G. Freni

Analysis Of Intermittent Supply Systems InWater Scarcity Conditions And Evaluation Of TheResource Distribution Equity Indices

Generally, urban water distribution shortage situations are solved by introducing discontinuous service and rationing the available water resources. This approach is widely adopted, not only in developing countries but also in developed ones, for solving short term scarcity conditions which can be caused by unpredicted drought periods. Intermittent distribution has the advantage of requiring small financial efforts but it leads to network operating conditions that are very far from the usual design ones. With the aim to analyse and describe the water supply network behaviour in intermittent conditions, a network hydraulic model has been set up in which both user and manager dependent regulation structures have been schematised (pumps, private reservoirs, etc.). The analysis allowed evaluating network performance introducing several control strategies so suggesting operational plans for reducing the impact of water scarcity events on population and improving resources distribution equity. The presented model has been applied to the water distribution network of Palermo (Italy).

Identification of the best flood retrofitting scenario in an urban watershed by means of a Bayesian Decision Network

Urban resilience to floods can be defined as a city’s capacity to avoid damage through the implementation of structural and non-structural measures, to reduce damage in the case of a flood that exceeds a desired threshold, to recover quickly to the same or an equivalent state, and to adapt to an uncertain future. To build flood resilience, planners need to identify and analyse risk, to understand the impacts of flooding, and how they cope with these impacts by means of innovative and adaptable strategies and measures. The number of possible retrofitting scenarios to cope with flooding problems in an urban watershed could be greatly increased by the combination of several stormwater management practices. Therefore, the present study aims to develop an expert system in the form of a Bayesian Decision Network (BDN) able to evaluate the efficiency of some possible urban flood retrofitting scenario by examining all significant water management variables and their inherent uncertainty. The methodology was applied to an urbanized area of the city of Palermo (Italy).

Urban Drainage And Sustainable Cities:How To Achieve Flood Resilient Societies?

This paper tries to describe the main developments of urban flood forecasting and modelling. Currently, several new technologies are available for flood monitoring, modelling and mitigation and several paradigms suggest the adoption of greener approaches to urban storm water management. These tools and new approaches can be easily adaptable to new developments where the entire urban drainage system can be suited to follow a more sustainable way to drain storm water. The challenge for the future is instead aimed to apply this new philosophy to existing urban areas where the application of new tools and technologies requires high costs and such approaches have to be prepared by constructing a flood resilient society by means of education and capillary information.

Assessment of Water Shortage In Urban Areas

Recent history has demonstrated that extreme hydrological events such as floods and droughts can create additional stress on water supplies essential for human and ecosystem health. As stated several times by European Environmental Agency, the prudent and efficient use of water is thus an important issue in Europe and a number of policies and mechanisms have been used or have been formulated to ensure sustainable use of water in the long term. Urban uses are responsible of almost the 17% of the total European fresh water consumption and they are rapidly growing depending on the extension of urban areas and concentration of population in cities. The present chapter will discuss the phases in the development of a drought management plan starting from the estimation of water supplies and demands, the evaluation of drought risk and urban area vulnerability and, finally, planning procedures and possible mitigation measures

Flood frequency analysis for an urban watershed: comparison between several statistical methodologies simulating synthetic rainfall events

To obtain the flooding frequency distribution for an urban watershed, different methods based on simulations of synthetic rainfall events were compared with an empirical analysis of the flooding data and with the results of long-term simulations. A copula-based multivariate statistical analysis of the main hydrological variables was proposed to generate synthetic hyetographs. Two different approaches were adopted to assess a temporal pattern to the synthetic rainfall: one analyses all available historical rainfall patterns, and another adopts the cluster analysis in three different variants to reduce the computational effort of the analysis. n nTo test the methodology reliability, the analysis was carried out for a real urban watershed. To carry out the flooding frequency analysis, all generated synthetic hyetographs were used as input of a dual drainage mathematical model of the analysed drainage system. Results showed that the method based on the analysis of all historical rainfall patterns was efficient in the estimation of flooding frequency, especially for higher return periods and approximately halved the computational costs of ordinary long-term analysis. Regarding clustering approaches, although attractive for their computational efficiency, their adoption must be carefully evaluated because it could neglect relevant information and result in a less accurate flood frequency analysis.

Statistical analysis of the uncertainty related to flood hazard appraisal

The estimation of flood hazard frequency statistics for an urban catchment is of great interest in practice. It provides the evaluation of potential flood risk and related damage and supports decision making for flood risk management. Flood risk is usually defined as function of the probability, that a system deficiency can cause flooding (hazard), and the expected damage, due to the flooding magnitude (damage), taking into account both the exposure and the vulnerability of the goods at risk. The expected flood damage can be evaluated by an a priori estimation of potential damage caused by flooding or by interpolating real damage data. With regard to flood hazard appraisal several procedures propose to identify some hazard indicator (HI) such as flood depth or the combination of flood depth and velocity and to assess the flood hazard corresponding to the analyzed area comparing the HI variables with user-defined threshold values or curves (penalty curves or matrixes). However, flooding data are usually un...