Disasters

Climate is changing… So the way we manage roads needs to change as well

Photo: Christopher R. Bennett/World Bank

Few things are more depressing than seeing the damage caused by cyclones on transport infrastructure. Especially when it is a causeway that was only formally opened less than one month before the storm. That is what I found in early 2014 when participating in the Tonga Cyclone Ian Post Disaster Needs Assessment. The cyclone was a typical example of the heavy toll that climate change is taking on transport infrastructure, particularly in the most vulnerable countries.

Engineers are taught that water is the greatest enemy of transport infrastructure, and unfortunately climate change is leading to an increase in floods and storms, especially within the South-East Asia region. For example, the figure below shows the number of floods and storms for some Asian countries between 2000 and 2008. The significant increase in the number of floods is self-evident.

In 2015, severe floods washed away a series of bridges in Mozambique’s Nampula province, leaving several small villages completely isolated. Breslau, a local engineer and one of our counterparts, knew that rebuilding those bridges would take months. Breslau took his motorbike and drove the length of the river to look for other roads, trails, or paths to help the villagers avoid months of isolation. He eventually found an old earth path that was quickly cleaned up and restored… After a few days, the villagers had an alternative to the destroyed bridge, reconnecting them to the rest of the network and the country.

What happened in the Nampula province perfectly illustrates how a single weather event can quickly paralyze transport connections, bringing communities and economies to a screeching halt. There are many more examples of this phenomenon, which affects both developing and developed countries. On March 30^th, a section of the I-85 interstate collapsed in Atlanta, causing schools to close and forcing many people to work from home. In Peru, food prices increase in Lima when the carretera central is disrupted by landslides because agricultural products can’t be brought to market.

How can we help countries improve the resilience of their transport networks in a context of scarce resources and rising climate uncertainty?

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Over the past three years and a half, our team has been working on a transport project with the state of São Paulo in Brazil. The project involves a lot of traveling, including frequent commutes between the World Bank office in Brasilia and the State Department of Transport in São Paulo (DER-SP)—a journey that is estimated to take 2 hours and 40 minutes. This includes the time to drive from the World Bank office to Brasilia Airport, flight time, and commuting from São Paulo’s Congonhas Airport to the State Department of Transport.

Let’s say that, on a typical Wednesday, the team needs to attend a meeting in São Paulo. To ensure we can make it on time, we plan our day carefully, book our flights and define the right time to leave the office in Brasilia. With a plan in place, we leave the office at 10:00 am and head to Brasilia Airport. The first leg of the trip takes 35 minutes and we manage to arrive early for our 11:00 am flight, which, unfortunately, is delayed by 20 minutes. We land in São Paulo, quickly get out of the terminal, and manage to hop on a taxi at 1:20pm… not bad! We are now on the last leg of our journey, a mere 14-kilometer drive between Congonhas Airport and the meeting place, which is supposed to take only 20 minutes. However, there is a short thunderstorm that floods the city and closes off key streets. This single event leads to complete traffic chaos along the way, and our planned 20-minute transfer from the airport turns into a 1-hour-and-15-minute ordeal. These traffic disruptions have a serious impact on our meeting as well, as some Department of Transport staff cannot join and some items of the agenda cannot be discussed.

This incident may seem anecdotal, but it is a good illustration of our extreme dependency on transport systems and the weaknesses associated with it. Because transport is so critical to our social and economic lives, it is extremely important to understand, anticipate, and minimize the different types of risks that may impact transport systems.

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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.

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.

. 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 , 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, .

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, – 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.

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The modern tramway system in Rabat Salé, Morocco. Photo: LukaKikina/Shutterstock

. On the one hand, such as higher temperatures, increased precipitations, and flooding. At the same time, , and is one of the sectors where emissions are rising the fastest. This statistic alone makes it pretty clear that t.

Yet, before COP21, the transport sector was conspicuously absent from climate talks. The strong, structured presence we saw last year in Paris and this year in Marrakech is finally commensurate with the urgency needed to address the transport-related issues on the climate agenda.

like the Sustainable Development Goals (SDGs) and the Paris Agreement. As an example, over 70% of the Nationally Determined Contributions (NDCs) that countries have proposed to implement the Paris Agreement include transport commitments, ranging from increasing public transport in cities to shifting freight from roads to railways and waterways.

Relief supplies being unloaded from a New Zealand C-130 at the airport in
Tuvalu after Cyclone Pam struck some outer islands. *Photo: Nora Weisskopf*

When disaster strikes, air transport is often the only feasible mode of transportation for first responders and urgently needed relief supplies. Following an earthquake, tsunami or hurricane, most roads, rail tracks and even ports become unusable, as they are blocked for days by debris. Airports, on the other hand, are remarkably sustainable and, within hours, usually become operational again.

Kathmandu Airport: Already crowded
before the earthquake.
*Photo: Charles Schlumberger*

The main reason of this sustainability is that runways are on open space where debris of a disaster can be removed quickly. Furthermore, a runway usually suffers remarkable little damage even by a strong earthquake, such as experienced last week in Nepal or in Haiti in 2010. And even if there are cracks and holes in the runway, modern relief aircraft like C-130s can operate safely for some time.

However, the challenges of operating relief flights can quickly become overwhelming, especially for airports in developing countries that usually experience only moderate traffic. In Haiti, for example, more than 74 aircraft landed on a single day following the earthquake to unload supplies. Such traffic poses risks in the air; air traffic control, often hampered by inadequate or damaged surveillance installations, can’t cope managing all arriving aircraft. On the ground, where tarmac and taxiways are small, congestion quickly reigns which prevents the arrival of more flights.

Disasters

Climate is changing… So the way we manage roads needs to change as well

Preparing transport for an uncertain climate future: I don’t have a crystal ball, but I have a computer

Are roads and highways the Achilles Heel of Brazil?

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

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

A new partnership to enhance the climate resilience of transport infrastructure

Climate-smart transport is a key piece of the sustainable development puzzle

Air transportation – the critical infrastructure when disaster strikes