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Two Example Ground Water
Mounding Situations
John L. Nieber
Department of Biosystems and Agricultural Engineering
University of Minnesota
John L. Nieber
Biosystems and Ag. Eng.
Feb. 21, 2006
GW Mounding Forum
Ground Water Mounding
Beneath a Stormwater Basin
• Study conducted in Washington Co. by
Emmons & Olivier Associates
• Results presented here are from a
report to the MPCA and also from the
M.S. thesis (May 2005) of Jennifer
Olson.
John L. Nieber
Biosystems and Ag. Eng.
Feb. 21, 2006
GW Mounding Forum
John L. Nieber
Biosystems and Ag. Eng.
Feb. 21, 2006
GW Mounding Forum
CD-P85
930
920
960
950 950
970 Dale Road
95
890
0 93
• Natural
0
0
87
89
0
990
9 60
920
950
930
930
9 70
94
910
0
940
940
infiltration
10 30
basin
9 20
880
900
Infiltration Basin CD-P85
9 60
• 30 acres in
0
9 30
87 0
91
910
10 20
MW-2 #
S
MW-1
extent
900
#
S
10 00
0
940
• 29 feet deep
93
Pump Station
910
#
MW-4
S
94
91
MW-5 #
S
10
0
0
MW-3s; MW-3d
2
#
#
S
S
• Outwash
0
9 60
900
910
9 10
material
100
Woodbury Drive
9 30
0 9 40
90
0
96 930
0 0
94
940
8 90
890
• 7 wells
9 50
970
920
9 80 9 30
0
92
M
9 20
89
• Pump station
0
il
900
i
9 10
ta
930
ry
91
0
R
oa
links CD-P85
880
910
d
9 20
with City
9 00
97 0
0 91
0
89
91
stormwater
910
0
940 91 0
92
0
890 890
0
90
9 30
system
950
#
S
MW-3
9 20
910
9 10
0
91
910
900
John L. Nieber
CD- P85 E and 90 0
Biosystems lev ationAg.FtEng.
S Monitoring Wells
# 1000 0 1000 Fe et
Feb. 21, 2006
GW Mounding Forum
X-section through CD-P85
John L. Nieber
Biosystems and Ag. Eng.
Feb. 21, 2006
GW Mounding Forum
John L. Nieber
Biosystems and Ag. Eng.
Feb. 21, 2006
GW Mounding Forum
John L. Nieber
Biosystems and Ag. Eng.
Feb. 21, 2006 Sample infiltration curves for CD-P85
GW Mounding Forum
Water levels during 2002 in CD-P85
914
911
Drawdown 5,
August Event
908
905
Elevation [ft above MSL]
Drawdown 3,
902 July Event
899
896
893
890
887
884
13-Jun-02 8-Jul-02 2-Aug-02 27-Aug-02 21-Sep-02 16-Oct-02 10-Nov-02
Time [day/month/year]
John L. Nieber
Biosystems and Ag. Eng.
Feb. 21, 2006
GW Mounding Forum
Water levels in monitoring wells near CD-P85
Note the two scales for water levels
MW-3d MW-3s MW-4 MW-5 Bottom of Basin Surface Water
920 915
Drawdown 5
Drawdown 3 August Event
910
July Event 910
Surface Water Elevation [ft above MSL]
Ground Water Elevation [ft above MSL]
900
905
890
880 900
870 895
860
890
850
885
840
830 880
18-Jun-02 3-Jul-02 18-Jul-02 2-Aug-02 17-Aug-02 1-Sep-02 16-Sep-02
John L. Nieber
Biosystems and Ag. Eng. Time [day/month/year]
Feb. 21, 2006
GW Mounding Forum
Models Used for Simulations
• Hantush mounding model – simple analytical model,
most common ground water mounding equation
• Multi Layer Analytic Element Model (MLAEM) –
has been used at this site in past, regional flow
model in TCMA
• FEMWATER – unsaturated/saturated flow model,
recommended in literature for complex systems
John L. Nieber
Biosystems and Ag. Eng.
Feb. 21, 2006
GW Mounding Forum
Model Input
• Identical parameters used when applicable
• Measured parameters
– Recharge area, recharge rate, duration (transient vs.
steady state models), depth to water table, saturated
thickness, initial ground water elevation, bedrock
elevation, nearby lake elevations
• Literature value (unknown) parameters
– Saturated hydraulic conductivity (calibrated model,
slug test)
– Porosity (effective and fillable)
– Unsaturated flow characteristics
• Used first dataset (July 2002) to determine
unknown parameters
John L. Nieber
Biosystems and Ag. Eng.
Feb. 21, 2006
GW Mounding Forum
Model Input
(July event)
265.18
265.18
Bailey Lake
265.18
# Constant Head Boundary
265.18
Dale Road
264.56 #
266.850 # 265.180
264.56 264.56 Bailey Lake
# Constant Head Boundary
South Bailey Lake
264.56
#
264.56 265.180
Dale Road
0.28 #
264.560
CD-P85 0.28 #
0.28 Constant Flux Boundary
South Bailey Lake
Woodbury Drive
Woodbury Drive
#
# 264.560
266.850
# Constant Head Boundary
M
il
iit
a
a
ry
CD-P85
y
#
264.850
R
R
oa
#
d
d
#
Constant Flux Boundary
Gables Lake
Woodbury Drive
259.08 #
259.08
Shepard's Pond Constant Head Boundary
M
M
iil
it
t a
ry
M LAE M In pu t
y
#
264.850
R
C ons tan t H e ad N o des w ith E lev a ti on (m eters ) a nd 400 0 400 Meter s
o
r
a
a
d
C ons tan t F lu x N ode s w i th F l ow R ate (m e ters pe r da y)
#
M ode l Po lyg on
264.850
# Gables Lake
259.080
#
259.080
Shepard's Pond
John L. Nieber
#
#
264.850
264.850
Biosystems and Ag. Eng.
Feb. 21, 2006
FE M W AT E R In put
# C ons tan t H e ad N o des w ith E lev a ti on (m eters ) 300 0 300 Meter s
GW Mounding Forum
M ode l Bo und ary
M es h
265.18
265.18
Bailey Lake
265
265.18
# Constant Head Boundary
MLAEM
Dale Road
265.18
264.56
264.56 264.56
# Constant Head Boundary
South Bailey Lake
264.56 264
266 264.56
0.28
CD-P85 #
Constant Flux Boundary
Woodbury Drive
263
M
iil
iit
a
a
262
r
ry
R
R
oa
oa
d
d
Gables Lake
259.08 #
259.08
Shepard's Pond Constant Head Boundary
John L. NieberIn pu t
M LAE M
C ons tan t Eng.
Biosystems r and Ag.H e ad N o des w ith E lev a ti on (m eters ) a nd 400 0 400 Meter s
Feb. 21, 2006ode l Po lyg on
C ons tan t F lu x N ode s w i th F l ow R ate (m e ters pe r da y)
M
Forum
GW Mounding Gro un d W a ter C o ntour ( 0.5 m e te r inter v al)
Hantush Equation
John L. Nieber
Biosystems and Ag. Eng.
Feb. 21, 2006
GW Mounding Forum
Hantush
John L. Nieber
Biosystems and Ag. Eng.
Feb. 21, 2006
GW Mounding Forum
266.850 # # 265.180
Bailey Lake
265.5
#
265.180
FEMWATER
266 Dale Road
#
264.560
265.5 South Bailey Lake
#
#
264.560
266.850
# Constant Head Boundary
#
264.850
CD-P85
#
265.5 Constant Flux Boundary
Woodbury Drive
265
M
M
ill
iit
a
a
ry
y
#
264.850
R
R
o
a
d
#
264.850
Gables Lake
264.5 #
259.080
#
259.080
Shepard's Pond #
264.850
#
264.850
John L. Nieber
C ons tan t Eng.
Biosystems #and Ag.H e ad N o des w ith E lev a ti on (m eters ) 300 0 300 Meter s
Feb. 21, 2006es h
M ode l Bo und ary
M
Forum
GW Mounding Gro un d W a ter C o ntour ( 0.5 m e te rs inter v al)
Initial Model Result Comparison
Surface Water Level within Basin
6.00
Measured Water Elevation
Hantush Modeled Points
5.00
MLAEM Modeled Points
FEMWATER Modeled Points
Mound Height [meter]
4.00
MW-4
MW-5
3.00
2.00
1.00
MW-3s
MW-3d
0.00
0 50 100 150 200 250 300 350 400 450 500
John L. Nieber Distance from Center [meter]
Biosystems and Ag. Eng.
Feb. 21, 2006
GW Mounding Forum
Model Selection
• Sum of square differences
• MLAEM model – closest to observed
values
– Unable to calibrate porosity and Ksat to
desired accuracy – steady state
• Hantush model – second best
– Calibration parameters include Ksat and
porosity – most variable and unknown
parameters
John L. Nieber
Biosystems and Ag. Eng.
Feb. 21, 2006
GW Mounding Forum
Calibrated Model
(Hantush)
Observed Values Calibrated Model Results
7
6 Center of Basin
5
Mound Height [meters]
MW-5
4
MW-4
3 MW-5 MW-4
2
MW-3s
Mw-3d
1
MW-3s Mw-3d
0
0.0 50.0 100.0 150.0 200.0 250.0 300.0 350.0 400.0 450.0
Distance from Center [meters]
John L. Nieber
Biosystems and Ag. Eng.
Feb. 21, 2006
GW Mounding Forum
Some WSAS Mounding Effects
Analysis performed with COMSOL MP3.2
Finite Element Solution of the Richards Equation
John L. Nieber
Biosystems and Ag. Eng.
Feb. 21, 2006
GW Mounding Forum
Vertical section showing five leach
trenches and a perching layer
John L. Nieber
Biosystems and Ag. Eng.
Feb. 21, 2006
GW Mounding Forum
120 gallons/day/foot; Ks = 2.8 feet/day
John L. Nieber
K = 0.28 feet/day
Biosystems and Ag. Eng.
perch layer
Feb. 21, 2006
GW Mounding Forum
120 gallons/day/foot; Ks = 2.8 feet/day
John L. Nieber
K = 0.28 feet/day
Biosystems and Ag. Eng.
perch layer
Feb. 21, 2006
GW Mounding Forum
18 gallons/day/foot; Ks = 2.8 feet/day
John L. Nieber
K = 0.028 feet/day
Biosystems and Ag. Eng.
perch layer
Feb. 21, 2006
GW Mounding Forum
7 gallons/day/foot; Ks = 2.8 feet/day
John L. Nieber
K = 0.0028 feet/day
Biosystems and Ag. Eng.
perch layer
Feb. 21, 2006
GW Mounding Forum
246 gallons/day/foot; Ks = 2.8 feet/day
John L. Nieber
K = 2.8 feet/day
Biosystems and Ag. Eng.
perch layer
Feb. 21, 2006
GW Mounding Forum
175 gallons/day/foot; Ks = 2.8 feet/day
John L. Nieber
K = 0.28 feet/day
Biosystems and Ag. Eng.
ellipses
Feb. 21, 2006
GW Mounding Forum
Summary
Perm of low perm Infiltration
layer (ft/day) (gal/ft/day)
0.28 120
0.028 18
0.0028 7
2.8 246
ellipses 175
Low perm layers do not need
to be continuous to affect
septic infiltration rate
John L. Nieber
Biosystems and Ag. Eng.
Feb. 21, 2006
GW Mounding Forum
