A Lift Station Basin Measures 10 by 30 Feet. If the Water Level Drops 3 Feet in One Hour, Approximately How Many Gallons Per Minute Is the Pump Moving?

A Lift Station Basin Measures 10 by 30 Feet. If the Water Level Drops 3 Feet in One Hour, Approximately How Many Gallons Per Minute Is the Pump Moving?

• A. 50 GPM
• B. 112 GPM
• C. 250 GPM
• D. 500 GPM

Answer: (B)

The pump’s flow is found by turning a drop in depth into a volume and then dividing by time. The basin is 10 ft by 30 ft, so its surface area is 10 × 30 = 300 square feet. A 3-foot drop over that area means the volume removed is 300 × 3 = 900 cubic feet. Since 1 cubic foot holds about 7.48 gallons, 900 ft^3 ≈ 900 × 7.48 ≈ 6720 gallons. This amount leaves the basin in one hour (60 minutes), so the pump flow is 6720 ÷ 60 ≈ 112 gallons per minute. Therefore, about 112 GPM.

The pump’s flow is found by turning a drop in depth into a volume and then dividing by time. The basin is 10 ft by 30 ft, so its surface area is 10 × 30 = 300 square feet. A 3-foot drop over that area means the volume removed is 300 × 3 = 900 cubic feet. Since 1 cubic foot holds about 7.48 gallons, 900 ft^3 ≈ 900 × 7.48 ≈ 6720 gallons. This amount leaves the basin in one hour (60 minutes), so the pump flow is 6720 ÷ 60 ≈ 112 gallons per minute. Therefore, about 112 GPM.