CIV E 638 - SEDIMENTATION ENGINEERING
FALL 2022
HOMEWORK No. 3:  CHANNEL MORPHOLOGY

  1. Use the Modified Lane method to calculate the sediment discharge Qs in metric tons per day, given the following hydraulic and sedimentological data: discharge Qw = 1 m3/s; bottom slope So = 0.001; hydraulic radius R = 1 m; particle size ds = 1 mm. Assume k1 = 0.01. Confirm with ONLINE MODIFIED LANE.

  2. Use the Modified Lane method to calculate the sediment discharge Qs in tons per day, given the following hydraulic and sedimentological data: discharge Qw = 100 cfs; bottom slope So = 0.002; hydraulic radius R = 1 ft; particle size ds = 0.8 mm. Assume the default k1 = 0.001. Confirm with ONLINE MODIFIED LANE.

  3. For the data of Problem 1, assume that a sediment retention basin retains 50% of the sediment discharge and the representative particle size downstream of the retention basin reduces to ds = 0.7 mm. According to the Modified Lane relation, what is the prevailing downstream slope So,2 produced by degradation?

  4. For the data of Problem 3, what downstream slope would be predicted by the Lane relation?