WATERRESOURCES
RESEARCH,
VOL.27,NO. 1,PAGES77-90,JANUARY1991
Light StableIsotopeSystematics
of Large-Scale
Hydrologic
Regimes in California and Nevada
NEIL L. INGRAHAM1 AND BRucE E. TAYLOR2
Departmentof Geology,University
of California,Davis
Surfacewaters,shallowgroundwaters,
andprecipitation
samples
werecollected
alongthree
traverses,
whichbeginattheCalifornia
coast
andareoriented
inaneast-west
manner,
roughly
parallel
to theatmospheric
flowpathof meteoric
water.Thehydrogen
isotope
compositions
fromshort-term
precipitation
records
variedasmuchas40%o
atonelocation
andwerenotrepresentative
oftheaverage
annualisotopiccomposition
of precipitation.
The hydrogen
isotoperatiosof surfacewatersand
shallowgroundwaters
distinguish
segments
with isotopicvariationsthat correlatewith measured
verticalfluxesof meteoric
water.Onecoastal
segment
appears
to closely
approximate
anopensystem
in whichprecipitation
dominates
overevapotranspiration.
Mostsegments
are described
by rather
regularvariationsin •SD:3-45%0per 100km, whichrepresent
differentdegrees
of closureof the
hydrologic
systemcausedby variablepartitioning
of precipitation
betweenrunoffandevapotranspiration.All partiallyclosedsystems
implyterrestrial
recycling
of water.A simplemodelestimates
this
amountto be about20%acrossnorthernandcentralCalifornia.Threesegments,
representing
the
Great Basin,showvirtuallyno geographic
variationand appearto representisotopicallyclosed
systems.
INTRODUCTION
not include prior precipitation over the ocean or upwind
evapotranspirationalreturn and recycling of water.
West-to-east variations in the oxygen and hydrogen isotope composition of surface waters and shallow ground
watersacrossnorthernCalifornia and Nevada reflectgeneral
isotopicchangesin atmosphericwater vapor accompanying
continuedprecipitation and recycling of water by evapotranspirationupwind [Ingraham and Taylor, 1986]. These
variations,modeledin terms of isotopicfractionationin open
and closed hydrologic systems, indicated a discrepancy in
the measured and Rayleigh model-predicted hydrogen isotope compositions of inland meteoric water which was
attributed to recycling. The results of the present study
incorporatemeasurementsacross central and southernCalifornia, and reveal additional complexities.
Reconnaissancehydrogen isotope studiesby Friedman et
al. [1964] indicate the profound effects of geography(primarily distance inland and elevation) on the compositionsof
In a study of water balance in the Amazon Basin, Salati et
al. [1979] determined the oxygen isotope composition of
precipitationin the basinand found a very small (0.075%0per
100 km) isotopic depletion with distance inland from the
Atlantic Ocean. They attributed the small depletion to a
large contribution from reevaporated moisture. Similarly,
Rozanskiet al. [1982a] modeled the stableisotope composition of atmosphericwater vapor and precipitation in central
Europe with respect to distancefrom the Atlantic Ocean and
included the effects of winter precipitation and summer
evapotranspiration. They documented decreases in •SD of
3.3%oper 100 km in winter precipitation and 1.3%oper 100 km
in summerprecipitation. Rozanski et al. [1982b] concluded
that variations in local precipitation were primarily controlled by regional-scale precipitation/evapotranspiration
events upwind, modified only slightly by local temperature
surface waters in the United States. Friedman and Smith
fluctuations.Based on this, Rozanski [1985] interpreted the
[1970, 1972] studied the hydrogen isotope compositionof isotopic compositionof old European groundwatersas indiprecipitationand reported an orographiceffect acrossthe cating atmospheric circulation patterns similar to those of
SierraNevadaof 40%0per 1000m in elevation.Later, Smith the present. Yonge et al. [1989] studied the stable isotopic
ratios of surface waters across western Canada to the Great
et al. [1979] found highly variable deuteriumcontentsin
precipitationin central California, with differencesin
rangingfrom up to 114%o
between sequentialsamplesfrom
Divide and beyond. These researchers modeled the results
from over 500 km distance inland in terms of a single-stage
the same storm collected at one station to up to 37%ofor the Rayleigh distillation curve and concludedthat precipitation
mean values of/SD of individual storms at 13 stations. They west of the divide did not appear to be greatly affected by
modeledthe change in isotopic compositionof average evapotranspiration.
The present study bears on the history of meteoric water
precipitation
in southeastern
CaliforniaandwesternNevada
froma pseudoadiabatically
coolingair mass.Theirmodeldid in hydrologic regimes dominated by an eastward atmo-
spheric flux across California and Nevada. Variations in
1Nowat Water Resources
Center,DesertResearchInstitute, stable isotope ratios of surface waters and shallow groundwaters on a regional scale can be modeled effectively in
terms of precipitation, evapotranspiration,and runoff. This
approachincludesa somewhatlarger view of the hydrologic
cycle than most previousmodels, which have emphasized
the precipitation-dominatedorographiceffects.
Universityof Nevada, Las Vegas.
2Nowat Geological
Survey
of Canada,
Ottawa,
Ontario.
Copyright1991by the AmericanGeophysical
Union.
Papernumber90WR01708.
0043-1397/91/90WR-01708505.00
77
78
INGRAHAM
ANDTAYLOR:
STABLE
ISOTOPE
SYSTEMATICS
OFHYDROLOGIC
REGIMES
Traverse
Thirty-nine such rain samplerswere placed in selected
locationsalong the two traverses(I and II). Four setsof
I
samples
werecollected
alongtraverseII andonealong
traverse I. The rainwater caught in the collectorswas
measuredvolumetrically, and an aliquot was stored for
analysis.Several duplicate samplerswere left undisturbed
Traverse
Great
Pacific
the entire season (November to April) to collect the complete record of rain, which compared well both volumetri.
cally and isotopicallyto the summationof the short-term
data.
Basin
Ocean
Traverse
Ill
Six early springsnowcoreswere collectedalongportions
of traverse II in the Sierra Nevada of California, where
precipitationoccursprimarily as snow. The snow was cored
usinga modifiedMt. Rosesnowsamplerandsealedin plastic
containersand allowed to melt slowly. The meltwater was
then bottled, in the same manner as with other water
samples.
Fig. 1. Location of the three east-westtraversesused in this
study.The traverseswerepositioned
parallelto the atmospheric
flow pathand locatedto includemostmajorphysiographic
and
hydrologic provinces in California and Nevada. Also shown is the
regionof dominantlywinterprecipitation
[afterMarkham,1970].
Isotopic Analysis
Both the hydrogen and oxygen isotope ratios were determined using two different methods. Quantitative conversion
of water to hydrogengas was performed usingboth uranium
[Bigeleisenet al., 1952]andzinc [Kendalland Coplen,1985].
In the uraniummethod, hydrogenwas Toepier-pumpedinto
METHODS
a Pyrex glasstube (3/8 in OD x 12 in), sealedwith a torch,
and storedfor severalweeksfor analysis.With zinc, hydroSample Collection
gen gaswas producedand sealedin the same Pyrex tube (1/4
All sampleswere collectedin 125 ml (4 oz.) polysealed in OD x 6 in) usedfor reaction.The oxygenisotopeanalysis
glassbottles along three east-westtraversesacrossCalifor- of water was accomplishedprincipally by the CO2 equilibrania and Nevada (Figure l). The traverseswere alignedin a tion method [Epstein and Mayeda, 1953] but also by the
manner to determine the maximum changesin isotopic guanidine hydrochloride method [Dugan et al., 1985]. An
compositionin meteoricwater as it migratesfrom west to equilibriumoxygenisotopeCO2-H2¸ fractionationfactorof
east. The traverses were approximately equispacedand 1.0412(at 25øC)was used for the CO2 equilibrationtechincludedmost major physiographic
and hydrologicprov- nique [Freidman and O'Neil, 1977].All data are reportedin
inces in California and Nevada, includingthe Great Basin. the standard$ notationwith respectto SMOW. The repro-
Shallowgroundwaterswere consideredto be the type of
samplethat best representedaverageprecipitation,beingthe
least sensitiveto the extreme yearly, seasonal,and in-storm
isotopicvariability (suchasfound by Smithet al. [1979])and
yet reflectingthe current climate and hydrologicregime.
ducibilityof (SDis about1%oand of (5•80is about0.2%0.
RESULTS
Groundwaters
The stable isotope compositionsof all surface waters and
shallow groundwaters collected for this study are listed in
Eighty-five samples of shallow groundwater (including Table 1 and plotted by traversein Figure 2. For the mostpart
some surface waters) were collected for this study. An the data plot close to, but consistentlybelow, the presentadditional 35 isotopic analysesof groundwaterreported in day meteoricwaterline (MWL) (•D = 8•80 + 10; Craig
the literature were incorporated in the data base.
[1961]). However, some sampleswere collectedfrom therGroundwaters
Precipitation
mal springsand do not plot on the MWL, havingundergone
varying degreesof oxygen isotope exchangewith the host
rock at depths. The •D values of the spring samplesstill
carry the signature of meteoric water, since boiling is not
observed, and evaporative steam loss does not affect the
isotopic data [cf. Truesdell et al., 1977].
Precipitation(as rain and snow) was collectedto compare
with the surfacewater and shallowgroundwatersamplesand
to determine the stable isotope compositionof waters available for infiltration. Rain was collected along the coastal
Some of the data taken from the literature are for waters
portion of traverse I and also along traverse II in California
from 0 to 250 km inland. Rain sampleswere collected by a fromthe GreatBasinwith apparent•4Cagesranging
from
simple device consisting of a 2 L plastic bottle set inside a 11,000 to 28,200 years, and hence, the infiltration of these
nursery can backfilled with soil for stability. Tygon tubing waters may have occurred under slightly different climatic
with a restriction was attached to a funnel and placed conditions.Hydrogen isotope compositionsof paleowater
through a stopper in the neck of the bottle. A short length (15 samplesdepletedby morethan about5%orelativeto presentcm) of tygon tubing (0.8 mm ID) was inserted through a hole day meteoric water are thought to reflect a colder and more
in the stopper to release air displaced by water as the bottle humid climate [Merlivat and Jouzel, 1979]. Nevertheless,
filled. The small-diameter tubing restricted evaporation of theseolder waters do not deviate significantlyfrom modern
the sample.
sampleswith respect to the regional variations discussed.
INGRAHAMAND TAYLOR:STABLEISOTOPE
SYSTEMATICS
OF HYDROLOGIC
REGIMES
79
TABLE 1. Stable Isotope Compositionsof All SurfaceWaters and Shallow Groundwaters
Distance
From
Coast,
Collection
Occurrence
km
Date
Traverse
0.2
3
15
30
36
38
73
97
102
127
134
137
151
156
185, R
207
256
256H
269H
282
315
320
322, R
328H
328H
350
385
400H
400H
405H, M
412H, M
435H, M
440H, M
450H, M
450H, M
460H, M
465H, M
480H, M
530H, M
565H
665
700
800H, M
0.4
0.7
9
15.5
30
31
63
90
107
107
110
150
200
200
221
225
232
249
254
261
261
282
Location
8DsMow
-52
-50
-56
-63
-71
-69
-78
I
RoadcutSpring
stream
RoadcutSpring
RoadcutSpring
RoadcutSpring
RoadcutSpring
Waters Creek, Oregon
July 1983
July 1983
July 1983
July 1983
July 1983
July 1983
July 1983
T10N/R1E/31
T12N/R1E/23
T17N/R2E/26
T17N/R3E/9
T6N/R4E/15
T18N/R4E/4
T37S/R7W/9
irrigationwell
CanyonCreek, Oregon
irrigationwell, Oregon
Drew Creek, Oregon
StewartSpring
BigSpring
TubbsSpring,Oregon
Hunt Hot Spring
July 1983
July 1983
July1983
July 1983
July 1983
July1983
July1983
Aug. 1973
T42N/R49W/17
T30S/R5W/35
T34S/R1W/4
T31S/R1W/32
T41N/R6W/2
T40N/R4W/9
T39S/RSE/32
T37N/RlW/25
-94
-79
-96
-87
- 101
- 108
-104
-94
irrigation
well,Oregon
irrigation
well,Oregon
BieberHot Spring
CanbyHot Spring
RushSpring
StowSpring
MineralSpring
Leonards
Hot Spring
MenloHot Spring
LakeviewHot Spring,Oregon
Windmill,Vya
July1983
July1983
July1983
July1983
Aug.1985
July1983
Aug.1983
July1973
Aug.1983
Aug.1983
Aug.1983
T39S/R8E/23
T36S/R12E/22
T38N/R7E/12
T42N/R10E/28
T40N/R10E/24
T43N/R15E/27
T47N/R15E/1
T43N/R16E/13
T39N/RI7E/20
T39S/R20E/9
T42N/R19E/4
-96
-123
- 119
- 117
- 103
- 102
- 111
- 117
- 117
-125
- 119
HighRockCnynSpring
Hot Spring,
Soldier
Meadows
Hot Spring,
Soldier
Meadows
Gerlach
Hot Spring
HotSpring,
Soldier
Meadows
BogHotSpring
HarneyLakeHotSpring
flowing
well
Baltazor
HotSpring
Aug.1983
Aug.1983
Aug.1983
.-.
-..
...
...
...--
T40N/R23E/16
T40N/R24E/22
T40N/R24E/22
T42N/R23E/2
T40N/R24E/23
T46N/R28E/18
T27S/R29E/36
T46N/R28E/13
T46N/R28E/13
- 115
-129
-129
- 121
-130
-124
-129
- 126
-125
TroutCreekHotSpring
Howard
HotSpring
McDermit
HotSpring
Golconda
HotSpring
Beowawe
HotSpring
CarlinHotSpring
WhitePineHotSpring
.-.
...
--July1983
July1983
July1983
.--
T39S/R37E/16
T44N/R31E/4
T41N/R41E/20
T36N/R40E/29
T31N/R48E/8
T33N/R52E/33
T23N/R63E/6
-127
- 127
- 135
- 131
-130
-133
-128
Roadcut
Spring
Roadcut
Spring
Horse
Trough
Spring
Comptche
Spring
May1984
May1984
May1984
May1984
T!8N/R17W/18
TI8N/RI7W/18
T16N/R16W/9
T16N/RI6W/12
-37
-40
-42
-44
Montgomery
Woods
Spring
BlueLakeSpring
Bartlett
Spring
Barrel
Spring
Barrel
Spring
May1984
May1984
May1984
May1984
May1984
TI6N/R14E/15
TI5N/R10W/6
T15N/R8W/2
T15N/R5W/25
TISN/R5W/25
-45
-58
-68
-66
-65
DykeHotSpring
•
creek
domestic
well
domestic
well
domestic
well
domestic
well
domestic
well
Bithey
Spring
spring
White
Cloud
Spring
Skillman
Spring
Roadcut
Spring
spring
spring
81SOsMoW
.--
Traverse H
May1984
May1984
May1984
May1984
May1984
May1984
May1984
May1984
May1984
May1984
May1984
May1984
May1984
T43N/R30E/25
T18N/R15W/15
T15N/R5W/4
T16N/R2W/33
TI6N/R5E/16
T16N/R5E/16
T16N/R7E/13
T16N/R8E/20
T17N/R8E/25
T17N/R10E/22
T17N/R11E/30
T17N/R11E/22
T20N/R11E/25
T20N/R14E/31
- 128
-48
-58
-64
-59
-59
-69
-68
-71
-77
-74
-78
-89
- 105
-7.4
-7.6
-7.7
-8.6
-9.8
-9.1
-10.2
-11.5
-10.1
-12.4
-11.4
-12.2
-14.4
-13.4
-13.3
-10.8
-15.3
-14.5
-13.6
-14.0
-14.6
-15.2
-13.8
-14.8
-13.6
-14.6
-14.7
-16.5
-16.5
-14.7
-16.6
-15.3
-15.6
-15.3
-16.3
-16.2
-16.2
-16.5
-14.8
-16.2
-5.4
-5.6
-6.2
-5.9
-6.7
-6.6
-7.9
-8.4
-8.5
-8.6
-8.4
-8.4
-8.4
-8.5
-9.9
-9.8
-9.6
-10.5
-10.4
-10.7
-11.8
-13.7
80
INGRAHAM
ANDTAYLOR:
STABLE
iSOTOPE
SYSTEMATICS
OFHYDROLOGIC
REGIMES
TABLE
1.
(continued)
Distance
From
Coast,
km
285
294
298
323
325H
336H,M
390H,M
Collection
Occurrence
Roadcut
Spring
Donner
Summit
Spring
Hermes
PassSpring
FaradWarmSpring
Tressel
HotSpring
Location
Traverse H (continued)
May1984
May1984
May1984
July1984
July1984
585H,M
640H,M
750H,M
755H,M
KyleSpring
DixieHotSpring
Flowing
Well,DixieValley
SmithCreekHotSpring
Spencer
HotSpring
Bartholomae
HotSpring
MonteNevaHot Spring
CherryCreekHotSpring
'"
'"
'"
Oct.1985
'"
May1979
"'
'"
'"
"'
"'
20
22
26
50
54
60
74
84H
87
97
122
irrigation
well
irrigation
well
irrigation
well
irrigation
well
irrigation
well
artesian
well
irrigation
well
MercyHot Spring
irrigation
well
irrigation
well
irrigation
well
172
261
268
292
308
311
320
327
350
400
420
420
irrigationwell
spring
RedwoodCreek
KingsRiver
MatlockLake
OnionCreek
irrigationwell
spring
irrigation
well
ScottysCastleSpring
StovepipeWells
Stovepipe
Wells
445W
445W
445W
457H
TravertineSpring
Texas Spring
NevaresSpring
BeattyHot Spring
457
472W
490W
domestic
well
well
well
515W
515W
520W
575W
580W
well
well
well
Hiko Spring
CrystalSpring
410H,M
470
480H,M
485,J
530H,M
Steamboat
HotSpring
FernlyHotSpring
Date
LeeHotSpring
T19N/RI4E/24
T17N/R15E/8
T19N/R15E/14
T19N/RI8E/30
T21N/RI7E/I
1
T18N/R20E/33
T20N/R26E/18
unsurveyed
•DsMow
-94
-91
- 103
- 111
- 115
- 117
-122
-126
• 1SOsMow
- 12.5
- 13.5
- 13.5
- 13.8
- 15.1
- 12.2
-13.3
-13.2
....
T22N/R35E/8
T21N/R35E/10
TI7N/R39E/11
unsurveyed
T18N/R50E/28
T21N/R63E/24
T23N/R63E/6
123
- 126
- 130
-130
- 136
-128
-128
-128
- 15.9
- 16.3
-16.7
- !6.0
-16.3
-16.7
-16.2
June1984
June1984
June1984
June1984
June1984
June1984
June1984
June1984
June1984
June1984
June1984
TI 4S/R3E/25
TI4S/R4E/19
T15S/R4E/9
T14S/R6E/14
T14S/R6E/25
T18S/R7E/17
T15S/R9E/17
T14S/RIOE/15
T!5S/RIOE/23
T13S/RI1E/26
T!4S/R14E/1
June1984
June1984
June1984
June1984
June1984
July1984
July1984
July1984
July1984
July1984
TI4S/R17E/2
T14S/R27E/I
1
TI4S/R28E/9
T13S/R30E/17
T13S/R33E
T13S/R34E
T10S/R34E/16
TgS/R35E/17
TSS/R37E
T1!S/R42E/I
-43
-40
-46
-43
-47
-53
-61
-57
-64
-71
-73
-79
-96
-88
-- 107
- 101
- 109
- 101
- 123
- 126
- 112
- 5.7
-4.9
-6.2
-5.6
-6.3
-6.6
-8.0
-5.4
-7.8
-9.8
-9.8
- 10.1
- 12.8
- 11.4
- 14.0
- 13.4
- 14.7
- 13.4
- !5.9
- 16.1
- !4.1
July 1984
July1984
'"
'"
"'
July 1984
July1984
.......
.......
.......
.......
T15S/R45E/16
TI5S/R45E/16
-
- 13.3
- 13.1
Traverse
14CAge
III
.......
......
.......
T29N/RIE/23
T29N/R1E/15
T28N/R2E
T12S/R47E/8
T12S/R47E/8
107
!05
109
108
109
112
112
108
104
114
107
114
- 113
109
-
14.3
14.2
14.2
13.0
- 13.0
- 14.3
23,100
24,000
17,000
11,000
28,200
22,900
14,800
22,000
20,500
W, Waddell
et al. [1984];
M, Marineretal. [1975];
J,Jacobson
etal. [1983];
R, Reed[1975].
H, samples
collected
fromhotsprings
(T
> 40øC).Whereavailable,14Cagesarelisted.
The •D values of samplesfrom each traverseare plotted,
in Figure 3, versus latitudinal distance from the Pacific
Ocean. The traverses are divided into segmentsto indicate
hydrologic regimes of differing isotopic characteristics.The
northernmost traverse (traverse I) contains three distinct
segments, or regimes, while the other two traverses each
contain four. The isotopic variations of surface waters and
shallow groundwatersbetween segmentsmay be compared
to variations
in precipitation
[Goodridge
et al., 1981],potential evapotranspiration,
asmeasured
fromClassA evaporation pans [MacGillivray et ai., 1975], and elevation. There
may be fine structureto the isotopic"trends," and the
regressionlines greatly simplify the observedvariations.
However,the trendsdescribedare usefulfor comparison
andforma basisfor discussion
of large-scale
processes.
Segment I-a displays a marked, curvilinear decreasein
INGRAHAM AND TAYLOR: STABLE ISOTOPESYSTEMATICSOF HYDROLOGIC REGIMES
-2O
81
the position of the storm as it passes across the coast,
headingeastwardacrossthe state. A general pattern of
decreasing/SDwith distanceinland •.comparable
to that in
-4O
shallowgroundwaters)
is apparent,but the 6D of precipitation collectedat one locationmay vary up to 40%0between
sample sets.
However,the oxygen-hydrogen
isotopeequilibriumrelationshipis frequentlyinterruptedby excursionsof the data
from the MWL, typicallyabove the line. These deviations
may representthe effectsof nonequilibrium,kinetically
I
controlledisotopicfractionationof the storm's water mass,
or portionsthereof,by recondensation
and mixingof evaporatedwaterin isotopicallyinhomogenous
stormcells.The
stableisotopicdataof short-termrain samplesare generally
lesseffectivein defininghydrologicregimesthanare dataon
-1 oo
surface waters and shallow groundwater.
ll
-140
-18
-16
-14
-12
-10
-8
-6
-4
6180SMOW
The weightedaveragehydrogenisotopecomposition
of
precipitation
andthe hydrogenisotopecompositions
of the
snowsamplesfrom traverseII are plottedwith the hydrogen
isotopecompositions
of surfacewatersand shallowgroundwatersin Figure6. The large-scale
variationsin the weighted
average/SDvaluesof precipitationcorrespondcloselywith
Fig.2. Plotof •D versus
•180of surface
watersandshallow the/SD values of the surface waters and shallow groundwagroundwaters
on traverse I (solid squares),traverseII (open ters,whichsuggest
that surfacewatersand shallowgroundsquares),
andtraverseiiI (solidtriangles),collectedfor thisstudy. waterstend to averageout yearly, seasonal,and in-stormas
Themeteoricwaterline 6D = 8•180 + 10is alsoshown.
well as smallgeographic
variationsof the isotopiccomposition of precipitation.However, both the rain and snow
8D, from -50 to almost -85, for an averagedepletionof appearto be slightlydepletedin deuteriumrelative to
surfacewaters and groundwatersat the same locations,
60%0per 100 km. Segmentsrepresentingthe Great Basin
perhaps
(I-c, II-d, and Ill-d), a vast area of interiordrainage,show infiltration.due to slightevaporationof meltwaterprior to
little further decrease in 8D with distance from the coast. All
othersegmentsappearto be more regular,lineardepletion
DISCUSSION
trends of various slopes.
The isotopic variation within each segmentappearscontinuouson a large scale,and each segmentadjoinsanother,
Atmospheric
condensation
is thoughtto occurunderequilibrium conditions [e.g., Dansgaard, 1964], controlled
largelyby Rayleighdistillation.The hydrogenisotopecom-
exceptfor segment"d" of traverseIII. The average/SD
of
watersamplesfrom segmentIII-d (approximately
-110%o)
marksan abruptincreaseof about20%0
fromtheterminus
of positionof the precipitationcan be expressedby 6D =
(Fv
a-• - 1) x 1000whereF•, is thefractionof watervapor
segmentIII-c (- 125 to - 130%o).
remaining
in the cloud,and a is the temperature-dependent
fractionation factor for deuterium between the liquid and
Precipitation
vapor.
All precipitation
samples
wereanalyzed
for theirhydrogen The results of isotopic analysis of groundwatersand
alongtraversesacrossCaliisotopiccompositions,
and mostwere analyzedfor their weightedaverageprecipitation
oxygenisotopiccompositions.
Table 2 lists the type of fornia and into Nevada reflect a common set of meteorologThe mostimportantprocesses
causingthe
precipitation
collected(rain or snow),date of collection, ical processes.
are precipitation
and evapotranspiradistancefrom the coast,amountcollected(in centimeters), isotopicfractionation
and isotopic compositions.
TraverseI. The amount of rain recorded at the Crescent
tion. Initial resultsof a studyof eastwardmovingmoisturein
northern California and Nevada [Ingraham and Taylor,
Cityweatherstationduringtheperiodof collection
(January 1986] indicatedthat precipitationdominatedinitially but
Isotopic
20to March30, 1985)variedfrom73%(February)to 85% soongaveway to increasingevapotranspiration.
(March)of normal.The hydrogenisotopedatafor rain variations in central and southern California can be similarly
samples
areshownwithrespect
to distance
fromthePacific modeled,but additionalcomplicationsmustbe considered.
As discussed here, the boundaries of the system are
Oceanmeasured
alonga line of latitude,in Figure4. The
dataexhibitasmuchasa 40%o
per50kmdecrease
in/SDwith broadenedbeyondthose of the cloud (as the systemis
model)to
distancefrom the coast. The decreaseis continuousand usuallydescribedin a precipitation-dominated
appears
to exhibita largecurvilinear
trendas foundfor includethe groundsurfaceto a shallowdepth beneath.
surface
watersandshallow
groundwaters
alongsegment
I-a. Therefore shallow groundwatersare thought generally to
Traverse
H. All pairsof thehydrogen
andoxygen
iso- reflectthe isotopiccompositionof the system,as defined.
In this expandedsystemthe eastwardmovingmoisture
topedataof raincollected
alongtraverse
II areplottedin
becomes
depletedin deuteriumby continuedprecipitation.
Figures
5a-5dfor eachindividual
sampling
runversus
dis-
wereremoved
fromthesystem
viarunoff,
tanceinland.Therainsamples
wereproduced
fromthesame If allprecipitation
leaving
none
to
be
recycled
back
to
the
atmosphere
by
stormsystem
andareconnected
in a fashion
whichtracks
82
INGRAHAM
ANDTAYLOR:
STABLE
ISOTOPE
SYSTEMATICS
OFHYDROLOGIC
REGIMES
Prec:pilalion
.....
3001
;ooJ"'"
..... ...
'
- -
I
..............................:......
,_
-..."="• ...... '"'-7.-'----_...-_._"-"'---•..'_...'•-: •
- - .............
•000m
f 1000m
'SO
• '60
cO -IO0
• -120-
'140
i.
0
OislonceFromCoasl,km
[levelion
,
,,
Precipdolion
•OO
•
[vopolronspirotion
........
• zoot
........
-.
'10 -•.•c'%•--•
.........
•.,.,:. ',_..., ......................................
3000m
2OChre
IOOOm
II
-60
-I00
d
o
ioo
800
DislonceF•omCoast,km
[levelion
Pfecipilolion
,,,
[repelrent,ration ........
-,
•"
200
"• I
..........
"''"" .................
'""
'-' ............
u
. ..........
O0 m
O0m
IC)00m
III
d
ß
e*
'"ø1
o
•oo
•6o........ •6ø......
,;ac;'
' '
DislonceFromCoast,km
Fig. 3. Plot of &D versus distancefrom the PacificOcean of traversesI-III. Precipitationdata [Goodridge et al.,
1981], evapotranspirationdata [MacGillivray et al., 1975], and topographyare also shown. The segments,a, b, c, and
d and their regressioncurves(solidcurvesin the figures)are discussedin the text. Circled data pointsrepresentsamples
from thermal (temperature> 40øC)springs.
INGRAHAMAND TAYLOR:STABLEISOTOPE
SYSTEMATICS
OF HYDROLOGIC
REGIMES
83
TABLE 2. Analysisof Precipitation
Samples
Distance
From
Coast,
Amount of Rain
Collected or
DateCollected
Location
SnowDepth,cm
Traverse
8
12.7
30
37
45
73
March
March
March
March
31,
31,
31,
31,
1985
1985
1985
1985
5DsMow
/5•8OsMow
I
T16N/R1W/2
T16N/R1E/8
T17N/R3E/10
T18N/R4E/9
10.4
3.6
13.2
7.7
-54
-54
-70
-78
8.6
6.7
-89
-93
March 31, 1985
March 31, 1985
T33S/R5E/9, Ore
T37S/R7W/9, Ore
Nov. 11, 1984
Dec. 9, 1984
Jan. 20, 1985
March 31, 1985
T18N/RI7W/7
T18N/R17W/7
T18N/R17W/7
T18N/R17W/7
21.8
18
7
1.8P
-32
-60
-53
-72
Nov. 12, 1984
Dec. 9, 1984
Jan. 20, 1985
Dec. 9, 1984
Jan. 20, 1985
March 31, 1985
Jan. 20, 1985
March 31, 1985
Dec. 9, 1985
Jan. 20, 1985
March 31, 1985
Nov. 12, 1984
March 31, 1985
Nov. 12, 1984
Dec. 9, 1984
Jan. 19, 1985
March 31, 1985
Nov. 12, 1984
Dec. 9, 1984
Jan. 19, 1985
T16N/R13W/28
T16N/R13W/28
T16N/R13W/28
T15N/R9W/17
T15N/R9W/17
T15N/R9W/17
T15N/R8W/9
T15N/R8W/9
T15N/R6W/11
T15N/R6W/11
T15N/R6W/11
T15N/R5W/25
T15N/R5W/25
T15N/R5W/3
T15N/R5W/3
T15N/R5W/3
T15N/R5W/3
T15N/R4W/18
T15N/R4W/18
T15N/R4W/18
15.4
19.2
1.9P
19
4.9
25.9
8.7
26.8
23.1
6.6
26.8
17.9
17.1
8.1
14.1
3.6
15.6
5.8
8.5
3.9
-47
-76
-69
-75
-82
-73
-89
-83
-80
- 100
-78
-53
-78
-57
-76
-9.9
-81
-57
-80
-89
Nov. 11, 1984
Dec. 8, 1984
Jan. 19, 1985
March 30, 1985
Nov. 11, !985
T15N/R3W/18
T15N/R3W/I8
T15N/R3W/18
T15N/R3W/18
T16N/R2W/35
T16N/R2W/35
T15N/RIW/13
T15N/RIW/13
T15N/RIW/13
T15N/R4E/18
4.7
13.7
3.6
9.2
7.8
-65
-70
-83
-54
-62
3.9
2.9
7
13.1
4.3
9.1
5.2
-65
-55
-67
-62
-69
-75
-55
-72
10.6
3.2
13.5P
P
-70
-69
-58
-77
14.0
6.4
6.9P
7.1
12.8
18.3
-79
-81
-73
-79
-76
-72
49.3P
19.1
6.7
30.9
16.2
14.4
4.8
24.8
60.5
-76
-76
-95
-79
-75
- 77
-101
-80
-76
-7.3
-7.9
-10.1
-11.4
-13.0
-13.3
Traverse H, Rain
1
1
1
1
35
35
35
72
72
72
85
85
96
96
96
107
107
112
112
112
112
120
120
120
127
127
127
127
150
150
170
170
170
188
188
188
200
2O0
200
20O
210
210
210
210
221
221
221
221'
225
225
225
232
232
232
232
232*
Dec. 8, 1984
Nov. 11, 1984
Jan. 19, 1985
March 30, 1985
Nov. 11, 1984
Jan. 19, 1985
March30, 1985
Nov. 11, 1984
Dec. 8, 1984
Jan.19, 1985
March30, 1985
Nov. 11, 1984
Dec.8, 1984
Jan.19, 1985
March30, 1985
Nov. 11, 1984
Dec.8, 1984
March30, 1985
March31, 1985
Dec.8, 1984
Jan.19,1985
March30, 1985
Nov.11,1984
Dec.8, 1984
Jan.18,1985
March30, 1985
March30,1985
T15N/R4E/18
T15N/R4E/18
T16N/R5E/16
T16N/R5E/16
T16N/R5E/16
TI6N/R5E/16
T16N/R6E/33
T16N/R6E/33
T16N/R6E/33
TI6N/R6E/33
T16N/R7E/19
T16N/R7E/19
T16N/R7E/19
T16N/R7E/19
T16N/R8E/20
T16N/RSE/20
T16N/R8E/20
T17N/R8E/25
T17N/R8
E/25
T17N/R8E/25
T17N/R8E/25
T17N/RSE/25
-53
-8.7
-7.0
-8.1
-7.1
-11.2
-10.0
-11.8
-11.3
-10.8
-12.7
-12.7
-11.4
-12.0
-11.2
-10.0
-12.7
-10.2
-11.6
-13.4
-12.0
-9.8
-11.2
-9.7
-10.2
-11.4
-9.0
-10.6
-9.4
-9.5
-9.3
-10.6
-10.2
-9.3
-I1.3
-9.3
-12.6
-10.1
-10.2
-11.9
-11.0
-11.2
-12.0
-12.3
-11.3
-13.3
-11.8
-11.2
-7.1
-14.3
-12.8
-12.5
84
INGRAHAMAND TAYLOR:STABLEISOTOPESYSTEMATICS
OF HYDROLOGICREGIMES
TABLE 2.
Distance
From
(continued)
Amount of Rain
Collected or
Coast,
km
Date Collected
254
268
272
280
294
295
April
April
April
April
April
April
6,
6,
6,
6,
6,
6,
Snow Depth, cm
Location
Traverse H, Snow
T17N/R11E/30
T17N/R12E/30
T20N/R12E/15
T20N/R13E/11
T17N/RI5E/8
T19N/R15E/14
1985
1985
1985
1985
1985
1985
30.5
122
30.2
152
198
76
•DsMow
-73
-86
-97
-111
-108
-111
818OsM0W
-9.6
-12.1
-13.2
-15.2
-15.0
-14.7
P indicatesthat only a partial samplecouldbe collected.
*Year's sample.
closedsystemno geographicvariationin the isotopiccompositionof meteoricwateris observed(Figure7b) because
all precipitationis returnedto the atmosphere,andremixed.
progressively
depleted
inD and•80. A completely
"closed" The isotopicvariationsof the shallowgroundwateralonga
system results when all of the precipitation is returned to the stormtrack in a partially closedsystem(Figure 7c, which
atmosphereby evapotranspiration,and no geographicvari- maydisplaysomecurvature)reflecta depletionin deuterium
ation in the isotopic compositionof groundwateroccurs.In accordingto the relative magnitudesof precipitationlossas
evapotranspiration,the systemis said to be "open." In this
case all water leaves the system, and downwind precipitation and therefore shallow groundwater would then become
nature, neither end-member model is entirely obtained.
Deviation from the variation in $D with distance predicted
runoff and that returned via evapotranspiration.The impor-
by simpleRayleighfractionationis thereforean indicationof
a "partially closed" system,in which someevapotranspired
water is returned to the atmosphere and recycled. The
"degree of closure" of the system is governed by the
partitioningof precipitatedwater between runoff and evapotranspiration.Runoff removeswater from the cloud-ground
water system, while evapotranspirationretains water in the
(3D distancetrends) are developedin regions where precipitation dominatesevapotranspiration.
system by returning it to the atmosphere.
Figures7a-7c schematicallyillustratethe geographicvariation in 8D of the three specialsystemsas a functionof Fv,
the fractionof water vaporremainingin theatmospherefrom
the Rayleigh equation. An assumptionthat F•, varies in a
regularfashionwith distanceinland wouldrequirea regular
distributionof precipitationalong the traverse.The largest
isotopicvariationsoccur in an open systemdominatedby
Rayleighdistillation("rain out") Figure7a. In a theoretical,
-5O
-6O
-70
• -80
tant point here is that, at least qualitatively,steeperslopes
HydrologicSystemsin Californiaand Nevada
All of the isotopic variations characteristicof open and
closedhydrologicsystems(Figures7a-7c) are observedin
the hydrogenisotopedata of surfacewaters and shallow
groundwatersalongthetraverses.Consequently,
thehydrologicregimesare discussed
primarilyas examplesof open,
closed, and partially closed systems.
Open systems. The hydrologicregime of segmentI-a
seemsto most closelyapproximatean open system[Ingra-
ham and Taylor, 1986].The apparentvariation of /SDof
groundwaterin segmentI-a (Figure3) suggestsa dominance
of rain over evapotranspiration
(Figure 7a). The /SDof
precipitation
(Figure4) alsoindicatesa dominance
of rainout in this hydrologicsystem and suggestsa curvilinear
isotopicdepletiontrendsimilarto that observedfor surface
watersand shallowgroundwaters.
The dominanceof precipitationin thisfirstregimebasedon isotopicdatais supported
by the relativeproportionsof measuredprecipitationand
evapotranspiration.
Thecoastalsegments
of traverses
II and
III, althoughcharacterizedby 8D distancevariationswith
shallowerslopes, also suggestthat rain-out is relatively
important.However, precipitationand evapotranspiration
have relatively different magnitudesthan measuredin segment I-a. Althoughrain-outdominatesthese segments,they
-9O
are considered "partially closed."
Partially closedsystems. All of the coastalsegments
in
-lOO
the traverses across California are characterized by rela-11o
'"
0
ß
i "'
ß
20
'
i
40
ß
i
60
tively steep, linear trends for 8D of surfacewater and
ß
80
groundwaterversus distance, and although we have sug-
gested[Ingrahamand Taylor, 1986]that a curvedtrend
characterizessegmentI-a, some curvature might also be
suggested
for II-a (Figure3). In any case,the generallysteep
Fig. 4. Plotof 15Dof raincollected
between
January
20 and linearity rather than strongcurvatureof the first segment
March30, 1985,alongthefirst75 km of traverseI is shownwith
trendssuggestpartiallyclosedsystemswhere precipitation
respectto distancefromthe PacificOcean.
Distance
From
Coast, km
INGRAHAMAND TAYLOR: STABLEISOTOPESYSTEMATICSOF HYDROLOGICREGIMES
85
-2O
-3O
-4O
-50
107
35
112
-eo
120
•so
MWL
-7O
-80
-12
-10
-8
-4
-6
•180SMOW
-5O
MWL
-6O
150
200
-7O
72
112
225
221
232
210
-80
96
-90
b
-8
-9
-10
-11
-12
-13
-7
õ180
SMOW
-4O
MWL
-5O
-6O
200
-70
170
35
188
210
85
127
-9O
-1 oo
232
112
96
-11o
-16
c
-14
-12
-lO
.8
-6
580SMOW
Fig.5. Plotofthestable
isotopic
composition
ofprecipitation
collected
along
traverse
II: (a)November
11,1984,
(b)December
8,1984,
(c)January
18,!985,
and
(at)
March
30,1985.
Thenumbers
refer
tothelatitudinal
distance
from
thePacific
Ocean
in kilometers.
Thedatapoints
areconnected
ina fashion
chronologically
mimicking
a storm
asit
passes
across
thecoast
andinland
across
thestate.
Themeteoric
water
lineisalso
shown.
[{6
INGRAHAMAND TAYLOR:STABLEISOTOPESYSTEMATICS
OF HYDROLOGICREGIMES
200188
150/
•
-60
-70
221
MWL
210
225
-80
85
-90
3
-12
-11
-10
-9
-8
-6
-7
•180SMOW
Fig. 5.
(continued)
is partitionedbetween runoff and evapotranspiration(Figure
7c). Changesin the hydrologic regime by variations in the
relative proportions of precipitation and evapotranspiration
can produce different slopes for &D distance trends, as is
readily apparentfrom traverse II (Figure 3). Approximately
100 km inland, a marked decreasein slopein the &D distance
trend suggestsa decrease in precipitation relative to evapotranspiration. From 0 to about 100 km, the amounts of
precipitation and evapotranspiration are subequal, whereas
from !00 to about 225 km, evapotranspiration dominates
over precipitation. The amount of precipitation is inferred to
increase relative to evapotranspiration near 225 km inland
from the change in slope of the deuterium variation trend.
This inference is supportedby the precipitation and evapotranspirationdata plotted in Figure 3 traverseII. The general
validity of the isotopically based model describingthe relative precipitation/evapotranspiration
characteristicsof the
hydrologic regime thus appears to be borne out.
From approximately 100 to 280 km along traverse III
(Figure 3), evapotranspirationremains fairly constantand
DISTANCE-.PREClP
•D
RuNoFF
(a)
[F•DISTANCE---,
PRECIP
ET
•D
(b)
-30
-40
-50
ß.
-60
ß"-Fv DISTANCE....
mm
i,,
-70
PRECIP
-80
-90 -
(•D
ß
ET
m
-100
ß
ii
-110
m
-120
.
0
RUNOFF
i
50
ß
•
100
"' ß
i
150
ß
!
200
-
i
250
Distance From Coast, km
-' '
300
350
Fig. 7. Schematicof &Ddepletiontrendsfor atmosphericmoisture by rain-out for (a) a completelyopen system, (b) a closed
system, and (c) a partially closed system. Fv is fraction of water
Fig. 6. Plot of the weightedaverageof &D of rain (open vapor remainingin the "cloud system." In this model, Fv decreases
squares),snow(dividedsquares),
and surfacewaterand shallow as distanceand cumulativeprecipitationincreases.In a closed
groundwater
(solidsquares)
versusdistance
fromthePacificOcean system,Fv is constantbecausethere is no net water lossfrom the
collectedalongtraverse II.
atmosphere.
INGRAHAM
ANDTAYLOR:
STABLE
ISOTOPE
SYSTEMATICS
OFHYDROLOGIC
REGIMES
87
greater
thanprecipitation.
Accordingly,
theslopeof the
distance
trendis relativelylow. An increasein the precipitation/evapotranspiration
ratio about280km inlandapparently causesan increase in the slope of the •D distance
trend,eventhoughmeasuredprecipitationand evapotranspirationare indicatedto be of subequal
amounts.
Althoughthe mostimportantfactorcontrollingthe slope
of deuteriumdepletionin a partially closedsystemis the
ratio of precipitationto evapotranspiration,other factors
mustalsocontribute.Thesemay include(1) temperatureof
precipitation,
(2) the amountof water previouslyremoved
upwind,(3) modesof transpiration(e.g., type of transpiring
vegetation),(4) modesof evaporation(e.g., from eithersoil
ora free water surface),and(5) kineticisotopicfractionation
Winter
Rainy
Season
Winter Rainy Season=
2x SummerRainy
duringevaporation.
Closed systems. The final three segments of each
traverse,namelyI-c, II-d, and III-d (Figure3), representthe
hydrologicregimeof the Great Basin. At the westernboundary of the Great Basin a marked changein the slopeof
versusdistanceis apparentalongall traverses,althoughit is
mostpronouncedin traversesII and III. Traverse I showsa
moretransitionalchangein slope.The/SD valuesof groundwaters in the Great Basin are very similar within each
traversesegment,with virtually no distance-dependent
variation (Figure 7b). Most of the waters analyzed in the
segmentsl-c, II-d, and III-d are hot springs with long
recharge times and water sources at some distance (and
differentelevations)from the springs.As previously noted,
the similarity in /•D of these older waters with present-day
surface waters warrants their incorporation in the model
discussed here.
The low slope of/SD versus distance acrossmuch of the
Great Basin is compatible with the hydrologically closed
nature of the Great Basin. The low/SD value is accounted for
by the previous loss of most of the initial moisture by
precipitation. Only slight amounts of precipitation at this
stage in a regional Rayleigh distillation model for an eastward moving air mass would produce relatively large variationsin •D, especially if accompaniedby low condensation
temperatures.The isotopic data for segmentsl-c, II-d, and
III-d suggestthat this area tends to approximate both a
regionally and isotopically closed hydrologic system in
northern and central Nevada. The groundwater in the Great
and
Winter
Rahly
Season
Fig. 8. The geographicdominanceof the seasonalconcentration
of precipitation during 1951-1960. Precipitation is dominant in
winter on the west coast and during winter and summer in the
Southwest [after Markham, 1970]. Also shown is the location where
the ratio of the amount of winter to summerprecipitation is 2: 1
[after Horn and Bryson, 1960].
Nevada. Figure 8 illustrates the geographicareas in which
winterand/orsummerprecipitationdominates.In California, most of the precipitation occurs in winter, whereas in
the Southwest, precipitation occurs during both winter and
summer [after Markham, 1970]. A marked gradient in precipitation near the California-Nevada border is emphasized
by the isopleth[Horn and Bryson,1960]indicatinga 2 :. !
ratio of winter to summerprecipitation. This dual source of
atmosphericmoisture may be a contributory factor in controlling the relatively higher /SD of surface waters and
shallow groundwaters in the southern Great Basin. Th.e
isotopic effect and therefore contribution of summer-
dominatedprecipitationin the central and northernGreat
Basinis, for the most part, in isotopicequilibriumwith the Basin (segmentsI-c and II-d) appears to be small by com:
hydrologicsystemsupwind, as definedin Figure 7.
parison.
Comparison of the /•D values within the most inland
segmentsof traverses I, II, and III indicate that groundwaApplication to California's Water Balance
ters in the northern and central Great Basin have/SD values
between- 130and - 125,whereasgroundwaterin the southern Great Basin (segmentIII-d) has an average/SDvalueof
-110 (Figure3). Thus a slightnorth-southisotopicgradient
is apparentin the Great Basin. This gradientis primarilythe
result of the admixture of additional sourcesof atmospheric
moisturewith differentrain-out/evapotranspiration
histories.
Precipitationoccursin the southernGreat Basinduring
both summer and winter storms [Markham, 1970]. The
winter storms are a continuation of the eastward moving
fronts from the North Pacific Ocean. Winter storm path
trajectoriesacrossthe Sierra Nevada produceisotopicde-
pletionof the air massby rain-outaccentuated
by elevation
andtherelatedlowtemperatures
ofwinterprecipitation.
The
summerstormspassover the warm Gulf of California
[Hales, 1972, 1974]and more northwardacrosssouthern
The amount of terrestrial water recycled in a region can be
estimated from a simple precipitation/evapotranspiration
model. This model incorporated measuredhydrogen isotope
data on the coast, predicts the hydrogen isotope compositions above the crest of the Sierra Nevada after pseudoadiabatic cooling of eastward moving moisture, and demonstrates that recycled meteoric water is an important source
for inlandwaters. Further, the model developsa baselinefor
comparisonby calculatingthe total isotopic changeaccompanyingprecipitationin a completely open system. Several
simplifyingassumptionsin the model are (1) water contributed to the atmosphericvapor over the North Pacific Ocean
was originallyin isotopicequilibriumwith the oceanat 10øC,
(2) the atmosphereis vertically well mixed, (3) precipitation
occurs under equilibrium conditions, (4) precipitation con-
88
INGRAHAM
ANDTAYLOR:STABLEIbOTOPE
SYSTEMATICS
OF HYDROLOGIC
REGIMES
Traverse Tr
Altitude: 4000m
T:-17øC (a: 1.167)
Fv : 0.165
Altitude: ?_50m
T=7.5øC
(•=1.1005)
•ra
Crest
Nevada
Pacific
•
Coa
Pecific
Observed
;•
=120
per
mii
FvD
= 0.39
Ocean
Observed • D=-40perrail
Fv =0.66
Fig. 9. Diagram of the "lifting cloud" model is diagrammedfor traverse II. Observed hydrogen isotopic
compositionsof groundwaterat the coast is -40%0. Assuminga first precipitateover the ocean of 0%0,and a
condensation
temperatureof 7.5øC(alpha= 1.1005),an Fv for the cloudof 0.6 is determined.This cloudis then lifted
to 1500m abovethe Sierracrest(to 4000m) whereit condenses
out snowat -17øC (alpha= 1.167)with an F v of 0.17.
The cloud would now producea precipitateof-217%0. However, groundwaterat the crestis observedto have a &Dof
only - 120%•,whichcorresponds
(at - 17øC)to anFv of 0.39. The discrepancy
betweenthetwo F•, values(0.17and0.39)
is 0.22, which is interpretedto be the fractionof recycledwater requiredto producethe observedhydrogenisotopic
compositions of groundwater at the crest.
sists of rain at formation temperaturesabove 0øC, rain and
this "lifting cloud" calculation was also applied to traverses
snow between 0øC and -15øC, and snow below -15øC, and
I and II!, and the results are listed in Table 3.
(5) the isotopic compositionsof rain and snow represent
Storm systems crossing the coast contain between 60%
conditionsat 250 and 1500m, respectively,abovethe ground (Fv = 0.60, traverse I) and 70% (Fv = 0.70, traverse III) of
surface.
This model and results of calculations for traverse II are
shown in Figure 9. Because water evaporated from the
ocean yields a precipitate with a &D value of close to 0,
significantprecipitationfrom the stormtrack prior to reaching !and is required to explain the &D values of -40 at the
beginningof traverse I!. The fraction of initial water vapor
remainingin the cloud system(Fv) is 0.66 from the Rayleigh
equation. As the eastward moving storm clouds rise
pseudoadiabaticallyto the crest of the Sierra Nevada, they
lose water along the way, further depleting the atmosphere
in deuterium. In a simple rain-out process the predicted
isotopic composition of precipitation (snow) at the crest is
3D = -217, as shown for traverse II in Figure 9. Similarly,
TABLE 3.
the original water vapor, based on the 8D of coastal groundwaters. Mixing ratios (in grams of water per kilogram of dry
air) and saturatedtemperatureswere calculatedfor Fv = 1.0
(inception of storm) to evaluate whether the assumptionof
30-40% water loss over the ocean is reasonable. The result-
ing saturation temperatures were between 12.5øC and 15øC
(Table 3). The predicted &D and F•, values for snow at the
Sierra Nevada crest by this "lifting cloud" model are given
with the measured &D value of ground water at the crest in
Table 3. Values of Fv calculatedfrom the Rayleighequation
constrained by the measured •D values are lower by comparison; a result of water recycling as described below.
The discrepanciesin F• and between predicted and measured 3D values for each traverse listed in Table 3 imply
Calculation of Fv at the Sierra Nevada Crest
Traverse
Parameters
Method
observed &D of groundwater at the coast (%0)
calculatedFv at the coast
mixing ratio at Fv = 1.0 (inception of storm)
saturationtemperature at Fv = 1.0
elevation at the Sierra Nevada crest, m
altitude of precipitation formation at the crest, m
temperature of precipitationformation at the crest
fractionation
factor
a at the crest
predicted 3D of precipitationat the crest, %0
Fv at the crestby pseudoadiabatic
calculations
observed 3D of meteoric water at the crest, %0
Fv neededto producethe observed&D at the crest
Discrepancyin Fv betweenobservedand calculated
I
-50
0.60
10.8
15øC
2100
3600
- 14oC
1.158
-194
0.19
-120
0.37
0.18
II
-40
0.66
9.75
13øC
2500
4000
- 17oC
1.167
-217
0.17
-120
0.39
0.22
III
-33
0.70
9.0
12.5øC
4400
5900
-32øC
1.204
-379
0.06
-125
0.45
0.39
•D (amount of water recycled)
F,, fractionof watervaporremaining
in thecloudsystem;
I, waterlosscalculated
by psuedoadiabatic
means;
2, waterlosscalculated
by measurements
of the hydrogen
isotopiccompositions
of groundwater
at the crest.
INGRAHAM AND TAYLOR: STABLEISOTOPESYSTEMATICSOF HYDROLOGICREGIMES
upwind
recycling
by evapotranspiration.
Differences
in Fv
vary between0.18 and 0.39, and the differencesin 8D
predicted
forprecipitation
at thecrestof theSierraNevada
89
Craig, H., isotope variations in meteoric waters, Science, 133,
1702-1703, 1961.
Dansgaard,W., Stableisotopesin precipitation,Teltus,16,436-438,
1964.
rangefrom 74 to 254%o.Although minor changesin the Dugan,J.P., Jr., J. Borthwick,R. S. Harmon, M. A. Gagnier,J. E.
differenceswould result from adjustingthe initial assumpGahn, E. P. KinseI, S. Macleod, J. A. Viglino, and J. W. Hess,
Guanidinehydrochloridemethodfor determinationof water oxytionsof tempera.ture,
elevationof isotopicequilibrium,etc,it
is evident that isotopic variations associatedwith rain-out
are moderated by recycling. The recycling processwould
alsoprobablyincludethe evaporationof rain duringdescent
andpartialevaporationof meltwaterpriorto infiltration.
CONCLUSIONS
gen isotoperatios and the oxygen-18fractionationbetween carbon dioxideand water at 25øC,Anal. Chem., 57, 1734-1736, 1985.
Epstein,S., andT. K. Mayeda,Variations
on !80 contents
of
waters from natural sources, Geochim Cosmochim Acta, 4,
213-214, 1953.
Friedman,I., and J. O'Neil, Data of geochemistry,compilationof
stableisotopicfractionationfactorsof geochemicalinterest,U.S.
The hydrogenisotopecompositionsof individualprecipita-
Geol. Surv. Prof. Pap., 440KK, 1977.
Friedman, I., and G. I. Smith, Deuterium content of snow cores
from Sierra Nevada area, Science, 169, 467-470, 1970.
Friedman, I., and G. I. Smith, Deuterium content of snow as an
index to winter climate in the Sierra Nevada area, Science, 176,
tion events were found to be highly variable and not representativeof the average hydrogen isotope composition of
Friedman, I., A. C. Redfield, B. Shoem, and J. Harris, The
Groundwater, surface water, and precipitation were collected along three traverses, aligned parallel to the atmo-
spheric
flowpath, acrossnorthernCaliforniaandNevada.
790-793, !972.
variations of the deuterium content of natural waters in the
precipitation.However, the weightedyearly averageof
hydrologiccycle, Rev. Geophys.,2, 177-224, 1964.
precipitation
more accuratelyreflectsthe nature of the Goodridge,J. D., K. Jones,W. Mancibo, C. K. Muir, D. Schuder,
hydrologicregime, as representedby the 8D values of
E. W. Danley, P. Schreiner,E.G. Bingham,and S. Midson,
shallowgroundwater.
The traverses were divided into distinct segments based
on the variations in •iD of surface water and shallow groundwater. Variations of 8D within chosen segments indicate
Californiarainfallstudy,monthlytotal precipitation1849-1980,41
pp., Calif. Dep. of Water Resour., Sacramento, 1981.
Hales,J. E., Jr., Surgesof maritimetropicalair northwardover the
hydrologicregimesthat correlatewith relativedifferencesin
Gulf of Mexico or PacificOcean,J. Appl. Meteorol., 13, 331-342,
the vertical fluxes of meteoric water estimated from mea-
suredevapotranspirationand precipitationdata. The roughly
linear trends of 8D versus distance of most segmentsapprox-
imate partially closed systems in which precipitationis
partitioned
betweenrunoffandevapotranspiration.
Different
slopesof thesetrends,for the mostpart, representdifferent
relative contributions of evapotranspirationand precipitation. One coastal segment appears to closely representan
opensystemwhere precipitationis greaterthan evapotranspiration,and water is removedvia runoff.
Partially closed systemsrequire terrestrial recyclingof
meteoricwater by evaporationand transpirationto explain
the geographicvariationin/SD of inlandmeteoricwater. A
gulf of California,Mon. WeatherRev., I00(4), 298-306, 1972.
Hales, J. E., Jr., Southern United States summer monsoon source1974.
Horn, L. H., and R. A. Bryson, Harmonic analysisof the annual
marchof precipitationover the United States,Ann. Assoc.Am.
Geog., 50, 157-171, 1960.
Ingraham,N. L., and B. E. Taylor, Hydrogenisotopestudyof
large-scalemeteoricwater transportin Northern Californiaand
Nevada, J. Hydrol., 85, 183-197, 1986.
Jacobson,R. L., N. L. Ingraham, and M. E. Campana, Isotope
hydrologyof a BasinandRangegeothermalsystem,Publ.41807,
Desert Res. inst., Univ. of Nev., Las Vegas, 1983.
Kendall, C., and T. Coplen, Multisample conversionof water to
hydrogenby zincfor stableisotopedetermination,
Anal. Chem.,
57, 1437-1440, 1985.
MacGillivray,N. A., R. R. McGill, J. H. Lawrence,F. E. Stumpf,
R. D. Smith, C. K. Muir, W. G. McKane, T. Latham, and J. D.
Goodridge,Vegetativewateruse in California,1974,Bull. 113-3,
simplemodel suggestsabout 20% terrestrialmoistureis
104pp., Calif. Dep. of Water Resour., Sacramento,1975.
recycledvia evapotranspiration
acrossnorthernandcentral Mariner, R. H., T. S. Presser,J. B. Rapp, and L. M. Willey, The
California.
minor and trace elements,gas, and isotope compositionsof the
principalhot springsin Nevada and Oregon,U.S. Geological
Theisotopiccomposition
of meteoricwateris shownto be
directlyrelatedto the closureof the hydrologicsystem(s) Survey Open File Rep., 1975.
upwind.A smallchangein the "degreeof closure"of the Mariner, R. H., T. S. Presser,and W. C. Evans, Geochemistryof
activegeothermal
systems
in northernBasinandRangeprovince,
hydrologic
system(i.e., a changein therelativeamounts
of
Spec.Rep. 13, pp. 95-119,GeothermalResour.Counc.,Davis,
precipitation
and runoffor evapotranspiration)
upwindmay
Calif., 1983.
producesubstantial
changesin the isotopiccomposition
of Markham, C. G., Seasonalityof precipitationin the United States,
Ann. Assoc.Am. Geogr., 60, 593-597, 1970.
Mer!ivat, L., and J. Jouzel, Global climatic interpretationof the
deuterium-oxygen-18
relationshipfor precipitation,J. Geophys.
Acknowledgments.
Thisresearchwassupported
by the State
inland meteoric
water.
Res., 84, 5029-5033, 1979.
WaterResources
Research
Institute,project569986-28558-3,
andby
the Universityof CaliforniaWater ResourcesCenter,project Reed, M. J., Chemistryof thermal waters in selectedgeothermal
UCAL-WRC-W-656.Additionalfundingwas providedby a Grant-
areasof California, Rep. TR-15, Calif. Div. of Oil and Gas, San
Francisco, 1975.
in-Aidof Research
fromSigmaXi. J. R. O'Neil(U.S.G.S.,Menlo
Park,California)
kindlypermitted
useof themassspectrometer
for Rozanski,K., Deuteriumand oxygen-18in Europeangroundwahydrogen
isotope
analyses,
andJ. Hess(Desert
Research
Institute, ters-Links to atmosphericcirculationin the past, Chem. Geol.,
52, 349-363, 1985.
LasVegas,Nevada)alloweduseof theDRI isotope
laboratory
for
some
of theoxygen
isotope
analyses.
T. Coplen
(U.S.G.S.,Reston, Rozanski,K., K. O. Munnich,and C. Sonntag,Modellingof stable
of atmosphericwater vapourand precipitaVirginia)kindlysuppliedseveralduplicate
oxygenandhydrogen isotopecomposition
isotopeanalyses.
REFERENCES
Bige!eisen,
J., M. L. Perman,and H. Prosser,
Conversion
of
hydrogenic
materials
to hydrogen
for isotopic
analysis,
Anal.
Chem., 24, 1356-1357, 1952.
tion in StableIsotopes,editedby H. L. Schmidt,H. Foerstel, and
K. Heinzinger,Elsevier, New York, 1982a.
Rozanski,K., C. Sonntag,and K. C. Munnich, Factorscontrolling
stableisotopecompositionof Europeanprecipitation,Tellus,34,
142-150, 1982b.
Salati,E., A. Dall'Olio, E. Matsui, andJ. R. Gat, Recyclingof water
90
INGRAHAMANDTAYLOR:STABLEISOTOPE
SYSTEMATICS
OF HYDROLOGIC
REGIMES
in the Amazon basin:An isotopicstudy, WaterResour.Res., 15,
1250-1258, 1979.
Smith, G.I., I. Friedman, H. Klieforth, and K. Hardcastle, Areal
gativeresultsthroughmid-1983,U.S. GeologicalSurveyWater
ResourcesInvest. Rep., 84-4267, 1984.
N. L. Ingraham, Water ResourcesCenter, Desert Research
distributionof deuteriumin easternCaliforniaprecipitation,1968Institute,Universityof Nevada,2505ChandlerAvenue,Las Vegas,
1969, J. App. Meteorol., 18, 172-188, 1979.
Truesdell, A. H., M. Nathenson, and R. O. Rye, The effects of NV 89120.
B. E. Taylor, GeologicalSurveyof Canada,601 BoothStreet,
subsurfaceboiling and dilution on the isotopiccompositionof
Yellowstone thermal waters, J. Geophys. Res., 82, 3694--3703, Ottawa, Ontario, K1A 0ES, Canada.
1977.
Yonge, C. J., L. Goldberg,and H. R. Krouse,An isotopicstudyof
water bodies along a traverse of SouthwesternCanada, J. Hydrol., 106, 245-255, 1989.
Waddell, R. K., J. H. Robinson,and R. K. Blankennagel,Hydrology of Yucca Mountain and vicinity, Nevada-Californiainvesti-
(Received March 27, 1989;
revised May 21, 1990;
acceptedJune 23, 1990.)