MCQs of Hyetograph and Hydrograph analysis

Showing 1 to 10 out of 19 Questions
1.

The ordinate of the IUH (Instantaneous Unit Hydrograph) of a catchment at any time t, is

 (a) the slope of the 1 hour unit hydrograph at that time (b) the slope of the direct run off unit hydrograph at that time (c) the slope of the S-curve with effective rainfall intensity of 1 cm/hr (d) difference in the slope of the S-curve and 1 hour unit hydrograph
2.

A peak of a flood hydrograph due to a 6 hour storm is 470 m3/sec. The average depth of rainfall is 8.0 cms. Assume an infiltration loss of 0.25cm/hour and a constant base flow of 15 m3/sec. The peak discharge of 6 hour unit hydrograph for this catchment will be
______________ m3/sec.

 (a) 70 (b) 85 (c) 80 (d) none of these
3.

A basin has an area of 26560 km2, perimeter 965 km and length of thalweg 230 km. The compactness coefficient of the basin is __________.

 (a) 1.67 (b) 0.598 (c) 0.6 (d) 0.33
4.

Fern leaf catchments, when compared with fan shaped catchments, will have

 (a) longer streams. (b) shorter streams. (c) almost equally long streams. (d) longer or shorter streams, depending upon the particular catchment.
5.

A catchment area is in the form of a sector of a circle of radius 3 km and angle 30°. Its hydrograph can be approximated to a triangle having time base = 12 hr. The effective rainfall during the storm of 6hr duration is 3 cm. The peak of this hydrograph will be ____________ m3/s.

 (a) 3.27 (b) 4 (c) 3 (d) 2
6.

During a 3 hour storm event, it was observed that all abstractions other than infiltration are negligible. The rainfall was idealized as three one hour storms of intensity 10 mm/hr, 20 mm/hr and 10 mm/hr respectively and the infiltration was idealized as Horton's curve, φ = 6.8 + 8.7 e–t. [φ in mm/hr and t in hr] The effecitve rainfall is ______________ mm.

 (a) 16.08 (b) 13.63 (c) 12 (d) none of above
7.

For a catchment, the Scurve (or Shydrograph) due to a rainfall of intensity 1 cm/hr is given by Q = 1 – (1 + t ) e–t (t in hr and Q in m3/s). The ordinate of a 2hour unit hydrograph for this catchment at t = 3 hour, will be ___________ m3/s.

 (a) 0.16 (b) 0.27 (c) 0.6 (d) 0.8
8.

The peak flow of a flood hydrograph caused by isolated storm was observed to be 120 m3/s. The storm was of 6 hours duration and had a total rainfall of 7.5 cm. If the base flow and φindex are assumed to be 30 m3/s and 0.25 cm/h respectively, the peak ordinate of the 6h unit hydrograph (in m3/s) of the catchment is

 (a) 12 (b) 15 (c) 16 (d) 20
9.

The 6h unit hydrograph of a catchment is triangular in shape with a base width of 64 hours and peak ordinate of 20 m3/s. If a 0.5 cm rainfall excess occurs in 6 hours in that catchment, the resulting surface runoff hydrograph will have a peak of ____________ m3/s.

 (a) 10 (b) 15 (c) 25 (d) 5
10.

The equilibrium discharge (in cumecs) of the Scurve derived from a 4h unit hydrograph for this catchment, having an area of 360 km2, is __________ m3/s.

 (a) 250.2 (b) 234.5 (c) 263.6 (d) 223.6
Showing 1 to 10 out of 19 Questions