4Heexc in groundwater. The regional aquifer’s current recharge according to estimations performed by means of modelling varies from
39 to 101 mm/year on average. Depending on the aquifer site the average precipitation ranges from 779 to 864 mm/year. In the
confined part of the aquifer average recharge ranges from 26 to 61 mm/year. Within outcrops average recharge varies from 96
to 370 mm/year. Current recharge estimated by the analytical method for man-made drainage centres varies from 158 up to 440 mm/year.
High values are caused by different recharge sources like precipitation, induced leakage from shallow aquifers, and water
losses from streams, water mains and sewer systems. Pumping of water, mining and municipal activities constitute additional
factors accounting for the intensified recharge. 相似文献
85.
86.
Greening as strategic development in industrial change - Why companies participate in eco-networks 总被引:1,自引:0,他引:1
Eckhard Störmer 《Geoforum》2008,39(1):32-47
Networking between companies and other regional key actors has grown into a widespread instrument for economic development since the 1990s. Participatory networks have formed the concept for many activities of Local Agenda 21. Simultaneously, economic geography has focused on network theories to explain innovation in and the economic success of regions.This article focuses on the reasons why individual actors participate in environmentally oriented information networks. The questions approached are: Does the concept of learning within networks influence a firm’s development? How do the participants interact with each other? What effects do the networks have on their environment (arenas)?The changing arenas of a firm are analysed with regard to environmental concerns. These changes need to be anticipated for reliable strategies. To gain information and knowledge about current behaviour and activities, the functions of networks as learning platforms are discussed. Drawing upon arguments from different network theories, the motivations of participating in a network are threefold: actor and firm oriented, network internal (inter-firm), and network external. From these, a generic target cube of network motivations and actions is set up.The concept is reviewed by examining 12 ‘regional environmental information-oriented corporation networks’ (RUN) in the Greater Munich Area. The empirical material reveals that this type of network does not provide a guarantee for significant improvements in a firm’s environmental behaviour. However, participants learn about best practices while pursuing explicit or implicit aims as to influence their arenas. 相似文献
87.
Until recently the traditional spatial configuration of the European geography was based upon the core-periphery model. The
‘pentagon’, broadly defined as lying between London, Paris, Milan, Munich and Hamburg, was seen as the core area characterised
by having the highest concentration of economic development in the European Union (EU), with the remainder of the European
territory viewed as peripheral, albeit to varying degrees. In a number of cases such peripheral areas equated with clear regional
disparities. The elaboration of the European Spatial Development Perspective (ESDP) (CEC, European spatial development perspective, towards balanced and sustainable development in the territory of the
European Union, 1999) challenged this core-periphery model. European spatial planning policies, aimed at encouraging social
and economic, and with ever increasing importance, territorial cohesion, seek amongst other aspects to encourage the development
of a balanced and polycentric urban system. This paper adopts a network analysis approach to the analysis of air passenger
flows between some 28 principal European metropolitan urban regions. The evaluation of these flows contributes to an enhanced
comprehension of the spatial dynamics of the European metropolitan territory which goes beyond that deriving from the more
standard analyses of the individual components of the urban system. Several indicators are used, deriving from gravitational
modelling techniques, to analyse the complexity of the air passenger flows. A multidimensional scaling (MDS) technique is
introduced in order to interpret and visualise the resulting spatial configuration and positioning of the different metropolitan
centres within the conceptual European ‘space of air passenger flows’, thereby contrasting with the more traditional map-based
geographical image of Europe, based upon Cartesian coordinates.
相似文献
Malcolm C. BurnsEmail: |
88.
东营凹陷牛庄洼陷沙河街组发育有超压系统,这对油气运移和聚集过程有着重要的影响。在对超压系统现今发育特征研究的基础上,本文运用约束下数值模拟方法对牛庄洼陷超压系统的演化规律进行研究,并探讨了超压系统的主要形成机制。牛庄洼陷在沙河街组四段、沙河街组三段的下亚段和中亚段存在着超压系统,最大压力系数可以达到1.8,最大剩余压力超过了20MPa。自沙三段上亚段沉积期开始,超压系统开始发育。到东营组沉积期末,超压系统经历了大约10Ma的泄压过程。自新近系馆陶组沉积期,超压系统再次迅速增压,逐渐接近现今发育状况。上覆地层沙三段上亚段高沉积速率导致了超压系统的形成和早期剩余压力的增加,而水热增压和烃类物质大量生成联合造成超压系统晚期迅速增压。超压系统演化规律揭示出在油气主要运移期研究区古异常流体压力的分布状况,这为进一步开展牛庄洼陷油气运移和聚集过程的动力学研究提供了理论依据。 相似文献
89.
M. Mejías J. Garcia-Orellana J. L. Plata M. Marina E. Garcia-Solsona B. Ballesteros P. Masqué J. López C. Fernández-Arrojo 《Environmental Geology》2008,54(3):521-536
A methodology for the characterization of deep carbonate aquifers has been developed and applied to El Maestrazgo Jurassic
aquifer in Castellón, Spain. Characterization of these aquifer formations, located at more than 300 m deep, consisted of a
previous phase of compilation, analysis and synthesis of the existing information about the area, followed by a coordinated
combination of different speciality studies: geology, stratigraphy, structural analysis, hydrogeology, hydrochemistry, geophysics
and remote sensing. Geological studies included geological mapping, definition of stratigraphical units and facies and structural
analysis. The aim of the hydrogeology study was to define aquifer formations, recharge area, aquifer points inventory and
groundwater flow directions for the establishment of piezometric and water quality observation nets. Special techniques were
applied, like thermal infrared aerial images and the evaluation of submarine groundwater discharge by means of natural radium
isotopes. Hydrochemical techniques, including majority elements characterization and stable isotopes (18O, 2H and 3H) determination, allowed classifying hydrochemical facies and establishing a renewal pattern for water within the system.
Geophysics was useful in determining the aquifer geometry, the features of the basement and the petrophysical characteristics
of the geological formations. Preliminary results show an important tectonic complexity and the possibilities for groundwater
uses in the area of study. 相似文献
90.
Soil erosion susceptibility assessment and validation using a geostatistical multivariate approach: a test in Southern Sicily 总被引:2,自引:0,他引:2
A certain number of studies have been carried out in recent years that aim at developing and applying a model capable of assessing
water erosion of soil. Some of these have tried to quantitatively evaluate the volumes of soil loss, while others have focused
their efforts on the recognition of the areas most prone to water erosion processes. This article presents the results of
a research whose objective was that of evaluating water erosion susceptibility in a Sicilian watershed: the Naro river basin.
A geomorphological study was carried out to recognize the water erosion landforms and define a set of parameters expressing
both the intensity of hydraulic forces and the resistance of rocks/soils. The landforms were mapped and classified according
to the dominant process in landsurfaces affected by diffuse or linear water erosion. A GIS layer was obtained by combining
six determining factors (bedrock lithology, land use, soil texture, plan curvature, stream power index and slope-length factor)
in unique conditions units. A geostatistical multivariate approach was applied by analysing the relationships between the
spatial distributions of the erosion landforms and the unique condition units. Particularly, the density of eroded area for
each combination of determining factors has been calculated: such function corresponds, in fact, to the conditional probability
of erosion landforms to develop, under the same geoenvironmental conditions. In light of the obtained results, a general geomorphologic
model for water erosion in the Naro river basin can be depicted: cultivated areas in clayey slopes, having fine-medium soil
texture, are the most prone to be eroded; linear or diffuse water erosion processes dominate where the topography is favourable
to a convergent or divergent runoff, respectively. For each of the two erosion process types, a susceptibility map was produced
and submitted to a validation procedure based on a spatial random partition strategy. Both the success of the validation procedure
of the susceptibility models and the geomorphological coherence of the relationships between factors and process that such
models suggest, confirm the reliability of the method and the goodness of the predictions. 相似文献