Ground-Water Open-File Report 19, Sheet 2
November, 2007
Montana Bureau of Mines and Geology
A Department of Montana Tech of The University of Montana
Map B. Locations of
wells <100 ft deep and
within 1 mile of
major streams
Map A. Hydrologic features
and the number of wells
per section <100 ft deep
As of January 2005
rt
No
Map C. Locations of wells
between 100 and 300
ft deep and within 1
mile of major streams
Map D. Locations of wells
>300 ft deep and
within 1 mile of
major streams
6,011 wells
2,167 wells
or k
hF
4,314 wells
t
Fla
R.
lw a
.
dR
h
efis
hea
it
Wh
Stil
Miles
5 10
0
ter
LAKE
MCDONALD
R.
West Glacier
0
20
Miles
5 10
20
0
SCALE 1:792,000
SCALE 1:792,000
Miles
5 10
20
0
SCALE 1:792,000
Miles
5 10
20
SCALE 1:792,000
!
Whitefish
WHITEFISH
!LAKE
dd
Mi
Columbia Falls
!
t
Fla
ad R
.
Flath
e
LITTLE
BITTERROOT
LAKE
HUNGRY
HORSE
RES.
Marion
!
.
dR
!
he a
Kalispell
.
.
.
.
or k
le F
ASHLEY
LAKE
Somers
!
!
or k
th F
F la
LAKE
a
the
.
dR
Swan R.
Polson
!
Sou
Swan Lake
SWAN
LAKE
FLATHEAD
!
B
tle
Lit
Hot Springs
Pablo
!
itte
ad R
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!
ot
Flath
e
rro
Ronan
!
R.
Charlo
!
Flat
h
e ad
R.
Jo
c
Cities and towns
Study area
County boundaries
Streams
Dixon
!
!
St Ignatiuss
!
ko
R.
Arlee
!
Lakes
Number of
well records
per section:
NO
OU TLINE
0
1 - 10
11 - 30
31 - 50
51 - 80
81 - 160
Ground-Water Resource Development in the Flathead Lake Ground-Water
Characterization Area, Flathead, Lake, Missoula, and Sanders Counties,
Montana
By Kirk B. Waren and Thomas W. Patton
Map E. Irrigation
wells within 1 mile
of major streams
Sheet 2. The number of wells per section that are <100 ft deep and wells
within 1 mile of major streams.
Legend: Maps B through F
Generalized geology
Individual wells
by total depth:
Alluvium along major streams
0 - 100 ft
Glacial deposits
Tertiary basin fill
Between 100 and 300 ft
Bedrock
Map F. Commercial,
industrial, and
public water
supply wells
within 1 mile of
major streams
247 wells
0
20
0
300 - 2,000 ft
5
Miles
10
(Acre-ft per year, Flathead and Lake Counties)
Source: Cannon and Johnson, 2004
1%
1%
1%
2%
Commercial
5%
400
Irrigation
Irrigation
2,800
Public water wupply
20
Public water
supply
Industrial
SCALE: 1:1,000,000
Explanation
Self-supplied domestic
9,100
Stockwater
The number of wells per section shown in Map A is for January 1, 2005, so the data are comparable to Maps E and H
on Sheet 1. The data for Maps B through F were retrieved from the Montana Ground-Water Information Center
(GWIC) database in September 2006. Consequently, the total number of wells in the Flathead Lake Ground-Water
Characterization Area is shown as 21,219 wells (Table 1, far right), compared to the earlier total of 18,327 wells
shown on Sheet 1, Map E. Map A illustrates the number of wells <100 ft deep per Public Land Survey System (PLSS)
section within the study area. Maps B through D illustrate individual wells of specific depth intervals located within 1
mile of major streams. Maps E and F show the distribution and depths of irrigation, commercial, industrial, and public
supply wells located within 1 mile of major streams.
Industrial
Livestock
1,900
Unused
86%
Other
Table 1
Number of wells by selected use, proximity to streams, and depth
Thirty percent of the 21,219 well records for the Flathead Lake Ground-Water Characterization Area are for relatively
shallow wells, <100 ft deep (Map A). Fifty-eight percent of all well records are within 1 mile of a major stream (Maps
B through D). Twenty percent of all well records are both shallow (<100 ft deep) and within 1 mile of a stream
(Map B). The numbers of higher yield wells for uses such as irrigation, commercial, industrial, and public water supplies that are within 1 mile of streams are modest compared to similar numbers for all water uses (Maps E and F).
Eighty-six percent of well records in the Flathead Lake Ground-Water Characterization Area are for domestic use wells
(see the statistics at far right). Estimates of consumptive use by the US Geological Survey provides another perspective.
The total estimated consumptive use of ground water for Flathead and Lake Counties is about 15,200 acre-ft per year.
The total amount of water withdrawn from both surface and ground-water sources annually in these counties is about
661,000 acre-ft. For comparison, the average annual discharge of Flathead River at Polson is about 8,360,000 acreft. Further work might combine water use estimates with specific well locations to determine areas where streamflow
may be significantly impacted by ground-water use, and whether such impacts conflict with other uses.
Montana Ground-Water Information Center, Montana Bureau of Mines and Geology, Montana Tech of The University
of Montana (http://mbmggwic.mtech.edu/).
Natural Resource Information System, Montana State Library, for base map coverages (http://nris.mt.gov/).
Cannon, M.R., and Johnson, D. R., 2004, Estimated water use in Montana in 2000: US Geological Survey
Scientific Investigations Report 2004-5223, 50 p.
1,000
Domestic
2%
SCALE: 1:1,000,000
References
Estimated consumptive use of ground water
General distribution of wells by use
3%
509 wells
Miles
5 10
Statistics for Wells in the Flathead Lake Ground-Water Characterization Area
.
.
All uses
Commercial
Domestic
Irrigation
Public water supply
Industrial
Stockwater
Unused
Other
All wells
Wells within 1 mile
of major streams
Wells within 1 mile
of major streams
and less than or equal
to 100 ft deep
21,219
114
18,376
382
536
75
225
365
1,146
12,492
83
10,717
247
370
56
100
202
717
4,314
43
3,526
119
94
18
47
145
322