Effectiveness of investing in flood protection in metropolitan areas: lessons from 2019 Typhoon Hagibis in Japan

Purpose This study aims to demonstrate the effectiveness of investment in flood protection by analyzing the flood disaster caused by Typhoon Hagibis in Japan in October 2019. The typhoon severely damaged the central and eastern Japan regions and threatened the Greater Tokyo area. Design/methodology/approach The paper examines flood risks in the Greater Tokyo area and reviews how the flood protection systems functioned to protect Tokyo from the typhoon. The hydrological data of rainfall and water levels at major rivers and the operation records of flood control facilities are collected and analyzed. Findings The study’s major finding is that the flood protection system succeeded in protecting the Greater Tokyo area from flooding. Typhoon Hagibis maintained its power until landing because of climate change and caused record-breaking rainfall. In a worst-case scenario, thousands of people could have died and hundreds of billions USD worth of assets could have been lost in Tokyo. Practical implications The paper describes the actual effects of the flood protection systems, consisting of dams constructed upstream, reservoirs midstream and diversion channels downstream. Thus, this study’s findings directly relate to practical implications for other countries and cities, which face flood risks under a changing climate. Originality/value The paper highlights the importance of investing in flood protection by examining actual disasters and providing detailed descriptions of flood protection systems.

Evaluation of Green and Grey Flood Mitigation Measures in Rural Watersheds

Floods cause considerable damages worldwide and mitigation of their adverse effects through effective protection measures is needed. Along with the commonly applied “grey” infrastructure, “green” measures that can offer additional benefits, such as ecosystem services, are increasingly being considered lately. While the recent research tendencies are focused on the effectiveness and the value of green measures in urban areas, this paper presents a comprehensive financial evaluation of green and grey flood mitigation scenarios for a smaller rural watershed. A micro-scale damage model that builds on the hydrodynamic modeling of hazard, detailed asset identification, and damage assessment is presented and applied for evaluation of benefits from various flood mitigation measures in the Tamnava watershed in Serbia. Four scenarios are considered: (1) existing flood protection system; (2) green scenario involving new detention basins; (3) grey infrastructure enhancement by rising of the existing levees and diverting flood discharges; and (4) green-grey scenario that combines scenarios (2) and (3). The benefits (loss reduction) are the greatest with the green scenario and marginally higher with the combined green-grey scenario. The results suggest that for small rural watersheds, a holistic, integrative approach that includes both types of infrastructure can provide the most effective flood risk mitigation.

Efficiency of Polder Modernization for Flood Protection. Case Study of Golina Polder (Poland)

This paper presents an analysis of the effectiveness of variants of the reconstruction of a polder, which is part of the flood protection system of a large urban agglomeration. The Golina polder, located in the floodplain of the Warta River, was selected as the case study. The multi-criteria decision support methods AHP and Fuzzy AHP were used to assess the effectiveness of individual variants. Information on the floods from 1997 and 2010, data on land cover, land development, nature and historical objects were used to estimate the value of the coefficients for the multi-criteria decision methods. It was shown that the planned deep modernization of the hydrotechnical infrastructure and the purchase of land in the polder area is less effective than maintaining the current state of development of the polder.

The Management Of Flood Protection System Of Dewa Ruci Underpass In Bali

Dewa Ruci intersection is one point of traffic congestion point in Bali. Dewa Ruci is a major intersection that connects the city of Denpasar, Kuta, Jimbaran, and Nusa Dua. In addressing traffic congestion, built underpass so that traffic becomes smooth when passing through the intersection Dewa Ruci. Part of the Dewa Ruci intersection is below the ground level, so risks of flooding. The source of water that potentially fills the underpass is groundwater seepage and rainfall. The flood protection of the underpass is capable of storing 1344 m3 water and with the pumping system. In this research, the maintenance, operation, and management model of the flood protection system is developed that includes the development of organizational structures and standard operating procedures to ensure that the Dewa Ruci flood protection system works well sustainably.

Hibridno napajanje telekomunikacione i merne opreme daljinskih mernih stanica u sistemima zaštite od poplava

The paper will present the implementation of a hybrid power supply for telecommunication and corresponding measuring equipment of remote measuring stations, which are an integral part of the flood protection system. Solar power is the primary energy source during the day, while in night conditions it is actually used as a distribution network (which also supplies street lighting). The power system is implemented with two controlled MPPT chargers (mains and solar), 12V / 110Ah battery bank and associated monitoring system. The paper will present key experimental results obtained during the release of a concrete realized measuring station and associated telecommunication equipment, on the Ub River, Ub Municipality.

Municipality’s financial potencial and policy of flood risk management in Poland

For Polish municipalities – basic units of local government (LGU), flood constitutes a significant source of material losses resulting both from flood damages and from the costs of restoring the regular functioning of the municipalities after the disaster is gone. Authors stated a thesis that the municipality, despite its constitutional obligations connected with providing the safety for its citizens, is not capable to bear the financial burden shaping the flood protection system in the basin. It is, however, due to support the flood protection system by strengthening its adaptive potential and adaptive capacity for efficient limitation of adverse consequences of flood. To justify this thesis, the financial condition of the municipalities threatened with flood was compared to the size of potential flood losses for floods of the medium probability of occurrence (p = 1%). Authors have shown that the municipality’s structure, more than its budget size decides about its financial potential. Especially the municipality’s own revenue is an evidence for the determined financial potential, at the same time, it can be a source of the undertaken actions in order to increase the level of the municipality’s adaptability in the context of flood hazard. Conducted analyses allow to shape the flood risk management policy, both at the municipal level and on a national scale.

Information support systems for cultural heritage protection against flooding

The goal of this paper is to present use of different kind of software applications to create complex support system for protection of cultural heritage against flooding. The project is very complex and it tries to cover the whole area of the problem from prevention to liquidation of aftermath effects. We used GIS for mapping the risk areas, ontology systems for vulnerability assessment application and the BORM method (Business Object Relation Modelling) for flood protection system planning guide. Those modern technologies helped us to gather a lot of information in one place and provide the knowledge to the broad audience.