a. Compute the Unit Hydrograph (UH) in m3/s per mm for the watershed. Use straight-line method for base flow separation. No need to plot. Just show the tabular values. Time (hour) Streamflow (m³/s) 1 132 2 250 3 400 4 740 5 530 6 420 7 350 8 220 9 132 b. The same watershed was subjected to 3 hours of rainfall with the corresponding excess precipitation per hour: P₁-14 mm, P2-15 mm and P3=11 mm. Using the UH computed from the previous item, determine the actual streamflow hydrograph.

a. Compute the Unit Hydrograph (UH) in m3/s per mm for the watershed. Use straight-line method for base flow separation. No need to plot. Just show the tabular values. Time (hour) Streamflow (m³/s) 1 132 2 250 3 400 4 740 5 530 6 420 7 350 8 220 9 132 b. The same watershed was subjected to 3 hours of rainfall with the corresponding excess precipitation per hour: P₁-14 mm, P2-15 mm and P3=11 mm. Using the UH computed from the previous item, determine the actual streamflow hydrograph.

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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QUESTION For a 2-hour, 10 mm/h intensity rainfall, the hydrograph given in Table is observed. The area of watershed is 400 km². Table; Propeller Readings Time 0 2 4 6 8 10 12 Flow Rate (m³/s) 16 22 26 38 53 46 36 14 16 18 32 36 22 a) Obtain 2-hour unit - hydrograph for the considered flow section. 20 22 24 18 16 16
QUESTION For a 2 hour, 10 mm/h intensity rainfall, the hydrograph given in Table is observed. The area of watershed is 400 km². Table; Propeller Readings Time 0 2 4 6 8 Flow Rate (m³/s) 16 22 26 10 12 14 16 18 20 38 53 46 36 32 36 22 22 24 18 16 16 a) Obtain 2 hour unit - hydrograph for the considered flow section. b) Obtain 6 hour unit - hydrograph for the considered flow section. c) Obtain the hydrograph of the rainfall with 6 hour duration and 12 mm/h intensity.
The observed rainfall and discharge of a catchment is given the table. The catchment area is 0.23Km^2. Time (h) 1 2 3 4 5 6 7 8 00 9 10 11 12 13 Rainfall (mm) 0 0 2 6 10 8 2 0 0 0 0 0 0 1. Estimate the base flow. 2. Estimate the surface runoff. 3. Estimate the initial loss 4. Estimate the continuous loss using phi method. Discharge (M3/s) 20 20 20 20 30 50 40 35 25 21 20 20 20
1. The 1-hr unit hydrograph for a watershed is given below. Determine the runoff for the third time interval from this watershed for the storm pattern given. The abstractions have a constant rate of 0.3 in/h. Time (hr) Precipitation (in) Unit hydrograph (cfs) 1 2 | 3 4 5 0.5 1.0 1.5 0.5 10 100 200 150 100 50
Develop the Total I 1-hour Unit Hydro o Index is 2 cm Assume a baseflow of 2 m/s. SHOW SAMPLE CALCULATION BELOW for all types of calculations you need to do. ograph (TH) from a 3-hour duration storm on a watershed whose 1(UH) is given in the first two columns of the table below. Storm Data: Time 1" hour 2nd hour 3rd hour Rainfall depth (cm) 4 3 2.5 Computation Table (Please Fill-in the Blanks as needed) I-hr UH Time (hr) Direct Runoff per period and baseflow (use space as needed) Total Hydrograph Q (cms) (m'/s) 58 110 96 53 26 14 8. 9 4 10 3 11 1.5 12 13 14 15 16 Sample calculation (with proper units): Runoff depth sample calculation needed.A completely-worded sample calculation using Principle of Linearity is a must for any partial credit. Must show unit cancellations. Additional space in the nex page.
The average rainfall values over a catchment in three successive 2-hour intervals are 3, 5 and 2 cm, respectively. The index for the catchment is taken as 0.2 cm/hour. The 2 hour unit hydrograph ordinates are given in table below. Time in hrs. Discharge m 0 2 4 m³/sec 0 10 40 6 14 16 70 50 20 10 6 0 Base flow can be taken as 7 m³/sec at the beginning of the storm linearly increasing to 9 m³/sec at 10 Hrs. after the beginning and then linearly decreasing to 8 m³/sec at 4 Hrs. after the end of direct run off. Compute the resultant flood hydrograph. 8 10 12
The following table lists a streamflow hydrograph with a time interval of 10 minutes from a watershed, and the related storm occurred at time steps 3, 4 and 5 with the rainfall depths of 20 mm, 4 mm, and 11 mm, respectively. The ø-index is 30 mm/hr. (i) Use the straight- line method to separate the baseflow. (ii) Use the deconvolution method to derive and plot the 10-minute unit hydrograph. (iii) Calculate the watershed area and determine the time of concentration. Time step (10 minutes) 1 3 5 6. 7 8 9 2 4 Discharge (m³/s) 1.85 1.73 5.48 9.68 8.87 5.39 4.58 2.63 | 2.51
1-In a storm, the excess rainfall of 0.5, 0.7,0 and 0.8 cm occurred in four successive hours. If the base flow is 0.5 m³/s, find the 1-hr unit hydrograph where the storm hydrograph is given below (Q in m³/s and t in hr): t 0 Q 0.5 1 2 3 4 5 44.5 110.5 85.5 102.8 94 6 38.4 7 18.6 8 9 10.9 5.3 10 11 0.5 2.9
5. From the 1mm 6 hour unity hydrograph given below, derive the 2 hour unit hydrograph. Time 12 18 24 30 (hrs) UH 15 8 3.6 0.6 0.0 (cumecs) What would be the peak surface runoff resulting from 3mm of rainfall falling in the space of two hours?
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
Problem 2 A watershed having an area of 28 km² records the following rainfall data. Time Rainfall Time Rainfall (mm) 0.6 (mins) 150 180 210 (mins) 30 (mm) 3.4 60 1.1 2.2 90 1.7 1.3 120 2.5 240 0.2 Determine the infiltration rate (in mm/hr) using the o-index method if the runoff volume was found to be 224,000 m³.
Sample Problem Given the following observed flows from a storm of 3-hr duration on a watershed with a drainage area of 10 sq. km. Assume that the base flow at the end of the runoff period is 6.0 cubic meters per second. TIME Q (hours) (m³/s) 1 6.0 2 15 3 25 4 21 5 13 6 6.0 1. Determine the direct runoff hydrograph by separating the baseflow. 2. Derive the unit hydrograph (for 1 centimeter of direct runoff) for the 3-hr rainfall.