Dimensionamento di invasi per il controllo dei deflussi nei bacini urbanizzati

Urbanization is a continuing phenomenon in all the world. Grasslands, forests, etc. are being continually changed to residential, commercial and industrial complexes, roads and streets, and so on. One of the side effects of urbanization with which engineers and planners must deal with, is the increase of peak flows and volumes of runoff from rainfall events. As a result, the urban drainage and flood control systems must be designed to accommodate the peak flows from a variety of storms that may occur. Usually the peak flow, after development, is required not to exceed what would have occurred from the same storm under conditions existing prior to development. In order to do this it is necessary to design detention storage to hold back runoff and to release it downstream at controlled rates. In the first part of the work have been developed various simplified formulations that can be adopted for the design of stormwater detention facilities. In order to obtain a simplified hydrograph were adopted two approaches: the kinematic routing technique and the linear reservoir schematization. For the two approaches have been also obtained other two formulations depending if the IDF (intensity-duration-frequency) curve is described with two or three parameters. Other formulations have been developed taking into account if the outlet have a constant discharge or it depends on the water level in the pond. All these formulations can be easily applied when are known the characteristics of the drainage system and maximum discharge that these is in the outlet and has been defined a Return Period which characterize the IDF curve. In this way the volume of the detention pond can be calculated. In the second part of the work have been analyzed the design of detention ponds adopting continuous simulation models. The drainage systems adopted for the simulations, performed with SWMM5, are fictitious systems characterized by different sizes, and different shapes of the catchments and with a rainfall historical time series of 16 years recorded in Bologna. This approach suffers from the fact that continuous record of rainfall is often not available and when it is, the cost of such modelling can be very expensive, and that the majority of design practitioners are not prepared to use continuous long term modelling in the design of stormwater detention facilities. In the third part of the work have been analyzed statistical and stochastic methodologies in order to define the volume of the detention pond. In particular have been adopted the results of the long term simulation, performed with SWMM, to obtain the data to apply statistic and stochastic formulation. All these methodologies have been compared and correction coefficient have been proposed on the basis of the statistic and stochastic form. In this way engineers which have to design a detention pond can apply a simplified procedure appropriately corrected with the proposed coefficient.

Numerical modelling and structural optimization of multifunctional maritime structures aimed to protect harbours and produce energy

The main objective of this PhD thesis is to optimize a specific multifunctional maritime structure for harbour protection and energy production, named Overtopping Breakwater for Energy Conversion (OBREC), developed by the team of the University of Campania. This device is provided with a sloping plate followed by a unique reservoir, which is linked with the machine room (where the energy conversion occurs) by means of a pipe passing through the crown wall, provided with a parapet on top of it. Therefore, the potential energy of the overtopping waves, collected inside the reservoir located above the still water level, is then converted by means of low – head turbines. In order to improve the understanding of the wave – structure interactions with OBREC, several methodologies have been used and combined together: i. analysis of recent experimental campaigns on wave overtopping discharges and pressures at the crown wall on small – scale OBREC cross sections, carried out in other laboratories by the team of the University of Campania; ii. new experiments on cross sections similar to the OBREC device, planned and carried out in the hydraulic lab at the University of Bologna in the framework of this PhD work; iii. numerical modelling with a 1 – phase incompressible fluid model IH – 2VOF, developed by the University of Cantabria, and with a 2 – phase incompressible fluid model OpenFOAM, both available from the literature; iv. numerical modelling with a new 2 – phase compressible fluid model developed in the OpenFOAM environment within this PhD work; v. analysis of the data gained from the monitoring of the OBREC prototype installation.

Governing the water conservation in the Urmia Lake Basin: addressing macro systems’ fit and micro users’ behavior

To change unadapted water governing systems, and water users’ traditional conducts in line with climate change, understanding of systems’ structures and users’ behaviors is necessary. To this aim, comprehensive and pragmatic research was designed and implemented in the Urmia Lake Basin where due to the severe droughts, and human-made influences, especially through the agricultural development, the lake has been shrunken drastically. To analyze the water governance and conservation issues in the basin, an innovative framework was developed based on mathematical physics concepts and pro-environmental behavior theories. Accordingly, in system level (macro/meso), the problem of fit of the early-shaped water governing system associating with the function of “political-security” and “political-economic” factors in the basin was identified through mean-field models. Furthermore, the effect of a “political-environmental” factor, the Urmia Lake Restoration Program (ULRP), on reforming the system structure and hence its fit was assessed. The analysis results revealed that by revising the provincial boundaries (horizontal alternation) for the entity of Kurdistan province to permit that interact with the headquarter of West Azerbaijan province for its water demand-supply initiatives, the system fit can increase. Also, the constitution of the ULRP (vertical arrangement) not only could increase the structural fit of the water governing system to the basin, but also significantly could enhance the system fit through its water-saving policy. Besides, in individual level (micro), the governing factors of water conservation behavior of the major users/farmers were identified through rational and moral socio-psychological models. In rational approach, incorporating PMT and TPB, the SEM results demonstrated that “Perceived Vulnerability”, “Self-Efficacy”, “Response Efficacy”, “Response Cost”, “Subjective Norms” and “Institutional Trust” significantly affect the water-saving intention/behavior. Likewise, NAM based analysis as a moral approach, uncovered the significant effects of “Awareness of Consequences”, “Appraisal of Responsibility”, “Personal Norms” as well as “Place Attachment” and “Emotions” on water-saving intention.