Equation 537 E The drawdown in a longterm pumping test of ar

E. The drawdown in a long-term pumping test of arn unconfined aquifer declines according to Equation 5-37 for several days and then becomes stable (i.e., no longer declines). List two reasons why this might occur.

Solution

1. The cone of depression will increase until the recharge to the well equals the pumping rate

2. When the hydraulic gradient becomes constant, then the drawdown will no longer declines