Work out well yield instantly with clear inputs, formula shown and shareable results.
Specific capacity, the pumping rate divided by the drawdown it causes, is the single most useful number from a well test because it predicts how the well will behave at other rates. Sustained abstraction is normally set at about 70 percent of the tested rate so the aquifer is not drawn down to the pump intake in dry seasons.
Specific capacity
Sc = test flow GPM / drawdown ft
Sustainable rate
Recommended GPM = 0.7 x tested rate
Sc = test flow GPM / drawdown ft. Specific capacity, the pumping rate divided by the drawdown it causes, is the single most useful number from a well test because it predicts how the well will behave at other rates.
A short test does not reveal seasonal decline or interference from nearby wells. The margin protects the pump from breaking suction when water levels fall.
This calculator takes 4 inputs: Static water level, Level while pumping, Test pumping rate, Test duration. The pre-filled defaults are a realistic worked example — replace them with your own site or project figures.