ASTM International

Standard Test Method for Determining Specific Capacity and Estimating Transmissivity at the Control Well
 N D5472/D5472M

Annotation

This test describes a procedure for conducting a specific capacity test, computing the specific capacity of a control well, and estimating the transmissivity in the vicinity of the control well. Specific capacity is the well yield per unit drawdown at an identified time after pumping started.

This test method is used in conjunction with Test Method D4050 for conducting withdrawal and injection well tests.

The method of determining transmissivity from specific capacity is a variation of the nonequilibrium method of Theis (1)2 for determining transmissivity and storage coefficient of an aquifer. The Theis nonequilibrium method is given in Test Method D4106.

Limitations-The limitations of the technique for determining transmissivity are primarily related to the correspondence between the field situation and the simplifying assumptions of the Theis method.

The scope of this test method is limited by the capabilities of the apparatus.

All observed and calculated values shall conform to the guidelines for significant digits and rounding established in Practice D6026.

The procedures used to specify how data are collected/ recorded and calculated in this standard are regarded as the industry standard. In addition, they are representative of the significant digits that should generally be retained. The procedures used do not consider material variation, purpose for obtaining the data, special purpose studies, or any considerations for the user's objectives; and it is common practice to increase or reduce significant digits of reported data to commensurate with these considerations. It is beyond the scope of this standard to consider significant digits used in analysis methods for engineering design.