Public Participation Approaches in Implementing DRR Measures

Communication to and participation of the public is an important aspect of many planning processes, this also includes the development of DRR plans and strategic alternatives. This description is based on a project handbook that has been especially designed to support regional and local administrations in the planning and implementation of communication and public participation processes in flood prone areas. The findings of this report can also be applied to coastal areas.

Multi-Criteria Analysis (MCA)

The Multi-Criteria Analysis (MCA) is one of the five tools used to assess the proposed measures in each of the RISC-KIT case studies with respect to criteria that capture the key dimensions of the decision-making process. The purpose of the MCA is to bridge the disciplinary divide between engineering sciences and social sciences, facilitate the communication and dissemination of project results to a broad audience, and to integrate scientific knowledge with local knowledge with the purpose of improving the assessment of coastal risks.

Drainage system management

Urban drainage systems need to be able to deal with both wastewater and stormwater whilst minimizing problems to human life and the environment, including flooding. Urbanization has a significant effect on the impact of drainage flows on the environment: for example, where rain falls on impermeable artificial surfaces and is drained by a system of pipes, it passes much more rapidly to the receiving water body than it would have done when the catchment was in a natural state. This causes a more rapid build-up of flows and higher peaks, increasing the risk of flooding (and pollution) in the receiving water. Many urban drainage systems simply move a local flooding problem to another location and may increase the problem. In many developed counties there is a move away from piped systems, towards more natural systems for draining stormwater.

Exposed elements elevation

'Elevation of buildings' and ' Land raising' are two separated measures with the aim to elevate exposed elements.

Exposed element relocation and removal

Moving a building out of the existing flood hazard area is the safest solution among several retrofit-ting methods; however it is also usually the most expensive method (FEMA, 2009). When a community acquires a flood-prone home from the owner, relocation is often applied, as well as demolition of the building. The relocation is not only limited to buildings, it can also be applied to other exposed coastal infrastructure.

Dry proofing - sealing and shielding

Dryproofing makes a building watertight and substantially impermeable to floodwaters (FEMA, 1993). Compared to wetproofing, dryproofing requires a more reinforced building structure to withstand floodwater pressures and impact forces caused by debris. Other important factors to be considered in dryproofing are watertight closures for doors and windows, prevention of floodwater seepage through walls, and check valves to prevent reverse flows from sewage.

Wet proofing - Sealable buildings

Wetproofing (or wet floodproofing) is different from dryproofing in that it allows flood water to enter a structure, though both floodproofing methods have the same purpose, that of preventing damage to the structure and its contents and creating no additional threats to public safety (FEMA, 1993).