ASTM D5243-92(2019)
(Test Method)Standard Test Method for Open-Channel Flow Measurement of Water Indirectly at Culverts
Standard Test Method for Open-Channel Flow Measurement of Water Indirectly at Culverts
SIGNIFICANCE AND USE
5.1 This test method is particularly useful to determine the discharge when it cannot be measured directly with some type of current meter to obtain velocities and sounding equipment to determine the cross section. See Test Method D3858.
5.2 Even under the best of conditions, the personnel available cannot cover all points of interest during a major flood. The engineer or technician cannot always obtain reliable results by direct methods if the stage is rising or falling very rapidly, if flowing ice or debris interferes with depth or velocity measurements, or if the cross section of an alluvial channel is scouring or filling significantly.
5.3 Under flood conditions, access roads may be blocked, cableways and bridges may be washed out, and knowledge of the flood frequently comes too late. Therefore, some type of indirect measurement is necessary. The use of culverts to determine discharges is a commonly used practice.
SCOPE
1.1 This test method covers the computation of discharge (the volume rate of flow) of water in open channels or streams using culverts as metering devices. In general, this test method does not apply to culverts with drop inlets, and applies only to a limited degree to culverts with tapered inlets. Information related to this test method can be found in ISO 748 and ISO 1070.
1.2 This test method produces the discharge for a flood event if high-water marks are used. However, a complete stage-discharge relation may be obtained, either manually or by using a computer program, for a gauge located at the approach section to a culvert.
1.3 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.
1.4 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.
1.5 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.
General Information
Relations
Standards Content (Sample)
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.
Designation: D5243 −92 (Reapproved 2019)
Standard Test Method for
Open-Channel Flow Measurement of Water Indirectly at
Culverts
This standard is issued under the fixed designation D5243; the number immediately following the designation indicates the year of
original adoption or, in the case of revision, the year of last revision.Anumber in parentheses indicates the year of last reapproval.A
superscript epsilon (´) indicates an editorial change since the last revision or reapproval.
1. Scope D2777Practice for Determination of Precision and Bias of
Applicable Test Methods of Committee D19 on Water
1.1 This test method covers the computation of discharge
D3858Test Method for Open-Channel Flow Measurement
(the volume rate of flow) of water in open channels or streams
of Water by Velocity-Area Method
using culverts as metering devices. In general, this test method
2.2 ISO Standards:
does not apply to culverts with drop inlets, and applies only to
ISO 748Liquid Flow Measurements in Open Channels-
a limited degree to culverts with tapered inlets. Information
Velocity-Area Methods
related to this test method can be found in ISO 748 and ISO
ISO 1070Liquid Flow Measurements in Open Channels-
1070.
Slope-Area Methods
1.2 This test method produces the discharge for a flood
event if high-water marks are used. However, a complete
3. Terminology
stage-discharge relation may be obtained, either manually or
3.1 Definitions:
by using a computer program, for a gauge located at the
3.1.1 For definitions of terms used in this standard, refer to
approach section to a culvert.
Terminology D1129.
1.3 The values stated in inch-pound units are to be regarded
3.2 Several of the following terms are illustrated in Fig. 1.
as standard. The values given in parentheses are mathematical
3.3 Definitions of Terms Specific to This Standard:
conversions to SI units that are provided for information only
3.3.1 alpha (α), n—a velocity-head coefficient that adjusts
and are not considered standard.
thevelocityheadcomputedonbasisofthemeanvelocitytothe
1.4 This standard does not purport to address all of the
truevelocityhead.Itisassumedequalto1.0ifthecrosssection
safety concerns, if any, associated with its use. It is the
is not subdivided.
responsibility of the user of this standard to establish appro-
priate safety, health, and environmental practices and deter- 3.3.2 conveyance (K), n—ameasureofthecarryingcapacity
of a channel and having dimensions of cubic feet per second.
mine the applicability of regulatory limitations prior to use.
1.5 This international standard was developed in accor- 3.3.2.1 Discussion—Conveyance is computed as follows:
dance with internationally recognized principles on standard-
1.486
2/3
K 5 R A
ization established in the Decision on Principles for the
n
Development of International Standards, Guides and Recom-
where:
mendations issued by the World Trade Organization Technical
n = the Manning roughness coefficient,
Barriers to Trade (TBT) Committee.
2 2
A = the cross section area, in ft (m ), and
2. Referenced Documents R = the hydraulic radius, in ft (m).
2.1 ASTM Standards:
3.3.3 cross sections, n—(numbered consecutively in down-
D1129Terminology Relating to Water stream order):
3.3.3.1 The approach section, Section 1, is located one
culvert width upstream from the culvert entrance.
This test method is under the jurisdiction of ASTM Committee D19 on Water
3.3.3.2 Cross Sections 2 and 3 are located at the culvert
and is the direct responsibility of Subcommittee D19.07 on Sediments,
Geomorphology, and Open-Channel Flow. entrance and the culvert outlet, respectively.
Current edition approved Nov. 1, 2019. Published January 2020. Originally
3.3.3.3 Subscripts are used with symbols that represent
approved in 1992. Last previous edition approved in 2013 as D5243–92 (2013).
cross sectional properties to indicate the section to which the
DOI: 10.1520/D5243-92R19.
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’s Document Summary page on Available fromAmerican National Standards Institute (ANSI), 25 W. 43rd St.,
the ASTM website. 4th Floor, New York, NY 10036, http://www.ansi.org.
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D5243 − 92 (2019)
NOTE1—Thelossofenergyneartheentranceisrelatedtothesuddencontractionandsubsequentexpansionofthelivestreamwithintheculvertbarrel.
FIG. 1 Definition Sketch of Culvert Flow
αV
property applies. For example, A is the area of Section 1.
h 5
v
Items that apply to a reach between two sections are identified 2g
by subscripts indicating both sections. For example, h is the
f
1–2
where:
friction loss between Sections 1 and 2.
α = the velocity-head coefficient,
3.3.4 cross sectional area (A), n—the area occupied by the
V = the mean velocity in the cross section, in ft/s (m/s), and
water.
3.3.5 energy loss (h), n—the loss due to boundary friction
f g = the acceleration due to gravity, in ft/s/s (m/s/s).
between two locations.
3.3.11 wetted perimeter (WP), n—the length along the
3.3.5.1 Discussion—Energy loss is computed as follows:
boundary of a cross section below the water surface.
Q
h 5 L
S D
f
K K 4. Summary of Test Method
1 2
4.1 The determination of discharge at a culvert, either after
where:
3 3
a flood or for selected approach stages, is usually a reliable
Q = the discharge in ft /s (m /s), and
practice. A field survey is made to determine locations and
L = the culvert length in ft (m).
elevationsofhigh-watermarksupstreamanddownstreamfrom
3.3.6 Froude number (F), n—anindextothestateofflowin
theculvert,andtodetermineanapproachcrosssection,andthe
the channel. In a rectangular channel, the flow is subcritical if
culvert geometry. These data are used to compute the eleva-
the Froude number is less than 1.0, and is supercritical if it is
tions of the water surface and selected properties of the
greater than 1.0.
sections. This information is used along with Manning’s n in
3.3.6.1 Discussion—The Froude number is computed as
the Manning equation for uniform flow and discharge coeffi-
follows:
cients for the particular culvert to compute the discharge, Q,in
V
cubic feet (metres) per second.
F 5
=
gd
m
5. Significance and Use
where:
5.1 This test method is particularly useful to determine the
V = the mean velocity in the cross section, ft/s (m/s),
discharge when it cannot be measured directly with some type
d = the average depth in the cross section, in ft (m), and
m
ofcurrentmetertoobtainvelocitiesandsoundingequipmentto
2 2
g = the acceleration due to gravity (32 ft/s ) (9.8 m/s ).
determine the cross section. See Test Method D3858.
3.3.7 high-water marks, n—indications of the highest stage
5.2 Even under the best of conditions, the personnel avail-
reached by water including, but not limited to, debris, stains,
able cannot cover all points of interest during a major flood.
foam lines, and scour marks.
The engineer or technician cannot always obtain reliable
3.3.8 hydraulic radius (R), n—the area of a cross section or
results by direct methods if the stage is rising or falling very
subsection divided by the wetted perimeter of that section or
rapidly,ifflowingiceordebrisinterfereswithdepthorvelocity
subsection.
measurements, or if the cross section of an alluvial channel is
scouring or filling significantly.
3.3.9 roughness coeffıcient (n), n—Manning’s n is used in
the Manning equation.
5.3 Under flood conditions, access roads may be blocked,
3.3.10 velocity head (h ), n—is computed as follows: cableways and bridges may be washed out, and knowledge of
v
D5243 − 92 (2019)
the flood frequently comes too late. Therefore, some type of 9.2 The placement of a roadway fill and culvert in a stream
indirect measurement is necessary. The use of culverts to channel causes an abrupt change in the character of flow. This
determine discharges is a commonly used practice. channel transition results in rapidly varied flow in which
acceleration due to constriction, rather than losses due to
6. Apparatus boundary friction, plays the primary role. The flow in the
approach channel to the culvert is usually tranquil and fairly
6.1 The equipment generally used for a “transit-stadia”
uniform. Within the culvert, however, the flow may be
survey is recommended. An engineer’s transit, a self-leveling
subcritical,critical,orsupercriticaliftheculvertispartlyfilled,
level with azimuth circle, newer equipment using electronic
or the culvert may flow full under pressure.
circuitry, or other advanced surveying instruments may be
9.2.1 The physical features associated with culvert flow are
used.Necessaryequipmentincludesalevelrod,rodlevel,steel
illustrated in Fig. 1. They are the approach channel cross
and metallic tapes, survey stakes, and ample note paper.
section at a distance equivalent to one opening width upstream
6.2 Additional items of equipment that may expedite a
from the entrance; the culvert entrance; the culvert barrel; the
survey are tag lines (small wires with markers fixed at known
culvert outlet; and the tailwater representing the getaway
spacings), vividly colored flagging, axes, shovels, hip boots or
channel.
waders, nails, sounding equipment, ladder, and rope.
9.2.2 The change in the water-surface profile in the ap-
6.3 Acamerashouldbeavailabletotakephotographsofthe
proach channel reflects the effect of acceleration due to
culvert and channel. Photographs should be included with the
contraction of the cross-sectional area. Loss of energy near the
field data.
entrance is related to the sudden contraction and subsequent
expansion of the live stream within the barrel, and entrance
6.4 Safety equipment should include life jackets, first aid
geometry has an important influence on this loss. Loss of
kit, drinking water, and pocket knives.
energy due to barrel friction is usually minor, except in long
rough barrels on mild slopes. The important features that
7. Sampling
controlthestage-dischargerelationattheapproachsectioncan
D1129 is not
7.1 Sampling as defined in Terminology
be the occurrence of critical depth in the culvert, the elevation
applicable in this test method.
of the tailwater, the entrance or barrel geometry, or a combi-
nation of these.
8. Calibration
9.2.3 Determine the discharge through a culvert by applica-
8.1 Checkadjustmentofsurveyinginstruments,transit,etc.,
tion of the continuity equation and the energy equation
daily when in continuous use or after some occurrence that
between the approach section and a control section within the
may have affected the adjustment.
culvert barrel. The location of the control section depends on
the state of flow in the culvert barrel. For example: If critical
8.2 The standard check is the “two-peg” or “double-peg”
flow occurs at the culvert entrance, the entrance is the control
test. If the error is over 0.03 in 100 ft (0.091 m in 30.48 m),
section, and the headwater elevation is not affected by condi-
adjust the instrument. The two-peg test and how to adjust the
tions downstream from the culvert entrance.
instrumentaredescribedinmanysurveyingtextbooks.Referto
manufacturers’ manual for the electronic instruments.
10. General Classification of Flow
8.3 The “reciprocal leveling” technique (1) is considered
the equivalent of the two-peg test between each of two 10.1 Culvert Flow—Culvert flow is classified into six types
successive hubs.
on the basis of the location of the control section and the
relative heights of the headwater and tailwater elevations to
8.4 Visually check sectional and telescoping level rods at
heightofculvert.ThesixtypesofflowareillustratedinFig.2,
frequent intervals to be sure sections are not separated. A
and pertinent characteristics of each type are given in Table 1.
properfitateachjointcanbecheckedbymeasurementsacross
the joint with a steel tape.
10.2 Definition of Heads—The primary classification of
flowdependsontheheightofwaterabovetheupstreaminvert.
8.5 Check all field notes of the transit-stadia survey before
This static head is designated as h − z, where h is the height
proceeding with the computations. 1 1
abovethedownstreaminvertand zisthechangeinelevationof
theculvertinvert.Numericalsubscriptsareusedtoindicatethe
9. Description of Flow at Culverts
section where the head was measured.Asecondary part of the
9.1 Relations between the head of water on and discharge
classification, described in more detail in Section 18, depends
through a culvert have been the subjects of laboratory inves-
onacomparisonoftailwaterelevation h totheheightofwater
tigations by the U.S. Geological Survey, the Bureau of Public
at the control relative to the downstream invert. The height of
Roads,theFederalHighwayAdministration,andmanyuniver-
water at the control section is designated h .
c
sities. The following description is based on these studies and
10.3 General Classifications—From the information in Fig.
field surveys at sites where the discharge was known.
2, the following general classification of types of flow can be
made:
10.3.1 If h /D is equal to or less than 1.0 and (h − z)/D is
The boldface numbers in parentheses refer to a list of references at the end of 4 1
this standard. less than 1.5, only Types 1, 2 and 3 flow are possible.
D5243 − 92 (2019)
FIG. 2 Classification of Culvert Flow
TABLE 1 Characteristics of Flow Types
NOTE 1—D=maximum vertical height of barrel and diameter of circular culverts.
h 2z h h
1 4 4
Location of
Flow Type Barrel Flow Kind of Control Culvert Slope
D h D
c
Terminal Section
1 Partly full Inlet Critical depth Steep <1.5 <1.0 91.0
2 do Outlet do Mild <1.5 <1.0 91.0
3 do do Backwater do <1.5 >1.0 91.0
4 Full do do Any >1.0 . . . >1.0
5 Partly full Inlet Entrance geometry do :1.5 . 91.0
6 Full Outlet Entrance and barrel geometry do :1.5 . 91.0
10.3.2 If h /D and (h − z)/D are both greater than 1.0, only illustratedinFig.3.Thespecificenergy, H ,istheheightofthe
4 1 o
Type 4 flow is possible. energy grade line above the lowest point in the cross section.
10.3.3 If h /D is equal to or less than 1.0 and (h − z)/D is
Thus:
4 1
equal to or greater than 1.5, only Types 5 and 6 flow are
V
possible. H 5 d1
o
2g
10.3.4 If h /D is equal to or greater than 1.0 on a steep
culvert and (h − z)/D is less than 1.0, Types 1 and 3 flows are where:
z
possible. Further identification of the type of flow requires a
H = specific energy,
o
trial-and-error procedure that takes t
...
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