1,720,961 research outputs found
Multivariate analysis of pressures and driving factors affecting the environmental status of the Rio De Janeiro coastal zone
No full textCoastal areas of the State of Rio de Janeiro represent a wealth of natural resources and are rich of biodiversity, habitat types and nutrients. The same areas also support several human and economic activities. Environmental policies in these areas need to address a multitude of management and environmental impact issues. In such a complexity a multivariate classification of the driving factors and pressures controlling the environmental status of the system may help to support management decisions and to identify action priorities and future environmental concerns
Disentangling the multiple stressors acting on stream ecosystems to support restoration priorities
No full textStream ecosystems may suffer from the effects of multiple stressors. Planning restoration actions without knowing the relative weight of each stressor might lead to disproportionately costly or ecologically meaningless measures. This is particularly relevant under the EU Water Framework Directive (WFD) where economic considerations play a role to justify exemptions from the overarching aim of the Directive of achieving the good ecological status in all the EU water bodies by 2015. In this study we correlated the status of macroinvertebrate assemblages with many environmental variables at 120 monitoring stations (surveyed in 2009-2011) in the streams of Lombardy, Italy. We used a combination of regression techniques to disentangle the effects of the different stressors. Furthermore, different profiles of ecological quality were associated to the dominant stressors. Finally, examples are given about how this study findings provide elements to identify restoration scenarios that maximize the effectiveness/cost ratio
Searching for a compromise between ecological quality targets, and social and ecosystem costs for heavily modified water bodies (HMWBs): The Lambro-Seveso-Olona system case study
No full textThe Lambro-Seveso-Olona (L-S-O) system derives from the human regulation of the natural hydrology
of the territory around Milan city area. The average population density in the L-S-O area is among the
highest in Italy and Europe. Industry is also highly developed in this basin: chemical, textile, paper,
pulp and food industries being the most important ones. Although, at present, the L-S-O system no
longer receives the untreated wastewaters of the Milan urban area, treated wastewaters constitute
about half of the streamflow. Biotic communities in this river have a long history of poor quality
status, having suffered great damage due to domestic and industrial discharges. Recently, new
chemical quality standards for macropollutants have been set by the Italian legislation as support for
the good ecological status according to the Water Framework Directive (WFD). This new index is very
restrictive, and it makes it extremely challenging to achieve the water quality objectives for the L-S-O
system. The aim of this study is to analyse through a modelling exercise the restoration possibilities
of the L-S-O system, investigating both the source apportionment of the macropollutants, the
discharge limits that should be set to achieve the good quality status and their corresponding cost
Managing the nutrient loads of the Venice Lagoon Watershed: Are the loads external to the watershed relevant under the WFD River Basin District framework?
No full textWater policy in the EU needs to be increasingly coordinated under the integrated management structure required by
Water Framework Directive. In the WFD framework, all river catchments are assigned to administrative River Basin
Districts (RBDs) that produce river basin management plans (RBMPs). RBMPs need to define appropriate Program of
Measures (PoMs) based on the knowledge of the pressures and impacts affecting the water environments. However,
pressures may also be external to the administrative RBDs, and still play a significant role. This study presents the case
of the Venice Lagoon Watershed (VLW) and analyses the apportionment of the nutrient loads discharged to the lagoon
by apportioning the external and the internal nutrient sources. VLW is included in the River Basin District of the
Eastern Alps, although due to the complex framework of legislations and authorities that have managed the watershed
to date, it is the object of a separate planning. The source apportionment assessment is assessed at the watershed scale
by combining direct measurements and modeling results. The US Soil and Water Assessment Tool is used to simulate
the expected improvements due to the application of "within watershed” measures. Model simulations pointed out the
significant contribution of the loads external to the watershed, which seriously affect the effectiveness of the “within watershed” PoMs which are revealed largely ineffective if not coordinated with PoMs of boundary RBDs
SWAT meta-moldeling as support of the agricultural soil management in the Venice Lagoon Watershed
No full textIn the last two decades, numerous models and modeling techniques have been developed to simulate nonpoint source pollution effects. Most models simulate hydrologic, chemical, and physical processes involved in the entrainment and transport of sediment, nutrients, and pesticides. Very often these models require a distributed modeling approach and are limited in scope by the requirement of within element homogeneity and by the need to manipulate extensive data sets. Physically based models are extensively used in this field as a decision support for managing the non point source emissions. Common characteristic of this type of models is a demanding input of several state variables that makes more difficult the calibration and effort-costing in implementing any simulation scenario. In this study the USDA Soil and Water Assessment Tool was used to model the Venice Lagoon Watershed (VLW), Northern Italy. A MultiLayer Perceptron network (MLP) was trained on SWAT simulations and used as meta-model for scenario analysis. The MLP meta-model was successfully trained and showed an overall accuracy higher than 70% both on the training and on the evaluation set, allowing a significant simplification in conducting scenario analysis
Water resources management and cost efficiency analysis of different scenarios
No full textWater resources management is a complex issue since it bears many challenges to be resolved and addressed explicitly. Today, we are more concerned than ever to manage earth’s resources in a sustainable way. Naturally uneven distributed water resources have potential to create stress over water-poor areas in the world, and water scarcity seems to be the biggest fear of human kind nowadays. Water quality, in fact, is as important as water quantity. It is actually the first condition to be realized when dealing with the management of water resources since poor quality conditions of water resources affect ecosystem functioning in the habitats of many aquatic species and their surrounding environments as a chain. Once we cannot reach the good water quality in our water bodies we cannot proceed in any way to utilize continuously this vital resource.
There have always been water laws in order to comply with the necessary water quality criteria. These laws sometimes stressed discharge limits for the receiving water bodies and, sometimes required treatment of pollutants at the source. With the advent of Water Framework Directive in 2000 the necessity of an integrated and co-ordinated approach while managing water resources became inevitable. The co-ordinated approach requires the formation of river basin districts and following management plans for every district. These plans must involve watershed specific measures which must be tailored according to needs of the land and the water bodies. The indispensable step in this procedure is the identification of prevailing stressors in the undertaken area. In other words, right diagnosis is essential for the right treatment. Water Framework Directive adopts a holistic approach towards the sustainable management of all types of inland waters, and coastal waters. The very crucial and important phase of this management cycle is the identification of pressures and stressors that are acting directly or indirectly on the status of water resources and, development of appropriate measures for the purposes of full or partial restoration goals. Development of tools and methods is crucial in order to find out the most effective restoration measure. Especially quantitative computer modelling is one of the most useful tools in terms of projection of future scenarios where the water resources can be maintained in their natural integrity. Scenario analyses provide great help in finding the most cost-effective alternative in proposed restoration proposals.
This doctoral dissertation focuses on water resources management in the perspective of developing tools and methods and, measuring the effectiveness and/or cost-effectiveness of various scenarios in an attempt to support decision making process. The research is organized on a case study basis; each case study represents a different water body in terms of geography and physico-chemical properties. The aim was to analyse and understand underlying factors that are affecting the system’s integrity and propose meaningful set of restoration goals. For this purpose we utilized different quantitative models. First case study is a very particular river system in the northern part of Lombardy region. Lambro-Seveso-Olona river system, well known being the most polluted tributary of Italy’s longest river Po; it was modelled through the USEPA QUAL2Kmodel, allowing to consider various scenarios for improving the quality status of the system and to evaluate them in terms of cost and effectiveness.. Second case concerns the Venice Lagoon and its watershed which were analysed through SWAT (Soil and Water Assessment Tool, USDA Model) and Aquatox (USAEPA model) models. While SWAT enabled to apportion the different sources of nutrient load in the watershed, Aquatox enabled to evaluate the trophic status of the Lagoon taking into account the same loads coming from the watershed. In addition, a meta-model was also developed using a neural network approach on the basis of SWAT outputs. The aim was to develop a neural network capable to provide scenario predictions as accurate as the SWAT model but obtained, in shorter time thanks to both the higher computational efficiency and the quickest scenario implementation. Finally, in the last case study multivariate statistical methods were used in order to disentangle the multiple pressures and stresses, affecting the water resources of whole Lombardy region.Water resources management is a complex issue since it bears many challenges to be resolved and addressed explicitly. Today, we are more concerned than ever to manage earth’s resources in a sustainable way. Naturally uneven distributed water resources have potential to create stress over water-poor areas in the world, and water scarcity seems to be the biggest fear of human kind nowadays. Water quality, in fact, is as important as water quantity. It is actually the first condition to be realized when dealing with the management of water resources since poor quality conditions of water resources affect ecosystem functioning in the habitats of many aquatic species and their surrounding environments as a chain. Once we cannot reach the good water quality in our water bodies we cannot proceed in any way to utilize continuously this vital resource.
There have always been water laws in order to comply with the necessary water quality criteria. These laws sometimes stressed discharge limits for the receiving water bodies and, sometimes required treatment of pollutants at the source. With the advent of Water Framework Directive in 2000 the necessity of an integrated and co-ordinated approach while managing water resources became inevitable. The co-ordinated approach requires the formation of river basin districts and following management plans for every district. These plans must involve watershed specific measures which must be tailored according to needs of the land and the water bodies. The indispensable step in this procedure is the identification of prevailing stressors in the undertaken area. In other words, right diagnosis is essential for the right treatment. Water Framework Directive adopts a holistic approach towards the sustainable management of all types of inland waters, and coastal waters. The very crucial and important phase of this management cycle is the identification of pressures and stressors that are acting directly or indirectly on the status of water resources and, development of appropriate measures for the purposes of full or partial restoration goals. Development of tools and methods is crucial in order to find out the most effective restoration measure. Especially quantitative computer modelling is one of the most useful tools in terms of projection of future scenarios where the water resources can be maintained in their natural integrity. Scenario analyses provide great help in finding the most cost-effective alternative in proposed restoration proposals.
This doctoral dissertation focuses on water resources management in the perspective of developing tools and methods and, measuring the effectiveness and/or cost-effectiveness of various scenarios in an attempt to support decision making process. The research is organized on a case study basis; each case study represents a different water body in terms of geography and physico-chemical properties. The aim was to analyse and understand underlying factors that are affecting the system’s integrity and propose meaningful set of restoration goals. For this purpose we utilized different quantitative models. First case study is a very particular river system in the northern part of Lombardy region. Lambro-Seveso-Olona river system, well known being the most polluted tributary of Italy’s longest river Po; it was modelled through the USEPA QUAL2Kmodel, allowing to consider various scenarios for improving the quality status of the system and to evaluate them in terms of cost and effectiveness.. Second case concerns the Venice Lagoon and its watershed which were analysed through SWAT (Soil and Water Assessment Tool, USDA Model) and Aquatox (USAEPA model) models. While SWAT enabled to apportion the different sources of nutrient load in the watershed, Aquatox enabled to evaluate the trophic status of the Lagoon taking into account the same loads coming from the watershed. In addition, a meta-model was also developed using a neural network approach on the basis of SWAT outputs. The aim was to develop a neural network capable to provide scenario predictions as accurate as the SWAT model but obtained, in shorter time thanks to both the higher computational efficiency and the quickest scenario implementation. Finally, in the last case study multivariate statistical methods were used in order to disentangle the multiple pressures and stresses, affecting the water resources of whole Lombardy region.DIPARTIMENTO DI INGEGNERIA CIVILE E AMBIENTALEEnvironmental technologies29CANZIANI, ROBERTOGUADAGNINI, ALBERT
Scenario analysis as decision support for the potential restoration of the heavily modified water bodies in Lombardy. Case study : Lambro, Seveso and Olona rivers
No full textLAUREA SPECIALISTICAPollution of surface waters and the level of degradation of the water quality is a major concern since polluted water bodies can pose a threat for human health and aquatic organisms, and reduce the well being of people since the gains attained from a water body as a resource also will be affected negatively. Therefore it is a vital issue to find the best promise for the restoration of these highly polluted water bodies. The aim of this study is to contribute decision making process by evaluating different scenario analysis for the restoration activities of a heavily modified water body in Lombardy region –a case study; Lambro, Seveso, Olona system. A two dimensional stream water quality model, QUAL2K, was used in order to make the scenario analysis. In the context of the study two scenario analysis have been done which are called ‘PTUA’ and ‘MBR’. The first scenario includes the upgrade of current WWTPs to better the removal of nutrients and some inorganic solids and, the latter includes installment of MBRs as an advanced wastewater treatment method. The results indicate that the MBR installment gives better results on the abatement of the pollutants, namely BOD, COD, ammonium, nitrate nitrogen and total phosphorus; on the other hand, the upgrade of WWTPs also satisfies the threshold values in most of the river length but at a lower extend. The following economic analysis regarding the costs of two different restoration activities revealed that the MBR installments cost more than the upgrade costs of the WWTPs. The final decision should be made taking into account that the concerned river system is a HMWB, and therefore ‘good ecological potential’ instead of ‘good ecological status’ should be achieved according to WFD in order to avoid disproportionate costs of the restoration activities.Pollution of surface waters and the level of degradation of the water quality is a major concern since polluted water bodies can pose a threat for human health and aquatic organisms, and reduce the well being of people since the gains attained from a water body as a resource also will be affected negatively. Therefore it is a vital issue to find the best promise for the restoration of these highly polluted water bodies. The aim of this study is to contribute decision making process by evaluating different scenario analysis for the restoration activities of a heavily modified water body in Lombardy region –a case study; Lambro, Seveso, Olona system. A two dimensional stream water quality model, QUAL2K, was used in order to make the scenario analysis. In the context of the study two scenario analysis have been done which are called ‘PTUA’ and ‘MBR’. The first scenario includes the upgrade of current WWTPs to better the removal of nutrients and some inorganic solids and, the latter includes installment of MBRs as an advanced wastewater treatment method. The results indicate that the MBR installment gives better results on the abatement of the pollutants, namely BOD, COD, ammonium, nitrate nitrogen and total phosphorus; on the other hand, the upgrade of WWTPs also satisfies the threshold values in most of the river length but at a lower extend. The following economic analysis regarding the costs of two different restoration activities revealed that the MBR installments cost more than the upgrade costs of the WWTPs. The final decision should be made taking into account that the concerned river system is a HMWB, and therefore ‘good ecological potential’ instead of ‘good ecological status’ should be achieved according to WFD in order to avoid disproportionate costs of the restoration activities
SWAT meta-modeling as support of the management scenario analysis in large watersheds
No full textIn the last two decades, numerous models and modeling techniques have been developed to simulate nonpoint source pollution effects. Most models simulate the hydrological, chemical, and physical processes involved in the entrainment and transport of sediment, nutrients, and pesticides. Very often these models require a distributed modeling approach and are limited in scope by the requirement of homogeneity and by the need to manipulate extensive data sets. Physically based models are extensively used in this field as a decision support for managing the nonpoint source emissions. A common characteristic of this type of model is a demanding input of several state variables that makes the calibration and effort-costing in implementing any simulation scenario more difficult. In this study the USDA Soil and Water Assessment Tool (SWAT) was used to model the Venice Lagoon Watershed (VLW), Northern Italy. A Multi-Layer Perceptron (MLP) network was trained on SWAT simulations and used as a meta-model for scenario analysis. The MLP meta-model was successfully trained and showed an overall accuracy higher than 70% both on the training and on the evaluation set, allowing a significant simplification in conducting scenario analysis
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
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