NAME
GW Engineering EXAM I FALL 2010
PROBLEM #4 - 30
points
Vq
USE UNITS of METERS SECONDS and GRAMS
The confined aquifer illustrated in PLAN VIEW below is a uniform thickness of {3 meters.
It is underlain by low permeability bedrock and overlain by low permeability ctay.
Both Mystic and Caravan lakes fully penetrate the thickness of the aquifer which has a vertical
outcrop on the side of each lake (see cross-section view).
Hydraulic Gonductivity of the aquifer is 5.3 cm/sec and its specific yield is 0.23.
ANSWER THE QUESTIONS ON THE FOLLOWING PAGE, SHOW YOUR WORK
Stippled area is
confined aquifer
note outcrop of
aquifer at edge of
each lake
PLAN
VIEW
Caravan Lake
elevation
39 meters
ng
*+
1000m
\dir= ll
4o
l]=
Nh = JD, =3,fu36m
Gross-section
Not to Scale
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KE4
NAME
GW Engineering EXAM I FALL 2010
PROVIDE CALCULATIONS AND ANSWERS TO PROBLEM 4 HERE
USE UNITS of METERS SECONPS and GRAMS
4a) Draw a PLAN VIEW flow net ON THE PLAN VIEW ON THE PREVIOUS PAGE and label the
equipotential lines
gd.4' grrytcP t*s F"$
4b) The ground
elevationg+te-fb8an+hat
*
is the depth to water in the confined aquifer?
h*r =Qlrl5Y:)
&e$h &a LuahqiL B3;eq,qt \ff-
ss*
*
detected the bottom of the aquifer at 50m below grou
4c) The well at tne
is the pressure at the bottom of the aquifer?
€\e,v bo{t**
r
B3;5%=
.surface. What
33*
hp = h- *hg = 6{,{5t^*33r"
31,{5 r.n;
4d) Cqnsider a drop of water in the confined aquifer that passes through the x,y location of the
How many DAYS does it take that drop to travel from Mystic Lake to Caravan lake?
*.
SDC{} vn
\ im?. * i!r-",xlr+oe* r!tl*
Vs\nei%
flt
0,053o,.' El.n
S
r
?,THt$kg'*rs
-.
foosrn
r',3i,4**1p-
0-t 3
4e) What is the volumetric flow rate from the confined aquifer to Caravan Lake?
A * K*U$,bLl
z
.\r-'Pag
0rO5'$r^ 40*
5
!r
lI
3en
:
(t)
tf
's"*
s
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