Accommodation of flooding (flexible buildings and infrastructure)

Objective
Adaptation
Sectors
Water
Impacts addressed
Flooding
Organisation
UNEP-DHI Partnership – Centre on Water and Environment
Technology group
Riverine flood protection
CTCN Keyword Matches
Accommodation
Construction
Traditional building materials and design

Description

This technological approach focuses on designing infrastructure that can withstand the impact of flooding events, resulting in minimizing socio-economic damages and effective climate change adaptation. Accommodation techniques include flood resistant designs aimed at keeping floodwater out of the structure completely, and flood resilient designs, aimed at minimizing structure restoration costs and time if it is flooded. These could include both, new designs or retrofitting existing structures.

Flood resistant structures may include houses raised by stilts or compacted soil or sand, or those built in a way that allows them to move with the water level, for example houses constructed on floating pontoons. Flood resilient structures should be built with material that will minimize flood damage, such as solid and non-absorbing material, waterproof coatings, closed-cell insulation and elevated electricity sockets. Other examples include shutter systems and permanently moored houseboats.

Implementation

Designing for acceptable flood risk levels relies heavily on historic data of flooding events, as well as future climate and local hydrology scenarios. The results amount to flood risk assessments for the region, particularly for the infrastructure in question. Meteorological and flood event data should thus be gathered as part of the initial risks assessment. Planning must also involve all major stakeholders, including local authorities, disaster management team leaders, disaster relief organizations, engineers (if required), scientists, local volunteer groups, etc. This holistic approach ensures acceptable flood levels for vulnerable stakeholders is addressed and ensures compliance with existing legislation and construction requirements. For example, adaptive infrastructure may conflict with national building legislation. In this case, meetings with policy makers may be required, in addition enactment of new regulations. Planning should also be coordinated with early warning systems, safe escape routes and other emergency responses.

Environmental Benefits

- Avoids construction or expansion of structural barriers that may interrupt ecosystems, such as dikes.

Socioeconomic Benefits

- Increases structure resilience and/or resistance to flooding, reducing negative impacts on the buildings, humans and the economic activities.

- Minimizes disruption of socioeconomic activity during flooding events, and reduces costs and time for post flood reconstruction.

- Incorporates climate change adaptation responses into the local planning agenda.

Opportunities and Barriers

Opportunities:

  • Accommodation measures can be implemented at various levels, from regional to community to household
  • Enables further use and development of flood-prone areas
  • It can be a relatively low cost technology, particularly if incorporated in the initial infrastructure design

Barriers:

  • Construction may require changes to existing regulations and building codes
  • Food protection of existing infrastructure may be limited, especially in high risk areas (often more efficient if incorporated in early design)
  • Flood resilient structures may still become flooded, raising the need for temporary accommodation during flood events, and thus requiring additional response resources
  • Efficient and advanced and  flood resistant structures may require more complex expertise and resources, which can make accommodation  a less feasible solution for large scale projects in developing countries

Implementation considerations*



Technological maturity:               1-4 (some technologies are more tested than others e.g. raised houses)

Initial investment:                        2-4

Operational costs:                       1-3

Implementation timeframe:         2-4

 

* This adaptation technology brief includes a general assessment of four dimensions relating to implementation of the technology. It represents an indicative assessment scale of 1-5 as follows:

Technological maturity: 1 - in early stages of research and development, to 5 – fully mature and widely used

Initial investment: 1 – very low cost, to 5 – very high cost investment needed to implement technology

Operational costs: 1 – very low/no cost, to 5 – very high costs of operation and maintenance

Implementation timeframe: 1 – very quick to implement and reach desired capacity, to 5 – significant time investments needed to establish and/or reach full capacity

This assessment is to be used as an indication only and is to be seen as relative to the other technologies included in this guide. More specific costs and timelines are to be identified as relevant for the specific technology and geography.

Sources and further information