coastal management Flashcards
what is longshore drift
movement of sediment in a zigzag manner parallel to the shore
4 approaches to coastal management
hold the line, advance the line, retreat the line, do nothing
hard engineering schemes
groynes, seawalls, breakwaters, gabions, rip-rap, revetments
how do groynes work
concrete or wooden walls that extend from the coastline and act as a sand trap to halt longshore drift, causing sand to pile up on the side facing the direction of longshore drift
prevents beaches from being eroded away which is useful for areas like tourist resorts, however they also stop sand from reaching areas further down the coast, causing more serious erosion there
how do seawalls work
walls aim to reflect the force of waves which protects coasts from erosion
how to breakwaters work
parallel to the shore and reduce the wave energy reaching the protected area, can be attached or detached to the shoreline
how do gabions work
small rocks held in wire cages to reduce the impact of waves on a cliff
how does rip-rap work
large rocks at the foot of seawalls or cliffs that absorb waves
soft engineering schemes
beach nourishment
decision making strategies
cost-benefit analysis, environmental impact assessment, feasibility studies, risk assessment, shoreline management plan
how does beach nourishment work
carried out in areas where sand is eroded or beach is important recreational resource, sand and shingle is brought to an eroded beach to replace the eroded materials which helps to dissipate the strength of the waves
what is cost benefit analysis
considers the social and economic aspects of a coastal management strategy and weighs the benefits of a scheme with the costs of building and maintaining it
what is environmental impact assessment
assesses the effects any strategy will have on an area and its environment, especially along coastlines where attractive scenery and ecosystems are tourist assets
what are feasibility studies
technical merits of a scheme and site, whether engineering is planned to suit local geology or coastal processes
what is risk assessment
taking decisions in light of likely recurrence interval and what is at risk, legal claims and insurance make it an important future consideration
