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A
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Accretion - the accumulation
of (beach) sediment, deposited by natural fluid flow processes
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B
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| Backshore
- the area of shore lying between the average high-tide mark and the
vegetation, affected by waves only during severe storms |
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Barrier island
- elongate coastal islands, generally parallel to the coastline and fronting
the ocean. Barrier islands are rows of parallel ridge of sand created
by repeated deposition and erosion. They generally have beach, dunes,
vegetated terrains and swampy areas. Barrier islands tend to change sharp
and migrate in response to sea level rise and fall and erosion/deposition
process.
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| Beach - aggregation
of unconsolidated sediment, usually sand, that covers the shore |
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| Beach profile
- a profile delineating the shape of the beach surface along a survey line
or transect |
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| Beach ridge
- Large islands that contain a beach, vegetated sand dunes, shrubs,
and a maritime forest. |
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| Benchmark
- A surveyor's mark made on a stationary object of previously determined
position and elevation and used as a reference point in tidal observations
and surveys |
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C
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Continental shelf
- the shallow, near-horizontal sea floor extending from the coast to the
upper continental slope
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Current - a horizontal
movement or flow of water or fluid
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D
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| Deposition
- the laying, placing, or throwing down of any material |
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Dredge (n) - a metal collar
and collecting bag that is dragged along the bottom to sample or collect
rock, sediment, or bottom-dwelling organisms
Dredge (v) - to drag a metal collar and collecting
bay along the bottom to sample or collect rock, sediment, or bottom-dwelling
organisms
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Dune - A hill or ridge of
wind-blown sand deposits
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E
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Ebb tide - the outgoing
or falling tide. It occurs during the transition from high tide to low
tide, when tidal currents move seaward
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| Ebb-tidal
delta - the build up of sediment on the seaward side of inlets formed
by the outgoing tide |
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Elongate - To make
or become longer; stretched out, slender
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Embayment - an indentation
in the shoreline that forms a bay
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Erosion - the chemical
or mechanical movement or disintigration of rock or sediment. In the case
of beaches, it is the physical removal of sediments.
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| Estuary
- A partially enclosed body of water where freshwater is mixed with saltwater |
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F
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Flood tide- the incoming
or rising tide. It occurs during the transition from low to high tide,
when tidal currents move landward
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| Foreshore-
The area of a shoreline that lies between the average high tide mark and
the average low tide mark |
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| Friction
- a force that resists the relative motion or tendency to such motion of
two bodies in contact |
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G
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Glacier - Large mass
of moving ice on land, formed by the recrystallization of snow into ice
under pressure
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Global warming
- an increase in the average temperature of the earth's atmosphere, especially
a sustained increase sufficient to cause climatic change
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Groin- a man-made structure
placed perpendicular to the shoreline that extends from the upper edge
of the beach to below the low tide mark; intended to retard the rate of
erosion
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H
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Headland - a seaward
projection of the coastline, usually composed of durable rock. Headlands
usually protrude outward into the ocean.
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High tide - the tide
at its fullest, when the water reaches its highest level
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Hurricane - a large,
powerful storm having winds that blow > 120 kilometers per hour (75
mph)
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I
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Inlet- a narrow strip of
water cutting between two barrier islands
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Inshore- close to a shore
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Intertidal zone
- the area of the shore that lies between the highest normal high tide
and the lowest normal low tide. Also called the "littoral zone"
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| J |
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Jetty- a man-made structure
placed perpendicular to the shoreline, that extends seaward from the upper
edge of the beach; typically used to stabilize an inlet and to prevent
migration; often placed at the entrance to harbors to slow the natural
longshore drift of sand and subsequent sand build-up in the harbor
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K
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L
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| Lagoon -
a shallow body of water that does not receive significant fresh water inflow
that is seperated from the open ocean by a barrier island |
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| Longshore
current - a current that runs parallel to the shore in the surf zone,
and is powered by breaking waves |
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Longshore drift-
the process by which longshore currents move sediments along the shoreline
along a surf zone
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Low tide- the lowest
level of the tide
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M
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Macrotidal - tides
with a vertical tidal range of greater than four meters
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| Mainland -
the principal landmass of a continent |
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| Maritime
forest- forest constructed near to the sea, though sufficiently distant
from the salt spray |
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| Marsh- a tract
of soft, wet land, usually vegetated by reeds, grasses and occasionally
small shrubs |
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Mesotidal - tides
with a vertical tidal range between two and four meters
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Microtidal - tides
with a vertical tidal range of zero to two meters
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N
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Neap Tide - the maximum
range of tide in an area; it occurs when the moon is in its first and
third quarters
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O
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Offshore zone - open
water that lies seaward of the breaker zone
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P
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| Parallel
- two or more straight coplanar lines that do not intersect |
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| Peat - an organic
deposit consisting predominately of partly decayed plant matter |
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| Perpendicular
- intersecting at or forming right angles |
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| Population
- the collective total of all individuals of a particular species in
an area |
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| Prograding-
a barrier island that is growing seaward or accreting |
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Q
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R
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| Refraction
- the process by which waves are bent and redirected as a consequence
of wave interaction with bottom irregularities |
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| Renourishment-
dredging sand from the bottom of the ocean and then depositing it onto beaches
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| Retrograding-
a barrier island that is moving landward or eroding |
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S
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| Salt marsh
- a vegetated intertidal mud or sand flat, often dominated by species of
Spartina grasses |
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| Sand - grains
of sediment formed by the erosion of rock; one of the components of soil;
often composed of quartz grains |
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| Sand bar-
a coastal depositional feature composed primarily of sand; forms elongate
bottom features; sometimes exposed at low tide |
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Sea - a term applied to the
chaotic motion and irregular form of waves that are generated in the fetch
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| Seafloor
spreading - the process by which basaltic crust is created at the crest
of ocean ridges where lithospheric plates are diverging (moving apart) |
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Seawall- a man-made solid
linear structure constructed parallel to the beach; intended to retard
the rate of erosion and protect beaches or buildings
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| Semi-diurnal
- High tide and low tides occurring twice daily at intervals averaging 12.4
hours |
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| Spit- the elongate
extension of sand on the downdrift end of a barrier island; formed as a
result of longshore drift |
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| Storms -
Storms have a dramatic effect on barrier islands by creating overwash areas
and eroding beaches, as well as other portions of barrier islands. |
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| Storm surge
- Air pressure during severe storms and hurricanes causes the water's
low level to rise. High winds and large waves accentuate this temporary
high sea level, creating a "surge" of water onto the land. |
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| Swash - the
rush of water up the beach face after a wave has broken |
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T
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Transgressive
barrier islands- long, narrow islands that are extremely unstable
because they lack heavy vegetation and healthy dune systems. These deficiencies
make the island susceptible to erosion due to the flooding of ocean waves
over it. These islands are thought to be the erosional end-product of
beach-ridge barrier islands and they migrate landward.
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| Tidal cycle-
the complete cycling from one high tide to the next |
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| Tidal range-
the vertical difference in the height of the water between high and low
tides and determines landward extent of tidal influence |
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Tides- The periodic rise
and fall of the Earth's ocean surface as a consequence of the gravitational
attraction of the Moon and the Sun
Diurnal - High and
low tide occurring once a day
Semi-diurnal -
High tide and low tides occurring twice daily at intervals averaging
12.4 hours
Neap tide - When
tidal range is less than the average; occurring twice a month during
the two quarter phases of the Moon.
Spring tide - At
times of new and full moon when the Sun, Moon, and Earth are directly
in line, the tidal range is greater than average. The gravitational
forces of the Sun and Moon create tidal bulges.
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U
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Uplift- the rising of
the Earth's crust, relative to another part
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V
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W
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| Washover fans-
a fan-shaped accumulation of sand on the landward side of a barrier island
that is deposited when storm waves remove sand from the beach face and deposit
it on the marsh side |
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| Wave - disturbance
that represents energy propagating or moving across the sea's surface. These
deposit and remove sediments from the ocean side of the island. |
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| Wave base -
the level of the water surface equivalent to one-half the wavelength where
wave-induced motion is absent |
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Wave crest - the highest
part of a wave
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Wavelength - the horizontal
distance between corresponding points on successive waves, such as from
crest to crest or trough to trough
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| Wave period
- the time required for two successive crests to pass a fixed point |
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| Wave trough
- the lowest part of a wave |
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| Wind - blow
sediments from the beaches to help form dunes and into the marshes, which
contributes to their build up |
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| Wrackline-
consists of materials that accumulate where the highest swash stops ans
leaves objests stranded; can become the area for new dune formation |
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X
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Y
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Z
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