ASTM D5073-02(2021)
(Practice)Standard Practice for Depth Measurement of Surface Water
Standard Practice for Depth Measurement of Surface Water
SIGNIFICANCE AND USE
5.1 This is a general practice intended to give direction in the selection of depth measuring procedures and equipment for use under a wide range of conditions encountered in surface water bodies. Physical conditions at the measuring site, the quality of data required, and the availability of appropriate measuring equipment govern the selection process. A step-by-step procedure for actually obtaining a depth measurement is not discussed. This practice is to be used in conjunction with a practice on positioning techniques and another practice on bathymetric survey procedures to obtain horizontal location and bottom elevations of points on a water body.
SCOPE
1.1 This practice guides the user in selection of procedures commonly used to measure depth in water bodies that are as follows:
Sections
Procedure A—Manual Measurement
6 through 11
Procedure B—Electronic Sonic-Echo Sounding
12 through 13
Procedure C—Electronic Nonacoustic Measurement
14 through 15
The text specifies depth measuring terminology, describes measurement of depth by manual and electronic equipment, outlines specific uses of electronic sounders, and describes an electronic procedure for depth measurement other than using sonar.
1.2 The references cited and listed at the end of this practice contain information that may help in the design of a high quality measurement program.
1.3 The information provided on depth measurement is descriptive in nature and not intended to endorse any particular item of manufactured equipment or procedure.
1.4 This practice pertains to depth measurement in quiescent or low-velocity flow. For depth measurement related to stream gauging, see Test Method D3858. For depth measurements related to reservoir surveys, see Guide D4581.
1.5 The values stated in inch-pound units are to be regarded as standard. The values given in parentheses are mathematical conversions to SI units that are provided for information only and are not considered standard.
1.6 This standard does not purport to address all of the safety concerns, if any, associated with its use. It is the responsibility of the user of this standard to establish appropriate safety, health, and environmental practices and determine the applicability of regulatory limitations prior to use.
1.7 This international standard was developed in accordance with internationally recognized principles on standardization established in the Decision on Principles for the Development of International Standards, Guides and Recommendations issued by the World Trade Organization Technical Barriers to Trade (TBT) Committee.
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Designation: D5073 − 02 (Reapproved 2021)
Standard Practice for
Depth Measurement of Surface Water
This standard is issued under the fixed designation D5073; the number immediately following the designation indicates the year of
original adoption or, in the case of revision, the year of last revision. A number in parentheses indicates the year of last reapproval. A
superscript epsilon (´) indicates an editorial change since the last revision or reapproval.
1. Scope mendations issued by the World Trade Organization Technical
Barriers to Trade (TBT) Committee.
1.1 This practice guides the user in selection of procedures
commonly used to measure depth in water bodies that are as
2. Referenced Documents
follows:
2.1 ASTM Standards:
Sections
D1129 Terminology Relating to Water
Procedure A—Manual Measurement 6 through 11
D3858 Test Method for Open-Channel Flow Measurement
Procedure B—Electronic Sonic-Echo Sounding 12 through 13
Procedure C—Electronic Nonacoustic Measurement 14 through 15
of Water by Velocity-Area Method
D4410 Terminology for Fluvial Sediment
The text specifies depth measuring terminology, describes
D4581 Guide for Measurement of Morphologic Character-
measurement of depth by manual and electronic equipment,
istics of Surface Water Bodies (Withdrawn 2013)
outlines specific uses of electronic sounders, and describes
an electronic procedure for depth measurement other than
3. Terminology
using sonar.
3.1 Definitions:
1.2 The references cited and listed at the end of this practice
3.1.1 For definitions of terms used in this standard, refer to
contain information that may help in the design of a high
Terminologies D1129 and D4410.
quality measurement program.
3.2 Definitions of Terms Specific to This Standard:
1.3 The information provided on depth measurement is
3.2.1 bar-check,n—amethodfordeterminingdepthbelowa
descriptive in nature and not intended to endorse any particular
survey vessel by means of a long, narrow metal bar or beam
item of manufactured equipment or procedure.
suspended on a marked line beneath a sounding transducer.
1.4 This practice pertains to depth measurement in quies-
3.2.2 bar sweep, n—a bar or pipes, suspended by wire or
cent or low-velocity flow. For depth measurement related to
cable beneath a floating vessel, used to search for submerged
stream gauging, see Test Method D3858. For depth measure-
snags or obstructions hazardous to navigation.
ments related to reservoir surveys, see Guide D4581.
3.2.3 beam width, n—theangleindegreesmadebythemain
1.5 The values stated in inch-pound units are to be regarded
lobe of acoustical energy emitted from the radiating face of a
as standard. The values given in parentheses are mathematical
transducer.
conversions to SI units that are provided for information only
3.2.4 bottom profile, n—a line trace of the bottom surface
and are not considered standard.
beneath a water body.
1.6 This standard does not purport to address all of the
3.2.5 sonar, n—a method for detecting and locating objects
safety concerns, if any, associated with its use. It is the
submerged in water by means of the sound waves they reflect
responsibility of the user of this standard to establish appro-
or produce.
priate safety, health, and environmental practices and deter-
3.2.6 sound, vt—to determine the depth of water (1).
mine the applicability of regulatory limitations prior to use.
3.2.7 sounding line, n—a rope or cable used for supporting
1.7 This international standard was developed in accor-
a weight while the weight is lowered below the water surface
dance with internationally recognized principles on standard-
to determine depth.
ization established in the Decision on Principles for the
Development of International Standards, Guides and Recom-
For referenced ASTM standards, visit the ASTM website, www.astm.org, or
contact ASTM Customer Service at service@astm.org. For Annual Book of ASTM
This practice is under the jurisdiction ofASTM Committee D19 on Water and Standards volume information, refer to the standard’s Document Summary page on
is the direct responsibility of Subcommittee D19.07 on Sediments, Geomorphology, the ASTM website.
and Open-Channel Flow. The last approved version of this historical standard is referenced on
CurrenteditionapprovedJuly1,2021.PublishedJuly2021.Originallyapproved www.astm.org.
in 1990. Last previous edition approved in 2013 as D5073 – 02 (2013). DOI: The boldface numbers in parentheses refer to a list of references at the end of
10.1520/D5073-02R21. this standard.
Copyright © ASTM International, 100 Barr Harbor Drive, PO Box C700, West Conshohocken, PA 19428-2959. United States
D5073 − 02 (2021)
3.2.8 sounding weight, n—a heavy object usually of lead, 6.2 Description of techniques and equipment are general in
that may be bell-shaped, for use in still water and soft bottom nature.Techniques and equipment may need to be modified for
materials or torpedo shaped with stabilizing fins, for use in use in specific field conditions.
flowing water.
7. Significance and Use
3.2.9 stray, n—spurious marks on the graphic depth records
7.1 Prior to the development of acoustic sounding
caused by surfaces other than the bottom surface of a water
equipment, manual techniques provided the only means of
body below the sounding vessel.
depth measurement. Some circumstances may still require
3.2.10 subbottom profile, n—a trace of a subsurface horizon
sounding by manual techniques such as shallow areas where
due to a change in the acoustic properties of the medium
depth is not sufficient for acoustic sounding. Manual proce-
through which the sound energy has traveled.
dures continue to serve several useful purposes such as the
3.2.11 towfish, n—a streamlined container, containing
following:
acoustical equipment for sounding depth, and designed to be
7.1.1 To search for and confirm the minimum depths over
pulled behind or beneath a survey vessel.
shallow area of sunken obstacles.
3.2.12 transducer, n—a device for translating electrical 7.1.2 To confirm bottom soundings in areas with submerged
energy to acoustical energy and acoustical energy back to vegetation, or other soft bottom materials.
electrical energy. 7.1.3 To assist in obtaining bottom samples.
7.1.4 To calibrate electronic sounding equipment.
3.2.13 transducer draft, n—the distance from the water
7.1.5 To suspend other measuring instruments to known
surface to the radiating face of a transducer.
depths for making various physical or chemical water quality
3.2.14 vertical control, n—a horizontal plane of reference
measurements (2).
used to convert measured depth to bottom elevation.
8. Sounding Rod (Manual Procedure)
4. Summary of Practices
8.1 The sounding rod (or sounding pole) can be used to
4.1 These practices include the following three general
measure depth over extensive flat, shallow areas more easily
techniques for acquiring depth measurements in surface water:
and more accurately than by other means. Use of the sounding
4.1.1 The first general technique is to determine depth by
rod should be restricted to still water or where the velocity is
manual procedures. The equipment to perform these proce-
relatively low, and to depths less than 12 ft (3.7 m). Sounding
dures may be most readily available and most practical under
rods are usually not used in depths over 6 ft (1.8 m) except to
certain conditions.
provide supplemental soundings to aid in interpreting analog
4.1.2 Thesecondgeneraltechniqueistodeterminedepthby
depth records. A weighted, flat shoe (see Fig. 1) should be
electronic sonic-echo sounding procedures. These procedures
attached to the bottom of the rod to prevent it from penetration
are most commonly used because of their reliability and the
of the bottom sediments.The rod may be graduated in feet and
variety of instruments available that meet specific measuring
tenths of a foot; zero being at the bottom of the shoe (3).
requirements.
4.1.3 The third general technique is to determine depth by
8.2 Modern sounding rods may be made of light-weight
an electronic procedure other than acoustic sounding. A pro- metals for strength, neutral buoyancy, and sound transmitting
cedure using ground penetrating radar is currently being used
capability. An experienced operator can measure the water
for measuring water depth for specific applications. depth and can distinguish the relative firmness of the bottom
material by the feel of the rod and the tone produced by the
5. Significance and Use
metal pole as it contacts the bottom (4).
5.1 This is a general practice intended to give direction in
8.3 When sounding in still water the operator should lower
the selection of depth measuring procedures and equipment for
therodintothewateruntilthebottomplatemakescontactwith
use under a wide range of conditions encountered in surface
the bottom surface. After determining that a firm bottom
water bodies. Physical conditions at the measuring site, the
material has been encountered, the water surface level is
quality of data required, and the availability of appropriate
visually read on the rod. When sounding in flowing water, to
measuring equipment govern the selection process. A step-by-
achieve vertical sounding, a long wire or cable anchored
step procedure for actually obtaining a depth measurement is
upstream and attached to the lower end of the rod may be
not discussed. This practice is to be used in conjunction with a
necessary.
practice on positioning techniques and another practice on
bathymetric survey procedures to obtain horizontal location
9. Sounding Line (Manual Procedure)
and bottom elevations of points on a water body.
9.1 The sounding line (see Fig. 2) can be used to measure
depthsoflargemagnitudebutisseldomusedfordepthsgreater
PROCEDURE A—MANUAL MEASUREMENT
than 15 ft (4.57 m). The sounding line should be of a material
6. Scope
that does not shrink or stretch, or lengthen from wear or
6.1 Thisprocedureexplainsthemeasurementofwaterdepth corrosion of the material as will occur in chain links over
using manual techniques and equipment.These include the use several years of use. Though manila rope and cotton, or other
of sounding rods, sounding lines, sounding reels, or a bar materials that require prestretching before use, have been
sweep. employed for large depths, small-diameter high-strength steel
D5073 − 02 (2021)
be used without introducing significant error. Depth indicators,
calibrated in either inch-pound or metric units, or both, are
available (5).
9.2 Markingsonthesoundinglineshouldbeeasytoseeand
understand to avoid making errors in determining the readings.
For sounding relatively shallow depths, marking at 0.5-ft
intervals with different colors to identify the 1, 2, and 10-ft
intervals is recommended. Care must be exercised so that the
first marker is the correct distance from the bottom of the
sounding weight when the weight is attached. When sounding,
depths are obtained from the difference in readings at an index
point on the bridge or boat rail, when the base of the sounding
weight is at the water surface, and when it is at the bottom. A
short steel tape or folding rule is usually employed to measure
the fractional distance from the line markers to the reference
point. Within the minimum 0.5-ft markings depths are esti-
mated and recorded to the nearest 0.1 ft. For sounding in deep
water, a sounding reel with depth indicator and an unmarked
high-strength steel cable is recommended (4).
9.2.1 When the metric system of units is used, the sounding
line for use in shallow depths is usually marked at 0.5-m
intervals with different colors to identify the 1 and 2-m
intervals. Depths are recorded to the nearest 0.01 m.
9.3 Weightsusedinsoundingareusuallyoflead,aluminum,
or brass. For application in still water, the weights are
FIG. 1 Graduated Sounding Rod with Shoe Attached
bell-shaped (see Fig. 3a) and made of cast aluminum or lead.
Theamountofweightshouldbefrom5to10lb(2.3to4.5kg).
9.3.1 For application in flowing water, the weight should be
of circular cross section and steamlined with fins (see Fig. 3b)
toturntheweightnosefirstintothecurrenttoofferaminimum
of resistance to the flow. The amount of weight should be
varied, depending on the water depth and flow velocity at a
cross section. A rule of thumb is that the weight in pounds
should be greater than the maximum product of velocity and
depth in the cross section. If debris or ice is flowing or the
stream is shallow or swift, use a heavier weight than the rule
designates. A variety of sizes of sounding weights from 15 to
300 lb (7 to 136 kg) should be available with appropriate
means of attaching to the sounding line (1). Sounding weights
should always be attached to the sounding line using a hanger
bar, clevis, snap hook, or thimble of brass or stainless steel to
protect the line from wear or damage.
9.4 The procedure for making soundings will vary depend-
ing on depth, current velocity, and means of locating where the
soundings are taken. Once at the location where a depth
measurement is needed, the basic procedure is to lower the
weight until the bottom of the weight is at the water surface.
When using a marked sounding line, the distance is read from
thesoundinglineatareferencepointonthebridgeorboatafter
which the weight is lowered to the bottom, and a new distance
FIG. 2 Sounding Line Used from Small Boat is read from the line and recorded.When using a sounding reel
the indicator is set to zero after which the weight is lowered to
the bottom and the depth is read and recorded. It is usually of
cable wound and released from a reel with a gear driven depth someimportance,especiallywhensoundinganunevenbottom,
indicator are readily available and greatly simplify the work to have the locations of the soundings accurately known
(1). The stretch of the high-strength cable is very small for its relative to the surroundings. When sounding from a boat using
intended use, and therefore, a considerable length of cable may weighted line, the boat should be stationary and should remain
D5073 − 02 (2021)
FIG. 4 Hand-operated Sounding Reel (1)
to allow the crank to be disengaged from the shaft while the
(a) Bell Shaped Sounding Weight (4)
wire is let out and engaged for reeling in. Various devices are
employed to drive a counter registering the amount of cable let
out from which the depth below water surface is determined.
These sounding reels may also be electrically driven, in that
case, they may have a depth capacity of more than 5000 ft
(1524 m) (1).
11. Bar Sweep (Manual Procedure)
11.1 The bar sweep is commonly used to search for and
locate any shoal or obstruction within or above navigation
depth that may pr
...
This document is not an ASTM standard and is intended only to provide the user of an ASTM standard an indication of what changes have been made to the previous version. Because
it may not be technically possible to adequately depict all changes accurately, ASTM recommends that users consult prior editions as appropriate. In all cases only the current version
of the standard as published by ASTM is to be considered the official document.
Designation: D5073 − 02 (Reapproved 2013) D5073 − 02 (Reapproved 2021)
Standard Practice for
Depth Measurement of Surface Water
This standard is issued under the fixed designation D5073; the number immediately following the designation indicates the year of
original adoption or, in the case of revision, the year of last revision. A number in parentheses indicates the year of last reapproval. A
superscript epsilon (´) indicates an editorial change since the last revision or reapproval.
1. Scope
1.1 This practice guides the user in selection of procedures commonly used to measure depth in water bodies that are as follows:
Sections
Procedure A—Manual Measurement 6 through 11
Procedure A—Manual Measurement 6 through 11
Procedure B—Electronic Sonic-Echo Sounding 12 through 13
Procedure B—Electronic Sonic-Echo Sounding 12 through 13
Procedure C—Electronic Nonacoustic Measurement 14 through 15
Procedure C—Electronic Nonacoustic Measurement 14 through 15
The text specifies depth measuring terminology, describes measurement of depth by manual and electronic equipment, outlines
specific uses of electronic sounders, and describes an electronic procedure for depth measurement other than using sonar.
1.2 The references cited and listed at the end of this practice contain information that may help in the design of a high quality
measurement program.
1.3 The information provided on depth measurement is descriptive in nature and not intended to endorse any particular item of
manufactured equipment or procedure.
1.4 This practice pertains to depth measurement in quiescent or low-velocity flow. For depth measurement related to stream
gaginggauging, see Test Method D3858. For depth measurements related to reservoir surveys, see Guide D4581.
1.5 The values stated in inch-pound units are to be regarded as standard. The values given in parentheses are mathematical
conversions to SI units that are provided for information only and are not considered standard.
1.6 This standard does not purport to address all of the safety concerns, if any, associated with its use. It is the responsibility
of the user of this standard to establish appropriate safety safety, health, and healthenvironmental practices and determine the
applicability of regulatory limitations prior to use.
1.7 This international standard was developed in accordance with internationally recognized principles on standardization
established in the Decision on Principles for the Development of International Standards, Guides and Recommendations issued
by the World Trade Organization Technical Barriers to Trade (TBT) Committee.
This practice is under the jurisdiction of ASTM Committee D19 on Water and is the direct responsibility of Subcommittee D19.07 on Sediments, Geomorphology, and
Open-Channel Flow.
Current edition approved Jan. 1, 2013July 1, 2021. Published January 2013July 2021. Originally approved in 1990. Last previous edition approved in 20072013 as
D5073 – 02 (2007).(2013). DOI: 10.1520/D5073-02R13.10.1520/D5073-02R21.
Copyright © ASTM International, 100 Barr Harbor Drive, PO Box C700, West Conshohocken, PA 19428-2959. United States
D5073 − 02 (2021)
2. Referenced Documents
2.1 ASTM Standards:
D1129 Terminology Relating to Water
D3858 Test Method for Open-Channel Flow Measurement of Water by Velocity-Area Method
D4410 Terminology for Fluvial Sediment
D4581 Guide for Measurement of Morphologic Characteristics of Surface Water Bodies (Withdrawn 2013)
3. Terminology
3.1 Definitions—Definitions: For definition of terms used in this practice refer to Terminologies D1129 and D4410.
3.1.1 For definitions of terms used in this standard, refer to Terminologies D1129 and D4410.
3.2 Definitions of Terms Specific to This Standard:
3.2.1 bar-check, n—a method for determining depth below a survey vessel by means of a long, narrow metal bar or beam
suspended on a marked line beneath a sounding transducer.
3.2.2 bar sweep, n—a bar or pipes, suspended by wire or cable beneath a floating vessel, used to search for submerged snags or
obstructions hazardous to navigation.
3.2.3 beam width, n—the angle in degrees made by the main lobe of acoustical energy emitted from the radiating face of a
transducer.
3.2.4 bottom profile, n—a line trace of the bottom surface beneath a water body.
3.2.5 sonar, n—a method for detecting and locating objects submerged in water by means of the sound waves they reflect or
produce.
3.2.6 sound, vt—to determine the depth of water (1).
3.2.7 sounding line, n—a rope or cable used for supporting a weight while the weight is lowered below the water surface to
determine depth.
3.2.8 sounding weight, n—a heavy object usually of lead, that may be bell-shaped, for use in still water and soft bottom materials
or torpedo shaped with stabilizing fins, for use in flowing water.
3.2.9 stray, n—spurious marks on the graphic depth records caused by surfaces other than the bottom surface of a water body
below the sounding vessel.
3.2.10 subbottom profile, n—a trace of a subsurface horizon due to a change in the acoustic properties of the medium through
which the sound energy has traveled.
3.2.11 towfish, n—a streamlined container, containing acoustical equipment for sounding depth, and designed to be pulled behind
or beneath a survey vessel.
3.2.12 transducer, n—a device for translating electrical energy to acoustical energy and acoustical energy back to electrical energy.
3.2.13 transducer draft, n—the distance from the water surface to the radiating face of a transducer.
For referenced ASTM standards, visit the ASTM website, www.astm.org, or contact ASTM Customer Service at service@astm.org. For Annual Book of ASTM Standards
volume information, refer to the standard’sstandard’s Document Summary page on the ASTM website.
The last approved version of this historical standard is referenced on www.astm.org.
The boldface numbers in parentheses refer to a list of references at the end of this practice.standard.
D5073 − 02 (2021)
3.2.14 vertical control, n—a horizontal plane of reference used to convert measured depth to bottom elevation.
4. Summary of Practices
4.1 These practices include the following three general techniques for acquiring depth measurements in surface water:
4.1.1 The first general technique is to determine depth by manual procedures. The equipment to perform these procedures may
be most readily available and most practical under certain conditions.
4.1.2 The second general technique is to determine depth by electronic sonic-echo sounding procedures. These procedures are
most commonly used because of their reliability and the variety of instruments available that meet specific measuring requirements.
4.1.3 The third general technique is to determine depth by an electronic procedure other than acoustic sounding. A procedure using
ground penetrating radar is currently being used for measuring water depth for specific applications.
5. Significance and Use
5.1 This is a general practice intended to give direction in the selection of depth measuring procedures and equipment for use
under a wide range of conditions encountered in surface water bodies. Physical conditions at the measuring site, the quality of data
required, and the availability of appropriate measuring equipment govern the selection process. A step-by-step procedure for
actually obtaining a depth measurement is not discussed. This practice is to be used in conjunction with a practice on positioning
techniques and another practice on bathymetric survey procedures to obtain horizontal location and bottom elevations of points
on a water body.
PROCEDURE A—MANUAL PROCEDURE A—MANUAL MEASUREMENT
6. Scope
6.1 This procedure explains the measurement of water depth using manual techniques and equipment. These include the use of
sounding rods, sounding lines, sounding reels, or a bar sweep.
6.2 Description of techniques and equipment are general in nature. Techniques and equipment may need to be modified for use
in specific field conditions.
7. Significance and Use
7.1 Prior to the development of acoustic sounding equipment, manual techniques provided the only means of depth measurement.
Some circumstances may still require sounding by manual techniques such as shallow areas where depth is not sufficient for
acoustic sounding. Manual procedures continue to serve several useful purposes such as the following:
7.1.1 To search for and confirm the minimum depths over shallow area of sunken obstacles.
7.1.2 To confirm bottom soundings in areas with submerged vegetation, or other soft bottom materials.
7.1.3 To assist in obtaining bottom samples.
7.1.4 To calibrate electronic sounding equipment.
7.1.5 To suspend other measuring instruments to known depths for making various physical or chemical water quality
measurements (2).
8. Sounding Rod (Manual Procedure)
8.1 The sounding rod (or sounding pole) can be used to measure depth over extensive flat, shallow areas more easily and more
accurately than by other means. Use of the sounding rod should be restricted to still water or where the velocity is relatively low,
and to depths less than 12 ft (3.7 m). Sounding rods are usually not used in depths over 6 ft (1.8 m) except to provide supplemental
D5073 − 02 (2021)
soundings to aid in interpreting analog depth records. A weighted, flat shoe (see Fig. 1) should be attached to the bottom of the
rod to prevent it from penetration of the bottom sediments. The rod may be graduated in feet and tenths of a foot; zero being at
the bottom of the shoe (3).
8.2 Modern sounding rods may be made of light-weight metals for strength, neutral buoyancy, and sound transmitting capability.
An experienced operator can measure the water depth and can distinguish the relative firmness of the bottom material by the feel
of the rod and the tone produced by the metal pole as it contacts the bottom (4).
8.3 When sounding in still water the operator should lower the rod into the water until the bottom plate makes contact with the
bottom surface. After determining that a firm bottom material has been encountered, the water surface level is visually read on the
rod. When sounding in flowing water, to achieve vertical sounding, a long wire or cable anchored upstream and attached to the
lower end of the rod may be necessary.
9. Sounding Line (Manual Procedure)
9.1 The sounding line (see Fig. 2) can be used to measure depths of large magnitude but is seldom used for depths greater than
15 ft (4.57 m). The sounding line should be of a material that does not shrink or stretch, or lengthen from wear or corrosion of
the material as will occur in chain links over several years of use. Though manila rope and cotton, or other materials that require
prestretching before use, have been employed for large depths, small-diameter high-strength steel cable wound and released from
a reel with a gear driven depth indicator are readily available and greatly simplify the work (1). The stretch of the high-strength
cable is very small for its intended use, and therefore, a considerable length of cable may be used without introducing significant
error. Depth indicators, calibrated in either inch-pound or metric units, or both, are available (5).
9.2 Markings on the sounding line should be easy to see and understand to avoid making errors in determining the readings. For
sounding relatively shallow depths, marking at 0.5-ft intervals with different colors to identify the 1, 2, and 10-ft intervals is
recommended. Care must be exercised so that the first marker is the correct distance from the bottom of the sounding weight when
the weight is attached. When sounding, depths are obtained from the difference in readings at an index point on the bridge or boat
rail, when the base of the sounding weight is at the water surface, and when it is at the bottom. A short steel tape or folding rule
is usually employed to measure the fractional distance from the line markers to the reference point. Within the minimum 0.5-ft
FIG. 1 Graduated Sounding Rod with Shoe Attached
D5073 − 02 (2021)
FIG. 2 Sounding Line Used from Small Boat
markings depths are estimated and recorded to the nearest 0.1 ft. For sounding in deep water, a sounding reel with depth indicator
and an unmarked high-strength steel cable is recommended (4).
9.2.1 When the metric system of units is used, the sounding line for use in shallow depths is usually marked at 0.5-m intervals
with different colors to identify the 1 and 2-m intervals. Depths are recorded to the nearest 0.01 m.
9.3 Weights used in sounding are usually of lead, aluminum, or brass. For application in still water, the weights are bell-shaped
(see Fig. 3a)a) and made of cast aluminum or lead. The amount of weight should be from 5 to 10 lb (2.3 to 4.5 kg).
9.3.1 For application in flowing water, the weight should be of circular cross section and steamlined with fins (see Fig. 3b)b) to
turn the weight nose first into the current to offer a minimum of resistance to the flow. The amount of weight should be varied,
depending on the water depth and flow velocity at a cross section. A rule of thumb is that the weight in pounds should be greater
than the maximum product of velocity and depth in the cross section. If debris or ice is flowing or the stream is shallow or swift,
use a heavier weight than the rule designates. A variety of sizes of sounding weights from 15 to 300 lb (7 to 136 kg) should be
available with appropriate means of attaching to the sounding line (1). Sounding weights should always be attached to the sounding
line using a hanger bar, clevis, snap hook, or thimble of brass or stainless steel to protect the line from wear or damage.
9.4 The procedure for making soundings will vary depending on depth, current velocity, and means of locating where the
soundings are taken. Once at the location where a depth measurement is needed, the basic procedure is to lower the weight until
the bottom of the weight is at the water surface. When using a marked sounding line, the distance is read from the sounding line
at a reference point on the bridge or boat after which the weight is lowered to the bottom, and a new distance is read from the line
and recorded. When using a sounding reel the indicator is set to zero after which the weight is lowered to the bottom and the depth
is read and recorded. It is usually of s
...
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