**3. Case study area**

*Recent Advances in Flood Risk Management*

ity of natural and socio-economic data is limited.

**2. Proposal of evidence-based flood contingency planning**

employed in the ISO22301, six steps are proposed, as shown in **Figure 1**.

The "ISO22301 Societal security—Business continuity management systems" specifies requirements for all types of organisations to plan, implement, review and improve a documented management system to prepare for, respond to and recover from disruptive incidents [2]. It requires the organisations to select business continuity strategy based on the outputs from the risk assessment and business impact analysis. The risk assessment aims to identify and evaluate the risk of disruptive incidents to the organisations, while the business impact analysis assesses the impacts of disrupting activities that support organisation's services. To conduct evidence-based flood contingency planning in reference to the procedures

The first step of this planning is to understand the current conditions of the target communities such as topography, land use, population and structures, as well as

In order to achieve effective disaster response, it is important first to assume possible disasters, then quantify expected disaster damage and conduct contingency planning based on the scenarios of the possible disasters. One of the practical tools to carry out this process is evidence-based flood contingency planning, which is based on scientific approaches such as flood simulation and quantitative risk assessment. This planning method, however, is not always feasible to disaster-prone areas in Asia due to the lack of data on natural and social conditions. To overcome such a challenge, the International Centre for Water Hazard and Risk Management (ICHARM) focuses on flood disasters and proposes an effective method for local communities to predict the dynamic change of inundation using flood simulation, assess flood risk with key indicators, decide coping strategies against the identified flood risk and develop a contingency plan beforehand. This method is first applied to one of the flood-prone areas in Asia, Calumpit Municipality in the Pampanga River basin of the Philippines, to verify its effectiveness in areas where the availabil-

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**Figure 1.**

*Six steps of evidence-based flood contingency planning.*

Among the Asian flood-prone areas, a municipality called Calumpit was selected as the first case study area. It is in Bulacan Province in Pampanga River basin located northwest of Metro Manila in Central Luzon Island, Philippines. The municipality lies at the junction of several rivers, including Pampanga, Angat and Labangan, as illustrated in **Figures 2** and **3**. This topography makes Calumpit one of the most flood-prone municipalities in the Philippines. As of 2010, 101,068 people live in an area of 5625 ha, or 2.03%, of the province. The municipality has 29 barangays, the smallest administrative units. The recent largest flood was caused by Typhoons

**Figure 2.** *Location of Calumpit in Pampanga River basin. (a) Luzon Island and (b) Pampanga River basin).*

**Figure 3.** *Land use map of Calumpit [4].*

Pedring and Quiel in September 2011, and a large area of the municipality suffered massive flood damage. Due to an inundation of 1.2–1.5 m deep, Calumpit lost its government functions, which consequently impeded emergency response.

The Philippine Disaster Risk Reduction and Management Act (Republic Act No. 10121) [3], enacted in 2010, provides for the development of policies and plans and the implementation of actions and measures related to all aspects of disaster risk reduction and management. It defines the National Disaster Risk Reduction Management Council (NDRRMC) as the national organisation to coordinate, integrate, supervise, monitor and evaluate disaster policymaking. It also mandates the establishment of the Disaster Risk Reduction and Management Office in every barangay, municipality, city and province.

Calumpit has the Municipal Disaster Risk Reduction Management Council (MDRRMC) and the Barangay Disaster Risk Reduction Management Council (BDRRMC) in its 29 barangays. The act defines MDRRMCs and BDRRMCs to perform functions such as designing and coordinating disaster risk reduction and management activities, supporting risk assessments and contingency planning activities at the local level [3]. Following this act, the MDRRMC of Calumpit published a contingency plan [4], which describes governmental emergency response in case of a flood. It assumes casualties, structural damage and impacts on livelihood, infrastructure and facilities in the worst-case scenario, based on the experience during Typhoons Pedring and Quiel in 2011. However, the scenario based on the past flood experiences makes it difficult to assume future floods of different scales which have never occurred before. It is therefore recommended to make contingency plans by quantifying a spatial distribution of expected damage and necessary needs in consideration of dynamic changes in inundation depth provided from flood inundation simulations performed for each community.
