What is the numeric well yield given in the drawdown example?

• A. 129 gpm
• B. 45 gpm/ft
• C. 13.7 ft
• D. 435,000 gal

Answer: (A)

In a drawdown test, the well yield is the discharge rate you can sustain during pumping, expressed as a flow rate (gallons per minute). The example provides a steady pumping rate of 129 gpm, which is exactly the yield—the amount of water the well can supply per minute under test conditions. The other numbers correspond to different quantities you might encounter in drawdown analyses but aren’t the yield: 45 gpm/ft would be specific capacity (flow per foot of drawdown), 13.7 ft is the measured drawdown (how far the water level falls), and 435,000 gal would be a cumulative volume pumped or stored, not the sustained discharge rate. Therefore, 129 gpm is the correct representation of the well yield.