CE445-APPLIED HYDROLOGY
SPRING 2001
FIRST MIDTERM
MARCH 6, 2001, 1230-1345

Name: ______________________ S.S. No. _____________ Grade: _______

Instructions: Closed book, closed notes. Use engineering paper. When you are finished, staple your work in sequence (1 to 4), and return this sheet with your work.

  1. (20%) A 265-km2 basin has 750 mm of mean annual precipitation, and the mean annual outflow is 1.9 m3 s-1. What percentage of precipitation is abstracted by the catchment on a mean annual basis?

  2. (20%) Fit a Horton infiltration formula to the following measurements:

    Time (hr) f (mm/hr)
    1 2.75
    2 1.90
    infinity 1.50

  3. (20%) Calculate evaporation rate by the Penman method for the following atmospheric conditions: air temperature Ta = 20oC; net radiation Qn= 620 ly/day; wind speed v2 = 150 km/day; relative humidity RH= 75%.

  4. (40%) Please answer questions in a brief statement.

    1. Why does precipitation depth and intensity decrease with areal coverage?
    2. How many orders of magnitude does infiltration rate vary in practice?
    3. What is the Bowen ratio?
    4. What is the difference between potential and actual evapotranspiration?
    5. What is baseflow? Where does it come from?
    6. To what do you attribute the form of the Creager curves?
    7. A riverbed profile is usually concave when observed from above. To what do you attribute convexities in the profile?
    8. To what five factors is to be attributed the recurrence of debris flows in the San Gabriel Mountains of Northeast Los Angeles?