Open Channel Flow: Drop

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Discharge Calculation in Open Channels



In a drop, water falls freely from a channel to some lower level. Rough estimates of flow could be made by measuring the depth of flow at drop. The required conditions are as follows:

  • The minimum straight upstream reach for approach channel shall be at least 20 times the end depth of approach channel.
  • Minimum Width of Channel shall be 300 mm
  • Critical depth shall be minimum 50 mm

The discharge calculation formula for drops is as given below;

Q=dc^1.5*sqrt g*b


Q = Discharge in cubic meter per second,

dc = Critical depth at drop in meters,

b = Width of Channel in meters,