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

Oliver Whalley's picture
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.

Climate change is forcing us to reinvent rural transport for the better

Ashok Kumar's picture
Photo: Ravisankar Pandian/Flickr
India is in the midst of implementing PMGSY, a $35-billion national level Rural Road Program designed to provide basic road access to rural communities. The World Bank is supporting PMGSY through a series of lending operations ($1.8 billion in Bank funding) and significant knowledge support. A key element of the Bank’s support has been to integrate a “climate and green growth lens” into these efforts in cost-effective ways.

How is “green growth” benefiting India? One important dimension of that effort has been  the use of environmentally optimized road designs, which has resulted in quality infrastructure using local and marginal materials, providing both economic and environmental benefits. Where available, sand deposits accumulated from frequent floods, industrial by-products, and certain types of plastic, mining, and construction waste have been used to good effect. Designs that use such materials have been about 25% cheaper to build, on average, than those requiring commonly used rock aggregates. The environmental benefits of using the above materials, in terms of addressing the big disposal problem of such materials and reducing the consumption of scarce natural stone aggregates, are as significant as the cost savings.

A second “green growth” dimension has been focusing investments on the “core” network, i.e. the network India needs to develop in order to provide access to all villages. Relative to a total rural road network of about 3.3 million kilometers, the core network that falls under PMGSY stretches over only 1.1 million kilometers. Prioritizing construction and maintenance on those critical road links will bring down costs as well as the associated carbon footprint.

On the road to resilience: Reducing disaster and climate risk in Africa

Ede Ijjasz-Vasquez's picture
As 60 million people in Africa await humanitarian assistance due to the worst El Nino in decades, the World Bank is actively engaged in 14 countries to plan recovery programs worth more than $500 million. (Photo: Flore de Preneuf / World Bank)


Natural disasters—such as droughts, floods, landslides, and storms—are a regular occurrence, but climate change is increasing the frequency and intensity of such weather-related hazards. Since 1970, Africa has experienced more than 2,000 natural disasters, with just under half taking place in the last decade. During this time, natural disasters have affected over 460 million people and resulted in more than 880,000 casualties. In addition, it is estimated that by 2030, up to 118 million extremely poor people (living below $1.25/day) will be exposed to drought, floods, and extreme heat in Africa. In areas of recurrent disasters, this hampers growth and makes it harder for the poor to escape poverty.

The World Bank has a new Climate Action Plan. What's in it for cities?

Ede Ijjasz-Vasquez's picture
The World Bank Group’s Climate Action Plan, adopted last month, is designed to help countries meet their COP21 pledges and manage increasing climate impacts.
 
To achieve these goals, working with cities will be essential: with almost 80% of GHG emissions emanating from urban areas, cities are among the biggest contributors to climate change... and must, inevitably, become a big part of the solution.
 
Cities are also particularly vulnerable to climate risk and other forms of natural hazards, with many of them located in disaster-prone areas. Therefore, enhancing disaster resilience in urban settings is another key requirement to build more sustainable cities in the face of climate change.
 
The good news? Many countries are still in the early stages of the urbanization process, meaning they have a unique opportunity to develop sustainable cities right from the beginning - a much more viable option than trying to retrofit them later on.
 
In this video, World Bank Senior Director Ede Ijjasz-Vasquez and Practice Manager Bernice Van Bronkhorst explain how they are working with clients to make climate-smart cities a reality.
 
If you want to learn more about this topic, we invite you to discover our latest Sustainable Communities podcast.

Mitigating El Niño's impact on water security

Ede Ijjasz-Vasquez's picture
Every 2 to 7 years, the cyclical warming of Pacific Ocean waters triggers a global pattern of weather changes that can be felt across many different parts of the world. This phenomenon, known as "El Niño", translates into intense rainfall and floods in certain areas, and severe drought in others. Due to its impact on precipitation, El Niño can seriously undermine water security, decrease agricultural yields and threaten livestock–putting considerable pressure on the livelihoods of affected communities.
 
Ahead of World Water Day 2016, Lead Disaster Risk Management Specialist Christoph Pusch explains how the World Bank helps client countries anticipate, respond to, and recover from El Niño-related shocks such as droughts or floods.

Where water and climate change meet

Water Communications's picture

This week, the 2015 Paris Climate Conference, or COP21, will gather countries that want to take action for the climate. A central topic of these discussions will focus on the intersection of water and climate change.

Combating climate change is everyone’s business. Reducing emissions and investing in renewable energy, improving city planning and building design standards, developing more efficient transportation, and reducing deforestation (among others) all play key roles in mitigating the effects of climate change. At the same time, countries, and industries, will also need to adapt to changes in the climate as they unfold. Since climate change will significantly increase the variability of rainfall, different parts of the world will become more vulnerable to floods or droughts. 

“Water scarcity and variability pose significant risks to all economic activities, including food and energy production, manufacturing and infrastructure development,“ said Laura Tuck, World Bank Group Vice President for Sustainable Development during a recent press conference at COP21. “Poor water management can exacerbate the effects of climate change on economic growth, but if water is managed well it can go a long way to neutralizing the negative impacts.”

Mauritania’s race against the rising sea

Nathalie Abu-Ata's picture
Photo by Nathalie Abu-Ata / World Bank


“If we don’t take action now…the city of Nouakchott will soon be underwater.” These words, spoken by Mauritania’s Minister on Environment and Sustainable Development Amedi Camara, during a recent workshop in the country’s capital city, echoed a recurrent theme during our visits with Mauritanian authorities and local communities alike. They have stuck with me since.

Floods are not a new phenomenon for Nouakchott. A busy port city on Africa’s west coast, Nouakchott is mostly below sea level and is particularly vulnerable to rising groundwater levels, seawater intrusions, porous soils, sand extractions, and heavy rains in low-lying areas. Poorly planned port infrastructure has dramatically altered the dynamic and flow of sediments along the coast leading to substantial erosion in the city’s south (up to 25 meters annually in some years).

To make matters worse, severe and sometimes deadly floods have struck the city in recent decades. Extreme weather and human interventions have played a significant role in making the capital, with one-third of the population, or 1 million people, increasingly vulnerable to floods. 

World Bank Helps With Flood Recovery Efforts in Serbia

Laura Tuck's picture

Laura Tuck, Vice President for the Europe and Central Asia region for the World Bank, discusses the World Bank's role in assisting Serbia with recovery and reconstruction following recent floods, and other economic reforms in the country.

Floods in The Balkans

Ellen Goldstein's picture

Ellen Goldstein, The World Bank's Regional Director for Eastern Europe, talks about the Bank's response to devastating floods in Bosnia and Herzegovina.

Thailand after the floods: When communities own their change

Flavia Carbonari's picture

In 2011, Thailand suffered the worst floods in half a century. The flood crisis impacted more than 13 million people. About 97,000 houses were damaged and entire villages and cities were under water for months.

House in Ayutthaya affected by the 2011 floods
House in Ayutthaya affected by the 2011 floods

Three years later, Thailand has been able to deal with the worst of the impacts but some of the poorest households are still struggling to recover. We visited 10 affected communities in Ayutthaya and Nakhon Sawan as part of the supervision of the Community-based Livelihood Support for Urban Poor Project (SUP). We could still see the water marks on their walls, damaged ceilings, and wobbly structures. The unrepaired houses stuck out but just as striking was the strong sense of community in the area. We were reminded that villagers came together to overcome the worst natural disaster most of them ever witnessed in their lives.

The flooding led to better disaster risk management in the neighborhoods  that are most at risk. Local governments have taken the lead. But the disaster has also, just as importantly, mobilized ordinary citizens in some of the most deprived communities. Here are some of their stories:


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