The peak of a 4 hour flood hydrograph is 240 m3/sec . If the rainfall excess is 80 mm and base flow which is constant is 40 m3/sec, then the peak of 4-hours unit hydrograph will be__________________?

Related Mcqs:

1. The unit hydrograph due to a storm may be obtained by dividing the ordinates of the direct runoff hydrograph by_______________?

   A. direct runoff volume
   B. period of storm
   C. total rainfall
   D. none of the above

2. S-hydrograph is used to obtain unit hydrograph of________________?

   A. shorter duration from longer duration
   B. longer duration from shorter duration
   C. both (A) and (B)
   D. none of the above

3. The unit hydrograph of a specified duration can be used to evaluate the hydrograph of storms of_________________?

   A. same duration only
   B. same and shorter duration
   C. same and longer duration
   D. any duration

4. Instantaneous unit hydrograph is a hydrograph of________________?

   1) unit duration
   2) unit rainfall excess
   3) infinitely small duration
   4) infinitely small rainfall excess
   The correct answer is?

   A. (1) and (2)
   B. (1)and(4)
   C. (2) and (3)
   D. (3) and (4)

5. A 6 hours storm had 4 cm of rainfall and the resulting runoff was 2 cm. If <j) index remains at the same value, the runoff due to 10 cm of rainfall in 12 hours in the catchment is___________________?

   A. 4.5 cm
   B. 6.0 cm
   C. 7.5 cm
   D. 9.0 cm

6. The maximum rainfall depth of 300 mm in 24 hours has a return period of 100 years. The probability of 24 hours rainfall equal to or greater than 300 mm occurring at least once in 10 years is given by_____________?

   A. (0.99)10
   B. 1 – (0.99)10
   C. (0.9)’00
   D. l-(0.9)100

7. Assertion A : To estimate the rainfall over a catchment, the number of raingauges required per unit area is large for hilly areas. Reason R : Rainfall gradient is steep. Select your correct answer according to the coding system given below ?

   A. Both A and R are true and R is the correct explanation of A
   B. Both A and R are true but R is not the correct explanation of A
   C. A is true but R is false
   D. A is false but R is true

8. The best unit duration of storm for a unit hydrograph is________________?

   A. 1 hour
   B. one-fourth of basin lag
   C. one-half of basin lag
   D. equal to basin lag

9. For a catchment area of 120 km2, the equilibrium discharge in m3/hour of an S-curve obtained by the summation of 6 hour unit hydro graph is_______________?

   A. 0.2 x 106
   B. 0.6 x 106
   C. 2.4 xlO6
   D. 7.2 xlO6

10. If the risk of a flood occurring in the next 10 years is accepted to 10%, then the return period for design should be__________________?

    A. 1 + (0.9)010
    B. 1 – (0.9)°l0
    C. 1/(1-0.9°10)
    D. 1/(1+ 0.9010)