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Unit 1 Section B - Managing coastal areas

Page history last edited by K J Hutchinson 9 years, 9 months ago

Lesson 1 - Hard engineering methods (1/2)

 

Learning objectives:

- to be able to define 'hard engineering'

- to know what a groyne is, how it works and how much it costs to build

- to be able to identify the updrift and downdrift sides of a groyne on a map and an aerial photo

- to appreciate that groynes have knock-on effects of other parts of the coast

- to know what a revetment is, how it works and how much it costs to build

- to be able to identify revetments on maps and oblique aerial photos

- to know what a sea wall is, how it works and how much it costs to build

- to be able to identify a sea wall on a photograph

 

Hard engineering reduces the energy of breaking waves by building big structures between the sea and the land, or by building breakwaters that force the waves to break before they reach the beach. 

 

We covered groynes in Section A of the course. Remember that they are an example of hard engineering. Groynes cost about £5000 each. They trap sand, widening the beach. The beach then absorbs the power of the waves.

 

Here is a time-lapse video of a timber groyne being built at Portsmouth in Autumn 2008.

 

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A problem with groynes is that they starve downdrift locations of much-needed beach material, making them more susceptible to erosion. Make sure that you know how to identify the updrift and downdrift sides of the groyne in photos and on maps. The updrift side has more material on it - this is where the sediment is trapped and prevented from continuing its journey along the coast. Look at the map and photo of Mappleton below and make sure yoiu can identify the direction of longshore drift.

 

      

 

Revetments are sloping structures of wood or rock. They are built parallel to the coastline and they absorb the power of the advancing waves before they reach the cliff face.

 

 

Beach material that is flung against the revetment by the swash of the waves can go through the gaps in the structure. It then stays on the upper beach, above the revetment, acting as a further protection for the cliffs. Revetments cost approximately £2000 per metre to build. They need to be replaced regularly.

 

The revetment in the photo below is at Happisburgh in Norfolk. You can identify this revetment on a map of the area as it is shown as a straight black line running parallel with the coastline. Don't confuse it with the groynes which run at right angles to the beach.

                 

 

Sea walls are reinforced concrete structures that create a rigid barrier between the sea and the land. They are incredibly expensive to build - about £5000 per metre. Sea walls can be straight or have a curve at the top. This sends the energy of the waves back out to sea and is sometimes called a splashback.

 

 

Make sure that you can identify the sea wall on this photograph from Ventnor, Isle of Wight.

 

 

Useful weblinks:

A great description of the coastal management techniques with photos, videos and a summary table showing advantages, disadvantages and costs

S-Cool A-level site about coastal management - includes useful interactive activity

S-Cool GCSE site about coastal management strategies

 

Lesson 2 - Hard engineering methods (2/2)

 

Learning objectives:

- to know what rock armour (rip-rap) is, how it works and how much it costs to build

- to know what gabion cages are, how they work and how much they cost to build

- to know what tetrapods are, how they work and how much they cost

- to know what an offshore breakwater is, how it works and how much it costs to build

- to appreciate why some people think that hard engineering methods are not very environmentally friendly

 

Rock armour (which is also known as rip-rap) is another form of hard engineering. Large rocks are put at the foot of the cliff, or in front of a sea wall, to reduce erosion by absorbing the power of the incoming waves. They also help prevent materials from being scoured from the beach by the backwash as the water is slowed down when it runs through the gaps between the rocks, reducing its power. Rock armour costs about £3000 per metre.

 

 

Rock armour is often made from granite boulders. Many of the rocks used along the Norfolk coast have been imported from Norway, which significantly increases the cost of building the defence. The photo above was taken at Overstrand on the North Norfolk coast.

 

Gabion cages (or just gabions) are steel cages filled with rocks. They are placed in front of cliffs, often stacked one on top of another, to reduce erosion and prevent cliff falls. They absorb the power of the incoming waves and prevent the cliff from slumping forwards. Gabions cost about £100 per metre, so they are much cheaper than many of the other types of hard engineering.

 

 

 

Tetrapods are a relatively new form of coastal defence. I had seen them before but hadn't known what they were called until I started doing the research for this page! The tetrapod's shape is designed to dissipate the force of incoming waves by allowing water to flow around it rather than against it. Tetrapods interlock randomly. They remain stable even in storms.

 

 

Offshore breakwaters are usually made from large rocks. They are built up into offshore bars to make waves break before they reach the beach. As well as absorbing wave energy, they can change the direction of longshore drift. The rocks must be large so that they are not moved by storms. They cost about £2000 per metre to build. The photo below shows offshore breakwaters in Sea Palling in Norfolk.

 

 

In general, hard engineering methods are very effective in protecting the coast. However, they are expensive and are not always visually attractive. They can also prevent people from accessing the beach, and destroy natural habitats and ecosystems. Many people think that they are not environmentally friendly.

 

 

Useful weblinks:

A great description of the coastal management techniques with photos, videos and a summary table showing advantages, disadvantages and costs

S-Cool A-level site about coastal management - includes useful interactive activity

S-Cool GCSE site about coastal management strategies

St Ivo School worksheet summarising the advantages and disadvantages of the different types of coastal management

 

Lesson 3 - Hard engineering along the Holderness Coast

 

Learning objectives:

- to develop a case study of how a range of hard engineering methods are used to manage coastal erosion the Holderness Coast

 

The Holderness coastline runs from Flamborough Head to Spurn Point on the east coast of England. It is shown on the map below. It is 61 kilometres in length, and is the fastest-eroding coastline in Europe. On parts of the Holderness Coast, the rate of erosion is as much as 8mm each day. This soon mounts up - it is equivalent to almost 3 metres every year.

 


View Larger Map

 

It is estimated that the coastline has retreated by over 400 metres during the last 2000 years. In the last 1000 years, 30 coastal villages have been swept into the sea. These villages disappeared before there were any coastal defence measures. An article in the Yorkshire Post on 1st March 2007 claimed that nearly 70 houses were currently under threat on the Yorkshire coast. Their total worth was approximately £5 million.

 

                   

 

The prevailing wind is from the north-east. Most of the cliffs along this coastline are soft so they erode very easily. They are made from boulder clay - material that was eroded by glaciers during the last Ice Age and dumped on top of underlying rocks. Boulder clay is unconsolidated, which means it has a texture that is more like soil than rock (see photo below). It is very easily eroded by the incoming waves. The cliffs are especially vulnerable after heavy or prolonged rainfall - as we already know from our case study of the Holbeck Hall Hotel in Scarborough (just a few kilometres further north). Most of the eroded material is carried out to sea as fine mud, but a substantial amount is carried south by the process of longshore drift.

 

       

 

Some of the towns and villages along this coastline have been protected, and some have not. This lesson focuses on the hard engineering methods that have been used along the Holderness coastline.

 

Hornsea

The small town of Hornsea is between the towns of Bridlington and Withernsea. It is a high-density urban area with many tourist attractions. The economy is based largely on tourism. Hornsea has been protected by building wooden groynes and a concrete sea wall. These defences were first built in the early 1900s and they have been well-maintained over the years, so the location of the coastline here has changed very little over time. Recently, a rock revetment has been built to the south of Hornsea. This helps protect the caravan park.

 

 

Mappleton

Mappleton is a small village of about 50 properties 4 kilometres to the south-east of the town of Hornsea. It has experienced very rapid erosion over the years. As a result, the main coastal road is only 50 metres from the cliff edge at its closest point. A rock groyne and some rock armour was built in Mappleton in 1992. Granite was shipped in from Sweden and unloaded onto the beach to build the armour and groyne at a cost of almost £2 million. The groyne aims to keep material on the beach in front of the cliffs by stopping longshore drift. It has been quite an effective defence (look at the how to see how much wider and deeper the updrfit side of the beach is), but there have been knock-on effects further along the coast where the beaches are being starved of material that they used to receive through longshore drift. The rock armour aims to stop the waves from crashing onto the cliffs, thereby protecting the B1242 coastal road.

 

     
View Larger Map

 

Withernsea

The town of Withernsea is about 16 kilometres north of Spurn Point. It is where the B1242 meets the A1033. The beach is made up of sand and shingle and it is protected by a series of wooden groynes. The cliffs are protected by a concrete sea wall. rock revetments and rock armour. The central section of the Withernsea seafront is protected by the concrete seawall, rock armour and a rock groyne. At the north and south ends, there are concrete revetments and a small amount of rock armour. There is a substantial amount of rock armour to the south of the town. Anthony Bennett (Internet Geography) has produced this superb Google Map tour of the area with photos and captions to show the main features of coastal defence at Withernsea.

 


View Withernsea in a larger map

 

Useful weblinks:

Yorkshire Post article 1st March 2007

Internet Geography - video, photos and commentary about the town of Hornsea and its defences

Internet Geography - resources about Mappleton

Internet Geography - resources about Skipsea

Internet Geography - resources about Withernsea

A superb set of images from Andrew Stacey, taken during his trip to the Holderness Coast in March 2002 and April 2008

BBC Class Clips - Konnie Huq on the Holderness Coast (2000) showing how soft and vulnerable the boulder clay is

Sue Earle, from Cowden, talks about erosion rates to the south of Mappleton

BBC Class Clips video interviews farmers who think that increased rates of erosion to the south of Mappleton are linked to the construction of the rock groyne

A superb summary of the management strategy in 2009 - with exam style questions to work through

 

Lesson 4 - Soft engineering methods (1/2)

 

Learning objectives:

- to be able to explain why beaches are a good defence against storm waves and coastal erosion

- to be able to define the term 'soft engineering'

- to be able to define beach replenishment, recycling and reprofiling

- to know how beach replenishment, recycling and reprofiling work

- to develop a case study of how beach replenishment has been used at Pevensey Bay in East Sussex

- to know how the use of GPS systems has helped to protect the beach at Pevensey Bay

 

Beaches are a superb defence against storm waves and coastal erosion as they absorb the power of the breaking waves. Having a wide beach can also protect from the threat of coastal flooding.

 

Beaches are a depositional landform and can be made of sand, shingle or pebbles. Beach material is usually very well sorted - this means that most of the material on a particular beach is of a similar size - so sand beaches usually have very little shingle, and shingle beaches usually have very little sand. The larger the material is, the steeper the beach will be.

 

Soft engineering is where beaches (or naturally formed materials) are used to control, reduce or redirect erosion processes. Soft engineering options are often less expensive than hard engineering options. They are usually also more long-term and sustainable, with less impact on the environment, as they work with natural processes rather than against them.

 

Beach replenishment (sometimes called beach nourishment) is an example of soft engineering. Beach replenishment means that sand is dumped or pumped from elsewhere onto the beach.

 

Beach recycling is an attempt to even out the natural process of lonsgore drift. You could think of it as being the opposite of longshore drift - sand and shingle is moved from areas where it has built up from longshore drift and put back to its original position. It is most common for beach recycling to happen after winter storms when large amounts of material have been moved by natural processes.

 

Beach reprofiling happens where bulldozers are used to move material up the beach. After storms, the upper beach levels can get very low because materials have been removed in the wave backwash. Bulldozers are used to push material back up the beach to create  gently sloping profile. A gently sloping beach can absorb more wave energy than a steep beach, so it is a better natural form of defence.

 

Pevensey Bay - case study

 

Our case study for soft engineering is Pevensey Bay, a low-lying coastal area in East Sussex. Pevensey Bay's sea defences consist of a shingle bank that extends for 9km between Eastbourne and Bexhill-on-Sea in East Sussex. Immediately inland there is an area of  50 square kilometres that includes over 10,000 properties, several caravan parks and important road and rail links. It is also home to the ecologically sensitive Pevensey Levels, which would be inundated by salt water every high tide if the defences were permanently breached.

 

The Pevensey Levels are an environmentally protected area. As a result, hard engineering methods such as seawalls cannot be used to control erosion in the area as they would be too environmentally damaging. Soft engineering is used to manage the beach instead to prevent the levels from the being flooded.

 

Longshore drift moves about 25,000 cubic metres of beach material along the beach at Pevensey Bay each year. To replenish the beach, this material is replaced through a number of projects.

 

Over 40,000 compressed car tyres have been buried under the beach to provide a stable base for the replenishment of the beach. This helps to reduce the volume of beach replenishment material that is needed, and it is also a good way of recycling old tyres!

 

 

The drift direction on the beach at Pevensey is west to east, so materials are taken from the east and recycled to the west to counteract the natural drift direction. Groynes have been built on the beach to reduce this natural movement. They are made from plastic materials rather than tropical hardwood. 5,000 cubic metres of sand and gravel are taken from further west at Cooden and driven by lorry to be dumped onto the beach at Sovereign Harbour in Pevensey Bay. The photos below show how the shape of the beach changes with the recycling.

 

 

20,000 cubic metres of shingle is taken from the seabed and sprayed back onto the beach using a special ship. Layers of sand and gravel are sucked from the seabed by the dredger Sospan Dau and delivered to the beach over high tide. The dredger comes very close to the beach and discharges a mixture of sediment and water using a technique known as rainbowing. The material is taken from the seabed at Owers Bank, a few miles offshore from Littlehampton, and sprayed back onto the beach to replenish it in the area of Sovereign Harbour's rock revetment in the north harbour.

 

            

 

This video is of the Sospan Dau in action at nearby Seaford beach.

 

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Bulldozers are used after winter storms to create a more gently sloping beach profile.

 

 

Beach monitoring through Global Positioning System (GPS) surveys is very important. By comparing different surveys, replenishment, reprofiling or recycling can be targeted to when and where it is most needed. Using a GPS receiver mounted on a quad bike, surveys are carried out over the whole frontage using either one or two low tides. The receiver calculates the position of the quad bike from the satellite signals and stores them for processing once back in the office. After processing the data a 3D model of the beach surface is created from which changes in beach volume is calculated. An example is shown below. 

 

 

You should read through the official Pevensey Bay Project website for further details about the scheme. The site includes a news section so that you can follow the work done on the beach throughout the year.

 

Useful weblinks:

Pevensey Bay Project official website - section on beach recharge

Pevensey Bay Project official website - section on beach recycling

Pevensey Bay Project official website - section on shingle transfer (bypassing)

Pevensey Bay Project official website - section on reprofiling

Using GPS to monitor the beach at Pevensey

 

Lesson 5 - Soft engineering methods (2/2)

 

Learning objectives:

- to be able to define the process of managed realignment

- to be able to explain the advantages and disadvantages of managed realigment

- to explain the role of earth bunds in managed realignment

- to develop a case study of managed realignment at Wallasea in Essex

 

Managed realignment (also known as managed retreat) means that the land is allowed to flood until it reaches a new line of defence inland. This defence may be natural (eg. a ridge of higher land) or built. This is shown in the animation below (wait until the 'Existing hard flood defences' statement at the top of the list is highlighted in green for the start of the animation; the picture changes to reflect the highlighted text on the right hand side of the image). Note that if there is no natural ridge of earth, an earth bund may be constructed. This is a mound of earth that is built to separate freshwater from saltwater.

 

 

Managed retreat is often the policy where existing sea defences are allowed to fail. The sea floods the land behind the breached defences, but builds up its own natural defences such as mudflats, marshes and beaches. This can only really work where population density is low and there is little infrastructure to protect. It is seen as being a much more sustainable way of the managing the coastline than using hard engineering methods. It can also be much cheaper than hard engineering projects.

 

Managed retreat is well suited to low-lying, saltmarsh environments, for example the estuaries of Essex and Suffolk. Over time, the broad tidal marshes will help absorb and reduce wave energy, providing a low-cost coastal defence. They also enhance the ecosystem.

 

A problem with this form of management is that good quality agricultural land may be lost. Settlements and property along the coastal strip may also be destroyed. Coastal blight occurs where the price of properties in an area subject to managed retreat falls signficantly, meaning that homeowners may find themselves in negative equity and unable to afford the cost of a move inland. There have been reports of properties in the village of Happisburgh, North Norfolk being valued at just £1 due to the policy of managed retreat being proposed for the area.  

 

The Wallasea Wetlands Creation Scheme, Essex

 

Wallasea Island is on the Essex coastline. It is between two estuaries - the River Crouch and the River Roach. In the past, the area was protected by a sea wall, and the land behind the wall was used for farming. However, due to lack of repairs to the wall on the north shore over a long period of time, it was in very poor condition. By 2004. it had begun to collapse in several places. There was a high risk that the walls would fail resulting in flooding the island and causing damage to the estuary.

 

 
View Larger Map

 

It was decided that rebuilding the existing sea wall was not worthwhile. It would be very costly, and rising sea levels would put other areas at risk of flooding as the water was funnelled elsewhere. The agricultural land behind the wall was poor quality and there were very few buildings in the area. As a result, managed retreat was proposed for the northern bank of the island. The project involved several elements:

 

(a) building a new sea wall inland of the existing coastline (the sea wall is 4 km long as was build over 4 km behind the existing line of defence))

(b) building an earth bund to separate freshwater from saltwater

(c) building seven artifical islands to provide nesting places for birds, using materials excavated during the building of the London Crossrail project

(d) pumping 700,000 tonnes of mud onto the area to create a new salt marsh

(e) flooding the new area naturally when the old sea wall was breached (this happened in July 2006) to take the pressure off other locations further inland

 

 

 

The project was completed at a cost of £7.5 million on 4th July 2006 when a 300 metre section of the old sea wall was bulldozed to allow the sea to flood the area at high tide. You can see a video clip of the breach by clicking on the link below. The wetlands area covers about 115 hectares. The volume of water entering the site on each tide ranges from 790,000 cubic metres on a neap tide to 1,700,000 cubic metres on a spring tide. It is expected that by 2011, the area will have naturally evolved into a wetland, lagoons and mudflats.

 

Useful weblinks:

BBC Class Clips video about managed realignment on the Humber Estuary

Abbots Hall Farm - home of the Essex Widlife Trust - case study of managed retreat

Abbots Hall Farm - downloadable leaflet

Coastal Futures leaflet - Don't bank on it: the economics of managed realignment

Eastern Daily Press article 7/7/08 - Norfolk house valued at just £1

Photo map of the Wallasea Project

BBC News article about the breach at Wallasea in June 2006

Channel 4 video news report 'Let it flow' about the breach at Wallasea in 2006

 

Lesson 6 - How is the coastline managed in England and Wales?

 

Learning objectives:

- to consider why we need to protect the coast

- to know how the coastline is managed in England and Wales

- to know what a sediment cell is and how it is used in coastal management

- to know what a Shoreline Management Plan (SMP) is, what it might contain and how it is used

- to know DEFRA's coastal management criteria

- to be able to define the key terms 'hold the line', 'advance the line', 'managed realignment' and 'no intervention'

 

Over 4 billion people worldwide live in coastal areas, and they are also used heavily by industry. There is a growing threat of flooding due to sea-level rise, and erosion is increasing. As a result, many areas of coastline are now being protected. Coastal environments can provide unique habitats for wildlife, and so the challenge is to find ways of balancing the competing needs of people, wildlife and the environment. 

 

In England and Wales, the Department for Environment, Food and Rural Affairs (DEFRA) is responsible for protecting the coastline from both flooding and erosion. DEFRA has divided the coastline into 11 sections to make the management process easier. These areas are called sediment cells. The boundary of each of the sediment cells is usually a natural feature like a major headland or a river estuary. For example, Flamborough Head is the boundary between sediment cells 1 and 2 and the Thames estuary is the boundary between sediment cells 3 and 4. Each sediment cell is relatively self-contained as far as the movement of sand or shingle is concerned, so the actions taking place in one sediment cell would not be expected to have a significant effect on other cells.

 

Each of the sediment cells is divided into smaller areas called sub-cells. This help DEFRA to plan coastal management. It is not possible to protect the whole coastline (it would be far too expensive to do so), so DEFRA has to decide which parts to protect and which to leave alone. It does this by working at the sub-cell scale. Each sub-cell has a Shoreline Management Plan (SMP), a document that sets out a strategy for the defence of the sub-cell's coastline.  It will outline how the coastline is likely to change over the next 100 years, taking account of existing sea defences. The SMP will take into account the coastal processes operating in the area (eg. erosion, longshore drift, deposition), human needs (eg, protection of property and communities) and environmental needs (eg. protecting environmentally sensitive areas) as well as financial costs of management. SMPs are very lengthy documents! You can see a summary of the South Foreland to Beachy Head SMP by following the link in the list below.

 

Each SMP may propose management of the sub-cell in a number of ways (which our exam board calls the DEFRA coastal management criteria):

 

Hold the line - maintain the existing coastline by building defences

Advance the line - build new defences seaward of the existing defences

Managed realignment - allow the land to flood, and construct a new line of defences landward of the existing coastline

No intervention - allow natural processes to shape the land

 

The map below shows the policies set out for sub-cell 11c.

 

 

Useful weblinks:

South Foreland to Beachy Head SMP summary leaflet

Defend Our Coast Association (DOC) website - a group of residents arguing against managed retreat at Romney Marsh

 

Lesson 7 - Managing the North Norfolk Coast

 

Learning objectives:

- to examine the SMP for sub-cell 3b in North Norfolk

- to consider why some areas are protected from coastal erosion but others are not

- to develop a case study of coastal management in Sea Palling

 

North-East Norfolk has a coastline of about 70 kilometres. Much of this is boulder clay cliffs which, as you saw in Lesson 3, are very susceptible to erosion. In some places, the coastline has retreated by as much as 30 metres a year. This section focuses on the SMP for sub-cell 3b, which runs east of Kelling Hard to Lowestoft Ness. This includes the villages of Bacton, Happisburgh and Sea Palling.

 

      

 

The SMP for sub-cell 3b has recently been reviewed in partnership with Great Yarmouth Borough Council, Waveney District Council and the Environment Agency. The partners involved in this project are all members of the East Anglian Coastal Group. This plan has attracted a lot of attention from the media because it proposes a management regime of exposing large areas of cliffs to increased rates of erosion and (in the longer-term) allowing large areas of low-lying land to flood.

 

A revised plan has been prepared by North Norfolk District Council. This plan sets out conditions for the acceptance of the SMP. It states that the Council will only fully agree to and adopt the SMP when various conditions have been met. In summary, these conditons are that the Government puts in place acceptable measures, including financial support, to mitigate the effects of coastal change and makes it a requirement for a wider economic analysis to be undertaken on those frontages where it is proposed that the defence policy is to change from hold the line. Meanwhile, the Council will continue to implement the 1996 policies so far as it is able until acceptable adaptation measures have been put in place. They have agreed to invest £2 million to maintain the defences for certain key areras of the shoreline, effectively extending the life of the defences for 10 years to buy time for measures to be put into place to help the areas affected adapt to changes.

 

The sub-cell is broken into different sections, and different policies are proposed in different zones. Key locations are shown on the Google Map and there is a summary table below to show some of the key policies in the short, medium and long-terms. You can download detailed maps showing the implications of these policies from the North Norfolk District Council website.

 

Location Short term to 2025 Medium term to 2055 Long term to 2105
Weybourne Allow retreat through no active intervention Allow retreat through no active intervention Allow retreat through no active intervention
Sheringham Hold the line (maintain/replace existing defences) Hold the line (maintain/replace existing defences) Hold the line (maintain/replace existing defences)
Cromer Hold the line (maintain/replace existing defences) Hold the line (maintain/replace existing defences) Hold the line (maintain/replace existing defences)
Trimingham Allow retreat through no active intervention Allow retreat through no active intervention Allow retreat through no active intervention
Bacton Gas Terminal Hold the line (maintain existing defences) Hold the line (maintain/upgrade existing defences) Allow retreat through managed realignment
Happisburgh Allow retreat through no active intervention Allow retreat through no active intervention Allow retreat through no active intervention
Sea Palling Hold the line whilst studies are ongoing Hold the line whilst studies are ongoing Hold the line with a view to managed realignment

 


View Sub-cell 3b in a larger map

 

Coastal management at Sea Palling

 

As stated above, the SMP proposes holding the line at Sea Palling by maintaining existing defences whilst studies into the area are ongoing. This is with a view to managed realignment in the long term.

 

So what are the existing defences at Sea Palling?

 

Following some of the worst storms in the history of the East Coast, a seawall was built at Sea Palling in 1953 to protect inland areas from flooding. It was to work alongside a wide sandy beach, which would absorb much of the power of the waves. However, by the 1990s, most of the beach had been washed away so the seawall was being directly attacked by the waves during storms. In order to protect the seawall, 100,000 tonnes of boulders were places in front of the sea wall as rock armour. These were imported from Scandinavia. 1,000,000 cubic metres of sand were also brought in and dumped on the beach (beach replenishment) and four offshore reefs were built parallel to the coast using huge granite boulders. The offshore reefs break the waves before they reach the beach and the absorb their energy. Sediment is trapped on their landward side, creating a wide beach which is then very effective in absorbing wave energy. The reefs worked so well that a second set was added later (to the south of Sea Palling). You can see the impact of the reefs in building up the beach very clearly on an OS map or on an aerial photograph.

 

       

 

Useful weblinks:

East Anglian Coastal Group

North Norfolk District Council website - detailed maps showing SMP policies and their implications

A non-technical summary of SMP for North Norfolk

 

Lesson 8 - The story of Happisburgh

 

Learning objectives:

- to know the history of coastal protection in Happisburgh

- to consider why Happisburgh is no longer being protected from coastal erosion

 

Happisburgh is a village with a population of about 1400 people in about 600 houses. This is one of the fastest eroding coastlines in Europe, and thousands of tonnes of cliff material are washed away every winter. It has been estimated that the Happisburgh cliffs are now retreating at a rate of 10-15 metres every year. More than 30 buildings have been lost so far.

 

  

 

In 1959, timber sea defences were constructed between Ostend and Cart Gap, including along the front at Happisburgh. These were wooden revetments and groynes. They worked very well for a number of years, but started failing in the 1980s due to lack of maintenance and repair. As a result, the soft boulder clay cliffs took a severe battering from the waves.  By 1989, North Norfolk District Council identified the need for a major investment in new defences. Local government is responsible for repairs and upkeep of sea defences, but any capital scheme such as renewal of existing defences or creation of new ones requires the acceptance, approval and funding of central government.

 

             

 

In 2000, the Ministry of Agriculture, Farming and Fisheries (the body in charge of coastal defence at the time) agreed to fund a study of the coast between Ostend and Cart Gap to investigate the coastal processes and if possible to develop a strategy to renew the defences. A report and scheme was advertised in December 2001 recommending a 3-stage approach, starting with the construction of a rock groyne at the south end of Beach Road. Objections were received from Professor Clayton and Lord of the Manor Eric Couzens. Despite 325 letters of support, it was not possible to progress the scheme until these objections had been resolved. While the scheme was tied up in red tape at Whitehall, the sea continued its erosion at a rate far in excess of any forecasts. The end result was that in December 2002 the scheme was withdrawn as it no longer met financial or technical criteria. The diagram below shows the outline of the scheme.

 

 

North Norfolk District Council recognised that this was an emergency situation and they provided funding for 4000 tonnes of rock to be placed at the toe of the cliff as rock armour to give some short term protection. The Council emphasised that this was only intended as a temporary measure, and was not expected to withstand anything other than normal weather conditions.

 

         

 

The 2006 SMP proposes that Happisburgh is no longer protected from erosion. This is partly because the financial costs of protection are very high in relation to the value of property in the village, and partly because the eroded material from the cliffs at Happisburgh forms the beach sediment that is so vitually needed to protect downdrift locations from erosion.

 

                                

 

Since the SMP was published, local people have taken part in fundraising to extend the existing rock armour. An appeal was launched by the charity Coastal Concern in 2007 to increase the £200,000 about to be spent by the Council on emergency works at Happisburgh. This included a website for public donations - Buy a Rock for Happisburgh. Within a few months they presented £47,500 to the Council, funding around 1000 tonnes of additional rock (about at extra 25%) to be placed on the beach.  

 

BBC Britain from Above visited Happisburgh in 2008 to tell its story. You can view the episode below.

 

 

Useful weblinks:

Coastal Concern Action Group website - a very regularly updated website which has photos, press articles and commentary on the SMP - well worth a vsiit!

High altitude aerial photos showing the rate of cliff retreat in Happisburgh

Diary of events in the coastal defence history of Happisburgh

Buy a Rock for Happisburgh campaign website

 

Lesson 9 - Conflict in North Norfolk

 

Learning objectives:

- to consider how the decisions about how to manage the Norfolk coast have affected different groups of people, focusing on Sea Palling and Happisburgh

- to consider what can be done to help the community at Happisburgh - what the community area asking for, and how this could be provided

 

The video, 'Cliffhanger', by Anne O'Connell, tells the story of Happisburgh through the eyes of Di Wrightson, owner of the Cliif House tea-shop, and Clive Stockton, local councillor and landlord of the village pub. It is a superb summary of the way in which people have been affected by erosion along this stretch of coastline. Unfortunately, it would not embed in the Wiki, so you will have to click on the image to be taken to the Babelgum website to view the film.

 

 

Since the publication of the 2006 SMP, Happisburgh has suffered serious coastal blight. The local newspaper, The Eastern Daily Press, has published many articles about the falling cost of homes on this coastline. Perhaps one of the most memorable is that of the bungalow 'Arcadia' on Beach Road which has recently been valued at just £1 by Natwest and even made it into the London press! Click on the link below to view the article on the This is London website.

 

     

 

Feeling in the Happisburgh community is very strong, with many residents having bought their properties when the policy was to hold the line. The Happisburgh Singers have sent their own message to the government - you can hear this below:

 

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Locals have named the bay that has formed to the south-east of the headland at Beach Road 'DEFRA Bay' to reflect that they believe to be the causes of the rapid rate of retreat. Indeed, this bay appears to have formed where the line of revetments ends, suggesting that renewing revetments might buy Happisburgh extra time.

 

     

 

People have very different opinions about managing erosion along this stretch of coastline. Have a look at the discussion board on the CCAG website and you will find plenty of evidence of different views! You could add your own thoughts to the discussion if you wish. Some of the most frequently voiced opinions are summarised below:

 

- How can it be fair to spend £60 million on defending Sea Palling whilst Happisburgh is left to erode?

- When we bought our house on Beach Road in Happisburgh, the government policy was to hold the line. Now it has changed and my property is worthless. I can't afford to move, and no council accommodation is available. I've paid taxes all my life and I feel we should be being protected here at Happisburgh.

- Happisburgh has a thriving community - a school, a shop, a Post Office, a pub and places where people work. It is a sustainable community so it should be protected.

- There are many historic buildings in Happisburgh and they should be protected so that generations in the future can see them.

- We must protect the Norfolk Broads as they are a unique ecosystem. That means we need to spend money on protecting Sea Palling. We can't afford to protect Happisburgh too.

- The value of property in Happisburgh is low. It vwould cost more to defend it than the cost of the property. It's a different story at Sea Palling which is a vibrant economic community with shops, businesses and so on. If it must be a choice between the two, the value of the assets at Sea Palling is much higher! 

 

Malcolm Kerby, of CCAG, has argued that the arguments for restoring natural processes along this stretch of coastline do not make sense. He argues that as the composition of Happisburgh's cliffs is mostly mud, the sediment supply from the cliffs at Happisburgh is of very little or no benefit to longshore drift rates of the North Norfolk coast. His research shows that the natural flow of sediment is along a strip, or river, approximately 1 kilometre wide from the cliffs out to sea and that protection measures at Happisburgh are unlikely to affect this flow to any degree. He also argues that the Happisburgh coastline can hardly be described as behaving naturally given that there is a 4 kilometre seawall to the north and an 11 kilometre seawall to the south, not to mention the reefs and all the other defences nearby.

 

What do the people of Happisburgh want?

 

Over time, the people of Happisburgh appear to have resigned themselves to the fact that the village will not be defended. Those whose property is affected want compensation. They have argued that compensation should be paid for total loss of property due to failure to defend against coastal erosion on a coast that had been defended in the past, at current ‘no risk’ market value.

 

In June 2009, the press reported on DEFRA's work on a compensation package. This was opened to public consultation for 3 months. However,  the suggested figures look to be limited to a maximum of £1,000 to cover removal costs and redirection of post and up to £5,000 to cover knocking down the threatened property in areas of coastal erosion. Payments would not extend to covering the value of homes, even if they had been previously defended and were now subject to damaged or removed sea defences, as has happened at Happisburgh.

 

The North Norfolk District Council have refused to fully adopt the SMP until these issues can be resolved.

 

Useful weblinks:

CCAG website discussion board

CCAG website - section on 'What do we want?'

Geography All the Way - Interactive activity using a Google Map - think about how different people feel about coastal erosion and protection

BBC video - Home-made coastal defences land man in court

Article about the Arcadia bungalow valuation in This is London

 

Lesson 10 - Managing fragile coastal environments

 

Learning objectives:

- to understand why some coastal environments are under threat

- to be able to describe and explain the threats to coral reefs

- to develop a case study of how coral reefs have been managed using the example of the Great Barrier Reef Marine Park Authority in north-east Australia

 

Coastal areas have become increasingly under threat in recent years. Climate change is having a huge effect on coastal areas, making them much more susceptible to flooding. Pollution is also having a negative effect on the coastline, as is development of economic and industrial activities, particularly coastal tourism.

 

Coral reefs are an example of a marine ecosystem - one that is found in water rather than on the land. Coral reefs have been in the news recently because they have been identified as an ecosystem that is being damaged by human activity. It has been estimated that over half of the world's coral reefs have been damaged by human activity and that they could become extinct within 40 years if they are not protected and managed sustainably. According to research conducted by the University of North Carolina, coral reefs in the Indo-Pacific are disappearing twice as fast as tropical rainforests.

 

The red dots on the map show the location of the world's coral reefs. The majority are between 30 degrees north and south of the equator.

 

   

 

Coral reefs form in warm, shallow, clean seas. The sea temperatures must be above 21 degrees for coral to form, and because they need sunlight to grow, the coral must not be more than 30-40 metres from the sea surface. They are made of animals called stony corals. Corals are made up of tiny organisms called polyps. The polyp sits inside a calyx, or cup, made of limestone (calcium carbonate). As the polyps live, reproduce, and die, they leave their skeletons behind. A coral reef is built up by layers of these skeletons covered by living polyps, which are further cemented together by organisms like coralline algae, and physical processes like waves washing sand into spaces in the reef. Researchers may look at the amount of living coral on a reef to determine how healthy it is.

 

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There are 3 types of coral reefs:

 

  • Fringing reefs, which grow close to the coast in shallow waters
  • Barrier reefs, which are large, continuous and are separated from land by a lagoon (the Great Barrier Reef is the largest example of a barrier reef)
  • Atolls, which are ring-shaped and located near the sea surface on top of underwater islands or inactive volcanoes

 

Why are coral reefs important?

 

- They provide a home and food (nutrients) for many different species of fish. Without coral reefs, these fish are left homeless with nowhere to live and nowhere to have their babies. They increase the world's biodiversity.

- Reef fish and molluscs feed between 30 and 40 million people every year.

- Reef fish make beautiful pets and the money made by catching and selling these animals provides many people with an income so that they can feed their families.

- Coral are very important in controlling how much carbon dioxide is in the ocean water. The coral polyp turns carbon dioxide in the water into a limestone shell. Without coral, the amount of carbon dioxide in the water would rise dramatically and that would affect all living things on Earth.

- Coral reefs protect coasts from strong currents and waves by slowing down the water before it gets to the shore. They provide a barrier between the ocean and the shore.

 

Destruction of the coral reefs

 

10% of the world's coral reefs have already been completely destroyed. In the Philippines, where coral reef destruction is the worst, over 70% have been destroyed and only 5% can be said to be in good condition. So what has happened to destroy the reefs?

 

 

There are two different ways in which humans have contributed to coral reef damage - indirectly and directly.

 

Indirectly, we have destroyed their environment. Coral reefs can live only within a certain temperature and salinity range. Global warming caused by the greenhouse effect has increased the temperature of the oceans so high that the coral get sick and die. Even a rise of one degree in the average water temperature can hurt the coral. The most obvious sign that coral is sick is coral bleaching. That is when either the algae inside die, or the algae leave the coral. The algae are what give coral its color, so without the algae the coral has no color and the white of the limestone shell shines through the transparent coral bodies. You can see this in the photo below.

 

 

The warmer water also encourages the growth of harmful algae on top of the coral which kills it, because it blocks out the sun. Without the sun, the zooxanthellae cannot perform photosynthesis and so they die. Without the zooxanthellae, the coral polyps die too. This algae is usually eaten by fish, but because of overfishing, there aren't enough fish left to eat all the algae. The pollution that people have dumped in the ocean is just what the algae needs to grow and be healthy, which means covering and eventually killing the coral reefs.

 

The direct way in which humans destroy coral reefs is by physically killing them. All over the world, but especially in the Philippines, divers catch the fish that live in and around coral reefs. Often they blow up a coral reef with explosives and then catch all the stunned fish swimming around. This completely destroys the reefs, killing the coral polyps that make it as well as many of the plants and animals that call it home. The creatures that do survive are left homeless. Corals may also be blasted to get stone to build houses.

 

Tourism is also having an effect. Illegal collection of coral for souvenirs is becoming a major threat. Huge numbers of hotels, restaurants and bars have been built for the tourists and all of the waste water finds its way into the sea. In heavy rain, the drainage and sewage systems cannot work effectively and filthy water pours into the sea. Oil from cruise ships carrying tourists may also leak into the sea, adding to pollution levels and blocking sunlight from reaching the reefs.

 

              

 

President Bill Clinton was aware of these threats and said the following: "Pollution, overfishing, and overuse have put many of our unique reefs at risk. Their disappearance would destroy the habitat of countless species. It would unravel the web of marine life that holds the potential for new chemicals, new medicines, unlocking new mysteries. It would have a devastating effect on the coastal communities from Cairns to Key West, Florida -- communities whose livelihood depends upon the reefs."

 

Managing the coral reef - The Great Barrier Reef Marine Park Authority

 

The Great Barrier Reef is the largest coral reef in the world. It is made of over 2900 individual reefs and 900 islands stretching for over 3000 kilometres. It is in the Coral Sea, which lies off the coast of Queensland in North-East Australia. The Great Barrier Reef is so large that it can be seen from outer space. It was selected as a UNSECO World Heritage Site in 1981.

 

                          

 

The Great Barrier Reef Marine Park is a multiple-use area. It covers 344,000 square kilometres. Zoning helps to manage and protect the Marine Park so that all users can enjoy it, now and in the future. Zoning therefore helps to make sure that the Park is managed in a sustainable way.

 

Zoning Plans say what activities can happen where, both to protect the marine environment and to separate potentially conflicting activities. The current Zoning Plan was introduced in 2004. Watch the video to find out more about the background to the zoning plan.

 

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The Preservation Zone - the Pink Zone - is a 'no go' area. A person cannot enter a Pink Zone unless they have written permission and extractive activities (eg. removing coral or fishing) are strictly prohibited. Research may occur in a Pink Zone, if it cannot be done elsewhere, but only if the research is relevant to, and a priority for, management. A permit is required to conduct research in this zone. The Pink Zone makes up less than 1% of the Great Barrier Reef Marine Park. Pink Zones provide high-level protection for special and unique places, habitats, plants and animals within the Marine Park and provides an undisturbed baseline for comparison with other zones.

 

The Marine National Park Zone - the Green Zone - is a 'no-take' area and extractive activities like fishing or collecting are not allowed without written permission from Marine Park authorities. Anyone can enter a Green Zone and participate in activities such as boating, swimming, snorkelling and sailing. Fishing gear, such as rods with attached hooks, must be stowed inboard the boat or in rod holders. All fishing apparatus must be out of the water. Anchoring is also allowed in a Green Zone, however in high use and sensitive areas use of a mooring may be necessary or there may be a no anchoring area defined by buoys. The Green Zone makes up about 33% of the Great Barrier Reef Marine Park.

 

Green Zones protect the biodiversity within the Great Barrier Reef Marine Park by protecting important breeding and nursery areas such as seagrass beds, mangrove communities, deepwater shoals and reefs. The size of fish within no-take areas will increase and these bigger fish will produce more offspring. Adult fish and their offspring are not confined to the no-take areas and can move into adjacent areas, creating a spillover effect that helps replenish fish stocks in areas where fishing is allowed.

 

The Scientific Research Zone - the Orange Zone - makes up less than 1% of the Park. It facilitates research, in areas primarily around scientific research facilities that are relatively undisturbed by extractive activities. The Orange Zone helps to manage research activities and separates research from conflicting, high impact activities. This helps to ensure research and data gathered within the Great Barrier Reef Marine Park is less influenced by human activity.

 

The Buffer Zone - the Olive-Green Zone - makes up about 3% of the Park. It provides for the protection and conservation of areas of the Marine Parks in their natural state, while allowing the public to appreciate and enjoy the relatively undisturbed nature of the area. Trolling for pelagic fish species is allowed in the Buffer Zone. However, all other forms of extractive activities such as bottom fishing and spearfishing are prohibited in this zone. Pelagic species include species of trevally, scad, queenfish, rainbow runner, dolphinfish, black kingfish or cobia, barracuda, sailfish, marlin, swordfish, mackerel, tuna, bonito, wahoo, small toothed jobfish and green jobfish.

 

The Conservation Park Zone - the Yellow Zone - allows for increased protection and conservation of areas of the Marine Park, while providing opportunities for reasonable use and enjoyment including limited extractive use. Most extractive activities are allowed in a Yellow Zone with additional restrictions for most fishing activities. Fishing activities allowed in a Conservation Park (Yellow) Zone include:

 

- limited line fishing (one hand-held rod or one hand-held line per person, with no more than one hook attached to that line)

- trolling (no more than three lines per person and up to six hooks combined total per person)

- limited spearfishing (snorkel only)

- bait netting

- limited crabbing (four crab pots, dillies or inverted dillies)

- limited collecting (includes oysters and bait, excludes take of coral (live or dead and anemones)

 

The Habitat Protection Zone - the Dark Blue Zone - provides for the conservation of areas of the Great Barrier Reef Marine Park by protecting and managing sensitive habitats and ensuring they are generally free from potentially damaging activities. Trawling is not permitted in the Habitat Protection Zone. The Zone continues to provide for reasonable use of areas and makes up about 28% of the Great Barrier Reef Marine Park. 

 

The General Use Zone - the Light-Blue Zone - is to provide opportunities for reasonable use of the Great Barrier Reef Marine Park, while still allowing for the conservation of these areas. The General Use Zone in the Great Barrier Reef Marine Park is very similar to the Queensland (State) General Use Zone.

 

The Queensland Government manages commercial fishing in the Marine Park. The main management strategies are:

 

- limits on the number of fishing licences

- seasonal closures

- restrictions on the size of fishing boats

- restrictions on the length, mesh sizes and number of nets used

- limits on the number of hooks used

- limits on the numbers of traps such as crab pots used

- limits on the total allowable catch restrictions on the size of fish

 

Many organisations are researching the impacts of the zoning of the Marine Park. The video clips below present some of the main findings.

 

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Useful weblinks: 

Great Barrier Reef Marine Park Authority webpage about how climate change is affecting the reef 

Zoning Guide for the Great Barrier Reef Marine Park

Official Google Earth tour of World Heritage sites

reefED - Great Barrier Reef education website

Soufriere Marine Management Area, St Lucia - overview website

Go for a 'virtual dive' on a coral reef

 

 

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