Efficiency Assessment of Existing Pumping/Hydraulic Network Systems to Mitigate Flooding in Low-Lying Coastal Regions under Different Scenarios of Sea Level Rise: The Mazzocchio Area Study Case

Abstract

Abstract:Rising of the sea level and/or heavy rainfall intensification significantly enhance the risk of flooding in low-lying coastal reclamation areas. Therefore, there is a necessity to assess whether channel hydraulic networks and pumping systems are still efficient and reliable in managing risks of flooding in such areas in the future. This study addresses these issues for the pumping system of the Mazzocchio area, which is the most depressed area within the Pontina plain, a large reclamation region in the south of Lazio (Italy). For this area, in order to assess climate change impact, a novel methodological approach is proposed, based on the development of a simulation-optimization model, which combines a multiobjective evolutionary algorithm and a hydraulic model. For assigned extreme rainfall events and sea levels, the model calculates sets of Pareto optimal solutions which are obtained by defining two optimality criteria: (a) to minimize the flooding surface in the considered area; (b) to minimize the pumping power necessary to mitigate the flooding. The application shows that the carrying capacity of the hydraulic network downstream of the pumping system is insufficient to cope with future sea level rise and intensification of rainfall.

A Flood Risk Management Model to Identify Optimal Defence Policies in Coastal Areas Considering Uncertainties in Climate Projections

“…Using the 10 years long hourly rainfall time series, and applying the method developed by [65], synthetic hyetographs were generated which distribute the total rainfall amount in 24 h according to a statistical distribution obtained from the hourly rainfall data. In fact, a previous study [45] has shown that 24-h-long heavy rainfall (with a daily rainfall amount greater than 100 mm) has, in the past, induced serious flooding in the examined site. Ref.…”

“…On contrary the flow rates lifted by Mazzocchio pumping station affects the flow characteristics of the downstream area. A previous study by [45] showed, that during heavy precipitation events, higher pumping flow rates reduce the extension of flooding areas upstream from Mazzocchio pumping station, but it worsens the flooding of those downstream. In the current study case, we explore how to increase the resilience to sea level rise of the drainage network downstream from Mazzoccio pumping station, through both the raising of the embankment elevation along the most vulnerable part of the drainage network and the construction of flood expansion areas ruled by weirs along the channels.…”

“…One of the advantages of using HEC-RAS is the possibility to simulate the presence of gates, pumping stations, and other hydraulic devices for flow maneuver. For very large domains, the 2D HEC-RAS code can be coupled with HEC-HMS which is a physically based and conceptually semi-distributed model designed to simulate rainfall-runoff processes to provide flood hydrographs generated externally from the 2D integration domain.The fast simplified hydraulic model [45] models the hydraulic network and the flooplain using three elements: the main river hydraulic networks, the storage areas representing the basins, and the ideal channels connecting the storage areas to points of the rivers belonging to the hydraulic network. The 1D Saint-Venant equations are used to simulate the flow along the rivers which belong to the hydraulic networks.…”

Coastal Vulnerability and Mitigation Strategies: From Monitoring to Applied Research

“…Cioffi et al [31] developed a methodological modeling approach to assess the reliability of hydraulic infrastructures in controlling risks of flooding in a lagoon area in the south of Italy. This zone has an elevation equal to or lower than the mean sea level.…”

Economic Impact of Overtopping and Adaptation Measures in Catalan Ports Due to Sea Level Rise

“…In coastal areas, one of the best-known consequences of global warming is the sea level rise (SLR) and its effects on coastal communities [4]. The study of SLR impacts has focused on its effects on beaches [5,6], coastal defense structures [7][8][9], coastal ecosystems [10], coastal areas [11][12][13][14][15][16] including flooding of urban areas [17,18], or coastal energy infrastructure [19].…”