A surge channel is a narrow inlet, usually on a rocky shoreline, and is formed by differential erosion of those rocks by coastal wave action. As waves strike the shore, water fills the channel, and drains out again as the waves retreat. The narrow confines of the channel create powerful currents that reverse themselves rapidly as the water level rises and falls, and cause violent hydrodynamic mixing. However, there is relatively little exchange of water between channels; experimental studies and mathematical modelling of the coastline near Hopkins Marine Station in

California California () is a U.S. state, state in the Western United States that lies on the West Coast of the United States, Pacific Coast. It borders Oregon to the north, Nevada and Arizona to the east, and shares Mexico–United States border, an ...

have shown that water is rapidly mixed within each channel, but that it mostly moves in an oscillatory manner. Surge channels have been likened to 'containment vessels', retaining water borne

gamete A gamete ( ) is a Ploidy#Haploid and monoploid, haploid cell that fuses with another haploid cell during fertilization in organisms that Sexual reproduction, reproduce sexually. Gametes are an organism's reproductive cells, also referred to as s ...

s and probably enhancing the effectiveness of external fertilisation of marine species dwelling within them. Surge channels can form in

reef A reef is a ridge or shoal of rock, coral, or similar relatively stable material lying beneath the surface of a natural body of water. Many reefs result from natural, abiotic component, abiotic (non-living) processes such as deposition (geol ...

s, and the term is sometimes also applied to breaches of coastal

dune A dune is a landform composed of wind- or water-driven sand. It typically takes the form of a mound, ridge, or hill. An area with dunes is called a dune system or a dune complex. A large dune complex is called a dune field, while broad, flat ...

s by storms. Surge channels can range from a few inches across to ten feet or more across. They may create tide pools if the conditions are suitable, but the rapid water movement typically creates a dangerous situation for people or animals that are caught by the current. The West Coast Trail on the coast of

Vancouver Island Vancouver Island is an island in the northeastern Pacific Ocean and part of the Canadian province of British Columbia. The island is in length, in width at its widest point, and in total area, while are of land. The island is the largest ...

is known for its large number of surge channels, some of which are impassable even at low tide and must be crossed inland.

References

{{DEFAULTSORT:Surge Channel Coastal geography Coastal and oceanic landforms

See also

References