The storage coefficient and transmissivity are calculated using which equation?

The storage coefficient and transmissivity are calculated using which equation?

• A. Bernoulli equation
• B. Navier-Stokes equation
• C. Theis equation
• D. Darcy's law

Answer: (C)

In pumping tests for a confined aquifer, the parameters storage coefficient and transmissivity appear in the Theis solution, which is the standard way to describe transient drawdown caused by pumping. The drawdown at a distance r and time t is given by s(r,t) = (Q / (4π T)) W(u), where u = r^2 S / (4 T t) and W is the well function (related to the exponential integral). This formulation comes from combining Darcy’s law with conservation of mass for a homogeneous, confined aquifer and explicitly uses S and T to characterize how much water is stored and how quickly it can move. Theis is the go-to equation for interpreting pumping tests and estimating S and T, whereas the other equations describe energy balance, general fluid dynamics, or steady-state flow and don’t directly provide the transient drawdown relationship used to extract these aquifer properties.

In pumping tests for a confined aquifer, the parameters storage coefficient and transmissivity appear in the Theis solution, which is the standard way to describe transient drawdown caused by pumping. The drawdown at a distance r and time t is given by s(r,t) = (Q / (4π T)) W(u), where u = r^2 S / (4 T t) and W is the well function (related to the exponential integral). This formulation comes from combining Darcy’s law with conservation of mass for a homogeneous, confined aquifer and explicitly uses S and T to characterize how much water is stored and how quickly it can move. Theis is the go-to equation for interpreting pumping tests and estimating S and T, whereas the other equations describe energy balance, general fluid dynamics, or steady-state flow and don’t directly provide the transient drawdown relationship used to extract these aquifer properties.