2.1. Calculating Area and Wetted Parameters

Try these first

1. 1.

   What is the formula for calculating area in a trapezoidal channel?

   Hint

   Think of how we calculate areas of triangles and rectangles together.

2. 2.

   Define wetted perimeter (P).

   Hint

   Consider all sides of the channel that the water touches.

3. 3.

   What is the hydraulic radius?

   • A / P
   • P / A
   • A + P

   Hint

   Remember how these terms relate to the flow in a channel.

4. 4.

   Is Manning's equation used for both circular and trapezoidal flow calculations?

   • True
   • False

   Hint

   Think about the versatility of this equation.

5. 5.

   Calculate the discharge for a trapezoidal channel with a bottom width of 8m, depth of 2m, and a side slope of 1:2. Given n = 0.015 and S₀ = 0.002.

   Hint

   Break it into steps: Area first, then perimeter, finally use Manning's equation.

6. 6.

   For a circular pipe with a diameter of 1.0m and flow depth of 0.4m, calculate the discharge using n = 0.013 and S₀ = 1/1000.

   Hint

   Focus on finding theta to determine the submerged area.