Aquifer flow terminology: which statement is incorrect regarding permeability, transmissibility, Darcy’s law, and terminology origin?
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ACoefficient of permeability: discharge per unit area under unit hydraulic gradient
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BCoefficient of transmissibility: discharge through a vertical strip of unit width and full saturated depth under unit gradient
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CFlow through aquifers is governed by Darcy’s law in laminar range
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DTerm “transmissibility” was introduced by Meinzer
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ENone of these statements is incorrect
Answer
Correct Answer: None of these statements is incorrect
Explanation
Introduction / Context:Clear understanding of aquifer parameters underpins groundwater hydraulics, well design, and pumping-test interpretation. This item checks precise definitions and historical terminology in hydrogeology.
Given Data / Assumptions:
- Laminar flow conditions typical of many porous aquifers.
- Standard hydrogeologic definitions are used.
- Vertical strip definition is a classical way to visualize transmissibility.
Concept / Approach:Permeability (hydraulic conductivity, K): discharge per unit area per unit hydraulic gradient (dimensions L/T).Transmissibility (often transmissivity, T): K * b, where b is aquifer saturated thickness; dimensions L^2/T; equivalently, discharge per unit width across the full saturated thickness under unit gradient.Darcy’s law governs laminar flow in porous media: q = −K (dh/dl) A.Terminology: Meinzer is historically credited with introducing 'transmissibility/transmissivity' in U.S. hydrogeology.Given these, all listed statements are correct; hence the only correct choice for “incorrect statement” is 'None of these statements is incorrect'.
Step-by-Step Solution:
1) Check each definition against standard texts.2) Confirm T = Kb and its interpretation as unit-width discharge under unit gradient.3) Confirm Darcy’s law applicability.4) Recognize Meinzer’s terminology contribution.5) Conclude none are incorrect.Verification / Alternative check:Groundwater hydraulics references (e.g., pumping-test theory) align with these definitions and attributions.
Why Other Options Are Wrong:
- Each individual statement (a)–(d) is correct; picking any would incorrectly label a true statement as false.
Common Pitfalls:
- Confusing permeability (K) with intrinsic permeability (k) and fluid-property effects.
- Mixing units of T (L^2/T) and K (L/T).
- Overextending Darcy’s law into turbulent regimes (e.g., coarse gravels).
Final Answer:None of these statements is incorrect