CIV E 445-APPLIED HYDROLOGY
SPRING 2011
SECOND MIDTERM
APRIL 11, 2010, 0730-0845
Name: _______________________ Red ID _________________ Grade: _______
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Instructions: Closed book, closed notes. Use engineering paper.
When you are finished, staple your work in sequence (1 to 3),
and return this sheet with your work.
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- (25%) What is the peak discharge for a 43-ha watershed with a rainfall intensity of 26 mm/hr.
Assume C= 0.75.
- (35%) A certain basin has the following 2-hr unit hydrograph (1 cm of rainfall), defined at hourly ordinates:
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Cumulative time (hr) | 0 | 1 | 2 | 3 | 4 | 5 | 6 | 7 | 8 | 9 | 10 | 11 | 12 | 0
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Flow (m3/s) | 0 | 5 | 15 | 30 | 60 | 70 | 60 | 55 | 45 | 35 | 25 | 15 | 5 | 0
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Calculate the composite flood hydrograph for the following effective storm pattern:
| Time (hr) | 0-3 | 3-6 |
| Effective rainfall (cm/hr) | 2 | 4 |
| Effective rainfall (cm) | 6 | 12 |
- (40%) Please answer in a brief statement:
- What is the upper size limit (in square miles) for a small catchment?
- What is the exponent of the rating (β) under turbulent Manning flow in overland flow?
- What are the four explicit variables (or parameters) in the runoff curve number methodology?
- What is the standard peak rate factor (PRF) in the NRCS synthetic unit hydrograph methodology?
- Which NRCS type storm (I, IA, II, or III) is the most intense? Where is it applicable?
- According to Gumbel, what is the return period of the mean annual flood?
- If an x-y paired data set describes a perfect circle when plotted, what is the correlation coefficient?
- What are the advantages and disadvantages of levees?
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