The runoff coefficient is directly proportional to the rate of runoff. True False What condition will convert a type C hydrograph to a type A hydrograph? A. Time of recession = duration of storm ● B. Time of concentration = duration of storm OC. Time of recession = duration of runoff OD. Time of concentration = duration of runoff

The land use of an area and the corresponding runoff coefficients are as follows: S. Land use No. 1. 2. 3. 4. Roads Lawn Area Runoff (ha) coefficient 10 20 Residential area 50 Industrial area 20 0.70 0.10 0.30 0.80 What is the equivalent runoff coefficient?

please answer if sure it is correct, will thumbs up if correct.

4. For an urban area, the land use of the area and the corresponding runoff coefficients are given below. Calculate the equivalent runoff coefficient. Assume the intensity of rainfall as 103.8 mm/hr. Estimate the peak flow rate for this area. (1 ha = 10 m) Runoff coefficient Land use Roads Residential area Industrial area Area 0.7 50 0.3 10 0.8

1. A 160-acre drainage basin has the following characteristics: Land Use Residential, flat, 60% impervious Residential, flat, 30% impervious Concrete or sheet asphalt pavement Turf Meadows Forested Area * for a range of values, the runoff coefficient can be calculated as an average value. Rainfall Intensity (in/hr) Find the peak runoff from the drainage area for a 20-minute duration storm with a return frequency of 25-years? 20 18 16 14 2 0 0 Frequency (years) 100 50 25 10 10 Area % 20 30 5 25 20 20 30 Duration (min) Coefficient (C)* 0.55 0.40 0.85 0.25 0.2 40 50 60

2) Assume the total runoff hydrograph was measured over 4 hours, in 30 minute intervals. The baseflow is 10 cfs and the watershed is 100 acres. Determine the 30 min unit hydrograph. Time (min) Runoff (cfs) 0 10 30 50 60 80 90 160 120 210 150 180 180 155 210 110 240 60

The stream flow data for a basin with an area of 3500 km2 are given in the table 1, a. Separate the base flow using: (i) Constant discharge method (ii) Constant Slope Base flow method b. Determine the Equivalent runoff depth of the direct runoff. Table 1: Accumulative Time Total Flow (m/s) Number 8:00 am 16 9:00am 15 3 10:00am 35 11:00am 60 5 12:00 Noon 80 1:00pm 110 7 2:00pm 80 8 3:00om 60 4:00pm 5:00pm 44 10 38 11 6:00pm 33 12 7:00pm 29 13 8:00pm 25 14 9:00pm 15

hydrology problem: use the S-method

a) Calculate the peak runoff rate of the watershed whose area is 600 ha & the rainfall intensity is given 2.5cm/hr. Take Runoff coefficient C = 0.18

Will the following rectangular channel (base = 8 ft, height = 3 ft) be able to provide adequate conveyance for the drainage area shown in the figure below? The channel roughness (n) is 0.02 and slope is 0.01 (ft/ft). Use the rational method and assume a runoff coefficient of 0.75 and rainfall intensity of 2.5 in/hr to calculate the runoff. 2,000 ft 700 ft Channel 500 ft