Standard Practice for (Analytical Procedure) Determining Transmissivity and Storage Coefficient of Confined Nonleaky or Leaky Aquifer by Constant Drawdown Method in Flowing Well

Importancia y uso:

5.1 Assumptions—Leaky Aquifer: 

5.1.1 Drawdown (s_W) in the control well is constant,

5.1.2 Well is infinitesimal diameter and fully penetrates aquifer,

5.1.3 The aquifer is homogeneous, isotropic, and areally extensive, and

5.1.4 The control well is 100 % efficient.

5.2 Assumptions—Nonleaky Aquifer: 

5.2.1 Drawdown (s_W) in the control well is constant,

5.2.2 Well is infinitesimal diameter and fully penetrates aquifer,

5.2.3 The aquifer is homogeneous, isotropic, and areally extensive,

5.2.4 Discharge from the well is derived exclusively from storage in the nonleaky aquifer, and

5.2.5 The control well is 100 % efficient.

5.3 Implications of Assumptions: 

5.3.1 The assumptions are applicable to confined aquifers and fully penetrating control wells. However, this practice may be applied to partially penetrating wells where the method may provide an estimate of hydraulic conductivity for the aquifer adjacent to the open interval of the well if the horizontal hydraulic conductivity is significantly greater than the vertical hydraulic conductivity.

5.3.2 Values obtained for storage coefficient are less reliable than the values calculated for transmissivity. Storage coefficient values calculated from control well data are not reliable.

Note 7: The quality of the result produced by this standard is dependent on the competence of the personnel performing it, and the suitability of the equipment and facilities used. Agencies that meet the criteria of Practice D3740 are generally considered capable of competent and objective testing/sampling/inspection/etc. Users of this standard are cautioned that compliance with Practice D3740 does not in itself assure reliable results. Reliable results depend on many factors; Practice D3740 provides a means of evaluating some of those factors.

Subcomité:

D18.21

Volúmen:

04.08

Número ICS:

13.060.10 (Water of natural resources)

Palabras clave:

aquifers; aquifer tests; control wells; groundwater; observation wells; storage coefficient; transmissivity;