ASTM D5243-92(2013)

NOTICE: This standard has either been superseded and replaced by a new version or withdrawn.
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Designation:D5243 −92 (Reapproved 2013)
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 748 Liquid 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—For definitions of terms used in this test
by using a computer program, for a gauge located at the
method, refer to Terminology D1129.
approach section to a culvert.
3.2 Several of the following terms are illustrated in Fig. 1.
1.3 The values stated in inch-pound units are to be regarded
3.3 Definitions of Terms Specific to This Standard:
as the standard. The SI units given in parentheses are for
3.3.1 alpha (α)—a velocity-head coefficient that adjusts the
information only.
velocity head computed on basis of the mean velocity to the
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-
3.3.2 conveyance(K)—ameasureofthecarryingcapacityof
priate safety, health, and environmental practices and deter-
mine the applicability of regulatory limitations prior to use. a channel and having dimensions of cubic feet per second.
3.3.2.1 Discussion—Conveyance is computed as follows:
1.5 This international standard was developed in accor-
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
R = the hydraulic radius, in ft (m).
2. Referenced Documents
3.3.3 cross sections (numbered consecutively in down-
2.1 ASTM Standards:
stream order):
D1129Terminology Relating to Water
3.3.3.1 The approach section, Section 1, is located one
culvert width upstream from the culvert entrance.
3.3.3.2 Cross Sections 2 and 3 are located at the culvert
This test method is under the jurisdiction of ASTM Committee D19 on
entrance and the culvert outlet, respectively.
Waterand is the direct responsibility of Subcommittee D19.07 on Sediments,
Geomorphology, and Open-Channel Flow. 3.3.3.3 Subscripts are used with symbols that represent
Current edition approved Jan. 1, 2013. Published January 2013. Originally
cross sectional properties to indicate the section to which the
approved in 1992. Last previous edition approved in 2007 as D5243–92 (2007).
property applies. For example, A is the area of Section 1.
DOI: 10.1520/D5243-92R13.
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 (2013)
NOTE1—Thelossofenergyneartheentranceisrelatedtothesuddencontractionandsubsequentexpansionofthelivestreamwithintheculvertbarrel.
FIG. 1 Definition Sketch of Culvert Flow
Items that apply to a reach between two sections are identified αV
h 5
v
2g
by subscripts indicating both sections. For example, h is the
f
1–2
friction loss between Sections 1 and 2.
where:
3.3.4 cross sectional area (A)—the area occupied by the
α = the velocity-head coefficient,
water.
V = themeanvelocityinthecrosssection,inft/s(m/s),and
3.3.5 energy loss (h)—the loss due to boundary friction
f
between two locations.
g = the acceleration due to gravity, in ft/s/s (m/s/s).
3.3.5.1 Discussion—Energy loss is computed as follows:
3.3.11 wetted perimeter (WP)—thelengthalongthebound-
Q
ary of a cross section below the water surface.
h 5 L
S D
f
K K
1 2
where: 4. Summary of Test Method
3 3
Q = the discharge in ft /s (m /s), and
4.1 The determination of discharge at a culvert, either after
L = the culvert length in ft (m).
a flood or for selected approach stages, is usually a reliable
3.3.6 Froude number (F)—an index to the state of flow in
practice. A field survey is made to determine locations and
the channel. In a rectangular channel, the flow is subcritical if
elevationsofhigh-watermarksupstreamanddownstreamfrom
the Froude number is less than 1.0, and is supercritical if it is
theculvert,andtodetermineanapproachcrosssection,andthe
greater than 1.0.
culvert geometry. These data are used to compute the eleva-
3.3.6.1 Discussion—The Froude number is computed as
tions of the water surface and selected properties of the
follows:
sections. This information is used along with Manning’s n in
the Manning equation for uniform flow and discharge coeffi-
V
F 5
cients for the particular culvert to compute the discharge, Q,in
=
gd
m
cubic feet (metres) per second.
where:
5. Significance and Use
V = the mean velocity in the cross section, ft/s (m/s),
d = the average depth in the cross section, in ft (m), and
m
5.1 This test method is particularly useful to determine the
2 2
g = the acceleration due to gravity (32 ft/s ) (9.8 m/s ).
discharge when it cannot be measured directly with some type
3.3.7 high-water marks—indications of the highest stage
ofcurrentmetertoobtainvelocitiesandsoundingequipmentto
reached by water including, but not limited to, debris, stains,
determine the cross section. See Practice D3858.
foam lines, and scour marks.
5.2 Even under the best of conditions, the personnel avail-
3.3.8 hydraulic radius (R)—the area of a cross section or
able cannot cover all points of interest during a major flood.
subsection divided by the wetted perimeter of that section or
The engineer or technician cannot always obtain reliable
subsection.
results by direct methods if the stage is rising or falling very
3.3.9 roughness coeffıcient (n)—Manning’s n is used in the
rapidly,ifflowingiceordebrisinterfereswithdepthorvelocity
Manning equation.
measurements, or if the cross section of an alluvial channel is
3.3.10 velocity head (h )—is computed as follows: scouring or filling significantly.
v
D5243−92 (2013)
5.3 Under flood conditions, access roads may be blocked, 9.2 The placement of a roadway fill and culvert in a stream
cableways and bridges may be washed out, and knowledge of channel causes an abrupt change in the character of flow. This
the flood frequently comes too late. Therefore, some type of channel transition results in rapidly varied flow in which
indirect measurement is necessary. The use of culverts to acceleration due to constriction, rather than losses due to
determine discharges is a commonly used practice. boundary friction, plays the primary role. The flow in the
approach channel to the culvert is usually tranquil and fairly
6. Apparatus
uniform. Within the culvert, however, the flow may be
6.1 The equipment generally used for a “transit-stadia” subcritical,critical,orsupercriticaliftheculvertispartlyfilled,
or the culvert may flow full under pressure.
survey is recommended. An engineer’s transit, a self-leveling
level with azimuth circle, newer equipment using electronic
9.2.1 The physical features associated with culvert flow are
circuitry, or other advanced surveying instruments may be illustrated in Fig. 1. They are the approach channel cross
used.Necessaryequipmentincludesalevelrod,rodlevel,steel
section at a distance equivalent to one opening width upstream
and metallic tapes, survey stakes, and ample note paper. from the entrance; the culvert entrance; the culvert barrel; the
culvert outlet; and the tailwater representing the getaway
6.2 Additional items of equipment that may expedite a
channel.
survey are tag lines (small wires with markers fixed at known
9.2.2 The change in the water-surface profile in the ap-
spacings), vividly colored flagging, axes, shovels, hip boots or
proach channel reflects the effect of acceleration due to
waders, nails, sounding equipment, ladder, and rope.
contraction of the cross-sectional area. Loss of energy near the
6.3 Acamerashouldbeavailabletotakephotographsofthe
entrance is related to the sudden contraction and subsequent
culvert and channel. Photographs should be included with the
expansion of the live stream within the barrel, and entrance
field data.
geometry has an important influence on this loss. Loss of
6.4 Safety equipment should include life jackets, first aid
energy due to barrel friction is usually minor, except in long
kit, drinking water, and pocket knives.
rough barrels on mild slopes. The important features that
controlthestage-dischargerelationattheapproachsectioncan
7. Sampling
be the occurrence of critical depth in the culvert, the elevation
7.1 Sampling as defined in Terminology D1129 is not
of the tailwater, the entrance or barrel geometry, or a combi-
applicable in this test method.
nation of these.
9.2.3 Determine the discharge through a culvert by applica-
8. Calibration
tion of the continuity equation and the energy equation
8.1 Checkadjustmentofsurveyinginstruments,transit,etc.,
between the approach section and a control section within the
daily when in continuous use or after some occurrence that
culvert barrel. The location of the control section depends on
may have affected the adjustment.
the state of flow in the culvert barrel. For example: If critical
flow occurs at the culvert entrance, the entrance is the control
8.2 The standard check is the “two-peg” or “double-peg”
section, and the headwater elevation is not affected by condi-
test. If the error is over 0.03 in 100 ft (0.091 m in 30.48 m),
tions downstream from the culvert entrance.
adjust the instrument. The two-peg test and how to adjust the
instrumentaredescribedinmanysurveyingtextbooks.Referto
10. General Classification of Flow
manufacturers’ manual for the electronic instruments.
10.1 Culvert Flow—Culvert flow is classified into six types
8.3 The “reciprocal leveling” technique (1) is considered
on the basis of the location of the control section and the
the equivalent of the two-peg test between each of two
relative heights of the headwater and tailwater elevations to
successive hubs.
heightofculvert.ThesixtypesofflowareillustratedinFig.2,
8.4 Visually check sectional and telescoping level rods at
and pertinent characteristics of each type are given in Table 1.
frequent intervals to be sure sections are not separated. A
properfitateachjointcanbecheckedbymeasurementsacross 10.2 Definition of Heads—The primary classification of
the joint with a steel tape. flowdependsontheheightofwaterabovetheupstreaminvert.
This static head is designated as h − z, where h is the height
1 1
8.5 Check all field notes of the transit-stadia survey before
abovethedownstreaminvertand zisthechangeinelevationof
proceeding with the computations.
theculvertinvert.Numericalsubscriptsareusedtoindicatethe
section where the head was measured.Asecondary part of the
9. Description of Flow at Culverts
classification, described in more detail in Section 18, depends
9.1 Relations between the head of water on and discharge
onacomparisonoftailwaterelevation h totheheightofwater
through a culvert have been the subjects of laboratory inves-
at the control relative to the downstream invert. The height of
tigations by the U.S. Geological Survey, the Bureau of Public
water at the control section is designated h .
c
Roads,theFederalHighwayAdministration,andmanyuniver-
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
the text. less than 1.5, only Types 1, 2 and 3 flow are possible.
D5243−92 (2013)
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 2 z h
1 4
Location of
h
Flow Type Barrel Flow Kind of Control Culvert Slope 4
D h
Terminal Section c
D
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 V
4 1
H 5 d1
o
2g
Type 4 flow is possible.
10.3.3 If h /D is equal to or less than 1.0 and ( h − z)/D is
4 1
where:
equal to or greater than 1.5, only Types 5 and 6 flow are
H = specific energy,
o
possible.
d = maximum depth in the section, in ft,
10.3.4 If h /D is equal to or greater than 1.0 on a steep
V = mean velocity in the section, in ft/s, and
culvert and (h − z)/D is less than 1.0, Types 1 and 3 flows are
2 2
z
g = acceleration of gravity (32 ft/s ) (9.8 m/s ).
possible. Further identification of the type of flow requires a
trial-and-error procedure that takes time and is one of the
11.2 Relation Between Discharge and Depth—It can be
reasons use of the computer program is recommended.
shown that at the point of minimum specific energy, that is, at
critical depth, d , there is a unique relation between discharge
c
11. Critical
...