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900
860
1040
1060
1020
880
1000980
960 940
920mls
nls
mt
_tc
Mss
hbtnts
_e
prt
<gr
_w
nts
cg1nt
cg
pu
ms
<gr
pu_m
hwt
<gu
ms
_tc
nthl
_e
hbt
nhsnhs
ct1
ct1
ct1
mlt
ct
_sl
<dg
mlsmlt
_tc
ct1
<dg
ct
cg
prt
hwt
nts
mt
sct
Agn
nhs
mlt
ct
hl nt
psu
hanhs
cg1nts
hwt
ct1
hs
nts
<gu
ntsmt
ct1
mt
Mss
<gr
ms
_j
cg1
nts
sct ct1
_m
mt
zus
nts hbt
sct
_m
_m
nt
<gr
_w
8732
345.2*
5.8*
20.2
227.9
12
7
117
16.2 2413
510110
460
460
650
189540
690
540
360
139
560
810270
170
50034.9
1050
1100
1000
1200
1150
950
900
850
800
750
700
650
600
550
500
450
400
1050
1100
1000
950
900
850
800
750
700
650
600
550
500
450
400
350
300
Ele
vatio
n (fe
et)
C’
C
Coun
ty H
wy
5
Map
le L
ake
Lake
Fra
ncis
Gilc
hrist
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e
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an L
akeCo
unty
Hw
y 6
Stat
e Hw
y 25
Stat
e Hw
y 55
Coun
ty H
wy
2
Nor
th F
ork
Crow
Riv
er
Fost
er L
ake
Coun
ty H
wy
37
Stat
e Hw
y 10
1
I-94
Coun
ty H
wy
3
Moo
se L
ake
prtsct
cg1
mt
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hs
nt
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ms
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nt
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ct1
_e
mt
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ntsct
nts
wmt
pu
cg
wmtcg1
<gr
<gr
ha
ct
ctmt
_e
prs
ct1
hwt nts
Mss
Mss
mlt
prt
_wha
mlt
ct
ct1
prs
nts
cg1
hbt
Agn
sct
ct1
prssct
wmt
nt
Agn
hs
pu
cg wmt
pu
_tc
ct1
ct1
ms
cg1 ms
prt
_m
nt nt
<dg
ct
zus
prt
mt
ha
mt
<gr
ct
hwt
ha
Mss
mlt
Kd
sct hwt
_w
pwt
940
920
900
1060
860
1040
880
10201000 1000
980
960
5711.1
19.912.2
15.6
5.6*
6.1
6*
91
19.5
2618.4 6
7.1
10.3200
130
370
380320
940
186
610
680
300
730
1.879.2
1.78
9
4500
50004
2.6
2.3
1050
1100
1000
1150
950
900
850
800
750
700
650
600
550
500
450
400
1050
1100
1000
1150
950
900
850
800
750
700
650
600
550
500
450
400
350
300
Ele
vatio
n (fe
et)
B’B
Stat
e Hw
y 25
Coun
ty H
wy
39
Coun
ty H
wy
39
Miss
issip
pi R
iverBi
rch
Lake
Long
Lak
e
Coun
ty H
wy
2
Mon
ticello
Stat
e Hw
y 55
Clea
rwat
er L
akeCl
earw
ater
Riv
er
Miss
issip
pi R
iver
Stat
e Hw
y 24
Coun
ty H
wy
8
Miss
issip
pi R
iver
<dg
mt
Agn
ct1
<gd
zus
ct
Kd
sct ha
<gr
ct1
prs
wmt
nt
cg1
nts
hscghwt
nts
ct1
nt
puprt_mmlt
980 960940
9201000 59
19
7.5
75.9
6.2
29
228
312
250 410
180
232
100
3.4
1000
1800
3.1
2.7
3.9
1050
1000
950
900
850
800
750
700
650
600
1050
1000
950
900
850
800
750
700
650
600
550
500
Ele
vatio
n (fe
et)
A’A
Twin
Lak
e
Miss
issip
pi R
iver
I-94
Stat
e Hw
y24
Wie
gand
Lak
e
Coun
ty H
wy
8
Coun
ty H
wy
7
LOCATION DIAGRAM
1000
950
900
850
800
750
700
650
600
550
1050
1000
950
900
850
800
750
700
650
600
550
Ele
vatio
n (fe
et)
Mss
ct1
cg hlmt
psu
cg1
nt
prt
pu
Agn
Cmts
ct
Birch Lake
*aquitard
*aquitard
includes ha, wmt
Aquifers and aquitards grouped by stratigraphy
Quaternary unconsolidated sediment(see Figure 6 in the report for geologic unit correlation)
Quaternary aquitards
Grouped by texture ranging from highest to lowest sand content indicating relative hydraulic conductivity.
Surficial sand and gravel
Buried aquifers and aquitards
Geologic unit code Percent sand
Bedrock Dakota
Jordan
St. Lawrence Formation*
Upper Tunnel City
Wonewoc
Eau Claire Formation*
Mt. Simon
Mesoproterozoic (includes Hinckley, Fond du Lac, and Solor Church)
Precambrian crystalline bedrock (includes Agn, <dg, <gd, <gr, <gu)
_j
_e
_m
_w
_tc
_sl
Kd
Mss
ct
hwt, mt
ct1, nt, prt
hbt, pwt, sct, mlt
hl
>60%
>50% and ≤60%
>40% and ≤50%
>30% and ≤40%
≤30%
Groundwater conditions
Symbols and labels
Land or bedrock surface
General groundwater flow direction
Geologic contact
Approximate equipotential contour; contour interval 20 feet
900
Water table
Tritium age
Darker color in small vertical rectangle (well screen symbol) indicates tritium age of water sampled in well. Lighter color indicates interpreted age of water in aquifer.
Mixed: water is a mixture of recent and vintage waters (greater than 1 TU to less than 8 TU).
Well not sampled for tritium.
Vintage: water entered the ground before 1953 (less than or equal to 1 TU).
Recent: water entered the ground since about 1953 (8 to 15 tritium units [TU]).
CROSS SECTION EXPLANATION
Interpreted tritium age is indicated by background color
Interpreted tritium age is indicated by pattern color
Chloride: if shown, concentration is ≥5 ppm.(* indicates naturally elevated values)
32
Nitrate: if shown, concentration is ≥1 ppm.9.2
Arsenic: if shown, concentration is ≥2 ppb.24
Manganese: if shown, concentration is ≥100 ppb.
Carbon-14 (14C): if shown, estimated groundwater residence time in years.
5000
180
Enhanced-permeability zone
hl*
hbt*
nhs, nts
nt*
ms
mt*
cg
ct*
cg1
ct1*
hs
hwt*
scs
sct*
mls
mlt*
prs
prt*
pwt*
psu
pu
zus
Groundwater moves from an overlying surficial aquifer to a buried aquifer.
Tritium concentrations may be artificially elevated by high capacity pumping.
Groundwater moves from an overlying buried aquifer to an underlying buried aquifer.
Water from the surface moves through a thin layer of overlying fine-grained material to an underlying aquifer.
Groundwater discharges to a surface-water body.
Direction of fault movement, arrows indicate relative movement
Groundwater flowpath is unknown.
Groundwater flows laterally.
)101
)24
)55
)25
)25
)55
94
12
94
Howard Lake
Buffalo
Maple Lake
Annandale
South Haven
Rockford
WaverlyCokato
Montrose
Delano
Albertville
Monticello
Clearwater
45°
94°
94°15'
93°45'
45°15'
B’
A A’
B
C
D
E
G
F
D’
E’
F’
G’
C’
C’C
D’D
E’E
A
B
A’
B’
Symbols
Part B line of cross section shown on this plate
Well used to generate cross section*
A A’
Part B line of cross section shown on Plate 9
D D’
Part A line of cross sectionA A’
N
1 0 1 2 3 4
SCALE 1:300 000
1 0 1 2 4 5 6 7 83 9 KILOMETERS
5 MILES
*Not all wells are displayed in cross section view due to the high density of wells.
1 0 1 2 3 4 5 MILES
1 0 1 2 4 5 6 7 83 9 KILOMETERS
SCALE 1:100 000VERTICAL EXAGGERATION X 50
Hydrogeologic Cross Sections
By John D. Barry
2018
Geologic Atlas of Wright CountyCounty Atlas Series C-30, Part B
Plate 8 of 9Hydrogeologic Cross Sections
A–A’ through C–C’
Minnesota Department of Natural ResourcesCounty Geologic Atlas Program mndnr.gov/groundwatermapping
To accompany the atlas Report and Plates 7 and 9.
Cross Section A–A′
Three areas of coarse-textured sediments (sand and gravel) allow recent tritium-age water to migrate from the land surface to underlying shallow buried sand aquifers. In these areas, elevated chloride and nitrate were present. Elsewhere, loam till (sand, silt, and clay) lessens groundwater recharge and offers a level of protection to underlying aquifers. Aquifers deeper than approximately 100 feet below the land surface had vintage tritium-age signatures. Water collected from two wells in buried sand aquifers had calculated carbon-14 residence times of 1,000 (scs) and 1,800 (zus) years. Groundwater flow, depicted as equipotential lines, is both vertically downward and east toward the regional groundwater discharge zone, the Mississippi River. Local groundwater flow is toward lakes such as Wiegand Lake and Twin Lake and toward small streams.
Cross Section B–B′
Many aquifers are connected along this cross section with no intervening till to impede vertical migration of water. The west and east sides of the cross section have a prevalence of coarse-textured sediments at the land surface that allow recent tritium-age water to migrate from the surface to underlying shallow buried sand aquifers. In the west portion, mixed tritium-age water was found at a depth of approximately 80 feet below the land surface. Vintage tritium-age water was sampled from two wells in Cretaceous deposits (Kd) that are roughly 200 to 250 feet below the land surface. The water from the well near County Highway 2 had a calculated carbon-14 residence time of 5,000 years.
In the central portion of the cross section, more permeable till units and areas of overlapping aquifers allow recent and mixed tritium-age water to migrate to depths of approximately 100 feet below the land surface.
On the east side of the cross section, mixed tritium-age signatures were present to depths 150 to 200 feet below the land surface. This is likely due to coarse sand deposits at the land surface and the higher relative hydraulic conductivity of the intervening till of the Cromwell Formation (ct). In this area recent and mixed tritium-age water was present in aquifers above the Mt. Simon. In the Mt. Simon, vintage tritium-age water had a calculated carbon-14 residence time of 4,500 years. Near Monticello, high-volume groundwater appropriation appears to have brought mixed tritium-age water to depths greater than would be expected without pumping.
Groundwater flow depicted as equipotential lines is both vertically downward and east toward the regional groundwater discharge zone, the Mississippi River. Local groundwater flow is toward lakes such as Clearwater and Long lakes and toward smaller rivers and streams such as the Clearwater River.
Cross Section C–C′
Loam till is the dominant geologic material at the land surface along this cross section. However, near Moose Lake and County Highway 2 coarse-textured deposits allow recent tritium-age water to migrate from the surface to underlying shallow buried sand aquifers. In these locations, aquifers are connected, or have few intervening tills to impede vertical migration of water.
Recharge along the rest of the cross section is more limited, as the loamy till of the Heiberg Member (hbt) has relatively low hydraulic conductivity. Vintage tritium-age water was present on the west side of the line at depths exceeding 150 feet. Water collected from a buried sand aquifer (scs) near Maple Lake had a calculated carbon-14 residence time of 500 years.
East of I-94, recent and mixed tritium-age signatures were common in buried sand aquifers at depths of approximately 150 to 200 feet below the land surface. In general, vintage tritium-age water was present in the bedrock aquifers. Recent tritium-age water was found at depth in a well west of Foster Lake that was inconsistent with the tritium ages determined from surrounding wells; the reason for its occurrence was unclear.
Groundwater flow depicted as equipotential lines is both vertically downward and east toward the regional groundwater discharge zone, the North Fork Crow River. Local groundwater flow is toward lakes such as Maple and Pelican lakes and toward smaller rivers and streams such as the North Fork Crow River.
Note about the vertical exaggerationThe cross sections use a vertical exaggeration 50 times greater than the horizontal scale. The geologic units are otherwise difficult to see at a one-to-one scale.
For comparison, this inset depicts a portion of cross section B–B′ with no vertical exaggeration to illustrate the true thicknesses of the units. The inset location is indicated by the red rectangle near Birch Lake.
This map was compiled and generated in a geographic information system. Digital data products are available from the DNR County Geologic Atlas Program at mndnr.gov/groundwatermapping.
This map was prepared from publicly available information. Every reasonable effort has been made to ensure the accuracy of the factual data on which this map interpretation is based. However, the DNR does not warrant the accuracy, completeness, or any implied uses of these data. Users may wish to verify critical information. Sources include both the references in the report and information on file in the offices of the Minnesota Geological Survey and the DNR. Every effort has been made to ensure the interpretation shown conforms to sound geologic and cartographic principles. This map should not be used to establish legal title, boundaries, or locations of improvements.
Base modified from Minnesota Geological Survey, Wright County Geologic Atlas, Part A, 2013.
Universal Transverse Mercator projection, zone 15N, North American Datum of 1983. North American Vertical Datum of 1988.
500 Lafayette Road St. Paul, MN 55155-4025 888-646-6367 or 651-296-6157 mndnr.gov
This information is available in alternative format on request.
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© 2018, State of Minnesota, Department of Natural Resources and the Regents of the University of Minnesota
Prepared and published with the support of the Minnesota Environment and Natural Resources Trust Fund and the Clean Water, Land and Legacy Amendment