6.2. The design storm of a watershed has the depths of rainfall of 4.9 and 3.9cm for the consecutive Ihr periods. The Ihr UH can be approximated by a triangle of base 6hr with a peak of 50 m³/s occurring after 2hr from the beginning. Compute the flood hydrograph assuming an average loss rate (D-index) of 9mm/hr and constant base flow of 10 m³/s. What is the area of the watershed? Ans. (10, 110, 285, 310, 222.5, 135, 47.5, 10), A=54Km² M

6.2. The design storm of a watershed has the depths of rainfall of 4.9 and 3.9cm for the consecutive Ihr periods. The Ihr UH can be approximated by a triangle of base 6hr with a peak of 50 m³/s occurring after 2hr from the beginning. Compute the flood hydrograph assuming an average loss rate (D-index) of 9mm/hr and constant base flow of 10 m³/s. What is the area of the watershed? Ans. (10, 110, 285, 310, 222.5, 135, 47.5, 10), A=54Km² M

Structural Analysis

6th Edition

ISBN:9781337630931

Author:KASSIMALI, Aslam.

Publisher:KASSIMALI, Aslam.

Chapter2: Loads On Structures

Section: Chapter Questions

Problem 1P

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6.2. The design storm of a watershed has the depths of rainfall of 4.9 and 3.9cm for the consecutive Ihr periods. The Ihr UH can be approximated by a triangle of base 6hr with a peak of 50 m³/s occurring after 2hr from the beginning. Compute the flood hydrograph assuming an average loss rate (D-index) of 9mm/hr and constant base flow of 10 m³/s. What is the area of the watershed? Ans. (10, 110, 285, 310, 222.5, 135, 47.5, 10), A=54Km²
An effective rainfall of 2-hour duration produced a flood hydrograph peak of 200 m³/s. The flood hydrograph has a base flow of 20 m3/s. If the spatial average rainfall in the watershed for the duration of storm is 2 cm and the average loss rate is 0.4 cm/hour, the peak of 2- hour unit hydrograph (in m³/s-cm, up to one decimal place) is
A direct-runoff hydrograph due to an isolated storm was triangular in shape with a base of 60h and a peak of 100 m³/s. If the catchment area is 500 km², the effective rainfall of the storm is (a) 10 cm (b) 2.16 cm (c) 21.6 cm (d) 1.08 cm
Q2 A flaod was measured from a catchment of 500 square kilometers. The direct runoff from this flood was found to be 3.25 cm. The time distribution of the rainfall is given below In Table. Find the W index for this storm by considering 0.5 cm Interception and depression storage lasses. Alsa find total infiltrated volume of water. Time (hr.) 1 2 3 1.2 1.45 5 6 7 Total rainfall 2.2 3.65 5.09 3.18 1.97 18.74
Q- The average rainfall for a 3 hour duration storm is 2.7 cm and the loss rate is 0.3 cm/hr. The flood hydrograph has a base flow of 20 m³/s and produces a peak flow of 220 m³/s. Find the peak of a 3-h unit hydrograph.
PROBLEM 2: Based on the given RIDF data, the relationship of the rainfall intensity and the time can be described using the general equation A. Determine the design peak flow for a 25-year return period flood, for an urban catchment that has an area of 0.75 sq. km. The slope of the catchment is 0.006 and the maximum length of flow is 900 meters. Assume runoff coefficient of 0.40. GIVEN: Rainfall-Intensity-Duration-Frequency (RIDF) Data (25-year return period) Duration, mins Rainfall, mm Intensity, mm/hr 5 10 15 20 30 45 60 27.3 40.7 53.1 61.1 75.1 91.1 101.6 327.6 244.2 212.4 183.3 150.2 121.5 101.6 General Equation A: Where: a, b, &c are regression constants a = 1098.984 a i = (te + b)e b = 3.46 0.569
A 20-minute rainfall event occurred at a small catchment (without any base flow), which has 2 branch rivers (or tributaries) with individual sub-catchments. This storm generated a triangular runoff hydrograph with peak flow of 139 L/s at the catchment outlet. Base of the triangular hydrograph was 1 hr 12 minutes. The rainfall distribution and other relevant data is given in Table 1. Assume that the rainfall was uniform over the subcatchments. Calculate the followings: i) Total rainfall volume fallen on the catchment. ii) Total runoff volume generated from the catchment during this rainfall event. iii) Average runoff coefficient for the whole catchment for that particular rainfall event. Table 1: Data for Question 1(b) Sub-catchment Catchment Rainfall No. Area (ha) (mm) 1 1.24 37 0.58 20
A 6-hour rain of average intensity 2 cm/hour falls over the fern leaf type catchment as shown in Figurebelow. The time of concentration from the lines AA, BB, CC and DD are 1, 2, 3 and 4 hours,respectively, to the site 0 where the discharge measurements are made. The values of the runoffcoefficient C are 0.5, 0.6, and 0.7 for the 1st, 2nd and 3rd hours of rainfall respectively and attain aconstant value of 0.8 after 3 hours. Draw surface runoff hydrograph from the runoff collected from thecatchment and also calculate volume of direct Runoff.
Q2.The mass curve of an isolated storm in a 500 ha watershed is as follows: Time from start (h) 4 6. 8 10 12 14 16 Cumulative rainfall 0.8 2.6 4.1 7.3 10.8 11.8 12.4 12.6 (cm) 1- Draw the hyetograph for storm. 2- Estimate the o-index of the storm at the outlet of the watershed as 0.340 Mm³. the direct runoff produced by the storm is measured
... The successive of 3hr ordinates of a 6hr UH for a particular basin are 0, 15, 36, 30, 17.5, 8.5, 3, and 0 m³/s, respectively .The flood peak observed due to a 6hr storm was 150 m³/s.Assuming a constant base flow of 6 m³/s and an average storm loss of 6mm/hr. Determine the depth of storm rainfall and the stream flow at the successive 3hr interval.
The average rainfall for a 3hr duration storm is 2.7cm, and the loss rate is 0.3cm/hr. The flood hydrograph has a constant base flow of 20 m3/s and produces a peak flow of 210 m3/s. Determine the peak of a 3-hr triangular Unit Hydrograph?
If fo = 0.7 in./hr, fc = 0.2 in./hr, and K = 0.5 hr-1, determine the distribution of losses and the depth of rainfall excess for 2-hour storm with intensity of 1.3 in/hr.