CIV E 530 - OPEN-CHANNEL HYDRAULICS
FALL 2013
HOMEWORK No. 13

  1. Calculate the fall velocity of a spherical quartz particle of diameter ds = 0.1 and water temparature T = 24 oC. Use ONLINE FALL VELOCITY.

  2. Calculate the sediment yield by the Dendy and Bolton formula for a 240-sq mi watershed with 4.5 in of annual runoff. Use ONLINE DENDY BOLTON.

  3. Based on the Shields criterion, determine whether a 2.7-mm quartz particle is at rest or moving under a 5-ft flow depth with channel slope So = 0.0001. Assume T = 68 oF. For what flow depth (to an accuracy of 0.01 inch) will the particle start to move?

  4. Given d = 10 ft, b = 250 ft, So = 0.0001, and d50 = 0.5 mm, calculate the bed material transport rate in tons/day by the Duboys formula. Use ONLINE DUBOYS.

  5. Using ONLINE MODIFIED EINSTEIN, calculate total sediment discharge for the following data set:

    1. Discharge Q = 280 cfs

    2. Mean velocity u = 2.4 fps

    3. Average depth d = 1.3 ft

    4. Width w = 130 ft

    5. Water temperature t = 68 oF.

    6. D65 = 0.00105 ft

    7. D35 = 0.00075 ft

    8. Measured concentration C = 235 ppm

    9. Vertical distance not sampled dn = 0.3

    10. Mean water depth at sampled verticals ds = 1.45 ft.

    11. Number of size fractions: Normal

    12. Fraction of bed material in each size range ib: 0.,0.,0.38,0.52,0.06,0.02,0.02,0.,0.

    13. Percentage of suspended material in each size range Q's (9 values): 22.,25.,42.,11.,0.,0.,0.,0.,0.

    Use default Z' mode.