1,721,056 research outputs found
Methods for the identification of geostatistical model parameters: a reliability study by numerical analysis
No full textControllo dei livelli freatici mediante un sistema di drenaggio: valutazione di massima della sua efficacia mediante modellazione matematica
No full textRainfall temporal variability and rainwater harvesting efficiency: an analysis over the Italian territory.
Full text linkLa raccolta d’acqua piovana per usi interni è una delle pratiche percorribili per una gestione sostenibile dell'acqua a scala urbana.
La realizzazione di un sistema di raccolta d'acqua piovana dipende strettamente dai costi e dallo spazio richiesto, per cui è necessaria una progettazione accurata, soprattutto in fase di dimensionamento del serbatoio.
Il volume del serbatoio è un elemento importante del sistema, che ha impatti importanti non solo riguardo questioni ambientali come il volume d'acqua potabile risparmiato e la riduzione dei volumi d’acqua piovana inviati alla rete fognaria, ma anche riguardo i costi e la realizzazione pratica del sistema di raccolta.
Tuttavia, mentre il mondo professionale cerca soluzioni facili da applicare (ad esempio metodi di dimensionamento semplificati), da un punto di vista scientifico molti aspetti devono ancora essere implementati. Tra questi aspetti, il presente abstract tratta del ruolo che ha la variabilità temporale delle precipitazioni riguardo il dimensionamento dei serbatoi. La variabilità temporale delle precipitazioni viene misurata tramite il coefficiente di variazione dell'altezza di pioggia, a scala giornaliera. Il metodo di analisi è stato applicato all'intero territorio italiano, utilizzando i dati di precipitazioni osservati contenuti nel database nazionale Scia-Ispra
Stochastic description of infiltration between aquifers
Full text linkAim of this work is to propose a stochastic description of the leakage between two aquifers separated by a semi-permeable layer with low hydraulic conductivity. The source of uncertainty here considered is the random fluctuation of the phreatic surface of surficial aquifer, originated from random rainfall events. The study focuses on an area surrounding a pumping well penetrating the deep aquifer and impacting its piezometric level, where infiltration from the surficial aquifer can be more harmful. Closed form expressions for the leakage between the surficial and the deep aquifer are used to obtain the long-term probability distribution of leakage flow rate, assuming the shallow phreatic surface dynamics modeled with a Poisson- driven stochastic process. A sensitivity analysis is performed to verify the variability of the probability distribution of leakage within the range of feasible parameter values, then the stochastic model is applied to three field cases where time series of the piezometric levels of the phreatic aquifer are available. Results show that the induced variability of the discharge flowing between aquifers is remarkable and that in general it cannot be neglected despite the low hydraulic conductivity of the semi-permeable layer. The proposed probabilistic model is a useful tool for evaluating the risk associated to contaminant transport into deep aquifers and its fate in relation to groundwater withdrawal
Estimation of the hydropower potential of irrigation networks
No full textOver the last decade, the increase in the costs of non-renewable energy sources and a growing environmental awareness have led research institutions and companies to show more interest in renewable energy, and that derived from hydraulic sources has been undergoing a resurgence of interest, especially concerning Small Hydropower Plants. In this context, it could be interesting to consider the role of irrigation networks and set up methodologies to estimate the hydropower potential of canal systems as a preliminary analysis to guide feasibility analysis. This work reviews different methodologies for the computation of the hydropower potential and presents a method that can be used to analyze irrigation networks in order to establish their hydropower production potential. The proposed methodology is simple and it allows: i) an irrigation network to be characterized and networks with higher hydropower potential to be identified, ii) the actual combination between irrigation and hydroelectric usage to be quantified and iii) hydropower development scenarios to be drawn up. The presented methodology can be considered a preliminary analysis tool, although detailed site-specific studies are necessary for feasibility analysis. In order to show an application example, the methodology has here been applied to the Piedmont Region irrigation system, considering data obtained from computerized databases. © 2015 Elsevier Lt
Un' applicazione del Kringing non lineare per la stima delle concentrazioni nelle acque sotterranee
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Water savings and urban storm water management: Evaluation of the potentiality of rainwater harvesting systems from the building to the city scale
Full text linkThe main potential benefits of rainwater harvesting, namely water saving and storm water management, are easily evaluable at a building scale when well-known behavioral models are used. However, the evaluation is often more complex at an urban scale, due to a lack of building characteristics and demographic data. In the present paper, we propose a method, which is based on the representative building concept that can be used to quantify the potential benefits of rainwater harvesting at different scales, that is, from the building scale to the district and city scales. Particular attention has been paid to the sizing of the system so that it can be used for different rainwater collection purposes. The method has been applied to the city of Turin (Italy) considering different scenarios: 1) domestic use (e.g., toilet flushing and the washing machine), where buildings are independent of each other, and 2) two public uses (the irrigation of public green areas and street washing), for which we have hypothesized that the rainwater collection takes place at a district scale. The non-potable water saving for domestic use varies across the city from 29% to 62%, according to the characteristics of the buildings, while the reduction of the flow peak conveyed to the sewerage system, during extreme storms, is quite constant (in the 57–67% range). Irrigation and street washing require a lower amount of water, thus about 80% of water can be saved, but the retention efficiency is low, and a slight reduction in the flow peaks can be expected. The aim of the methodology presented in this work is to provide a suitable decision-making tool for policy makers and urban planners to evaluate the capability and efficiency of rainwater harvesting systems for buildings, districts, and cities
L'approccio geostatistico per la ricostruzione della storia di rilascio di inquinanti in falda
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