47.3.3. Lacey’s Regime Equations

Try these first

1. 1.

   What does the velocity equation V = k * f^(1/2) * R^(2/3) represent?

   Hint

   Focus on how velocity relates to channel dimensions and sediment.

2. 2.

   Explain what the silt factor is in Lacey's theory.

   Hint

   Think about how sediment influences flow characteristics.

3. 3.

   What is the formula for calculating the velocity in Lacey's equation?

   • V = k * f^(1/2) * R^(2/3)
   • V = Q/A
   • V = P/Q

   Hint

   Recall how velocity interrelates with silt and hydraulic conditions.

4. 4.

   True or False: The Silt Factor is related to channel design but not to sediment size.

   • True
   • False

   Hint

   Think of the definition of the silt factor in context.

5. 5.

   If you are designing a channel with a mean sediment size of 2mm, what is the silt factor? How would this affect the channel’s velocity?

   Hint

   Use the silt factor equation to find your answer.

6. 6.

   A channel is found to have a discharge of 10 m³/s with a velocity of 2 m/s. Calculate the area and describe how changes in area affect the design.

   Hint

   Identify what happens when the area is adjusted in channel properties.