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Homework - 1: University of Duhok College of Engineering Water Resources Engineering

The document is a student's homework on hydrology that includes: 1) A record of annual rainfall over 22 years at station A. 2) The student is asked to estimate the annual rainfall for return periods of 10 and 50 years. 3) Determine the probability of annual rainfall exceeding 100cm at station A. 4) The student provides the calculations and determines: the 10 year rainfall is 139cm, the 50 year rainfall is 184cm, and the probability of rainfall exceeding 100cm is 0.3876.

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Ammar Medeni
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54 views3 pages

Homework - 1: University of Duhok College of Engineering Water Resources Engineering

The document is a student's homework on hydrology that includes: 1) A record of annual rainfall over 22 years at station A. 2) The student is asked to estimate the annual rainfall for return periods of 10 and 50 years. 3) Determine the probability of annual rainfall exceeding 100cm at station A. 4) The student provides the calculations and determines: the 10 year rainfall is 139cm, the 50 year rainfall is 184cm, and the probability of rainfall exceeding 100cm is 0.3876.

Uploaded by

Ammar Medeni
Copyright
© © All Rights Reserved
We take content rights seriously. If you suspect this is your content, claim it here.
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Download as PDF, TXT or read online on Scribd
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University of Duhok

College of Engineering

Water Resources Engineering

Homework - 1
Frequency of Return period

Student Name: Ammar Mohammad Abdullah

Stage: 3
Course: Hydrology Tutorials
Instructor: Zahraa Mahmood Klari
Q-the record of annual rainfall at station A covering a period of
22 years is given below: (a) Estimate the annual rainfall with
return period of 10 years and 50 years, (b) What would be the
probability of an annual rainfall of magnitude equal to or
exceeding 100 cm occurring at station A?
Solution:

Annual Annual Return


Probability Return m Probability
m Rainfall Rainfall
m period m period
rank p= rank p=
(cm) N +1 T=1/p (cm) N +1
T=1/p
1 160 0.043 23.00 12 90 0.522 1.92
2 143 0.087 11.50 13 89 ---- ----
3 130 0.130 7.67 14 89 0.609 1.64
4 125 0.174 5.75 15 85 0.652 1.53
5 120 0.217 4.60 16 8.4 0.696 1.44
6 112 0.261 3.83 17 8.3 0.739 1.35
7 108 0.304 3.29 18 8.0 0.783 1.28
8 106 0.348 2.88 19 7.8 0.826 1.21
9 102 0.391 2.56 20 7.6 0.870 1.15
10 96 0.435 2.30 21 7.5 0.913 1.10
11 95 0.478 2.09 22 6.0 0.957 1.05
From The figure below:
• For the return period=10 year, The rainfall magnitude= 139 cm
• For the return period=50 year, The rainfall magnitude=184 cm
• For rainfall = 100 cm , T= 2.58 years ,
P = 1/2.58 =0.3876
The rainfall magnitude(m)

Return period T in years

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