Old Hunstanton to Kelling 2012

Coastal Trends Report North Norfolk (Old Hunstanton to Kelling)

RP028/L/2011 October 2012

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Blakeney Spit from Morston Quay (Photo: Environment Agency)

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

Gabions Stone filled wire baskets which are used to raise beach levels.

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

North Norfolk 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 ...... 5

3.1 OUTLINE TIDAL OBSERVATIONS ...... 5

3.2 DETAILED OBSERVATIONS ...... 8

3.2.1 OLD HUNSTANTON TO GORE POINT ...... 8

3.2.2 BRANCASTER BAY...... 8

3.2.3 SCOLT HEAD ISLAND ...... 9

3.2.4 GUN HILL TO WELLS-NEXT-THE-SEA ...... 11

3.2.5 WELLS-NEXT-THE-SEA TO BLAKENEY ...... 11

3.2.6 BLAKENEY POINT TO WEYBOURNE ...... 13

3.3 TRENDS ANALYSIS MAPS ...... 15 - 23

Appendix 1 – DETAILED RESULTS ...... …...... 24

Appendix 2 – REFERENCES ...... 26

Map 1 – Shoreline Management Plan 2 boundaries (2011)

iii

1.0 Introduction

1.1 Coastal Monitoring

The Shoreline Monitoring 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 started a new five year phase of monitoring in 2011 (Phase VIII) which collects 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 (ie 250m)

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 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 North Norfolk Coastal Trends (2007) analysis, now incorporating data up to and including winter 2011 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 Holme dunes and Cley shingle ridge 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 which commenced in April 2011, 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 analysis for the years 1991 to 2011.

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 levels and in this report the area between the MHWS (Mean High Water Spring) and MLWS (Mean Low Water Spring) or MLWN (Mean Low Water Neap) is used. 1

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 15. 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.

2.0 Study Area

This report covers the North Norfolk coastal frontage from the cliffs at Old Hunstanton in the Wash to the cliffs at Weybourne, Kelling – a total length of 75km. The area is based upon the Shoreline Management Plan (SMP) boundary area for North Norfolk (sub-cell 5).

The North Norfolk frontage is comprised of a series of sand and gravel barrier systems that front and provide protection for extensive networks of saltmarsh, some of which have been reclaimed, along with extensive creek systems and lagoons typical of this type of environment. The most significant features are Scolt Head, a barrier island and Blakeney Ridge, a spit. Seawards of high water there are extensive sandflat foreshores that in places extend for kilometres down to low water.

The entire length of coast benefits from the following designations:

North Norfolk Coast SAC North Norfolk Coast Ramsar site The Wash and North Norfolk Coast SAC North Norfolk AONB North Norfolk Coast SPA North Norfolk Coast SSSI

This stretch of coast is characterised by wide sandy expanses, saltmarsh and shingle ridges. There are relatively few classic hard defences in this area such as sea walls, groynes or revetments compared with other frontages along the Anglian coastline. The majority of the North Norfolk coast is natural and as a result beaches have been able to behave naturally and roll back in response to natural processes.

In places, property, farmland and fresh marshes are offered some protection from exceptional tide levels by raised earth embankments that have in places been reinforced. However, these tend to be subtle and often form the track of the North Norfolk coastal path. An exception to this is the privately funded short length of steel sheet piling and rock armourstone adjacent to the Royal West Norfolk Golf Club near Brancaster. To the west of this site a 400m length of gabion revetment, in poor condition, was breached in 2002 to become Brancaster West Marsh Management Realignment site, one of the first managed realignment schemes to be implemented in the UK. Previously a freshwater grazing marsh it now provides enhanced flood defence at reduced cost and environmental benefits through the creation of 7.5ha of saltmarsh habitat.

The North Norfolk coastal is popular with walkers, naturalists, birdwatchers, horse riders and also sailors. There are a number of sailing clubs along the coast.

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 46 strategic beach profiles along the North Norfolk 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.

North Norfolk 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 over eighty people lost their lives in Norfolk.

Beach management practices with soft engineering options have also been utilised along this stretch of coast. Reprofiling (by bulldozer) of the Cley/Salthouse shingle ridge following storm events used to be employed to protect the area of grazing marsh behind it. 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. A number of defence practices have also previously been utilised at Holme dunes including a beach dewatering scheme and various methods of dune fencing.

In early 2012 the natural sand dune defences at Old Hunstanton were strengthened. Recycling of existing sand from the beach was placed on the top of six gabion groynes and planted with marram grass to encourage wind blow sand. This in time will form new sand dunes and form a more sustainable dune system.

Map 2 – North Norfolk frontage profile locations

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 46 strategic profiles from Old Hunstanton to Weybourne used in the tide level analysis. Appendix 1 lists the full results in more detail.

No. of profiles Percentage

Accretion 14 30.5 Mean No Change (+/- 0.2 m/yr) 7 15 Trend Erosion 25 54.5

Flattening 13 28 Foreshore Steepening 18 39 Gradient No rotation 15 33

Defences at Hard defences 1* 2 4 profile location Natural defences# 44 96

Table 1 – general results of analysis showing mean trends, foreshore gradients and alongshore defences by number of profiles and percentage

The majority of the North Norfolk coast (96 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.

Of the 46 profiles over half (54 per cent) have shown an erosional trend of the foreshore over the last 20 years with nearly 40 per cent of profiles showing a steepening trend. However, as a significant feature of this frontage is the broad expanses of sandflats where in some places the foreshore can extend several kilometres seawards of high water springs, rotational changes can sometimes be insignificant, but are still included in this report.

The most significant trend of erosion was observed at Blakeney Point dunes, -4.3 m/yr (N2C2) adjacent to the profile with the highest accretion trend (4.7 m/yr, N2C1). Other significant erosion trends were apparent at Holme dunes (N1C1), Scolt Head Island (N1B2), Holkham dunes (N1A5) and Burnham (N1A1).

A third of profiles have not shown any significant rotational change and most of these are attributed to the shingle ridge at Blakeney, Kelling which is maintaining profile. In addition, 39 per cent of profiles showed a steepening trend although a steepening profile does not necessarily equate to an erosional trend.

Thirty per cent of profiles showed an accretional trend. There were four main areas of accretion; at Stiffkey marshes, Blakeney Point, Old Hunstanton dunes and Titchwell. The most significant accretion trend was at Blakeney Point dunes, 4.7 m/yr at N2C1.

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 2011. All trends and rates expressed relate to changes of the foreshore between MHWS and MLWS (or MLWN where there is little MLWS data).

* N.B Thornham embankment does not affect the foreshore processes, although the rock revetment at the clubhouse is located around MHWS level and therefore does affect foreshore processes

# 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

MHWS MSL MLWS 10

Accretion/erosion trend(m/yr) 5

-5

Holme Titchwell Scolt Head Island Holkham Meals Wells Stiffkey Blakeney Salthouse

-10

N1D4 N1D5 N1D6 N1D7 N1C1 N1C2 N1C3 N1C4 N1C5 N1C6 N1C7 N1B1 N1B2 N1B3 N1B4 N1B5 N1B6A N1A1 N1A2 N1A3 N1A4 N1A5 N1A6 N1A7 N1A8 N2D1 N2D2 N2D3 N2D4 N2D5 N2D6 N2C1 N2C2 N2C3 N2C4 N2C5 N2C6 N2C7 N2C8 N2B1 N2B2 N2B3 N2B4 N2B5 N2B6 N2B7

Figure 2 – graph of erosion/accretion trends for North Norfolk 1km profiles from Old Hunstanton to Weybourne showing MHWS, MSL and MLWS / MLWN

3.2 Detailed observations

3.2.1 Old Hunstanton to Gore Point

N1D4 – Strong accretion trends particularly at HWN and MSL. At HWS this accretion trend is more moderate with little movement at LWS. There is a mean accretion trend of 1.8 m/yr. There is a wide foreshore of around 750m.

N1D5 – Massive accretion trend at HWS (9.2 m/yr) due to the onshore movement of sandbars increasing beach levels. HWSs have moved seawards by around 177m since 1992 as a result. The mean trend of accretion is much lower at 2.6 m/yr due to the influence of the erosional trend at MSL and little movement at LWN.

N1D6 – A mean trend of erosion of 0.3 m/yr despite a moderate accretion trend at HWS of 2.6 m/yr where dunes are accreting seawards through the onshore movement of sandbars. MHWS have accreted seawards by 25m since 1992. MSL shows a similar level of erosion. Cyclical patterns of erosion/accretion are due to the dynamic dune systems.

Summary

This area is dominated by chalk and carstone cliffs that are undergoing erosion, fronted by wide sand and a shingle beach. Annual longshore wave energy of 0 – 500 kNs-1 increases towards Gore Point to 1000 – 1500 kNs-1. There is upper beach southerly littoral transport with lower foreshore northerly tidal.

The dunes at Old Hunstanton show relatively strong accretional trends with the western profile at Home dunes, N1D6, showing a slight erosional trend despite the strong accretion at high water.

3.2.2 Brancaster Bay

N1D7 – Small erosion trends at HWS and LWS of around 0.5 m/yr with greater erosion at MSL to give a mean trend of -1.3 m/yr. This corresponds with erosion of the dune face at HWS/HAT levels by around 12m.

N1C1 – Moderate erosional rates at all water levels to give a mean trend of -1.8 m/yr. This section of dune is fronted by ‘dragon tooth’ fencing in an attempt to impede sediment removal at the dune face. Since 1991 dunes have receded by around 15m at HWS level and by a height of nearly 4mAOD.

[The Coastal Trends Analysis report for Holme-next-the-Sea 2009 details the morphology of this area and is available from the SMG].

N1C2 – Water levels appear very cyclical with recent accretion at HWS in the last few years. Moderate erosion trends exist at MSL and LWN. There is a mean erosion trend of -1.2 m/yr. The foreshore is wide at around 1 km with evidence of much dune loss and lowering at this profile.

N1C3 – Slight accretion trends at all levels with a mean rate of 0.5 m/yr. The dunes have accreted by around 6m since 1991 at the dune face.

N1C4 – There is erosion of the upper beach at 0.7 m/yr with a small amount of accretion at MSL and LWS. The dunes here have retreated by around 24m since 1991.

N1C5 – Overall there is no movement at HWS with moderate to significant accretion at MSL to LWS to produce a flattened profile. The foredunes have increased in height by 1.5m since 1991. The mean accretion rate is 1.8 m/yr.

N1C6 – There is a rock revetment defence protecting the clubhouse at this location so there is no movement at HWS. Moderate accretion at MSL. Brancaster harbour crosses this profile above LWS where water levels are highly variable but show overall significant accretion trend. This gives the profile a mean accretion trend of 2.6 m/yr with beach flattening.

N1C7 – This profile shows a relatively stable upper and lower beach with accretion of around 1 m/yr and HWS/LWS. However at MSL there is significant recession at -6.5 m/yr. There is accretion in dune height (14-15.5mAOD) and at the dune face by 20m since 1991.

Summary

An area of dunes and beach ridges in front of both claimed marshland and natural saltmarsh. Annual longshore wave energy is 1000 – 1500 kNs-1.

The profiles at Holme dunes west of Thornham Harbour channel all show a moderate erosional trend. East of the channel all profiles are showing an accretional trend up to the Royal West Norfolk clubhouse rock revetment. The last profile at Brancaster dunes is again eroding.

3.2.3 Scolt Head Island

N1B1 – This profile is located at the western edge of Scolt Head Island which has accreted significantly since 1991 both westwards and in a shore normal direction. HWS shows an accretion trend of 3.7m/yr which equates to 44m in the 20 year period . Dune heights have accreted from 5mAOD to 6.75mAOD. Although up until 1996 the location of the western spur was transient by around 100m further south.

N1B2 and N1B3 – Water levels show an erosional trend at all levels which are more significant at LWS to produce a mean steepening trend of -1.9 m/yr and -1.4m/yr respectively, indicating a significant narrowing and retreat of the barrier beach at this point.

N1B4 – A small amount of erosion at MHW and at MSL. No movement at LWN. There is a mean erosion trend of 0.7 m./yr resulting in retreat and lowering of the seaward dunes.

N1B5 – No movement at LWN. There is minimal erosion trend at MSL and HWS with a mean erosion trend of -0.3 m/yr. The seaward dune face shows retreat although increasing in crest height.

N1B6A – Small erosion trends at high and low water with moderate accretion at MSL to give a mean accretion trend of 0.3 m/yr. The foreshore dune field has moved landwards by around 7m but increased in crest height by nearly 3m AOD since 1991.

Summary

Scolt Head Island is deemed to be the best example of a barrier island on the British coast (Steers, 1981). Annual longshore wave energy is 500 – 1000 kNs-1.

The four central profiles at Scolt Head Island are all showing erosional trends with greater erosion at the western end. The outer most east and west profile at Scolt Head show accretion with the accretion at the western profile, N1B1, consistent with the western migration of the island.

Figure 3 – Aerial comparisons of the western end of Scolt Head Island showing westerly accretion and migration between the years 1992 to 2011.

3.2.4 Gun Hill to Wells-next-the-Sea

N1A1 – Very strong erosion trends at all levels to give a mean rate of -3.8 m/yr. This erosion has resulted in foredune recession above high water of 60m since 1991.

N1A2 – Moderate erosion at HWS and MSL with moderate accretion at LWN giving a mean rate of - 0.5 m/yr. Foredunes have retreated landwards whilst gaining in crest height since 1991. Accretion at LWN gives a flattening profile.

N1A3 – No movement at HWS. Moderate accretion at MSL with slight erosion at LWS to give a mean trend of accretion at 0.5 m/yr. Stable profile/foreshore with dunes accreting in height.

N1A4 – A trend of no movement at high water despite which there is substantial foredune accretion of 23m since 1991. Just above MSL there is slight erosion, with slight erosion at LWS.

N1A5 – Fairly strong erosion trends at all levels giving a mean rate of -2 m/yr with no beach rotation. Mobile dune field has successively eroded and rebuilt itself and is now 20m further landwards than in 1991.

N1A6 – Moderate erosion of -1.6 m/yr at HWS with a high amount of erosion at LWS of -4.6 m/yr. At MSL there is an accretion trend. This appears to be indicative of sandbars migrating onshore but which has resulted in dune recession with increasing crest height.

N1A7 – Very high erosion rate of -5.6 m/yr at HWS which has resulted in substantial dune loss above high water and retreat of high water by 100m. However low water shows a massive accretion trend of 11 m/yr. The mean trend of 1.1 m/yr is therefore fairly meaningless.

N1A8 – A 170m gabion revetment with timber piled apron protects the backshore dune ridge at this location. There is a small erosion trend in front of this defence at HWS, a retreat of 15m since 1991. There is a massive accretion trend at MSL of 11 m/yr due to the broad sand expanse in front of the main channel leading to Wells harbour. LWS are eroding with a trend of -5.6 m/yr. The mean trend of accretion at 1.5 m/yr is therefore unreliable.

Summary

This area is generally known as Holkham Bay with the backshore dominated by an extensive line of dunes known as Holkham Meals. Large sections of these dunes have been forested with pines over the last 150 years. Annual longshore wave energy is 500 – 1000 kNs-1.

Much of this section of coast shows an erosional trend with the strongest trend at Burnham. There are also some isolated sections showing low accretion trends. Much of Holkham beach shows erosion with some steepening trends. At Wells lifeboat, N1A8 an overall accretion trend is due to high accretion at MSL, the broad sand in front of the main Wells harbour channel.

3.2.5 Wells-next-the-Sea to Blakeney

N2D1 – Data up to winter 2001 has been disregarded due to irregularities. There is a strong erosion trend of -3 m/yr at high water, with little movement at MSL and accretion at low water.

N2D2 – Saltmarsh – strong accretion trend at HWS of 2.7 m/yr with strong erosion trends at MSL and LWS giving a mean erosion trend of -0.8 m/yr.

N2D3 – Strong erosion trend at HWS of -2.5 m/yr with accretion trend at MSL and little movement at LWN giving a mean trend of -0.7 m/yr.

N2D4 – A line of low dunes separates saltmarsh on the landwards and seawards side. There is an accretion trend of 0.7 m/yr at HWS in front of the dune line. An accretion trend at MSL of 1.7 m/yr is

indicative of the seawards accretion of mud and sand lower down the profile in front of the saltmarsh. There is an erosion trend of -1 m/yr at LWS. Mean trend is 0.5 m/yr.

N2D5 – Erosion trend at HWS of the saltmarsh just above at -1.46 m/yr with strong accretion trends at MSL and LWN of 4.9 and 3.4 m/yr respectively, showing accretion of sand levels in front of the saltmarsh.

N2D6 – A low line of dunes separates saltmarsh on the landwards and seawards side. Erosion of the saltmarsh just above HWS line indicated by an erosion trend of -1.13. There is a massive accretion trend at MSL of 10.6 m/yr where sand/mud is accreting in front of saltmarsh. There is a small accretion trend at LWN of 0.7 m/yr. Mean trend is 3.4 m/yr.

Summary

This area encompasses large sections of saltmarsh at the landward side of the beach known as Wells, Warham and Stiffkey saltmarshes (from west to east). Annual longshore wave energy is 500 – 1000 kNs-1.

Mean trends of change along this section of coast display a generally small erosional trend for the three westerly profiles and an increasingly accretional trend for the easterly three profiles. However the mean trends are often misleading and therefore the individual water level trends need to be looked at separately.

Analysis of the horizontal saltmarsh extent along this frontage between 1992 and 2011 showed little change at N2D1. Between profiles N2D2 and N2D4 there is a marked loss of saltmarsh in this period. However, between N2D4 and N2D5 the rate of saltmarsh erosion is of a lesser extent. Profile N2D6 shows saltmarsh erosion of around 30m in the 1992 to 2011 period.

Figure 4 – Saltmarsh loss at Warham marshes. The blue dashed line indicates the1992 horizontal saltmarsh extent. This is overlaid onto 2011 aerials.

3.2.6 Blakeney Point to Weybourne

N2C1 – Strong accretion trends at all levels with the highest of 6.46 m/yr at LWN. The trends appear cyclical with a mean trend of 4.7 m/yr. The dune line here reaches 7m AOD in 2011, a 2m increase since 1991.

N2C2 – Moderate to strong erosion trends at all levels with a trend of -9.42 m/yr at LWN to give a mean erosion trend of -4.3 m/yr and a steepening profile. The foredune has retreated by 20m in 20 years. Stable back dunes.

N2C3 – There is a small erosion trend at all levels of around -0.5 m/yr with no beach rotation.

N2C4 – Steady moderate erosion trends at all levels of around -1.5 m/yr with no change in beach rotation, indicating roll back and lowering of the shingle ridge.

N2C5 – Moderate erosion at all levels of 0.9 – 1.0 m/yr with no beach rotation, indicating roll back and lowering of the shingle ridge.

N2C6 – Small erosion trend at all levels of 0.55 m/yr with no beach rotation indicating roll back and lowering of the shingle ridge.

N2C7 – Erosion at all levels of -0.6/0.7 m/yr indicating roll back, erosion and flattening of the shingle ridge.

N2C8 – Narrowing and retreat of the shingle ridge. Cyclical pattern of erosion and accretion within an overall erosion trend of -0.3 m/yr with no beach rotation.

N2B1 – Narrowing and retreat of the shingle ridge, cyclical pattern with lowering and retreat of the ridge and rebuilding but overall trend is no movement. 1991 – 2011 overall result is retreat and lowering.

N2B2 – Cyclical patterns of erosion and accretion with an overall trend of no movement,. Above MHWS the shingle ridge has flattened by over 2m in height. The foreshore width in this location is narrow at 26m. This high variability of beach levels is likely to be attributed to shingle recycling activities undertaken along the ridge up to 2006.

N2B3 – Cyclical patterns of erosion and accretion of the ridge face due to recycling activities with overall slight steepening of the narrow foreshore zone.

N2B4 – Cyclical patterns of erosion and accretion with a moderate trend of erosion of -0.5 m/yr at all levels, 10m in 20 years. There is a foreign body above HWS level at the foot of the ridge face. Crest height lowering by over one metre.

N2B5 – Cyclical pattern of beach levels within an overall trend of slight erosion of 0.2 m/yr. No rotation on this narrow foreshore of 25m.

N2B6 – Cliffs here have retreated by a steady rate. However, water levels show a cycle of erosion to 1997 and then accretion giving a small trend of accretion of the foreshore. There is no beach rotation. The foreshore is narrow at 22m.

N2B7 – Water levels show erosion in line with the cliff retreat. There is little movement at high water with greater erosion at LWN to give a steepened foreshore profile.

Summary

This area includes the recurved shingle spit of Blakeney consisting mainly of a single ridge of over 9km in length. Generally, the inland boundary is marked by a low buff (an earlier now degraded cliffline) or land-claim embankments.

The westerly migration of the Blakeney Point system can be seen with the rapid accretion at its tip at N2C1 and the erosion of profiles immediately to the east and along the spit length to N2C8. This is also clearly displayed in aerial comparisons between 1992 and 2011 in the figure below. The profiles 13

further east of the spit from N2B1 show little overall movement or slight erosion with the exception of N2B6 at Weybourne which shows slight accretion. In addition to this there is no trend of steepening with profiles maintaining gradient. Although much of this section of coast has been the subject of mechanical beach recycling and reprofiling over the length of the monitoring period this practice ceased in 2006.

Figure 5 – Aerial comparisons for Blakeney Point between 1992 and 2011 showing westerly migration and accretion

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

(FCP)

Figure 7 – Key to trends analysis maps

Appendix 1 - Detailed results

Metres per year Mean FCP Profile Location Defence MHWS MSL MLWS/N Rate Score Notes N1D4 Old Hunstanton dunes 0.91 4.42 0.07 1.8 3 N1D5 Old Hunstanton dunes 9.20 -1.68 0.22 2.6 3 MLWN N1D6 Holme dunes 2.63 -2.59 -0.91 -0.3 2 MLWN N1D7 Holme dunes -0.47 -2.74 -0.58 -1.3 -5 N1C1 Holme dunes/fencing -1.10 -2.52 -1.64 -1.8 -6 MLWN N1C2 Thornham Thornham embankment* 0.29 -1.06 -2.85 -1.2 2 MLWN N1C3 Thornham dunes 0.44 0.66 0.37 0.5 5 MLWN N1C4 Titchwell dunes -0.69 0.44 0.62 0.1 -2 N1C5 Titchwell dunes -0.03 2.15 3.25 1.8 1 N1C6 Royal West Norfolk clubhouse rock revetment 0.01 2.19 5.58 2.6 1 N1C7 Brancaster dunes 0.99 -6.57 0.84 -1.6 5 N1B1 Scolt Head Island dunes 3.76 -0.80 0.66 1.2 4 N1B2 Scolt Head Island dunes/saltmarsh -1.06 -1.35 -3.39 -1.9 -6 N1B3 Scolt Head Island dunes/saltmarsh -0.62 -0.99 -2.74 -1.4 -6 N1B4 Scolt Head Island dunes/saltmarsh -0.66 -1.28 -0.07 -0.7 -3 MLWN N1B5 Scolt Head Island dunes/saltmarsh -0.40 -0.51 0.04 -0.3 -3 MLWN N1B6A Scolt Head Island dunes/saltmarsh -0.51 2.34 -0.91 0.3 -6 MLWN N1A1 Burnham dunes -3.54 -5.07 -2.85 -3.8 -4 MLWN N1A2 Overy Marshes dunes -1.20 -2.08 1.86 -0.5 -2 MLWN N1A3 Overy Marshes dunes 0.11 2.37 -1.06 0.5 -1 N1A4 Holkham Meals dunes -0.07 -0.95 -0.22 -0.4 0 N1A5 Holkham Meals dunes -1.90 -2.41 -1.79 -2.0 -5 N1A6 Holkham Meals dunes -1.68 2.01 -4.64 -1.4 -6 N1A7 Holkham Meals dunes -5.58 -2.19 10.99 1.1 -2 N1A8 Wells Lifeboat stone gabions -0.88 10.91 -5.66 1.5 -6 N2D1 Wells salt marshes saltmarsh/dunes -2.96 0.18 1.39 -0.5 -4 trend from 2001S only N2D2 Warham salt marshes saltmarsh 2.70 -2.74 -2.23 -0.8 2 MLWN. Saltmarsh analysis N2D3 Warham salt marshes saltmarsh -2.56 0.84 -0.26 -0.7 -4 MLWN. Saltmarsh analysis N2D4 Stiffkey saltmarsh 0.69 1.75 -1.02 0.5 2 saltmarsh analysis N2D5 Stiffkey saltmarsh -1.46 4.93 3.43 2.3 -2 MLWN. Saltmarsh analysis N2D6 Stiffkey salt marshes saltmarsh -1.13 10.62 0.73 3.4 -2 MLWN. Saltmarsh analysis N2C1 Blakeney Point dunes 3.25 4.42 6.46 4.7 6 MLWN N2C2 Blakeney Point dunes -1.31 -2.19 -9.42 -4.3 -6 MLWN N2C3 Blakeney Point shingle ridge/dunes -0.51 -0.58 -0.47 -0.5 -5 N2C4 Blakeney shingle ridge -1.53 -1.46 -1.42 -1.5 -5 MLWN N2C5 Blakeney shingle ridge -0.91 -0.91 -0.99 -0.9 -5 MLWN 24

N2C6 Blakeney shingle ridge -0.55 -0.51 -0.55 -0.5 -5 MLWN N2C7 Cley Marshes shingle ridge -0.69 -0.58 -0.66 -0.6 -5 MLWN N2C8 Cley Marshes shingle ridge -0.33 -0.22 -0.29 -0.3 -5 MLWN N2B1 Cley Marshes shingle ridge 0.04 0.01 -0.15 0.0 -1 MLWN N2B2 Salthouse shingle ridge -0.04 0.04 -0.04 0.0 0 MLWN N2B3 Salthouse shingle ridge -0.04 -0.07 -0.18 -0.1 -1 MLWN N2B4 Kelling shingle ridge -0.51 -0.55 -0.58 -0.5 -5 MLWN N2B5 Kelling shingle ridge -0.22 -0.22 -0.26 -0.2 -5 MLWN N2B6 Weybourne cliff 0.22 0.18 0.11 0.2 5 MLWN N2B7 Weybourne cliff -0.07 -0.26 -0.37 -0.2 -1 MLWN

Appendix 2 – References

Abpmer.net 2011 www.abpmer.net [Accessed 10th October, 2012]

Halcrow 1988. Anglian Coastal Management Atlas, Sir William Halcrow & Partners

Haskoning, 2010. North Norfolk Shoreline Management Plan. Environment Agency

Mouchel 1996. North Norfolk Shoreline Management Plan. Environment Agency

SANDS software by Halcrow Group Plc. http://www.halcrow.com/sands

Steers, J A, 1981. Coastal Features of England and Wales. Eight Essays, Oleander Press, Cambridge 206 pp.