coastal trends report - channel coast … · longshore drift of beach material dominates much of...

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Coastal Trends Report Suffolk

RP022/S/2011

February 2011

(Lowestoft to Languard Point, Felixstowe)

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We are the Environment Agency. We protect and improve the environment and make it a better place for people and wildlife. We operate at the place where environmental change has its greatest impact on people’s lives. We reduce the risks to people and properties from flooding; make sure there is enough water for people and wildlife; protect and improve air, land and water quality and apply the environmental standards within which industry can operate. Acting to reduce climate change and helping people and wildlife adapt to its consequences are at the heart of all that we do. We cannot do this alone. We work closely with a wide range of partners including government, business, local authorities, other agencies, civil society groups and the communities we serve.

Published by:

Shoreline Management Group Environment Agency Kingfisher House, Goldhay Way Orton goldhay, Peterborough PE2 5ZR Email: [email protected] www.environment-agency.gov.uk © Environment Agency 2011 All rights reserved. This document may be reproduced with prior permission of the Environment Agency.

Further copies of this report are available from our publications catalogue: http://publications.environment-agency.gov.uk or our National Customer Contact Centre: T: 03708 506506

Email: [email protected].

http://publications.environment-agency.gov.uk/

mailto:[email protected]

Easton Marshes (Photo: Environment Agency)

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Glossary Accretion The accumulation of sediment on a beach by the action of

natural forces or as a result of artificial structures Bathymetry The topographic relief of the seabed Beach recharge Artificial process of replenishing a beach with material from

another source Berm crest Ridge of sand or gravel deposited by wave action on the

shore just above the normal high water mark Coastal Squeeze The reduction in habitat area that can arise if the natural

landward migration of a habitat under sea level rise is prevented by the fixing of the high water mark, e.g. a sea wall

Erosion The loss of material from a beach by the action of natural

forces or the result of man-made artificial structures interfering with coastal processes

FCP Foreshore Change Parameter – a score of foreshore

steepening or flattening Foreshore The area of beach lying between high water and low water Foreshore rotation Foreshore steepening or flattening resulting in the

convergence or divergence of high and low water marks Groyne Shore protection structure built perpendicular to the shore;

designed to trap sediment Longshore drift Movement of sediment along the shoreline MHWS level of Mean High Water Spring tides MLWS level of Mean Low Water Spring tides MSL Mean Sea Level Ness A large low-lying foreland or promontory of mobile sands or

shingles attached to the foreshore SANDS Shoreline and Nearshore Database - software developed by

Halcrow for the analysis of beach profile data SMP Shoreline Management Plan. A high level strategy plan for

managing flood and erosion risk for a particular stretch of coastline

Soft defences Engineering options which are non-rigid (like sea walls) and

which work with the natural coastal processes of wave action and sediment movement

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Suffolk Coastal Trends Analysis

1.0 INTRODUCTION.................................................................................................................... 1 1.1 COASTAL MONITORING ...................................................................................................... 1 1.2 ANALYSIS METHODOLOGY ................................................................................................ 1 2.0 STUDY AREA ....................................................................................................................... 3 3.0 ANALYSIS............................................................................................................................. 6 3.1 OUTLINE TIDAL OBSERVATIONS ....................................................................................... 6 3.2 DETAILED OBSERVATIONS ................................................................................................ 8 3.2.1 Lowestoft to Kessingland ...................................................................................... 8 3.2.2 Kessingland to Southwold ..................................................................................... 9 3.2.3 Walberswick to Dunwich ..................................................................................... 11 3.2.4 Dunwich Heath to Thorpeness ............................................................................ 11 3.2.5 Thorpeness to Orfordness Lighthouse ................................................................ 11 3.2.6 Southern Orfordness ........................................................................................... 13 3.2.7 Shingle Street to Bawdsey Manor ....................................................................... 14 3.2.8 Felixstowe Ferry to Landguard Point................................................................... 15 3.3 TRENDS ANALYSIS MAPS.......................................................................................... 16 - 35 Appendix 1 – DETAILED RESULTS .................................................................................................... 36 Appendix 2 – REFERENCES............................................................................................................... 39

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Map 1 – Shoreline Management Plan 2 boundaries (2011)

copyright and/or database rights 2011. All rights reserved.© Crown copyright and database rights 2011 Ordnance Survey 100024198. © Environment Agency

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1.0 Introduction

1.1 Coastal Monitoring The Shoreline Management Group (SMG) based within the Environment Agency’s (Anglian Region) Flood and Coastal Risk Management section has undertaken regular strategic coastal monitoring of the Anglian coast since 1991. The Anglian Coastal Monitoring programme is now coming to the end of its phase VII (2006/07 to 2010/11) programme which has collected a variety of data including; • Annual aerial photographs • Bi-annual strategic topographic beach surveys (winter and summer) at 1km intervals • Bathymetric surveys (extension of beach survey lines out to approximately 10m depth offshore) • Continuous wave and tide recording (nearshore and offshore). As part of Phase VII this included

a suite of five offshore, and twenty nearshore continuous wave and tide recorders. • Scheme specific beach topographic surveys at closer intervals Beach topographic profiles have been undertaken at 1km intervals, twice yearly in summer and in winter, along the coast since 1991. Generally speaking the main aspect of interest is the average rate of beach erosion or accretion along the coast. In addition to this, gradual change to the gradient or steepness of the beach is often of particular interest to coastal managers. The positional accuracy of the Anglian Coastal Monitoring profiles is +/-0.05m vertical and +/-0.02m horizontal. Now, with a continuous record of nearly twenty years of beach topographic data, it is therefore possible to analyse these to determine reasonably robust initial indicators of longer-term trends and the Shoreline Management Group have produced a number of Coastal Trends Reports for Anglian region which tie in with the Shoreline Management Plan boundaries (see Map 1). This report is an updated version of the Suffolk Coastal Trends (2007) analysis, now incorporating data up to and including summer 2010 with trends recalculated to reflect this new data. Our scheme specific monitoring addresses more local sea defence scheme requirements in greater detail at a variety of locations along the coast. More in-depth analysis at key locations such as at Southwold to Benacre and at East Lane, Bawdsey has taken place. These reports often analyse more of the beach profile, for example above high water using in-house software and incorporates the use of historic OS maps. These reports are also available from the SMG with more key area analyses being undertaken as and when required. The new Phase VIII monitoring commencing in April 2011 and running to 2016 will link with the national coastal monitoring programme providing improved levels and intensities of topographic and bathymetric data. There will also be more emphasis on habitat monitoring through aerial and LiDAR survey.

1.2 Analysis methodology The profile data presented in this report is mainly in the form of tide level analysis and movement of the foreshore between high and low water together with aerial photography between 1991 and 2010. Tide level analysis and the temporal changes to the beach foreshore and gradient looks at the corresponding lateral movement of the high and lower water marks over time. This data was analysed using a function of ‘SANDS’ software with tidal parameters, derived from harmonic analysis, supplied by Gardline Environmental Ltd. The foreshore represents the intertidal region between the highest and lowest tide level and in this report the area between the MHWS (Mean High Water Spring) and MLWS (Mean Low Water Spring) level is used.

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This analysis gives mean rates of erosion or accretion trends for each profile along with the degree of foreshore steepening or flattening. Changes in the gradient of the beach between MHWS and MLWS are expressed in the form of the ‘Foreshore Change Classification system’ (Halcrow, 1988), shown on page 16. Positive Foreshore Change Parameter (FCP) values indicate a beach system advancing seaward and negative values show a system retreating landwards. The individual FCP numbers indicate flattening, steepening or no rotation. Figure 1 below demonstrates the principals of beach profile change – mean erosion/accretion and beach gradient – over time.

Figure 1 – Conceptual diagram of a beach profile showing shoreline advance/retreat and foreshore change parameter However, there is uncertainty in predicting coastal trends particularly where cyclical processes are involved and added to this are other uncertainties such as sea level rise. There are also areas where anthropogenic influences such as groynes and beach recharge will affect the overall trend of a profile.

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2.0 Study Area This report covers the Suffolk coastal frontage from Lowestoft south pier, to Felixstowe Landguard Point, on the northern bank of the Stour/Orwell estuary – a total length of 72km. The area is based upon the Shoreline Management Plan (SMP) boundary area for Suffolk (sub-cell 7). The remainder of the Suffolk coast, north of Lowestoft harbour lies within the North East Norfolk and North Suffolk SMP (sub-cell 6). This stretch of coast is characterised by soft eroding cliffs, shingle beaches and coastal lagoons (broads) and includes the estuaries of the Blyth, Alde and Ore, and Deben. The soft materials of the coastline make it easily eroded and increasingly vulnerable to the long term impacts of climate change. The majority of the coast is natural and as a result beaches have been able to behave naturally and roll back in response to natural processes. Longshore drift of beach material dominates much of this coastline resulting in unique shingle features such as Orfordness, at 16km long, one of the largest shingle spits in Europe; and Benacre Ness, a large mobile shingle beach which is steadily migrating northwards against the predominant net southerly drift at a rate of around 30m/yr (May, 2003). Lowestoft and Felixstowe are the two major urban centres in Suffolk and have been defended against coastal erosion with extents of sea wall and groynes for many years. Work on the South Felixstowe scheme was completed in October 2008 and consisted of T-shaped rock groynes and beach recharge. The Central Felixstowe scheme with additional rock groynes and beach recharge between Jacob’s Ladder and the War Memorial is due to be started in 2011. In addition to this some of the smaller isolated towns and villages have a long standing tradition of coastal defence such as Southwold and Aldeburgh. Southwold’s sea defences were updated in 2006 to include new rock groynes and beach recharge. Suffolk has a long history of coastal change with many storm and flooding events recorded over the centuries. The most notable being the great storm of January 1953 where flooding occurred on a large scale around the entire east coast of England with records showing that 40 people lost their lives in Suffolk mostly in the town of Felixstowe. There is also a long history of gradual coastal erosion of the cliffs with a number of villages documented as being lost to the sea over the centuries. The most famous of these is the village of Dunwich, once one of the most important East Anglian ports during the early Middle Ages. Beach management practices with soft engineering options have also been utilised along this stretch of coast. Reprofiling (by bulldozer) of the Dunwich to Walberswick shingle ridge following storm events used to be employed to protect the area of grazing marsh behind it. Similarly at Easton Broad reprofiling of beach sediments was undertaken to protect the lagoon and freshwater habitat. Such practices have recently ceased due their relative unsustainability and the lack of available sediment in the ridges. These frontages are now being left to roll back naturally in response to coastal processes and predicted sea level rise. However, shingle recycling works to recharge the neck at Slaughden are continuing. This scheme has used sediment from the neighbouring Sudbourne beach on Orfordness since 2002 to add sediment to beaches further north around the Martello Tower and at the neck where beach levels are receding. This study has looked at the coastline only and has not analysed data collected further inland beyond the mouths of the estuaries. A total of 74 strategic beach profiles along the Suffolk coast at roughly 1km intervals collected since 1991 have been included. Further site specific studies have been undertaken including more intensive scheme monitoring and which are available from the Shoreline Management Group.

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Map 2 – Suffolk frontage profile locations (north)


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Map 3 – Suffolk frontage profile locations (south)


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3.0 Analysis

3.1 Outline tidal observations Table 1 below and Figure 2 on page 7 show the general trend of results of the 74 strategic profiles from Lowestoft south pier to Felixstowe Landguard Point used in the tide level analysis. Two profiles were shown as ‘no trend’ – S2A1 at the Knolls, Felixstowe Ferry where mobile sandbars at low water do not give a meaningful result and at S2B4 East Lane, Bawdsey where erosion at the profile location has outstripped the ability to survey in that location. Appendix 1 lists the full results in more detail.

No. of profiles Percentage Accretion 24 32

No Change (+/- 0.2 m/yr) 14 19 Mean Trend Erosion

No trend 34 2

46 3

Flattening 25 34 Steepening 13 17 Foreshore

Gradient No rotation No trend

34 2

46 3

Hard defences1 21 28 Defences at profile location Natural defences# 53 72

Table 1 – general results of analysis showing mean trends, foreshore gradients and alongshore defences by number of profiles and percentage The majority of the Suffolk coast (72 per cent of profiles) is natural and not artificially held by defences of any kind. As a result beaches have been able to behave naturally and roll back in response to natural processes. Along the developed sections of coast at Lowestoft, Southwold and Felixstowe beaches are backed by concrete sea walls with groynes and are more constrained in their response. Of the 74 profiles, nearly half (46 per cent) show a general erosion trend over the last 19 years. The most significant trend of erosion was observed along the cliffs from Kessingland (south of Benacre Ness) to Covehithe and Easton Bavents, just to the north of Southwold. The highest erosion rate along this stretch was at Covehithe cliffs (SWD2) at -5.7m/yr. Other significant erosion trends were apparent at the southern end of shingle spit at Orfordness and the low cliffs at Bawdsey. A similar percentage of profiles (46 per cent) have shown no significant rotational change and most of these are attributed to the profiles with natural defences. A third of profiles showed a flattening trend, although a flattened profile does not necessarily equate to an accretional trend. Nearly a third of profiles (32 per cent) did show an accretion trend. There were four main areas of accretion; at Lowestoft; North Kessingland where accretion is attributed to Benacre Ness’s northerly migration; north Orfordness/Slaughden and at Shingle Street. The most significant accretion rate at North Kessingland (SWE8) was 16.9 m/yr. The following section offers a description of the results of the analysis as well as graphically showing the trends overlaid onto a suite of aerial photographs that were taken during summer 2010. All trends and rates expressed relate to changes of the foreshore between MHWS and MLWS. # includes cliffs, dunes, shingle beaches and areas of ‘beach management’ where beaches, generally fronting low-lying land, have undergone some intervention in the form of mechanical sediment redistribution occurring at some stage during the monitoring period

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S2B1 – Shingle Street accretion rate of 4.6 m/yr

Orfordness Lowestoft

SWE8 – Benacre Ness accretion rate of 16.9 m/yr

Covehithe Felixstowe Walberswick Thorpeness Bawdsey

Accretion/erosion trend (m

/yr)

Figure 2 – graph of erosion/accretion trends for Suffolk 1km profiles from Lowestoft to Felixstowe showing MHWS, MSL and MLWS

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3.2 Detailed observations 3.2.1 Lowestoft to Kessingland SWF8 – Lowestoft South Pier. There is a significant variability between winter and summer profiles prior to 1997, therefore 1992 – 1997 data has been discounted. The profile is located a few metres south of the pier and is complicated by the presence of a rock beach retention groyne which crosses the profile near the base of the foreshore. The profile shows a steepening trend from 1997 to 2010 with MHWSs moving onshore by an average of 15m. Mean erosion rate of -1.8 m/yr. SWE1 – Lowestoft Claremont Pier. Significant accretion trends at all levels with no beach rotation. Water levels have moved offshore by around 40m. The mean rate is 2.6 m/yr. SWE2 – Lowestoft Rectory Road. Significant accretion trends at all levels particularly at MHWS, which has moved offshore by around 65m to produce a steepened profile. Mean rate of 3.5 m/yr. SWE3 – Lowestoft Pakefield Road. A significant accretion trend up to summer 2002 followed by a period of erosion to winter 2008. Levels are now showing accretion again from 2008 with a noticeable flattened profile due to greater increase at MLWS. Profile shows an overall mean accretion trend of 3.6 m/yr. SWE4 – Pakefield All Saints Road. Cyclical trend at all levels with accretion to 2003 followed by another period of erosion to give a mean accretion trend of 0.5 m/yr. SWE5 – Pakefield Arbor Lane. Moderate erosion trends at all levels with mean rate of -1.3 m/yr. SWE6 – Pakefield, Pontin’s Holiday Camp. Variable trend pattern resulting in a mean erosion trend of -0.3 m/yr. SWE7 – Kessingland Heathland Caravan Park. Strong erosion trend from 1991 to summer 2002 followed by a period of sharp accretion of around 45 – 50m at all levels to 2010. Aerials show that this is due to the northerly migration of Benacre Ness building the beach outwards. The mean erosion value of -0.8 m/yr is therefore misleading. SWE8 – A massive accretion trend is evident from 1992 to 2005 with water levels moving around 250m offshore, an average rate of around 20m/yr. The trend then levels off and becomes slightly erosional from 2005 to 2010. This is due to the widest point of the ness, the apex, having passed north of this profile in the past few years. The mean trend is 16.9 m/yr with a steepened profile. This is by far the most significant accretion on the Suffolk coast, the full extent of this accretion goes off the chart in figure 2. May (2003) quoted a ness migration rate of around 30m/yr. However, our aerial analysis between 1992 and 2010 suggests that the rate might be at least twice this figure with the apex of the ness moving northwards by around 1.5 km in 19 years. SWE9 – Kessingland beach. This profile shows steep accretion rates up to 1999 followed by an erosional trend of -5 m/yr to 2010, a landward movement of around 60m and which clearly shows the effect of the passing ness system. SWE10 – Kessingland Beach Holiday Village. Significant steady erosional trend of -3.4 m/yr as the lower part of the ness migrates northwards with no rotation in beach levels. Water levels have retreated landwards by around 50m.

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Figure 3 - Benacre Ness at Kessingland migrating northwards against a net southerly drift. Significant changes in position and morphology are shown between 1992 and 2010 aerials 3.2.2 Kessingland to Southwold SWD1 – Benacre Denes. Strong erosional trend of -2.7 m/yr with landward movement of water levels by around 35m since 1996. There is no rotation in beach levels. SWD2 – Boathouse Covert. A huge erosional trend of -5.7 m/yr with water levels moving onshore by around 100m since 1992. This is by far the most significant erosional trend along the Suffolk coastal frontage.

1992 2010


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SWD3 – Covehithe cliffs. Significant erosional trends of -3.1 m/yr. Erosion seems to have slowed down since 1998 with evidence of beach flattening. SWD4 – Covehithe cliffs. Significant erosion at -3.8 m/yr with no beach rotation. These cliffs have retreated by around 68m in the period 1992 to 2010. SWD5 – Easton Wood. Significant erosion at all levels to give a mean erosional trend of -3.4 m/yr with slight profile flattening. SWD6 – Easton Marshes cliffs. Steep erosion to 1997 followed by moderate and cyclical patterns of erosion and accretion giving a total mean erosional trend of -1.8 m/yr. SWD7 – Easton Bavents cliffs. Moderate erosion rates to 2004 followed by a slight period of accretion giving a mean trend of -2.1 m/yr. SWD8 – Southend Warren. This profile is located just to the north of the limit of the Southwold sea wall where private works have been carried out to combat the outflanking of the sea wall by the eroding cliffs. Concrete tripods are also located on the beach in front of the cliff face. There are fluctuations in the movement of water levels probably due to these works. However, there is a mean moderate erosional trend of -2.2 m/yr.

Figure 4 – Historic changes to Easton Bavents cliffline, north of Southwold, from 1884 to 2009

© Environment Agency copyright and/or database rights 2011. All rights reserved.

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SWD9 – North Parade, Southwold. Highly variable beach levels with no overall significant trend thus showing a mean trend of no movement. SWD10 – Gun Hill, Southwold. Cyclical patterns of erosion and accretion within an overall moderate accretion trend of 1.9 m/yr. There is definite beach flattening with MHWSs moving 50m offshore since 1997. SWD11 – North Pier Southwold. Highly variable beach levels with no overall significant trend giving a mean trend rate of 0.4 m/yr with beach flattening. [A detailed study of the area between Benacre Denes (SWD1) to Walberswick (S1C2) is available as a Coastal Trends and Beach Morphology Report, (March 2010)]. 3.2.3 Walberswick to Dunwich S1C1 – South Pier, Walberswick. Cyclical periods of erosion and accretion within an overall low erosional trend of -1.4 m/yr with water levels moving by around 50m on and offshore. 2010 levels are 50m further onshore than 1998 levels. S1C2 – Corporation Marshes, Walberswick. Small and steady accretional trend of 0.5 m/yr with no beach rotation. S1C3 – Walberswick. Significant erosion trend of -2.2 m/yr with slight beach flattening. S1C4 – Dunwich. Stable frontage, no movement. S1C5 – Dunwich. Mean trend of 0.4 m/yr due to steady accretion since 2005. No beach rotation. S1C6 – Dunwich, East Friars House. Slight erosional trend of -0.3 m/yr although since 2003 levels have shown a slight accretion trend. S1C7 – Dunwich, Cliff House Caravan Park. No movement, stable frontage. 3.2.4 Dunwich Heath to Thorpeness S1B1 – Dunwich Heath. Moderate erosion at all levels. Mean trend is -1.3 m/yr with slight beach steepening. S1B2 – Dunwich Heath. Slight accretion trend to 2000 followed by a significant erosion trend of -3 m/yr to 2010. However, there is no rotation in beach levels. S1B3 – Minsmere. Highly variable beach levels at all levels within a slowly accreting trend of 0.5 m/yr with no beach rotation. S1B4 – Minsmere Haven. Moderate erosion trends at all levels. A more accelerated rate of erosion is evident from 2001, giving a mean trend of -1.3 m/yr. S1B5 and S1B6 – Sizewell. Data from both profiles shows erosion to 1999/2000 followed by a period of accretion to 2010, resulting in no overall movement in trends. S1B7 – Sizewell Hall. Slight accretion at all levels. Mean trend of 0.3 m/yr. S1B8 – Thorpeness. Fairly stable beach with no overall movement. 3.2.5 Thorpeness to Orfordness Lighthouse S1A1 – Thorpeness. Very dynamic beach showing overall accretion to 2001 followed by a period of relative erosion to 2010 with beach levels returning to landwards of their 1991 position. This has resulted in a mean trend of no movement.

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Just to the north of this profile an area of emergency beach protection works has just taken place. Storms in June 2010 swept sediment out to sea revealing gabion baskets (put in place in the 1970s to protect the coast) and erosion of an unprotected cliff face further north. Works consisted of the placement of sand/shingle filled geotextile bags to form a new toe at the foot of the existing defences along with new rock-filled wire baskets laid above the extended toe to the top of the crest.

Figure 5 – Changes in beach morphology at Thorpeness – 1992 to 2010 S1A2 – Thorpeness. Moderate rates of erosion at all levels with no beach rotation. Mean trend of -0.8 m/yr. S1A3 – Aldeburgh. Moderate erosional trend of -1 m/yr with no foreshore steepening. S1A4 – Aldeburgh. Slight accretion at all levels, greater at MHWS to give a slightly steepened profile. Overall trend is 0.2 m/yr. S1A5 – Aldeburgh. High accretion trend to 1997 at all levels. The beach is very dynamic with subsequent years showing periods of erosion and accretion. The overall trend is slightly accretional at 0.4 m/yr. S1A6 – Martello Tower, Slaughden. No movement. No significant trend apparent. [N.B. Slaughden scheme profiles (not analysed in this report) immediately to the north and south of S1A6 all show moderate erosional trends].

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S1A7 – Slaughden. Stable beach showing moderate accretion at all levels with some beach flattening. Mean trend is 1 m/yr. S1A8 – Orfordness. Beach levels were very stable to 2000. Following this a period of steep accretion occurred at 2 m/yr to 2010. S1A9 – Orfordness. Significant accretion of 2.9 m/yr with no foreshore steepening. Water levels have accreted 60m further offshore in the 1991 to 2010 period. S1A10 – Orfordness. Moderate accretion of 1.3 m/yr with no foreshore steepening.

Figure 6 – Historic changes in beach morphology at Orfordness between 1884 to 2010

S1A11 and S1A11A – Orfordness. Both profiles originate at the same point on Orfordness adjacent to the apex of the ness where the orientation of the coast changes to SSE. Both profiles show significant erosional trends of -1.6 and -3.3 m/yr respectively although no foreshore steepening is apparent. S1A11 has retreated by 35m at MHWS and S1A11A by 72m since 1991. S2C6 – Orfordness lighthouse. Significant erosion of -3.6 m/yr but no foreshore steepening is apparent. MHWSs have retreated by 62m since 1991.


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3.2.6 Southern Orfordness S2C7 – Orfordness. Moderate erosion of -1.2 m/yr with signs of slight foreshore steepening. S2C8 – Orfordness. Slight erosional trend of -0.3 m/yr but no foreshore steepening. S2C9, S2C10, S2C11 and S2C12 – Orfordness. All profiles show small accretional trends, between 0.1 and 0.6 m/yr, with no beach rotation. S2C13 and S2C14 – Orfordness. Slight to moderate accretion (0.3 to 0.8 m/yr) with no foreshore steepening representing a very stable beach. 3.2.7 Shingle Street to Bawdsey Manor S2B1S – Shingle Street North. No overall movement. Sediment moving south from the tip of Orfordness bypasses the mouth of the Ore and either merges with the ness at Shingle Street or joins the mobile sand bar features visible at low water. Although there was an accretional spike around 2003 water levels have returned to their previous constant levels giving no apparent trend of accretion or erosion. S2B1 – Shingle Street. Significant accretion trend of 4.6 m/yr with no foreshore steepening. MHWSs have moved 80m further offshore since 1991 giving the second highest accretion trend along the Suffolk frontage.

Figure 7 – Changes in beach morphology at Shingle Street and the southern tip of Orfordness 1992 to 2010

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S2B2A – Shingle Street beach. Cyclical pattern of trends with a period of erosion to 1998 followed by a period of accretion to 2006. There then appears to be another period of erosion to 2010 giving an overall trend of no movement. S2B3A – Bawdsey Beach. Strong erosional trend of -2.2 m/yr with some foreshore steepening. MHWSs have receded by 36m since 1991. S2B4 – East Lane Bawdsey. There are few data points recorded at this location due to the beach at this transect having now mostly disappeared and there is therefore no trend. S2B5 – Bawdsey Beach. Strong erosion at all levels since 1997 with slight beach flattening to give a mean erosional trend of -1.8 m/yr. S2B6 and S2B7 – Bawdsey Beach and Bawdsey Manor. Slight erosional trends of less than -0.2 m/yr. [More information on the detailed trends at Bawdsey from S2B1S to S2B7 can be found in the Bawdsey Beach Morphology Report (2010)]. 3.2.8 Felixstowe Ferry to Landguard Point S2A1 – Felixstowe Ferry, The Knolls. As with S2B1S sediment bypassing the mouth of the Deben forms the Knolls, a series of mobile, transient sand/shingle bars. This results in high profile variability due to their rapid redistribution following storm events (English Nature, 2002). There is therefore no meaningful trend at this location. S2A2 – Felixstowe, The Dip. Very small erosional trend of -0.2 m/yr. S2A3, S2A4, S2A5 and S2A6 – Felixstowe, Jacobs Ladder to south of the pier. This section of coast is protected by hard defences of rock groynes and concrete sea wall. Moderate erosion trends for all profiles of between -0.4 to -0.8 m/yr. S2A3 shows no movement at MHWS. S2A7 – Felixstowe, Manor End. Slight to moderate accretion trend (0.6 m/yr) mainly due to a sharp accretion spike in winter 2009 as a result of beach recharge works between the groynes, as part of the South Felixstowe scheme completed in 2008. S2A8 – Felixstowe, Landguard Point. Moderate accretion trends at all levels giving a mean trend of 1.3 m/yr and slight beach flattening.

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3.3 Trends analysis maps The following section displays the mean trends of all profiles together with the Foreshore Change Parameter – a score of foreshore steepening or flattening – overlaid onto 2010 aerial photographs. Figures 8 and 9 below give a key to interpreting the trends analysis maps.

Figure 8 – Foreshore change classification system (adapted from Halcrow, 1988). The change is indicated in red

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Figure 9 – Key to trends analysis maps

(FCP)

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All rights reserved.© Crown copyright and database rights 2011 Ordnance Survey 100024198. © Environment Agency copyright and/or database rights 2011.

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Appendices Appendix 1 – Detailed results

Profile Metres per year Mean FCP Name Location Defence MHWS MSL MLWS Rate Score Notes SWF8 Lowestoft South Pier seawall and groyne -0.80 -1.79 -2.74 -1.8 -6 data from summer 1997 onwards SWE1 Lowestoft Claremont Pier seawall and groyne 2.56 2.74 2.41 2.6 5 no rotation SWE2 Lowestoft Rectory Road seawall and groyne 4.16 3.43 2.88 3.5 4 SWE3 Lowestoft Pakefield Road seawall and groyne 3.29 3.50 3.98 3.6 6 SWE4 Pakefield All Saint's Road seawall and groyne 0.37 0.51 0.51 0.5 6 SWE5 Pakefield Arbor Lane cliffs -1.46 -1.35 -1.13 -1.3 -4 SWE6 Pakefield Pontin's Holiday Camp cliffs -0.37 -0.18 -0.29 -0.3 -5 no rotation SWE7 Kessingland Heathland Caravan Park cliffs -1.28 -0.91 -0.18 -0.8 -4 SWE8 North Kessingland sea wall 17.74 17.41 15.55 16.9 4 ness migrating northwards SWE9 Kessingland beach sea wall -5.07 -5.00 -5.00 -5.0 -5 data from summer 1998 onwards SWE10 Kessingland beach holiday village dunes -3.43 -3.36 -3.43 -3.4 -5 no rotation SWD1 Benacre Denes dunes/shingle barrier -2.66 -2.66 -2.70 -2.7 -5 data from summer 1996 onwards SWD2 Boathouse Covert cliffs -5.73 -5.73 -5.51 -5.7 -5 SWD3 Covehithe cliffs cliffs -3.36 -3.39 -2.66 -3.1 -4 SWD4 Covehithe cliffs cliffs -3.83 -3.83 -3.72 -3.8 -5 no rotation SWD5 Easton Wood cliffs -3.65 -3.58 -2.96 -3.4 -4 SWD6 Easton Marshes cliffs cliffs -2.04 -1.83 -1.46 -1.8 -4 SWD7 Easton Bavents cliffs cliffs -2.34 -2.12 -1.93 -2.1 -4 SWD8 Southend Warren cliffs -2.34 -2.26 -2.04 -2.2 -4 SWD9 North Parade, Southwold seawall and groyne -0.29 -0.22 0.07 -0.1 -2 SWD10 Gun Hill, Southwold seawall and groyne 1.53 1.79 2.34 1.9 6 SWD11 North Pier Southwold dunes -0.29 0.15 1.46 0.4 -2 S1C1 South Pier Walberswick dunes -1.53 -1.46 -1.17 -1.4 -4 S1C2 Corporation Marshes Walberswick shingle bank managed 0.47 0.55 0.55 0.5 5 no rotation S1C3 Walberswick shingle bank managed -2.37 -2.30 -1.93 -2.2 -4 S1C4 Dunwich shingle bank no longer managed 0.01 -0.02 0.04 0.0 0 no movement S1C5 Dunwich shingle bank no longer managed 0.40 0.40 0.44 0.4 5 no rotation S1C6 Dunwich, East Friars House cliffs -0.37 -0.33 -0.22 -0.3 -4 S1C7 Dunwich, Cliff House Caravan Park cliffs 0.04 0.07 -0.07 0.0 0 no movement S1B1 Dunwich Heath cliffs -1.20 -1.28 -1.42 -1.3 -6 S1B2 Dunwich Heath sand/shingle bank -1.17 -1.20 -1.20 -1.2 -5 no rotation

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S1B3 Minsmere dunes 0.58 0.51 0.51 0.5 5 no rotation S1B4 Minsmere Haven dunes -1.31 -1.31 -1.31 -1.3 -5 no rotation S1B5 Sizewell dunes backed by Sizewell bank 0.04 0.07 0.29 0.1 1 no movement S1B6 Sizewell dunes backed by Sizewell bank -0.22 -0.15 -0.04 -0.1 0 no movement S1B7 Sizewell Hall cliffs 0.18 0.29 0.33 0.3 6 S1B8 Thorpeness cliffs -0.07 -0.07 -0.04 -0.1 0 no movement S1A1 Thorpeness shingle beach 0.15 0.07 0.07 0.1 0 no movement S1A2 Thorpeness shingle beach -0.80 -0.88 -0.73 -0.8 -5 no rotation S1A3 Aldeburgh shingle ridge -0.95 -1.02 -1.06 -1.0 -6 S1A4 Aldeburgh sea wall and groynes 0.26 0.15 0.15 0.2 4 S1A5 Aldeburgh sea wall 0.58 0.47 0.26 0.4 4 S1A6 Slaughden, Martello Tower sea wall and groynes -0.02 -0.07 -0.15 -0.1 0 no movement S1A7 Slaughden shingle bank 0.88 0.91 1.13 1.0 6 S1A8 Orfordness shingle bank 1.02 1.10 1.20 1.1 6 S1A9 Orfordness shingle 2.81 2.85 2.96 2.9 6 S1A10 Orfordness shingle 1.28 1.20 1.39 1.3 6 S1A11 Orfordness shingle -1.61 -1.61 -1.53 -1.6 -5 no rotation S1A11A Orfordness shingle -3.21 -3.29 -3.36 -3.3 -6 S2C6 Orfordness lighthouse shingle -3.58 -3.58 -3.54 -3.6 -5 no rotation S2C7 Orfordness shingle -1.06 -1.06 -1.35 -1.2 -6 S2C8 Orfordness shingle -0.33 -0.29 -0.29 -0.3 -5 no rotation S2C9 Orfordness shingle 0.55 0.58 0.62 0.6 5 no rotation S2C10 Orfordness shingle 0.29 0.33 0.37 0.3 5 S2C11 Orfordness shingle 0.18 0.22 0.29 0.2 6 S2C12 Orfordness shingle 0.11 0.15 0.18 0.1 0 no movement S2C13 Orfordness shingle 0.29 0.33 0.26 0.3 5 no rotation S2C14 Orfordness shingle 0.77 0.80 0.80 0.8 5 no rotation S2B1S Shingle Street north shingle bank 0.11 0.18 -0.01 0.1 0 no movement S2B1 Shingle Street shingle bank 4.67 4.64 4.60 4.6 5 no rotation S2B2A Shingle Street Beach shingle backed by embankment 0.22 0.07 0.11 0.1 0 no movement S2B3A Bawdsey Beach shingle backed by embankment -2.01 -2.19 -2.37 -2.2 -6 S2B4 Bawdsey Beach rock hard point 0.0 no data S2B5 Bawdsey Beach cliffs -2.01 -1.86 -1.64 -1.8 -4 S2B6 Bawdsey Beach cliffs -0.18 -0.18 -0.11 -0.2 0 no movement S2B7 Bawdsey Manor revetments and old timber groynes -0.18 -0.22 -0.18 -0.2 0 no movement S2A1 Felixstowe Ferry, the Knolls shingle backed by sea wall 0.0 no trend S2A2 Felixstowe, The Dip sea wall and groynes -0.15 -0.18 -0.22 -0.2 0 no movement

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S2A3 Felixstowe Jacobs Ladder sea wall and groynes -0.07 -0.80 -0.77 -0.5 -1 S2A4 Felixstowe Undercliffe Rd East sea wall and groynes -0.33 -0.33 -0.47 -0.4 -6 S2A5 Felixstowe Town Hall sea wall and groynes -0.29 -0.58 -0.26 -0.4 -5 no rotation S2A6 Felixstowe South of Pier sea wall & T-shaped rock groyne -0.84 -0.80 -0.66 -0.8 -4 S2A7 Felixstowe Manor End sea wall & T-shaped rock groyne 0.66 0.66 0.44 0.6 4 S2A8 Felixstowe Landguard Point dunes and shingle 1.24 1.35 1.42 1.3 6

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Appendix 2 – References Birkbeck College/University College London Joint Research School of Geological and Geophysical Sciences, 1999. Analysis of Coastal Change: Monitoring and Modelling of Erosion and Sedimentation along the Suffolk Coast. Shoreline Monitoring Preliminary Report. Environment Agency English Nature, Environment Agency, Defra, Natural Environment Research Council, 2002 Suffolk Coastal and Estuaries Coastal Habitat Management Plan. Royal Haskoning Environment Agency, 2007. Suffolk Coastal Trends Analysis, Shoreline Management Group, EA Halcrow, 2001. Lowestoft to Thorpeness Coastal Process and Strategy Study, Environment Agency May, V J, 2003, Benacre Ness. Coastal Geomorphology of Great Britain, Geological Conservation Review Series No 28 (V J May and J D Hansom) Joint Nature Conservation Committee, Peterborough, pp 301 – 304 Pontee, N I, 2005, Management Implications of Coastal Change in Suffolk, UK. Maritime Engineering 158, Issue MA2, pp 69 - 83 Royal Haskoning, 2010. Shoreline Management Plan 7, Lowestoft Ness to Felixstowe Landguard Point, Appendix C, Review of Coastal Processes and Geomorphology. Suffolk Coastal District Council SANDs software by Halcrow Group Plc http://www.halcrow.com/sands Taylor, J A, Murdoch, A P & Pontee, N I 2004, A Macroscale Analysis of Coastal Steepening Around the Coast of England and Wales, The Geog. Journal, Vol 170, No 3, pp 179 – 188 Townend I and McLaren P 1988. Anglian Coastal Management Atlas, Sir William Halcrow & Partners Waveney District Council, 1998. Benacre Ness to Thorpeness Strategy/Process Study Project Appraisal Report. Community Services Department

coastal trends report - channel coast … · longshore drift of beach material dominates much of...

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