Towards a cultural understanding of the value of the intertidal zone
I live on an estuary that is subject to substantial tidal variation, which although not extreme, is sufficient to lull you into a false sense of security and then in a flash, it can wash you out. On 6th December 2013 our coast in Suffolk, UK was subject to a major tidal surge that saw me rowing home over dry land. Home for me is a seagoing vessel, where the intertidal zone is both domicile and workplace.
For centuries our intertidal zone has been an ambiguous territory, both targeted for reclamation and valued as a buffer between dry land and the sea. However due to heightened sensitivity to its uniqueness, the instinctive mistrust of a place that becomes no place twice daily has moderated: now saltmarsh has secured a status within our culture that corresponds to an awakening of understanding. It is a pivotal zone routinely acknowledged as habitat for both fish and avian species, in contemporary parlance it provides an ecosystem service: as a first line of defence by attenuating tidal energy, a carbon sink and by locking up pollutants within its root mass.
I have worked intensively with saltmarsh systems for more than a decade, exploring ways to understand its dynamic and to stabilize it through soft engineering interventions. In the following paper, using case studies from my own experience, I will discuss the shift in awareness vital to enhancing a sense of community ownership, responsibility and affinity for the intertidal environment.
I will also reflect upon the importance of interdisciplinary collaboration to account for the complex interaction of human and natural systems caused by increasingly extreme variation in the weather. Just as from culture to culture, we have a great deal to learn from each other, it is my belief that the bias towards singular solutions to defined problems is no longer adequate to cope with the multifarious challenges that our society is likely to be facing in the very near future. This leads me to the conclusion that a new paradigm for sympathetic partnership between professional communities will be more fit to embrace the essential continuity rather than separation between understanding cultural conditions and embedding them into logistical solutions
(This paper is a much-extended version of a presentation at the occasion of the Nordic Geographers Meeting in Tallin, Estonia 2015. The overall title of the series of sessions within which I spoke was “Imagining Wetlands: Geography between Wet and Dry.)
The shoreline and the community:
In spite of international treaties and agreements set up to guide the management of coastal and estuarine wetlands, such as the Ramsar Convention for Wetlands, the Water Directive Framework, and the European Habitats Directive, there are subtle variations upon their interpretation and application from one sovereign state to another. Anyone knows that so far as human usage is concerned, the value of land is the composite of the stories that animate it and that this is the product of particular cultural milieux. Memory and native conservatism combine to create the basis of a sense of ownership and responsibility for stakeholder communities, which, when underpinned by a political status quo makes some courses of action desirable and others out of the question.
England is undergoing a sea change in the governance of coastal and estuarine management policy, the implications of which have hardly been registered let alone accepted at a public level. Rightly or wrongly it appears that central government is gradually withdrawing from direct responsibility for the integrity of our coastline in favour of adopting a more mediatory role. Since it inevitably takes a while to see beyond misinformation and misunderstanding over who is responsible for what, there will be a delay in the time it takes for communities to overcome the sense of betrayal that their security is no longer automatically underwritten by a benign authority, to apprehend the potential for this be the first step towards a renaissance in public awareness and greater community autonomy. In turn this will inevitably evolve a very particular approach to coastal management, distinct from historical models and from the experience of other countries that must work with their own institutional constraints, freedoms and shibboleths.
Over at least the last ten years, the decision in England over whether land could be managed solely upon central government funding has been subject to a cost benefit analysis framework administered by the Environment Agency on behalf of DEFRA (Cost Benefit Analysis has been routinely used since 2005 as a tool for estimating whether a particular area vulnerable to loss through flooding or erosion might qualify for capital funding. This is subject to a calculation based upon the value of the area at risk against the amount it would cost to defend it. The standard for this was set at roughly a ration of 8:1. Recently this calculation has been modified somewhat to factor in the partnership principle, where alternative funding from a community source might draw in support from central government.)
Predictably this is a model that favours, people property and valuable infrastructure against agricultural land. It is equally predictable that landowners were not impressed and even felt let down and isolated by government. Over recent years government agency funding has been increasingly reduced to the point that only the most urgent estuarine and coastal projects can be exclusively paid for by the treasury. Elsewhere, especially in rural locations, partnership must be the name of the game. If this is taken in tandem with the Localism Act of 2011 (The Localism Act of 2011 was generated during the previous administration to cut red tape and to empower the citizenry by enshrining the principle of partnership.) and the devolution of greater power to communities, it could be considered an opportunity to reconfigure landscape according to their own priorities. In reality it also means that any shortfall of resource must be met through community engagement. However it is an ill wind that can blow good and on our rivers and coasts it has led to new approaches for essential defence works, for which central government funding would otherwise be unjustifiable. Starting as a protocol to facilitate the process for landowners to gain the necessary permissions to manage their own defences, this rapidly developed into a real partnership where initial private financial commitment could draw down support from other sources including national, regional and local government. Although to allow landowners to take the initiative is a workable principle where local interests are at stake and the resource is available, there is certain to be a level of doubt and obfuscation should this impinge upon broader interests or upon major national infrastructure projects where such largesse may not be so readily forthcoming.
Shorelines and the foreshore
The shoreline is where interests intersect, where the need for a sustainable coastal system frequently finds itself in conflict with local pressure to secure coastal settlements against their unviability from the effects of flood or erosion caused by increased storminess. Nowhere has this issue achieved such a high profile as it did in 2012 on the Eastern Seaboard of the United States after Hurricane Sandy, when opinion became starkly divided between those who wish to enhance the resilience of coastal defence works and coincidentally create further real estate investment opportunities on the shoreline and those who recommend withdrawal to allow the system to establish its own equilibrium. Predictably opinion is split between those who already occupy the coastal
fringe and intend staying put and those who do not. Although opinion has come down heavily on the side of enhancing shoreline resilience in one way or another, this disaster has had the effect of concentrating attention on an issue that until now has not been taken seriously enough and has at least raised the level of public awareness of the debate over climate change nationally even if consensus remains just as elusive as it ever was.
In February 2012, whilst participating in the AGM of the Association of American Geographers in New York, I joined a field trip to Long Island Beach. It was a week of spectacular skies and strong winds. When we arrived at the coast there were massive storm heads developing offshore and onshore a full-blown sandstorm was raging through the coastal dunes. At the time I remarked upon the comparative openness of the beach and the limited evidence of coastal management. Our two
guides, being both geography PhD students and very keen surfers, explained that this rather ambivalent approach to beach stabilization was part due to a conflict of interest through the use of the beach for the Annual Surf Championships, where the presence of too many hard groyne structures would not only have compromised the wave systems as they approach the near shore, but also constitute an unacceptable hazard for the participants. Beneath the boardwalk at the top of the beach, there is a seawall, which, at the time of my visit provided direct access to the beach through regular apertures with no apparent floodgate provision. The landward side of the wall is lined with condominiums all of which open on to the street at a ground level lower than the beach in front of the wall. The main street running parallel to the beach still has some older more modest houses, many of which significantly are sited upon low pyramidal mounds. When I queried the absence of precautionary measures against storm driven surge tides, the answer was that this part of the coast has nothing like the tidal range that we experience on the East Coast of the UK and that the tide never even reaches the top of the beach. Correspondingly the main focus of environmental effort has been to give preference to a strategy to anchor the unstable dune system over safeguarding against potential flood events.
Within 8 months this all changed when, on 29th October 2012, Hurricane Sandy made its landfall and the question of coastal management and flood resilience for the entire East Coast was put into complete disarray with repercussions that would be felt nationwide. Overnight those unstable dune systems were swept aside and dumped inland, shoreline structures such as the famous boardwalk were shredded, weatherboard houses lost their foothold or succumbed to the relentless battering from seas for which there could be no possible resistance.
In Suffolk, UK, where I have my home on the River Deben Estuary, there is a continuing debate about flood risk management of quite a different order.
Although the expectations are also that the sea must remain where it should, on the wet side of the sea walls, the East Coast of England is no fools paradise;
preparedness has been hard won from bitter experience of loss of life, livelihood and property within many peoples lifetime: the disastrous tidal surge of 1953, breached many of the coastal defences of East Anglia as well as much of the Dutch Coast with a combined death toll that was numbered in thousands.
In East Anglia, the immediate response to a very poor level of emergency preparedness was to beef up the sea walls around the entire coast and bring them to a consistent standard. Since that time, whilst the overall coastal defence strategy has become increasingly well coordinated, conditions have changed: many of the hard defences, put in place in the 1950’s are now failing due partly to their age but also to a fundamental flaw in the principle of the defences themselves. Hard concrete structures may stop the sea from getting in but they also deprive coastlines of mobility and with this the capability to accrete and retreat according to the vagaries of weather and sediment transport. In this sense they hold the seeds of their own destruction.
The River Deben is predominantly a rural estuary with just one major settlement, Woodbridge, at the head of navigation. Consequently, most of the flood defence walls along its length are of clay construction and frequently ancient enough in their origin to be established upon medieval foundations. As for most of the rivers in Suffolk, in front of many of the walls there is a fringe of saltmarsh, which acts as a first line of defence and bears the brunt of wave action and tidal energy. This is a relic of those more extensive marshes historically ‘warped in’ to create productive farmland. Under the aegis of the Deben Estuary Partnership, formed in 2009, a campaign has been undertaken to bring all of these walls up to a consistent standard, of which, one particular project was for a turf wall where the tidal Martlesham Creek enters the River Deben estuary at Hill Farm. This task, undertaken through a partnership agreement between the landowner, the local authority, Suffolk County Council, the East Suffolk Internal Drainage Board and the Environment Agency, was completed in 2011.
Although this was a positive step and considered a great success at the time, on 6th December 2013 the East Coast of England experienced a surge tide that was equal to if not exceeding the levels of the 1953 disaster. Fortunately, because our level of preparedness is now much improved, there were no fatalities but there were several incidences of failure of defence works, including those that had been constructed on Hill Farm just two years previously. This wall breached in three locations each as a result of overtopping and eroding the back surface to the point that it was sufficiently weakened to the point of collapse and, unable to withstand the sheer weight of water, bursting spectacularly, dumping complete sections well inside the field and leaving them behind after the tide has ebbed.
Reject the inevitable and advance the shoreline:
On the eastern seaboard of the United States, post Hurricane Sandy and after the immediate recovery and adaptation process, the priority was to develop a suitable long-term approach to coastal vulnerability. This took the form of an international call for engineering solutions, where the submissions ranged from reinstating natural intertidal resilience and withdrawing settlement where it is considered unfeasible, to beefing up the hard defences on the assumption of business as usual. Unsurprisingly the strongest arguments were to underpin if not enhance the value of beachfront real estate and to turn emergency into opportunity. If the commitment is so great to retain coastal developments that there can be no retreat, the only alternative is to find ways to advance the shoreline. A scheme for the exposed shoreline of Staten Island that was the winner of the Buckminster Fuller Prize in 2014 was “Living Breakwaters”, by ‘Scape’ Landscape Architects. This comprises a series of cellular concrete reef structures placed in the immediate offshore littoral zone to promote marine biodiversity and develop a native Oyster habitat. The intention would be for these new Oyster Reefs to create sufficient shelter to propogate biodiversity and act as breakwaters to attenuate wave action. The long-term strategy would be to develop a chain of reefs and islands to provide a new marine environment and remove a degree of risk of storm damage to onshore settlements. A similar approach is in the development process for the San Francisco Bay area; this is a concept called “Horizontal Levees”, very much in the spirit of “Living Breakwaters”1 this also aims to keep the shoreline exactly where it is by extending a vegetated intertidal zone seaward to attenuate wave energy and absorb the impact of storm driven seas, thereby reducing the level of flood risk for the immediate coastal environment. Both of these examples appear to be driven by the single principle to retain the viability of coastal communities and the value of shoreline property as an investment and rely upon the principle of constructing a way out of crisis.
Accept and exploit the inevitable:
In the Netherlands, the need to live with continuous threat has prompted other solutions informed as much by a culture wedded to the water as by native pragmatism. The precarious relationship that they have with the sea is in the DNA of the Dutch, their livelihoods and way of life has been won from the sea, which could if the guard were allowed to slip, take it all back again. At present the Dutch are being tested again; as always their land is under threat, but now unpredicted hazards have arisen, directly and indirectly the result of the original great polder experiment. As land is drained, so over time it shrinks. An indication of the age of reclaimed territory is the amount it is below sea level, the older the polder, the lower its elevation.
- So long as the protection stays in place, this would normally not be a problem, but due to increased storminess and seasonally high rainfall the threat can shift inland to the fluvial system and the inability of rivers to cope with increased flows, leading to higher incidence of flooding. Where this has happened the Dutch have responded with typical pragmatism: for areas of high risk there is an initiative called “Making Room for the River”, which is to create flood holding areas to contain excess fluvial water at times of spate or to increase the capacity of the existing river channels and to create flood relief channels such as is currently being engineered for the River Waal at Nijmegen.
- Even where a polder is secure from flooding another effect is being felt, which is salt percolation from the sea, corrupting the fresh water supply and salinating the soils to such an extent that orthodox arable cultivation threatens to become unviable. As a response to this, a successful project to develop a salt tolerant variety of potato has been conducted on the island of Texel in the Netherlands. This has been such a success that now seed potatoes are being exported to Pakistan to be trialed on salt contaminated land there.
- Just as in the USA, hard coastal protection in the Netherlands is an impediment to sediment transport with the effect that beaches become depleted, exposing defence works directly to the effects of increasingly volatile weather and violent storms. Directly offshore at Ter Heijde on the Delftland Coast a project to supplement sediment drift is being trialed: instead of recharging beaches directly to bring them up to level, the principle is to deposit very large amounts of sand in strategic locations on the coast and let longshore drift do the rest. This “sand engine” initiative has attracted a great deal of attention internationally, not the least on our soft East Anglian Coast where it is increasingly difficult to justify extraneous hard structures, and has become a dilemma to know what to do for the best to promote coastal stability into the future.
For the UK
In keeping with an awareness of the diversity of coastal topography, influenced by local landscape characteristics and levels of vulnerability, there is a more nuanced approach towards management. Where sea defences experience high level of stress, depending upon an assessment of the level of risk and loss of assets, there may be strong arguments for letting them go in a controlled manner and withdrawing to create new intertidal zones through managed realignment. This is a sensitive issue and Central Government through the Environment Agency has learned to become informed of local opinion and interests before advocating a particular course of action. Consequently, in order to secure a dedicated solution, local influence exerts a greater pressure upon the decision making process.
Bow to the inevitable- Palliative Management:
where it is clear that in the long term there will be no choice but to accept that a defence will sooner or later fail, the best option might be to bow to the inevitable, put mitigation measures in place and withdraw gracefully1. A good example of this is Abereiddi on the Pembrokeshire Coast: owned by the National Trust, it became increasingly obvious that the protection measures put in place against coastal erosion had incrementally become so brutal as to impact negatively upon both the environmental integrity of the site and the visitor experience, with the effect that the most sensible solution became to remove the hard defences altogether and let the coast realign and stabilize in its own manner.
This approach chimes with the stated aims of the National Trust to, wherever possible, allow natural processes to generate their own equilibrium so long as due regard is paid to the need to secure the immediate community against a higher level of risk.
“Tinkering around the edges”:
this was a comment made by a local coastal officer, upon the inclination of communities to tackle the symptoms of environmental change upon our coast and estuaries in a piecemeal, case-by-case manner, rather than respond strategically to a perceived cause. Although this criticism makes perfect sense, it does not acknowledge the need for communities to develop a sense of ownership and responsibility for their own landscapes. There is scope for both major, whole landscape, capital works such as the Wallasea Island realignment site on the River Crouch in Essex and modest projects that foster a sense of social engagement and understanding of the natural systems at work and which incrementally work by stealth towards a major shift in the strategy for managing our coastal landscapes.
“Tinkering” does not necessarily limit itself to modest lo-tech projects; it can be extremely ambitious, when, for example, overriding stakeholder interests coupled with the determination to meet the challenges head on, prompt communities to take matters into their own hands. The difference between these projects and comprehensive strategies is that they tend to be one off and conceived in isolation with scant regard for the effect that they might have upon the behavior of a whole system. Even with best engineering support and advice, they can be a step into the unknown where unforeseen consequences can happen and permanent solutions remain elusive.