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Disasters

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.

How change happens (or doesn’t) in the humanitarian system

Duncan Green's picture

I’ve been in Stockholm this week [February 13-17] at the invitation of ALNAP, the Active Learning Network for Accountability and Performance in Humanitarian Action, which has been holding its annual meeting on the banks of a frozen Swedish river. I was asked to comment on the background paper for the meeting, Changing Humanitarian Action?, by ALNAP’s Paul Knox-Clarke.  I read the paper on the flight over (great believer in Just in Time working practices….) with mounting excitement. It’s a brilliant, beautifully written intro to how change happens (or doesn’t) in the aid business, and to a lot of different schools of thought about change.

The paper starts off with the widespread frustration in the humanitarian sector. Despite dozens of new initiatives, impressive sounding statements and resolutions, and endless organizational change processes, ‘everything has changed, but nothing has changed’ in the words of one African humanitarian veteran.  Changes include an avalanche of information technology, the rise of cash programming, geopolitical shifts towards new donors, growth in the number and size of humanitarian emergencies, organizations and the budgets allocated to them. Yet still people ‘did not see these ‘big’ changes as having made a real difference to the lives of people affected by crisis.’ So the paper is as much as study in how change doesn’t happen as how it does.

The bit of the paper that really grabbed me was the succinct summary of three conventional models of change that underpin humanitarian thinking, and three new ones that could shed new light. None of them are definitive; all contribute to a deeper understanding.

A new partnership to enhance the climate resilience of transport infrastructure

Shomik Mehndiratta's picture
Photo: Norsez Oh/Flickr
Since 2002, more than 260,000 kilometers of road were constructed or rehabilitated by World Bank supported projects. For these investments, and future Bank transport investments to really realize their intended impact supporting the Bank to achieve its twin goals, we believe it is critical that they are resilient to climate and possible climate change.
 
Already transport damages and losses often make up a significant proportion of the economic impacts of disasters, frequently surpassing destruction to housing and agriculture in value terms. For example, a fiscal disaster risk assessment in Sri Lanka highlighted that over 1/3 of all damages and losses over the past 15 years were to the transport network. Damage is sustained not only by road surfaces or structures, but also by bridges, culverts, and other drainage works, while losses occur when breaks in transport links lead to reduced economic activity.
 
Along with additional stress from swelling urban populations worldwide, rising sea levels, changes in temperatures and rain patterns, and increasing severity and frequency of floods and storm events are the key climate change factors that make conditions more volatile. Ultimately it is these scenarios and their potential outcomes that threaten the longevity and functionality of much existing transport infrastructure. Indeed, damage to transport infrastructure and consequent disruption to communities from climactic events is a growing threat.
 
Compounding the challenge of addressing these conditions is the difficulty that exists in precisely forecasting the magnitude, and in some cases the direction, of changing climactic parameters for any particular location. Meanwhile, the risk of wasting scarce resources by ‘over designing’ is as real as the dangers of climate damage to under designed infrastructure.
 
To identify the optimal response of our client governments to this threat and to ensure that all transport infrastructure supported by the Bank is disaster and climate resilient, we have created a joint partnership between the Bank’s transport and disaster risk management (DRM) communities – a partnership of complementary expertise to identify practical cost-effective approaches to an evolving challenge. We have come together to better define where roads and other transport assets should be built, how they should be maintained, and how they can be repaired quickly after a disaster to enable swift recovery.

Three misconceptions in the way of better housing policies

Luis Triveno's picture
Also available in: 中文

Photo by Dominic Chavez / World Bank

​While the need for housing is widespread, individually people have different needs—depending on whether they are single, married, senior citizens, families with children, or members with disabilities. Despite the best of intentions of policymakers, "a roof overhead" remains an elusive goal for a large majority of the world’s people. Most households cannot afford even the cheapest house that fits their needs and qualifies as “decent,” and no government alone can close this gap with subsidies. Nor are we on track to build the 300 million new houses needed to close the housing gap by 2030.

What’s missing? At least three misconceptions stand in the way of better housing policies: 
 

Stronger together: Stepping up our partnerships with the UN

Hartwig Schafer's picture

A few years ago, West Africa was gripped by the Ebola outbreak. The onset of the virus devastated communities and weakened the economies of Guinea, Liberia, and Sierra Leone.

Ebola moved quickly and an immediate response by development partners was badly needed. The governments of the three affected countries requested assistance from UN agencies and the World Bank to lead a coordinated effort to curb the epidemic. The Bank responded by restructuring ongoing health projects to free up resources for the governments to quickly contract UN agencies.  

Assessing disaster risk in Europe and Central Asia – what did we learn?

Alanna Simpson's picture
Heavy rains on June 13-14, 2015 caused a 1 million cubic-meter landslide to flow down the Vere River valley and damage the capital city of Tbilisi, Georgia. (Photo via Wikimedia Commons)
Across the Europe and Central Asia region today, policymakers are confronted daily with a wide range of development challenges and decisions, but the potential impacts of adverse natural events and climate change – such as earthquakes or flooding – may not always be first and foremost in their thoughts.

Admittedly, the region does not face the same daunting disaster risks as some other parts of the world – especially in South Asia, East Asia and Latin America – but nevertheless, it is far from immune to the effects of natural hazards – as the past clearly reminds us.

Upgrading Apia’s main road, a path to climate-proofing Samoa’s future

Kara Mouyis's picture
Vaitele Street, Samoa
Vaitele Street is considered the most important section of road in Samoa and in 2016, through the Enhanced Road Access Project, it received a critical upgrade and extension.


Driving from the airport into the city of Apia, the capital of Samoa, is a great introduction to the country. Villages line the road with gardens filled with colorful flowers and palm trees. Hugging the northwest coastline, the road sometimes comes as close as five meters from the shoreline, giving passengers truly spectacular views of the Pacific Ocean.

While it’s a scenic introduction to Samoa, this drive is also a stark reminder of just how sensitive the country’s coastline is to erosion and damage. More than 50% of West Coast Road, Apia’s main roadway, sits less than three meters (9.8 feet) above sea level and just a few meters from the shoreline, making it highly vulnerable to damage and deterioration. When tropical cyclones, heavy rain, king tides and storm surges hit these coastal roads, they can lead to erosion, flooding and landslips, causing road closures and threatening the safety of the people who use them.

100 Days After Matthew, Seven Years After the ‘Quake’: Is Haiti More Resilient?

Mary Stokes's picture

The world’s third most affected country in terms of climatic events, Haiti seeks to better manage natural hazards to improve resilience


Haiti is highly vulnerable to natural hazards. Situated within the north Atlantic hurricane belt, andsat on top of the boundary between the Caribbean and North American plates, the risks are constant. However, this does not mean that disasters are inevitable.

A year of building sustainable communities in 12 stories

Andy Shuai Liu's picture
What are some of the key issues that will shape global development in 2017?

​From addressing the forced displacement crisis to helping indigenous communities, and from implementing the “New Urban Agenda” to enhancing resilience to disasters and climate change, one thing is clear: we must step up efforts to build and grow economies and communities that are inclusive, resilient, and sustainable for all—especially for the poor and vulnerable.
 
In the timeline below, revisit some of the stories on sustainable development that resonated the most with you last year, and leave a comment to let us know what you wish to see more of in our “Sustainable Communities” blog series in 2017.

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