irrigation and hydrology Flashcards
Shrouding is provided in
slotted type tube wells
The efficiency of a pump may be taken as
.65 indiabix
For computing the run off volumes of large areas, number of infiltrations used are
2 infiltrometers are used.
- Single ring Infiltrometer
- Double ring Infiltrometer
If s is the potential infiltration, P is rainfall in cm in a drainage of a soil with fair pasture cover, the direct run off Q in cm is given by
Soil Conservation Services (SCS)-Curve Number(CN) method of estimating Runoff Volume:
Ref: Subramanya book(page number 189) there should be square in the numerator.
Q=(P-0.2S)^2/(P+0.8S) for P>0.2S.
For the estimate of high floods in fan-shaped catchment, the formula used is
Inglis formula
If the potential infiltration of a water shed having a soil with fair pasture cover, is 10 cm and rainfall is 12 cm, the direct run off is
for Direct Run off.
Q = (P-0.2S)^2/(P-0.8S).
Put Value In Equation.
P = 12 and S = 10,
We Will Get Q = 5cm.
[A]. The rate of flow of water through a unit cross-sectional area under a unit hydraulic gradient, is called coefficient of permeability
[B]. The rate of flow of water through a vertical strip of the acquifer of unit width and full depth under a unit hydraulic gradient, is called coefficient of transmissibility
[C]. The flow of water through acquifers, is governed by the Darcy’s law
[D].
The term ‘transmissibility’ was introduced by Meinzer @
[E]. The ratio of coefficient of transmissibility and coefficient of permeability, is equal to the depth of acquifer through which water flows.
Transmissibility was introduced by “theis” (1935).
Precipitation caused by lifting of an air mass due to the pressure difference, is called
cyclonic precipitation
Convective ……….Temperature diffrence.
Cyclonic……………Pressure diffrence.
Frontal ……………Warm and cold air masses.
Orographic……….Mountain barrier.
The standard height of a standard rain gauge, is
30 cm
Pick up the correct statement from the following :
[A]. Central portion of a cyclone acts as a chimney through which air gets lifted
[B]. Cyclonic precipitation caused by a warm front is generally continuous
[C]. Convective precipitation generally occurs in the form of showers of high intensity in short duration
[D]. Greatest amount of orographic precipitation falls in the windward side of the barrier
[E].
All the above. @
Pick up the correct statement from the following :
[A]. Central portion of a cyclone acts as a chimney through which air gets lifted
[B]. Cyclonic precipitation caused by a warm front is generally continuous
[C]. Convective precipitation generally occurs in the form of showers of high intensity in short duration
[D]. Greatest amount of orographic precipitation falls in the windward side of the barrier
[E].
All the above. @
The best instrument for measuring the velocity of a stream flow is
Price’s current meter
The Dupuit formula is based on no of observation well?
no observation well
For high flood estimates the average value of the constant C in Dicken’s formula Q = CA3/4, is
Here, it is 11.5 * A^(3/4).
If h is the loss due to friction in a pipe. Total losses in strainer and bends may be taken as
0.25 h
Dicken’s formula for high flood estimate, is useful only for the catchments in
Northern India
Q = CA^3/4
And Ryves formula is for southern India.
Q = CA^2/3
The air from central portion of cyclone’s gets lifted for causing precipitation
The air from central portion of cyclone’s gets lifted for causing precipitation
The specifications of most commonly used standard gauges in India, are
200 sq. cm collector and 4 litres bottle
Pick up the correct statement from the following :
[A]. Higher the gauge, more deficient will be the rain catch
[B]. Heavier the rain, lesser will be the rain catch
[C]. The trees serving as wind brakes in the vicinity of the gauge, should not subtend angles greater than 45°
[D]. Coniferrous forest is idealy suited for installing the gauge
[E].
All the above.
Pick up the correct statement from the following :
[A]. Higher the gauge, more deficient will be the rain catch
[B]. Heavier the rain, lesser will be the rain catch
[C]. The trees serving as wind brakes in the vicinity of the gauge, should not subtend angles greater than 45°
[D]. Coniferrous forest is idealy suited for installing the gauge
[E].
All the above.
Sharp crested weirs are generally used
for large flows
For efficient working of a control meter, its throat length is approximately kept
three times the critical depth
The form factor of a drainage basin is obtained by dividing
[B]. average width of the basin by the axial basin
[C]. area of the basin by the square of the axial length
both
Yield of a drainage basin is the run off over long periods
Yield of a drainage basin is the run off over long periods
Pick up the correct statement from the following :
[A]. The amount of water retained on the surface of soil grains by molecular attraction, is known as pellicular water
[B]. The degree of resistance to movement of the pellicular water generally expressed by the surface tension
[C]. The pellicular water held in any soil, is called field capacity
[D]. The portion of the pellicular water absorbed by the root action of the vegetation, is called available moisture
[E].
All the above. @
Pick up the correct statement from the following :
[A]. The amount of water retained on the surface of soil grains by molecular attraction, is known as pellicular water
[B]. The degree of resistance to movement of the pellicular water generally expressed by the surface tension
[C]. The pellicular water held in any soil, is called field capacity
[D]. The portion of the pellicular water absorbed by the root action of the vegetation, is called available moisture
[E].
All the above. @
The equation P - Q = Te φindex for determining the infiltration capacity, was suggested by
The equation P - Q = Te φindex for determining the infiltration capacity, was suggested by
[A]. Horton @
The discharge over a trapezoidal crest of a Sarda fall with free over fall conditions, is
[A]. 0.45 2g . LH3/2 (H/B)1/3
[B]. 0.45 2g . LH2/3 (H/B)2/3
[C]. 0.45 2g . LH3/2 (H/B)1/6 @
[D]. 0.45 2g . LH1/6 (H/B)3/2
The formula is same only but, 0.45 is coefficient for discharge(Cd) for the trapezoidal section and 0.415 for the rectangular crest.
A river training work is generally required when the river is
[A]. meandering @
[B]. aggrading
[C]. degrading
[D]. all the above.
A river training work is generally required when the river is
[A]. meandering @
[B]. aggrading
[C]. degrading
[D]. all the above.
Pick up the correct statement from the following:
[A]. If the flexibility is more than one, the outlet is hyper-proportional
[B]. If the setting of an outlet is higher than that required for proportionality, the outlet is hyper-proportional
[C]. If the setting of an outlet is lower than that required for proportionality, the outlet is sub-proportional
[D]. If the flexibility is zero, it is a rigid module
[E].
All the above. @
Pick up the correct statement from the following:
[A]. If the flexibility is more than one, the outlet is hyper-proportional
[B]. If the setting of an outlet is higher than that required for proportionality, the outlet is hyper-proportional
[C]. If the setting of an outlet is lower than that required for proportionality, the outlet is sub-proportional
[D]. If the flexibility is zero, it is a rigid module
[E].
All the above. @
Water-shed line is abondened for aligning an irrigation canal if
[A]. water shed forms a sharp loop [B]. canal has to take off from a river [C]. towns and villages are located on the water shed line [D]. all the above. @
Water-shed line is abondened for aligning an irrigation canal if
[A]. water shed forms a sharp loop
[B]. canal has to take off from a river
[C]. towns and villages are located on the water shed line
[D]. all the above. @
For a given discharge in a channel, Blench curves give the relationship between the loss of head (HL) and
[A]. specific energy up-stream
[B]. specific energy down-stream @
[C]. critical depth of water down-stream
[D]. depth of water down-stream
For a given discharge in a channel, Blench curves give the relationship between the loss of head (HL) and
[A]. specific energy up-stream
[B]. specific energy down-stream @
[C]. critical depth of water down-stream
[D]. depth of water down-stream
If B and d are the bed width and depth of a channel in metres, the combined losses due to evaporation and seepage in cumecs per kilometre length of the channel, is
(1/200) * (B+d)^2/3
Pick up the incorrect statement from the following
[A]. Side walls of a venturi head flume are splayed out from the end of the throat at 1 : 10 for a length of 4.5 m
[B]. Length of side walls should be such that the width of the flume is made equal to 2/3rd the bed width of the distributary
[C]. Once the width of the flume becomes 2/3rd of the width of the distributary, the splayed walls are increased to 1 in 3 to get full bed width
[D].
None of these. @
Pick up the incorrect statement from the following
[A]. Side walls of a venturi head flume are splayed out from the end of the throat at 1 : 10 for a length of 4.5 m
[B]. Length of side walls should be such that the width of the flume is made equal to 2/3rd the bed width of the distributary
[C]. Once the width of the flume becomes 2/3rd of the width of the distributary, the splayed walls are increased to 1 in 3 to get full bed width
[D].
None of these. @