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Hydrogeologic Cross Sections
By John D. Barry
2018
Geologic Atlas of Wright CountyCounty Atlas Series C-30, Part B
Plate 9 of 9Hydrogeologic Cross Sections
D–D’ through G–G’
Minnesota Department of Natural ResourcesCounty Geologic Atlas Program mndnr.gov/groundwatermapping
To accompany the atlas Report and Plates 7–8.
Cross Section D–D′
Loam till is the dominant geologic material at the land surface except in three areas located in the west, central, and east portions of the cross section, where coarse-textured deposits allow recent tritium-age water to migrate from the surface to underlying shallow buried sand aquifers. Aquifers are connected at these locations, with few or no intervening till layers to impede vertical migration of water. Recharge along the rest of the cross section is more limited, as the loamy tills of the Heiberg Member (hbt) and Villard Member (nt) at the land surface have relatively low hydraulic conductivity. Vintage tritium-age water was present on the west side and central region at depths of approximately 100 to 150 feet below the land surface. Water collected from a buried sand aquifer (scs) near Rhoades Avenue NW had a calculated carbon-14 residence time of 3,000 years. Another sample from a buried sand aquifer (psu) collected east of Granite Lake had a calculated carbon-14 residence time of 2,000 years.
On the east side recent and mixed tritium-age signatures were found in buried sand aquifers and upper bedrock aquifers at depths of approximately 150 to 175 feet below the land surface. In general, vintage tritium-age water was present at depths greater than 200 feet below the land surface. Mixed tritium-age water was found roughly 350 feet below the land surface in the Buffalo area that is inconsistent with the tritium ages determined from surrounding wells; its result is 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 Albert and Beebe lakes and toward smaller streams.
Cross Section E–E′
Three areas of coarse-textured sediments near Kramer Ave SW, and County Highways 8 and 12, appear to allow recent tritium-age water to migrate from the surface to underlying shallow buried sand aquifers. Aquifers are connected in these locations, with little or no intervening till to impede vertical migration of water. Recharge and connectivity to the land surface along the rest of the cross section is more limited, as the loamy tills of the Heiberg Member (hbt) and Villard Member (nt) have relatively low hydraulic conductivity. Vintage tritium-age water was present in the west and central regions at depths of approximately 100 to 150 feet below the land surface. Water was collected from two vintage tritium-age wells near County Highway 7. The buried sand aquifer (cg1) in this location had a calculated carbon-14 residence time of 3,000 years and a well completed in the Mesoproterozoic bedrock aquifer (Mss) had a calculated carbon-14 residence time of 6,500 years.
On the east side mixed tritium-age groundwater was found in buried sand aquifers at depths ranging between 80 and 160 feet below the land surface. In general, vintage tritium-age water was present at depths greater than 200 feet below the land surface. Water collected west of Dean Lake from a well with vintage tritium age had a calculated carbon-14 residence time of 1,700 years.
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 Dean Lake and toward smaller streams.
Cross Section F–F′
Loam till is the dominant geologic material at the land surface along this cross section. However, in two small areas near County Highway 3 and State Highway 25, coarse textured deposits allow recent tritium age-water to migrate from the surface to underlying shallow buried sand aquifers. Near County Highway 3, aquifers are connected, with no intervening till to impede vertical migration of water. Recharge along the rest of the cross section is more limited, as the loamy tills of the Heiberg Member (hbt) and Villard Member (nt) at the land surface have relatively low hydraulic conductivity.
In general, vintage tritium-age water was present across the cross-section line below the Moland Member (mt) till at depths of approximately 100 to 150 feet below the land surface. Some exceptions occur: vintage tritium-age water was found above the mt till in the Howard Lake area and mixed tritium-age water was found below the mt till near Delano. Carbon-14 residence time was calculated from two wells: <100 years (recent) for the nts buried sand aquifer in the Howard Lake area, and <100 years (recent) for an Upper Tunnel City aquifer from the east side.
Groundwater flow depicted as equipotential lines is both vertically downward and east toward the regional groundwater discharge zone, the South Fork Crow River. Local groundwater flow is toward lakes such as Howard and Waverly lakes and toward smaller streams.
Cross Section G–G′
Loam till is the dominant geologic material at the land surface along this cross section. However, near the South Fork Crow River, recent tritium-age water can migrate from the surface to an underlying shallow buried aquifer. The aquifers are connected in this location, with no intervening till to impede vertical movement of water. Recharge along the rest of the cross section is more limited, as the loamy till of the Heiberg Member (hbt) and Villard Member (nt) at the land surface have relatively low hydraulic conductivity. No recent or mixed tritium-age water was sampled along this line. Vintage tritium-age water was present at depths of approximately 100 to 150 feet below the land surface. A buried sand aquifer (scs) sample near the west edge had a calculated carbon-14 residence time of 5,000 years, highlighting the limited recharge through the tills in the west portion of the county. Two vintage tritium-age wells west of Ann Lake were tested for carbon-14 analysis, resulting in 2,000 years for the buried sand aquifer (cg) and 19,000 years for the Mt. Simon aquifer.
Groundwater flow depicted as equipotential lines is both vertically downward and east toward the regional groundwater discharge zone, the South Fork Crow River. Local groundwater flow is toward lakes such as Ann Lake and toward smaller streams.
1020
900
1000920
980960
940920
hl
Mss
ms
ct1
_m
Mss
nts
hwtmlt sct
Ka
_sl
nt
_tc
ct1
hbt
hwt
ha
hs
scthwt
_tc
mt
mt
_w
nhs
Kd
nts
nt
hl
_w
pu
<ls
_e
pwt
scs
<mv
_e
cg1
_m
pu
8.3
17
14
30.2
38
9
11.6
5.8
3
768
370
247440
174
120
223
232
150
181
470
19,000
2000
5000
1050
1100
1000
950
900
850
800
750
700
650
600
550
500
450
400
350
300
1050
1100
1000
950
900
850
800
750
700
650
600
550
500
450
400
350
300
Ele
vatio
n (fe
et)
G’G
Coun
ty H
wy
3
Stat
e Hw
y 25
Sout
h Fo
rk C
row
Riv
er
Coun
ty H
wy
13
Ann
Lake
Coun
ty H
wy
30
Coun
ty H
wy
30
Emm
a La
ke
Coun
ty H
wy
8
1000
980
960
940
920
hbtms
nhs
ms
hwt
ct1
hwt
nts
nts
mt
scs
pu
_tc
mlt
zus
pu
_w
_w
<mv MssAgr
hbt
cg1
nts
sct
Ka
mt
nts
cg1hwt
nt
pu
mt
hl
hwt
mt
Kd
_tc
ct1
_e
_m
<ls
psu
cgct
nt
hs
mltmls
1050
1100
1000
950
900
850
800
750
700
650
600
550
500
450
400
350
300
1050
1100
1000
950
900
850
800
750
700
650
600
550
500
450
400
350
300
Ele
vatio
n (fe
et)
F’F
110
18.7
7.6*
14.7
Recent
Recent
5.8
10.7
8.9
9
17
36
6
29
6.510
8
9.3
31
2.06
1330
210
270 2991000
130
1000
390
330
284
110
250570
780
165
830640
470330
Stat
e Hw
y 25
Sout
h Fo
rk C
row
Riv
er
Coun
ty H
wy
31
Litt
le W
aver
ly L
ake
Sprin
g La
ke
How
ard
Lake
US
Hwy
12
Dagu
e Av
e SE
Dela
no
Coun
ty H
wy
3
Wav
erly
Lak
e1000
980960
940940
920
900
ct1
pu
sct
ct1
msmt
mt
<gu
_w
_m
mtmt
mt
hs
ctnhs
cg1
Mss
Agr
_tc
Kd
Ka
hbtnt
hwt
nt
nt
hs
nts
pu
mlt
scs
ntssct
mlt
nts
_e
ms
_e
nhsha
pu
hl
hwt
Agt
pu
<ls
_tc
_j_sl
hbt
mls
ct1
nts
cg1
nt
hbt
hwt
1050
1100
1000
950
900
850
800
750
700
650
600
550
500
450
400
350
300
1050
1100
1000
950
900
850
800
750
700
650
600
550
500
450
400
350
300
Ele
vatio
n (fe
et)
E’E
12
7.2
5.4* 1211.6
24.1
4
6.2
20
52
9.317
380
540
180174
168
144
305
380
250298
233204
3000
1700
6500
Stat
e Hw
y 55
Dean
Lak
e
Coun
ty H
wy
6
Coun
ty H
wy
12 Ham
lin A
ve S
E
Crow
Riv
er
Coka
to L
ake
Dem
psey
Ave
SW
Nor
th F
ork
Crow
Riv
er
Crow
Riv
er
Coun
ty H
wy
8
Coun
ty H
wy
7
Kram
er A
ve S
W
Aher
n Av
e SECo
unty
Hw
y 3
1000
980
960
940940
920
900
1000
zuszus
hbt
pu
nts
Agn
cg1
_m
pwt
<gu
sct
Agn
_m
prt
nt
nt
hs
hbtnt
sct
prs
mlt
_e
mt
Ka
ct
cg
_w
prt
nts
Ka
psu
hl
ct1
pwt
nt
ct1mls
hs
ms
ctms
pwt
A<d
mt
Mss
_m
hbt
cg1sct
hbt
nt
msnt
mtscs
nts
_tc
hs hwt
ct1
cg
mt
nhs
zus
nts
mlt
hwt
pupws
nhs11.4
21
7.4
8.3
9.8177*
14.9
15.13000
2000
12.9
8.7
8.1
16
11.1
49
7
330
480
223
243
110
195
120
440
102
420 274
130
202
100
3403.9
2.8
4.14.1
1050
1100
1000
1150
950
900
850
800
750
700
650
600
550
500
450
400
350
1050
1100
1000
1150
950
900
850
800
750
700
650
600
550
500
450
400
350
300
Ele
vatio
n (fe
et)
D’DCr
ow R
iver
Coun
ty H
wy
12
Crow
Riv
er
Rhoa
des A
ve N
W
Gran
ite L
ake
Coun
ty H
wy
3
Rock
Lak
e
Albe
rt L
ake
Coun
ty H
wy
6
Beeb
e La
ke
Coun
ty H
wy
7
Nor
th F
ork
Crow
Riv
er
Coun
ty H
wy
8
Buffa
lo
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.
The Minnesota DNR prohibits discrimination in its programs and services based on race, color, creed, religion, national origin, sex, public assistance status, age, sexual orientation, or disability. Persons with disabilities may request reasonable modifications to access or participate in DNR programs and services by contacting the DNR ADA Title II Coordinator at [email protected] or 651-259-6157. Discrimination inquiries should be sent to Minnesota DNR, 500 Lafayette Road, St. Paul, MN 55155-4049; or Office of Civil Rights, U.S. Department of the Interior, 1849 C Street NW, Washington, DC 20240.
© 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
LOCATION DIAGRAM
)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*
*Not all wells are displayed in cross section view due to the high density of wells.
D D’
Part B line of cross section shown on Plate 8
A A’
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
*aquitard
*aquitard
ha
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
Unnamed
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, Agr, Agt, A<d, <gu, <ls, <mv)
_j
_e
_m
_w
_tc
_sl
Kd
Ka
Mss
ct
hwt, mt
ct1, nt, prt
hbt, pwt, sct, mlt
hl
>60%
>50% and ≤60%
>40% and ≤50%
>30% and ≤40%
≤30%
CROSS SECTION EXPLANATION
Interpreted tritium age is indicated by background color
Interpreted tritium age is indicated by pattern color
hl*
hbt*
nhs, nts
nt*
ms
mt*
cg
ct*
cg1
ct1*
hs
hwt*
scs
sct*
mls
mlt*
prs
prt*
pws
pwt*
psu
pu
zus
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 ageDarker 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]).
7.2
29
5000
250
Enhanced-permeability zone
Groundwater moves from an overlying surficial aquifer to a buried aquifer.Groundwater moves from an overlying buried aquifer to an underlying buried aquifer.
Groundwater flowpath is unknown.
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
Chloride: if shown, concentration is ≥5 ppm.(* indicates naturally elevated values)
Arsenic: if shown, concentration is ≥2 ppb.
Manganese: if shown, concentration is ≥100 ppb.
Carbon-14 (14C): if shown, estimated groundwater residence time in years.
Groundwater flows laterally.
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