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D5472 – Standard Test Method Technical Guide
📐 Scope and Application
ASTM D5472/D5472M provides a standardized practice for conducting specific capacity tests in control wells. It defines specific capacity as the well yield per unit drawdown at a specified time after pumping initiation. This practice is used in conjunction with Test Method D4050 for conducting withdrawal and injection well tests. The primary output includes computing specific capacity and estimating transmissivity near the control well.
⚙️ Test Procedure and Key Parameters
The test procedure relies on the Theis nonequilibrium method, as detailed in Practice D4106, to derive transmissivity and storage coefficient values. Data collection and calculation must follow the significant digit guidelines outlined in Practice D6026. The standard emphasizes that observed and calculated values should adhere to industry standards for rounding and precision.
| 🟦 Standard | 📐 Title and Application |
|---|---|
| D4050 | Test Method for Withdrawal and Injection Well Tests – used for conducting the required tests. |
| D4106 | Practice for Determining Transmissivity and Storage Coefficient using Theis nonequilibrium method. |
| D6026 | Practice for Using Significant Digits in Geotechnical Data – governs data precision. |
📊 Interpreting Results and Limitations
The estimated transmissivity is derived from specific capacity data using a variation of the Theis nonequilibrium method. However, accuracy is contingent on how closely field conditions match the simplifying assumptions of the Theis model. Limitations include deviations in aquifer heterogeneity, boundary conditions, and well design. The standard cautions that this practice cannot replace professional expertise and must be applied with consideration of project-specific factors.
| 🎯 Limitation Factor | ⚡ Impact on Transmissivity Estimation |
|---|---|
| Field-Theis Correspondence | Poor correspondence leads to inaccurate estimates |
| Apparatus Capabilities | Scope is limited by the test equipment used |
| Significant Digit Practices | Must follow D6026 to ensure consistency |
💡 Tip: Always integrate professional judgment when applying this standard, as site-specific conditions may require adjustments to the procedure or interpretation.
⚠️ Warning: The accuracy of transmissivity estimates is highly dependent on how well field conditions match the simplifying assumptions of the Theis method. Deviations can lead to unreliable results.
❓ Frequently Asked Questions
🔍 What does this standard specifically address?
It addresses the procedure for determining specific capacity and estimating transmissivity at a control well through a specific capacity test.
💡 How is transmissivity estimated from specific capacity?
Transmissivity is estimated using a variation of the Theis nonequilibrium method, which requires specific capacity data from the control well.
⚡ What are the main limitations of this practice?
Limitations primarily relate to the correspondence between field conditions and the simplifying assumptions of the Theis method, as well as apparatus capabilities.
📌 Which ASTM standards are referenced?
Referenced standards include D4050 for well tests, D4106 for the Theis method, and D6026 for significant digit guidelines.