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The End of the Road? Can a Systems Approach to resilience be applied to roadway and transport systems in coastal cities and communities?

By Jesica Andrews and Rory Walshe


Coastal road damage following Cyclone Pam in Vanuatu

In November of 2013, just before COP19, Typhoon Haiyan devastated the Philippines. One year earlier, Hurricane Sandy sent shockwaves throughout New York City. Extreme weather events such as these bring to light the tremendous need to ensure resilience among systems[1], both large and small, and highlight that even diverse systems half a world away from each other, can learn from one another.

These singular events drove massive human and economic loss. In the Philippines over 6,300 lives were reported as lost, while New York experienced $68 billion USD in economic damages. Both experiences overwhelmed the local communities and the infrastructure they depended on. Similar events continue to occur across the globe.

Extreme events, not limited to hurricanes, typhoons and cyclones, can strike anywhere and have significant impacts on even the most resilient systems, acting as a callous reminder of the fragility of our human worlds in the face of aggravated nature. A previous post on Climate-Exchange explored a systems approach that holistically views the interactions, properties and processes of human, physical or natural systems in relation to climate change driven pressures. This post is an effort to expand on the work contained in the previous post, by relating the conceptualization to real world examples.

The conceptualization can be utilized for any system and any impact. We’ve narrowed down our examples to roadway and transport systems in coastal cities and communities impacted by storm surges. With over 40% of the world’s population living in coastal cities, and climate change induced sea level rise predicted to have significant impacts across the globe, we selected this system hoping that it will highlight the usefulness of the conceptualization and ensure relate-ability and relevance for readers.

Coastal cities are no stranger to interactions with the sea. Large storm surges are not a new phenomenon, but they are changing in frequency and intensity. Most importantly, human knowledge about how to prepare and respond is growing. The response options available to a community depends on the system in which they live[2], the extent to which communities alter and adapt their systems in order to safeguard them will determine their level of resilience. In this analysis, we are concerned with how systems are structured prior to impact, followed by how they rebound or fail to rebound afterwards. Some communities will have early warning systems in place, some will have barriers established to hold back storm surges, others will have areas of the community which become unusable during a surge later returning to life, and still others may accept the total loss of some amount of territory. The way in which communities evaluate their systems prior to an impact and put in place resiliency measures will have vastly different outcomes for the community; from total recovery to total system failure.

The original post defined 6 types of systems: Resilient, Absorptive, Adaptive, Failed, Transformative, and Maladaptive. The table below presents a visualization of this systems approach to adaptation, which illustrates properties of resilience when responding to climatic stressors. The red impact/stressor arrow represents environmental stressors. A fourth column has been added to the original conceptualization. In this column a hypothetic example that resides within our selected system is given. The newly added column demonstrates how the new visualization can be applied to real world scenarios.

An applied Systems Approach to Resilience

(click on the table for a larger version)

The hypothetical examples are easy to imagine, worth referring to as a bridge between the concepts and the real world. The real world is a bit messier. Primarily, it does not provide us with perfectly comparable examples or control groups. Differences exist between communities with regards to their geographic context, economic capital, experience and availability of technology and knowledge, among many, many other factors distant in space and time that influence a system’s resilience to an impact (in our case, a storm surge). By electing to look at “roadway systems in sea-side cities and communities” we are attempting to limit the endless array of examples we could pull from, and make them slightly more comparable. By corresponding an existing system to the conceptual systems in this way it is rather superficial and subjective. We acknowledge this. It’s an imperfect world.

The following table gives real world examples from Asia, Europe, North America, and the Pacific Islands. It is not an attempt to pass judgment on the success or failure of these approaches. They are all operating in distinct contexts under drastically different circumstances. The exercise is simply meant to apply concept to reality, and aid practitioners with practical examples.

  1. Resilient System – Thames Barrier, London, United Kingdom

SR1Operational since 1982, the Thames Barrier is a massive steel structure crossing a 520m section of London’s River Thames. Its purpose is to prevent all but the easternmost neighbourhoods of London from being flooded by exceptionally high tides and storm surges moving up from the North Sea. When needed, it is closed (by raising large walls from the sea floor) during high tide; at low tide it can be opened to restore the river’s flow towards the sea and allow for the passage of ships. The enormous wall can hold back 90,000 tons. Small openings allow it to slowly readjust to match the water level again. The Thames Barrier protects tens of millions of people and billions of dollars worth of property, operates in just minutes, and has 2 failsafe mechanisms (individual controls on each door and manual cranks and doubled arms for moving the doors if the first arm fails). It can take between 15 to 90 minutes to put in place, however if closed all at once it can send a deadly rebound wave back down river. Thames Barrier has experienced 5 closures per year since 1983, but as many as 30 per year are expected in coming decades due to climate change.

The Thames Barrier is a good example of a resilient system because it demonstrates how the capacity of London’s roadway system remains untested. We can imagine that the impacts of its failure would be devastating. The London roadway infrastructure is not expected to improve as the storm surges intensify and become more frequent. Instead the system will remain a resilient one so long as the Thames Barrier is able to withstand future storm surges. However, if the storm surges ever overwhelm the Barrier, the system will be changed and the resulting system will either transform-and-adapt, or it will fail, bringing down billions of dollars of infrastructure with it.

  1. Absorptive System – Fire Island, New York, United States


Fire Island is 9.6 square miles of natural buffer between Long Island, New York City and the Atlantic Ocean. The physical attributes of the island have changed over time, including one major inlet break in 1683 that separated it from what is now Jones Beach Island. It is now partly inhabited (including 4,500 homes) and partly wilderness reserve. During Hurricane Sandy the island was severely damaged. Three breaches occurred, as have occurred many times before. Two of the breaches are being closed, but one, occurring on the nature reserve, remains open. It has had the effect of improving water quality by flushing out the Great South Bay, but some homeowners have cited the open breach as a source of increased flooding. Some 80% of homes were flooded, and approximately 90 homes were completely destroyed. However, damage was not as great as in other areas, which has led some officials to credit a dune replenishment program that was recently put in place.

Local officials are now putting in place a $207 million USD project to enhance the sand dune buffer on the east side of the island to protect against future surges. The approved plan will require that some 400 oceanfront property owners sign easements (losing part of their property to the new projects), while about 40 owners will be required to forfeit their property entirely. The 40 home sites equate to less than 1% of the homes on Fire Island, and the easements just over 10%. In this example, one can conclude that the system has been altered in shape and form but not too significantly.

Photo Credit: USGS, 2012

Photo Credit: USGS, 2012

  1. Adaptive System – Coastal Mangroves, Vietnam


The value of mangroves for coastal storm surge protection is well established. Mangroves in deep sediment on high islands can act as effective buffers to coastal impacts of climate change. This is particularly true of Vietnam, with three-quarters of its landmass occupied by densely forested mountains or hills which has resulted in a significant proportion of infrastructure – including roads – being located on the coast.

The Coastal Wetlands Protection and Development Project, in the Mekong Delta region ran from 1999-2007. In this project, mangrove plantations were established with the objective of providing protection and increasing ecosystem goods and services for coastal communities. One of the primary benefits of coastal mangroves is their ability to reduce storm surge water levels by slowing the flow of water and reducing surface waves. It would be problematic to point to a single surge event that has valorised these efforts, but there have been several significant storm surges concomitant with typhoons in the past few years (including Typhoon Usagi and the aforementioned Typhoon Haiyan as a Severe Tropical Storm in 2013). The impacts of which would undoubtedly have been more severe without the existence of coastal mangroves given that, as Alongi (2008) details, mangroves provide significant protection in catastrophic events.

Mangroves are a great example of an adaptive system because they are able to sustain certain impacts and bounce back through natural regeneration. While mangroves can be said to protect roads, it cannot be said that roads protect mangroves. Instead the construction of roads or other infrastructure such as sea walls, dams, aquaculture ponds and dikes are a threat to Mangroves in that they disrupt the delicate hydrological regime necessary to sustain them. This emphasizes the need for consideration of the whole system rather than single components. Moreover, mangroves provide a needed and sustainable material resource, as well as offer large carbon capture benefits.

  1. Failed System, Coastal Roads, Tuvalu


The coral atoll nation of Tuvalu is often referred to as being on the front lines of climate change and with an average height of less than 2 metres (6.6ft) above sea level, it is one of the counties most at risk from sea level rise. As well as its very low-lying topography, it is located right in the middle of the area in the Pacific in which sea level has risen the most steeply (Becker et al. 2011). Perhaps unsurprisingly the effect of king tides and tropical cyclone storm surges are therefore having a highly damaging impact. The surge that accompanied Cyclone Pam in March 2015 caused a considerable amount of damage to roads and infrastructure (Red Cross 2015).

Despite the fact that Tuvalu has less than 10km combined drivable roads, it offers a valuable example of failed system since the critical function was entirely lost before reconstruction and recovery. That the roads are rebuilt (and some sections entirely) is an interesting distinction, and begs the question; exactly how should reconstruction feature as a component of resilience in our systems approach? But what makes Tuvalu (and other low-lying atoll nations such as Kiribati, Maldives, Marshall Islands and Tokelau) even more relevant as an example is not its current state but rather its future predicament. Unabated sea level rise combined with wave damage, ocean acidification and coral bleaching is estimated to result in Tuvalu being overtopped by the sea between mid to late 21st century (Dickinson 2009). It therefore is one of the few conclusive examples where unless drastic action is taken (with very limited options such as relocation like the I-Kiribati to Fiji) total system failure will occur.

  1. Transformative System – Twin span highway, New Orleans


In 2005, Hurricane Katrina devastated New Orleans, a city that sits below sea level between Lake Ponchatrain and the Mississippi River. At its lowest point the city is about 7ft below sea level. One means of reaching the main land from the city is over New Orleans now destroyed “twin span” bridge. The original bridge was just 8.5ft (2.5) above sea level and was rendered useless after Hurricane Katrina hit. Damage to this bridge and several other major roadways, left just one point of access for New Orleans (Route 11) following Katrina. In 2006, New Orleans responded by constructing two three-lane bridges 30 feet (9.1 m) above the surface of Lake Ponchartrain, with an 80-foot (24 m) high-rise near Slidell, worth $803 million. Each span is 60 feet (18 m) wide, consisting of three 12-foot (3.7 m) lanes, and 12-foot (3.7 m) shoulders on each side. The new roadways were completed by 2011 and what remained of the old Twin Span was destroyed shortly after.

The New Orleans system is an example of a transformed system in that critical functions were lost, and following the impact the system was improved. The new bridge accommodates 50% more traffic than the original Twin Span and its greater clearance and new construction design reduce the bridge’s vulnerability to future storm surges.

  1. Maladaptive System – Sea Walls in Upolu, Samoa


As the original systems article highlighted, transformational adaptation – positive or negative – is not dependent on system failure, or even the presence of a stressor. However for a range of social, economic and political reasons, adaptation is often left until the arrival of significant impacts have removed the option to act preemptively. The Small Island Developing State of Samoa in the South Pacific did not experience a complete failure to its coastal roads, but it did experience coastal erosion (particularly during Cyclone Ofa in 1990) that led it to invest heavily in the construction of Seawalls around the capital Apia and in other developed stretches of Upolu Island.

In several ways this use of seawalls can be considered a maladaptation. While the intended purpose was a success (the protection of built infrastructure for example during Cyclone Evan in 2012) there are considerable knock-on negative effects in other areas. Erosion of material in front of sea walls (such as the beaches which make Samoa so appealing to tourism) is intensified since seawalls create damaging standing waves. The areas adjacent to sea walls also experience increased coastal retreat since the construction of sea walls disrupts the process of long-shore transport, by which beaches are naturally replenished. Both these processes intensify the encroachment of the sea onto coastal roads in unprotected areas, which are often right on the coast due to Samoa’s topography. There are also multiple issues associated with the effect of constructing seawalls on drainage, the hydrological regime and the water table. In several cases the sea wall has caused either stagnant or salt water to pool behind the wall, which can exacerbate damage to coastal roads in its own right or via the alteration of local ecology such as the mangroves example detailed in system 3.


The above concepts and the corresponding real world examples serve to help readers and practitioners understand the concepts laid out in the previous post “A New Systems Approach to Resilience”, but also to inspire provoke deeper consideration of the concepts represented. More recently, as is the tendency for new fields of research, adaptation is becoming better understood with clearer categories and criteria surrounding its implementation. One example is the emerging distinction between “incremental adaptation” and “transformational adaptation”. Cities and communities, many noted in the examples above are beginning to take note of the important difference. Adaptation is not only about reducing vulnerability but exploiting benefits of the inevitable change that is to come.

New Orleans is an example of a severely threatened city that is just beginning to understand that unless things are done differently the city will continue in a highly vulnerable state. Recently, a study by the US National Academy of Sciences noted that seawalls and levees reduce vulnerability, but should not be expected to safeguard the city entirely. Ironically, as a result of the levees on the river, and canals dredged for oil, gas and shipping, the wetlands that once used to provide valuable ecosystem services including storm protection for the city have been cut in half since the 1930s. In line with this, the city is undertaking an effort to utilize the great Mississippi river to deposit sediment for new wetlands. Several projects including the Mid-Barataria sediment diversion project were approved in 2007 to allow, as well as mimic, the natural process of the Mississippi river. However, funding has come slowly. The wetlands will restore a once existing ecosystem to life, as well as provide a barrier in the case of future storm surges. London is exploring options for a similar project the “Thames Estuary 2100 Plan”.

Applying this systems approach to roads in coastal cities and communities was not an attempt to categorically define the properties of resilience or even the situations that we used as examples. Instead it is our hope that by applying the systems thinking to practical examples we might better understand the differences between systems that respond well to stressors and those that respond poorly. Without these distinctions, the difference between an absorptive system (which more typically is prone to failure at a later date) and an adaptive system (either transformative or maladaptive) are easily overlooked.

In answer to the question: ‘Can a Systems Approach to resilience be applied to roadway and transport systems in coastal cities and communities?” the answer is not only that it can, but that by doing so it is possible to demonstrate aspects of the original visualization which were previously just theoretical. By investigating a small component – coastal roads to storm surges – we are reminded of the understandable urge to compartmentalize, control and isolate elements in order to manage the destructive potential of climate change. This must be resisted because local impacts often result from global scale processes, which can be distant in space and time. Therefore, perhaps systems thinking is a good place to start in order to visualize systems in their wider context. Ultimately applying systems thinking to practical cases should underline the supposition of the original article, that unless meaningful and sustained adaptation is pursued, which accounts for the different forms of adaptation and the full implications of this, then the adaptation community risks simply window-dressing failing absorptive systems rather than effecting valuable change through positive adaptation.

[1] The systems can represent any scale or type of interconnected processes and actors, from global oceanic circulation systems to single rural households.
[2] For the purposes of this post it is not useful to go into the diversity of options available to individuals (i.e. some may have the resources to respond differently than others), but rather to maintain the systems approach in which whole communities can operate.

© Jesica Andrews and Rory Walshe

Suggested citing:

Andrews, J and Walshe, R., 2015. The End of the Road? Can a Systems Approach to resilience be applied to roadway and transport systems in coastal cities and communities?[Online]. Available at: [date accessed].

About Jesica Andrews

Screen Shot 2015-10-16 at 12.51.33Jes is committed to understanding and implementing quality climate change adaptation and resilience programs. She worked in the legal sector and for government before uprooting herself from her native New Mexico to move to Nairobi, Kenya where she works on adaptation in the African context and at the global level. She works closely with the United Nations Environment Programme and other regional and global actors in the adaptation sphere.


One comment on “The End of the Road? Can a Systems Approach to resilience be applied to roadway and transport systems in coastal cities and communities?

  1. Renee Martin-Nagle
    October 21, 2015

    Terrific article! Thanks for enlightening and informing us by sharing your knowledge.

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