Although the Pevensey Bay Sea Defence project exists to maintain a 9km long shingle embankment, it is classified as an environmental scheme, and as such has always had environmental awareness at the forefront of all activities. Very early in the 25 year project, we recognised that the best way to maintain the beach, reduce risk of further erosion, and protect neighbouring properties was to set out a sustainable strategy for construction and maintenance of the embankment. Sustaining the beach in order to protect local communities and the surrounding environment inherently embraces the concept of sustainable development. However, it has only been more recently that the concept of overall sustainability has begun to replace a purely environmental view.
The project has had an Environmental Management Plan in place since it started in 2000, but by 2011 it was time to formalise a sustainability policy by means of a Sustainability Action Plan. Along with many others, we have used the definition of ‘sustainable development’ to be that included in the 1987 Bruntland Report as;
In order to present a balanced approach, the plan considers equally the “three pillars" of sustainability;
By 2012, we had been able to apply innovative techniques to management of the defences and in doing so helped develop evolution of best practice. Lessons learnt and are now being used to good advantage on site, and are starting to be used elsewhere. Over the remaining years, we recognise the need to continue to respond to wider sustainability challenges and opportunities that arise. To do so requires a fully integrated approach to managing social, environmental, community, ethical and broader economic factors. Therefore this plan not only confirms our commitment to sustainability but also outlines a series of targets and actions under each of the three key sustainability strands. In its preparation it has been reviewed and aligned to the economic, social and environmental commitments of our shareholders and our client, the Environment Agency. It remains a living document and hence must respond to changes that occur, both in our own operations and in the needs of our stakeholder’s organisations, each of which has a special interest in the project area.
Whilst we seek the views of stakeholders on a regular basis, we welcome equally those of individuals and other groups. There are several ways for individuals or organisations to voice their views;
Management of a shingle beach does not present many opportunities to improve sustainability since the number of materials involved is small;
Dredging operations have changed little in recent years and given the shallow nature of English Channel coasts there is little option but to use dredgers like Sosopan Dau, which is an extremely efficient vessel. By fitting a bulbous bow, the dredger has been able to reduce fuel costs by around 8%. New engines were installed in August this year. These replaced 13 year old ones and have introduced further benefits just by being new and more efficient.
Although fuel savings can be clearly demonstrated by the dredger, this is not the case with machines on the beach. Being a particularly harsh environment, the life span of each machine is not especially long. Each new model that is developed does introduce fuel saving efficiencies and generally increased carrying capacity. However, work on the beach changes day to day so that the amount of shingle moved, the distance it has to be carried and the type of surface trucks are running on, all vary all the time. It is much cheaper to move shingle a short distance - say 500m - than it is 3km from Cooden to Normans Bay for instance. Thus, at the end of each winter, we calculate how much CO2 has been produced against how much shingle has been moved. Invariably no pattern of improvement emerges, because the distance moved is never constant.
Tropical hardwoods have been the favoured timber source for many years because of their durability. But, they are dense and thus resilient, because they take so long to reach maturity. Hence, most are now seen by many as an un-sustainable material. With this in mind, much of a two-tiered timber wall built at Herbrand Walk in 2002 used Douglas Fir, a faster-growing but last durable soft wood. Being on the landward side of the sea defences, it was not subject to abrasion from wave and shingle movement. It did however rot, because it rarely - if ever- completely dried out.
In the meantime, significant progress has been made in the re-use of household waste and other plastics. Previous experiments with plastic planks (as shown here) had shown promise, but it has only been in the last year or two that planks of sufficient size and strength have been produced. As a result, the majority of the planking at Herbrand Walk was replaced by recycled plastic in July and August, saving around 17 cibic metres of hardwood, or about 1km length of wooden planks. Not only is this a more sustainable solution, because it uses a waste product, it will also last indefinitely.
The new plastic planks at Herbrand Walk along side remaining Douglas Fir
Pevensey Coastal Defence Ltd, Westminster House, Crompton Way, Segensworth West, Fareham, Hampshire, PO15 5SS
Registered in England, Company No. 03776520