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 Hopkins Marine Station is the marine laboratory of Stanford University. It is located ninety miles south of the university's main campus, in Pacific Grove, California (United States) on the Monterey Peninsula, adjacent to the Monterey Bay Aquarium. ...

California California is a state in the Western United States, located along the Pacific Coast. With nearly 39.2million residents across a total area of approximately , it is the most populous U.S. state and the 3rd largest by area. It is also the m ...

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 (; , ultimately ) is a haploid cell that fuses with another haploid cell during fertilization in organisms that reproduce sexually. Gametes are an organism's reproductive cells, also referred to as sex cells. In species that produce ...

s and probably enhancing the effectiveness of

external fertilisation External fertilization is a mode of reproduction in which a male organism's sperm fertilizes a female organism's egg outside of the female's body. It is contrasted with internal fertilization, in which sperm are introduced via insemination and then ...

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 processes— deposition of sand, wave erosion planing down rock o ...

s, and the term is sometimes also applied to breaches of coastal dunes by storms. Surge channels can range from a few inches across to ten feet or more across. They may create

tide pools A tide pool or rock pool is a shallow pool of seawater that forms on the rocky intertidal shore. Many of these pools exist as separate bodies of water only at low tide. Many tide pool habitats are home to especially adaptable animals that ...

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 The West Coast Trail, originally called the Dominion Lifesaving Trail, is a backpacking trail following the southwestern edge of Vancouver Island in British Columbia, Canada. It was built in 1907 to facilitate the rescue of shipwrecked survivor ...

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 by ...

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