Coastal and river management strategies

OCR J383 regularly asks 8-mark "evaluate" questions about management strategies. You must know the difference between hard and soft engineering AND be able to evaluate the advantages and disadvantages of each approach.

River flood management

Hard engineering

Method	How it works	Advantage	Disadvantage
Dam and reservoir	Traps water upstream; releases it slowly	Controls flow; water supply; HEP	Expensive; displaces communities; traps sediment
Channelisation	Straightens/deepens river; lined with concrete	Increases speed; reduces local flooding	Speeds water downstream; flooding worsened elsewhere
Embankments/levées	Raised banks either side of river	Cheap; keeps floodwater out	Can be breached; creates false sense of security
Flood relief channel	Artificial bypass channel	Diverts excess water	Expensive; requires land

Soft engineering

Method	How it works	Advantage	Disadvantage
Flood warnings	Monitoring and alerts	Cheap; saves lives without structural change	Does not prevent flooding
Floodplain zoning	Restricts building types near river	Reduces damage; affordable	Controversial; limits development
Afforestation	Planting trees in the catchment	Intercepts rain; reduces runoff	Slow to establish; needs large areas
Managed retreat	Allowing the river to flood naturally	Restores habitat; cheap	Loss of agricultural land

Coastal management

Hard engineering

Method	How it works	Advantage	Disadvantage
Sea wall	Concrete wall reflects wave energy	Strong protection for towns	Expensive; reflects energy → scours beach; ugly
Groynes	Wooden/rock barriers at right angles to coast	Trap sediment; build up beach; cheap	Starve beaches downshore of sediment
Rock armour (rip-rap)	Large boulders at cliff base	Cheap; absorbs wave energy	Ugly; can be moved by storms
Offshore reef/breakwater	Submerged barrier breaks wave energy	Protects coastline naturally	Expensive; navigation hazard

Soft engineering

Method	How it works	Advantage	Disadvantage
Beach nourishment	Sand pumped/shipped from elsewhere	Natural-looking; maintains beach for tourism	Expensive; needs repeating; temporary
Cliff stabilisation	Drainage, planting, rock bolts	Reduces mass movement	Expensive; limited effect on severe erosion
Managed retreat (coastal realignment)	Allow coastline to retreat; compensate landowners	Cheap; creates habitat; sustainable	Controversial; political opposition
Do nothing	No intervention	Cheapest option	Land/property lost

Evaluation framework

When evaluating strategies:

• Effectiveness: does it actually prevent flooding/erosion?
• Cost: who pays? Is it affordable?
• Environmental impact: what happens to the ecosystem?
• Sustainability: how long will it last? Does it cause problems elsewhere?
• Social impact: who benefits? Who loses out?

Case study — Holderness Coast (coastal erosion management)

The Holderness Coast (East Yorkshire) erodes at an average rate of 1–2 metres per year — one of the fastest in Europe:

• Rock armour at Mappleton village protects the village.
• But the rock armour interrupts longshore drift → beaches further south (Cowden/Happisburgh) are starved of sediment → faster erosion there.
• The 2005 shoreline management plan for Holderness includes "managed retreat" for much of the coast but hard engineering at settlements.

Common OCR exam mistakes

1. Saying hard engineering is always "better" — examiners want a balanced evaluation.
2. Forgetting to use an example: "some places use sea walls" scores less than "Mappleton uses rock armour."
3. Not explaining the knock-on effects of management — groynes starve beaches downshore; channelisation speeds flooding downstream.