CIV E 634 - SURFACE WATER HYDROLOGY
SPRING 2007
HOMEWORK 1:   EVAPORATION

  1. Derive the Penman equation (Eq. 2-36, page 46 of text).

  2. Verify Example 2-5 in the text by running PENMAN in onlinehydro.sdsu.edu.

  3. Calculate the evapotranspiration rate of the reference crop (clipped grass 0.12-m high) by the Penman-Monteith method for the month of March, with the following atmospheric conditions: air temperature Ta = 20 oC; net radiation Qn = 600 cal/cm2/d; wind speed v2 = 200 km/d; relative humidity RH = 70%; and atmospheric pressure = sea level (1013.2 mb).

  4. Verify your results of Problem 3 by running PENMAN-MONTEITH in onlinehydro.sdsu.edu.

  5. Using PENMAN-MONTEITH, study the sensitivity of the reference crop evapotranspiration to the relative humidity. Vary RH between 0% and 100% and report the results. What is the ratio of ETo for RH= 0% to RH= 100%?

  6. Given the reference crop (clipped grass 0.12-m high), with air temperature Ta = 20 oC; net radiation Qn = 600 cal/cm2/d; and atmospheric pressure = sea level (1013.2 mb). At what wind speed will the RH=0%/RH=100% ratio equal 2?

  7. Use THORNTHWAITE in onlinehydro.sdsu.edu to calculate the annual PET for Ramona (32oN) with the following mean monthly temperatures (January to December): 11. 13. 14. 16. 18. 21. 22. 20. 18. 16. 12. 12.

  8. Verify Example 2-6 in the book by running BLANEY-CRIDDLE in onlinehydro.sdsu.edu.

  9. Verify Example 2-7 in the book by running PRIESTLEY-TAYLOR in onlinehydro.sdsu.edu.
Submit all onlinehydro.sdsu.edu printed output.