A well is pumped at Q = 300 m3 /hr in a confined aquifer. The aquifer transmissivity is 25 m2 /hr and the storage coefficient is 2.5x10-4 . Calculate the drawdown at a distance …

Question

asked Jul 17, 2020 216k views

1 Answer

Ray Suelzer · Answer 1 · 2020-07-23T10:30:43+0000

Answer:

(a). The draw-down at a distance 200 m from the well after pumping for 50 hr is 5.383 m.

(b). The draw-down at a distance 200 m from the well after pumping for 50 hr is 6.707 m.

Step-by-step explanation:

Given that,

Energy
$Q=300\ m^3/hr$

Transmissivity
$T = 25\ m^2/hr$

Storage coefficient
S=2.5*10^(-4)

Distance r= 200 m

We need to calculate the draw-down at a distance 200 m from the well after pumping for 50 hr

Using formula of draw-down

$s= (Q)/(4\pi T)(-0.5772-ln(r^2S)/(4tT))$

Put the value into the formula

$s=(300)/(4\pi*25)(-0.5772-ln((200)^2*2.5*10^(-4))/(4*25*50))$

$s=5.383\ m$

We need to calculate the draw-down at a distance 200 m from the well after pumping for 200 hr

Using formula of draw-down

$s= (Q)/(4\pi T)(-0.5772-ln(r^2S)/(4tT))$

Put the value into the formula

$s=(300)/(4\pi*25)(-0.5772-ln((200)^2*2.5*10^(-4))/(4*25*200))$

$s=6.707\ m$

Hence, (a). The draw-down at a distance 200 m from the well after pumping for 50 hr is 5.383 m.

(b). The draw-down at a distance 200 m from the well after pumping for 200 hr is 6.707 m.