Podcast
Questions and Answers
➢ It is the branch of surveying which deals with
waterbodies e.g. Lake, river etc.
➢ Is the process employed in gathering
information concerning any body of water
and its adjacent land areas.
➢ It is the branch of surveying which deals with waterbodies e.g. Lake, river etc. ➢ Is the process employed in gathering information concerning any body of water and its adjacent land areas.
The usual fundamental principles of
surveying and leveling are adopted for
acquiring data for determination of :
The usual fundamental principles of surveying and leveling are adopted for acquiring data for determination of :
Purpose of hydro
Purpose of hydro
➢ the study, description, and mapping of
oceans, seas, lakes, and rivers especially with
reference to their navigational and
commercial or other uses
➢ the study, description, and mapping of oceans, seas, lakes, and rivers especially with reference to their navigational and commercial or other uses
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➢ the process of measuring the depth of a body
of water at a particular point.
➢ the process of measuring the depth of a body of water at a particular point.
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➢ the process of making measurements in
streams and rivers for the purpose of
predicting the rate of discharge at various
water levels or stages.
➢ the process of making measurements in streams and rivers for the purpose of predicting the rate of discharge at various water levels or stages.
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➢ a unit used for the measurement of water
depth and is equivalent to six (6) feet
➢ a unit used for the measurement of water depth and is equivalent to six (6) feet
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➢ a map or chart used in navigation. It is
basically similar to topographic map except
that water depths, navigational markers, and
the character of underwater surface are
indicated.
➢ a map or chart used in navigation. It is basically similar to topographic map except that water depths, navigational markers, and the character of underwater surface are indicated.
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➢ are specific tide levels which are used as
surfaces of reference for depth
measurements in the sea and as a base for
the determination of elevation on land
➢ are specific tide levels which are used as surfaces of reference for depth measurements in the sea and as a base for the determination of elevation on land
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➢ the volume of water flowing past a section of
a stream, canal, flume, and other waterways.
It is usually expressed in cubic feet per
second or cubic meters per second.
➢ the volume of water flowing past a section of a stream, canal, flume, and other waterways. It is usually expressed in cubic feet per second or cubic meters per second.
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➢ a current or steady flow of water running
along the earth’s surface.
➢ a current or steady flow of water running along the earth’s surface.
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➢ the process of scooping or sucking up mud,
sand, rocks and other materials underwater
for the purpose of enlarging, deepening or
clearing channels, harbors, rivers, and other
bodies of water.
➢ the process of scooping or sucking up mud, sand, rocks and other materials underwater for the purpose of enlarging, deepening or clearing channels, harbors, rivers, and other bodies of water.
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➢ an imaginary line on the surface of the earth
found underwater, all points of which are of
the same elevation. They are sometimes
known as depth curves or bathymetric
contour
➢ an imaginary line on the surface of the earth found underwater, all points of which are of the same elevation. They are sometimes known as depth curves or bathymetric contour
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hydrographic survey
hydrographic survey
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➢ various types are used for hydrographic
surveys. These includes rowboats, motor
launches, and small vessels.
➢ various types are used for hydrographic surveys. These includes rowboats, motor launches, and small vessels.
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➢ a graduated and rounded piece
of lumber, about 3 meters long, used for taking
soundings. It is suitable for use where the water
depth does not exceed 2 ½ meters.
➢ a graduated and rounded piece of lumber, about 3 meters long, used for taking soundings. It is suitable for use where the water depth does not exceed 2 ½ meters.
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➢ a leadline or sounding line is usually a length
of sash or hemp cord, braided flax, or nylon
cord, with sounding lead attached to one end
➢ a leadline or sounding line is usually a length of sash or hemp cord, braided flax, or nylon cord, with sounding lead attached to one end
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➢ a simple device in which piano or stranded
wire is used and wound on areel mounted on
a stand
➢ a simple device in which piano or stranded wire is used and wound on areel mounted on a stand
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➢ a measuring device which automatically
records soundings taken on a moving vessel
➢ a measuring device which automatically records soundings taken on a moving vessel
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➢ signal are constructed In a variety of ways
but they should be seen and easily
distinguished from each other
➢ signal are constructed In a variety of ways but they should be seen and easily distinguished from each other
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➢ are instruments for measuring the height of
the tide (non-recording gages & automatic or
self registering gages)
➢ are instruments for measuring the height of the tide (non-recording gages & automatic or self registering gages)
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➢ a portable device and hand-held instrument
used for measuring horizontal and vertical
angels
➢ a portable device and hand-held instrument used for measuring horizontal and vertical angels
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the half-daily cycle of rhythmic rise and fall of
the surface of oceans, seas, lakes, bays, rivers,
and other bodies of water connected with
them due to the gravitational attraction of
the sun and moon acting upon the rotating
earth
the half-daily cycle of rhythmic rise and fall of the surface of oceans, seas, lakes, bays, rivers, and other bodies of water connected with them due to the gravitational attraction of the sun and moon acting upon the rotating earth
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➢ the horizontal movement of water
accompanying tides and which is produced
by the combined action of astronomical,
hydrological, and meteorological factors
➢ the horizontal movement of water accompanying tides and which is produced by the combined action of astronomical, hydrological, and meteorological factors
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➢ the period within which the water surface is
rising and moving toward the shore
➢ the period within which the water surface is rising and moving toward the shore
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➢ the period within which the water surface is
falling and moving seaward
➢ the period within which the water surface is falling and moving seaward
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➢ the instant at which the tidal current is
changing direction and flows neither in or
out.
➢ the instant at which the tidal current is changing direction and flows neither in or out.
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➢ refers to the direction of current flow
➢ refers to the direction of current flow
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➢ refers to the speed of current flow
➢ refers to the speed of current flow
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➢ refers to the maximum height to which the
water surface rises above the standard
datum plane during a given period. It is also
known as “HIGH TIDE”.
➢ refers to the maximum height to which the water surface rises above the standard datum plane during a given period. It is also known as “HIGH TIDE”.
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➢ or “LOW TIDE” refers to the greatest
depression of the water surface below the
standard datum plane during a given period.
Tide Range – the difference between the high
and low tide at a certain location on a given
date.
➢ or “LOW TIDE” refers to the greatest depression of the water surface below the standard datum plane during a given period. Tide Range – the difference between the high and low tide at a certain location on a given date.
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➢ consist of an idealized average period of 24
hours and 50 minutes between the
occurrence of two successive high tides of the
same type at the same location.
➢ consist of an idealized average period of 24 hours and 50 minutes between the occurrence of two successive high tides of the same type at the same location.
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➢ is the period around which the greatest peak
or depression of the tides is reached and
during which any change in height of the tide
is scarcely noticeable.
➢ is the period around which the greatest peak or depression of the tides is reached and during which any change in height of the tide is scarcely noticeable.
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➢ consist of a large head or front of water
generated at the surface of the ocean by force
winds of hurricanes or typhoons, or by
isostatic adjustment of the ocean floor
accompanying a submarine earthquake
➢ consist of a large head or front of water generated at the surface of the ocean by force winds of hurricanes or typhoons, or by isostatic adjustment of the ocean floor accompanying a submarine earthquake
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➢ Are specific tide levels which are used as
surfaces of reference for depth
measurements in the sea and as a base for
the determination of elevation on land. The
height of these surfaces will depend on local
conditions and therefore it cannot be
transferred from some other locality by
levels or computed from geodetic mean sea
level
➢ Are specific tide levels which are used as surfaces of reference for depth measurements in the sea and as a base for the determination of elevation on land. The height of these surfaces will depend on local conditions and therefore it cannot be transferred from some other locality by levels or computed from geodetic mean sea level
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Principal Tidal datums
Principal Tidal datums
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➢ are those characterized by two high and two
low waters each tidal day.
➢ are those characterized by two high and two low waters each tidal day.
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➢ are those which, in the long run, display but
one high and low water each day.
➢ are those which, in the long run, display but one high and low water each day.
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➢ a type of tide which has two high waters and
has two low water each day.
➢ a type of tide which has two high waters and has two low water each day.
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➢ These are used to determine the exact water
surface level
➢ The movement of tides during the time
soundings are made.
➢ The gauges are read at regular intervals,
varying from 10m to 30 min
➢ These are used to determine the exact water surface level ➢ The movement of tides during the time soundings are made. ➢ The gauges are read at regular intervals, varying from 10m to 30 min
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➢ Simplest type of gauge.
➢ It consists of a graduated board, 150 to 250
mm wide and 100 mm thick, fixed in vertical
position
➢ Simplest type of gauge. ➢ It consists of a graduated board, 150 to 250 mm wide and 100 mm thick, fixed in vertical position
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➢ The float gauge is designed to overcome the
difficulty in reading a staff gauge when the
intensity of tides is high and the variations of
water level is more.
➢ It consists of a float to which a graduated
vertical staff is attached.
➢ The float gauge is designed to overcome the difficulty in reading a staff gauge when the intensity of tides is high and the variations of water level is more. ➢ It consists of a float to which a graduated vertical staff is attached.
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➢ The weight gauge consists a weight attached
to brass chain or wire.
➢ The chain passes over a pulley, and is laid
horizontal along the side of a graduated scale.
➢ The weight is lowered to touch the water
surface, and the reading is taken on the
graduated scale against an index attached to
the chain.
➢ The weight gauge consists a weight attached to brass chain or wire. ➢ The chain passes over a pulley, and is laid horizontal along the side of a graduated scale. ➢ The weight is lowered to touch the water surface, and the reading is taken on the graduated scale against an index attached to the chain.
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➢ Self registering tide gauges automatically
record the variation of water level with time
➢ Self registering tide gauges automatically record the variation of water level with time
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➢ When locating sounding for a hydrographic
survey, the composition of the boat party will
depend upon the survey method used.
Usually the following personnel will form the
boat party
➢ When locating sounding for a hydrographic survey, the composition of the boat party will depend upon the survey method used. Usually the following personnel will form the boat party
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➢ Person who directs all survey operation of
the party, he is responsible for the accurate
gathering of the required survey data which
will be needed in the preparation and
compilation of the hydrographic chart.
➢ Person who directs all survey operation of the party, he is responsible for the accurate gathering of the required survey data which will be needed in the preparation and compilation of the hydrographic chart.
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➢ Person who is responsible for setting up the
different instruments to be used in
hydrographic survey
➢ Person who is responsible for setting up the different instruments to be used in hydrographic survey
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➢ Person whose task us to record all the survey
data gathered
➢ Person whose task us to record all the survey data gathered
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➢ Handles the leadline or the sounding rod, he
also serves as a lookout
➢ Handles the leadline or the sounding rod, he also serves as a lookout
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➢ Responsible for steering the boat on selected
compass bearing or range
➢ Responsible for steering the boat on selected compass bearing or range
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➢ In waters where there are expected dangers
to navigation a lookout is employed. He is
stationed at the most suitable elevated
position in the boat. He should report all
possible hazards so that proper action can be
taken.
➢ In waters where there are expected dangers to navigation a lookout is employed. He is stationed at the most suitable elevated position in the boat. He should report all possible hazards so that proper action can be taken.
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➢ Person who alerts the shore party that
sounding is about to begin. He is equipped
with a set of colored flag
➢ Person who alerts the shore party that sounding is about to begin. He is equipped with a set of colored flag
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➢ In deep water surveys where a fathometer is
employed, the attendant focus full attention
on this instrument.
➢ In deep water surveys where a fathometer is employed, the attendant focus full attention on this instrument.
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➢ Are well-defined lines on courses whose
position are known and along which
sounding are taken.
➢ Are well-defined lines on courses whose position are known and along which sounding are taken.
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➢ Buoy is a floating object anchored in place in
a body of water by a heavy weight to which
buoy is attached by a rope or chain
➢ Buoy is a floating object anchored in place in a body of water by a heavy weight to which buoy is attached by a rope or chain
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➢ Is generally used when the required accuracy
of the survey is not high. This Method is
simple and economical to undertake.
➢ Is generally used when the required accuracy of the survey is not high. This Method is simple and economical to undertake.
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➢ Is Commonly used on small lakes or range
lines extend only to relatively short distances
towards the water from the shore area
➢ Is Commonly used on small lakes or range lines extend only to relatively short distances towards the water from the shore area
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➢ The fixed range lines are located on shore
and so laid out to intersect at approximately
right angles. Signals are used to mark each
range line. The boar proceeds to the
intersection of any two range lines and
sounding are taken.
➢ The fixed range lines are located on shore and so laid out to intersect at approximately right angles. Signals are used to mark each range line. The boar proceeds to the intersection of any two range lines and sounding are taken.
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➢ Is performed in a manner similar to that of
stadia surveying. It is convenient for surveys
of small bodies of water.
➢ Is performed in a manner similar to that of stadia surveying. It is convenient for surveys of small bodies of water.
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➢ A common method of locating sounding is to
direction to the boat simultaneously from to
instrument station. This method is adapted
when it is difficult to establish range signals
on shore
➢ A common method of locating sounding is to direction to the boat simultaneously from to instrument station. This method is adapted when it is difficult to establish range signals on shore
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➢ In order that the position of the boat used in
sounding could be located and plotted on a
map, to angles need to be simultaneously
observed from the boat to three fixed points
on shore. This method of locating sounding is
an application of the three point problem
➢ In order that the position of the boat used in sounding could be located and plotted on a map, to angles need to be simultaneously observed from the boat to three fixed points on shore. This method of locating sounding is an application of the three point problem
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➢ Locating sounding by stretching a graduated
wire or cross rope across a narrow stream is
a method suitable for surveying detailed
cross- section of rivers and channels. The
procedure, which is sometimes called the
"Tag-line" method, is very accurate but more
expensive to undertake as compared to
locating sounding along range lines
➢ Locating sounding by stretching a graduated wire or cross rope across a narrow stream is a method suitable for surveying detailed cross- section of rivers and channels. The procedure, which is sometimes called the "Tag-line" method, is very accurate but more expensive to undertake as compared to locating sounding along range lines
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➢ A convenient method of locating sounding
where there is a cliff or high bluff is by
observing vertical (depression) angles with a
transit or a theodolite.
➢ This method, which is also known as the
"Norwegian Method" is particularly useful
when the instrument used can be set up at
stations having a commanding view of the
lake
➢ A convenient method of locating sounding where there is a cliff or high bluff is by observing vertical (depression) angles with a transit or a theodolite. ➢ This method, which is also known as the "Norwegian Method" is particularly useful when the instrument used can be set up at stations having a commanding view of the lake
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∝
∝
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DE
DE
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HI
HI
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HD
HD
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➢ Designed to measure the time of transit or
difference in transit times of electromagnetic
waves in the atmosphere.
➢ A typical system consists essentially of
transmitting on a fixed frequency, an
unmodulated radio wave from the ship to the
three triangulation stations of known
position.
➢ Requires a relay unit on shore which must be
equipped with a transmitter, receiver and an
amplifier
➢ Designed to measure the time of transit or difference in transit times of electromagnetic waves in the atmosphere. ➢ A typical system consists essentially of transmitting on a fixed frequency, an unmodulated radio wave from the ship to the three triangulation stations of known position. ➢ Requires a relay unit on shore which must be equipped with a transmitter, receiver and an amplifier
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➢ Originally developed for blind bombing by
military aircraft and aerial photographic
reconnaissance.
➢ Usually employed when a rapid
determination of position is required even
under adverse weather conditions.
➢ Widely used now often in most offshore
measurements and in establishing
triangulation stations for horizontal control
networks.
➢ range of from about 80 to 120 kilometers
depending largely on the height of antennas
used
➢ Originally developed for blind bombing by military aircraft and aerial photographic reconnaissance. ➢ Usually employed when a rapid determination of position is required even under adverse weather conditions. ➢ Widely used now often in most offshore measurements and in establishing triangulation stations for horizontal control networks. ➢ range of from about 80 to 120 kilometers depending largely on the height of antennas used
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➢ Principle employed is similar to Shoran
except for the use and transmission of high
pules of electromagnetic energy.
➢ High frequency waves are employed in the
Loran method since these waves allow the
measurement of greater distances.
➢ Principle employed is similar to Shoran except for the use and transmission of high pules of electromagnetic energy. ➢ High frequency waves are employed in the Loran method since these waves allow the measurement of greater distances.
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➢ Combines some of the principles and
techniques used in long-range and shortrange navigation.
➢ US Coast and Geodetic Surveys developed
this system in order to increase the
measuring capability of the two systems
developed earlier while still maintaining a
comparable degree of accuracy.
➢ Combines some of the principles and techniques used in long-range and shortrange navigation. ➢ US Coast and Geodetic Surveys developed this system in order to increase the measuring capability of the two systems developed earlier while still maintaining a comparable degree of accuracy.
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➢ Another method of control used in
hydrographic surveying used to determine
the position of a survey vessel.
➢ It's functional during night
➢ Another method of control used in hydrographic surveying used to determine the position of a survey vessel. ➢ It's functional during night
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➢ Method of measuring the depth of water by
determining the time required for sound
waves to travel from a point near the surface
of the water to the bottom and back.
➢ Method of measuring the depth of water by determining the time required for sound waves to travel from a point near the surface of the water to the bottom and back.
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➢ Mounted on a small boat or suspended over
the side.
➢ Operated by dry batteries and can be easily
shifted from one boat to another.
➢ Read by means of a meter or a scale since
they do not have the capability to move and
mark a paper strip.
➢ Mounted on a small boat or suspended over the side. ➢ Operated by dry batteries and can be easily shifted from one boat to another. ➢ Read by means of a meter or a scale since they do not have the capability to move and mark a paper strip.
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➢ Considered part of the navigation equipment
of the sounding vessel or survey
➢ Designed to measure sounding to depths of
over 60 meters to an accuracy of about ½
centimeter.
➢ These fathometers are very sensitive and
have the capability to record reflections from
layers of different density.
➢ Depths up to about 60 meters can be
determined by use of portable fathometers
➢ Considered part of the navigation equipment of the sounding vessel or survey ➢ Designed to measure sounding to depths of over 60 meters to an accuracy of about ½ centimeter. ➢ These fathometers are very sensitive and have the capability to record reflections from layers of different density. ➢ Depths up to about 60 meters can be determined by use of portable fathometers
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ADVANTAGES AND LIMITTATIONS OF ECHO
SOUNDERS
ADVANTAGES AND LIMITTATIONS OF ECHO SOUNDERS
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CONDITIONS INFLUENCING ECHO SOUNDINGS
CONDITIONS INFLUENCING ECHO SOUNDINGS
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➢ Recently copied by echo sounders to provide
an intermediate printout of sounding depths
and their related positions.
➢ Recently copied by echo sounders to provide an intermediate printout of sounding depths and their related positions.
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➢ Developed to allow interpolation between
plotted depths and plotters are utilized to
draw the depth (bathymetric) contours
automatically just as in automated plotting
for topographic surveys.
➢ Developed to allow interpolation between plotted depths and plotters are utilized to draw the depth (bathymetric) contours automatically just as in automated plotting for topographic surveys.
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➢ Employs lasers, offers high accuracies but is
applicable only to depths less than 50m,
➢ Employs lasers, offers high accuracies but is applicable only to depths less than 50m,
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➢ Soon expected to replace conventional
hydrographic survey methods performed on
board sounding vessels.
➢ Soon expected to replace conventional hydrographic survey methods performed on board sounding vessels.
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➢ An air bome lasers system. a pulse type laser
is used to emit a burst of light which is
reflected at the water surface and at the
bottom of the body of water.
➢ An air bome lasers system. a pulse type laser is used to emit a burst of light which is reflected at the water surface and at the bottom of the body of water.
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➢ Allow remote measurements of water depths.
•Systems are based on the principle that less
energy is returned from deep waters than
from shallow waters, calibration of such a
system is done by comparing returned
energy with known water depths.
➢ Allow remote measurements of water depths. •Systems are based on the principle that less energy is returned from deep waters than from shallow waters, calibration of such a system is done by comparing returned energy with known water depths.
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➢ Another type of airborne hydrographic
system being developed, in this method, an
aerial camera is used to photograph the
water areas using standard techniques of
photogrammetry. Natural color film is used
in photography.
➢ Has been found to be accurate in locating
depths up to 20m in clear water.
➢ Another type of airborne hydrographic system being developed, in this method, an aerial camera is used to photograph the water areas using standard techniques of photogrammetry. Natural color film is used in photography. ➢ Has been found to be accurate in locating depths up to 20m in clear water.
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➢ The interpretation of multispectral imagery
is primarily based on the tones of the objects
viewed. Depending upon the spectral
reflectance of the object, tone varies with the
wavelength. Any surface that reflects
strongly in a certain band of the spectrum is
said to have a high response in that band.
➢ The interpretation of multispectral imagery is primarily based on the tones of the objects viewed. Depending upon the spectral reflectance of the object, tone varies with the wavelength. Any surface that reflects strongly in a certain band of the spectrum is said to have a high response in that band.
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Launched by the United States of America in
July 23, 1972 into a sun-synchronous orbit
around the Earth at an altitude of 919kms.
Launched by the United States of America in July 23, 1972 into a sun-synchronous orbit around the Earth at an altitude of 919kms.
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Butterfly-shaped observatory weighing _______ which circled the Earth the Earth every ______________
Butterfly-shaped observatory weighing _______ which circled the Earth the Earth every ______________
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FIRST LANDSAT SATELLITE
FIRST LANDSAT SATELLITE
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- unit used in remote
sensing to express the wavelength of an
electromagnetic spectrum.
- unit used in remote sensing to express the wavelength of an electromagnetic spectrum.
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➢ Wavelengths range from 500-600nm.
➢ Water is quite transparent in this band and it
tends to enhance features such as sediment
with water.
➢ Wavelengths range from 500-600nm. ➢ Water is quite transparent in this band and it tends to enhance features such as sediment with water.
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Four bands of the spectrum
Four bands of the spectrum
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➢ Wavelengths ranges from 600-700nm.
➢ Show good contrast between natural surface
cover and man-made structures.
➢ Artificial structures appear very bright
against the dark appearance of vegetation
➢ Wavelengths ranges from 600-700nm. ➢ Show good contrast between natural surface cover and man-made structures. ➢ Artificial structures appear very bright against the dark appearance of vegetation
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➢ method of taking leadline sounding at cettain
interval will usually give a satinfuctorul
representation of the shape of the bottom of
a body of water which is uniporm and
without abrupt changes
➢ method of taking leadline sounding at cettain interval will usually give a satinfuctorul representation of the shape of the bottom of a body of water which is uniporm and without abrupt changes
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➢ this device congist of a horizontal bottom
wire of suitable length which may be set at
any deaited depth it in used to locate under
water water obstraction. The" wire 19
supported at regular intervals by adjustable
upright cables which are suspended from
qurface buoys.
➢ this device congist of a horizontal bottom wire of suitable length which may be set at any deaited depth it in used to locate under water water obstraction. The" wire 19 supported at regular intervals by adjustable upright cables which are suspended from qurface buoys.
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➢ The length of the vertical cables supporting
the bottom wite cannot be adjusted, and
these cables are positioned much farther
apart. Alau imo intermediate ploata are
Faatened to the write such as that there are
no provision for representing the sag of the
wire between cables.
➢ The length of the vertical cables supporting the bottom wite cannot be adjusted, and these cables are positioned much farther apart. Alau imo intermediate ploata are Faatened to the write such as that there are no provision for representing the sag of the wire between cables.
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➢ is to determine minimum clear depths. They
locate obstruction and navigation danger in
confine areas such ag shwals. rock pinnades,
refers, or wreck. The sweep bar is a heavy
section. of tail road, steel pipe, or a atructural
ateel section. it is held by two vertical calde.
➢ is to determine minimum clear depths. They locate obstruction and navigation danger in confine areas such ag shwals. rock pinnades, refers, or wreck. The sweep bar is a heavy section. of tail road, steel pipe, or a atructural ateel section. it is held by two vertical calde.
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➢ this device congist of a horizontal bottom
wire of suitable length which may be set at
any deaited depth it in used to locate under
water water obstraction. The" wire 19
supported at regular intervals by adjustable
upright cables which are suspended from
qurface buoys.
➢ this device congist of a horizontal bottom wire of suitable length which may be set at any deaited depth it in used to locate under water water obstraction. The" wire 19 supported at regular intervals by adjustable upright cables which are suspended from qurface buoys.
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➢ The length of the vertical cables supporting
the bottom wite cannot be adjusted, and
these cables are positioned much farther
apart. Alau imo intermediate ploata are
Faatened to the write such as that there are
no provision for representing the sag of the
wire between cables.
➢ The length of the vertical cables supporting the bottom wite cannot be adjusted, and these cables are positioned much farther apart. Alau imo intermediate ploata are Faatened to the write such as that there are no provision for representing the sag of the wire between cables.
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➢ is to determine minimum clear depths. They
locate obstruction and navigation danger in
confine areas such ag shwals. rock pinnades,
refers, or wreck. The sweep bar is a heavy
section. of tail road, steel pipe, or a atructural
ateel section. it is held by two vertical calde.
➢ is to determine minimum clear depths. They locate obstruction and navigation danger in confine areas such ag shwals. rock pinnades, refers, or wreck. The sweep bar is a heavy section. of tail road, steel pipe, or a atructural ateel section. it is held by two vertical calde.
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➢ Dredring in the process of widening,
enlarging, cleaning or deepening of channel
in harborn, rivers and canals.
➢ Dredring in the process of widening, enlarging, cleaning or deepening of channel in harborn, rivers and canals.
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➢ use when the excavation material are loaded
into rows which are towed to deep water
dumping site
➢ use when the excavation material are loaded into rows which are towed to deep water dumping site
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➢ pumps the material to low lying areas ashore
where it is ble al fill auch as in reclamation
projects
➢ pumps the material to low lying areas ashore where it is ble al fill auch as in reclamation projects
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➢ an a process, ig used to tomove the deposita
percolated underwater for the purpose of
clearing the water pathway for the ship to pass
to create bridges, dy leg, and damne
➢ an a process, ig used to tomove the deposita percolated underwater for the purpose of clearing the water pathway for the ship to pass to create bridges, dy leg, and damne
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➢ dredging process mainly involves carrying
out excavation of either naturally. deposited
sediment of manmade deleria such as rocks.
➢ dredging process mainly involves carrying out excavation of either naturally. deposited sediment of manmade deleria such as rocks.
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OLDEST KNOWN DREGING ACTIVITIES
OLDEST KNOWN DREGING ACTIVITIES
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➢ equipment used to remove the deposited
sediments from an inlet creeks, waterway of
ocean floor.
➢ equipment used to remove the deposited sediments from an inlet creeks, waterway of ocean floor.
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THREE INDEPENDENT ELEMENTS OF DREDGING
PROCESS
THREE INDEPENDENT ELEMENTS OF DREDGING PROCESS
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In __________ increase in trade at seas
necessitated the development of some bed
scratcher such as "_____________",
which was a primitive bed leveller
In __________ increase in trade at seas necessitated the development of some bed scratcher such as "_____________", which was a primitive bed leveller
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_____ were developed around _____, these
were a sort of dredging equipment which
was primarily employed for digging in ports.
Mills had a rotating chain connected with
wooden boards, these wooden boards dig up
the mud
_____ were developed around _____, these were a sort of dredging equipment which was primarily employed for digging in ports. Mills had a rotating chain connected with wooden boards, these wooden boards dig up the mud
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In ______ there came a revolutionary
development with the evolution of the design
of suction dredger by a French engineer. He
used successfully this suction dredger in
dredging the ___________. From then on,
dredging by suction became more and more
common.
In ______ there came a revolutionary development with the evolution of the design of suction dredger by a French engineer. He used successfully this suction dredger in dredging the ___________. From then on, dredging by suction became more and more common.
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IMPORTANCE OF DREDGING
IMPORTANCE OF DREDGING
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➢ is the process which sediments are picked up
using mechanical tools such as bucket, grabs
etc
➢ is the process which sediments are picked up using mechanical tools such as bucket, grabs etc
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➢ in this process of removing sediment from
the dreged site by using pumps usually
centrifugal pumps. sucked into pipe used to
transport the sediments
➢ in this process of removing sediment from the dreged site by using pumps usually centrifugal pumps. sucked into pipe used to transport the sediments
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➢ Reduces capital cost
➢ Safe and efficient
➢ Reduces use of equipment and transportation
➢ Hydrodynamic Dredging
➢ reduces energy and emissions compared to
mechanical dredging process
➢ Reduces capital cost ➢ Safe and efficient ➢ Reduces use of equipment and transportation ➢ Hydrodynamic Dredging ➢ reduces energy and emissions compared to mechanical dredging process
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➢ is fixed type stationary dredger which rotates
in are by winches around the cleging site. The
scrapping end is fitted with a bucket."
➢ is fixed type stationary dredger which rotates in are by winches around the cleging site. The scrapping end is fitted with a bucket."
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Launched by the United States of America in
___________ into a sun-synchronous orbit
around the Earth at an altitude of _______
➢ ___________ observatory weighing______ which circled the Earth ______________________
➢ The spacecraft was equipped with a
multispectral scanner which had the
capability to view a _______ wide strip of the
Earth's surface on an 18-day repetitive cycle.
➢ In ________, it was decided to rename ERTS to
Landsat.
Launched by the United States of America in ___________ into a sun-synchronous orbit around the Earth at an altitude of _______ ➢ ___________ observatory weighing______ which circled the Earth ______________________ ➢ The spacecraft was equipped with a multispectral scanner which had the capability to view a _______ wide strip of the Earth's surface on an 18-day repetitive cycle. ➢ In ________, it was decided to rename ERTS to Landsat.
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➢ AKA. Clamshell dredger a stationary dredger
which has a grab an a dredging tool
➢ AKA. Clamshell dredger a stationary dredger which has a grab an a dredging tool
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AKA. FIXED ARM DREDGER it's a stationary dredger which usually mounted on a barge of work neat the banks.
AKA. FIXED ARM DREDGER it's a stationary dredger which usually mounted on a barge of work neat the banks.
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➢ It is a stationary dredger normally used for
mining sand. The suction pipe of this dredger
is inserted into the sand deposit and water
jets are used to bring the sand up from the
excavation site. The sediment can be pumped
by sucking the sediments into the pipeline
and transferring it to the reclamation site or
loaded into barges, depending upon the
location and available transfer arrangement.
➢ It is a stationary dredger normally used for mining sand. The suction pipe of this dredger is inserted into the sand deposit and water jets are used to bring the sand up from the excavation site. The sediment can be pumped by sucking the sediments into the pipeline and transferring it to the reclamation site or loaded into barges, depending upon the location and available transfer arrangement.
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➢ It is another stationary dredger with a cutter
head as a dredging equipment to loosen the
base which is to be dredged. Similar to the
suction dredger, the sediments are sucked
and pumped via a pipeline ashore or into
barges. The cutter head can be of different
designs and materials, depending upon the
properties of the surface to be dredged
➢ It is another stationary dredger with a cutter head as a dredging equipment to loosen the base which is to be dredged. Similar to the suction dredger, the sediments are sucked and pumped via a pipeline ashore or into barges. The cutter head can be of different designs and materials, depending upon the properties of the surface to be dredged
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➢ This is a self-propelled ship carrying the
dredger equipment having a hold or hopper
arrangement to fill it with excavated material
while following a pre-set dredging operation.
This type of dredger has an arrangement to
open the bottom of the hold to unload the
dredged material into the designated site.
This kind of dredger is mainly used in open
water such as canals, rivers, estuaries etc
➢ This is a self-propelled ship carrying the dredger equipment having a hold or hopper arrangement to fill it with excavated material while following a pre-set dredging operation. This type of dredger has an arrangement to open the bottom of the hold to unload the dredged material into the designated site. This kind of dredger is mainly used in open water such as canals, rivers, estuaries etc
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➢ This is actually an assisting equipment in the
dredging operation and not a dredger itself. It
is used to empty the hopper barges
sediments using suction pipe which can be
lowered in the hopper barge hold. Additional
water can be sprayed to make the sediment
slurry for easier suction and transfer to the
dedicated site or shore depot
➢ This is actually an assisting equipment in the dredging operation and not a dredger itself. It is used to empty the hopper barges sediments using suction pipe which can be lowered in the hopper barge hold. Additional water can be sprayed to make the sediment slurry for easier suction and transfer to the dedicated site or shore depot
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➢ These ships have the unique constructional
feature of working out of the water surface
using long legs as their base. They can be
equipped with grabs, buckets or a shovel
installation
➢ These ships have the unique constructional feature of working out of the water surface using long legs as their base. They can be equipped with grabs, buckets or a shovel installation
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➢ This dredger uses high pressure air jets
instead of water jets for material flow at the
mouth of the suction pipe
➢ This dredger uses high pressure air jets instead of water jets for material flow at the mouth of the suction pipe
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➢ This type is used to level the bed surface
which has recently been dredged. It consists
of a long flat blade or heavy bar which is
connected to a tugboat at the end and when it
is pulled, it will level the surface on the
dredged surface over short distances.
➢ This type is used to level the bed surface which has recently been dredged. It consists of a long flat blade or heavy bar which is connected to a tugboat at the end and when it is pulled, it will level the surface on the dredged surface over short distances.
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➢ The quantity of material dredged from
anybody of water can be determined either
by sounding or scow measurements. Depth
measurement are obtained before and after
when soundings are used. The spacing of the
soundings will depend upon the smoothness
or irregularity of the bottom and upon the
difficulty of excavating material. Soundings
taken in tidal waters or in rivers at different
stages of the stream must be reduced to a
common datum
➢ The quantity of material dredged from anybody of water can be determined either by sounding or scow measurements. Depth measurement are obtained before and after when soundings are used. The spacing of the soundings will depend upon the smoothness or irregularity of the bottom and upon the difficulty of excavating material. Soundings taken in tidal waters or in rivers at different stages of the stream must be reduced to a common datum
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➢ The constructions of dams and reservoir
require extensive topographic and
hydrographic surveys. Dams are barriers
which are built to hold back or impound
water. The impounded water forms an
artificial lake or pond, called reservoir, in
which water is collected and stored usually
for purpose of irrigation, water supply, and
hydroelectric power production wand
transmission.
➢ The constructions of dams and reservoir require extensive topographic and hydrographic surveys. Dams are barriers which are built to hold back or impound water. The impounded water forms an artificial lake or pond, called reservoir, in which water is collected and stored usually for purpose of irrigation, water supply, and hydroelectric power production wand transmission.
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➢ The involvement of a civil engineer during
the early stages in the planning and
development of ports, wharves harbors, and
other marine structure is highly essential. His
task usually includes the preparation of plans
and design, supervision of all new marine
construction, the execution of related
hydrographic survey, and the subsequent
maintenance of existing marine structure.
➢ The involvement of a civil engineer during the early stages in the planning and development of ports, wharves harbors, and other marine structure is highly essential. His task usually includes the preparation of plans and design, supervision of all new marine construction, the execution of related hydrographic survey, and the subsequent maintenance of existing marine structure.
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Reasons if the discrepancy is unreasonably large:
Reasons if the discrepancy is unreasonably large:
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