The Hydrograph Tutorial 2

15.S-curve is drawn only if the duration of hydrographs is odd number

1.True

2.False

16.The ordinate of S-curve can be drawn by summing the ordinates of unit hydrographs of different storms of different duration but at the same time.

1.True

2.False

17.Average intensity of ER producing the S-curve is equal to 1/D cm/h

1.True

2.False

18.Maximum rate at which an ER of intensity 1/D cm/h can produce a runoff of Q is 2.778*(A/D) m3/s

1.True

2.False

19.If discharge of two S curves (which is derived from A and B hydrographs) is Sa and Sb respectively then ordinates of ER due to 1 cm rainfall and duration T-hr will be :

(Sa-Sb)/(T/D)

1.True

2.False

20.To represent a relationship between ER and DRH,area of catchment must be within 200 ha and 5000 SqKm

1.True

2.False

21.Unit hydrographs can only represent the pattern of runoff due to a rainfall(not for snowfall)

1.True

2.False

22.Accuracy percentage of the time base and peak flow of the estimated unit hydrograph must lies within +-20 and +-10%.

1.True

2.False

23.The duration of DRH for drawing unit hydrograph from a sample of hydrograph must be either equal to rising time,basin lag and time of concentration,whichever is smallest.

1.True

2.False

24.Ideal values of duration will be 1/4 of basin lag and catchment area/1000.

1.True

2.False

25.In prediction of an unit graph from two DRH of different duration method of Superposition or S-Curve is used.

1.True

2.False