A well pump test is set up as shown in Figure $1$ with the first observation well located at $50$ feet $(r_1)$ and the second well at $100$ feet $(r_2)$ from the pumping well. Prior to the test, the static water level in the two observation wells was measured at $6ft$ below ground surface $($BGS$).$ The pump will reach steady state flow at $1000ga\frac{l}{h}$our at which point readings for the two observation wells will be $16ft$ BGS and $12ftBGS,$ respectively. The soil is supposed to be mostly fine sand and silt.

a$.$ Calculate the average permeability of the soil assuming the impervious layer is $25$ feet BGS$.$

b$.$ Calculate the average permeability of the soil assuming the impervious layer is $100$ feet BGS$.$

c$.$ Use the soil$-$permeability tables in the textbook, is your calculated permeability likely correct?

A well, $0\mathrm{.}1m$ radius, is part of a wellpoint network to keep an excavation dry $($Figure $2).$ The groundwater at the far edge of the excavation must be $0\mathrm{.}5m$ below the base.

a$.$ Calculate the radius of influence. $($Note: the answer given in the "Answers to Selected Exercises" is wrong for the original problem, so don't trust it$.)$

b$.$ Calculate the maximum drawdown.

c$.$ Plot the drawdown curve $(5$ or $10$ points, to scale, on engineering paper $-$ to go past both edges of the excavation $-$ would be sufficient$).$