Edexcel GCSE Geography B (1GB0) — UK Physical Landscapes
Every time a winter storm batters the UK coast, local councils face a multimillion-pound question: should we fight the sea, or let it win? A Shoreline Management Plan (SMP) is a large-scale report that assesses coastal risks and identifies the most sustainable management policy for a specific sediment cell. These plans evaluate intervention strategies across three future time periods, known as epochs: short-term (0–20 years), medium-term (20–50 years), and long-term (50–100 years).
To ensure long-term sustainability, councils use Integrated Coastal Zone Management (ICZM). This holistic approach coordinates the environment, economy, and society by involving all stakeholders, from local residents and business owners to environmentalists, ensuring that protecting one area does not negatively impact another.
Protecting a coastline is extremely expensive, so how does the government decide if a village is 'worth' saving? The Environment Agency uses a Cost-Benefit Analysis (CBA) to compare the economic value of the land, property, and infrastructure saved against the cost of building and maintaining defences. For context, agricultural farmland is valued at approximately £30,000 per hectare, whereas a hard engineering sea wall can cost up to £10,000 per metre to build.
Decisions are based on the Benefit-Cost Ratio (BCR). If the BCR is greater than 1, the scheme is economically viable; if it is less than 1, authorities will usually reject hard engineering in favour of a more sustainable approach.
Sometimes the best way to defend against the sea is to surrender land to it. Strategic Realignment is a sustainable approach where existing coastal defences are deliberately breached or moved inland. This allows the sea to flood low-lying land, creating natural buffer zones like salt marshes that absorb wave energy. Importantly, it prevents Coastal Squeeze, a destructive process where natural habitats are trapped between rising sea levels and fixed man-made defences.
At Medmerry in West Sussex, a 110 m gap was breached in an existing shingle bank to create 183 hectares of intertidal habitat. While the initial project cost £28 million, it was far more economically sustainable long-term than the previous £200,000 annual maintenance cost.
The social and economic impacts of Medmerry are mixed, highlighting why stakeholder perspectives differ. The scheme increased flood protection for 348 properties and the vital B2145 road to a 1-in-100 year standard, boosting green tourism. However, it resulted in the permanent loss of three productive farms, explaining why environmental groups often champion realignment while local landowners strongly oppose it.
What happens when the cost of defending a town is drastically higher than the value of the town itself? Under a Do Nothing (No Active Intervention) policy, no financial investment is made in coastal defences, allowing natural erosional and depositional processes to continue entirely without human interference. This strategy is exclusively chosen when the CBA is deeply negative.
At Happisburgh in North Norfolk, holding the line would have cost an estimated £15 million, which far exceeded the economic value of the village. Consequently, over 25 properties and a 14th-century church have either been lost to the sea or left highly vulnerable.
| Feature | Strategic Realignment | Do Nothing (No Active Intervention) |
|---|---|---|
| Human Intervention | Active breaching of old defences and building of new inland embankments. | Zero human intervention; no maintenance of any existing defences. |
| Environmental Impact | Creates new intertidal habitats (e.g., salt marshes) and boosts biodiversity. | Natural cliff erosion continues; provides vital sediment for downdrift beaches. |
| Economic Cost | High initial cost (e.g., £28 million at Medmerry) but low long-term maintenance. | Zero cost to the taxpayer (highly positive CBA for the national government). |
| Social Impact | Protects inland properties and roads from flooding. | Residents lose properties, receive no compensation, and communities are destroyed. |
Conclusion on Long-Term Sustainability: Overall, the long-term sustainability of these approaches involves significant trade-offs. 'Strategic Realignment' is generally the most sustainable holistic choice, as it balances environmental gains (habitat creation) with social protection for key infrastructure, despite high initial costs. In contrast, while 'Do Nothing' is the most economically sustainable option for the national government, it is socially unsustainable because it leads to the total loss of communities without compensation. Both are superior to hard engineering in terms of working with natural processes to prevent coastal squeeze.
To investigate the impact of coastal policies, geographers use both physical OS maps and GIS (Geographic Information Systems). On 1:25,000 or 1:50,000 OS maps, physical and human features are represented by specific symbols:
GIS allows users to overlay digital data layers to identify spatial patterns. Common layers include Environment Agency Flood Risk Zones (categorised into High, Medium, and Low risk), British Geological Survey (BGS) geology maps showing erosion-prone boulder clay, and LiDAR elevation data, which accurately maps land below 5 m contours.
By overlaying a flood risk layer onto a land-use layer, you can accurately query how many "High Risk" polygons intersect with residential areas. GIS is generally superior to paper maps because layers can be updated in real-time and allow for the precise calculation of the area of properties at risk.
Measuring how fast a cliff is collapsing is essential for predicting when coastal infrastructure will fall into the sea. Geographers calculate the mean rate of erosion by comparing historical maps with modern GIS layers. This methodology helps identify unintended consequences of management, such as Terminal Groyne Syndrome, where hard engineering protects one area but starves downdrift beaches of sediment, rapidly accelerating erosion elsewhere.
A geographer is investigating the impact of Terminal Groyne Syndrome south of a newly built sea defence. Using a historical OS map from 1909 and a modern GIS layer from 2024, they measure the distance from a fixed triangulation pillar to the cliff edge. In 1909, the distance was 450 m. In 2024, the distance is 220 m. Calculate the mean rate of erosion.
Step 1: Calculate the total distance retreated.
Step 2: Calculate the number of years between the two measurements.
Step 3: Use the formula to calculate the mean rate of erosion.
Step 4: Calculate the final answer.
Students often confuse 'Strategic Realignment' with 'Do Nothing'. Strategic realignment is an active, planned breach of defences to create a natural buffer, whereas 'Do Nothing' simply abandons defences to let nature take its course without intervention.
In an 8-mark 'Discuss' question on sustainable approaches, you must evaluate multiple perspectives and provide a balanced conclusion. Mention that 'Do Nothing' is economically sustainable for the government but socially devastating for residents.
When investigating policy impacts using OS maps, look for grey serrated lines (cliffs) to identify areas prone to erosion, and overlay these with contour lines to find low-lying land at risk of flooding.
Examiners frequently award marks for explaining WHY GIS is better than paper maps: always mention that GIS layers can be updated in real-time and allow for automated, precise calculations of flooded areas.
Shoreline Management Plan (SMP)
A large-scale report assessing coastal risks and identifying the most sustainable management policy for a designated stretch of coastline.
Sediment cell
A largely self-contained stretch of coastline where the movement of sand and shingle is governed by longshore drift and currents.
Integrated Coastal Zone Management (ICZM)
A holistic management process that coordinates the environment, economy, and society across an entire coastal section, involving all stakeholders.
Cost-Benefit Analysis (CBA)
A process used to determine if the economic benefits of protecting a coastline outweigh the financial costs of building and maintaining defences.
Benefit-Cost Ratio (BCR)
A numerical value calculated by dividing total economic benefits by total economic costs; a value greater than 1 indicates a viable project.
Strategic Realignment
A sustainable approach where existing coastal defences are breached or moved inland, allowing the sea to flood low-lying land to create natural buffers.
Coastal Squeeze
The process where intertidal habitats like salt marshes are trapped and destroyed between rising sea levels and fixed man-made sea defences.
Do Nothing (No Active Intervention)
A policy where no investment is made in coastal defences, allowing natural erosional and depositional processes to occur without human interference.
GIS (Geographic Information Systems)
Digital mapping software that allows geographers to overlay multiple layers of spatial data to identify patterns and relationships.
LiDAR
A remote sensing technology that uses lasers to generate highly accurate 3D elevation maps of the Earth's surface.
Terminal Groyne Syndrome
A phenomenon where the last groyne in a series prevents sediment from moving downdrift, causing rapid and severe erosion further along the coast.
Put your knowledge into practice — try past paper questions for Geography B
Shoreline Management Plan (SMP)
A large-scale report assessing coastal risks and identifying the most sustainable management policy for a designated stretch of coastline.
Sediment cell
A largely self-contained stretch of coastline where the movement of sand and shingle is governed by longshore drift and currents.
Integrated Coastal Zone Management (ICZM)
A holistic management process that coordinates the environment, economy, and society across an entire coastal section, involving all stakeholders.
Cost-Benefit Analysis (CBA)
A process used to determine if the economic benefits of protecting a coastline outweigh the financial costs of building and maintaining defences.
Benefit-Cost Ratio (BCR)
A numerical value calculated by dividing total economic benefits by total economic costs; a value greater than 1 indicates a viable project.
Strategic Realignment
A sustainable approach where existing coastal defences are breached or moved inland, allowing the sea to flood low-lying land to create natural buffers.
Coastal Squeeze
The process where intertidal habitats like salt marshes are trapped and destroyed between rising sea levels and fixed man-made sea defences.
Do Nothing (No Active Intervention)
A policy where no investment is made in coastal defences, allowing natural erosional and depositional processes to occur without human interference.
GIS (Geographic Information Systems)
Digital mapping software that allows geographers to overlay multiple layers of spatial data to identify patterns and relationships.
LiDAR
A remote sensing technology that uses lasers to generate highly accurate 3D elevation maps of the Earth's surface.
Terminal Groyne Syndrome
A phenomenon where the last groyne in a series prevents sediment from moving downdrift, causing rapid and severe erosion further along the coast.
