64 state of the 8. HYDROGRAPHICAL CONDITIONS

Key Messages • A substantial proportion of the Northern Why are hydrographical conditions altered? coastline has been altered by coastal This chapter examines the way in which defence structures. This is particularly our coastal zone has been altered by man’s prevalent on soft coastlines. Its extent is activities. estimated to be approximately 100 kilometres. • There is a need to establish an accurate Many of these changes can have a permanent baseline of the nature and extent of coastal effect on , and currents, and can defence structures. In many places, coastal be considered collectively as ‘hydrographic defences protect reclaimed land and open conditions’. The main factors that have spaces as well as buildings and roads. permanently altered our line and • needs a strategic approach therefore the hydrographic conditions are; to shoreline management rather than , flood protection, reclamation, an ad-hoc approach. The need for this is recreation and development. Renewable increasingly apparent given the onset of energy is likely to be a future pressure that rising levels. needs to be considered. • Public awareness needs to be raised in relation to the impacts of coastal defences In what ways have hydrographical and the legal situation regarding building conditions been altered around our coast? and maintaining coastal defences. Sea / flood defences • The response to climate change and sea Protection of infrastructure by sea defences is level may involve abandoning, maintaining widespread in Northern Ireland. Many major or extending the current defences. An access roads and associated infrastructure integrated approach to this issue is needed follow the coast. Their position makes them because of its impact on a diverse range of vulnerable to periodic erosion and flooding and interests including housing, conservation, the Roads Service seeks to minimise these transport, tourism and recreation. risks, chiefly by constructing sea defences. In • Artificial shorelines typically have lower parts, the railway line impinges on the coast biodiversity than their natural counterparts. and those stretches are managed by Translink. hydrographical conditions 65

Many public and privately owned properties Land reclamation threatened, or believed to be threatened, have There is a legacy of the ‘reclamation’ of been protected with various types of coastal intertidal land for agriculture and for defence structure. construction. During 19th century, much of the intertidal area of the sea loughs and estuaries The Agency is responsible for were lost. Infill of Lough formed the maintaining several stretches of ‘statutory inner port area and also provided a convenient flood defences’ along the coast including the site for disposal of waste, a practice which has major sea defence structures at only ceased in the last decade. These areas and in Lough Foyle. However there are only are defended by a variety of embankments 36 kilometres of statutory sea defences. and rock armouring in various states of repair. Two tidal barrages on the Lagan and Quoile Commissioners recently estuaries provide flood protection to Belfast reclaimed a major new area within the port and . creating a new berth for the Stena ferry.

Navigation Recreation The need for safe navigation in our ports and Recreation and tourism are increasingly harbours imposes maintenance obligations on important to society. Historically, several our harbour authorities. In order to maintain promenades were constructed to facilitate easy shipping channels at the depths shown on access along the coast. These continue to be navigation charts, harbour authorities have a maintained and altered as they are regarded as duty to dredge within harbours. In addition important elements of tourism. to maintenance dredging, occasionally ports In addition, coastal paths are defended in carry out capital dredging work where virgin places with various forms of armouring. The material is removed to create deeper channels coast is seen as a desirable place to live. for bigger with a deeper draft. Dredged In recent decades there has been a major material of acceptable quality is disposed of at phase of intensive coastal development with licensed disposal sites around the coast. These apartments replacing single dwelling units sites are accepted as sacrificial areas where and construction of new buildings outside material of an acceptable quality may be taken the existing urban footprint. A number of from and returned to the sea in order to keep coastal developments have been accompanied our ports and harbours open. Existing disposal by marina construction, for example, at sites are shown in Figure 8.1. and Bangor.

Marine Renewable Energy In recent years, renewable energy has become an emerging issue and is likely to increase as a pressure in the future. The pilot tidal turbine in Lough is currently the only installation but the Department of Enterprise, Trade and Investment (DETI) has a duty to increase our use of renewable energy and Northern Ireland has a rich resource in both wind and tidal energy (Figure 1.4).

What impact do these alterations make to the marine environment? Many of the features and activities described

© British Crown and SeaZone Solutions Limited. All rights reserved. Products License number 122008.006 above, including sea defences, impoundments, coastal paths, dredging and reclamation will Figure 8.1 Dredged material disposal site locations remove intertidal habitats. In some instances, licensed under the Food and Environment Protection Act. new habitats are formed like coastal lagoons 66 state of the seas

Millisle, Co

(e.g. , Anne’s Point) or the brackish , harbours and training walls all alter at the Quoile Pondage. These new the patterns of movement and therefore habitats can be unique in character and can affect the patterns of erosion and deposition. become important wildlife reserves. is a good example where construction of a small pier at the western Dredging has direct impacts on the organisms side of the bay focused wave action and led living in the sediment and on sedimentation to erosion of the beach. This in turn led to patterns at the dredging and disposal sites. increased wave attack on the soft cliffs behind It can also alter circulation, tidal patterns and the beach which was addressed by a scheme water chemistry. of dewatering and stabilisation of the cliffs and construction of sea defences. More recently, Weirs remove much of the tidal variation in the sea defences have been extended and a water level and may mean that some habitats series of groynes emplaced to try to trap sand are now permanently submerged, circulation is in the bay. modified and the may be changed. Seawalls and rock armour have both direct and Land claim directly removes intertidal habitat. indirect effects. They cause loss of habitat over Significant areas of intertidal habitat have been the area they occupy. The seawall fronting the lost in all of the sea loughs. Reclamation also Newcastle Centre, for example, occupies a reduces the tidal prism of coastal water bodies. substantial area of former beach. This prevents This means that less water flows in and out, waves dissipating their energy through erosion tidal currents change and if there are sediment and breaking. Instead the waves are reflected deposits at the estuary mouth they may change back to sea. This can cause greater turbulence shape by erosion and accretion. This is most in adjacent sand and mud habitats and promote likely to happen in areas like Dundrum Bay and erosion of the remaining sand or mud. These Lough Foyle which have mobile sand banks at structures can also reduce sediment supply their inlets. that would formerly have existed through the erosion of soft sediments or sand dunes. hydrographical conditions 67

Coastal reinforcement,

On the outer peninsula there are many example, are different to natural cliffs and rock raised beaches. They contain sand that under armour is different to sand dunes or soft cliff natural conditions would sustain modern habitat. There are few studies on the relative beaches as they are eroded. Coastal defences biodiversity of artificial and natural shorelines have now cut off that supply. Seawalls on but those that have been carried out indicate beach-dune systems cut the link between lower biodiversity on artificial shorelines the two and destroy the natural sedimentary compared to their natural counterparts. system. At a time of rising sea levels, coastal defences prevent the landward migration that How are these alterations regulated? would otherwise occur, thus intertidal habitats New deposits in the sea, like construction (beaches, tidal flats and salt marshes) become works, land reclamation or the disposal of steeper and are eventually ‘squeezed out’. dredged material are controlled by a licensing In Strangford Lough, a National Trust report system under the Food and Environment concluded that 50% of the tidal flat could be Protection Act. The licensing authority is NIEA lost by coastal squeeze during rise(1). and the system operates from the mean Furthermore, the reduction in sediment supply high water spring out to the limit of our may alter the sedimentary system both in the territorial (12 nautical miles). Existing immediate area and alongshore. structures like sea defences are exempted from requiring a new licence. However, major Hard coastal defences lack the flexibility of upgrade projects are subject to environmental natural defences, like beaches and dunes, controls. that can change shape to accommodate storm waves and then recover after the storm The licensing system seeks to ensure that has passed. Hard defences require constant construction or disposal works have a minimal maintenance and can fail, as in the case of the impact on the marine environment. This is Slieve Donard Hotel seawall in February 2002. achieved largely through mitigation measures, such as restrictions in the times of year, or the All types of solid structures in the coastal zone requirement that suspended solids are limited create artificial habitats. Harbour walls, for through monitoring. 68 state of the seas

The EC Water Framework Directive recognises In parts of the Plain around , that altering the physical regime in the coastal for example, defences have been put in place zone has the potential to adversely impact to support a footpath. Elsewhere individual the ecology. It requires an assessment to be stretches of armour have been used to protect made of hydromorphological (shape and flow) roads, private property (houses, gardens and alterations to ensure these do not compromise farmland) and public land (including buildings, the ecology. However the Water Framework parkland and car parks). On the north coast, Directive recognises that in certain areas, like armour is mainly confined to resort beaches ports, modifications are inescapable to allow at and Portballintrae. Four kilometres necessary commercial activities. The Directive of coast are identified as being fronted by allows these areas to be designated as heavily groynes at Newcastle (where they are in modified and for alternative objectives to be set disrepair), Ballyholme and Portballintrae. in these areas. For example, a normal sediment Training walls fix the position of the channel at biology will not be expected in a dredged the mouth of the Bann. Field examination channel. of the coast suggests that these figures are underestimated, as many small areas of How have these alterations been armouring have not been mapped. monitored? As part of the implementation of the Water Harbours, quays and jetties are present at Framework Directive, NIEA needed to numerous locations around the coast and vary understand how much of the coastline had in scale from major systems of quays and been modified. The distribution of coastal wharfs to small harbours and slipways. structures, where hydrodynamic conditions are altered, was derived from visual classification What is needed in the future? using a series of oblique aerial photographs. Under existing arrangements, the approach to In this exercise, various types of structure were managing alterations of hydrographic conditions mapped including seawalls, rock armour, ‘piled is piecemeal. This has been highlighted in structures’, groynes, training walls and marinas. a recent report by DARD Rivers Agency(2). This method was useful in deriving approximate Responsibility for coastal defences is split lengths of modified coastline. There are, between Government Departments, with however, several areas where the photography DARD having a statutory responsibility for was not sufficiently detailed to enable coastal some sea defences and DRD being responsible defences to be recognised or categorised. It for protecting road and rail infrastructure. is estimated that seawalls and rock armour cover 55 and 22 kilometres of our coast, Elsewhere, responsibility for coastal defences respectively. ‘Piled structures’ are present on 7 is based on the ‘Bateman formula’ which kilometres and ‘breakwaters’ are present on a assigns responsibility to various Government further 7 kilometres. These areas of armoured Departments in a poorly defined way. Unlike coast include significant stretches in the upper the situation in England and Wales, there reaches of , inner Dundrum are currently no plans for Northern Ireland Bay, Strangford Lough, Lough, Belfast that permit a strategic approach to shoreline Lough and Lough Foyle. In many instances the management. defences protect reclaimed land. Food and Environment Protection Act licences On the open coast, coastal defences are are currently determined on an individual basis present along much of the areas that are not with no overview as to how a construction in composed of solid rock (i.e. beaches and soft one area will impact on another area. A new cliffs). Substantial areas are armoured along licensing system is due to be introduced in April the southern part of the Mourne Plain from 2011 under the UK Marine and Coastal Access Annalong to Cranfield, around Newcastle, on Act and the proposed Northern Ireland Marine the outer and along the Antrim Bill will introduce marine planning by 2014. Coast Road. hydrographical conditions 69

This will enable cumulative impacts to be reach sources of sediment previously outside considered. However, more information is the limit of wave action. required on the movement of sediments around our coastline both now and into the Areas of sand dune, raised beach and glacial future. This is needed to inform a strategic sediments are particularly important sediment approach to managing physical changes to our sources in this regard and they will be coastline. needed to maintain the coastal habitats and ecosystems. Further work is required in this Sea level is projected to rise in the coming area to inform good management and licensing years and this will have major implications. As decisions. the sea encroaches further on the land it will

Legislation Marine Framework Strategy Directive Descriptor 7 Permanent alteration of hydrographical conditions does not adversely affect marine ecosystems Other relevant EC Directives (full references and corresponding regulations – Appendix II) Driving overall improvements in incorporating Water Framework Directive hydromorphological changes in estuarine and coastal waters To protect, maintain and restore natural habitats and species of European Habitats Directive importance, in favourable conservation status International Agreements OSPAR Convention for the protection of the marine environment of the Biodiversity and ecosystems strategy North-East Atlantic Local legislation This allows NIEA to regulate deposits like dredged material or construction Food and Environment Protection Act, works in the sea. The licensing process can set conditions to ensure that (1985) Part II environmental damage is limited in marine construction projects. New marine licensing legislation is due to be introduced in April 2011 The Drainage (Northern Ireland) Order Giving Rivers Agency, an Executive Agency of DARD, a duty to maintain 1973 statutory sea defences

References (1) The National Trust 2007 Shifting Shores – living with a changing coastline.

(2) DARD Rivers Agency 2009 Living with Rivers and the Sea.