Ground-Ground- WaterWater inin thethe ClarkClark ForkFork BasinBasin Well 109142: 06N 19W 07 BABC- Ravalli County TomTom Patton,Patton, JohnJohn LaFave,LaFave, andand LarryLarry SmithSmith MontanaMontana Ground-WaterGround-Water AssessmentAssessment SeptemberSeptember 27,27, 20062006

The Ground-Water Assessment Program at the Montana Bureau of Mines and Geology conducts aquifer characterizations for the state of Montana. To date the program has produced two atlases, 34 maps, and several open-file reports describing the hydrogeology of 14 Montana counties. The Assessment Program operates a long-term monitoring network of about 900 wells from which it collects water-level and water-quality data. Long-term water-level records are useful when impacts from climate, development or other factors must be evaluated. All data collected by the program is put into the Ground-Water Information Center (GWIC) database which in addition houses ground-water data for about 200,000 Montana wells. GWIC can be reached on the web at http://mbmggwic.mtech.edu.

1 Clark Fork Basin

Kalispell

Thompson Falls

Missoula N

Hamilton 50 Mi Butte

The Montana portion of the Clark Fork basin covers about 21,459 square miles and extends from the river’s head waters near Butte, Montana north along the Continental Divide to where the North Fork of the Flathead River enters the country from Canada. A portion of the basin extends northward from there into British Columbia Canada. The river leaves Montana below Noxon at its border with Idaho. Much of the basin consists of intermontane valleys that began developing during the Tertiary and that are connected by relatively narrow, incised canyons.

1 Geology

N

50 Mi

Alluvium Glacial Tertiary

The intermontane valleys are filled with sediment generally derived from surrounding bedrock. The sediment has been transported into the basins by smaller streams tributary to major through-flowing branches of the Clark Fork. These sediments may occur as alluvial fans along the valley margins but are often fine grained and may not be aquifers. Alluvium is deposited along most streams and often contains the most prolific aquifers. A thick well-sorted gravel was deposited in the Kalispell Valley by the Flathead Lobe of the Cordilleran ice sheet. Glacial Lake Missoula and its outwash floods modified the surficial geology in the southern part of the Flathead drainage and downstream of Missoula, Montana.

2 PreviousPrevious WorkWork

•• Kendy,Kendy, E.,E., andand Tresch,Tresch, R.,R., 1996, 1996, Geographic, Geographic, geologic,geologic, andand hydrologichydrologic summariessummaries ofof intermontaneintermontane basinsbasins ofof thethe NorthernNorthern RockyRocky Mountains,Mountains, Montana,Montana, U.U.S.S. GeologicalGeological SurveySurvey Water-Water- ResourcesResources InvestigationsInvestigations ReportReport 96-4025,96-4025, 233P.233P.

•• LaFave,LaFave, J.,J., Smith,Smith, LL.,., Patton,Patton, T.,T., 2004,2004, Ground-waterGround-water resourcesresources ofof thethe FlatheadFlathead LakeLake Area:Area: FlFlathead,athead, Lake,Lake, andand partsparts ofof MissoulaMissoula andand SandersSanders counties.counties. PartPart A-A- Descriptive Descriptive overview,overview, MontanaMontana BureauBureau ofof MinesMines andand Geology:Geology: Ground-waterGround-water AssessmentAssessment AtlasAtlas 2,2, 132132 p,p, andand partpart B,B, 1111 plates.plates.

•• Smith,Smith, L.,L., LaFave,LaFave, J.,J., andand Carstarphen,Carstarphen, C.,C., Ground-waterGround-water resourcesresources ofof thethe Lolo-BitterrootLolo-Bitterroot Area:Area: Mineral,Mineral, Missoula,Missoula, andand RavalliRavalli counties.counties. PartPart B,B, 1010 mapsmaps (open-file(open-file versions).versions).

2 HydrogeologicHydrogeologic setting:setting: BitterrootBitterroot ValleyValley RepresentsRepresents valleysvalleys filledfilled withwith debrisdebris fromfrom valleyvalley margins.margins. MayMay havehave channelchannel depositsdeposits fromfrom throughthrough flowingflowing streamsstreams moremore oror lessless centralcentral inin thethe basin.basin. (Missoula,(Missoula, DeerDeer Lodge,Lodge, Drummond,Drummond, others)others)

W E Hamilton

r

ve i R Shallow

t o B o sand & gravel r e r e d t t r i o B c k ck dro Be ~2,500 ft

3 HydrogeologicHydrogeologic setting:setting: KalispellKalispell ValleyValley Kalispell

WE

d River a e h t a l F

? The Kalispell valley is different Deep AquiferDeep alluvium

The Kalispell valley is different ~3,000 ft becausebecause aa thickthick alluvialalluvial T ertia sequencesequence waswas depositeddeposited duringduring ry? thethe Pleistocene.Pleistocene. TheThe deepdeep alluviumalluvium isis thethe primaryprimary aquiferaquifer throughoutthroughout thethe valley.valley.

4 HydrogeologicHydrogeologic settingsetting -- canyons canyons

InIn mostmost canyoncanyon settingssettings valleyvalley fillfill isis 30-30- 5050 ftft thick.thick. WellsWells areare developeddeveloped inin thethe near-streamnear-stream alluviumalluvium oror fracturedfractured bedrockbedrock alongalong thethe valleyvalley margins.margins. InIn thethe ClarkClark ForkFork valleyvalley belowbelow MissoulaMissoula outwashoutwash floodsfloods fromfrom GlacialGlacial LakeLake TarkioTarkio MissoulaMissoula deepeneddeepened thethe valleyvalley andand depositeddeposited substantialsubstantial thicknessesthicknesses ofof alluvium.alluvium.

NWNW SESE ClarkClark ForkFork GlacialGlacial lakelake depositsdeposits Sand and gravel

~400 ft Bedrock 1 Mi

5 IntermontaneIntermontane basinbasin aquifersaquifers T e r t ia r y Flood plain and r B e low terraces C v e i a n n R c tary a bu h Tri l C e

a s n Shallow basin a fill aquifers l Fractured rock DeepDeep aquifers basinbasin fillfill aquifersaquifers DeepDeep TertiaryTertiary depositsdeposits

Ground-water flow in the intermontane basin aquifers is generally from the edges and upper ends to the center and then down valley. Important recharge sources are provided by tributaries and by irrigation canals. Water also enters the basin fill from the surrounding mountains as recharge. Confining zones may cause aquifers to be separated into near-surface and deep zones that locally may exhibit separation. However, the valley acts on a whole as a single hydrogeologic unit.

6 ClarkClark ForkFork Basin:Basin: precipitationprecipitation andand dischargedischarge

3 Precipitation: 22.06 m Af: Discharge: 13.74 m Af Evaporation, ET, and consumptive use: 8.32 m Af 2 6

Af X 10 1

0

Precipitation/Discharge: Precipitation/Discharge: Jan Feb Mar Apr May Jun Jul Aug Sep Oct Nov Dec

1971-20041971-2004 averageaverage monthlymonthly precipitationprecipitation (Af)(Af) 1971-20041971-2004 averageaverage dischargedischarge nearnear PlainsPlains MTMT (Af)(Af)

•Precipitation volume based on 1971-2004 monthly precipitation for the Western Climate Division. Precipitation data from the Western Regional Climate Center at http://www.wrcc.dri.edu. •Discharge volume from monthly average flow data measured at USGS gage12389000, Clark Fork near Plains MT. •The difference between water into the basin as precipitation water leaving the basin as discharge is made up by evaporation, evapotranspiration, and consumptive use. •The volumes shown are to provide an “order of magnitude” for the amounts of water involved. Other measures may provide more refined numbers, particularly for precipitation.

7 ClarkClark ForkFork BasinBasin waterwater wellswells

Kalispell Kalispell

Thompson Thompson Falls Falls N

Missoula Missoula 50 mi Wells Total wells Hamilton Hamilton Butte since Butte in GWIC: 1995: 60,008 20,679

•Ground-water development is significant within the basin. Logs for more than 60,000 water wells are recorded in the Ground-Water Information Center (GWIC) at the Montana Bureau of Mines and Geology. •Is the development intercepting water that would become surface flow, and if so, are downstream (senior) water rights being impacted? Population in the basin is increasing and many of those moving into the area drill wells for domestic and other purposes.

8 Ground-waterGround-water developmentdevelopment

••ClarkClark ForkFork basinbasin aboveabove Kalispell MilltownMilltown closedclosed toto newnew ground-waterground-water develop-develop- Thompson Falls mentment without without aa SW/GWSW/GW reportreport andand anan augmen-augmen- Missoula tationtation plan. plan. N ••WellWell densitydensity mapsmaps 50 mi Hamilton provideprovide aa wayway toto Butte evaluateevaluate growth.growth. Wells: 60,008

The next several slides detail well-drilling densities by sub basin and the numbers of wells drilled since 1990. In the notes pages are ancillary graphs showing the numbers of state wide monitoring wells, well uses, depth histograms, and construction rates.

9 ClarkClark forkfork –– below below FlatheadFlathead RiverRiver 2,5292,529 wells:wells: 87%87% DomesticDomestic Cumulative wells 2020 MiMi 100

50

Noxon 0 Percent of wells of Percent 1975 1980 1985 1990 1995 2000 2005 2010 Year

11 well/40well/40 ac.ac. 11 well/5well/5 ac.ac. 1 well/20 ac. 1 well/2.5 ac. T21N29W23: 89 wells 1 well/20 ac. 1 well/2.5 ac. 11 well/10well/10 ac.ac. 11 well/<2.5well/<2.5 ac.ac.

500 401 sections with wells in 2,124 mi2 (19%) 323

Plains Sections 46 27 2 3 0 >80 79-40 39-20 19-10 9-5 4-2.5 <2.5 Acres for each well

Construction rates 1000 13% Well use Domestic 500

Wells Stock Irrigation 0 1975 1980 1985 1990 1995 2000 2005 2010 87%87% Public Supply Year Other

Well depths State wide Monitoring 0750Total Wells <= 50 Min. Med. Max 100-200 Meas. 32 39 42 300-400 Years 10 11.5 13 Depth (ft) 500-600 Total wells in basin: 6

One monitoring well / 422 wells

10 FlatheadFlathead RiverRiver aboveabove ParadiseParadise 20,89720,897 wells:wells: 86%86% domesticdomestic Cumulative wells 2020 MiMi 100

50

0 Percent of wells of Percent Kalispell 1975 1980 1985 1990 1995 2000 2005 2010 Year T28N21W08: 132 wells 11 well/40well/40 ac.ac. 11 well/5well/5 ac.ac. 11 well/20well/20 ac.ac. 11 well/2.5well/2.5 ac.ac. Polson 11 well/10well/10 ac.ac. 11 well/<2.5well/<2.5 ac.ac.

1,500 1,909 sections with 1271 wells in 8,464 mi2 (23%)

Sections 244 229 131 33 1 0 >80 79-40 39-20 19-10 9-5 4-2.5 <2.5 Acres for each well

6000 Construction rates Well use 14% Domestic 3000 Stock Irrigation

Wells 0 1975 1980 1985 1990 1995 2000 2005 2010 86%86% Public Supply Year Other

Well depths State wide Monitoring 0 9,000 Total Wells Min. <= 50 Med. Max

100-200 Meas. 26 79 7,664

300-400 Years 5 14 63 Depth (ft) 500-600 Total wells in basin: 91 One monitoring well / 230 wells

11 1963-1972 2965 M:702938 2955

5 ft interval M:131524 1973-2002 2945 JFMAMJJASOND

2920 M:131524 2910 Jan-63 Jan-71 Jan-79 Jan-87 Jan-95 Jan-03

M:702938 M:131524 TD = 152 Long-termLong-term TD = 278 hydrographshydrographs andand developmentdevelopment

12 BedrockBedrock 2,874 wells aquiferaquifer development:development: KalispellKalispell ValleyValley---- 19751975

14%

86%

13 BedrockBedrock 9,794 wells aquiferaquifer development:development: KalispellKalispell ValleyValley---- 20012001

26%

74%

14 Middle Clark Fork

Cumulative wells 100 6,6636,663 wells:wells: 82%82% domesticdomestic 50

0 St. Regis wells of Percent 1975 1980 1985 1990 1995 2000 2005 2010 Year

11 well/40well/40 ac.ac. 11 well/5well/5 ac.ac. T13N20W14: 11 well/20well/20 ac.ac. 11 well/2.5well/2.5 ac.ac. 267 wells 11 well/10well/10 ac.ac. 11 well/<2.5well/<2.5 ac.ac.

Missoula 400 415 sections with wells in 1,994 mi2 (21%) 260 2020 MiMi

Sections 46 50 42 12 41 0 >80 79-40 39-20 19-10 9-5 4-2.5 <2.5 Acres for each well

2000 Construction rates Well use 16% Domestic 1000 Stock Irrigation 0 Wells 1975 1980 1985 1990 1995 2000 2005 2010 82%82% Public Supply Other Year

Well depths State wide Monitoring 0Total Wells 3,000 Min. <= 50 Med. Max 100-200 Meas. 27 40 7,662 300-400 Years 6 11 21 Depth (ft) 500-600 Total wells in basin: 24 One monitoring well / 281 wells 15 MissoulaMissoula ValleyValley 20000 0 5 1 0 3 4 1 0 3 15000 3 USGS station 12340500 1 151190 3 er 10000 iv k R or F rk L 0 Discharge (cfs) 5000 la in 2 C e 1 o 3 f S 0 ec Jan-96 Jan-97 Jan -98 Jan-99 Jan-00 Jan-01 Jan-02 Jan-03 tio 3145 n

3140 151189 151190 r ve 3135 Ri ot 151189 rro 3130 tte Bi 3125 Ground-Water

feet abovefeet mean levelsea 3120 Jan- Jan- Jan- Jan- Jan- Jan- Jan- Jan- flow 96 97 98 99 00 01 02 03

3200 Bitterroot Clark s Fork and and gravel

basal gravel Te rtiary (non aquifer) 3000

16 BitterrootBitterroot Cumulative wells Florence 100

50

0 Percent of wells of Percent 1975 1980 1985 1990 1995 2000 2005 2010 Year Hamilton 11 well/40well/40 ac.ac. 11 well/5well/5 ac.ac. 11 well/20well/20 ac.ac. 11 well/2.5well/2.5 ac.ac. 11 well/10well/10 ac.ac. 11 well/<2.5well/<2.5 ac.ac.

Darby 500 815 sections with wells 406 in 2,860 mi2 (28%) T08N20W30: 342

T06N20W31: 352 96 130 110 Sections 54 17 2 2020 MiMi 0 >80 79-40 39-20 19-10 9-5 4-2.5 <2.5 Acres for each well 18,89418,894 wells:wells: 87%87% domesticdomestic

5000 Construction rates Well use 13% Domestic Stock Irrigation

Wells 0 1975 1980 1985 1990 1995 2000 2005 2010 87%87% Public Supply Year Other

Well depths State wide Monitoring 0Total Wells 8,000 <= 50 Min. Med. Max 100-200 Meas. 1 75 7,647 300-400

Depth (ft) Years 0 12 50 500-600 Total wells in basin: 43

One monitoring well / 439 wells 17 Irrigation influence

2020 MiMi

18 MonthlyMonthly averages:averages:

Hamilton

Florence Each division = 2 ft Each division Each division = 2 ft Each division JanJan MarMar MayMay JulJul SepSep NovNov

136486136486 10N10N 20W20W 1212 CDCDCDCD TotalTotal DepthDepth (ft):(ft): 5252 136964136964 06N06N 20W20W 1919 CCCCCCCC TotalTotal DepthDepth (ft):(ft): 4040

Surface and ground-water interaction Wells that are in aquifers heavily dependent on the distribution of surface water for irrigation have typical hydrographs similar to the Hamilton well. Water levels begin to rise quickly during a 1-2 month period after the irrigation season begins. Continual application of water throughout the irrigation season supports the water table at a high level. After irrigation water is turned off in the late summer or fall, water levels begin to fall. Wells that are in aquifers related to direct recharge by rivers or streams have hydrographs that more or less follow the discharge as recorded in the stream. Water levels will peak near the time that stream flow peaks and begin to fall back to a base level.

19 BitterrootBitterroot arsenicarsenic

non-detectnon-detect 5.05.0 –– 10.0 10.0 ug/Lug/L << 5.05.0 ug/Lug/L >> 10.010.0 ug/Lug/L

Yc Middle Belt Carbonate

Will ow Creek Tgw Tm Mylonite Zone Mylonite

Yc Taf

Willow Creek and related intrusive rocks (granodiorite w/ diabase dikes.

20 6,0016,001 wells:wells: 82%82% domesticdomestic UpperUpper Clinton ClarkClark ForkFork

Cumulative wells 100 Deer Lodge

50 T05N11W30: 167

0 Percent of wells of Percent 1975 1980 1985 1990 1995 2000 2005 2010 Year

755 sections with 600 Butte 613 wells in 2,320 mi2 (33%) Sections 64 43 19 14 2 1 well/40 ac. 1 well/5 ac. 0 1 well/40 ac. 1 well/5 ac. >80 79-40 39-20 19-10 9-5 4-2.5 <2.5 11 well/20well/20 ac.ac. 11 well/2.5well/2.5 ac.ac. Acres for each well 11 well/10well/10 ac.ac. 11 well/<2.5well/<2.5 ac.ac.

2500 Construction rates Well use 18% Domestic Stock Irrigation

Wells 0 1975 1980 1985 1990 1995 2000 2005 2010 82%82% Public Supply Year Other

Well depths State wide Monitoring 02,500 Total Wells Min. <= 50 Med. Max 100-200 Meas. 14 74 8,499 300-400 Years 1 14 46 Depth (ft) 500-600 Total wells in basin: 24

One monitoring well / 250 wells 21 ClarkClark ForkFork Basin:Basin: NitrateNitrate 2 – 10 Kalispell 2 – 10 0.3%0.3% >> 1010 mg/Lmg/L mg/Lmg/L 12% 710710 54% samplessamples 34% < 2 non W/OW/O mg/L detect. ButteButte

Missoula

11% 4747 30% samplessamples nearnear 48% 11% ButteButte

MBMG – Ground-Water Assessment Program

22 BlackfootBlackfoot BasinBasin

2,7692,769 wells:wells: 88%88% domesticdomestic Cumulative wells 100

50

0 Seeley Lake wells of Percent 1975 1980 1985 1990 1995 2000 2005 2010 T14N09W24: 149 Year

462 sections with Potomac Lincoln 500 391 wells in 2,316 mi2 (20%)

Sections 38 19 9 4 1 0 >80 79-40 39-20 19-10 9-5 4-2.5 <2.5 11 well/40well/40 ac.ac. 11 well/5well/5 ac.ac. Acres for each well 11 well/20well/20 ac.ac. 11 well/2.5well/2.5 ac.ac. 11 well/10well/10 ac.ac. 11 well/<2.5well/<2.5 ac.ac.

Construction rates Well use 750 12% Domestic Stock Irrigation 88% Wells 0 1975 1980 1985 1990 1995 2000 2005 2010 88% Public Supply Other Year

Well depths State wide Monitoring 0Total Wells 1,000 Min. <= 50 Med. Max

100-200 Meas. 34 57 5,176

300-400 Years 6 11.5 31 Depth (ft) 500-600 Total wells in basin: 10 One monitoring well / 279 wells

23 RockRock andand FlintFlint CreekCreek BasinsBasins

1,4281,428 wells:wells: 89%89% domesticdomestic Cumulative wells 100

50 Drummond 0 Percent of wells of Percent 1975 1980 1985 1990 1995 2000 2005 2010 Year

300 264 sections with wells 228 in 1,281 mi2 (19%) T05N14W24: 106 Sections Georgetown 22 6 7 1 0 Lake >80 79-40 39-20 19-10 9-5 4-2.5 <2.5 Acres for each well

11 well/40well/40 ac.ac. 11 well/5well/5 ac.ac. 11 well/20well/20 ac.ac. 11 well/2.5well/2.5 ac.ac. 11 well/10well/10 ac.ac. 11 well/<2.5well/<2.5 ac.ac.

Construction rates Well use 500 11% Domestic Stock Irrigation

Wells 0 1975 1980 1985 1990 1995 2000 2005 2010 89%89% Public Supply Other Year

Well depths State wide Monitoring 0500Total Wells Min. Med. Max <= 50 Meas. 49 80 8,248 100-200 Years 6 11.5 13 300-400

Depth (ft) Total wells in basin: 9 500-600 One monitoring well / 159 wells 24 ClarkClark Fork:Fork: wellwell densitiesdensities

15001500

10001000 <=<= 88 17-3217-32 500 500 Sections WW Sections ee 65-12865-128 ll llss 257-352257-352 RR LL BB U MM BB FF 00 oo oo l p iid ii ll w laa p d ttt aa cc w cc dldl tee tt kk ee kk e e rrorro hh //F rr f r e ee F foo C CC aa lli CC o . oo d inn .. o .F .FF t d t FF tt .. t t ..

25 Clark Fork: drilling rates

4,0004,000

3,0003,000

s s l l l 2,0002,000 l

e e

W W 1,0001,000 19801980 19851985 19901990 YY 0 FF 0 ee 19951995 BB l MM laa aa U ii t 2000 ii ttt thh rr 2000 BB p dd tee e LL l p dldl rrorro e o laa e aa 20052005 RR o cc e e dd oo ww k r CC oo e k C . cc e ffo .FF tt kk rr o . . // CC oo F . FF tt . lli ..FF inn . tt .

26 ClarkClark Fork:Fork: developmentdevelopment 2%2% 0%,0%, 0%0% 6%6% 11 wellwell perper 2323 percentpercent (5,021(5,021 10%10% 8080 ac.ac. sectionssections inin 21,34921,349 4040 ac.ac. 22 11%11% 2020 ac.ac. mimi )) ofof thethe basin’sbasin’s 71%71% 1010 acac sectionssections containcontain 55 ac.ac. 2.52.5 acac wells.wells. <2.5<2.5 ac.ac.

20 Construction rates DuringDuring thethe lastlast 1515 10 yearsyears aboutabout 1,8001,800

0 wellswells havehave beenbeen

Wells x 1,000 1975 1985 1995 2005 constructed each year. Year constructed each year.

27 Summary:Summary: aa waterwater balance?balance?

Million A/f Sources Precipitation 22.06 1971-2004 average based on Western Climate Division data. Discharge 13.74 1971-2004 average annual discharge near Plains. Irrigation 0.28 MT DNRC water rights listings for irrigation use – September 2006. Municipal 0.21 MT DNRC water rights listings for municipal use – September 2006. Domestic 0.08 ~ 52,000 wells @ 1.5 af consumptive use each. Evap./ET 7.75 By difference.

28 Missoula Cumulative number of wells 12352500 above Missoula 18000 15000 87% are domestic 12000 wells 9000 Wells 6000 3000 0 1975 1985 1995 2005

Darby 12344000

29 Missoula Cumulative number of wells 12352500 above Missoula 18000 15000 87% are domestic 12000 wells 9000 Wells 6000 3000 0 1975 1985 1995 2005

Bitterroot River: mean monthly 18000 flow at Missoula Darby 15000 12344000 12000 9000 cfs 6000 3000 0 1975 1985 1995 2005

30 Missoula Cumulative number of wells 12352500 above Missoula 18000 15000 87% are domestic 12000 wells 9000 Wells 6000 3000 0 1975 1985 1995 2005

Bitterroot River: mean monthly flow and annual precipitation at Missoula

Darby 18000 30 12344000 15000 12000 20

cfs 9000 6000 10 In/yr 3000 0 0 1975 1985 1995 2005

31 Missoula Cumulative number of wells 12352500 above Missoula 18000 well 15000 87% are domestic 136486 12000 wells 9000 Wells 6000 3000 0 1975 1985 1995 2005

Mean monthly flow at Missoula and Ground-water level at Florence Darby 15000 2 12344000 Well 136486 10000 4

cfs 6000 6

0 8 Ft below ground 1990 1995 2000 2005

32 GWICGWIC SlideSlide

Most of the ground-water information presented today can be obtained from the Ground-Water Information Center at the Montana Bureau of Mines and Geology. Well logs, water-quality data, water-level data and Ground-Water Characterization Program maps products can be obtained from the website at http\:mbmggwic.mtech.edu.

33 MontanaMontana Ground-Ground- WaterWater AssessmentAssessment

SeptemberSeptember 27,27, 20062006

Well 101131: 01S 16E 28 BADC- Stillwater County (unused)

34