Baba coastal mng.

Why is coastal management needed and what is hard engineering?

Coastal management is essential to build resilience in coastal communities around the world. Climate change, increased tropical storm intensity, more frequent storm surges and sea level change are increasing the rates of coastal erosion and flooding. These hazards need to be adapted to, as they are already happening in many places.

Preventing coastal erosion through hard engineering is generally effective but it is very expensive. Hard engineering can also often be unsightly. There are lots of different hard engineering strategies; to decide which is most appropriate in a particular area a cost benefit analysis must be carried out. Some areas are left with no protection because the costs are deemed to outweigh the benefits.

What are groynes and what are their advantages and disadvantages?

How it works: Structures built perpendicular (at right angles) to the shore. Sediment is trapped as it is transported by longshore drift. The beach builds up which absorbs wave energy.

Advantages:

· Not as expensive as other hard engineering structures

· Builds up the beach which improves tourist potential

Disadvantages:

· Causes sediment starvation further along the coast

· Can be unattractive

· Need lots of maintenance to ensure sediment isn't getting through any holes or cracks

What are sea walls and what are their advantages and disadvantages?

How it works: Walls with a curved or stepped surface that absorb and reflect wave energy.

Advantages:

· Highly effective

· Can have tourism benefits as walkways are created

Disadvantages:

· Very expensive to build and maintain - £6000 per metre

· Are ugly and intrusive to the landscape

What are rip rap/rock armour and revetments?

Rip Rap/Rock armour: Large concrete or granite boulders at the foot of a cliff. The spaces in between the boulders cause waves to bounce between many surfaces, reducing the energy of the wave.

· Advantages: Cheaper than sea walls; used for recreation such as fishing

· Disadvantages: Dangerous when people are on them; rocks from elsewhere are intrusive to local geology

Revetments: A sloped or ramp-like structure that breaks up wave energy.

· Advantages: Cost-effective compared to other hard engineering strategies

· Disadvantages: Need lots of maintenance; unnatural looking; slopes are dangerous

What is an offshore breakwater and what are its advantages and disadvantages?

How it works: Rock barrier a little out to sea from the shoreline. This breaks the waves and dissipates their energy before they reach the coast.

Advantages:

· Effective

· Away from the beach so does not disrupt tourist potential

Disadvantages:

· Can create a navigation barrier in harbour areas

What is soft engineering?

Soft engineering is different from hard engineering as it works with natural processes and material. Soft engineering methods can be an integral part of the strategy to adapt to sea level change as well as coastal erosion, such as through the development of marshes.

What are beach nourishment and cliff regrading/drainage?

Beach nourishment/replenishment: Adding sand or shingle to a beach to widen it - creates more surface area to absorb wave energy.

· Advantages: Looks very natural; bigger beaches are good for tourism; relatively inexpensive

· Disadvantages: Material is constantly subject to erosion and longshore drift so lots of maintenance and monitoring are needed; dredging the seabed can have impacts on local ecosystems

Cliff Regrading and Drainage: Reducing the angle of the cliff to stabilise the slope. Drainage of water also stabilises the cliff against mass movement.

· Advantages: Cost-effective

· Disadvantages: Can look unnatural as the cliff is unnaturally flatter; this effectively creates a cliff retreat; dried-out cliffs can collapse

What are dune stabilisation and marsh creation?

Dune stabilisation: Planting species like Marram grass so that the roots bind the dunes. The dunes absorb wave energy and protect the land behind them.

· Advantages: Cheap and sustainable; creates habitats for wildlife; maintains a natural environment

· Disadvantages: People walk on the dunes and damage them; planting is time-consuming and it takes time for plant species to become established

Marsh Creation: This is a form of do-nothing or managed retreat. The land is allowed to be flooded by the sea and then left to become a salt marsh. This absorbs wave energy and also creates a buffer to rising sea levels and protects higher-value land.

· Advantages: A cheap option; creates important and unique wildlife habitats

· Disadvantages: Agricultural land is lost which creates a need for compensation

What are Shoreline Management Plans?

The apparent negative impacts of many coastal management plans have created a need for a more sustainable and integrated approach. This means that different sections of the coastline are seen to function together rather than separated such as with more traditional methods like sea walls or groynes.

Sustainable approaches require:

· Management of natural resources at the coast like water and farmland

· Monitoring of any changes to inform new strategies

· Education and inclusion of the local communities to support the strategies

In a Shoreline Management Plan (SMP), each of the 11 sediment cells in the UK have had a detailed document written to identify the natural processes, activities and risks in the area. DEFRA (the Department for Environment, Food and Rural Affairs) makes recommendations for all sections of the coastline.

What are the four SMP recommendations?

DEFRA makes recommendations from the four options:

· Hold the line: maintaining the position of the coastline using mostly hard engineering methods

· Advance the line: extending the coastline out to sea by building up the beach and land reclamation

· Managed retreat: deliberate flooding of particular areas to manage the coastal retreat

· Do nothing: letting nature take its course

When making these recommendations DEFRA has to consider the value of the land and assets as well as the technical viability of management strategies. This can lead to local conflict because the SMP protects some areas and not others.

Example: In Skipsea on the Holderness coast, erosion rates since 1989 have been 1.4m per year on average. People in Skipsea feel that nothing has been done to protect their village with a population of 700 whilst money has been spent on coastal defences in neighbouring towns and villages. The decisions were made as a result of cost-benefit analysis.

What is cost-benefit analysis in coastal management?

This is used to decide the recommendations for each section of coastline. Costs are forecast based on known tangible costs of coastal defences such as how much 100m of sea wall will cost to build and maintain, and intangible costs such as the visual impact of the sea wall. The costs are then weighed up against the benefits for the environment and population.

Where benefits outweigh costs, such as the sea wall at Bridlington protecting a population of over 36,000 and buildings from coastal flooding, then the project is likely to go ahead. Where the costs outweigh the benefits, such as protecting the 24 houses at Skipsea from coastal erosion and flooding, a scheme is unlikely to be put in place.

What is Integrated Coastal Zone Management (ICZM)?

Large sections of the coastline are managed with one strategy. The shoreline management plans in the UK are a form of ICZM. Whole sections of the coast are managed together. They recognise that the sediment (littoral) cells interact with each other and that changes in one part of the coast impact other areas - such as the placement of groynes causing terminal groyne syndrome. In the UK this can cross political and national boundaries which means different councils have to work together.

ICZM involves a range of stakeholders involved in the use and management of the coast and aims to:

· Create sustainable economic and social activities

· Protect the coastal environment

· Manage flood and coastal erosion risk

· Resolve any conflicts that may occur

This type of management is also based on the principle that actions in one area of the coastline affect other places further along the coast. This is due to sediment flows within the sediment cell. Groynes are a good example of the opposite of this strategy as they cause the build up of sediment on one area of the coast but then starvation further down.

All stakeholders in the area must be included in the decisions within ICZM. In 2013 the EU introduced an initiative to use ICZMs on all of Europe's coastlines.

What conflicts arise from coastal management?

Any type of coastal management will create an impact elsewhere and this can create conflict. Conflicts over coastal management often arise between those considering the economic outcomes of a strategy versus the environmental outcomes. Homeowners and farmers often have strong attachments to a place so any change can cause a great loss.