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Aquifer Yield Calculator

Aquifer Yield

Calculate the sustainable yield of an aquifer using transmissivity, storativity, and pumping test data for water supply planning.

Formula

Q = (4 x pi x T x Drawdown) / W(u) (Theis Equation); u = r^2 x S / (4 x T x t); W(u) = -0.5772 - ln(u) (approximation); Specific Capacity = Q / Drawdown; Hydraulic Conductivity = T / Aquifer Thickness

Frequently Asked Questions

What is transmissivity?
Transmissivity is the rate at which water flows through a unit width of aquifer for a unit hydraulic gradient. It equals hydraulic conductivity times aquifer thickness and is measured in m2/day. Higher values mean more productive aquifers.
What is storativity?
Storativity (storage coefficient) is the volume of water released per unit area per unit decline in head. Confined aquifers have very low storativity (0.0001-0.001), while unconfined aquifers have higher values (0.01-0.3).
How do you determine sustainable yield?
Sustainable yield is determined through pumping tests, aquifer analysis, and long-term water balance studies. It must account for recharge rates, neighboring well interference, and environmental water needs.

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