Q2/ The ordinates of a 3-hour UH are given in the following table: Time (hour) 3 9. 12 15 18 21 24 27 30 10 30 80 60 50 40 30 10 hour UH (m'/s) (a) Estimate the area of the basin. (b) Determine the DRH ordinates due to two ER of 2 cm and 3 cm occurring in two successive 3-hour durations each. (c) Estimate the flood hydrograph ordinates if the base flow at time 0 h is 10 m²/s and increase to reach 2 m'/s at time of 30h. (d) Estimate the total runoff volume

Q.6.

Figure 2.2 shows a catchment with seven rain guage stations inside it and three stations outside. The rainfall recorded by each of these stations are indicated by the figure. Draw the figure to an enlarged scale and calculate the mean precipitation method by (a) Isohyetal method and by (b) Arithmetic-mean method.

Problem 3 The table below contains the data for a one-hour unit hydrograph. Time Q (hr) (cfs/in) 0.0 0.5 1.0 1.5 2.0 2.5 3.0 3.5 4.0 4.5 5.0 0 145 246 359 979 432 246 134 65 32 0 (a) Determine the area of the watershed to which this unit hydrograph corresponds. Report your answer in acres. (b) Assume a very intense 3-hour storm occurs shortly after a rainy period, so the ground is very saturated. The runoff from the first one-hour interval of the storm totals 0.5 in., the runoff from the second one-hour interval is 2.5 in, and the runoff from the third one-hour interval totals 1.7 in. The baseflow during and after the storm is 80 cfs. Derive the storm hydrograph for this 3-hour storm. table that clearly indicates how you used the unit hydrograph, sample calculations Provide a with sufficient explanation, explanatory sketches, and a graph of the storm hydrograph. (c) Determine the peak discharge that will occur in the river if this 3-hour storm occurs.