Carmine Covelli

Optimal design of urban drainage networks

In this paper, a general procedure for the optimal design of urban drainage networks is proposed taking into account realistic technical constraints and the management cost of the automatic flushing devices. The procedure, which is based on the utilisation of a standard genetic algorithm, is first tested with reference to a urban drainage network taken from the literature, while a second test case is considered in order to evaluate the impact of different input parameters and constraints on the optimisation problem. In particular, we evaluate: (i) the effect of considering the crown elevation of the network outlet not fixed a priori but variable in a given range; (ii) the effect of imposing that the size of the conduit downstream a node should be not smaller than the sizes of the conduits upstream; and (iii) the effect of modifying input parameters such as the peak wastewater discharge or the management unit costs.

Optimal Design of Rural Drainage Networks

Abstract In this paper, a novel procedure is presented and demonstrated for the optimal design of rural drainage networks, based on the coupling of a genetic algorithm with suitable hydrologic and hydraulic models. The models, which allow the evaluation of water depth and discharge through the network, differ for the levels of simplification introduced into the representation of physical phenomena (rainfall-runoff transformation and flood wave propagation through channels). Their applications are shown and the use of oversimplified approaches is discussed: although very popular in practice, they can adversely affect the characteristics of the optimal network.

Optimal Location and Setting of PRVs in WDS for Leakage Minimization

Water loss is an issue that affect Water Distribution Systems (WDSs) very often, especially when aged and high pressure occurs. Pressure reduction valves (PRVs) can be used as devices to reduce as much as possible the water losses within the network. Indeed, for a given number of PRVs, the daily volume of water lost from the network can be reduced minimizing the pressure through a proper choice of valve positions as well as their settings. In this paper, a methodology for the optimal number, positioning and setting of PRVs is presented. In the proposed methodology, a genetic algorithm is coupled with a physical modelling of leakage from joints and a simplified and yet realistic hydraulic simulation of the WDS. The proposed methodology is demonstrated using two WDSs examples. Comparisons with a more extreme and complicated hydraulic modelling, already proposed by authors in previous work, are also performed in the first case study in order to validate the proposed methodology. These comparisons demonstrate that the methodology proposed in this work performs fairly well when compared to similar approach that uses a more sophisticated hydraulic model. As a consequence, it revealed to be a good tool for the optimal positioning and sizing of PRVs within WDS aimed at reducing the background leakages even when the WDS is characterized by complex geometry and topology.

Enhancing the Efficiency of the Automatic Design of Rural Drainage Networks

AbstractThe discharges flowing through rural drainage networks depend not only on the local climatic and hydrologic characteristics, but also on the geometric characteristics of the channels constituting the network. For this reason, the evaluation of the design discharges should be accomplished during the search of the optimal network. This leads to time-consuming optimization procedures, and it is desirable to devise efficient numerical alternatives. Two novel models, EGA and EGA-f, are proposed in order to increase the numerical efficiency of genetic algorithms (GAs) for the solution of the optimal rural drainage network problem. Both EGA and EGA-f procedures are based on the use of the nodal excavation depths at the channel ends as decision variables. Moreover, the EGA-f procedure improves EGA by freezing temporarily the design discharges during the optimization process in the case where uniform flows through the channels can be assumed. The application of the two models is demonstrated by means of nu...

Novel Numerical Approach for 1D Variable Density Shallow Flows over Uneven Rigid and Erodible Beds

AbstractThe numerical modeling of hyperconcentrated shallow flows is a challenging task because they exhibit special features, such as propagation over dry beds, profound bed elevation modifications owing to erosion or deposition phenomena, and flow discontinuities. In this paper, a novel depth-positivity preserving Harten, Lax, and van Leer—contact (HLLC) Riemann solver is devised in order to approximate the solution of the Riemann problem for the 1D (one-dimensional) hyperconcentrated shallow flows equations over horizontal beds. The solver is used as a building block for the construction of hyperconcentrated shallow flows (HCSF), a well-balanced finite-volume scheme for the solution of the hyperconcentrated shallow flows equations with variable elevation. HCSF is able to handle the case of dry beds, to take into account the variability of the topography also in the presence of bed discontinuities, considering the flow resistance and the mass exchange between the flowing mixture and the mobile bed. The ...

Optimal Positioning and Sizing of Detention Tanks within Urban Drainage Networks

AbstractThe present work describes a procedure for the evaluation of the optimal number, position, configuration, and sizes of detention tanks in urban drainage networks, to decrease the maximum flow depths and velocities for an assigned return period and to comply with the local design requirements. Each candidate solution of the optimization problem is evaluated by means of a semidistributed hydrological model in which the kinematic wave is used as flood routing model, whereas the variational approach is used to evaluate the critical flow characteristics corresponding to a given return period. The procedure, which makes use of a genetic algorithm to search for the optimal solution among the candidates, is applied to a case study drainage network, considering superpipe-based detention tanks as detention systems. The results indicate that these tanks are effective in the rehabilitation of the drainage network and that the cost of this intervention is substantially lower than that corresponding to the upgr...

Innesco del piping nei rilevati arginali.

PIETRO; Passadore, Giulia; Garbin, Silvia; B., Matticchio; F., Visentin; I., Brunet; R., Lago; F., Facco; Botter, Gianluca; Carniello, Luca. ELETTRONICO. (2016), pp. 1119-1122. ((Intervento presentato al convegno Convegno Nazionale di Idraulica e Costruzioni Idrauliche tenutosi a Bologna nel Settembre 2016. Original Citation: Un sistema modellistico integrato per la previsione in tempo reale delle piene del Muson dei Sassi (Pd)La XXXV edizione del Convegno Nazionale di Idraulica e Costruzioni Idrauliche (IDRA16), co-organizzata dal Gruppo Italiano di Idraulica (GII) e dal Dipartimento di Ingegneria Civile, Chimica, Ambientale, e dei Materiali (DICAM) dell’Alma Mater Studiorum - Universita di Bologna, si e svolta a Bologna dal 14 al 16 settembre 2016. Il Convegno Nazionale e tornato pertanto ad affacciarsi all’ombra del “Nettuno”, dopo l’edizione del 1982 (XVIII edizione). Il titolo della XXXV edizione, “Ambiente, Risorse, Energia: le sfide dell’Ingegneria delle acque in un mondo che cambia”, sottolinea l’importanza e la complessita delle tematiche che rivestono la sfera dello studio e del governo delle risorse idriche. Le sempre piu profonde interconnessioni tra risorse idriche, sviluppo economico e benessere sociale, infatti, spronano sia l’Accademia che l’intera comunita tecnico-scientifica nazionale ed internazionale all’identificazione ed alla messa in atto di strategie di gestione innovative ed ottimali: sfide percepite quanto mai necessarie in un contesto ambientale in continua evoluzione, come quello in cui viviamo. La XXXV edizione del Convegno di Idraulica e Costruzioni Idrauliche, pertanto, si e posta come punto d’incontro della comunita tecnico-scientifica italiana per la discussione a tutto tondo di tali problematiche, offrendo un programma scientifico particolarmente ricco e articolato, che ha coperto tutti gli ambiti riconducibili all’Ingegneria delle Acque. L’apertura dei lavori del Convegno si e svolta nella storica cornice della Chiesa di Santa Cristina, uno dei luoghi piu caratteristici e belli della citta ed oggi luogo privilegiato per l’ascolto della musica classica, mentre le attivita di presentazione e discussione scientifica si sono svolte principalmente presso la sede della Scuola di Ingegneria e Architettura dell’Universita di Bologna sita in Via Terracini. Il presente volume digitale ad accesso libero (licenza Creative Commons 4.0) raccoglie le memorie brevi pervenute al Comitato Scientifico di IDRA16 ed accettate per la presentazione al convegno a valle di un processo di revisione tra pari. Il volume articola dette memorie in sette macro-tematiche, che costituiscono i capitoli del volume stesso: I. meccanica dei fluidi; II. ambiente marittimo e costiero; III. criteri, metodi e modelli per l’analisi dei processi idrologici e la gestione delle acque; IV. gestione e tutela dei corpi idrici e degli ecosistemi; V. valutazione e mitigazione del rischio idrologico e idraulico; VI. dinamiche acqua-societa: sviluppo sostenibile e gestione del territorio; VII. monitoraggio, open-data e software libero. Ciascuna macro-tematica raggruppa piu sessioni specialistiche autonome sviluppatesi in parallelo durante le giornate del Convegno, i cui titoli vengono richiamati all’interno del presente volume. La vastita e la diversita delle tematiche affrontate, che ben rappresentano la complessita delle numerose sfide dell’Ingegneria delle Acque, appaiono evidenti dalla consultazione dell’insieme di memorie brevi presentate. La convinta partecipazione della Comunita Scientifica Italiana e dimostrata dalle oltre 350 memorie brevi, distribuite in maniera pressoche uniforme tra le sette macro-tematiche di riferimento. Dette memorie sono sommari estesi di lunghezza variabile redatti in lingua italiana, o inglese. In particolare, la possibilita di stesura in inglese e stata concessa con l’auspicio di portare la visibilita del lavoro presentato ad un livello sovranazionale, grazie alla pubblicazione open access del volume degli Atti del Convegno. Il volume si divide in tre parti: la parte iniziale e dedicata alla presentazione del volume ed all’indice generale dei contributi divisi per macro-tematiche; la parte centrale raccoglie le memorie brevi; la terza parte riporta l’indice analitico degli Autori, che chiude il volume.