1,720,979 research outputs found
Transmission losses through effluent-fed ephemeral streams: a case study from the Canale Reale River (Brindisi)”
Full text linkClimate change and anthropogenic pressures are the main drivers affecting the sustainability of freshwater resources, worldwide, in term of hydrological cycle.
Rising in temperature and droughts events, have a deep negative impact on the amount of water infiltration and hence groundwater recharge; moreover, the reduction in precipitation forecasted by climate-change models will intensify this process, leading furthermore to a dramatic shift from hydrological perennial regimes to ephemeral. Population growth imposes an additional stress on water resources, especially groundwater, often overexploited for irrigation purposes, meanwhile urbanization processes move together with the tendency to produce waste and therefore the need to build-up new wastewater treatment plants. In many urban environments, discharging treated wastewater from wastewater treatment plants into surface water bodies represents a water resource and ecosystem services management tool to tackle different environmental issues. Although this practice may raise some concerns among people but also scientific community, about possible sanitary and ecological side-effects, as well as the impairment of water quality of receiving streams, the reuse of treated effluent is crucial to support ecosystem quality and urban amenities, to contribute to the environmental baseflow of ephemeral streams and to enhance groundwater recharge processes, especially in semi-arid and arid regions. In arid environments these effluent fed streams are likely to become crucial for guaranteeing a vital equilibrium in the hydrological cycle since aquifer recharge through ephemeral streambeds is believed to be a major source of groundwater storage and replenishment. Groundwater recharge processes are enhanced by transmission losses that preferentially occur trough losing reaches along the streambed, which create a connection between the river and the underling aquifer. Interactions between surface and ground water bodies are extremely complex since several factors may affect the infiltration rate, such as spatial distribution of streambed sediments and hydraulic properties. Owing to the peculiar nature of ephemeral rivers, they often flow within ungauged basin, leading to a significant lack of in situ hydrological data, such as precipitation, streamflow, and evaporation time series.
Furthermore, not all the methods proposed in the scientific literature for estimating
transmission losses in perennial streams can be applied to ephemeral ones, although they can provide some proxy for measuring groundwater recharge from hydraulically connected surface water bodies. The study case is the ideal framework in which all these natural features and hydrological issues converge. The Canale Reale River is an effluent-fed river located nearby the city of Brindisi, on the south-eastern side of the Apulia Region, in Italy. Four wastewater treatment plants discharge within the river a wastewater volume which contributes for about 16.5% of the annual volume of channel drainage (i.e., 3.82 Mm3 out of 23.02 Mm3 distributed along its path, about 50 km) and that partially feeds the Torre Guaceto protected wetland, along the Adriatic coast. Within a complex geological setting, the Canale Reale River flows throughout different lithologies, which reflect in different streambed hydraulic conductivity values. The aim of the study was to investigate the transmission losses occurring between the ephemeral watercourse and the underlying aquifers and to estimate the volume infiltrating which in this specific study case identify with treated wastewater discharge.
By adopting the Reach Length Water Balance method, the estimation of a spatially average value of the riverbed’s infiltration rate applicable to the whole river course was investigated, as well as Potential Transmission Losses (TLP) from the river to the underlying groundwater systems. Combining the estimated TLP values and the Flow Duration Curve (FDC), it was possible to draw the Transmission Loss Duration Curves (TLDCs) and finally, to estimate the water volume infiltrating during an average hydrological year, equal to 6.25 Mm3, 61% of which consist in treated wastewater. The obtained outcomes confirm that the practice of increasing the river flow rates with effluents can be considered a sustainable management tool for both surface and groundwater resources, since in the first case, this allow to reduce the riverbed periods of zero-flow, with potential improvements to the river's ecological sustainability and in the second case, relevant increasing of groundwater recharge is possible
System dynamic approach to evaluate socio-economic-environmental factors influencing sustainability of water use in agricultural production
Full text linkSebbene l’agricoltura irrigua sia ritenuta una delle principali fonti di sfrutta-mento di entrambi le risorse idriche ed energetiche, è’ ampiamente accettato che es-sa svolge un ruolo fondamentale per lo sviluppo socio-economico di molti paesi dell' area mediterranea. Data la sua importanza, in un contesto in cui le risorse idriche sono sempre più soggette a pressioni crescenti a causa delle diverse sfide globali (ad esempio, il cambiamento climatico, la crescita demografica e lo sviluppo eco-nomico), vi è urgente necessità di gestire in maniera sostenibile le risorse idriche destinate a scopi irrigui al fine di garantire elevate rese produttive. Tuttavia, le dinamiche complesse che si instaurano all’interno di un sistema di gestione idrica ad uso irriguo rendono la gestione sostenibile delle risorse idriche di difficile attuazione. Tali sistemi, infatti, sono caratterizzati da un elevata complessità dovuta al compor-tamento di numerosi attori da cui l’utilizzo di risorse naturali dipende e che influisce sulla dinamica del sistema stesso. Non basta, dunque, guardare solo agli aspetti quantitativi dell’utilizzo di risorse idriche (e.g., impatti ammbientali), ma, al fine di supportare la loro gestione sostenibile, è indispensabile anche un’attenta conoscen-za del sistema e della sua dinamica. Da qui deriva, la necessità di affrontare le prob-lematiche della gestione delle risorse idriche in maiera olistica mediante approcci in-tegrati e multidisciplinari.
Tra gli emergenti approcci integrati e multidisciplinari, in ambito scientifico si è af-fermato recentemente il paradigma del nesso tra Acqua-Energia-Cibo, che si configu-ra come un adeguata metodologia capace di supportare la gestione sostenibile delle risorse idriche attraverso l’analisi dei complessi legami tra le risorse naturali inte-grando gli aspetti gestionali della risorsa su scala intersettoriale.
Partendo da queste premesse, al fine di affrontare olisticamente le problematiche del-la gestione sostenibile delle risorse idriche ad uso irriguo, il seguente studio di ricer-ca propone una metodologia innovativa e integrata in grado di operazionalizzare il paradigma di Acqua-Energia-Cibo a scala locale. In particolare la metodologia im-plementata è in grado di valutare le multi-implicazioni dell'uso dell'acqua irrigua at-traverso l'identificazione dei principali fattori che influiscono sul prelievo e lo sfrutta-mento delle risorse idriche. Per cui, al fine di studiare le dinamiche che si instaurano in un sistema di gestione idrica ad uso irriguo, è stato implementato un modello concettuale attraverso l’utilizzo di diagrammi causa-effetto (i.e., Causal loop Dia-grams), considerando un caso di studio rappresentativo situato al Sud Italia nella re-gione Puglia. Tale analisi ha consentito la conoscenza e la definizione dei confini so-ciali ed ambientali del sistema considerato indispenzabile per la definizione degli in-dicatori di sostenibilità rappresentativi della dinamica del sistema. Dunque, tre indici di sostenibilità basati sul concetto di "impronta" sono stati definiti per quantificare l'implicazione multidimensionale della pratica irrigua. In primo luogo, l'Indice di “Im-pronta idrica ad uso irriguo” mira a valutare l'impatto dell'uso dell'acqua irrigua sulle risorse idriche disponibili di una determinata area. In secondo luogo, l'Indice di “Im-pronta Energetica per l’irrigazione” quantifica la quantità di energia consumata per i prelievi e il pompaggio dell'acqua rispetto ai ricavi unitari delle colture. Infine, l'Indice di “Impronta economica” permette la valutazione dei benefici economici della produzione agricola rispetto ai costi dell'acqua utilizzata per l'irrigazione. Tutti gli indi-ci sono stati espressi sia in forma aggregata che separata al fine di valutare gli impatti e i benefici legati all'uso di specifiche fonti idriche quali ad esempio superficiali e sot-terranee.
Infine, l'integrazione degli approcci di cui sopra viene inoltre proposta come ele-mento innovativo del seguente lavoro di ricerca, per supportare la gestione sos-tenibile delle risorse idriche. Difatti, gli indici rappresentano uno strumento im-portante per valutare quantitativamente lo stato dello sfruttamento delle risorse, ma rivelano poco della dinamiche di un dato sistema irriguo, la cui conoscenza è indis-pensabile per valutare l’efficacia dell’implementazione di una data politica di sos-tenibilità.
I risultati ottenuti consentono di trarre alcune conclusioni generali dettagliatamente spiegate nei seguenti capitoli di tesi. In primo luogo, la fitta rete di relazioni tra i di-versi attori decisionali coinvolti influenza fortemente la dinamica del sistema. In se-condo luogo, i comportamenti degli attori sono influenzati sia da fattori esterni (prez-zo di mercato del raccolto e disponibilità idrica) che da vincoli interni (ad esempio, tariffe idriche). Infine, l'efficacia a medio-lungo termine di una determinata politica è influenzata dalla dinamica del Sistema. Pertanto l’integrazione tra aspetti qualitativi della dinamica del sistema con gli aspetti quantitative di utilizzo di risorse idriche si è rivelata di fondamentale importanza per conoscere l'efficacia dell’implementazione di una plausibile politica di sostenibilità nel breve, medio-lungo termine.Irrigated agriculture plays a vital role for socio-economic development of the Mediterranean area, although it is the largest exploiter of both water and energy re-sources. Given its importance, in a context in which water resources experience in-creasing pressure due to different global challenges (i.e., climate change, growth population and economic development among others), there is an urgent need of sustainable management of irrigation water resources. Nevertheless, it is extremely challenging, especially at the local scale, due to several complex and interconnected dynamics establishing in a given irrigation system. In such systems, multiple actors are indeed involved in decision-making processes, and the use of natural resources strongly depends on their behaviors affecting the dynamics of the system itself. As result, facing sustainable management of water resources issues through only a technical knowledge is not enough. Whereas, a careful knowledge of the system and its dynamics is essential for supporting a sustainable management of water re-sources. For the above reasons, integrated approach are needed for dealing with ho-listically water management issues. Among the recent integrated approaches devel-oped in scientific literature the Water-Energy-Food Nexus is surely an useful method-ology for supporting sustainable management of water resources by studying com-plex linkages among resources and integrating management and governance across sector and scale. In order to holistically evaluate sustainable resource management, this study proposes an innovative integrated methodology capable to operationalize the Water Energy Food Nexus (WEFN) at local level evaluating the multi-dimensional implications of irrigation use by identifying the main factors controlling the selection and exploitation of water sources. In detail, a model based on Causal Loop Diagrams (CLD) was implemented in a case study, used as reference, located in Southern Italy in order to get a deeper insight into a complex irrigation system. Moreover, three sustainability indices based on the “footprint” concept were defined in order to quan-tify the multidimensional implication of irrigation practice. Firstly, the Irrigation Water Footprint Index aims to evaluate the impacts of irrigation use on the available water resources of a given area. Secondly, the Energy Footprint for Irrigation Index quanti-fies the amount of energy consumed for water withdrawals and pumping, compared to the unit crop revenue. Finally, the Irrigation Water-Cost Footprint Index supports the evaluation of the economic benefits of agricultural production, compared with the costs of water for irrigation. All indices can be expressed both in an aggregated and disaggregated form to assess the impacts and benefits related to the use of specific water sources. Moreover, the integration of the aforementioned approaches is also proposed as the innovative element for supporting the sustainable management of water resources. Indeed, indices are important instrument to quantitatively evaluate the state of resources exploitation, but they reveal little of a given irrigation system dynamics, which are essential to quantify for identifying the effectiveness of a given sustainability policy. The obtained results reveal some general conclusions. As first finding, a dense network of relationships among different decisional actors involved strongly influence the dynamic of the system. Moreover, it is clear that actor behav-iors is affected by external drivers (i.e., crop market price and water availability) and internal constraints (e.g., water tariff). At the end, the mid-long time effectiveness of a given policy is affected by system dynamic
Analyzing the water-energy-food-ecosystem nexus by integrating hydrological modeling and system dynamics tools
Full text linkEffective and integrated management of natural resources is crucial for achieving sustainability, particularly in the context of interrelated challenges posed by using these resources. This study addresses four complementary as-pects of resource management using a ‘Nexus’ approach within the Tarquinia/ Marta River, highlighting how this region serves as a model that could be ap-plied to other areas of the Mediterranean. The study proposes an innovative approach based on System Dynamics Modeling techniques and hydrological modeling, which is summarized below.
The first chapter emphasizes the Nexus concept, which has gained inter-est as a theoretical framework for understanding the complex interconnections among natural resources. It highlights the need for tools and methods to effec-tively map and analyze these interdependencies, facilitating stakeholder en-gagement in sustainability transitions. In this context, the study employs a Par-ticipatory System Dynamics Modeling (PSDM) approach to enhance the under-standing and management of the Water-Energy-Food-Ecosystem Nexus (WEFE Nexus). This approach is tested concerning the Tarquinia plain in Italy, where a strong interdependency and conflict exists between agriculture and environ-mental conditions. The approach aims to achieve stakeholder consensus on challenges arising from conflicts between different sectors and subsectors in areas under intensive agricultural activity, while also considering future chang-es due to climate change. The analysis of the Causal Loop Diagram (CLD) helps identify the main challenges for the area and highlights the need for a better understanding and modeling of key phenomena. The centrality of agricultural activities, in terms of productivity, relevance for farmers, and impacts on water quality and natural areas, underscores the necessity of investigating these im-pacts and potential mitigation measures using specific agro-hydrological mod-els.
The second chapter builds on the main challenges identified using PSDM and proposes well-established hydrological modeling (SWAT) to further en-hance the understanding and management of the WEFE Nexus. In line with the research objectives, the SWAT model has been utilized with the available da-tasets to first establish the current conditions in the watershed and, secondly, to develop specific scenarios representing the effects of climate change. The Sequential Uncertainty Fitting algorithm version 2 (SUFI-2), a part of the SWAT-CUP tool package, has been employed for calibration, validation, and sensitivity analysis. Data from the EURO-CORDEX initiative includes various climate models involving regional climate models (RCMs) nested in different global circulation models (GCMs) used in this study. Historical experiments and future projections (based on the RCP 8.5 worst-case greenhouse gas emission scenario) have been selected. The most reliable EURO-CORDEX climate projec-tions have been selected following a rigorous performance evaluation of sever-al high-resolution combinations (GCMs-RCMs) over the area. This section of the study has investigated the hydrological balance, soil erosion and nutrient yield in the study watershed, focusing particularly on agricultural practices and cli-mate change impacts. The study findings have revealed significant soil loss and changes in total nitrogen (TN) and total phosphorus (TP) yield under both cur-rent and future scenarios, with agricultural practices exacerbating these issues. Conclusively, this chapter highlights the need for the implementation of effec-tive management strategies and mitigation measures to address these chal-lenges.
The third chapter explores the implementation of Best Management Practices (BMPs) to address on- and off-site impacts resulting from soil erosion and nutrient pollution in the study area, a region susceptible to these environ-mental challenges due to its Mediterranean climate and intensive agricultural practices. Utilizing the Soil and Water Assessment Tool (SWAT), the study as-sesses different individual BMPs, such as terracing, contour farming, no-tillage, and residue management as well as their combination. The results underscore the effectiveness of combined BMPs in reducing erosion and nutrient pollution, with terracing being particularly impactful in minimizing soil loss in hotspot ar-eas within the watershed and reducing sediment and nutrient loading into the river. The analysis emphasizes the importance of integrated BMP approaches for sustainable soil and water management in agricultural areas as well as highlighting the need for targeted management strategies to mitigate envi-ronmental impacts and enhance water quality.
The last chapter focuses on the application of PSDM, describing how a transition from Causal Loop Diagrams to quantitative models (stock and flow) can help explore potential future trajectories of the system under various condi-tions, particularly aiming to enhance its resilience. Stakeholders, including poli-cy and decision-makers, were actively involved in co-designing, analyzing, and discussing relevant scenarios. The study emphasizes the integration of stake-holder knowledge with technical modeling efforts to identify sustainable man-agement strategies for water resources, ecosystems, and agricultural practices in the region. At the core of the chapter is the development of a comprehensive stock and flow model, coupled with the SWAT hydrological model, to investi-gate the long-term impacts of agricultural practices on water resources and ecosystem sustainability. This integrated modeling approach enables a detailed analysis of how management strategies, particularly those involving Nature-Based Solutions (NBS) affect water quantity, quality, and agricultural productiv-ity under varying climate change scenarios. Besides supporting system under-standing, the proposed approach showed the potential to foster stakeholder di-alogue, which is crucial for building consensus on sustainable development pathways for the area. Key methodological challenges and potential needs for further innovation are also included
Influences of Leaf Area Index estimations on the soil water balance predictions in Mediterranean regions
No full text
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
Appropriate Similarity Measures for Author Cocitation Analysis
Full text linkWe provide a number of new insights into the methodological discussion about author cocitation analysis. We first argue that the use of the Pearson correlation for measuring the similarity between authors’ cocitation profiles is not very satisfactory. We then discuss what kind of similarity measures may be used as an alternative to the Pearson correlation. We consider three similarity measures in particular. One is the well-known cosine. The other two similarity measures have not been used before in the bibliometric literature. Finally, we show by means of an example that our findings have a high practical relevance.information science;Pearson correlation;cosine;similarity measure;author cocitation analysis
- …
