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881.
Zaragoza city is located in the central Ebro Basin, in the Iberian Peninsula. The fluvial terraces formed by the Ebro River
present a valuable resource of sand and gravel deposits. However, taking advantage of these available resources implies conflicts
with other land use interests like urban and industrial development as well as agricultural use, which has also traditionally
occupied the alluvial terraces. These deposits represent a substantial groundwater resource that should be preserved for future
generations. The development of spatial decision support systems (SDSS) has greatly assisted efforts for solving land-use
conflicts. These systems combine the benefits of geographic information systems (GIS) and decision support methodologies and
are therefore suitable to manage sustainable development of urban areas. In this contribution, an extraction suitability map
taking into consideration a variety of environmental criteria is created with the help of a SDSS. The method used is the analytical
hierarchy process which is integrated in ArcGIS. Areas most suitable to sand and gravel extraction are located in the high
terraces, and in those terraces covered by pediments where the thickness of resource is relatively high. These areas are far
from valuable natural areas, outside areas most vulnerable to groundwater contamination, and beneath soils with poor irrigation
characteristics. 相似文献
882.
A modified DRASTIC model for Siting Confined Animal Feeding Operations in Williams County,Ohio, USA 总被引:1,自引:0,他引:1
Three of DRASTIC’s parameters (Depth to Water, Soil Media, and Topography) were modified and another parameter was added (land
use/land cover) to the model to determine the potential impact on groundwater from Confined Animal Feeding Operations (CAFO)
manure lagoon settings and manure application as fertilizer. Williams County is a mostly agricultural county located in northwest
Ohio, USA. It currently has three CAFOs, all dairy, with the possibility of the construction of a multi-million chicken egg
CAFO in the near future. A Geographic Information System (GIS) was utilized to modify the Ohio Department of Natural Resources
(ODNR) DRASTIC map for the county to fully assess the county-wide pollution potential of CAFOs. The CAFO DRASTIC map indicates
that almost half of Williams County has elevated groundwater pollution potential. The rest of the county, primarily the southeast
corner, has lower CAFO groundwater pollution potential. Future CAFO development within the county should focus on the southeastern
portion of the county where the groundwater table is deeper, and the aquifer is composed of shale substrate with low hydraulic
conductivity. The CAFO DRASTIC results are intended to be used as a screening tool and are not to replace site-specific hydrogeologic
investigations. 相似文献
883.
Quick-look assessments to identify optimal CO2 EOR storage sites 总被引:1,自引:0,他引:1
Vanessa Núñez-López Mark H. Holtz Derek J. Wood William A. Ambrose Susan D. Hovorka 《Environmental Geology》2008,54(8):1695-1706
A newly developed, multistage quick-look methodology allows for the efficient screening of an unmanageably large number of
reservoirs to generate a workable set of sites that closely match the requirements for optimal CO2 enhanced oil recovery (EOR) storage. The objective of the study is to quickly identify miscible CO2 EOR candidates in areas that contain thousands of reservoirs and to estimate additional oil recovery and sequestration capacities
of selected top options through dimensionless modeling and reservoir characterization. Quick-look assessments indicate that
the CO2 EOR resource potential along the US Gulf Coast is 4.7 billion barrels, and CO2 sequestration capacity is 2.6 billion metric tons. In the first stage, oil reservoirs are screened and ranked in terms of
technical and practical feasibility for miscible CO2 EOR. The second stage provides quick estimates of CO2 EOR potential and sequestration capacities. In the third stage, a dimensionless group model is applied to a selected set
of sites to improve the estimates of oil recovery and storage potential using appropriate inputs for rock and fluid properties,
disregarding reservoir architecture and sweep design. The fourth stage validates and refines the results by simulating flow
in a model that describes the internal architecture and fluid distribution in the reservoir. The stated approach both saves
time and allows more resources to be applied to the best candidate sites. 相似文献
884.
The Hill Country of Central Texas, USA, is undergoing rapid socioeconomic development, but environmental management of this
region is hampered by misconceptions about local bedrock, soils, terrain, and hydrologic processes. The Hill Country is underlain
mostly by Glen Rose Limestone (Lower Cretaceous) and exhibits a stepped terrain, which has been incorrectly attributed to
alternating hard and soft bedrock strata. Other characteristics mistakenly attributed to this landscape include thin soils
with scant water-retention capabilities, and rapid runoff as the dominant hydrologic process. This report presents new findings:
unweathered bedrock is well indurated, but interbeds exhibit variable weathering rates. Recessive slopes (“risers”) on this
stepped terrain result from rapid deterioration of strata having generally heterogeneous depositional fabrics (bioturbation
and irregular clay partings) in contrast to ledge-forming strata having homogeneous fabrics. A stony regolith is thus formed
beneath risers, providing porous and permeable ground that retards runoff and promotes the formation of moderately deep to
deep (two-tiered) regolith/soil zones. These surficial materials on local steep slopes compose important natural environmental
buffers; they support diverse biota and enhanced geochemical cycling of nutrients; they also exhibit significant water retention
and enhanced erosion abatement. Proper land management demands recognition of these attributes in the siting, design, and
construction of facilities. 相似文献
885.
S. Miko G. Koch S. Mesić M. Šparica-Miko M. Šparica R. Čepelak A. Bačani P. Vreča T. Dolenec S. Bergant 《Environmental Geology》2008,55(3):517-537
Due to their balneotherapeutic features, the organic-rich sediments in Makirina Cove are an important source of healing mud.
An environmental geochemistry approach using normalization techniques was applied to evaluate the anthropogenic contribution
of trace metals to sediments used as healing mud. Sediment geochemistry was found to be associated with land-use change and
storm events, as well as with proximity of a road with heavy traffic in the summer months. Local valley topography preferentially
channels lithogenic and pollutant transport to the cove. Concentrations and distribution of trace metals indicate lithogenic
(Ni, Cr, Co) and anthropogenic (Pb, Cu, Zn and Se) contributions to the sediments. The calculation of enrichment factors indicates
a moderate (EFs between 2–3.5) input of anthropogenic Cu and Pb in surficial sediments to a depth of 10 cm. Patients using
the Makirina Cove sediments as healing mud could be to some extent exposed to enhanced uptake of metals from anthropogenic
sources via dermal contact. 相似文献
886.
The aim of this interdisciplinary study is to examine a component of the hydrological cycle in Galapagos by characterizing
soil properties. Nine soil profiles were sampled on two islands. Their physical and hydrodynamic properties were analyzed,
along with their mineralogical composition. Two groups of soils were identified, with major differences between them. The
first group consists of soils located in the highlands (>350 m a.s.l.), characterized by low hydraulic conductivity (<10−5 m s−1) and low porosity (<25%). These soils are thick (several meters) and homogeneous without coarse components. Their clay fraction
is considerable and dominated by gibbsite. The second group includes soils located in the low parts of the islands (<300 m
a.s.l.). These soils are characterized by high hydraulic conductivity (>10−3 m s−1) and high porosity (>35%). The structure of these soils is heterogeneous and includes coarse materials. The physical properties
of the soils are in good agreement with the variations of the rainfall according to the elevation, which appears as the main
factor controlling the soil development. The clayey alteration products constrain soils physical and hydrodynamic properties
by reducing the porosity and consequently the permeability and also by increasing water retention. 相似文献
887.
The Cu–Co–Ni Texeo mine has been the most important source of Cu in NW Spain since Roman times and now, approximately 40,000 m3 of wastes from mine and metallurgical operations, containing average concentrations of 9,263 mg kg−1 Cu, 1,100 mg kg−1 As, 549 mg kg−1 Co, and 840 mg kg−1 Ni, remain on-site. Since the cessation of the activity, the abandoned works, facilities and waste piles have been posing
a threat to the environment, derived from the release of toxic elements. In order to assess the potential environmental pollution
caused by the mining operations, a sequential sampling strategy was undertaken in wastes, soil, surface and groundwater, and
sediments. First, screening field tools were used to identify hotspots, before defining formal sampling strategies; so, in
the areas where anomalies were detected in a first sampling stage, a second detailed sampling campaign was undertaken. Metal
concentrations in the soils are highly above the local background, reaching up to 9,921 mg kg−1 Cu, 1,373 mg kg−1 As, 685 mg kg−1 Co, and 1,040 mg kg−1 Ni, among others. Copper concentrations downstream of the mine works reach values up to 1,869 μg l−1 and 240 mg kg−1 in surface water and stream sediments, respectively. Computer-based risk assessment for the site gives a carcinogenic risk
associated with the presence of As in surface waters and soils, and a health risk for long exposures; so, trigger levels of
these elements are high enough to warrant further investigation. 相似文献
888.
Regional distribution pattern of groundwater heavy metals resulting from agricultural activities 总被引:18,自引:0,他引:18
Contaminations of groundwater by heavy metals due to agricultural activities are growing recently. The objective of this study
was to evaluate and map regional patterns of heavy metals (Cd, Zn and Cu) in groundwater on a plain with high agricultural
activities. The study was conducted to investigate the concentration of heavy metals and distribution in groundwater in regions
of Shush Danial and Andimeshk aquifers in the southern part of Iran. Presently, groundwater is the only appropriate and widely
used source of drinking water for rural and urban communities in this region. The region covers an area of 1,100 km2 between the Dez and Karkhe rivers, which lead to the Persian Gulf. For this study, the region was divided into four sub-regions
A, B, C and D. Additionally, 168 groundwater samples were collected from 42 water wells during the earlier months of 2004.
The flame atomic absorption spectrometry (AAS-Flame) was used to measure the concentration of heavy metals in water samples
and the Surfer software was used for determination of the contour map of metal distribution. The results demonstrated that
in all of the samples, Cd and Zn concentrations were below the EPA MCLG and EPA secondary standard, respectively. However,
the Cu contents of 4.8 % of all samples were higher than EPA MCL. It is also indicated that the concentrations of metals were
more pronounced at the southern part of the studied region than at the others. The analysis of fertilizers applied for agricultural
activities at this region also indicated that a great majority of the above-mentioned heavy metals were discharged into the
environment. Absence of confining layers, proximity to land surface, excess agricultural activities in the southern part and
groundwater flow direction that is generally from the north to the southern parts in this area make the southern region of
the Shush plain especially vulnerable to pollution by heavy metals than by other contaminants. 相似文献
889.
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
890.
Spatial data for landslide susceptibility, hazard, and vulnerability assessment: An overview 总被引:30,自引:0,他引:30
The aim of this paper is to discuss a number of issues related to the use of spatial information for landslide susceptibility, hazard, and vulnerability assessment. The paper centers around the types of spatial data needed for each of these components, and the methods for obtaining them. A number of concepts are illustrated using an extensive spatial data set for the city of Tegucigalpa in Honduras. The paper intends to supplement the information given in the “Guidelines for Landslide Susceptibility, Hazard and Risk Zoning for Land Use Planning” by the Joint ISSMGE, ISRM and IAEG Technical Committee on Landslides and Engineered Slopes (JTC-1). The last few decades have shown a very fast development in the application of digital tools such as Geographic Information Systems, Digital Image Processing, Digital Photogrammetry and Global Positioning Systems. Landslide inventory databases are becoming available to more countries and several are now also available through the internet. A comprehensive landslide inventory is a must in order to be able to quantify both landslide hazard and risk. With respect to the environmental factors used in landslide hazard assessment, there is a tendency to utilize those data layers that are easily obtainable from Digital Elevation Models and satellite imagery, whereas less emphasis is on those data layers that require detailed field investigations. A review is given of the trends in collecting spatial information on environmental factors with a focus on Digital Elevation Models, geology and soils, geomorphology, land use and elements at risk. 相似文献