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climate risk

Climate and disaster risk in transport: No data? No problem!

Frederico Pedroso's picture
Development professionals often complain about the absence of good-quality data in disaster-prone areas, which limits their ability to inform projects through quantitative models and detailed analysis.
 
Technological progress, however, is quickly creating new ways for governments and development agencies to overcome data scarcity. In Belize, the World Bank has partnered with the government to develop an innovative approach and inform climate-resilient road investments through the combination of creativity, on-the-ground experience, and strategic data collection.
 
Underdeveloped infrastructure, particularly in the transport sector, is a key constraint to disaster risk mitigation and economic growth in Belize. The road network is particularly vulnerable due to the lack of redundancy and exposure to natural hazards (mostly flooding). In the absence of alternative routes, any weather-related road closure can cut access and severely disrupt economic and social movement.
 
In 2012, the government made climate resilience one of their key policy priorities, and enlisted the World Bank’s help in developing a program to reduce climate vulnerability, with a specific focus on the road network. The institution answered the call and assembled a team of experts that brought a wide range of expertise, along with experience from other climate resilience interventions throughout the Caribbean. The program was supported by Africa, Caribbean and Pacific (ACP) European Union funds, managed by the Global Facility for Disaster Reduction and Recovery (GFDRR).
 
Our strategy to address data scarcity in Belize involves three successive, closely related steps.

The “plastic bridge”: a low-cost, high-impact solution to address climate risk

Oliver Whalley's picture
Also available in: Français
Photo: Anthony Doudt/Flickr
Bridges are critical links in the transport network. In their position across waterways, they are exposed to the full effects of flooding and landslides, and are often the first pieces of infrastructure to be damaged in the event of a disaster. They also typically take weeks or months to repair.  Besides causing expensive damage to the infrastructure itself, disruptions in connectivity also have a much broader impact on economic productivity and people’s ability to access essential services. As many places are expected to witness more intense and frequent rainfall as a result of climate change, the risk to bridges will only worsen: more rainfall will lead to bigger river flows and more damage to bridges, especially those designed to handle smaller storms.

At each end of a bridges is a structure which supports the weight of the deck. These are known as abutments, and they are often the first part of the bridge to fail. Blockage of the main channel by debris can cause water to look for the path of least resistance around the sides of the bridges, thus placing the abutments at risk.

Traditional bridge construction requires the installation of piles for the foundations of abutments—a lengthy and expensive process that involves specialist materials, skills and equipment.

But there is another promising solution: Geosynthetic Reinforced Soil (GRS) abutments. These allow for rapid and resilient construction of bridge abutments using locally available materials, without specialized equipment. With GRS, bridges can be constructed in as little as five days (Von Handorf, 2013) and at a cost 30-50% lower than traditional approaches (Tonkin and Taylor, 2016) .

GRS abutments are based on ‘geogrids,’ a high density mesh made out of polyethylene (plastic). Layers of soil and geogrid are combined to create a solid foundation for the bridge deck. Construction can be completed with basic earthmoving and compaction equipment, and a range of local fill materials can be used with guidance from geotechnical specialists.