Reconnaissance for Hydrographic Survey Project The system is able to withstand the harsh environment of the nearshore and acquire beach profile information across the surf zone. This paper describes the system and results of a comparison in Myrtle Beach, S.C., between surveys collected over a 3- day period by the personal watercraft system and by a similar system mounted aboard a traditional coastal survey vessel. The bathymetric measurements for the personal watercraft-mounted echosounder surveying system display mean repetitive differences of 6 cm. This workshop is an introductory course in Hydrographic surveying. It is designed for surveyors, engineers, survey technicians, dredge operators, and hydrographers. The course focuses on theoretical principles of hydrographic surveying, project description, operation, and map production.

1. (Reconnaissance for Hydrographic
Survey Project)
Student Name: Copyright
Class: 4th
stage
Course Title: Hydrographic survey
Department: Geomatics (Surveying)
Collage of Engineering
Salahaddin United -Erbil
Academic Year 2019-2020

2. 2
ABSTRACT
A hydrographic surveying system has been designed and tested to acquire
nearshore beach profile data. Traditional vessel-mounted echosounder sur-veying
instrumentation was placed in watertight containers and configured for a personal
watercraft for measurements of subaqueous nearshore beach profiles.
The system is able to withstand the harsh environment of the nearshore and acquire
beach profile information across the surf zone. This paper describes the system and
results of a comparison in Myrtle Beach, S.C., between surveys collected over a 3-
day period by the personal watercraft system and by a similar system mounted
aboard a traditional coastal survey vessel.
The bathymetric measurements for the personal watercraft-mounted echosounder
surveying system display mean repetitive differences of 6 cm.
This workshop is an introductory course in Hydrographic surveying.
It is designed for surveyors, engineers, survey technicians, dredge operators, and
hydrographers.
The course focuses on theoretical principles of hydrographic surveying, project
description, operation, and map production.

3. 3
TABLE OF CONTENT
Abstract………………………………………………….2
Table of content …………………………………….….…3
Introduction…………………………………………..……4
Methods of hydrographic survey……………………....….6
Uses of Hydrographic Surveying…………………………7
Basic measurement and survey equipment………….……8
Depth sounding equipment……………………………....10
Survey standard and procedures……………………….…11
Conventional (manual) method ……………………….…12
Sources of errors on depth measurements…………….….14
Vertical datum and positioning………………….……….15
Survey coverage and resolution……………….…………18
Conclusion…………………………………………….…20
Reference……………………………………………..….21

4. 4
INTRODUCTION
More than half of the world’s population lives within 100 km of
its shores. The effects of denser coastal population and accelerating
climate change can be seen in degraded (and even disappearance of)
ecosystems, coastal erosion, over-fishing, marine pollution, and higher
vulnerability to marine disasters such as tsunami or volcanic activity.
Marine environments (oceans, lake, rivers, swamps, wetlands)
cover more than two-thirds of the Earth’s surface, and are not easily
accessible to direct observations. In the past 20 to 30 years
technological advances have allowed us to discover and map much more
detailed coastal and ocean bathymetry and to delineate shore boundaries,
mostly through acoustic remote sensing.
Hydrography is that branch of physical oceanography that deals
with measurement and definition of the configuration of the bottoms and
adjacent land area of oceans, lakes, harbors, and other water bodies on
Earth. Hydrographic surveying, in the strictest sense, is defined merely as
the surveying of a water area;however, in modern usageit mayinclude a
widevarietyof other objectives such as measurements of tides, currents,
gravity, and the determination of physical and chemical properties of
water.
The principal objective of most hydrographic surveys that are conducted
by large government agencies like the National Oceanic and
Atmospheric Administration (NOAA) is to produce nautical charts and
mapping.
NOAA uses very large vessels to obtain basic data for the compilation
of nautical charts with emphasis on features that affect safe navigation.
Other objectives of NOAA include acquiring the information necessary
to produce related marine navigational products for coastal zone
management, engineering, and scientific investigations.
Other government agencies such as the US Army Corp of Engineers
(USACE), the Naval Oceanographic Office (NAVO), the US
Geological Survey (USGS), are tasked with hydrographic surveys for a
variety of purposes Some state and local agencies as well as the private
sector also have hydrographic survey capabilities.

5. 5
The US Army Corps of Engineers (USACE) is responsible to collect,
process, and map hydrographic survey data for federally authorized civil
and military navigation channels and shore protection projects
throughout the US including Puerto Rico and the Virgin Islands. The
main purpose of collecting hydrographic survey data is to be used by
engineers and scientists to monitor channel shoaling conditions. Survey
results in the form of a bathymetric map become a decision making tool
for channel maintenance operations, channel deepening contracts,
planning studies.
figure 1: hydrographic survey
Applications of Hydrographic Surveying
1. Dock and Harbor Engineering
2. Irrigation
3. River Works
4. Land reclamation
5. Water Power
6. Flood Control
7.SewageDisposal

6. 6
METHODS OF THE HYDROGRAPHIC SURVEY
Figure 2: methods of hydrographic survey

7. 7
Uses of Hydrographic Surveying
Uses of hydrographic surveying are given below
1.Depth of the bed can be determined.
2. Shore lines can be determined.
3. Navigation Chart Preparation.
4. Locate sewer fall by measuring direct currents.
5. Locating mean sea level.
6. Scouring, silting and irregularities of the bed can be identified.
7. Tide measurement.
8. River and stream discharge measurement.
9. Massive-structures like bridges, dam’s harbors are planned.
IMPORTANCE OF ESTABLISHING HYDROGRAPHIC:
• Act as the national agency for hydrography within Solomon Islands
Government
• Discharge the nations responsibility under SOLAS.
• Carry out, as far as possible:
1. Nautical and hydrographic services, in the manner most suitable for
the purpose of aiding navigational.
2. Hydrographic survey is carried out, as far as possible, adequate to the
requirements of safe navigation.
3. Prepare nautical charts, sailing directions, lists of lights, tide tables
and other nautical publications, where applicable, satisfy needs of safe
navigation.
4. Issue nautical charts.
5. Promulgate notices to mariners in order that nautical charts and
publications are kept, as far as possible, up to date.
6. Provide data management arrangements to support these services.
7. Further Readings – IHO Publication M‐2 available on Website.

8. 8
BASIC MEASUREMENT and SURVEY EQUIPMENT
The basic measurement for hydrographic surveys is depth measurements.
Depth measurement during the pre-1920’s was very rudimentary. The
photograph shows a surveyor who is handling a depth measurement or sample
sound calibration measurements.
Planning and design of the hydrographic survey must produce an accurate and
reliable chart derived from sufficient data coverage. illustrates the basic
elements for designing a survey. The design of the survey must produce an
accurate and reliable chart derived from sufficient data coverage. For
example, the production of the bathymetric contour depends on spatial
resolution. By definition, the resolution (S) describes how close two objects
can be and still be determined unambiguously.
Hydrographic surveying (for dredging operations or bathymetric mapping) involves
synergy of three major surveying units. Three major components of hydrographic
surveying include the marine vessel that carries the crew and supplies, the
geodetic positioning technology, and the depth measuring equipment.
Marine Vessel
The size and payload of the marine vessel depends on the extent of the
survey project requirements. Surveys can be classified by vessel size -small
scale (from wading to small boats), medium scale (using medium size boats
and acoustic methods), and regional scale surveys using deep sea research
vessels with state-of-the art multi-disciplinary data collection systems.
Essential equipment list for each survey is as follows;
A) Small Surveys:
1. Vessel: Oars, Life jackets, Gas tanks (minimum 2), extra oil, and 10 HP engine
2. Depth and Position: 50’ lead-line, range poles, and plans. Survey
equipment may include Total Station Instrument (TSI), compensating
level as required, prism pole with extension rods. Deeper water requires a
Fathometer and transducer installation.
3. Miscellaneous: Radio, 300 ft tape, Navigation chart, staff sheets,
Batteries (2), repair kit, tool box
B) Medium Scale Surveys:
1. Vessel: 25-65 ft vessel, licensed operator.
2. Depth and Position: Echo sounder with Transducer and adequate power
from batteries or generator, tool box, transducers, GPS or TSI

9. 9
positioning, motion reference units (MRU)
3. Miscellaneous: A small vessel for the near-shore shallow water survey
system to perform as rover platform.
C) Regional Scale Surveys:
1. Vehicle: 65 ft and larger research vessels, with competent crew and equipment.
2. Depth and Position: Multi-beam transducer and GPS.
3. Other Equipment: Cameras for stereo imaging (require positioning of
frames) Integrated multi-disciplinary data collection systems (e.g.
gravity magnetics) requires accurate in-ship surveys for sensor
integration, calibration, and synchronization.
POSITIONING EQUIPMENT
Offshore positioning equipment has revolutionized due to dramatic
evolution in sensor technology and computer science. Traditional offshore
equipment includes a sextant transit, stadia, and an electronic distance
measuring (EDM) device. Nowadays, several methods for horizontal
positioning include optical, land-based electronic ranging, and space-based
positioning.
A basic method of positioning is the resection However, the positioning
methodology employed on any project will be evaluated based on site-specific
conditions and project specifications.
The preferred method of positioning for-offshore surveys is GPS. Wide-and
narrow -lane GPS observations have proven to be the most efficient and cost
effective for offshore hydrographic surveys.
Figure3: Acoustic depth measurement

10. 10
DEPTH SOUNDING EQUIPMENT
A transducer initiates a sonic pulse. The sound wave propagates
through the water and a receiver detects the return pulse. A basic technique of
depth measurement is using a Single Beam Echo Sounder (SBES). An echo
sounder performs the following operations;
• Transmit Sound
• Measure round trip travel time.
• Use sound speed to get distance
The depth (or distance) is computed from the two-way travel time as
…... (1)
The transducer interfaces with the depth sounder which outputs a profile
of the bathymetry or “bottom return”. Two important components of depth
sounding equipment include the frequency and the beam divergence (or cone
angle).
Frequency
Most single frequency sonar units operate in the range of about 24 - 210
kHz (kilohertz). A few are dual frequency capable, meaning they can use both
50 and 200 kHz transducers. Typically, high frequency (192 or 200 kHz) sonar
units provide the best resolution and definition of submerged structures and
targets. 50 kHz units have much greater depth penetration capability, but show
less definition. 24 kHz transducers also have a much wider cone angle than
192 or 210 kHz transducers.
It is critical to match the transducer's frequency to that of the sonar unit.
For example, a 192 kHz sonar unit requires a 192 kHz transducer.
Acoustic Parameters (Instrument Specific)
Characteristics of echo sounders are determined by transducer;
1) Directivity
2) Beam width
3) Beam steering and side lobes
Distance 
time  speed

11. 11
SURVEY STANDARDS and PROCEDURE
Traditional hydrographic survey, in its most basic form, is an open-
ended traverse. Horizontal positioning has no independent check –
therefore the survey precision depends on the measuring method used.
The vertical accuracy is more uncontrolled due to variable physical
properties of the water column and the characteristic (morphology and
type) of the bottom.
shows the corrections that should be applied to acoustic depth
measurements.
figure 4: corrections to acoustic depth measurement
Instantaneous Sea
Surface
Dynamic Transducer
Draft Correction
Tide Corrn
Observed
Depth
Actual
Depth
Sound Velocity
Correction
Chart
Depth

12. 12
CONVERSATIONAL (MANUAL) METHODS
The simplest approach uses a winch-powered Tagline for range
measurements and a Lead Line Chain, with a weight attached, for depth
measurement. The tag line is anchored on the shore. Another
conventional method of depth (bathymetry) determination involves the
use of range pole, small floating platform (e.g., raft, boat, etc.), and transit.
Figure 5: illustrates the basic set up using a prism-mounted range pole.
Figure5: Conventional Bathymetric Surveying
Acoustic Depth Determination Method
Acousticmethods onwaterdepths determination requires specific
knowledgeofthephysical oceanography
1.1 underwater acoustics
1.2 VesselAttitude
andHeave
measurements
Measurement Calibration
1. Sound velocity Profiler to measurethevelocityversus depth (z)
through the water column
2. electronicinstrument(CTD) to measure conductivity, temperature,
and depth(z)
3. Other complex methods
beyond the scope of this workshop
Underwaterrangemeasurements areobtainedfrom Sound Navigation and
Ranging(SONAR)
Range pole
TSI
BM
SEDIMENT
Water Surface

13. 13
Figure6: Survey Boat with Acoustic Measuring Equipment
Principles of Single Beam Echo Sounding (SBES)
The transducer transmits acoustic energy into the water in the form of a
vertically oriented beam. Reflected energy (i.e., echo) is sensed by the
transducer. The measured depth (z) is given as;
z(m) =1/2. t*c…. (2
t is the time interval (in seconds) between pulse
where c is the velocity of sound in water column transmission and echo reception.

14. 14
SOURCES of ERRORS on DEPTH MEASUREMENT
1) Bottom slop (and roughness). The quantity (dz) depends on beam width and
slope
2) Sound velocity variation (spatio-temporal variation)
3) Time measurement
4) Attitude of vessel
5) Draft: transducer draft depends on coverage load during the survey (fuel and
water consumption during survey will results in variation in measurement) is a
function of the float area at sea surface
6) Recording errors – analogue versus digital.
Depth Reduction equation is given as;
where DC
 d0  VD  CSVCHVCT …….(3)
DC is the final charted depth
d0 is the uncorrected depth observation
VD is the change in vessel draft
CSV is the sound velocity correction
CHV
is the total vessel heave correction?
CT is the tidal height correction
Tidal reduction for the vertical datum (co-tidal model or weighted average of the
tide Gauge (TG) measurement

15. 15
VERTICAL DATUM and POSITIONING
• Geodetic Vertical Datum • Tidal Datums • Sea Surface, Lakes, and River Levels
In Figure 6 the elevation and state of the Instantaneous Sea Surface Topography
(ISST) is induced by various factors including wind, tides, and currents.
Hydrographic surveys provide depth from ISST and bathymetric contours relative
to a vertical datum. The bathymetric survey datum is the North American Vertical
Datum. A vertical datum is a geodetic datum - established by adjustment of
orthometric leveling nets. It is a reference (surface) for national vertical control
networks. Vertical datums include the NGVD of 1929 called the NGVD29.
NGVD29 is derived from adjustment of 1st order level nets of US and Canada –
21Tidegagues (TGs) (US) and 5 TG’s (Canada) held fixed. Comparison between
the NAVD29 and MSL reveals spatio-temporal variations due to
1. Many unaccounted for physical variables affecting sea level
2. MSL is hourly average height over 19yr period of observations
3. Non-linear relationship between mean tide level (MTL) and NGVD29
4. monthly MTL (planes) changes due to major seasonal changes resulting from
barometric pressure, steric level, river discharge and wind effects
Figure 7: geodetic datums and sea level

16. 16
TIDAL DATUM
A plane of reference derived from rise/fall of oceanic tides. Various datum
planes: Mean Higher High Water (MHHW), Mean High Water (MHW), Mean Sea
Level (MSL), Mean Tidal Level (MTL), Mean Lower Water (MLW), and Mean
Lower Low Water (MLLW).
Datums relative to a specific time (i.e., Epoch) can be determined; located on the
ground and mapped. Datums can be determined by observations when needed (i.e.,
settle dispute, engineering projects, or scientific investigation). Tidal Datum (TD)
are used for engineering projects, coastal boundary delineation, and nautical
charting
(Q. What is the relationship of a TD to the NAVD?)
1) Engineering Design
• TD defined by the low water - for safe under keel clearance for safe ship
navigation in harbors
• TD required for design of structures in coastal regions including jetty
reconstruction, dredging for under keel clearance, ship navigation, and beach
replenishment etc.,
2) Seaward boundary mapping
• Establish Seaward Boundary for
1. Offshore oil industry required definition of federal boundary for tax claim
revenue purpose
2. Private-State boundary delineation definition due to coastline variations
Shoreline: is the intersection of the TD plane with respect to the coast (beach
topography). A Tidal boundary is defined by local TD. The amount of error in the
Tidal datum (eTD) determination and the slope angle (α) of beach have
considerable influence in delineating the true location of the shoreline boundary
(figure 8). The relationship of the error in the shore boundary error line (SBL) and
the beach topography is described as
eSBL =eTD cot(α)……(4)

17. 17
Figure8: seaward boundary and tidal datum
Example: Compute the error in the seaward boundary line (SBL) due to TD error
of 1 ft on a beach slope of 5 degrees
Solution:
eSBL=1.0×cot (50) = 11.4 ft…. (5)
3) Nautical Charting
Tide determination by GPS observations is not straightforward. However, RTK
provides convenience in the form of
b=∆hGPS +F−a …. (6)
where b is the height different between the BM and the Chart datum, a is the GPS
antenna height, is the ∆hGPS is the geometric height difference between the GPS
receiver and the geodetic BM, and Fis the height from the GPS antenna to the
transducer. Tide (T) is given by
T =a+b−∆hGPS –F…... (7)

18. 18
SURVEY COVERAGE and RESOLUTION
The spacing between stations is project and site specific.
For example, a 50-ft nominal grid spacing interval spacing may be insufficient to
map the structural or morphological details of an unexpected submerged structure
or dumping mound.
Higher spatial resolution sounding may be required in the vicinity of the feature to
be mapped.
Single beam line spacing may vary from 10 feet to over 1000 feet. Lines run in the
opposite direction may also be required to fully define an area or for QC purposes.
Multibeam line spacing may vary due to depth, beam angle, and overlap required.
For example, if 45 degree either side of nadir is used, the coverage will be 2x the
water depth.
COAST LINE
EnsonifiedSeafloorArea
SurveyVessel
Figure9:SurveyDesignandFieldCampaignforSinglebeam
lines”) TracksVoyage (“Tag

19. 19
figure 10: survey design and filed campaign sweep multibeam surveys

20. 20
CONCLUSION
The development of Water Transportation can be determined by the conduct
of Hydrographic Surveying as this activity will be of high significance to
National Development of a country.
Need to create the awareness in the importance of hydrographic
surveying to determine the safety in the use of the water body for
transportation.
Water Transportation System can be one of the cost effective and
safest modes of transportation in iraq and its development can
be made possible by the conduction of a hydrographic survey to
determine the topography of the water body.

21. 21
REFERENCE
1.http://www.fao.org/3/i1883e/i1883e05.pdf.
2.Surv. Isaac Larbie ,Geomatic Engineer, Survey and Mapping Division.
3.dr. Laramie v. potts and mr. Stephen Farrell ( hydrocraphic surveying ) 2011.
4.https://en.wikipedia.org/wiki/Hydrographic_survey.