Presentation given during the USGS/IAEA/IW:LEARN groundwater learning exchange in the US April 14-26, 2007. L. Niel Plummer U.S. Geological Survey, Reston, Virginia Ward Sanford, Laura Bexfield and Scott Anderholm

1. U.S. Department of the Interior
U.S. Geological Survey
Use of Chemical and Isotopic Data to Improve Conceptualization of
Groundwater Flow in the Middle Rio Grande Basin, NM
L. Niel Plummer
U.S. Geological Survey, Reston, Virginia
Ward Sanford, Laura Bexfield and Scott Anderholm

2. Thanks
USGS folks (Reston, Menlo Park, Albuquerque) for field assistance,
laboratory analyses, data processing, drafting, manuscript
preparation:
Ed Busenberg, Jerry Casile, Mike Doughten, Julian Wayland, Peggy
Widman, Andrew Stack, Anne Burton, Brian C. Norton, David Jones, Ami
Mitchell, Daniel Webster, Tyler Coplen (and RSIL staff), Kinga Revesz,
Robert L. Michel, Fred Gebhardt, R.K. DeWees, Jim Bartolino, Joe
Sterling, Carolina Trevizo, and Lori Shue.
Advice: Doug McAda, Mark Hudson, and Scott Minor of the USGS, Fred
Phillips of New Mexico Institute of Mining and Technology, and John
Hawley and Sean Connell of the New Mexico Bureau of Geology and
Mineral Resources (NMBGMR).
Colleague/Peer Review: Jim Bartolino, Don Thorstenson, Tom Reilly,
Pierre Glynn, John Izbicki.
Funding: Ground Water Resources Program and the National Research
Program of the U.S. Geological Survey.

3. U.S. Department of the Interior
U.S. Geological Survey
Acknowledgments
This study would not have been possible without the generous assistance of
individuals from the following organizations:
• Cochiti, Isleta, Jemez, Sandia, San Felipe, Santa Ana, Santo Domingo, and Zia Pueblos
• The Southern Pueblos Agency
• The Bureau of Indian Affairs
• The U.S. Forest Service
• The Bureau of Land Management
• The U.S. Fish and Wildlife Service
• Kirtland Air Force Base
• Sandia National Laboratories
• The New Mexico Office of the State Engineer
• The New Mexico Environment Department
• The University of New Mexico and New Mexico Tech, including the NMBGMR
• The City of Albuquerque Environment Department and Water Utilities Division
• The City of Belen and the Town of Los Lunas
• Rio Rancho Utilities, Rio Grande Utilities, Sandia Peak Utility Company, National Utilities, New Mexico
Utilities, DRESCO, Intel, AT&T, King Brothers Ranch, and the Huning Ltd. Partnership
• Individual home owners.
• The USGS, and any others I may have forgotten….

4. Middle Rio Grande Basin Study
Middle Rio Grande Basin Study

5. •Covers over 7,800 km2
•Located within the
Basin and Range
physiographic
province and the Rio
Grande Rift
•Defined by the extent
of Cenozoic deposits
Middle Rio
Grande
Basin

6. Features of the
Middle Rio Grande
Basin
• Average elevation exceeds
1,500 m, with surrounding
mountains approaching 3,300
m.
• Semi-arid climate with
variable precipitation
resulting mostly from
summer storms.
• Rio Grande and associated
irrigation system inset in a
terraced valley.
• Major tributaries are
ephemeral streams and
arroyos.

7. Precipitation at Albuquerque
Rio Grande Discharge

8. Land Use
Mullins and Hare, 1999
•Primarily rangeland
•Irrigated agriculture
dominates areas of inner
valley that are not urban.
•Albuquerque and Rio
Rancho form the main
urban areas.
•Population increased
almost 120% between 1970
and 2000, to about 690,000
people.

9. Sources of Recharge: 1. Along/near basin margins
Mountain-front processes, arroyo infiltration, and
subsurface ground-water inflow
Photo by J.R. BartolinoPhoto by Niel Plummer

10. Sources of Recharge: 2. Rio Grande
In central parts of the basin, recharge occurs along the
Rio Grande, tributaries, and irrigation canals.
Areal recharge is negligible.
Rio Grande Canals
Photos by J.R. Bartolino

11. Santa Fe Group Aquifer System
Bartolino and Cole (2002)
• Consists of generally
unconsolidated to
moderately consolidated
basin-fill sediments up to
4,300 m thick.
• Includes Santa Fe Group
deposits of Oligocene to
middle Pleistocene age,
plus overlying Quaternary
sediments.
• Broadly divided into three
units, of which the upper
unit is the most productive.
• Aquifer conditions are
generally unconfined (semi-
confined at depth).

17. http://www.cabq.gov/waterresources/pdfs/Secure.pdf

18. http://www.cabq.gov/waterresources/index.html

19. Bexfield and Anderholm, 2002
2002 water-level
contours and declines
from predevelopment
• Substantial pumping since about
1950 has altered predominantly
north-south flow of ground water.
• Ground water (until recently)
supplied all drinking water.
• During the 1990s, basin-wide
pumping was about 200 million
m3
annually; about ¾ of this was
pumped by the City of
Albuquerque.
• Past 40 years, water-level
declines of more than 40 m.

20. Multi-agency Middle Rio Grande Basin Study
• Major participants: USGS (NRP, WRD, GD, NMD), UNM, NMIMT, New
Mexico Bureau of Geology and Mineral Resources, New Mexico Office
of the State Engineer, City of Albuquerque
• Major investigations:
– Detailed geologic mapping and high-resolution airborne geophysics
to better characterize faults and hydrologic properties
– Use of environmental tracers to quantify mountain-front recharge,
characterize river-aquifer interaction, and improve knowledge of the
flow system
– Ground-water-flow modeling
The U.S. Geological Survey (USGS) Middle Rio Grande Basin Study was a 6-
year effort (1995-2001) by the USGS and other agencies to improve the
understanding of the hydrology, geology, and land-surface characteristics of the
Middle Rio Grande Basin in order to provide the scientific information needed for
water-resources management. The Santa Fe Group aquifer system has
historically been the main source of municipal water for the region, and the main
purpose of the study was to improve the understanding of the water resources of
the basin.

21. U.S. Department of the Interior
U.S. Geological Survey
• Sources of recharge
• Ground-water flow paths
• Ground-water travel times
• Variability in characteristics with
depth
• Historical recharge rates
Objectives of geochemical characterization
Use chemical and isotopic data to better understand certain
aspects of the ground-water flow system, including:

22. U.S. Department of the Interior
U.S. Geological Survey
Methods: Ground-water chemistry
• Collected samples from nearly 300 wells and springs
– Sampled wells of all types (domestic, municipal, monitoring, stock)
– Wells ranged in depth from 7 to 615 meters
• Analyzed ground-water samples for:
– Concentration of 30 major, minor, and trace elements
– Isotopic composition of water (2
H and 18
O)
– Isotopic composition of dissolved inorganic carbon (13
C and 14
C)
– Isotopic composition of dissolved sulfate (34
S)
– Tritium content (3
H) and tritium/helium-3 ratio (3
H/3
He)
– Concentration of dissolved atmospheric gases, including nitrogen,
argon, helium, chlorofluorocarbons (CFC’s), and sulfur hexafluoride
• Retrieved historical ground-water data from USGS and City of
Albuquerque databases

23. U.S. Department of the Interior
U.S. Geological Survey
Methods: Surface-water chemistry
• Sampled surface-water sites monthly for up to 2 years
– Rio Grande and associated irrigation canals, ground-water drains
– Larger tributaries: Jemez River and Rio Puerco
– Arroyos: Tijeras, Abo, and Bear Canyon
• Analyzed surface-water samples for:
– Major, minor and trace elements (30)
– 2
H and 18
O
– CFC’s
– Tritium content
– 13
C and 14
C (once)

25. 1 9 9 7 1 9 9 8 1 9 9 9
Y E A R
- 1 0 0
- 9 0
- 8 0
- 7 0
- 6 0
δ2
H,INPERMIL
E X P L A N A T IO N
R io G r a n d e
R io G r a n d e d r a i n s , c a n a ls
B e a r C a n y o n A r r o y o
E m b u d o S p r in g
T ije r a s A r r o y o
-77
-84
-90
δ2
H o
/oo

26. - 1 4 - 1 2 - 1 0 - 8 - 6 - 4
δ 1 8
O , IN P E R M IL
- 1 0 0
- 8 0
- 6 0
- 4 0
δ2
H,INPERMIL
E X P L A N A T IO N
R io G r a n d e
R io G r a n d e d r a in s , c a n a ls
B e a r C a n y o n A r r o y o
E m b u d o S p r in g
T ije r a s A r r o y o
J e m e z R iv e r
J e m e z R . b e lo w
J e m e z C a n y o n D a m
R io P u e r c o
GlobalM
eteoric
W
aterLine
δ 2
H = 8 .1 5 δ 1 8
O + 9 .0
( le a s t s q u a r e s f it )

27. Pre-development
water levels and
implied directions
of groundwater flow
• Generally N to S
• Groundwater trough
• Relation to faults

28. Dissolved Oxygen, mg/L Specific Cond. uS/cm

29. Sodium, mg/L Alkalinity as HCO3, mg/L

30. - 1 6 - 1 2 - 8 -4
D e lt a O - 1 8 (p e r m il)
- 1 2 0
- 1 0 0
- 8 0
- 6 0
- 4 0
- 2 0
DeltaD(permil)
A ll S a m p le s , M R G B
D = 7 .6 O - 1 8 + 2 .4
n = 3 3 5
Groundwater only

34. - 1 2 0 - 1 0 0 - 8 0 - 6 0 - 4 0 - 2 0
δ 2
H , IN P E R M IL
1 ,6 0 0
1 ,2 0 0
8 0 0
4 0 0
0
DEPTHBELOWWATERTABLE,INFEET
E X P L A N A T I O N
P IE Z O M E T E R N E S T S
A , L in c o l n
E , W e s t B lu f f
F , 9 8 t h S t ., 1 9 9 8
G , Is le t a
H , S ie r r a V i s t a
I, N o r E s t e
J , M a t h e s o n
K , M e s a D e l S o l, 1 9 9 8
L , M o n t a ñ o 6
N , G a r f ie l d
O , H u n t e r R id g e
P , S i s t e r C it ie s
Q , D e l S o l, 1 9 9 7
Q , D e l S o l, 1 9 9 8
R , M o n t e s a
S , S a n d ia
T , T o m e
R io G r a n d e
w in t e r /s p r in g
1 9 9 7 - 9 9
F
K
I
J
S
A

35. Key Chemical and Isotopic Indicators of Water Source
• Majors—Sp. Cond., Ca, Mg, Na, K, Cl, SO4, HCO3
• Minors—Silica, B, V, U, As, F, NO3
• Isotopes—D, 18
O, 13
C, 14
C, 34
S, 3
H
• Gases—N2, Ar, He, CFCs, SF6

37. - 1 6 - 1 4 - 1 2 - 1 0 - 8 - 6
δ 1 8 O , IN P E R M IL
- 1 2 0
- 1 0 0
- 8 0
- 6 0
- 4 0
δ2
H,INPERMIL
G lo b a l M e t e o r ic W a t e r L in e
δ 2
H = 7 .6 2 δ 1 8
O + 2 .4 8
δ 2
H = 8 δ 1 8
O + 1 0
N o r t h w e s t e r n
z o n e
W e s t - C e n t r a l z o n e
W e s t e r n B o u n d a r y z o n e
N o r t h e r n M o u n t a in
F r o n t z o n e
A b o A r r o y o z o n e
E a s t e r n M o u n t a in
F r o n t z o n e
T ije r a s F a u lt Z o n e z o n e
T ije r a s A r r o y o z o n e
R io P u e r c o z o n e
S o u t h w e s t e r n M o u n t a in F r o n t z o n e
N o r t h e a s t e r n z o n e
C e n t r a l
z o n e D is c h a r g e z o n e

40. Tritium
A r r o y o
Calabacillas
T i j e r a s
Grande
Rio

41. SF6

42. CFC-12
A r r o y oCalabacillas
T i j e r a s
Grande
Rio

43. W a t e r T a b le
0 2 0 4 0 6 0 8 0 1 0 0
C F C - 1 2 C o n c e n t r a t io n in p g /k g
1 6 0 0
1 2 0 0
8 0 0
4 0 0
0FeetBelowWaterTable
W e ll N e s t
M o n t a n o 6
D e l S o l '9 7
G a r f ie ld
H u n t e r s R id g e
W e s t B lu f f
9 8 t h S t . '9 8
D e l S o l '9 8
I s l e t a
L in c o l n
M a t h e s o n
M e s a D e l S o l '9 8
M o n t e s a
S is t e r C i t ie s
S a n d i a
S ie r r a V is t a
N o r E s t e
T o m e ( D e e p )
M a t h e s o n
9 8 t h
S t r e e t
S a n d ia
T o m e
I s le t a

44. 0 1 0 2 0 3 0
T R IT IU M C O N C E N T R A T IO N ,
IN T R IT IU M U N IT S
0
4 0
8 0
1 2 0
1 6 0
2 0
6 0
1 0 0
1 4 0
14CACTIVITY,
INPERCENTMODERNCARBON
E X P L A N A T IO N
H Y D R O C H E M IC A L Z O N E
N o r t h e r n M o u n t a in F r o n t
N o r t h w e s t e r n
W e s t - C e n t r a l
E a s t e r n M o u n t a in F r o n t
C e n t r a l
0 .1 1 1 0 1 0 0 1 ,0 0 0 1 0 ,0 0 0 1 0 0 ,0 0 0
C F C - 1 2 C O N C E N T R A T I O N ,
IN P IC O G R A M S P E R K IL O G R A M
0
4 0
8 0
1 2 0
1 6 0
2 0
6 0
1 0 0
1 4 0
14
CACTIVITY,
INPERCENTMODERNCARBON
1 0 2 p m C
9 5 p m C
A .
M o d e r n C F C - 1 2
Pre-Bomb Ao
for Radiocarbon Dating is near 100 pmc

45. 0 1 0 0 2 0 0 3 0 0
C F C - 1 2 C O N C E N T R A T I O N ,
I N P I C O G R A M S P E R K I L O G R A M
0
4 0
8 0
1 2 0
1 6 0
2 0 0
14
CACTIVITY,
INPERCENTMODERNCARBON
1 0 0 p m C
1 9 5 9
1 9 6 4
1 9 6 9
1 9 7 4
1 9 7 9
1 9 8 5
1 9 9 7

46. Determination of 14
C ages in the MRGB
• Ao determined to be 100 pmC
• 13
C, a stable isotope affected by
phase changes and chemical
reactions, indicated that
reactions involving carbon
were minor
• Redox reactions associated
with oxidation of organic
matter were not important
• Processes that were modeled
included evaporation, mixing,
cation exchange, and phase
changes involving calcite,
plagioclase feldspar, silica,
kaolinite, gypsum, and CO2
R a d io c a r b o n D a t in g i n N E T P A T H
B
A n d
A o b s
( C a lc )A ( M o d e le d o r M e a s u r e d )o
A
∆ t ( y e a r s )
5 ,5 6 8
ln 2
ln=
A
A
n d
o b s
R e a c t io n M o d e l
A + R e a c ta n t s B + P r o d u c ts
A o A n d
U.S. Department of the Interior
U.S. Geological Survey

47. 0 2 0 4 0
U n a d ju s te d R a d io c a r b o n A g e (k a )
0
1 0
2 0
3 0
NumberofSamples
A ll S a m p le s
M id d le R io G r a n d e B a s in

49. D
F
C
B
A
J
KG
PE
R
O
H
I
M
Q
L
N
Lower gradients
west of RG
Higher gradients
east of RG
Ages at water
table increase
with distance
of flow into
basin.

51. 0 5 1 0 1 5 2 0 2 5
R A D I O C A R B O N A G E , I N T H O U S A N D S O F Y E A R S
3 0 0
2 0 0
1 0 0
0
MID-DEPTHBELOWWATERTABLE,INMETERS
E a s t e r n M o u n t a i n F r o n t
A lb u q u e r q u e v ic in it y
S o u t h o f T ije r a s A r r o y o
N o r t h o f A lb u q u e r q u e

52. 0 1 0 ,0 0 0 2 0 ,0 0 0 3 0 ,0 0 0
R A D IO C A R B O N A G E , IN Y E A R S
- 1 0 8
- 1 0 4
- 1 0 0
- 9 6
- 9 2
- 8 8
δ2H,INPERMIL
P a le o R io G r a n d e W a t e r
C e n t r a l Z o n e

53. 0 1 0 ,0 0 0 2 0 ,0 0 0
R A D IO C A R B O N A G E , IN Y E A R S
- 1 1 0
- 1 0 0
- 9 0
- 8 0
- 7 0
- 6 0
δ2H,INPERMIL
E X P L A N A T IO N
C e n t r a l z o n e
E a s t e r n M o u n t a in F r o n t z o n e

54. 0 5 0 0 0 1 0 0 0 0 1 5 0 0 0 2 0 0 0 0 2 5 0 0 0
C a le n d a r Y e a r s ( B P )
0
5 0 0 0
1 0 0 0 0
1 5 0 0 0
2 0 0 0 0
2 5 0 0 0
RadiocarbonYears

55. 0 1 0 2 0 3 0 4 0 5 0
R A D IO C A R B O N A G E , IN T H O U S A N D S O F Y E A R S
- 2
0
2
4
6
CORRECTIONTOCALENDARYEARS,
INTHOUSANDSOFYEARS
z o n e s 3 - 4
z o n e s 1 0 , 1 2
z o n e s 1 , 2 , 5 - 9 , 1 1

56. Model calibration included:
Radiocarbon ages and
location of some hydro-
chemical zone boundaries.

57. Some changes to conceptualization of groundwater
flow based on chemical and isotopic data
• Basin-wide recharge
rate 170x106
m3
/yr.
• Water flowed from
mts to R.G. at Albuq.
• GW Trough is a zone
of high transmissivity.
• Time-scale of gw
system unknown.
• Recharge rate is only
about 22x106
m3
/yr.
• Water beneath Albuq.
is from R.G. to the N.
• GW Trough due to a
transient in RC rate.
• GW sampled on the
0-40 ka time-scale.
Before After

58. Some changes to conceptualization of groundwater
flow based on chemical and isotopic data (cont.)
• Some sources of
water recognized.
• Zone boundaries
poorly known.
• Nothing known about
depth variations.
• Paleo-recharge not
investigated.
• 12 sources and one
discharge mapped.
• Zone boundaries
used to calib. model.
• Chem., isotopic and
age gradients meas.
• Many aspects of
paleo-recharge
characterized.
Before After

59.  Long-term reliability and sustainability
 Protection of valued resource
 Project viability
 Ability to support quality of life
 Financial feasibility
Initiated in 1997

60. Curtailment Strategy
The Albuquerque Bernalillo County Water Utility
Authority has made a commitment to shut down
the system involving the dam when flows are less
than 130 cubic feet per second. This is consistent
with the Authority’s strategy to utilize the aquifer
as a drought reserve during times of very low
surface water supply. Under normal
circumstances, there will be a one-to-three inch
difference in the water level upstream and
downstream of the dam, hardly noticeable in a
600-foot-wide river. Curtailing or completely
shutting diversions is also the Authority’s
commitment to protect fish and wildlife and the
Bosque during low flows. During droughts we will
stop releasing San Juan-Chama water from
Abiquiu and will utilize ground water. When flows
return to normal the following winter, the stored
San Juan-Chama water will be treated and placed
back into the aquifer (Aquifer Storage Recovery)
to assist in balancing the amount removed during
the drought.

62. How will this research be used?
• Improved understanding of
extent of non-renewable
resource.
• Improved understanding of
the severity of the water-
availability need in the region.
• Improved understanding of
modern recharge rate
(lowered estimate of
renewable groundwater).
• Improved hydrogeologic data
for future refinement of a
regional ground-water model
to help manage the resource
(not yet done).

63. List of publications from Middle Rio Grande Basin geochemical study
Plummer, L.N., Bexfield, L.M., Anderholm, S.K., Sanford, W.E., and Busenberg, E., 2001, Geochemical characterization of ground-water
flow in parts of the Santa Fe Group aquifer system, Middle Rio Grande Basin, New Mexico, in Cole, J.C., ed., U.S. Geological Survey
Middle Rio Grande Basin Study -- Proceedings of the Fourth Annual Workshop, Albuquerque, New Mexico, February 15-16, 2000: U.S.
Geological Survey Open-File Report 00-488, p. 7-10.
Sanford, W.E., Plummer, L.N., McAda, D.P., Bexfield, L.M., and Anderholm, S.K., 2001, Estimation of hydrologic parameters for the
ground-water model of the Middle Rio Grande Basin Using carbon-14 and water-level data, in Cole, J.C., ed., U.S. Geological Survey
Middle Rio Grande Basin Study -- Proceedings of the Fourth Annual Workshop, Albuquerque, New Mexico, February 15-16, 2000: U.S.
Geological Survey Open-File Report 00-488, p. 4-6.
Bexfield, L. M., and Plummer, L. N., 2003, Occurrence of arsenic in ground water of the Middle Rio Grande Basin, central New Mexico, in
Welch, A. H., and Stollenwerk, K. G., eds., Arsenic in Ground Water: Geochemistry and Occurrence, Kluwer Academic Publishers, Chapter
11, p. 295-327.
Plummer, L. Niel, Bexfield, Laura M., Anderholm, Scott K., Sanford, Ward E., and Busenberg, Eurybiades, 2004, Geochemical
characterization of ground-water flow in the Santa Fe Group aquifer system, Middle Rio Grande Basin, New Mexico. U.S. Geological
Survey Water-Resources Investigations Report 03-4131 395p.
Sanford, W.E., Plummer, L.N., McAda, D.P., Bexfield, L.M., and Anderholm, S.K., 2004, Use of environmental tracers to estimate
parameters for a predevelopment-ground-water-flow model of the Middle Rio Grande Basin, New Mexico: U. S. Geological Survey Water-
Resources Investigations Report 03-4286, 102 p.
Plummer, L. Niel, Bexfield, Laura, M., Anderholm, Scott K., Sanford, Ward E., and Busenberg, Eurybiades, 2003, Hydrochemical tracers in
the Middle Rio Grande Basin, USA: 1. Conceptualization of groundwater flow. Hydrogeology Journal, v. 12, p. 359-388.
Sanford Ward E., Plummer L. Niel, McAda, Douglas P., Bexfield, Laura M., Anderholm, Scott K., 2004, Hydrochemical tracers in the Middle
Rio Grande Basin, USA: 2. Calibration of a groundwater model. Hydrogeology Journal, v. 12, p. 389-407.
Plummer, L.N., W.E. Sanford, L.M. Bexfield, S.K. Anderholm, and E. Busenberg, 2004, Using geochemical data and aquifer simulation to
characterize recharge and groundwater flow in the Middle Rio Grande Basin, New Mexico, in Groundwater Recharge in a Desert
Environment: The Southwestern United States, edited by J.F. Hogan, F.M. Phillips, and B.R. Scanlon, Water Science and Applications
Series, vol. 9, American Geophysical Union, Washington, D.C., 185-216.
Plummer, L. Niel, Bohlke, John Karl, and Doughten, Michael W., 2006, Perchlorate in Pleistocene and Holocene groundwater in North-
Central New Mexico. Environ. Sci. & Technol., v. 40, No. 6, 1757-1763.
http://water.usgs.gov/lab/chlorofluorocarbons/research/MRGB/