COASTAL CROSSWORD
Russell Howorth, South Pacific Applied Geoscience Commission, Suva, Fiji
The Coastal Environment is of particular importance in Pacific Islands Nations since on the relatively
small islands that make up the land areas very few places are physically separate from the coast.
Furthermore, the coast is where most of the social and economic development and activities generally
are concentrated.
A knowledge of the physical features and processes of the coastal environment is therefore
important. In order 'to assist you to become more familiar with these physical elements of the
coastal environment attempt the Crossword Puzzle below.
The answers to the crossword puzzle are given in alphabet (or glossary) following the puzzle.
Each word occurs only once, and a few letters are provided in the puzzle to assist you.
ALPHABET (or GLOSSARY) of WORDS
A: ATOLL An atoll is a lowlying island, or group of islands on a coral reef surrounding a
lagoon rarely rising to heights of more than two to three metres above sealevel; made up entirely of
coral reef or reef derived sediment. Many examples occur in the Pacific particularly in Tuvalu, Kiribati
and the Marshall Islands, three countries made up entirely of atoll islands.
B: BEACH The beach commonly represents the boundary between land and ocean. The position,
and shape of a beach often varies from time to time since its position is controlled by a number of
physical processes such as tides, nearshore currents, waves, wind direction, cyclones and supply of
sediment (sand and gravel) from nearby areas.
I
C CYCLONE A cyclone (or typhoon in the northern hemisphere) is an intense area of low pressure
generated over warm ocean waters in low latitudes (often between 5 and 10 degrees north/south of the
equator). They move away from the equator following erratic paths and at speeds often up to 20
kilometres per hour. Associated with cyclones are high winds which can produce high seas and result in
extensive coastal flooding when cyclones are passing slowly close to land with onshore winds. Heavy
rainfall commonly occurs during cyclones which can result in extensive landslides and river flooding on
the higher islands. Winds blow clockwise into a cyclone in the southern hemisphere and anticlockwise
in the northern hemisphere.
D DELTA The broad lowlying coastal area often occurring at the mouth of a large river is a delta.
Several types of delta can be identified from the shape of the coastline produced. Deltas are common
features of the coastline on the larger, higher islands of the region such as Viti Levu in Fiji, and
Guadalcanal in the Solomon Islands.
E EROSION Removal of large volumes of sand from a beach produces erosion. Erosion usually
results from natural physical processes acting over time, but the effects may be accelerated by the
activities of man. With increasing frequency, erosion is resulting in damage to property and loss of land
in densely populated coastal areas.
F FRESHWATER Freshwater is vital to support life, and an important freshwater resource in
coastal areas and particularly atolls is groundwater which can be recovered by use of water wells often
assisted by pumping. On atolls the freshwater occurs as a thin lens "floating" on the seawater due to
the density difference between the two types of water. This resource though renewable when it rains, is
being put under increasing stress as populations increase in coastal communities.
G GEOLOGIST A geologist is a professional technologist or scientist whose aim is to better
understand the history of the Earth and the physical processes taking place within and at the surface
of the planet. A coastal geologist has a particular interest in those surface physical processes
responsible for producing coastlines.
H HALIMEDA Halimeda is a green algae which grows in lagoons. The plant precipitates a thin
layer of calcium carbonate on its leaves, which breaks down to a fine grained carbonate sediment
when the plant dies. This sediment is an important source of sediment on reefs which is not derived
from coral.
I IONS An ion is an electrically charged particle of an atom which occurs in solution. Positive and
negative charged ions (such as positively charged sodium ions and negatively charged chlorine ions)
can combine to produce salts in aqueous solutions. This gives rise to what we are familiar with as the
salty taste of ocean water.
J JETTY A jetty is a man made structure extending out at right angles to the coast usually across a
shallow nearshore area to deeper water to enable easy access to boats. Jetties may be either solid
structures or constructed as a deck on piles. Solid structures may interfere with nearshore currents
flowing along the coast and result in erosion on the down current side of the jetty. An open deck on pile
structure is therefore more acceptable.
K KEY (or Cay) A Key (or cay) is an island of carbonate sand on a reef flat. This may, or may not
be vegetated and in a fixed position. In Pacific Island nations local names exist for example motu in
Kiribati.
L LAGOON Many high islands in the Pacific are fringed by a coral reef. Between the island and the
reef is a lagoon. Many atolls have a coral reef which surrounds, or almost entirely surrounds, a lagoon.
Lagoons are generally areas of sheltered water no more than 20 metres in depth. Shallow lagoons in
areas of high evaporation result in higher salinities of the water.
M MANGROVE Many species of mangroves occur in the region commonly as coastal swamps
fringing the shore. The dense aerial root system of mangrove swamps provide important natural
protection to lowlying areas against wave attack. For a variety of reasons in many areas mangroves
are now being removed, and where no alternative protection has been provided erosion of the coast is
now taking place.
N el NINO EI Nino (otherwise known as Southern Oscillation) is the name given to a regional
change in weather pattern which results in the trade winds ceasing to blow. In turn this changes the
surface water circulation pattern in equatorial areas. As a consequence the region experiences
unusual weather such as droughts, increased cyclone activity, change in the areas where cyclones are
generated: Whilst the cause of EI Nino is still not understood, it is known that this phenomenon occurs
with varying levels of intensity and with a frequency of up to ten years.
o OUTFALL An outfall is the exposed ocean end of a pipeline from which waste, often
sewerage is discharged. Care must be taken to locate outfalls in areas where inshore current
circulation is not going to bring the effluent onshore. This may require careful monitoring of currents
for several months before a decision on the location of an outfall can be made.
P PROTECTION As development takes place, more and more people and property are resident
near the coast. Protection from the natural processes such as erosion and flooding is becoming
increasingly necessary. Care must be take not to increase risk by foolish man made changes. Also
there are many types of protection and it is important that a cost effective solution is chosen. In order
to achieve this an understanding of the coastal physical processes at a given site is important.
Q QUAKE Earthquakes are common in many nations in the region, including Papua New Guinea,
Solomon Islands, Vanuatu, Fiji and Tonga. Uplift and sinking of a coastal and nearby reef
area during an earthquakes is not uncommon. This may result in several meters of relative sealevel
change, permanently flooding some areas and permanently exposing others. Earthquakes can also
produce tsunamis by either disrupting the seafloor or producing submarine landslides.
R RECLAMATION The process of building out the land into the ocean by man is known as
reclamation. Reclaimed land must be protected from wave attack, and care must be taken not to build
on this land until it has compacted. Care must also be taken to ensure that reclaimed areas do not
interfere with nearshore current circulation.
S SAND Sand is an important resource along with gravel that occurs at the coast either on the
beach or in the nearby lagoon/reef areas. Sand and gravel may be derived by natural processes either
from the island or from the reef. Mining of this material from beaches and the lagoon/reef areas is
common. It is important to know how much material is being supplied by natural processes before a
decision can be made about how much can be removed by mining.
T TSUNAMI Tsunamis are commonly known as seismic sea waves since they are often generated
by earthquakes, however they can also result from volcanic activity on islands. As tsunamis approach
land, the water level is raised for a time and coastal flooding of several metres is common. In addition to
tsunamis generated by local earthquakes and volcanic activity, tsunamis generated many thousands of
kilometres away in the north, east and southeast Pacific can travel through the region. Because
tsunamis can travel at speeds of 200-300 kilometres per hour warning of damage from local tsunamis is
not possible.
U UNDERTOW An undertow current also known as a rip current is a dangerous nearshore
current produced when water flowing along the coast returns out to sea by flowing beneath the
incoming surface water back out through a gap in the reef.
V VOLCANO Volcanic activity is one of Mother Nature's most spectacular natural physical
processes. It can also be one of the most destructive. Many active volcanoes occur in Papua New
Guinea, Solomon Islands, Vanuatu, and Tonga. Fiji has hot thermal springs and Western Samoa
historical lava flows on the island of Savaii. During periods of volcanic activity many coastal changes
can take place, for example; ash and pumice erupted may pollute coastal waters for many thousands
of square kilometres. lava may flow to the coast, fill in the lagoon/reef areas and make permanent
changes to the shape of the coast; local tsunamis may be generated.
W WAVES Lower atmosphere winds blowing across the surface water of the oceans, generate a
surface water vertical circulation which results in a swell. As this swell approaches the coast, waves
are produced by the effect of the shallowing seafloor on the vertical circulation.
X XRA Y Xray laboratory technology, just like that which is used to see inside our bodies, is being
increasingly used to study the growth patterns of corals on the reef. Differences in growth patterns may
be related to extreme climatic events or to increase in man made pollution.
Y YEARLY The coast is in dynamic equilibrium in response to a number of physical processes.
Over time the rates at which each of these processes act varies, so too does the rate at which each
process acts. Site specific studies of these processes over yearly periods allows for
a better understanding of the factors which contribute to the stability of a particular stretch of
coastline.
Z ZONE Many factors which contribute to the shape and stability of coasts in Pacific Island Nations
do not simply act at the coastline, nor are the effects of changes taking place restricted to the coastline
itself. For practical management purposes it is wise to consider the coast as a zone extending from
several tens (if not hundreds) of metres onshore from the actual coastline, out to beyond the reef. In
many islands in effect the whole island can be regarded as part of the coastal zone.