A basin is divided by 1-h isochrones into four sub-areas of size 200, 250, 350 and 170 hectares from the upstream end of the outlet respectively. A rainfall event of 5-h duration with intensities of 1.7 cm/h for the first 2 h and 1.25 cm/h for the next 3 h occurs uniformly over the basin. Assuming a constant runoff coefficient of 0.5, estimate the peak rate of runoff.

A basin is divided by 1-h isochrones into four sub-areas of size 200, 250, 350 and 170 hectares from the upstream end of the outlet respectively. A rainfall event of 5-h duration with intensities of 1.7 cm/h for the first 2 h and 1.25 cm/h for the next 3 h occurs uniformly over the basin. Assuming a constant runoff coefficient of 0.5, estimate the peak rate of runoff.

Traffic and Highway Engineering

5th Edition

ISBN:9781305156241

Author:Garber, Nicholas J.

Publisher:Garber, Nicholas J.

Chapter16: Highway Drainage

Section: Chapter Questions

Problem 7P

See similar textbooks

Similar questions

B: The direct runoff hydrograph is 64hr and maximum discharge is 30 m/sec. If the observed runoff due to 12hr storm of uniform intensity is 0.5 cm/hr and the catchment area is 120 km². Determine the o index for the basin in cm/hr.
A 200-acre urban drainage area consists of three different watershed areas as follows: (i) 100-acre of Flat residential (30% impervious area); (ii) 60-acre of Moderately steep residential (50% impervious area); and (iii) 40-acre of Flat commercial (90% impervious area) = 20%. Using the rational formula, determine the runoff rate for a storm of 100-year frequency. Assume that the FHWA/NJ-82-004 rainfall intensity curves are applicable to this drainage area and the following land characteristics apply: fallow or minimum tillage cultivation ground cover with 3% average slope of overland area. Overland flow length = 0.5 miles.
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
The ordinates of a hydrograph of surface runoff resulting from 4.5cm of rainfall excess of duration 8 hours in a catchment are as follows. Determine the ordinates of the 8h unit hydrograph for this catchment. Tabulate your solution and plot the 8H-UH.
QUESTIONS The initial rainfall intensities of a storm during dry weather flow are 12, 16, 22, 45, 42, 38, 29, 15, 18, 25, 42, 38, 24, 12 and 3 mm/hr at 20 minutes interval. The area of basin is 750 km² and p index is 18 mm/hr. What will be the runoff volume of the basin, if the initial abstraction is 10 mm?
For the given rainfall data, compute the runoff volume if the index is 0.9 in/hr. The watershed area is 0.785 mi². t(hr) 0-3 3-5 5-8 8-11 11-12 i(in/hr) 1.20 2.10 1.30 1.00 0.80
Determine the peak runoff (Nearest whole number) from a 100-year storm for the watershed described below: Field 1: 192 acres, 2% slope, cultivated, sandy soil Field 2: 38 acres, 8% slope, pasture, tight clay soil Field 3: 40 acres, 11% slope, woodland, silt soil The drainage way is 4000 feet with a 0.1% slope.
For a precipitation event in a watershed of interest, Table 1 shows the Unit Hydrograph for the watershed on the left, and the excess rainfall at times 1, 2, and 3 on the right. Using the convolution method, find the direct and total runoff from the watershed. Assume the watershed has a constant baseflow of 8 ft³/sec. Table 1. Excess rainfall and Unit Hydrograph Unit Excess Time Time Hydrograph Rainfall (hrs) (ft³/(sec*in)) (hrs) (in) 1 36 1 0.3 2 92 2 0.2 3 63 3 1.1 4 18 5 5
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
A 100-acre watershed that is 80% Industrial and 20% newly graded areas (no vegetation). The watershed has soil group B. Determine the runoff volume for 10-year, 24-hr rainfall event (use the IDF below) 20.0 15.0 10.0 8.0 RAINFALL INTENSITY IN INCHES PER HOUR 6.0 4.0 6 0.1 0.08 0.06 0.04 0.02 5 VDOT B, D & E eqn. except for 1-year NOAA Atlas 14 Vienna/Tysons for 1-year 10 15 20 MINUTES SHINE RETURN PERIOD (YEARS) 30 40 50 60 N 10 DURATION NOAA Atlas 14 Vienna/Tysons 2 3 4 5 6 HOURS 8 10 12 سلسلي 18 24
A catchment area has a time of concentration of 20 minutes, an area of 20 has. and a runoff coefficient of 0.25. Estimate the peak discharge corresponding to a 25-year period if the intensity-duration-frequency for the storm in the area can be expressed by KT* i = D + a where i = intensity in cm/hr. T = return period in years, and D = duration of storm in hours; The coefficients are: K = 6.93, x = 0.189, a = 0.50 and n 0.878
The ordinates of a 6h-UH of a watershed having a drainage area of 393 km^2 are given below. For a storm over the watershed having excess rainfall of 5 cm for the first six hours and 15 cm for the second six hours, compute the direct runoff hydrograph ordinates and plot the hydrograph. Compute the depth of direct runoff in cm. Assuming constant baseflow of 100 m^3/s, compute the storm hydrograph ordinates and plot the hydrograph. (List all the DRH ordinates in order, separated by a single space.)