Disaster Risk Reduction

Abstract

Urbanization, developmental activities, and climate change have increased the risks of flooding in many areas all around the world. Climate change poses conceptual challenges to managing the water-related disasters. As such, different approaches need to be developed for managing the related risks. This chapter aims to review the evolving policies of disaster risk reduction (DRR) that integrate with climate change adaptation. The stationarity of the hydrometeorological phenomena cannot be applied directly to plan the water-related disaster risk management. The conventional engineering solutions such as construction of structural measures like dams and dykes alone fail to manage the disasters. Countries like the UK, the Netherlands, and Japan have initiated a multilayer approach, in addition to these structural measures, which includes regulating land use, retarding floodwater in floodplains or urban areas, and warning and evacuation systems. Financial arrangement is a crucial element in promoting DRR. Developing countries in Asia require an investment of nearly USD 100 billion or 0.36% of GDP per year as protection against floods. Governments can secure these investments by committing to long-term DRR plans by incorporating DRR into national developmental plans. In addition, they can mobilize the financial sources of official development assistance and climate change financing. Moreover, governments need to attract investments from private sector. Implementation of multilayer measures will need collaborations from a wide range of organizations and stakeholders in order to strengthen the risk governance mechanisms. There is no one-fits-all model of risk governance, but practices show that leadership, learning, and resources contribute to collaborations.

Appendix

Case Study 1: Tsurumigawa River Basin, Japan

This study reviews the Japanese experience and lessons on managing urban flood risks. The Tsurumigawa River basin is located in the Greater Tokyo area and has been experiencing serious flood damage due to rapid urbanization since the 1960s. Semi-structured interviews with key stakeholders and academic experts were conducted in 2017. Project documents and reports were reviewed as well.

Establishing a collaborative mechanism among the national government, local governments, academia, and local communities is crucial to take the integrated approach of FRM. The committee for the Tsurumigawa River basin was established in 1976 to plan the FRM. The committee was chaired by a leading professor of water resource management and consisted of various officers from local and national governments. The committee did not enforce organizations to take specific actions. Instead, each organization was expected to voluntarily implement countermeasures discussed at the committee. The river office of the Ministry of Construction shared disaster information and proposed practical countermeasures.

The committee recommended the following multilayer approach:

• (i) River basin level: (a) to strengthen coordination among concerned organizations, (b) to share disaster information, and (c) to raise public awareness.

• (ii) Hill areas: (a) to regulate and coordinate the development and (b) to formulate technical standards for regulation.

• (iii) Low-lying areas: to regulate landfills and dumping.

Flood damage drastically decreased because of these collaborative efforts. The total number of houses inundated reduced from 10,000 in 1960s to less than 100 in early 2000s (Fig. A1). This happened mainly because key stakeholders shared concern over increasing flood risks because of rapid urbanization and conducted countermeasures in a collaborative way (Fig. A2). The river office of the national government implemented the river works of widening and deepening the channels. City governments regulated developmental activities and instructed residential developer companies to construct retarding ponds to compensate for flood volumes increased by their activities. Moreover, city governments constructed retarding ponds in public areas, such as school playgrounds and sports facilities. A total of 4700 ponds with volumes over three million m³ have now been constructed in the entire river basin. Academic experts facilitated discussions and endosed countermeasures based on their scientific and engineering knowledge. Local communities too engaged in disaster management.

Fig. A1

Number of houses inundated by floods in Tsurumigawa River Basin, Japan

Fig. A2

Collaborative mechanism in Tsurumigawa River Basin, Japan

This initiative was led by the river office of the construction ministry. There are several reasons as to why the office succeeded in involving a wide range of stakeholders. The main reason being the office was in a respectable position to contact local communities, local government offices, and civil society organizations on the ground. The staff of the office understood the needs of local communities and created mutual trust with local communities and local government offices. Last but not the least, government engineers had a high sense of ethics and responsibility toward the public. Thus, they could effectively promote this approach based on trust with the key stakeholders. The office could mobilize academic experts since it had established a long-term relationship by exchanging views on technical issues of the river basin. The personal rotation system of the construction ministry between field offices and the Headquarters contributed to strengthening knowledge management. Staff had obtained knowledge of FRM in an urban area by learning from experiences throughout the country when they worked at the Headquarters. They used that knowledge on the ground at field offices.

Case Study 2: Ormoc City, The Philippines

This study aims to propose the methods of using scientific knowledge for activities in disaster risk reduction (DRR). Developing countries often face difficulties operating and maintaining (O&M) DRR facilities because of limited budget and capacity. The facilities eventually deteriorate, and illegal settlers encroach the facility areas. The study examines how a scheme of scientific knowledge-based decision-making was established for managing flood protection facilities in Ormoc City, the Philippines (Fig. A3).

Fig. A3

Improved channels in Ormoc City, Philippines

Ormoc City, on Leyte Island, survived Typhoon Uring in 1991, leaving nearly 8000 people either dead or missing because of floods. The Department of Public Works and Highway (DPWH) and the city government jointly implemented the flood protection project for improving river channels, constructing sabo-slit dams, and reconstructing bridges with the support of the Japanese government. The sabo-slit dams, widely constructed in Japan to control debris flows, are concrete dam structures with deep narrow slits. In normal times, this dam can flow water through the slits to preserve the environment downstream. In November 2016, semi-structured interviews of the city government staff, DPWH, Japanese aid agency, and experts involved in the project were conducted. Project documents and studies were also reviewed.

The flood protection facilities were properly operated and maintained by ensuring easy flow of scientific knowledge to O&M activities on the ground. The city government and the local office of the DPWH jointly established the flood mitigation committee to promote the activities. In particular, the committee aimed to control the encroachment in river areas to avoid repeating the same scale of flood disasters. Around 3000 victims of the 1991 flood were illegal settlers who lived inside the river areas. The engineers of DPWH and the city government explained the importance of O&M, along with scientific data, at the committee meetings to the leaders of local communities residing along the river and requested them to monitor facility status and encroachment activities. Community leaders head the lowest layer of the government administration system and were in suitable positions to conduct DRR activities on the ground. The city government had allocated annual O&M budgets. The engineers conveyed the engineering information and explained the necessity of the budgets to the Mayor and city council members. Based on the committee’s recommendation, the city government removed buildings illegally constructed inside rivers and conducted O&M activities such as cleaning programs, painting facilities, and cutting grasses.