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351.
Urbanization and its impact on groundwater: a remote sensing and GIS-based assessment approach 总被引:1,自引:0,他引:1
The perils of unplanned urbanization and increasing pressure of human activities on hydro-geomorphologic system often result
in modification of the existing recharge mechanism, which leads to many environmental consequences. In the present research,
an attempt has been made to investigate the applicability of remote sensing and geographical information system (GIS) in dealing
with spatial and temporal variability of dynamic phenomena, like urbanization and its impact on groundwater. This paper covers
primarily, quantitative and qualitative impacts of urban growth on the behavior of aquifer in Ajmer city (India). Urban growth
of the Ajmer city in last 17 years has been estimated from the satellite images. Database related to urbanization and groundwater
has been created in GIS. Groundwater recharge has been computed using a water balance approach known as Water Level Fluctuation
Methodology. Recharge estimation methodology has been implemented in GIS to introduce the spatial variability of hydro-geological
characteristics. Further, temporal and spatial variations in groundwater quality and quantity have been correlated with urban
growth using overlay analysis in GIS. The study reveals a general decline in water table and quality with urbanization. Further,
remote sensing and GIS technologies have been found useful in assessment of spatial and temporal phenomena of urbanization
and its impact on groundwater system. 相似文献
352.
353.
The Role of Abatement Costs in GHG Permit Allocations: A Global Stabilization Scenario Analysis 总被引:1,自引:0,他引:1
Kathleen Vaillancourt Richard Loulou Amit Kanudia 《Environmental Modeling and Assessment》2008,13(2):169-179
Our objective is to propose permit allocation schemes that lead to a fair distribution of the net abatement cost among regions
in a global greenhouse gas (GHG) stabilization scenario. We use a detailed technology-based energy model, World-MARKAL, to
determine efficient abatement decisions, and to calculate the regional gross abatement costs (before permit allocation and
trading). The net abatement costs are then calculated and used for different permit allocation schemes. 相似文献
354.
Because of fast urban sprawl, land use competition, and the gap in available funds and needed funds, municipal decision makers
and planners are looking for more cost-effective and sustainable ways to improve their sewer infrastructure systems. The dominant
approaches have turned to planning the sanitary sewer systems within a regional context, while the decentralized and on-site/cluster
wastewater systems have not overcome the application barriers. But regionalization policy confers uncertainties and risks
upon cities while planning for future events. Following the philosophy of smart growth, this paper presents several optimal
expansion schemes for a fast-growing city in the US/Mexico borderlands—the city of Pharr in Texas under uncertainty. The waste
stream generated in Pharr is divided into three distinct sewer sheds within the city limit, including south region, central
region, and north region. The options available include routing the wastewater to a neighboring municipality (i.e., McAllen)
for treatment and reuse, expanding the existing wastewater treatment plant (WWTP) in the south sewer shed, and constructing
a new WWTP in the north sewer shed. Traditional deterministic least-cost optimization applied in the first stage can provide
a cost-effective and technology-based decision without respect to associated uncertainties system wide. As the model is primarily
driven by the fees charged for wastewater transfer, sensitivity analysis was emphasized by the inclusion of varying flat-rate
fees for adjustable transfer schemes before contracting process that may support the assessment of fiscal benefits to all
parties involved. Yet uncertainties might arise from wastewater generation, wastewater reuse, and cost increase in constructing
and operating the new wastewater treatment plant simultaneously. When dealing with multiple sources of uncertainty, the grey
mixed integer programming (GIP) model, formulated in the second stage, can further allow all sources of uncertainties to propagate
throughout the optimization context, simultaneously leading to determine a wealth of optimal decisions within a reasonable
range. Both models ran for three 5-year periods beginning in 2005 and ending in 2020. The dynamic outputs of this analysis
reflect the systematic concerns about integrative uncertainties within this decision analysis, which enable decision makers
and stakeholders to make all-inclusive decisions for sanitary sewer system expansion in an economically growing region. 相似文献
355.
Matteo Carpentieri Paolo Giambini Andrea Corti 《Environmental Modeling and Assessment》2008,13(3):415-429
Several wind tunnel experiments of tracer dispersion from reduced-scale landfill models are presented in this paper. Different
experimental set-ups, hot-wire anemometry, particle image velocimetry and tracer concentration measurements were used for
the characterisation of flow and dispersion phenomena nearby the models. The main aim of these experiments is to build an
extensive experimental data set useful for model validation purposes. To demonstrate the potentiality of the experimental
data set, a validation exercise on several mathematical models was performed by means of a statistical technique. The experiments
highlighted an increase in pollutant ground level concentrations immediately downwind from the landfill because of induced
turbulence and mean flow deflection. This phenomenon turns out to be predominant for the dispersion process. Tests with a
different set-up showed an important dependence of the dispersion phenomena from the landfill height and highlighted how complex
orographic conditions downwind of the landfill do not affect significantly the dispersion behaviour. Validation exercises
were useful for model calibration, improving code reliability, as well as evaluating performances. The Van Ulden model proved
to give the most encouraging results. 相似文献
356.
We present a new mathematical programming framework that is adaptable to a variety of spatially explicit landscape problems
in environmental investment, conservation, and land-use planning, transport planning, and agriculture. As part of capturing
spatial interdependencies, the framework considers decision variables at two levels, finely spaced grid cells and landholdings.
We applied the framework to an environmental investment problem using objective functions representing biodiversity and carbon
sequestration. We also tested the model to optimize the path of a road through part of the landscape. Using the Nambucca case
study in eastern Australia, we applied a hybrid greedy randomised adaptive search procedure (GRASP) to find solutions to the
model. 相似文献
357.
Felix Deutsch Jean Vankerkom Liliane Janssen Filip Lefebre Clemens Mensink Frans Fierens Gerwin Dumont Edward Roekens 《Environmental Modeling and Assessment》2008,13(3):431-437
The European Operational Smog (EUROS) integrated air quality modelling system has been extended to model fine particulate
matter (PM). From an extended literature study, the Caltech Atmospheric Chemistry Mechanism and the Model of Aerosol Dynamics,
Reaction, Ionisation and Dissolution were selected and recently coupled to EUROS. Currently, modelling of mass and chemical
composition of aerosols in two size fractions (PM2.5 and PM10–2.5) is possible. The chemical composition is expressed in terms of seven components: ammonium, nitrate, sulphate, elementary
carbon, primary inorganic compounds, primary organic compounds and secondary organic compounds. Calculated PM10 concentrations and chemical composition are presented for two summer months of the year 2003 (1 July to 31 August). 相似文献
358.
We describe the development and parameterization of a grid-based model of African savanna vegetation processes. The model
was developed with the objective of exploring elephant effects on the diversity of savanna species and structure, and in this
formulation concentrates on the relative cover of grass and woody plants, the vertical structure of the woody plant community,
and the distribution of these over space. Grid cells are linked by seed dispersal and fire, and environmental variability
is included in the form of stochastic rainfall and fire events. The model was parameterized from an extensive review of the
African savanna literature; when available, parameter values varied widely. The most plausible set of parameters produced
long-term coexistence between woody plants and grass, with the tree–grass balance being more sensitive to changes in parameters
influencing demographic processes and drought incidence and response, while less sensitive to fire regime. There was considerable
diversity in the woody structure of savanna systems within the range of uncertainty in tree growth rate parameters. Thus,
given the paucity of height growth data regarding woody plant species in southern African savannas, managers of natural areas
should be cognizant of different tree species growth and damage response attributes when considering whether to act on perceived
elephant threats to vegetation. 相似文献
359.
Laboratory-scale studies were aimed at elucidating the physico-chemical aspects on the removal process of crystal violet (CV) from waters and solid substrates. The laponite clay (RD) and sand were chosen for the double aim at investigating them as CV adsorbents for water treatment and as substrates which mime the soil components. Sand is very effective in removing CV from waters. The cyclodextrins (CDs) were exploited as solubility-enhancement agents to remove CV from the solid substrates. They are powerful solvent media because they extract the CV from sand forming water-soluble CV/CD inclusion complexes and do not show affinity for sand. Optimum performance was shown by the modified CDs (i.e. hydroxypropyl-β-cyclodextrin and methyl-β-cyclodextrin). A linear correlation between the logarithm of the equilibrium constant for the CV/CD inclusion complexes formation (Kcpx) and the maximum amount of CV extracted from sand in the columns experiments at a flow rate of 1.5 ml min−1 was drawn. This relationship predicts that CDs with Kcpx < 180 M−1 are not suitable for CV removal from sand. CDs failed to displace CV from RD because they generate the formation of RD clusters where CV remains entrapped. 相似文献
360.
The acid-base properties of humic acids (HAs) and fulvic acids (FAs) isolated from composted sewage sludge (CS), thermally-dried sewage sludge (TS), soils amended with either CS or TS at a rate of 80 t ha(-1)y(-1) for 3y and the corresponding unamended soil were investigated by use of potentiometric titrations. The non-ideal competitive adsorption (NICA)-Donnan model for a bimodal distribution of proton binding sites was fitted to titration data by use of a least-squares minimization method. The main fitting parameters of the NICA-Donnan model obtained for each HA and FA sample included site densities, median affinity constants and widths of affinity distributions for proton binding to low and high affinity sites, which were assumed to be, respectively, carboxylic- and phenolic-type groups. With respect to unamended soil HA and FA, the HAs and FAs from CS, and especially TS, were characterized by smaller acidic functional group contents, larger proton binding affinities of both carboxylic- and phenolic-type groups, and smaller heterogeneity of carboxylic and phenolic-type groups. Amendment with CS or TS led to a decrease of acidic functional group contents and a slight increase of proton binding affinities of carboxylic- and phenolic-type groups of soil HAs and FAs. These effects were more evident in the HA and FA fractions from CS-amended soil than in those from TS-amended soil. 相似文献