To calculate the water flow rate in an open channel, we use the following formula for flow rate $Q$:

$Q = A \cdot V$

where:

• $Q$ is the flow rate (in cubic feet per second, or ft³/s),
• $A$ is the cross-sectional area of flow (in square feet, or ft²),
• $V$ is the velocity of the water (in feet per second, or ft/s).

Step 1: Calculate the cross-sectional area of flow

The cross-sectional area $A$ of the open channel can be calculated as:

$A = \text{width} \times \text{depth}$

Given:

• Width of the channel = 3 feet,
• Depth of the water = 1.6 feet.

So,

$A = 3 \, \text{ft} \times 1.6 \, \text{ft} = 4.8 \, \text{ft}^2$

Step 2: Calculate the flow rate

Now, using the velocity $V = 2 \, \text{ft/s}$, we can calculate the flow rate:

$Q = A \cdot V = 4.8 \, \text{ft}^2 \times 2 \, \text{ft/s} = 9.6 \, \text{ft}^3/\text{s}$

Final Answer:

The water flow rate in the open channel is $9.6 \, \text{ft}^3/\text{s}$.

Would you like further details on how flow rates can vary, or any other questions?

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1. How does the slope of the channel affect the water flow rate?
2. What is the effect of friction on the velocity of water in open channels?
3. How can you calculate flow rate if the channel shape is irregular?
4. What methods can be used to measure water velocity in the field?
5. How does sediment in water influence the calculation of flow rate?

Tip: When measuring flow in real situations, ensure that the velocity is an average of the depth profile, as surface velocities can differ from bottom velocities.