1- Using the total direct runoff hydrograph given below, derive a unit hydrograph for the1715-ac drainage area. 2- What return period must a highway engineer use in designing a critical

underpass drain to accept only a 10 percent chance of occurrence of a storm event in the next 5 years? 3- Calculate the probability of 100-year storm over 30-year period. 4- A 6 h unit hydrograph for a catchment of area 1000 km? can be approximated as a triangle with base of 69 hours. Calculate the peak discharge of this unit hydrograph. 5- A small stream has trapezoidal cross section with base width of 10 m and side slopes 1Horizontal : 1 vertical in a reach of 5000 m. During a flood the high level record at the ends of reach are as below: