Introduction As part of our geography coursework project we had to travel to somerset, Nettlecombe on the 9th July
Deposition of sediment on shore Gullies through the land This sediment then enters the coastal system and is transported by longshore drift. A good example of the sediment budget and longshore drift working together in the coastal system is inlet ebb-tidal shoals, which store sand that has been transported by long-shore transport.
Long shore occurs in a 90 to 80 degree backwash so it would be presented as a right angle with the wave line. Natural features[ edit ] This section consists of features of longshore drift that occur on a coast where long-shore drift occurs uninterrupted by man-made structures.
Spits[ edit ] Provincetown Spit, at the northern end of Cape Codwas formed by longshore drift after the end of the last Ice age.
Spits are formed when longshore drift travels past a point e. Barriers[ edit ] Barrier systems are attached to the land at both the proximal and distal end and are generally widest at the down-drift end.
For example, the Arcachon lagoon is a tidal inlet system in South west France, which provides large sources and sinks for longshore drift sediments.
The impact of longshore drift sediments on this inlet system is highly influenced by the variation in the number of lagoon entrances and the location of these entrances.
Timber groyne from Swanage BayUK Groynes are shore protection structures, placed at equal intervals along the coastline in order to stop coastal erosion and generally cross the intertidal zone.
T-head groynes, which reduce wave height through wave diffraction. Picture showing the use of artificial headlands and detached breakwaters in a coastal system Detached breakwaters[ edit ] Detached breakwaters are shore protection structures, created to build up sandy material in order to accommodate drawdown in storm conditions.
Not only do ports and harbours pose a threat to longshore drift in the short term, they also pose a threat to shoreline evolution.Long shore drift is the movement of sand and sediment along a beach in a particular direction due to the movement of swash (a turbulent layer of water that washes up on the beach after an incoming wave has broken - Wikipedia), backwash carrying the sand in a "saw tooth" motion.
Longshore drift from longshore current is a geological process that consists of the transportation of sediments (clay, silt, sand and shingle) along a coast parallel to the shoreline, which is dependent on oblique incoming wind direction. Oblique incoming wind squeezes water along the coast, and so generates a water current which moves parallel to the coast.
The pile up of water along the shore causes longshore currents that flow parallel to the beach inside the breaker zone. The water in the longshore current returns seaward as rip currents. The spacing between rip currents is usually two to eight times the width of the surf zone.
Long Shore Current. o come.
There are many factors involved with this erosion and they are all a part of what is called coastal geomorphology. Many entire books have been written on the complicated factors involved in co rosion.
This paper will focus mainly on what is known as long shore current and how it is a part of coastal geomorphology. Longshore currents and beach drift Oscillation waves that are breaking at an angle to the shoreline produce translation waves that move diagonally up and down the beach.
This diagonal swash and backwash on the beach creates a longshore current just offshore that moves parallel to the beach and also produces beach drift, which is transport of. This process is called longshore drift and is generated by wave and current action. Water and sediment are transported in a zig-zag pattern as waves and currents approach the shoreline at an angle.
This zig-zag pattern is the mechanism for sediment transport as the swash is immediately followed by the backwash to the ocean.