name all 6 defences
sea wall, gabions, rock wall, groynes, beach nourishment and reprofiling, dune regeneration
what is a sea wall?
a wall made of hard material like concrete that reflects the waves back to sea
what is gabions?
a wall of wired cages filled with rocks, usually built at the foot of cliffs.
what is rock armour?
boulders that are pilled up along the coast.
what are groynes?
wooden stone fences that are built at right angles to the coast. They trap material transported by longshore drift
what is beach nourishment?
sand and shingle from elsewhere added to the upper part of beaches
what is dune regeneration?
creating or restoring sand dunes by nourishment, or by planting vegetation to stabilise the land.
what are the benefits of sea walls?
it prevents erosion of the coast and acts as a barrier to prevent flooding
what are the benefits of gabions?
absorb wave energy and reduce erosion. cheap and easy to build.
benefits of rock armour?
it absorbs wave energy, reduces erosion and flooding. pretty cheap.
benefits of groynes?
crates wider beaches which slows the waves. protection against flooding and erosion.
benefits of beach nourishment and reprofiling?
creates wider beaches so the waves are slower. protection against flooding and erosion.
benefits of dune regeneration?
dunes create a barrier between land and sea and absorb wave energy, preventing flooding and erosion. stabilisation and cheap.
costs of sea wall?
expensive, creates a strong backlash that erodes under the wall
costs of gabions?
ugly and corrode over time
costs of rock armour?
boulders can be moved around strong waves and need to be replaced
costs of groynes?
they starve beaches further down the cost, making them narrower. this leads to greater erosion
costs of beach nourishment and reprofiling?
kills organisms, very expensive , must be repeated
costs of dune regeneration?
protection to a small area. nourishment is very expensive
What is Traction in the context of riverbed processes?
Large, heavy particles such as boulders are rolled or pushed along the river bed by the force of the flowing water
This process involves the movement of larger sediment due to the energy of the water.
Define Saltation in riverbed sediment transport.
Medium-sized particles, like pebbles, bounce along the river bed, being lifted briefly by the water’s force before falling back down
Saltation is characterized by the intermittent lifting and dropping of particles.
What does Suspension refer to in river transport?
Fine particles, including silt and clay, are carried within the water itself
This process allows smaller particles to remain afloat and travel with the water flow.
What is meant by Solution in the context of river transport?
Dissolved materials, such as certain minerals or salts, are carried invisibly within the water as they have fully dissolved
This process involves the transport of substances that are not visible to the naked eye.
