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Unformatted text preview: Florida International University Department of Civil and Environmental Engineering CWR3103 – Water Resources Engineering Midterm Examination This is an open book, open notes examination. It is subject to FIU Honor Code. Please follow these general instructions: 1. Choose 3 problems to solve. Do not turn in solutions for more than 3 problems. 2. Show all work and equations used. 3. Explain clearly your calculation steps. 4. Write answers legibly. 5. Sign the pledge below. 6. Return this exam sheet with your solution to Dr. Miralles before you leave the classroom. No sheets will be accepted afterwards. I, undersigned, pledge my honor that I have neither given nor received aid on this examination. Signature:________________________________________________ Printed name: Problem 1: Compute the runoff depth from a 7‐inch rainfall on a 1500 acre watershed that has hydrologic groups that are 40 % group A, 40 % group B and 20 % group C interspersed throughout the watershed. The land use is 90 % residential that is 30 % impervious, and 10 % paves roads with curbs. What was the runoff depth for this watershed for this same rainfall before development occurred? The land used prior to development was pasture and range land in poor condition. Assume AMC II conditions. Problem 2: Use the National Weather Service (Chen, 1983) method to estimate the 10‐year, 25‐year and 100‐year IDF curves for Miami, FL. What is the 25‐year, 24‐hr duration rainfall depth in Miami? Problem 3: A 20 ha townhouse development is to be drained by a single drainage inlet. The average runoff coefficient for the site is estimated to be 0.7, Manning’s n for overland flow is 0.25, the average overland flow length is 100 m, and the average slope of the site towards the inlet is 0.6%. The site is located in an area with an IDF curve given by i = 1020/(td + 8.7)0.75 where i is the rainfall intensity in mm/h and td is the duration in minutes. What is the peak runoff rate expected at the drainage inlet? Problem 4: For Cairo (Egypt), the average net radiation in July is 185 W/m2, air temperature is 28.5 C, relative humidity is 55 % and the wind speed is 2.7 m/s at a height of 2 m. Calculate the evaporation rate in Cairo using the Energy, Diffusion‐Convection and Penman methods. Calculate the evapotranspiration rates for grass and alfalfa using the Penman‐Monteith method. Assume a standard atmospheric pressure of 100 kPa, a surface roughness of 0.03 cm, and a boundary layer height of 1 m. ...
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This note was uploaded on 07/09/2011 for the course CWR 3013 taught by Professor Miralles during the Spring '09 term at FIU.
- Spring '09