You are viewing a free preview of this lesson.
Subscribe to unlock all 10 lessons in this course and every other course on LearningBro.
Spec mapping (AQA 7037): Paper 1, §3.1.3 Coastal Systems and Landscapes — coastal management: hard-engineering approaches (sea walls, groynes, rock armour/rip-rap, revetments, gabions, offshore breakwaters); soft-engineering approaches (beach nourishment, beach reprofiling, dune regeneration, managed realignment); sustainable management — Shoreline Management Plans, Integrated Coastal Zone Management, cost–benefit analysis. Management is the human modification of the coastal system established in Lesson 1 — intervening in the sediment budget, the energy cascade and the equilibrium the course has analysed. It links synoptically to §3.1.6 contemporary issues / changing places (the social-justice and decision-making dimensions of who is protected) and to §3.1.5 Hazards (defences as risk-reduction). The dominant Assessment Objectives are AO1 (knowledge of strategies and the SMP framework) and AO2 (critical evaluation of effectiveness, cost, sustainability and equity). The cost–benefit exercise exercises AO3 (interpreting and manipulating cost–benefit and BCR data).
Why this lesson matters. Management is where everything you have learned becomes decision-relevant. The examiner's highest reward goes not to candidates who list sea walls and groynes, but to those who judge: which strategy suits which coast, why a defence that works at Bridlington starves Cowden, and whether "holding the line" is even sustainable as sea level rises. This lesson trains evaluation against explicit criteria — cost, effectiveness, sustainability, equity — which is the currency of the 20-mark essay.
Coastal management is driven by the need to protect:
However, coastal management also involves difficult decisions about where to invest limited resources and what trade-offs to accept. Not every section of coast can be protected, and protection in one area can create problems elsewhere. Three questions frame every management decision and are worth carrying into the exam: what are we protecting and is its value great enough to justify the cost (the cost–benefit question); what are the wider consequences of intervening, both down-drift within the sediment cell and for natural habitats (the systems question); and is the strategy durable as sea level rises and storminess increases (the sustainability question). A management answer that addresses all three — value, consequences and durability — rather than merely describing the engineering, is operating at the level the top band demands.
Hard engineering involves the construction of physical structures to resist or control natural processes. These approaches are typically expensive, require ongoing maintenance, and can have unintended consequences on adjacent coastlines.
| Feature | Detail |
|---|---|
| Description | Concrete or stone wall built at the base of a cliff or at the back of a beach |
| Purpose | Reflects wave energy; prevents cliff retreat and overtopping |
| Cost | £5,000-£10,000 per metre (curved/recurved walls are more expensive) |
| Lifespan | 30-50 years (requires maintenance) |
| Advantages | Effective at preventing erosion directly behind the wall; protects property and infrastructure |
| Disadvantages | Very expensive to build and maintain; reflected wave energy scours the beach in front (reducing natural protection); prevents cliff erosion that supplies sediment to the system; visually intrusive; can fail catastrophically in extreme storms |
Example: The sea wall at Scarborough (North Yorkshire) protects the town's promenade and tourist infrastructure. The original Victorian wall has been rebuilt and strengthened multiple times, most recently after storm damage in 2012, at a cost of over £7 million.
| Feature | Detail |
|---|---|
| Description | Timber, rock or concrete barriers built perpendicular to the shore, extending across the beach |
| Purpose | Trap sediment transported by longshore drift, widening the beach on the updrift side |
| Cost | £5,000-£10,000 per groyne (timber); up to £20,000 (rock) |
| Lifespan | 20-30 years (timber); 50+ years (rock) |
| Advantages | Effective at building up the beach, which provides natural wave energy absorption; relatively simple to construct |
| Disadvantages | Starve beaches downdrift of sediment (terminal groyne effect); require regular replacement (timber rots); create discontinuous beach |
Example: At Mappleton, Holderness (1991), two rock groynes and rock armour were installed at a cost of £2 million to protect 80 properties. The groynes successfully trapped sediment and built up the beach locally, but cliff erosion doubled at the unprotected village of Cowden 2 km to the south, which lost its access road and several properties.
Key Definition: The terminal groyne effect is the accelerated erosion that occurs downdrift of a groyne field, caused by the interception of sediment that would naturally have been transported along the coast by longshore drift.
| Feature | Detail |
|---|---|
| Description | Large boulders (typically granite or basalt, 5-10 tonnes each) placed at the base of a cliff or sea wall |
| Purpose | Absorb and dissipate wave energy before it reaches the cliff or wall |
| Cost | £1,000-£3,000 per metre |
| Lifespan | 20-30 years |
| Advantages | Effective at reducing wave impact; relatively cheap compared to sea walls; can use locally sourced rock; permeable (allows water to drain through) |
| Disadvantages | Visually intrusive (large, angular boulders look unnatural); can be dangerous to walk on; may need replacing after storm displacement; restricts beach access |
| Feature | Detail |
|---|---|
| Description | Wire cages filled with rocks, placed at the base of a cliff |
| Purpose | Absorb wave energy; support the cliff face |
| Cost | £50-£100 per metre |
| Lifespan | 5-10 years (wire corrodes in salt water) |
| Advantages | Very cheap; easy to install; can be effective short-term |
| Disadvantages | Short lifespan; look unattractive; wire cages can break and become hazardous; limited effectiveness against high-energy waves |
| Feature | Detail |
|---|---|
| Description | Walls of rock or concrete blocks built offshore, parallel to the coast |
| Purpose | Force waves to break before reaching the shore, reducing energy; encourage sediment deposition in the calmer water behind |
| Cost | £3,000-£5,000 per metre |
| Lifespan | 30-50 years |
| Advantages | Reduce wave energy reaching the shore; can promote beach growth in their lee (creating tombolo-like features) |
| Disadvantages | Very expensive; can alter sediment transport patterns; hazard to navigation; visually intrusive from shore |
| Feature | Detail |
|---|---|
| Description | Sloping structures built along the cliff base, typically of timber, concrete or interlocking blocks |
| Purpose | Absorb and dissipate wave energy; prevent undercutting |
| Cost | £1,000-£4,000 per metre |
| Lifespan | 20-30 years |
| Advantages | Less expensive than sea walls; permeable designs (e.g., open timber revetments) allow water to drain through, reducing wave reflection |
| Disadvantages | Require maintenance; can restrict beach access; timber rots; concrete can crack |
Soft engineering works with natural processes rather than against them. These approaches are generally cheaper, more sustainable, and more environmentally sensitive than hard engineering.
| Feature | Detail |
|---|---|
| Description | Adding sand or shingle to a beach, usually dredged from offshore or transported from elsewhere |
| Purpose | Widen the beach, increasing its capacity to absorb wave energy and protect the coast behind |
| Cost | £3,000-£5,000 per metre (initial); requires repeat applications every 3-10 years |
| Advantages | Looks natural; maintains beach amenity value for tourism; provides natural wave defence; does not disrupt sediment transport along the coast |
| Disadvantages | Expensive over the long term (sediment is continuously removed by longshore drift and storms); dredging can damage offshore habitats; nourishment sand may not match native beach material in colour or grain size |
Example: The Bournemouth Beach Management Scheme (2006-2010) involved pumping approximately 1 million m³ of sand from Poole Bay onto the beaches. The scheme cost £22 million and widened beaches by up to 60 m, significantly improving both coastal defence and the tourism economy (worth over £500 million/year to the local area).
| Feature | Detail |
|---|---|
| Description | Bulldozing existing beach material to create a steeper, higher beach profile |
| Purpose | Increase the beach's effectiveness as a wave barrier |
| Cost | £5-£20 per metre (very cheap) |
| Advantages | Very inexpensive; no imported material needed; quick to implement |
| Disadvantages | Temporary — storms quickly return the beach to its natural profile; only works with existing sediment |
| Feature | Detail |
|---|---|
| Description | Planting marram grass, installing sand fences, and managing public access to encourage dune growth |
| Purpose | Build up and stabilise sand dunes as a natural barrier against flooding and erosion |
| Cost | £200-£2,000 per metre |
| Advantages | Creates natural, self-sustaining defence; enhances biodiversity; relatively cheap; attractive landscape |
| Disadvantages | Takes time to establish (years); vulnerable to storm damage during early growth; requires ongoing management of public access (boardwalks, fencing) |
| Feature | Detail |
|---|---|
| Description | Allowing the sea to flood low-lying coastal land by removing or breaching existing defences |
| Purpose | Create new intertidal habitats (salt marsh, mudflat) that provide natural flood defence |
| Cost | Variable — can be negative cost if existing defences no longer need maintenance |
| Advantages | Creates valuable habitats; provides natural wave attenuation; sustainable long-term; can compensate for habitat lost to coastal squeeze elsewhere; potentially cheapest option |
| Disadvantages | Land is lost (agricultural, residential or other use); can be socially and politically contentious; compensation costs for landowners; may affect drainage of adjacent land; takes time for new habitats to establish |
Case Study: Medmerry, West Sussex (2013)
The Medmerry Managed Realignment Scheme is the largest open-coast managed retreat project in Europe:
graph LR
subgraph "Managed Retreat Process"
A["Existing defence (e.g., sea wall or shingle bank)"] --> B["Defence breached or removed"]
B --> C["Sea floods low-lying land behind"]
C --> D["New intertidal habitat develops (salt marsh, mudflats)"]
D --> E["Natural wave attenuation protects land further inland"]
E --> F["New defence line built inland if needed"]
end
Exam Tip: Managed retreat is a particularly strong topic for evaluation questions, as it involves clear trade-offs between economic, social and environmental factors. Be prepared to discuss why it is controversial (loss of homes, farmland, sense of place) alongside its benefits (cost savings, habitat creation, sustainability). Always reference specific case studies.
Shoreline Management Plans represent a strategic, integrated approach to coastal management in England and Wales.
Key Definition: A Shoreline Management Plan (SMP) is a non-statutory policy document that provides a large-scale assessment of the risks associated with coastal processes and presents a long-term framework for coastal management decisions.
SMPs were first introduced in 1995 following recommendations from the Ministry of Agriculture, Fisheries and Food (MAFF). The current second generation of SMPs (SMP2s), completed between 2006 and 2011, cover the entire coastline of England and Wales.
Each stretch of coastline within an SMP is assigned one of four policy options for each of three time periods (0-20 years, 20-50 years, 50-100 years):
| Policy | Description | When Applied |
|---|---|---|
| Hold the line | Maintain or upgrade existing defences to keep the coastline in its present position | Where significant assets (towns, infrastructure) are at risk |
| Advance the line | Build new defences seaward of the existing coastline | Very rare — expensive and difficult to justify |
| Managed realignment | Allow the coastline to move landward in a controlled way, with management to limit impacts | Where the benefits of retreat outweigh the costs of holding the line |
| No active intervention | No investment in coastal defences; natural processes allowed to operate freely | Where there are few assets at risk, or where defence is not economically justified |
The genuinely sophisticated feature of an SMP is that it assigns a policy for each of three epochs — short term (0–20 years), medium term (20–50 years) and long term (50–100 years) — so a single frontage may be designated, for example, "hold the line" now but "managed realignment" in the final epoch. This temporal sequencing is, in effect, an early form of adaptive management: it commits to defending an asset for as long as it is economically and physically viable, while signalling in advance the intended eventual transition to retreat, allowing communities and investors decades of warning. The approach acknowledges the deep uncertainty of long-term sea-level rise (Lesson 7) by not locking in a single century-long decision. It is, however, only as strong as its implementation: because SMPs are non-statutory, a future council facing local opposition can decline to enact an unpopular long-term realignment policy, and the long warning period can blight property values and erode community trust in the interim — tensions that make SMP delivery as much a social as a technical challenge.
The decision on which policy to apply involves a cost-benefit analysis (CBA), typically conducted by the Environment Agency:
Subscribe to continue reading
Get full access to this lesson and all 10 lessons in this course.