A review of the Deben Estuary Plan

Over the past five years the Deben Estuary Plan has informed planning and management decisions on the River Deben estuary. Much has changed, even over this short period, and the Deben Estuary Partnership is now embarking on a revision process to identify challenges faced on the estuary today and to bring the estuary plan up to date.

It is gratifying to report that much of what was set out in the Estuary Plan of 2015 has been accomplished:

  • All of the flood defence walls have been brought up to a consistent standard with the exception of Flood Cell 1, which is currently under negotiation
  • The value of saltmarsh has been acknowledged, as intertidal habitat and as a vital component of flood management, and an ongoing programme for managing those sites that lend themselves to remediation has been established.
  • From a survey of what visitors and residents value most about the estuary, tranquillity has rated very highly. This has since become enshrined as a key element in the planning guidance.
  • Although the Estuary Plan has been endorsed by the Local Planning Department, the County Council and, importantly, the Environment Agency, and has the status of “material guidance”, this represents a shortfall in the status of the plan that will be necessary to address in its new iteration.

The revised plan:

Whilst some factors such as flood risk management and ensuring that the special estuarine habitat is conserved must continue, there are changes and new demands that must be factored into our planning for the future. For this reason, accommodating and adapting to changing circumstances will be key to our considerations in bringing the estuary plan up to date.

  • Although the Bawdsey coastal frontage does not fall within the boundary of the present Estuary Plan, the increased rate of coastal erosion and substantial loss of beach material may have an impact on the integrity of the knolls and the natural protection that they give to the estuary mouth. Taken with the imminent need to address the vulnerability and condition of the sheet piling, both on the seaward and estuary frontage below Bawdsey Manor, this will be an issue demanding an integrated and strategic response over the coming years.
  • The demands made upon the estuary, ranging from infrastructural to housing and tourism, are putting pressure upon its unique biodiverse environment. Given increased pressure for housing development in the region, Deben Estuary Partnership is increasingly aware that more attention needs to be given to planning guidance for the estuary envelope, and specifically, the wider estuary floodplain. Developments across this broader zone may have negative impact upon the estuary landscape, which would be detrimental to the integrity of the intertidal zone and compromise flood risk management. attention needs to be given to the planning guidance for the estuary envelope, and specifically, the area within the estuary floodplain.
  • Climate change and sea level rise were considered when the present Estuary Plan was prepared, but it is clear that changing conditions are beginning to have a more obvious impact upon estuary processes and livelihoods. Due to the increased frequency of storms and accompanying surge tide events, the resilience of our flood defence walls has been severely tested. It has become clear that fringing saltmarsh has a role to play as a primary flood defence, reducing wave energy, thereby decreasing the potential erosion risk to the flood walls during high tides and surge events. However, the saltmarsh itself is beginning to show signs of stress, partly due to water quality issues, and partly due to stress caused by the acceleration of sea level rise.
  • Seasonal shifts of higher winter rainfall followed by prolonged periods of drought have heightened the need to increase the capacity to retain surface water and store it against demand for irrigation during the summer months. With this in mind, significant amongst individual reservoir projects under development in the region is the ongoing “Felixstowe Hydro” scheme to redistribute and store water draining from the Colneis Peninsula. Essentially this will mean that the sluice at Falkenham will no longer be a major outfall, and water will be pumped back and either stored or used to recharge the aquifer.
  • Since 2015, the offshore energy installation, Anglia 1 has come onstream, the cable landfall is at Bawdsey and is being laid beneath the Deben at Flood Cells 1 and 7 and crossing again at Martlesham Creek. It is anticipated that since the landfall for the cables is on an eroding coast, there will be an ongoing need to monitor and maintain it.
  • The route of the National Coast Path remains an unresolved issue. For the Deben there are reservations that include locating a path along the rapidly eroding and hazardous coast at Bawdsey and establishing a new path between Bawdsey and Ramsholt, which would cause disturbance to rare birds and saltmarsh habitat at Bawdsey. The alternative proposal is to use the foot ferry instead of negotiating access around the entire estuary. The context for this discussion is the inevitable increase in disturbance that greater access would promote and the loss of valued tranquillity set out in the 2015 Estuary Plan.
  • Since the publication of the current estuary plan, there have been a significant number of research projects conducted on the Deben. Much of this was carried out between 2018-2020 under the auspices of the Suffolk Marine Pioneer, which was set up to explore ways in which the government 25 year environment plan might be implemented. Other projects were commissioned on an ad hoc basis to augment the knowledge base on the Deben Estuary. The review of the Estuary Plan will be an opportunity to assess the applicability of the data gathered to the generation and implementation of policy.
  • Over recent years, the use of new criteria to calculate the value of the natural environment have come into play, which enables a cost-benefit analysis for the maintenance of any natural asset. Natural Capital is the term to describe our stock of natural assets including geology, soil, air, water, and all living things, from which society derives services known as ecosystem services: once defined these can lend themselves to a cost benefit calculation. Whilst as a tool this is still very much under development, the certainty is that the principle will hold the key for developing future funding models.

The new Suffolk Coastal Local Plan, under which the Deben Estuary Plan sits, has been delayed, and correspondingly the formal start of the consultation process for a revised estuary plan is also pending. It is expected that progress will be made on this from autumn 2020, and it is anticipated that the estuary plan will be finally published early 2022.