Geography Flashcards
What is Abrasion?
Abrasion - rocks carried along by the river wear down the river bed and banks.
Hydraulic Action
Hydraulic action - the force of the river against the banks can cause air to be trapped in cracks and crevices. The pressure weakens the banks and gradually wears it away.
What is Attrition
Attrition - rocks being carried by the river smash together and break into smaller, smoother and rounder particles.
What is Solution?
Solution - soluble particles are dissolved into the river.
What are groynes
A groyne is an active structure extending from shore into sea, most often perpendicularly or slightly obliquely to the shoreline.
What is hard engineering?
Hard engineering options tend to be expensive, short-term options. They may also have a high impact on the landscape or environment and be unsustainable.
What is soft engineering?
Soft engineering options are often less expensive than hard engineering options. They are usually more long-term and sustainable, with less impact on the environment.
What is Beach Management?
Beach management
This replaces beach or cliff material that has been removed by erosion or longshore drift.
The main advantage is that beaches are a natural defence against erosion and coastal flooding. Beaches also attract tourists.
It is a relatively inexpensive option but requires constant maintenance to replace the beach material as it is washed away.
What is managed retreat
Managed retreat
Areas of the coast are allowed to erode and flood naturally. Usually this will be areas considered to be of low value - eg places not being used for housing or farmland.
The advantages are that it encourages the development of beaches (a natural defence) and salt marshes (important for the environment) and cost is low.
Managed retreat is a cheap option, but people will need to be compensated for loss of buildings and farmland.
What is coastal flooding?
Coastal flooding occurs when normally dry, low-lying land is flooded by seawater. The extent of coastal flooding is a function of the elevation inland flood waters penetrate which is controlled by the top of the coastal land exposed to flooding.
Risks of coastal flooding
Homes, businesses and cars belonging to more than 1,000 people were swept away.
Income from tourism was lost. This had an impact on livelihoods and the local economy.
There were vast numbers of subsequent insurance claims.
No lives were lost, partly due to the rapid response of the emergency services.
Causes of coastal flooding
Over 60 mm of rainfall (typically a month’s rainfall) fell in two hours.
The ground was already saturated due to the previous two weeks of above average rainfall.
The drainage basin has many steep slopes, and has areas of impermeable slate causing rapid surface run-off.
What is a drainage basin?
A drainage basin or ‘catchment area’ is any area of land where precipitation collects and drains off into a common outlet, such as into a river, bay, or other body of water.
What is a soil creep?
Downhill creep, also known as soil creep or commonly just creep, is the slow downward progression of rock and soil down a low grade slope; it can also refer to slow deformation of such materials as a result of prolonged pressure and stress.
What is mass movement?
Mass movement is the movement of surface material caused by gravity. Landslides and rockfalls are examples of very sudden movements of this type. Of course geological agents such as water, wind and ice all work with gravity to cause a leveling of land.
