Streamflow Measurement Flashcards
Objective Questions
The science and practice of water flow measurement is known as
hydrometry
The following is not a direct stream flow determination technique:
Slope-area method
A stilling well is required when the stage measurement is made by employing a
float gauge recorder
In the moving-boat method of stream-flow measurement, the essential measurements
are
the velocity and direction of the current meter, the depths and the time interval
between depth readings
Which of the following instruments is not connected with stream flow measurement?
Hygrometer
The surface velocity at any vertical section of a stream is
larger than the mean velocity in that vertical section
If a gauging section is having shifting control due to backwater effects then
a secondary gauge downstream of the section is needed
The stage discharge relation in a river during the passage of a flood wave is measured.
If QR = discharge at a stage when the water surface was rising and QF = discharge at
the same stage when the water surface was falling then
QR > QF
The dilution method of stream gauging is ideally suited for measuring discharges in
steady flow in a small turbulent stream
The slope-area method is extensively used in
estimation of flood discharge based on high-water marks
For a given stream, the rating curve applicable to a section is available. To determine
the discharge in this stream, the following-data are needed
Stage at the section
During a flood in a wide rectangular channel, it is found that at a section the depth of
flow increases by 50% and at this depth the water-surface slope is half its original value
in a given interval of time. This marks an approximate change in the discharge of
+39%
In a river, the discharge was 173 m3/s, the water surface slope was 1 in 6000 and the
stage at the station X was 10.00 m. If during a flood, the stage at station X was 10.00
and the water surface slope was 1/2000, the flood discharge was approximately
300 m3/s
During a flood, the water surface at a section was found to decrease at a rate of 10 cm/h.
The slope of the river is 1/3600. Assuming the velocity of the flood wave as 2 m/s, the
actual discharge in the stream can be estimated as
2.5% smaller than the normal discharge
Representing the runoff
phase of the hydrologic cycle is the
most important basic data for hydrologic
studies.
Streamflow
