CIV E 445-APPLIED HYDROLOGY
FALL 2006
SECOND MIDTERM
NOVEMBER 13, 2006, 0730-0845

Name: _______________________ Red ID _________________ Grade: _______

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.

  1. (30%) An overland flow plane has the following characteristics:

    plane length L = 45 m;
    plane slope So = 0.006;
    Manning's n = 0.08;
    rainfall excess i = 65 mm/hr.

    Determine if the kinematic wave approximation is applicable to this set of overland flow conditions. Assume the exponent of the rating m = 5/3.

  2. (30%) A certain basin has the following 2-hr unit hydrograph (1 cm of rainfall), defined at hourly ordinates:

    Flow (m3/s) 0 5 15 30 60 70 60 55 45 35 25 15 5 0

    Calculate the flood hydrograph for the following effective storm pattern, defined at two 3-hr increments (6-hr total event duration).

    Time (hr) 3 6
    Effective rainfall (cm/hr) 3 5
    Effective rainfall (cm) 9 15

  3. (40%) Please answer briefly:

    1. What is the difference between potential and actual evapotranspiration?
    2. What is a "small" catchment in a hydrologic sense?
    3. What channel property is primarily responsible for the flow being kinematic?
    4. What are the four explicit variables (or parameters) in the runoff curve number methodology?
    5. What is the standard value of peak rate factor (PRF) of the NRCS unit hydrograph? Where does it come from?
    6. Which SCS type storm is the most intense? Where is it applicable?
    7. Why is the TR-55 method consistent with diffusion wave theory?
    8. What is the return period of the mean annual flood according to Gumbel?