ASTM D5243-92(2007)

NOTICE: This standard has either been superseded and replaced by a new version or withdrawn.
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Designation:D5243 −92(Reapproved2007)
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 2.2 ISO Standards:
ISO 748 Liquid Flow Measurements in Open Channels-
1.1 This test method covers the computation of discharge
Velocity-Area Methods
(the volume rate of flow) of water in open channels or streams
ISO 1070Liquid Flow Measurements in Open Channels-
using culverts as metering devices. In general, this test method
Slope-Area Methods
does not apply to culverts with drop inlets, and applies only to
a limited degree to culverts with tapered inlets. Information
3. Terminology
related to this test method can be found in ISO 748 and ISO
3.1 Definitions—For definitions of terms used in this test
1070.
method, refer to Terminology D1129.
1.2 This test method produces the discharge for a flood
3.2 Several of the following terms are illustrated in Fig. 1.
event if high-water marks are used. However, a complete
3.3 Definitions of Terms Specific to This Standard:
stage-discharge relation may be obtained, either manually or
3.3.1 alpha (α)—a velocity-head coefficient that adjusts the
by using a computer program, for a gauge located at the
velocity head computed on basis of the mean velocity to the
approach section to a culvert.
truevelocityhead.Itisassumedequalto1.0ifthecrosssection
1.3 Thevaluesstatedininch-poundunitsaretoberegarded
is not subdivided.
as the standard. The SI units given in parentheses are for
3.3.2 conveyance(K)—ameasureofthecarryingcapacityof
information only.
a channel and having dimensions of cubic feet per second.
1.4 This standard does not purport to address all of the
3.3.2.1 Discussion—Conveyance is computed as follows:
safety concerns, if any, associated with its use. It is the
1.486
responsibility of the user of this standard to establish appro-
2/3
K 5 R A
n
priate safety and health practices and determine the applica-
bility of regulatory limitations prior to use.
where:
n = the Manning roughness coefficient,
2. Referenced Documents
2 2
A = the cross section area, in ft (m ), and
2.1 ASTM Standards:
R = the hydraulic radius, in ft (m).
D1129Terminology Relating to Water
3.3.3 cross sections (numbered consecutively in down-
D2777Practice for Determination of Precision and Bias of
stream order):
Applicable Test Methods of Committee D19 on Water
3.3.3.1 The approach section, Section 1, is located one
D3858Test Method for Open-Channel Flow Measurement
culvert width upstream from the culvert entrance.
of Water by Velocity-Area Method
3.3.3.2 Cross Sections 2 and 3 are located at the culvert
entrance and the culvert outlet, respectively.
3.3.3.3 Subscripts are used with symbols that represent
This test method is under the jurisdiction of ASTM Committee D19 on
cross sectional properties to indicate the section to which the
Waterand is the direct responsibility of Subcommittee D19.07 on Sediments,
property applies. For example, A is the area of Section 1.
Geomorphology, and Open-Channel Flow.
Items that apply to a reach between two sections are identified
Current edition approved June 15, 2007. Published July 2007. Originally
approved in 1992. Last previous edition approved in 2001 as D5243–92 (2001).
by subscripts indicating both sections. For example, h is the
f
1–2
DOI: 10.1520/D5243-92R07.
friction loss between Sections 1 and 2.
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(2007)
NOTE1—Thelossofenergyneartheentranceisrelatedtothesuddencontractionandsubsequentexpansionofthelivestreamwithintheculvertbarrel.
FIG. 1 Definition Sketch of Culvert Flow
3.3.4 cross sectional area (A)—the area occupied by the where:
water.
α = the velocity-head coefficient,
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
h 5 L
S D ary of a cross section below the water surface.
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
practice. A field survey is made to determine locations and
3.3.6 Froude number (F)—an index to the state of flow in
elevationsofhigh-watermarksupstreamanddownstreamfrom
the channel. In a rectangular channel, the flow is subcritical if
theculvert,andtodetermineanapproachcrosssection,andthe
the Froude number is less than 1.0, and is supercritical if it is
culvert geometry. These data are used to compute the eleva-
greater than 1.0.
tions of the water surface and selected properties of the
3.3.6.1 Discussion—The Froude number is computed as
sections. This information is used along with Manning’s n in
follows:
the Manning equation for uniform flow and discharge coeffi-
V
cients for the particular culvert to compute the discharge, Q,in
F 5
= gd
m
cubic feet (metres) per second.
where:
5. Significance and Use
V = the mean velocity in the cross section, ft/s (m/s),
5.1 This test method is particularly useful to determine the
d = the average depth in the cross section, in ft (m), and
m
2 2
discharge when it cannot be measured directly with some type
g = the acceleration due to gravity (32 ft/s ) (9.8 m/s ).
ofcurrentmetertoobtainvelocitiesandsoundingequipmentto
3.3.7 high-water marks—indications of the highest stage
determine the cross section. See Practice D3858.
reached by water including, but not limited to, debris, stains,
foam lines, and scour marks. 5.2 Even under the best of conditions, the personnel avail-
able cannot cover all points of interest during a major flood.
3.3.8 hydraulic radius (R)—the area of a cross section or
The engineer or technician cannot always obtain reliable
subsection divided by the wetted perimeter of that section or
results by direct methods if the stage is rising or falling very
subsection.
rapidly,ifflowingiceordebrisinterfereswithdepthorvelocity
3.3.9 roughness coeffıcient (n)—Manning’s n is used in the
measurements, or if the cross section of an alluvial channel is
Manning equation.
scouring or filling significantly.
3.3.10 velocity head (h )—is computed as follows:
v
5.3 Under flood conditions, access roads may be blocked,
αV cableways and bridges may be washed out, and knowledge of
h 5
v
2g the flood frequently comes too late. Therefore, some type of
D5243−92(2007)
indirect measurement is necessary. The use of culverts to channel transition results in rapidly varied flow in which
determine discharges is a commonly used practice. acceleration due to constriction, rather than losses due to
boundary friction, plays the primary role. The flow in the
6. Apparatus
approach channel to the culvert is usually tranquil and fairly
uniform. Within the culvert, however, the flow may be
6.1 The equipment generally used for a “transit-stadia”
subcritical,critical,orsupercriticaliftheculvertispartlyfilled,
survey is recommended. An engineer’s transit, a self-leveling
or the culvert may flow full under pressure.
level with azimuth circle, newer equipment using electronic
circuitry, or other advanced surveying instruments may be 9.2.1 The physical features associated with culvert flow are
illustrated in Fig. 1. They are the approach channel cross
used.Necessaryequipmentincludesalevelrod,rodlevel,steel
and metallic tapes, survey stakes, and ample note paper. section at a distance equivalent to one opening width upstream
from the entrance; the culvert entrance; the culvert barrel; the
6.2 Additional items of equipment that may expedite a
culvert outlet; and the tailwater representing the getaway
survey are tag lines (small wires with markers fixed at known
channel.
spacings), vividly colored flagging, axes, shovels, hip boots or
9.2.2 The change in the water-surface profile in the ap-
waders, nails, sounding equipment, ladder, and rope.
proach channel reflects the effect of acceleration due to
6.3 Acamerashouldbeavailabletotakephotographsofthe
contraction of the cross-sectional area. Loss of energy near the
culvert and channel. Photographs should be included with the
entrance is related to the sudden contraction and subsequent
field data.
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
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.
8. Calibration
9.2.3 Determine the discharge through a culvert by applica-
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
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
10.1 Culvert Flow—Culvertflowisclassifiedintosixtypes
the equivalent of the two-peg test between each of two
on the basis of the location of the control section and the
successive hubs.
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
10.2 Definition of Heads—The primary classification of
the joint with a steel tape.
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
1 1
proceeding with the computations.
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
9.2 The placement of a roadway fill and culvert in a stream
made:
channel causes an abrupt change in the character of flow. This
10.3.1 If h /D is equal to or less than 1.0 and ( h − z)/D is
4 1
less than 1.5, only Types 1, 2 and 3 flow are possible.
10.3.2 If h /D and (h − z)/D are both greater than 1.0, only
The boldface numbers in parentheses refer to a list of references at the end of 4 1
the text. Type 4 flow is possible.
D5243−92(2007)
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
D h
c
Terminal Section
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
10.3.3 If h /D is equal to or less than 1.0 and ( h − z)/D is illustratedinFig.3.Thespecificenergy, H ,istheheightofthe
4 1 o
equal to or greater than 1.5, only Types 5 and 6 flow are energy grade line above the lowest point in the cross section.
possible. Thus:
10.3.4 If h /D is equal to or greater than 1.0 on a steep
V
H 5 d1
culvert and (h − z)/D is less than 1.0, Types 1 and 3 flows are
o
z
2g
possible. Further identification of the type of flow requires a
where:
trial-and-error procedure that takes time and is one of the
reasons use of the computer program is recommended. H = specific energy,
o
d = maximum depth in the section, in ft,
11. Critical Depth
V = mean velocity in the section, in ft/s, and
2 2
g = acceleration of gravity (32 ft/s ) (9.8 m/s ).
11.1 Specific Energy—In Type 1 flow, critical depth occurs
attheculvertinlet,andinType2flowcriticalflowoccursatthe 11.2 Relation Between Discharge and Depth—It can be
culvert outlet. Critical depth, d , is the depth of water at the shown that at the point of minimum specific energy, that is, at
c
point of minimum specific energy for a given discharge and critical depth, d , there is a unique relation between discharg
...