In a trench that is 18" wide with sewage flowing at a depth of 2', if the velocity of the sewage is 1.5 feet per second, what is the flow rate in gallons per minute?

To find the flow rate of sewage in gallons per minute, the first step is to calculate the cross-sectional area of the flow and then use that to determine the flow rate.

1. Calculate the Cross-Sectional Area: The trench is 18 inches wide, which converts to 1.5 feet (since there are 12 inches in a foot). The depth of the sewage is 2 feet. The cross-sectional area can be calculated by multiplying the width by the depth: [

\text{Area} = \text{Width} \times \text{Depth} = 1.5 \text{ ft} \times 2 \text{ ft} = 3 \text{ ft}^2 ]

2. Calculate the Flow Rate in Cubic Feet per Second: The flow rate (discharge) can be calculated by multiplying the cross-sectional area by the velocity of the sewage: [ \text{Flow Rate (cubic feet per second)} = \text{Area} \times \text{Velocity} = 3 \text{ ft}^2 \times 1.5 \text{ ft/s} = 4.5 \text