A strainer-type well that penetrates three pervious aquifer layers separated by three impervious aquicludes will draw water from which strata?

Introduction / Context:
Strainer (screened) wells are designed to admit groundwater selectively from pervious zones while excluding fine materials from surrounding formations. When multiple aquifer layers are present, screens can be placed to tap each layer separated by aquicludes.

Given Data / Assumptions:

• Three distinct pervious layers separated by impervious aquicludes.
• Strainers (screens) are installed opposite each pervious layer.
• Pumping induces radial flow into the screened intervals.

Concept / Approach:
Each screened interval hydraulically communicates with its adjacent permeable stratum. The total discharge is the sum of contributions from all open intervals, governed by transmissivity and drawdown distribution. Aquicludes prevent vertical leakage between pervious beds except through the wellbore itself at screened sections.

Step-by-Step Solution:

Verification / Alternative check:
Multi-layer well analysis (Jacob, Hantush) allocates contributions per layer based on transmissivity and storativity; field logs confirm inflow with spinner or heat-pulse flowmeter surveys.

Why Other Options Are Wrong:
Limiting inflow to only one layer ignores purpose of multiple screens; claiming “none” contradicts the defined design.

Common Pitfalls:
Screening continuously across aquicludes (not permitted); neglecting sand control and proper gravel packing leading to fines intrusion.

Final Answer:
All of the pervious layers (through their respective strainers).