resilient by nature - marco pluijm june 28 2016

(c) Marco Pluijm / June 2016 1

Resilient by Nature Climate Change Extreme Event Resilient Coastal Infrastructure, an Innovative Approach Marco Pluijm M.Sc. Independent Senior Expert Ports and Coasts Key Elements: Climate Change; Extreme Event Impacts; “Resilient by Nature” ; “Connecting Landscapes“ ; Integral Solutions; Examples Introduction The often devastating effects of hurricanes and other climate change driven extreme events are widely known. Much less attention goes to those systems, which are able to survive these impacts without too much damage. For just that reason and so it doesn’t appear as a news item in the media. Those systems seem to have their own natural resilience built in, survive and recover time after time. It is these features on which this paper focuses and on how that knowledge can be used for plan, design and build extreme event resilient coastal infrastructure. By translating their - what seem to be - unique features into more generic processes and dimensions and to apply those findings and concepts to areas which are not able to cope with these phenomena, such as parts of the US and a number of Small Island Development States. With some examples about how this would look like in terms of integral solutions. A concept from here on named and referred to as the Resilient by Nature© approach. Approach Learning from nature is an approach which is not uncommon in the world of marine design and construction. Reference in this respect is made to a visionary engineer Honzo Swašek, who in 1979 for the first time published his “Building with Nature” concept. An approach which came within reach on the backbone of the large Delta works in the Netherlands. With his thorough understanding of coastal processes, he saw the potential of applying the then developed sophisticated knowledge, tools and equipment to the design and construction of other coastal infrastructure works. New solutions came to fruition. The design rules and practices came later. Such as for instance the Guidelines for Dune Safety (Rijkswaterstaat, 1984) and the Beach Nourishment Handbook (Rijkswaterstaat, 1988) A similar approach is proposed here. Translating what can be learned from systems with a natural resilience. And apply this knowledge elsewhere. The imminent need is there. With today’s pressure on low lying coastal areas, the frequency of and the way these areas are facing the consequences of climate change driven impacts, it is now the time to step up to the next level of building with nature, named “Resilient by Nature“ Natural Resilience Resilience can be defined as “the ability to prepare for and adapt to changing conditions and to withstand and recover rapidly from one or more disruptive events” [Ref. NIST, Towards a More Resilient Community, US Dept. of Commerce, October 2015] In this case the focus is on natural habitats and features which are able to survive and recover from extreme event impacts such as hurricanes, excessive rainfall and flooding, but also on a much larger and continues scale, changes in operational wave climates, affecting the day-to-day operations in many ports along coasts of for instance West Africa and Australia. Many of those ports are suffering from this phenomenon, but some along the same coast are not and for a reason. These are the qualities to look for and investigate. Focus on


systems which seem to be able to deal with these effects without too much impact. Or no impact nor damage at all. A number of these systems have been identified and analyzed on their unique characteristics and presented here as examples. To mention are:

• Barrier islands A number of barrier islands in the Mississippi Delta appear to have a natural resilience towards hurricane impacts. For instance Dauphin Island, which has survived a number of hurricanes in succession, without too much damage to the island and on the island. On one occasion the island did develop a gap, breached, which helped to understand what the limits of resilience in this respect are. With thorough understanding of the natural processes and due to the natural characteristics of the system, this gap could be fixed with relative simple means. The conclusion in this case is that the system’s natural resiliency performed well during all events and only once needed a bit of human support to recover, still based on natural processes too.

• Mangroves These systems are renowned for their natural resiliency, mainly due to their extensive and spread out root systems. Mangroves are very effective in reducing waves and therefore in protecting vulnerable coastlines. The systems themselves are vulnerable to climate change as such. Which needs careful monitoring and when needed, mitigation where possible. Healthy mangrove areas usually fully recover after an extreme event. In some cases, for instance when large quantities of sediment have moved around during the storm, settled and cover their root systems, human intervention may be required to remove that overburden. For instance by controlled flushing. An option, which will be highlighted later on in this paper.

Figure 1: Dauphin Island (US) under normal conditions and spilling during an extreme event Ref : Wikipedia

Figure 2: Mangrove System Ref : wangateauharbour.org


• Dune coasts

Like mangroves, dune coasts are renowned for their natural resiliency. Due to their natural dynamics and flexibility they are able to withstand super-storms and recover afterwards. During the storm event the dune-front erodes, with the eroded sand settling on the foreshore, thus reducing the wave impact, slowing down the overall effect. After the event, cross-shore sand transport brings the sand back, with the wind taking care of the dry parts, settling again along the dune-front.

• Polder systems

Polders in this respect might seem to be a bit of an odd one. Because polders by definition are manmade. Still in terms of natural resiliency, a lot can be learned from these systems once built. For instance how their structure of canals, levies and buffers manages to cope with extreme events. Even after flooding. For instance as integral element in flood defense systems. Protecting the area behind, even when the polder area itself would get flooded. An attribute which in itself can be used as part of the overall resiliency of a coastal area. In particular in those cases where the polder is used for nature development and conservation. Like the Oostvaardersplassen in the Netherlands, where inside the diked area (the polder), a large part has been developed into a nature conservation area. It is the characteristics of this area, actually an eco-buffer, which helps to develop the polder itself, and so the area around it, into a resilient and more sustainable environment. And although this polder is situated inland, the same capacity can be used for enhancing the resilience of coastal areas in terms of reducing direct storm impact and flooding.

In summary, four examples of systems with built in natural resilience towards extreme event impacts, which form part of the basis for the “Resilient by Nature” approach, presented here. Examples for solutions, also in combination with each other, for places less able to cope with the challenges these impacts impose with increasing frequency and intensity.

Figure 3: Dune Coast Ref : ntpressoffice.wordpress.com

Figure 4: Nature Conservation Polder and Landscape Ref : Wikipedia and ANP Extra


Resilient by Nature With reference to the above, the “Resilient by Nature” approach is based on what can be learned from natural systems around the globe, which are able to survive and recover from the impacts of climate change induced extreme events. Experiences translated into basic dimensions, practical guidelines and tools for the benefit of other places, which are not able to respond in a similar, adequate way. Solutions either as standalone components or in combination. In which case reference is made to what is called “Connecting Landscapes”, highlighted later on in this paper. All solutions based on proven performance. Sharing the ability of natural resilience and sustainability. Systems which can recover either fully by themselves or sometimes with a little help from outside. Where “help from outside” is defined as “with local means”. For reasons of sustainability and efficiency, it is recommended to strive for solutions based on the use of local craft and capacity. A capacity which was demonstrated for instance in Hue, Vietnam, using sand bags and local labor to close a major tidal gap in a barrier island, developed after the devastating floods of 1999. No external efforts were called in. Instead of bringing in international contractors, the Government decided to solve the problem with local means. This is not a unique example and should be one of the basic principles to follow throughout the whole “Resilient by Nature” approach. Toolbox Tools Based on the lessons learned and analyses of the various natural systems, a number of different elements, tools, emerge as building blocks which can be used for enhancement of more vulnerable systems elsewhere. The examples from toolbox in its current format contains the following elements or tools:

• Hurricane proportioned barrier breakwaters In analogy with the behaviour of the barrier islands in the Mississippi Delta, this concept can easily be translated into breakwater solutions, or other coastal infrastructure, elsewhere. Main determining parameters are found in width, height and length. Based on the principle of relative undisturbed flow over and around the barrier island during the event, instead of attacking it as a rigid structure. Time has shaped these features according to the wide variety of exposure they have faced during their lifetime. It’s these dimensions which indicate how similar features can and should look like on other locations, in another place. The processes usually are the same, their relative interaction can vary. The concept itself, with addition of general understanding of coastal processes, can shape any solution elsewhere. Provided the natural materials (sand or clay) are available.

Figure 5 : Dauphin Island as an example of a Barrier Breakwater Ref : USGS


• Sequential breakwaters Offshore breakwaters can work well under average conditions, but do have a reputation of low efficiency with regard to extreme conditions. This changes when building them like natural sandbank systems With the right dimensions in terms of height, width and interspacing in relation to the wave attacks they need to be able to encounter and reduce impact, based on their natural dynamic behaviour. Depending on the local conditions built as sand banks or as hybrid solutions by adding hard substrate (rock/concrete elements) or vegetation (eco shields)

• Eco Shields

Enhancement of natural coasts’ resiliency by means of vegetation. Zones of mangroves or other vegetation, in front of or along a coastline, protecting the area itself and the hinterland behind it from erosion and flooding. In case the natural environment is not immediately suitable for such a solution, a combination with a contained, polder approach might provide the answer (see below). Eco shields and coastal vegetation can get damaged due to for instance vast sedimentation and debris during an extreme event. Tidal and nearby river flow shall be strong enough to remove that sediment overdose, but when the quantities are too large, the natural system might need help from outside. For instance by controlled flushing, which in itself can be driven by (controlled) natural processes.

Figure 6 : Near Shore Sand Banks at Low Tide Ref : www.mumm.ac.be/NL/Monitoring

Figure 7 : Example of an Eco Shield : Guyana Mangrove Restoration Project Ref : www.mangrovesgy.org/home/


• Extreme Impact Relief Polders One of the traditional criteria for a polder, is keeping the (sea) water out at all times, in order to protect what is inside the diked area from flooding. According to the Resilient by Nature approach, as an alternative, polders are considered as an effective tool in protecting vulnerable coasts, following a different idea. Polders as impact relief instrument, actually meant to get flooded during extreme events. With dikes designed as spilling levies or weirs. Which allows the water to come in a controlled manner, slowing down the direct impact on the coast behind, while the polder fills up with seawater. Vegetation in the polder can enhance this process and so the degree of protection or relief. After the event, intruded salt water is pushed out by the surface storm water run off, which flows into the polder from the landside. Again, controlled, via large capacity drains. In the period before and after the impact, the area inside the polder can be used for all kinds of purposes, such as agri- or aquaculture. In terms of climate change resiliency, development as eco-polders with impact resistant vegetation and a varied landscape, is preferred. Vegetation chosen in accordance with what is most effective and viable for that specific region. This concept may lead to an additional advantage or quality. For instance part or all of the polder can be used for enhanced flushing. A subject mentioned earlier. In analogy with a facility which is in use along the German coast of the Waddensee, at Neßmersiel. Where a polder (or: Spülsee) gets flooded with the daily tides and discharges each time once filled up. Thus keeping the local shipping channel (fairway) free from siltation for over 30 years now.

Figure 8 : Fully Detached Nature Conservation Polder Ref : www.bndestem.nl/foto-s/

Figure 9 : Neßmersiel (Germany) Flush Basin (Spülsee) Ref : Google Earth and Apple Maps


Such (semi-) natural, gravity driven flush mechanism could work with mangrove zones which are threatened by post event siltation. Or ports and fairways suffering from post event clogging up with sediments or debris. A common problem and often hard to tackle in terms of response time, availability of equipment or required draft and capacity. Such a natural flow system could solve or reduce the problem.

Extreme event impact relief polders can be built near-shore, at relative short distance in front of a shoreline as kind of detached “breakwaters” or attached to the coastline.

• Offshore Structures

Apart from the climate change induced short event impacts, another related phenomenon are the changes in the world wave climate. In particular the rapid changes in long wave energy and bound long waves along various coasts in the world. Causing an increase in downtime in ports along those coasts, in particular for the handling of container vessels. One of the options to deal with this effect and make ports more resilient in this respect, is to push the affected port infrastructure out to deeper water. Towards a suitable distance from the coastline, where for instance resonance plays a much lesser role and the operational wave climate becomes less hostile. By doing so, offshore port infrastructure offers opportunities for additional benefits too. Such as homeland security, enhanced bio diversity, commercial fishing (artificial reefs) and tourism. During and after extreme events, offshore ports can provide the necessary backup in terms of deep-water port infrastructure, needed for delivery of goods and equipment and serve as Disaster Relief Centre. While by doing so, onshore the pressure on the available land areas becomes less, with a reduction in need for more onshore port development, or even the opposite, when former terminals which have become inefficient, can be redeveloped into nature conservation areas. Which in themselve can contribute to the overall resiliency with regard to extreme event impacts of that area.

Figure 10 : Post Event Masses of Debris Ref : www.internal-displacement.org

Figure 11 : Yang Shan Offshore Port Ref : www.chec.bj.cn


Potential vulnerability of the port equipment (such as the gantry cranes) during an extreme event can be dealt with by designing them as low drag port infrastructure (reduced turbulence).

In summary, what is presented here is variety of tools as examples of what the Resilient by Nature approach brings, based on evaluation of the performance of a number of existing systems around the globe. Over time more examples, tools, are expected to follow when this concept is adopted by the international community. Similar to what happened with Building with Nature. Developing guidelines and tools as things move forwards. The next step in the process is to demonstrate how this translates into actual solutions for places without or with insufficient natural resilience in this respect. Two examples are given. One for Vanuatu, a Small island Development States (SDIS’s) and one for the City of New York. USA. Examples of “Resilient by Nature” Solutions Each coastal area hosts a great deal of functions. One of the specific characteristics of coastal environments is that they keep on changing their dimensions with time. Functions may be well defined, due to their characteristics, but their physical appearance most likely keeps on changing. It is very much a 4-Dimensional environment. In this respect it is probably better to talk about changing landscapes rather than (discrete) functions. Landscapes which are interrelated and connected. When one changes, others will respond or follow. In terms of addressing the qualities and needs for resiliency of coastal areas, mapping of those needs and assessing their interrelations is done according the method of “Connecting Landscapes” (see figure 12) Where the Greek symbol “δ” stands for variety and change.

An idea about a number of (generic) landscapes is given in figure 12. How this works out for two more specific cases, e.g. SDIS’s (Vanuatu example) and New York, USA, is illustrated in figure 13. It is noted that these figures are for demonstration purposes only and the actual contents are open for debate. One of the recommendations is to further define a number of these cases and start working along this line towards actual integral solutions, suitable to get implemented.

Figure 12 : Connecting Landscapes, the δ Approach


Connecting these images with the toolbox as it is, leads to an array of solutions, depending on needs, opportunities and urgency of the place. But also provides a picture and understanding about what is already there and what is needed to reinstate or enhance natural resiliency.

In particular in case of a number of the SDIS’s, the likely outcome will be that relative small additions are required in order to make significant steps forward with regard to resiliency for extreme events. Especially when adding the suggested polder concept is an option. Being a multi functional add-on with many additional advantages. For the City of New York the picture is probably a bit different. Much is already there. Especially when following the “Resilient by Nature“ approach, when applying barrier breakwaters and concepts such as the disaster relief polders and eco shields (other than mangroves) in combination with wetland conversation onshore. In terms of port infrastructure the City of New York is thought to be a perfect example where an offshore port has significant advantages. Not only for the port infrastructure itself (no draft restrictions or height limitations), but also in terms of Homeland Security and extreme event impact resiliency. Providing adequate deep water port facilities after the event (not impacted by post-event siltation) and cargo (container) handling facilities, as well as many backup functionalities (such as a Disaster Relief Centre or - Mitigation Unit). Under normal conditions the offshore port and provide additional functionalities for commercial fishing (hard sub, artificial reefs) and for instance tourism. Economics The economics behind what’s feasible or not will mainly be determined on the basis of what’s already there, how much modification is required and what to build from scratch with related planning and time scales. Balanced against the immense costs of the economic and financial damage each event causes. Which usually is a staggering amount. The combined damage of the 6 main storm events over the past ten years along the US South East and East Coast, adds up to USD 290 billion. Which is an average of USD 29 billion per year. An event like hurricane Sandy (2012, USD 75 Billion) proves that the damage likely exceeds many times the investments, needed for creating and maintaining an adequate resiliency level. With the “risk” that a similar, second event will never hit the State of New York again. Still, with the rapid increase in climate change induced extreme events, a matter of serious risk assessment. On the basis of which the Dutch have built their country. And when that went wrong in 1953, with the big floods in the south of the country, the Delta Plan was pulled

Figure 13 : Connecting Landscapes, SIDS (Vanuatu) and New York (USA) Examples


out and by itself changed the world of flood protection, environmental impact assessments and marine construction. Justifying every penny spent since on events that most likely will never happen again. When Honzo Svašek kicked off his Building with Nature approach in 1979, no one could foresee the huge benefits that would bring and has delivered since, globally. An almost global industry has actually been built on it. Environmental friendly construction became a universal statement. The same can happen with “Resilient by Nature”. To begin with the right mindset and approach, followed by actual cases to underpin and provide further support and expand the number of tools in the toolbox. Making optimal use of lessons learned and translating those into guidelines and actual project proposals for vulnerable areas around the globe. All based on proven technology and concepts. Tailor made and adjusted to local circumstances. Conclusions. Climate change induced events come at greater pace and with an increase in intensity and duration. The negative effects are often highlighted in the news. Not so much or not at all, the good news about systems which seem to survive and overcome these events without too much impact or no impact at al. It’s these systems the “Resilient by Nature“ approach is focusing on. On what can be learned from nature and how that knowledge and experience can be translated and transferred into solutions for more vulnerable places elsewhere, apparent less able to cope with these events. In order to determine the viability of this approach, a number of systems have been analyzed and their effectiveness potential assessed. With promising results. It’s now a matter of stepping up to the next level. Identifying and investigating concrete cases in other parts of the world where the “Resilient by Nature“ approach and tools can be implemented. Such as on a number of affected SIDS’s (Vanuatu) and heavily urbanized areas such as the City of New York or Singapore.

resilient by nature - marco pluijm june 28 2016

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