1,720,960 research outputs found
Planning actions for controlling saltwater intrusion in coupling SEAWAT and Global Interactive Response Surface: the Nauru island case study
No full textPlanning infrastructural measures for controlling saltwater intrusion in a coastal aquifer by Global Interactive Response Surfaces: The Nauru island case study
No full textInfiltration galleries and scavenger wells are usually constructed to control pumping based saltwater intrusion in coastal aquifers. The optimal allocation of these infrastructures can be decided by solving a multi-objective optimization problem balancing availability of fresh water supply and installation/operation costs, where the effects of different design options on the planning objectives are simulated through a high fidelity model of the flow and transport processes. The incorporation of these simulation models within an optimization-based planning framework is not always straightforward because of the computational requirements of the model itself and the computational limitations of the optimization algorithms. In this paper we explore the potential for the Global Interactive Response Surface (GIRS) methodology to overcome these technical limitations. The GIRS methodology is used to recursively build a non-dynamic emulator of the processbased model that maps the design options into the objectives values and can be used in place of the original model to more quickly explore the design option space. The approach is used to plan infrastructural interventions for controlling saltwater intrusion and ensuring sustainable groundwater supply for Nauru, a Pacific island republic in Micronesia. GIRS is used to emulate a SEAWAT density driven groundwater flow-and-transport simulation model. The evaluation results show the potential applicability of the proposed approach for optimal planning of coastal aquifers
Optimal design of saltwater intrusion control systems by Global Interactive Response Surfaces: the Nauru island case study
No full textAssessment of sources of PCE contamination in groundwater using a Monte Carlo method in the Functional Urban Area of Milano
No full textWater Framework Directive and Groundwater Directive (2006/118/CE) represent the main European regulations on water resources quality, requiring the identification and management of contamination sources threatening the achievement of acceptable groundwater quality status. The sources of groundwater contamination can be classified into two different categories: 1) point sources (PS), which are identified areas releasing plumes of high/very high concentrations (i.e. hot-spots) and 2) multiple-point sources (MPS) constituted by a series of unidentifiable small sources clustered in a large area, generating a diffuse contamination. The latter category predominates in European Functional Urban Areas and cannot be managed with the usual remediation techniques such as those conceived for large/medium contaminated sites, mainly because of the difficulty to identify the many different source areas releasing small contaminant mass. Consequently, the usual remediation procedures are not economically sustainable and often fail to provide results in an acceptable time frame. A powerful tool in this context is transport modeling, as it can be used in combination with statistical methods to assess MPS groundwater contamination even in a highly undetermined setting. Due to the uncertainty related to the exact position and intensity of MPS, a numerical model (MODFLOW/MT3DMS) was implemented in a pilot area in the North-Eastern sector of the Milano FUA. Using the inverse calibration code PEST, a model was calibrated representing the diffuse PCE source field (Italian Law limit is within 1.1 mg/l). This was then used as input to a statistical process based on the Null-Space Monte Carlo (NSMC) method, which allows to generate unlimited sets of sources, all respecting the measured concentrations. 99 different realisations were thus obtained, each attributing a contaminant inflow (with varying concentrations) to every cell of the model top layer. The model minimizing the objective function (composed by the diffuse concentration targets in monitoring wells), gives useful information to assess the overall contaminant sources distribution and to identify the probability of each domain sector to contribute to the contaminant mass inflow
Coupled irrigation-system/groundwater flow modelling for groundwater resource assessment in agricultural areas: A case study in northern Italy
No full textWater resources sustainable management will be one of the major issues that need to be attempted globally in the next decades. Especially south of the Alps, climate projections suggest a strong impact on water resources availability and distribution in space and time. Agriculture would be the most sensitive sector to changing water availability: under warmer climate, crops would be more water-demanding to sustain the evapotranspiration during the growing season. The integrated use of ground- and surface water resources will have a key role in mitigating climate change impact. With the final aim of exploring such possibility, an irrigation-system model (IdrAgra) was coupled with a groundwater flow model (MODFLOW2000), applying it to an area including a portion of the Muzza-Bassa Lodigiana irrigation district in Lombardy. Downscaled projected meteorological data (2080-2099) were applied to the coupled model to estimate changes in the resource availability under climate change scenarios. Results would represent the starting point for the implementation of alternative integrated water resource management policies in agricultural environment
FLOW MODELLING OF TICINO-ADDA BASIN FOR PREDICTION OF GROUNDWATER LEVELS IN CLIMATE CHANGE SCENARIOS
No full textUndergoing climate change could affect substantially water resources in a long term period, not only for an overall drop of them, but for a different distribution of their availability during the hydrological season. Particularly irrigation systems could suffer of that problem, since they need water in specified seasons (springsummer) when usually it has a depletion. Storage of groundwater in aquifers in cold and wetter seasons, when cultivations don't need irrigation, could be used in order to soften irrigation systems water deficit in warmer and drier ones. Regional groundwater models have a key role in the management of groundwater resources, not only evaluating resource availability nowadays, but also predicting effects of management measures in different scenarios. The hydrogeological conceptual model of Ticino-Adda groundwater basin (having an extension of about 8000 km2 between Ticino and Adda river) was implemented based on a revision of the previous study on aquifers of the Lombardy region, conducted by ENI and Regione Lombardia. 87 hydrogeological cross-sections were used to build the bottom of the first 3 aquifers of the groundwater basin (Group Aquifer A, B and C) by means of a detailed
database of hydrostratigraphic logs (about 15 thousands in the whole basin) from ARPA Lombardia. The conceptual model was the starting point for the implementation of a basin scale groundwater flow model (MODFLOW), whose steady-state calibration was performed by means of groundwater survey data conducted by Lombardy Region in
May 2014 in 440 observation points in the 3 aquifers examined. Results of the calibration process point out a residual absolute mean scaled on observation range of about 4 %, suggesting a good accuracy. A pilot groundwater flow sub-model of about 255 km2 was then implemented in the north zone of Lodi Provincia, comprising a large part of the Consorzio Muzza Bassa Lodigiana irrigation district, in order to evaluate the quantity of groundwater resource in climate change and current climate scenarios. Using a down-scaled model (Quantile Mapping method) from the Regional Climate Model, predicted temperature and rainfall for the period 2071-2100 was obtained so that a transient model could be built to estimate change in groundwater resource availability. Furthermore, some analysis had made on the possible exploitation of the groundwater resource for the
softening of irrigation deficit in the global warming scenario first implemente
Assessment of aquifers groundwater storage for the mitigation of climate change effects
No full textIn the coming decades, the effects of expected climate change will affect key aspects of our society including quantity and quality of available water resources. It is believed that water resources will play a growing important role in Europe and in particular in the countries south of the Alps, where climate change could hit harder (EEA, 2014). Without appropriate interventions, water will turn from a good hearty undervalued to a scarce and precious resource, whose distribution will be less and less equitable, resulting in growing conflicts for its use. As already recognized by the European directives (2000/60/EC and 2006/118/EC), the theme of quantitative management of water resources is therefore a strategic issue that can allow the reduction of the risks and costs associated with climate change. Integrated management of both surface and groundwater for sustainable use nowadays represents more and more a key concern in environmental policies and water management. The goal of this work is to assess the effects on groundwater storage of a new management of irrigation waters. The highly variable availability of water resources during the hydrological season could be particularly troublesome in the management of irrigation systems, since they need water in seasons (spring-summer) when usually its availability has a depletion. Storage of groundwater in aquifers in colder seasons could be used to soften irrigation systems water deficit in drier ones. Specifically, the practice of "winter irrigation", i.e. the use of the main irrigation channels to recharge aquifers during the colder seasons, could increase water resource availability for irrigation during the drier growing seasons. A pilot groundwater flow transient model (MODFLOW2000, Harbaugh et al., 2000) with a domain of about 255 km2 was implemented in the north zone of Lodi Province, including a large part of the Consorzio Muzza irrigation district. The model was then run to estimate change in groundwater resource availability in two main scenarios: in the first scenario the storage in the shallow aquifer was computed in the colder period (October–March), when irrigation is not occurring; for this case, it was used measured monthly rainfall, average temperature for the period 2004-2013 (representing actual climate conditions) and an estimations of water volume used for irrigation. In the second scenario, an integrated management approach of irrigation and groundwater was tested, adopting "winter irrigation". Both scenarios want to assess if water storage in aquifers in colder periods could represent an additional water volume useful to mitigate possible climate changes effects on crops
Going Beyond Counting First Authors in Author Co-citation Analysis
Full text linkThe present study examines one of the fundamental aspects of author co-citation analysis (ACA) - the way co-citation
counts are defined. Co-citation counting provides the data on which all subsequent statistical analyses and mappings
are based, and we compare ACA results based on two different types of co-citation counting - the traditional type that
only counts the first one among a cited work's authors on the one hand and a non-traditional type that takes into
account the first 5 authors of a cited work on the other hand. Results indicate that the picture produced through this non-traditional author co-citation counting contains more coherent author groups and is therefore considerably clearer. However, this picture represents fewer specialties in the research field being studied than that produced through the traditional first-author co-citation counting when the same number of top-ranked authors is selected and analyzed. Reasons for these effects are discussed
Variations on the Author
Full text link“Variations on the Author” discusses two of Eduardo Coutinho’s recent films (Um Dia na Vida, from 2010, and Últimas Conversas, posthumously released in 2015) and their contribution to the general question of documentary authorship. The director’s filmography is characterized by a consistent yet self-effacing form of authorial self-inscription: Coutinho often features as an interviewer that rather than express opinions propels discourses; an interviewer that is good at listening. This mode of self-inscription characterizes him as an author who is not expressive but who is nonetheless markedly present on the screen. In Um Dia na Vida, however, Coutinho is completely absent form the image, while Últimas Conversas, on the contrary, includes a confessional prologue that moves the director from the margins to the center of his films. This article examines the ways in which these works stand out in the filmography of a director who offers new insights into the notion of cinematic authorship
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