Cone of Depression – determini
ng the maximum pumping rate fo
r a specified draw down.
(+20)
A consulting company decides to u
se Pump & Treat to remove the
TCE plume from the aquifer. For an
unconfined aquifer such as this, t
here is a possibility that dr
awdown during the Pump & Treat operation will
lower the water table to the
bottom of the well and that the wa
ter will stop flowing (thi
s is bad). Suppose a 6
inch diameter well is installed
which fully penetrates the 15-m
thick aquifer which has a hydraulic
conductivity of 0.001 m/s. Deter
mine the maximum pumping rate
(in gallons per minute, gpm) that can be
sustained indefinitely if the dr
awdown at an observation well 5
00 m from the pumped well is 12 m and the
drawdown at the pumped well is
limited by the depth of the aqui
fer and the height of the submersible pump,
which you may estimate at 0.3 m
(i.e., drawdown in the pumping
well may not exceed 14.7 m).
Answer: Q = 50.5 gpm.
