ISO 772:1996/Amd 1:2002
(Amendment)Hydrometric determinations — Vocabulary and symbols — Amendment 1: Additional terms and definitions
Hydrometric determinations — Vocabulary and symbols — Amendment 1: Additional terms and definitions
Déterminations hydrométriques — Vocabulaire et symboles — Amendement 1: Termes et définitions supplémentaires
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Standards Content (Sample)
INTERNATIONAL ISO
STANDARD 772
Fourth edition
1996-04-15
AMENDMENT 1
2002-11-15
Hydrometric determinations — Vocabulary
and symbols
AMENDMENT 1: Additional terms and
definitions
Déterminations hydrométriques — Vocabulaire et symboles
AMENDEMENT 1: Termes et définitions supplémentaires
Reference number
ISO 772:1996/Amd.1:2002(E)
©
ISO 2002
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ISO 772:1996/Amd.1:2002(E)
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ISO 772:1996/Amd.1:2002(E)
Contents Page
Foreword . iv
1 General terms . 1
2 Velocity-area methods. 3
3 Notches, weirs and flumes. 4
4 Dilution methods. 4
5 Instruments and equipment. 7
6 Sediment transport . 9
8 Groundwater. 9
Alphabetical index. 20
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ISO 772:1996/Amd.1:2002(E)
Foreword
ISO (the International Organization for Standardization) is a worldwide federation of national standards bodies (ISO
member bodies). The work of preparing International Standards is normally carried out through ISO technical
committees. Each member body interested in a subject for which a technical committee has been established has
the right to be represented on that committee. International organizations, governmental and non-governmental, in
liaison with ISO, also take part in the work. ISO collaborates closely with the International Electrotechnical
Commission (IEC) on all matters of electrotechnical standardization.
International Standards are drafted in accordance with the rules given in the ISO/IEC Directives, Part 3.
The main task of technical committees is to prepare International Standards. Draft International Standards adopted
by the technical committees are circulated to the member bodies for voting. Publication as an International
Standard requires approval by at least 75 % of the member bodies casting a vote.
Attention is drawn to the possibility that some of the elements of this Amendment may be the subject of patent
rights. ISO shall not be held responsible for identifying any or all such patent rights.
Amendment 1 to ISO 772:1996 was prepared by Technical Committee ISO/TC 113, Hydrometric determinations,
Subcommittee SC 3, Terminology and symbols.
Amendment 1 to ISO 772:1996 gives additional English terms and definitions, used in the field of hydrometric
determinations, to the terms and definitions included in ISO 772:1996.
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ISO 772:1996/Amd.1:2002(E)
Hydrometric determinations — Vocabulary and symbols
AMENDMENT 1: Additional terms and definitions
1 General terms
Page 22, clause 1
At the end of clause 1, General terms, add the following terms and definitions.
1.146
hydrometry
science of the measurement of water including the methods, techniques and instrumentation used
NOTE The adjective is “hydrometric”.
1.147
hydrological cycle
constant movement of water above, on and below the earth’s surface
1.148
hydrogeology
study of subsurface water in its geological context
1.149
hydraulic gradient
change in static head per unit distance in a given direction
1.150
static head
height, relative to an arbitrary reference level, of a column of water that can be supported by the static
pressure at a given point
1.151
creek
〈river〉 small river, often a tributary to a larger river
1.152
creek
〈sea coast〉 recessed inlet on a sea coast or estuary
1.153
hydrograph
relation in graphical, equational or tabular form between time and flow variables such as depth, discharge,
stage and velocity
NOTE Typically, stage and discharge hydrographs are used for open channel flows.
1.154
gradually-varied unsteady flow
generally nonuniform flow in which there are no abrupt changes in depth along the longitudinal axis of a
channel and in which depth, together with discharge and velocity, changes with time
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ISO 772:1996/Amd.1:2002(E)
1.155
live storage
reservoir storage which can be drawn off for users downstream
1.156
total storage
reservoir storage between the lowest bed level and the top water level
1.157
flood storage
volume of water temporarily held above the top water level of a reservoir during a flood event
NOTE Flood storage is not retained in the reservoir but is discharged through an overflow until the normal top water
level is reached.
1.158
boundary condition
condition to be satisfied by a dependent variable of a differential equation along the boundary of a model
domain
NOTE Boundary conditions for the dependent variables are specified at the physical extremities of the modelled region
for the duration of the model application.
1.159
Courant condition
condition for the numerical stability of the explicit formulation of a numerical scheme which requires that the
ratio (C ) of the propagation speed of a physical disturbance to that of a numerical signal should not exceed
r
unity, i.e. C u 1
r
NOTE The condition is a requirement for an explicit-finite difference formulation applied to a hyperbolic partial
differential equation.
1.160
explicit finite-difference numerical scheme
scheme which converts either the characteristic equation or the governing equation into an equation from
which any unknown may be evaluated directly (explicitly) without an iterative computation
NOTE 1 Dependent variables on the advanced time level are determined one point at a time from known values and
conditions at the present or previous time levels.
NOTE 2 The stability of an explicit scheme is conditional upon an error being a function of the time and distance finite-
difference step sizes which may result in an error growing as the solution progresses.
NOTE 3 When the Courant condition is met, resulting in limitations in the maximum time and distance steps which can be
used, generally an explicit scheme is stable, but there can be instances of instability.
NOTE 4 If the converted equation is linear and algebraic, an iterative computation is not needed.
1.161
implicit finite-difference numerical scheme
scheme which converts either the characteristic equation or the governing equation into a nonlinear algebraic
equation from which an unknown may be evaluated iteratively
NOTE 1 All of the unknowns within the model domain are determined simultaneously.
NOTE 2 Generally an implicit scheme is stable.
NOTE 3 Although complex algorithms are required, generally an implicit scheme is computationally sufficient.
1.162
initial condition
description of the discharge, depth of flow or other dynamic condition at the beginning of a simulation period
for unsteady flow models
NOTE For subsequent times, the state of the system is described by the governing equations and the boundary
conditions.
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ISO 772:1996/Amd.1:2002(E)
1.163
method of characteristics
mathematical approach for solving boundary values by transforming the original partial differential equations
representing the physical system into corresponding characteristic equations
NOTE Characteristic equations are ordinary differential equations and, generally, are more amenable to numerical
solution than are the partial differential equations.
1.164
momentum coefficient
Boussinesq coefficient
quantification of the deviation of the velocity at any point in a cross-section from a uniform velocity distribution
in the same cross-section
NOTE Values of the coefficient:
a) unity indicates that a uniform velocity distribution is present in the cross-section;
b) 1,01 to 1,12 indicates a fairly straight prismatic channel;
c) < 1,0 indicates a large or deep channel.
1.165
standing wave
stationary wave
curved symmetrically-shaped wave on the water surface, and on the channel bed, that is virtually stationary
NOTE When standing waves form, the water surface and the bed surfaces are roughly parallel and in phase.
1.166
isotropic
having the same properties in all directions
1.167
photomultiplier
electronic device for amplifying and converting light pulses into measurable electrical signals
2 Velocity-area methods
Page 32, clause 2
At the end of clause 2, Velocity-area methods, add the following terms and definitions.
2.57
large river
river in which measurements are difficult because of its large discharge or its large physical parameters
2.58
flood flow
flow corresponding to or exceeding natural bankfull stage
NOTE It may or may not be confined within banks.
2.59
bankfull stage
stage at which an open watercourse just overflows its natural banks
2.60
rating curve
graphical representation of a stage-discharge relation or rating
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ISO 772:1996/Amd.1:2002(E)
2.61
divergence of tidal conditions
angular deviation in degrees between the flow axis of the ebb current and of the flood current, at a point where
the axes cross
NOTE In a straight ideal reach, there will be no deviation. In most cases, when conditions are not ideal, the ebb and the
flood directions are not on the same axis and there will be an angular deviation.
2.62
mixed tides
tides which have at least two markedly unequal successive high waters, or at least two markedly unequal
successive low waters, or both
2.63
ebb predominance
situation where the ebb flow exceeds the flood flow, over a tidal cycle, at a point or on a vertical
NOTE Usually the extent of the predominance is assessed using integrations of velocity-time graphs.
2.64
flood predominance
situation where the flood flow exceeds the ebb flow, over a tidal cycle, at a point or on the vertical
NOTE 1 Usually the extent of the predominance is assessed using integrations of velocity-time graphs.
NOTE 2 When an integration value is a net zero, there is no predominance.
2.65
sand point
pipe with a well screen, underlying or adjacent to a stream, in which a gas-purge orifice could be installed
3 Notches, weirs and flumes
Page 43, clause 3
At the end of clause 3, Notches, weirs and flumes, add the following term and definition.
3.47
vertical underflow gate
vertical gate situated in a channel of rectangular cross-section with a flat bed for regulating the water level
upstream of the gate or the discharge through the gate opening
NOTE 1 The gate is movable in vertical slots and it can be raised or lowered by hand or mechanically.
NOTE 2 The underflow is two-dimensional except at vertically narrow gate openings.
4 Dilution methods
Page 46, clause 4
Replace the term and definition entry 4.19 with the following:
4.19
becquerel
Bq
curie 〈superseded〉
−1
1 Bq= 1 s
NOTE 1 The becquerel is the special name for second to the power minus one, used as the SI unit of volumetric
10
radioactivity; it has replaced the curie (Ci), where 1 Ci = 3,7 × 10 Bq (exactly).
3 6 9
NOTE 2 The following multiples are used: 1 kBq = 10 Bq; 1 MBq = 10 Bq; 1 GBq = 10 Bq.
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ISO 772:1996/Amd.1:2002(E)
Page 50, clause 4
At the end of clause 4, Dilution methods, add the following terms and definitions.
4.43
radioactive tracer
emitter of gamma rays or beta particles which has properties that mimic the properties of the fluid being traced
cf. radioactive isotope (4.28)
4.44
radiation detector
part of the detection apparatus sensitive to gamma radiation that permits the measurement of activity or of
count rate
NOTE The detector is comprised of a solid scintillation detector which uses the excitation of atoms or molecules by
gamma radiation, and a photomultiplier tube and preamplifier.
4.45
lead castle
lead shield comprising a layer or mass of intervening material designed to attenuate or reduce the strength of
radiation from a radioactive source during transport, or when not in use, and to protect analytical instruments
from background radiation
4.46
radiation detector count rate
N
m
rate of production of electrical pulses in the radiation detector (i.e. the count rate measured by the detector),
which is equal to the sum of the count rate due to the activity of the radioactive tracer together with the
background count rate with no radioactive tracer present, and is given by the expression
NN=+N
m b
where
N is the radioactive count rate;
N is the background count rate
b
NOTE This definition applies only to detectors where a pulse signal is the result of an individual directly or indirectly
ionizing particle passing through the sensitive volume of the detector.
4.47
radioactive decay
A
decrease in activity of a radioelement with time and described by the following expression:
AA=−exp λt
()
0
where
A is the activity at time t;
A is the activity at time t (t = 0);
0 0
λ is the radioactive decay constant, expressed in reciprocal seconds, specific for each radioelement;
t is the time, expressed in seconds
NOTE 1 In terms of the radiation detector count rate (4.46), this expression is given as
NN=−exp λt
( )
0
where N and N are the relevant radioactive count rates determined under identical counting conditions.
0
NOTE 2 The radioactive decay constant is given by the following expression:
λ= 0,693 T
12
where T is the half-life of the radioelement.
1/2
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ISO 772:1996/Amd.1:2002(E)
4.48
dead time of the counting apparatus
t
one of the following whichever is greater:
a) pulse resolving time of the associated electronics; or
b) minimum time from the initial production of a pulse due to radiation and that time the detector is next able
to detect ionizing radiation
NOTE 1 It is related to the radiation detector count rate by the expression
N
m
N =
t 0
1− N t
m
where
N is the radiation detector count rate;
m
t is the dead time of the system;
N would be the count rate if the dead time were zero.
t0
This expression is only true where the total time the system is dead does not approach the real time limit.
NOTE 2 The dead time is not necessarily a constant for a detector, it can vary with the count rate and the type of radiation
being detected.
4.49
radionuclide generator
system, often automatic, which utilizes the property of certain water insoluble radionuclides, in producing a
soluble radionuclide by radioactive decay
NOTE After a certain regeneration time, a dose of usable daughter nuclide is obtained by elution of the mother nuclide.
4.50
conservative tracer concentration
tracer concentration that would occur at a downstream cross-section if the mass of tracer passing the cross-
section were the same as the injected mass
4.51
dispersion of a tracer
process by which differential velocities, turbulent motions and the rate of diffusion of a liquid causes the
spreading of a cloud of dissolved or suspended substances throughout the liquid
NOTE In a stream, generally dispersion takes place vertically in the water columns, transversely across the stream and
longitudinally in the direction of flow.
4.52
dispersion coefficient of a tracer
coefficient used to describe the capacity of a moving liquid to dissipate an initially localized substance or
property throughout the liquid
NOTE In open channel flow, dispersion takes place vertically, transversely and longitudinally. Each component of the
dispersion has its own dispersion coefficient.
4.53
time of trace of a tracer
time for the movement of liquid, or of dissolved materials, between cross-sections in an open channel
NOTE 1 Time of travel may refer to the leading edge, the peak concentration, the mass centroid or the trailing edge of a
dissolved material in a stream.
NOTE 2 When the term is used for the time of travel for any part of the tracer other than the centroid, it should be
qualified.
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ISO 772:1996/Amd.1:2002(E)
4.54
tracer recovery ratio
ratio of the tracer mass recovered in a stream to the tracer mass injected, as determined by sampling
4.55
unit tracer concentration
concentration of a tracer in a stream for one unit of injected conservative tracer in one unit of discharge
5 Instruments and equipment
Page 63, clause 5
At the end of clause 5, Instruments and equipment, add the following terms and definitions.
5.66
permanent flowmeter
flowmeter installed for a long period of time (in excess of about 12 months) and used to determine flow
continuously or at discrete time intervals
NOTE 1 Any high costs incurred in the installation of these flowmeters may be tolerated as they are spread over a period
of time.
NOTE 2 The measurements provided may be used as the basis for an archive system to examine present trends, to
forecast future trends and to determine daily operational requirements.
5.67
temporary flowmeter
flowmeter installed for a specific period of time (no more than about 12 months) and used to determine flow
continuously or at discrete time intervals
NOTE The installation of the flowmeter needs to be simple with minimal or no associated civil engineering costs.
5.68
portable flowmeter
flowmeter, not used as part of a fixed installation, used to obtain instantaneous measurements of flow or the
velocity and depth components thereof
5.69
hydrometric equipment
equipment used for the hydrometric monitoring of hydrological parameters
5.70
recording device
device that records automatically, either continuously or at regular time intervals, the parameters sensed by
any associated sensors
5.71
recording equipment
equipment comprising one or more sensors and a recording device
NOTE 1 The equipment producing a record demonstrating changes of value of a hydrological parameter with time may
require the incorporation of a timing device.
NOTE 2 If the record comprises observations of the changes of the value of a sensed hydrological variable linked to
changes in one or more other physical parameters, the recording equipment should monitor adequately such linkages.
5.72
non-recording equipment
equipment comprising one or more sensors but no recording device
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ISO 772:1996/Amd.1:2002(E)
5.73
instrument carriage
device having one or more track wheels which run on the main cable, a pulley to support the instrument
suspension cable and a point of attachment for the tow cable
5.74
load-activated brake
component of a manual gauging reel which prevents the reel handle from being driven by the load when the
handle is released by the operator
5.75
payout rate
rate at which a traversing cable or a suspension cable is paid out by a gauging reel
5.76
torque limiter
device to limit the transmission of torque by causing the driving element to slip at a pre-determined rate
5.77
tower
pier post
principal support structure for a cableway
5.78
minimum winding diameter
minimum diameter of a drum or a pulley around which a cable may be wound or bent without causing damage
to the cable
5.79
winding handle
handle of a manual gauging reel by which a motive force is applied
5.80
cableway support
structure that supports the main cable span across the stream
NOTE This structure may also provide mountings for the winch and pulleys (sheaves) carrying the tow and suspension
cables.
5.81
personnel carriage
work platform or cabin suspended from track wheels running on the main cable from which gauging
observations are made
5.82
track wheel
sheave (grooved wheel) that rides on the main cable to support the carriage
5.83
tracking window
test interval of limited size which follows, and centres itself automatically at, the depth indicated by the last
received echo
NOTE 1 If the next echo falls within the window, the signal is accepted as correct; if it does not, the signal is rejected.
NOTE 2 The purpose of a tracking window is to screen out erroneous readings caused by reflecting materials in the
water, such as fish and debris.
5.84
ping
series of acoustic pulses, of a given frequency, transmitted by an acoustic Doppler current profiler
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ISO 772:1996/Amd.1:2002(E)
5.85
ensemble
collection of pings
NOTE Because the measurement from a single ping has a relatively high uncertainty, the measurements from more
than one ping are averaged to represent a single measurement.
5.86
transect
single pass across a river, lake or estuary
NOTE 1 A transect may be described as a collection of ensembles.
NOTE 2 One transect may constitute a single measurement of discharge.
6 Sediment transport
Page 71, clause 6
At the end of clause 6, Sediment transport, add the following terms and definitions.
6.57
bed-load transport model
physical or numerical model of hydraulic and sediment variables which can be used to predict the bed-load
transport rates of sediment along the channel bed
6.58
bed-load sampler efficiency
ratio of the quantity of sediment trapped in a bed-load sampler to the quantity of the sediment in the stream
that would be transported as bed load through the width of the flow occupied by the intake of the sampler,
without the sampler in position
6.59
weathering
process of rock breakdown and chemical decomposition instigated by external agencies such as wind, rain,
change in temperature and vegetation
8 Groundwater
Page 80, clause 8
After clause 7, add clause 8, Groundwater, which contains the following terms and definitions.
8.1
absorbed water
water and/or dissolved matter incorporated within the structure of solid, soil or mineral particles
8.2
abstraction
removal of water from a borehole or well
8.3
access tube
dip tube
pipe inserted into a well to permit safe installation of instruments, thus safeguarding them from touching or
becoming entangled with the pump or other equipment in the well
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ISO 772:1996/Amd.1:2002(E)
8.4
adhesive water
water forming a film around soil particles, over absorbed water, and held by forces of molecular attraction after
gravity water has drained, but having less strength than adsorption water and without perceptible emission of
heat
NOTE Adsorbed water is entirely fixed, whereas adhesive or pellicular water may move from one particle to another.
8.5
adsorbed water
water held on the surface of individual soil particles by the forces of molecular attraction with emission of heat
(heat of wetting)
8.6
air lifting
method of producing a discharge of water from a borehole by the injection of compressed air
8.7
API unit
unit or counting rate used for scaling gamma-ray logs and neutron logs
NOTE API is the abbreviation for the American Petroleum Institute.
8.8
apparent velocity of groundwater
apparent distance covered per unit time by groundwater in the saturated zone
NOTE It is defined as the product of the coefficient of permeability and hydraulic gradient, divided by the porosity of the
porous medium through which the ground water is moving.
8.9
aquiclude
formation or group of formations which, although porous and capable of absorbing water slowly, will not
transmit water rapidly enough to furnish a sufficient supply for a well or spring even under saturated conditions
8.10
aquifer
lithological unit, group of lithological units, or part of a lithological unit containing sufficient saturated permeable
material to yield significant quantities of water to wells, boreholes, or springs
8.11
aquifer loss
head loss at a pumped or overflowing well associated with groundwater flow through the aquifer to the well
face
8.12
aquifer properties
properties of an aquifer that determine its hydraulic behaviour and its response to abstraction
8.13
aquifuge
impermeable formation which has no interconnected openings and hence cannot absorb or transmit water
8.14
aquitard
saturated but poorly permeable stratum that impedes groundwater movement and does not yield water to
wells, but that may transmit appreciable water to and from adjacent aquifers
8.15
argillaceous
containing clay minerals
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ISO 772:1996/Amd.1:2002(E)
8.16
artificial recharge
augmentation of the natural infiltration of precipitation, or surface water, into underground formation by some
method of construction, spreading of water, or by artificially changing natural conditions
8.17
bed resolution
minimum bed thickness that can be resolved
8.18
bonding
seal between a borehole lining and the geological formation
8.19
borehole
hole, usually vertical, bored to determine ground conditions, for extraction of water or measurement of
groundwater level
8.20
cable boom
rigid support from which the geophysical sonde and cable are suspended
8.21
calibration tail
section of field log carrying information on sonde calibration
8.22
casing
tubular retaining structure, which is installed in a drilled borehole or excavated well, to maintain the borehole
opening
NOTE Plain casing prevents the entry of water (see also 8.70 and 8.71).
8.23
casing string
set of lengths of casing assembled for lowering into a borehole
8.24
coefficient of permeability
rate of flow of a fluid through a unit cross-section of a porous mass under a unit hydraulic gradient at a
specified temperature
8.25
column pipe
part of the rising main within the well
8.26
composite log
several well logs of the same or similar types, suitable for correlation, spliced together to form a single
continuous record
8.27
cone of depression
portion of the potentiometric surface that is perceptibly lowered as a result of abstraction of groundwater from
a well
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ISO 772:1996/Amd.1:2002(E)
8.28
confined groundwater
body of groundwater overlain by material sufficiently impermeable to inhibit free hydraulic connection with
overlying groundwater, except at the intake
NOTE Confined groundwater moves under the pressure due to difference in head between intake and discharge areas
of the confined water body and is under sufficient pressure to rise above the bottom of the upper confining bed, if given a
...
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