USING GEOCHEMICAL TRACERS TO DETERMINE AQUIFER CONNECTIVITY,
FLOW PATHS, AND BASE-FLOW SOURCES: MIDDLE VERDE RIVER
WATERSHED, CENTRAL ARIZONA
By
Caitlan McEwen Zlatos
__________________________
Copyright © Caitlan McEwen Zlatos 2008
A Thesis Submitted to the Faculty of the
DEPARTMENT OF HYDROLOGY AND WATER RESOURCES
In Partial Fulfillment of the Requirements
For the Degree of
MASTER OF SCIENCE
WITH A MAJOR IN HYDROLOGY
In the Graduate College
THE UNIVERSITY OF ARIZONA
2008
3
ACKNOWLEDGEMENTS
This thesis document would not exist were it not for the help and guidance I have
received from so many people over the past 2.5 years of my life. Special thanks go to my
two advisors, James Hogan and Tom Meixner, who kept me on task and provided me
with invaluable feedback along the way (feedback that extended beyond hydrology to
include bike safety tips: “Always wear your helmet” –Tom). Thanks go to Kyle Blasch,
Don Bills, and Don Pool of the USGS, for crucial feedback over the course of my study.
I am also indebted to the USGS crew who collected stream samples for me during their
June 2007 seepage run, and shared the corresponding discharge measurements and field
observations.
The success of my groundwater sampling campaign rests on the willingness of so many
private and public well owners to allow me well access. Though these people are too
numerous to list here, special thanks go to Jeanmarie Haney, Ken Black, Wendy
Ferguson, Jan Albright, Henry MacVittie, Frank Soto, Tony Gioia, and the staffs of Big
Park Water Company, Coconino and Prescott National Forests, Arizona State Parks, and
the National Park Service for taking the time to guide me to wells and springs, and set me
up with connections. For additional field help, I would like to thank Lissette de la Cruz,
Carolyn Keller, and Sam Treese. For indispensable lab help, I owe thanks to Tim Corley,
Chris Eastoe, James Hogan, Gretchen Oelsner, Stephen Osborn, Scott Simpson, and
Carlos Soto. For day-to-day support, advice, and great times, I owe thanks to all my
HWR colleagues and affiliated Tucsonans; they lightened the burdens of grad school, and
I am truly grateful for that. Special thanks go to Hargis + Associates, whose poster prizes
boosted not only my finances but also my confidence.
Finally, I would like to thank all the people whose encouragement over the years has
been critical to my success. I would have fallen apart somewhere along the way were it
not for the guidance of both my parents Laura & John Zlatos and my invaluable mentors
Amy & Ryan Mathur, all of whom continuously keep me steered toward my goals.
Thanks also go to my brother Jonny, the true source of my sanity. To all my friends and
family from MD and Juniata College: your love and support over the years has meant
everything to me. Lastly, much love and thanks go to Dane, my inspiration and source of
endless laughter.
This research was supported by the University of Arizona, Technology and Research
Initiative Fund (TRIF), Water Sustainability Program. Additional funding was provided
by SAHRA (Sustainability of semi-Arid Hydrology and Riparian Areas) under the STC
Program of the National Science Foundation, Agreement No. EAR-9876800.
4
TABLE OF CONTENTS
LIST OF FIGURES ............................................................................................................ 6
LIST OF TABLES.............................................................................................................. 7
ABSTRACT........................................................................................................................ 8
INTRODUCTION .............................................................................................................. 9
Scientific Motivation ....................................................................................................... 9
Societal Relevance ........................................................................................................ 10
Purpose and Objectives ................................................................................................ 13
STUDY AREA ................................................................................................................. 16
Background ................................................................................................................... 16
Physiography ................................................................................................................ 17
Hydroclimatology ......................................................................................................... 17
Surface-Water System ................................................................................................... 19
Surface-Water Use ........................................................................................................ 21
Groundwater Use.......................................................................................................... 28
Structural Features ....................................................................................................... 30
METHODS ....................................................................................................................... 32
Sample Collection ......................................................................................................... 32
Field Methods ............................................................................................................... 34
Laboratory Analyses ..................................................................................................... 35
Principle Components Analysis (PCA)......................................................................... 37
RESULTS ......................................................................................................................... 39
Organization of Results................................................................................................. 39
Stable Isotope Analysis: Groundwater ........................................................................ 39
Stable Isotope Analysis: Surface water........................................................................ 44
Solute Analysis: Groundwater ..................................................................................... 49
Solute Analysis: Surface water .................................................................................... 51
Radioactive Isotope Analysis: Groundwater ............................................................... 59
DISCUSSION................................................................................................................... 64
What is the nature of aquifer connectivity in the middle Verde River watershed?....... 64
The C, R-M, and Verde Formation aquifers ............................................................. 64
Minor aquifers .......................................................................................................... 67
What are the sources of base flow to the Verde River? ................................................ 68
Principal Components Analysis................................................................................ 68
Solute Ratio Mixing Diagrams.................................................................................. 73
Conceptual Model......................................................................................................... 83
Discussion of Incidental Recharge/Surface-Water Returns...................................... 86
Implications for Water Resources Management........................................................... 87
Study Limitations and Recommendations for Further Research .................................. 89
CONCLUSIONS .............................................................................................................. 91
APPENDIX A1: Surface-Water Geochemical Results ................................................... 93
APPENDIX A2: Groundwater Geochemical Results.................................................... 105
APPENDIX B: PCA Results for November 2006 Data ................................................ 111
5
TABLE OF CONTENTS – Continued
APPENDIX C: PCA Results for June 2007 Data.......................................................... 112
REFERENCES ............................................................................................................... 114
6
LIST OF FIGURES
FIGURE 1: Map of the study area……………………………………………………...11
FIGURE 2: Geologic map of the study area……………………………………………23
FIGURE 3: Geologic cross-section……………………………………………………..24
FIGURE 4: Groundwater pumping rates within the study area………………………...29
FIGURE 5: Discharge data over the period of study…………………………………...33
FIGURE 6: Stable isotopes in groundwater…………………………………………….41
FIGURE 7: Spatial patterns in δ18O in groundwater…………………………………....43
FIGURE 8: Stable isotopes in surface water…………………………………………....44
FIGURE 9: δ18O and discharge (June 2007) over distance, Verde River........................46
FIGURE 10: δ18O and discharge (June 2007) over distance, tributaries………………..47
FIGURE 11: Stable isotopic comparison of groundwater and surface water...................48
FIGURE 12: Ca/Sr versus SO4/Cl in groundwater……………………………………...51
FIGURE 13: Surface-water Br, Cl, and SO4 concentrations versus distance…………...53
FIGURE 14: SO4 versus Cl in surface water……………………………………………54
FIGURE 15: Surface-water Ca, Na, and Sr concentrations versus distance....................56
FIGURE 16: Ca/Sr versus SO4/Cl comparison of groundwater and surface water..........57
FIGURE 17: SO4/Cl and Ca/Sr versus distance...............................................................58
FIGURE 18: Map of tritium and radiocarbon activity in groundwater............................60
FIGURE 19: PCA for the Verde River………………………………………………….69
FIGURE 20: PCA conducted by reach for the Verde River………………………….....71
FIGURE 21: SO4/Cl versus Cl mixing diagrams, Oak Creek and Wet Beaver Creek….75
FIGURE 22: SO4/Cl versus Cl mixing diagrams, Verde River……………………...77-78
FIGURE 23: Conceptual model…………………………………………………………84
7
LIST OF TABLES
TABLE 1: Average annual streamflow, base flow, runoff, and AET…………………..20
TABLE 2: Aquifer characteristics……………..……......................................................25
TABLE 3: Stable isotopes in groundwater and surface water……………..……............40
TABLE 4: Anion concentrations in groundwater and surface water................................50
TABLE 5: Cation concentrations in groundwater and surface water...............................50
TABLE 6: Tritium concentrations in groundwater…………………………….………..61
TABLE 7: δ13C and Carbon-14 concentrations in groundwater…………………..…….62
8
ABSTRACT
Combining geochemical data with physical data produces a powerful method for
understanding sources and fluxes of waters to river systems. This study highlights this
for river systems in regions of complex hydrogeology, shown here through the
identification and quantification of base-flow sources to the Verde River and its
tributaries within the middle Verde River watershed. Specifically, geochemical tracers
(major solutes, stable and radioactive isotopes) characterize the principal aquifers (C,
Redwall-Muav, and Verde Formation) and provide a conceptual understanding of the
hydrologic connection between them. For the surface-water system, PCA is utilized to
identify potential base-flow sources to the Verde River on a several-kilometer scale.
Solute mixing diagrams then provide relative inputs of these sources, and when combined
with stream discharge, allow for quantification of water sources. The results of this study
provide an improved conceptual model that reveals the complexity of groundwatersurface water exchanges in this river basin.
9
INTRODUCTION
Scientific Motivation
Perennial river systems in arid and semiarid regions provide critical water
resources for human populations and habitats for riparian-dependant flora and fauna.
With pressure from both population growth and climate change, there is increasing
urgency and conflict related to sustaining the environmental flows necessary to support a
healthy riparian ecosystem (Sophocleous, 2007). Essential to the best management of
these resources is an understanding of the water sources that provide surface flow and
support phreatic vegetation (Sophocleous, 2002).
In the most basic sense groundwater discharge to a river sustains perennial base
flow in the absence of runoff; when groundwater is withdrawn from stream-adjacent
aquifers this flux can be reversed, bringing stream water into the aquifer (e.g. Theis,
1940; Sophocleous, 2002) and can ultimately dewater the riparian system and lead to the
elimination of riparian vegetation (Webb and Leake, 2006). More recently, research on
semiarid rivers has shown that seasonal floods can recharge the shallow riparian aquifer
(Baillie et al., 2007) and even regional aquifer systems (Plummer et al., 2004a&b; Eastoe
et al., 2008), providing a critical water source to sustain year-round flow. These
groundwater-surface water interactions constitute an important component of river
hydrology (Sophocleous, 2002).
Developing effective methods for identifying base-flow sources and quantifying
groundwater-surface water exchange at the river basin scale is imperative in order to best
understand and sustainably manage these water resources. In complex hydrogeologic
10
systems consisting of a variety of rock types and structural features, groundwater flow
paths and influx to perennial river systems can prove difficult to trace. The contact of
water with multiple stratigraphic units along its subsurface route forces chemical
evolution that reflects the varied mineralogic assemblages of those units (Freeze and
Cherry, 1979). By analyzing the geochemical composition of water using geochemical
tracers, mixing models and age-dating techniques (e.g., Hooper, 2003; Baillie et al.,
2007; Wahi et al., 2008), these flow paths and sources can be resolved. At the river basin
scale this can prove to be particularly effective for identifying the hydrogeologic controls
on groundwater-surface water exchange, which can have important implications for
groundwater resources, surface-water flows, and water quality (e.g., Plummer at el.,
2004b; Hogan et al., 2007; Oelsner et al., 2007; Eastoe et al., 2008)
Societal Relevance
The study of groundwater-surface water interactions is critical in the semiarid
Southwestern United States, where perennial stream flow is rare and essential for both
riverine environments and a burgeoning population. As one of Arizona’s few perennial
river systems, the middle Verde River watershed between Cottonwood and Camp Verde
(Figure 1) exemplifies these issues in a region of hydrogeologic complexity. Population
growth in the Southwest—one of the most rapidly increasing regional populations in the
country (Konieczki and Heilman, 2004)—is especially high in the middle Verde River
watershed. Yavapai County, which encompasses the majority of the watershed, was
11
Figure 1: Map of the study area, showing surface-water sampling sites, and USGS
streamflow gages are marked for reference.
12
declared the fastest-growing rural county in the United States in 1999 (Woods and Poole
Economics, Inc., 1999). The county’s population of 132,000 (as reported for the year
2000) is expected to more than double by 2050 (Woodhouse et al., 2002; Arizona Town
Hall Report, 2004). Sound water resources management is needed for this population
growth, given that groundwater constitutes the primary water resource used to support
development in the Verde Valley (Webb et al., 2007) and surface-water flows are crucial
for agriculture, recreation, and endangered species habitats.
Many disputes over surface-water rights in the Southwest currently focus on the
impact of groundwater pumping in stream-adjacent aquifer units on stream flow (Sax et
al., 2006; e.g., HRS Water Consultants, Inc., 2007; Briggs, 2007). In the upper Verde
River watershed, where population growth in Yavapai County has been the greatest,
plans to increase groundwater pumping from the Big Chino and Little Chino aquifers
may impact base flow to the headwaters of the river (Wirt and Hjalmarson, 2000; Wirt et
al., 2005; Rotstein, 2006). Quantifying the impact of such groundwater pumping on the
Verde River is difficult, however such efforts would be aided by an improved
characterization of groundwater-surface water interactions.
Current climate change predictions add to the urgency of characterizing basin
hydrogeology and groundwater-surface water interactions in the Southwest, as they
indicate a high likelihood of increasing aridity and water supply shortages (Seager et al.,
2007; Barnett et al., 2008). For over a decade Arizona has been in a state of drought
(Arizona Drought Preparedness Plan, 2004) that has been projected to continue for
another decade or more (Seager et al., 2007). In 2007 all of Arizona’s watersheds were
13
characterized as being in the midst of long-term “abnormally dry to severe drought
conditions” (Arizona Department of Water Resources, 2007). Predominantly rural
regions such as the Verde Valley are especially vulnerable to persistent drought due to
their reliance on locally-sourced water not augmented by Colorado River water (Arizona
Town Hall Report, 2004). In order to best manage the available water resources with
these increasing pressures, a greater understanding of groundwater flow paths and
groundwater-surface water interactions within the Verde River Valley must be achieved.
Purpose and Objectives
The purpose of the study is to use a combination of geochemical and physical data
to characterize the hydrogeologic conditions in the middle Verde River watershed.
Specifically, the main objectives of this investigation are:
(1) to understand the hydrologic flow paths and connections between the aquifers
underlying the Colorado Plateau and the adjacent Verde Formation aquifer in
the Verde Valley; and
(2) to identify and quantify how these potential groundwater sources contribute to
and sustain Verde River base flow.
The investigation relies on the distinct geochemical signatures of the base-flow
sources and the availability of discharge data for quantification of groundwater-surface
water fluxes. Comparisons will be made between the geochemical signatures of
groundwater and surface water, focusing on stable isotopic signatures (oxygen-18 and
deuterium), major solute concentrations, and relevant solute ratios (e.g., sulfate/chloride
14
and calcium/strontium). Additionally, groundwater flow paths will be examined using
radioactive isotopic values (3H and 14C).
It has been shown that a suite of geochemical tracers can be used effectively to
uniquely characterize arid basin hydrogeology (e.g., Plummer et al., 2004a; Mahlknecht
et al., 2006; Wahi et al., 2008). Isotopic compositions of oxygen and hydrogen are used
to reveal information related to elevation and seasonality of recharge (Clark and Fritz,
1997; Kendall and Coplen, 2001). For example these isotopes can be used to distinguish
the relative inputs of summer and winter precipitation to groundwater and surface water
(Plummer et al., 2004a; Baillie et al., 2007; Wahi et al., 2008). Conservative tracers such
as chloride and bromide and the ratio between them prove useful in distinguishing
groundwater sources, flow-path interactions, and mixing of waters (Davis et al., 1998;
Vengosh and Pankratov, 1998). Solute concentrations and ratios, when combined with
stable isotopic values, can distinguish the chemical signatures of groundwater sources
and potential mixing relationships among them and with surface water. Radioactive
isotopic analyses of tritium (half-life: 12.32 years) and carbon-14 (half-life: 5,730 years)
provide relative residence times for groundwater on both short and long timescales (Clark
and Fritz, 1997; Zhu, 2000). Groundwater that is produced via mixture between young
and old water sources can be identified through these analyses.
Groundwater-surface water interactions can be further described by performing
principle components analysis (PCA) on a suite of geochemical data. PCA provides the
means to determine the relationships between the forces driving variance in groundwater
geochemical compositions and those driving variance in surface water compositions
15
(Christopherson and Hooper, 1992; Liu et al., 2004). As such PCA is capable of
discerning potential end members (base-flow sources) that are capable of explaining the
observed geochemical composition of surface-water samples.
16
STUDY AREA
Background
The Verde River and its tributaries are valued for their scenery, fish and wildlife,
as well as their cultural and historical significance. The Verde River represents Arizona’s
only designated Wild and Scenic River (National Wild & Scenic Rivers System, 2008),
and has been cited as one of the ten most endangered rivers in the U.S. due to current and
continuing stresses of population growth (American Rivers, 2006). Endangered species
such as the desert nesting bald eagle and the razorback sucker rely on the river’s flow;
bald eagle nesting areas are the cause for annual closures or restrictions of several reaches
along the Verde River from December 1 to June 15 (Arizona Game and Fish Department,
2007). Additionally, recreational sites such as Slide Rock Park on Oak Creek and
wilderness areas such as those found along Sycamore, Wet Beaver, and West Clear
Creeks attract tourists and outdoor enthusiasts to the region.
The watershed's water resources sustain population centers in and around the
towns of Clarkdale, Cornville, Cottonwood, Jerome, Page Springs, Rimrock, Sedona, and
Camp Verde, as well as irrigated agricultural activities throughout the valley. Stream
flow also supports downstream water users including the Salt River Pima-Maricopa and
Fort McDowell Indian Communities, the Salt River Project, and the City of Phoenix
(Sonoran Institute, 2007). Ultimately, 90 to 95% of Verde River surface water is claimed
by downstream water rights holders (Sonoran Institute, 2007).
17
Physiography
The middle Verde River watershed, which encompasses approximately 6,500 km2
of central Arizona, stretches along the Verde River from Paulden (USGS gage 09503700)
south to its exit from the watershed below Camp Verde (09506000) (Figure 1). The
watershed is located within the Transition Zone—the northwest-southeast structural
province where the Basin and Range province meets the Colorado Plateau province—and
is thus heavily faulted and contains both extensional and compressional features.
Elevations of the basin floor range from 910 to 1100 m above sea level. The 2,000 to
2,300 m high Mogollon Rim, which separates the Transition Zone from the Colorado
Plateau, forms the watershed’s boundary to the north and northeast. The Black Hills
bound the watershed to the west and southwest at elevations of approximately 2,000 to
2,400 m (southwest to northwest).
Hydroclimatology
The climate of the middle Verde River watershed is arid to semiarid with a
bimodal precipitation regime. The summer monsoon season, occurring from July to
September, results from moist air brought in from the Gulf of Mexico and Gulf of
California. The second precipitation season occurs during the winter months (December
to March), bringing moisture from the Pacific Ocean. Winter precipitation provides a
larger contribution to surface-water flow and groundwater recharge in the watershed,
primarily due to the sustained duration of winter storms (compared to the short duration,
18
high-intensity nature of summer storms) and lower evapotranspiration rates as a result of
lower winter temperatures and solar radiation (Blasch et al., 2006).
The combination of winter and summer precipitation for the upper and middle
Verde River watersheds amounts to approximately 75% of the average annual
precipitation, with winter precipitation accounting for approximately 44%, and the
summer monsoon accounting for approximately 31% (Blasch et al., 2006). Average
precipitation ranges from approximately 250 mm/yr in the valley to 1000 mm/yr in the
mountains and higher altitudes of the Coconino Plateau (Western Regional Climate
Center, 2008). Average annual rainfall is approximately 460 mm/yr, or 3.52 km3/yr over
the entire watershed. Of this amount 0.57 km3/yr falls as snow, with local averages of 50
mm/yr at Tuzigoot National Monument (elevation: 1060 m), 230 mm/yr in Jerome
(elevation: 1570 m), and 2340 mm/yr on Mingus Mountain (elevation: 2320 m) (Blasch
et al., 2006).
Stable isotopic compositions of precipitation in the region are inversely related to
elevation. Winter precipitation at the Grand Canyon (elevation: 2152m) has the lowest
δ18O and δ2H values, averaging -14.1‰ for δ18O and -98.0‰ for δ2H (Bills et al., 2007).
Flagstaff, at a slightly lower elevation of 2137m, has a more enriched average winter
precipitation (-10.9‰ δ18O, -79.7‰ δ2H), and Verde Valley (elevation: 914m) winter
precipitation has the highest isotopic values, with -8.3‰ δ18O and -56.0‰ δ2H (Blasch et
al., 2006). A local meteoric water line for Flagstaff has been defined based on IAEA
Flagstaff isotopic data; this Flagstaff Meteoric Water Line (FMWL) follows the equation
δ2H = 6 δ18O – 14 ‰ (Blasch et al., 2006).
19
Long-term geochemical data for solute concentrations in precipitation exists
through the National Atmospheric Deposition Program (NADP) and its Grand Canyon
monitoring station. These data are assumed to be representative of the chemical
composition of precipitation in the middle Verde Valley because the Grand Canyon
experiences the same bimodal precipitation regime. With this assumption, these data are
used in this study for the chemical signature of precipitation in analyses of potential flow
sources.
Surface-Water System
This study focuses on a 85 km-long stretch of the Verde River from its confluence
with Sycamore Creek to the USGS gage near Camp Verde (09506000) (see Figure 1).
Major perennial tributaries along this stretch of the river—Sycamore Creek, Oak Creek,
Wet Beaver Creek, and West Clear Creek—transport water from the Coconino Plateau
via northeast-southwest trending canyons cutting through the Mogollon Rim. These
tributaries enter the Verde River at approximately 85 km, 44 km, 24 km, and 13 km
upstream from USGS gage 09506000, respectively. From the other side of the basin,
surface-water contributions from the Black Hills and northwest region are ephemeral
(Owen-Joyce and Bell, 1983).
USGS gages are present at several points in the study area, two of which are
located on the Verde River: Verde River near Clarkdale (09504000) and Verde River
near Camp Verde (09506000). Tributary gages exist at Oak Creek near Sedona
(09504420), Oak Creek near Cornville (09504500), Wet Beaver Creek near Rimrock
(09505200), Beaver Creek near Lake Montezuma (09505400), and West Clear Creek
20
near Camp Verde (09505800). Average annual stream flow and base flow increase with
distance downstream for both the Verde River and its tributaries (Table 1). Base flow
comprises a greater component of annual stream flow for the Verde River than for its
tributaries, which receive more direct runoff from the ~1000 mm of annual precipitation
on the Colorado Plateau. The current trend in Verde River base flow is one of decline: at
the Verde River near Clarkdale USGS gage (09504000) and at the Verde River near
Camp Verde gage (09506000), base flow decreased approximately 1x106 m3/yr and
2x106 m3/yr respectively during the period 1994-2006 (Blasch et al., 2006).
Table 1: Average annual streamflow, base flow and runoff components, and actual
evapotranspiration (AET) for USGS gages within the study area (data from Blasch et al.,
2006; NC = not calculated, AET rates were calculated for riparian corridors along the
Verde River and its tributaries over the period 1961—2003 by base-flow reduction or
average consumptive-use values).
USGS
Drainage Avg. annual Base flow
Runoff
streamflowArea
streamflow component component
AET
gaging station
(km2)
(m3/s)
(m3/s)
(m3/s)
(m3/yr)
Verde River near
Clarkdale
(09504000)
Verde River near
Camp Verde
(09506000)
Oak Creek near
Sedona
(09504420)
Oak Creek near
Cornville
(09504500)
Wet Beaver
Creek (09505200)
West Clear Creek
(09505800)
9,073
4.8
2.2
2.5
3.7 x 106
12,973
11.6
NC
NC
8.0 x 106
603
2.3
0.9
1.4
NC
919
2.4
NC
NC
3.5 x 106
287
0.9
0.2
0.7
5.9 x 105
624
1.8
0.5
1.3
1.3 x 106
21
Surface-Water Use
Within the study area, ditch diversions along the Verde River add to the
complexity of surface-water monitoring. These diversions are mainly used for
agricultural purposes; this practice is the largest use of surface water in the middle Verde
River watershed (Sonoran Institute, 2007). At least seven major ditches divert water
from the Verde River in the study area: Tavasci, Hickey, Cottonwood, OK, Eureka,
Woods (Verde), and Beasley Flat ditches. The estimated rate of evapotranspiration for
crop irrigation is 50% of the water applied (ADWR, 2000; Blasch et al., 2006). Return
flows from the ditches occur and like the diversions are largely unmonitored.
Diverted surface water is used to irrigate ~10.5 km2 (2,600 acres) of land in the
areas surrounding Cottonwood, Cornville, and Camp Verde. This irrigated land is
comprised of roughly 95% alfalfa and grass, and 5% corn, grapes, sorghum, and pecans.
Based on consumptive-use calculations for these crops using a modified Blaney-Criddle
method for the Jerome weather stations, the water needed for these agricultural lands is
1.09x107 m3 per 8- to 9-month growing season (8,850 acre-feet; S. Tadayon, USGS,
personal commun., 2008). Calculated over an 8-month growing season, this translates to
0.521 m3/s (18.4 cfs). When the efficiency of the irrigation systems is taken into account,
the actual amount of water diverted is likely to be higher than this consumptive use rate.
Assuming an efficiency of 50%, the amount of water diverted for irrigation would be
36.8 cfs.
22
Groundwater Hydrogeology
As noted, the middle Verde River watershed is hydrogeologically complex due to
its location within the Transition Zone between the Colorado Plateau and the Basin and
Range structural provinces (Figure 2). Three main aquifers provide groundwater storage
in the study area: the Paleozoic Redwall-Muav and Coconino aquifers, and the Tertiary
Verde Formation aquifer (Figure 3). Minor aquifers also occur in Tertiary basalt units
and Holocene alluvium (Owen-Joyce and Bell, 1983). Previous studies treated the
aquifers as a single regional aquifer and assumed general hydraulic connection based on
well and test hole hydraulic head data (e.g. Levings, 1980; Owen-Joyce and Bell, 1983).
Hydrogeologic studies of the Coconino Plateau (the local physiographic portion of the
Colorado Plateau) have done much to characterize the Coconino and Redwall-Muav
aquifers (e.g. Monroe et al., 2005; Bills et al., 2007).
Geochemical analyses can resolve groundwater sources within the watershed due
to characteristic differences in aquifer composition (Table 2). The Redwall-Muav (R-M)
aquifer, consisting of units formed mainly in a shallow marine depositional environment,
is composed of carbonates (calcite and dolomite), with lesser amounts of silicates and
feldspar. In contrast, the overlying aquifer—the Coconino or “C” aquifer—represents a
transitional phase from shallow marine to a coastal plain environment and is a mixture of
silicates, calcite, dolomite, and minor potassium feldspar and evaporites. The Verde
Formation aquifer differs from both in that it is lacustrine in origin. Like the R-M
aquifer, carbonates are a major mineralogic component of the Verde Formation aquifer,
23
Figure 2: Geologic map of the study area showing the major and minor aquifer units, and
groundwater sampling sites. Major faults are labeled (after Langenheim et al., 2005): the
Verde Fault zone (VF), Sheepshead Fault (SH), Page Springs Fault (PS), Bear Wallow
Canyon Fault (BWCF), Cathedral Rock Fault (CRF), and Oak Canyon Fault (OCF). Of
note is the marked hypothetical division of the VFS subaquifer from the VFN subaquifer
(see Results for explanation).
GROUNDWATER FLOW PATH (approximate)
WELL
FAULT—arrows indicate direction
of movement
VG10060706
VG02240805
VG11170603
Modified from Woodhouse et al. (2002)
Figure 3: Cross-section showing the principal aquifers, regional groundwater flow paths, and wells along this transect.
Approximate trace of cross-section shown on geologic map.
VG11170602
VG03120801
PRE-CAMBRIAN BASEMENT
R-M
C
TERTIARY BASALT
VG03110803
VG10070703
VERDE FORMATION
24
Redwall
Redwall Limestone
-Muav
Martin
Formation
Supai
Group
76 – 85
110 – 150
Devonian
55 – 190
200 – 270
190 – 240
490 – 1220
Thickness
(m)
Mississippian
Pennsylvanian/
Permian
Schnebly Pennsylvanian/
Hill
Permian
Formation
Permian
Coconino
Sandstone
C
Tertiary
Verde
Formation
Verde
Geologic
Age
Geologic
Unit(s)
Aquifer
Dolostone,
Siliciclastic interbeds
(minor)
Limestone
Chert
(similar to Schnebly
Hill Formation)
Sandstone
Siltstone
Mudstone
Limestone
Evaporites (minor)
Quartz arenite
Dolomite, Quartz
Calcite, Dolomite, Quartz
Quartz, Calcite, Dolomite, Illite, K-spar
Quartz, Calcite, Dolomite [CaMg(CO3)2],
Illite, K-spar, Gypsum, Halite
Quartz, K-spar [K(AlSi3O8)]
T = 27 – 1,885 (gal/d)/ft
Calcite [CaCO3], Gypsum [CaSO4·2H2O],
Halite [NaCl], Montmorillonite
[(Na,Ca)0.33(Al,Mg)2Si4O10(OH)2·nH2O],
Illite [K0.8Al2(Al0.8Si3.2)(OH)2],
Quartz [SiO2]
Limestone
Mudstone
Evaporite deposits
Sandstone
Mostly confined; solution
fractures dominant in Redwall
(source: data compiled in Bills et al.,
2005)
T = 20 – 16,000 (gal/d)/ft
Mostly unconfined; fractured
locally
(source: data compiled in Bills et al.,
2005)
T = 83.8 – 181,400 (gal/d)/ft
Mostly unconfined; fractured
locally
(source: data compiled in Blasch et
al., 2006)
Aquifer
Characteristics
Mineralogy
Rock
Types
Table 2: Geologic characteristics of the three primary aquifers in the Middle Verde River watershed (T =
Transmissivity). Data gathered from Beus (2003), Bills et al. (2007), Blakey (1990a&b), Blasch et al. (2006), McKee
and Gutshick (1969), Middleton et al. (2003), Monroe et al. (2005), and Owen-Joyce and Bell (1983).
25
26
but the Verde Formation contains a greater abundance of mudstone, clays, and evaporite
deposits such as gypsum and halite.
The two main units of the R-M aquifer within the study area are the dolomitic
Martin Formation (known as the Temple Butte Formation in the Grand Canyon
sequence), and the karstic Redwall Limestone. The Martin Formation sources springs
and wells 61 to 370 m deep located mainly in the Black Hills, and near the Sedona and
Red Rock area. Depth to water in these wells ranges from 44 to 280 m below land
surface (Owen-Joyce and Bell, 1983). The Redwall Limestone, a nearly pure limestone
with local dolomitization and chert lenses (McKee and Gutshick, 1969), contains
significant solution fractures and channels. It supplies wells 69 to 251 m deep west of the
Clarkdale-Cottonwood area and in parts of the Sedona region, as well as springs along
the southern part of Sycamore Creek. Depth to water in wells ranges from artesian
conditions to 223 m below land surface (Owen-Joyce and Bell, 1983).
Within the study area, the main units of the C-aquifer system are the Supai Group,
Schnebly Hill Formation, and Coconino Sandstone. The Supai Group and overlying
Schnebly Hill Formation are composed of sandstone, siltstone, mudstone, limestone, and
dolomite, with minor evaporites present in the Schnebly Hill Formation (Blakey, 1990a).
Sandstone units contain calcite and dolomite crystals from diagenesis; in general, Supai
Group units are cemented with calcite (Blakey, 1990b). The lower and middle units of
the Supai Group are typically saturated within the study area, and the lower unit in some
places becomes a confining layer for the R-M aquifer (Blasch et al., 2006). Outcrops of
the C-aquifer units within the study area occur along the upper Verde River as well as
27
along the Mogollon Rim near Sedona. Much of the groundwater pumped in the region of
Page Springs, Oak Creek, Big Park, Sedona, and north of Rimrock originates from wells
drilled 27 to 976 m into the Supai Formation. Depth to water in wells ranges from
artesian conditions to 227 m below land surface (Owen-Joyce and Bell, 1983). Upstream
from Page Springs, the Supai Group supplies a portion of the perennial flow of Oak
Creek (Levings, 1980).
The Coconino Sandstone is the upper unit of the C aquifer, and is composed
mainly of silica-cemented quartz arenite with minor amounts of potassium feldspar
(Middleton et al., 2003). Outcrops are present along the Mogollon Rim, Oak Creek
Canyon, Wet Beaver and West Clear Creeks; these tributaries receive base flow from the
Coconino (Owen-Joyce and Bell, 1983), but very few wells tap this unit below the
Mogollon Rim. Wells located mainly northeast of and atop the Mogollon Rim obtain
water from the Coconino Sandstone at depths to water from 84 to 241 m below land
surface (Owen-Joyce and Bell, 1983).
The Verde Formation, formed in a closed-basin Tertiary lake, consists of
limestone and mudstone with interbedded basalt flows, and covers approximately 840
km2 of the Verde Valley (Owen-Joyce and Bell, 1983). Six facies are recognized, four of
which are limestone, the other two consisting of sandstone and mudstone (Twenter and
Metzger, 1963). Limestone facies are the most permeable and are frequently confined by
overlying mudstone units. Notably, the mudstone facies contain evaporite deposits,
namely gypsum and halite (Owen-Joyce and Bell, 1983), and clays, namely
montmorillonite and illite (Waddell, 1972). In general evaporites are more common near
28
the center of the basin, whereas clastic deposits dominate toward the margins (Bressler
and Butler, 1977). Wells drilled 9 to 495 m deep obtain water from the Verde Formation
primarily in the valley surrounding the Verde River, from north of Clarkdale to Camp
Verde. Depth to water is flowing at the land surface near Cornville and Rimrock and up
to 149 m below land surface south of Cottonwood (Owen-Joyce and Bell, 1983).
Groundwater Use
Groundwater uses in the watershed include domestic, industrial, agricultural, and
golf course irrigation. Groundwater pumping ranges from small-scale domestic wells
(most classified as “exempt”—those whose maximum pumping capacity is ≤ 35 gpm, or
191 m3/day) to large-scale water users (currently pumping up to 1500 m3/day; Figure 4).
Domestic wells are densely populated along the Verde River, Oak Creek, Wet Beaver
Creek, and West Clear Creek (especially in and around the towns of Clarkdale,
Cottonwood, Cornville, and Camp Verde). Large-scale water users (including municipal
and private water companies, golf courses and industrial users) are located mainly near
population centers including the aforementioned towns as well as the towns of Sedona
and the Village of Oak Creek.
Total groundwater usage within the watershed is approximately 2.10x107 m3/yr
(17,020 acre-feet/yr). This calculation is based on a combination of the 2005 data for
non-exempt wells (large-scale water users) utilized in the Northern Arizona Regional
Groundwater Flow Model (L. Graser, ADWR, personal commun., 2008) and the average
29
Figure 4: Spatial distribution of groundwater pumping in the middle Verde River
watershed (based on 2005 data from L. Graser, ADWR, personal commun., 2008).
Shown are both non-exempt wells—rates in cubic meters per day (cmd)—and exempt
wells (the latter having a maximum pumping capacity of 35 gpm).
30
annual domestic water use for the Verde Valley subbasin over the period 1990—2003
(1,900 acre-feet/yr: Blasch et al., 2006).
Structural Features
As stated previously, the study area reflects both features of the Colorado Plateau
and the Basin and Range. In general the Paleozoic strata within the Verde Valley are
almost continuous from the Transition Zone into the Colorado Plateau, with a regional
dip of less than 10° to the northeast (Twenter and Metzger, 1963). Normal faults
characteristic of the extensional Basin and Range province strike north to northwest
through several areas of the middle Verde River watershed (Anderson and Creasey,
1958). Notable features include the Verde Fault zone and Oak Creek Fault system (see
Figure 2).
The Verde Fault zone, which includes the Verde Fault and Airport Fault, exists
along the western margin of the Verde Valley. This fault zone drops rock units
downward toward the east with displacements of up to 1100 m. The fault system
obstructs groundwater flow from the Black Hills east toward the Verde River, directing
flow to the southeast (Twenter and Metzger, 1963). The Oak Creek Fault system
includes Oak Creek Fault and Page Springs Fault. The 180 to 210 m of displacement
along the north-south striking Oak Creek Fault brings the permeable Redwall Limestone
and lower and middle units of the Supai Group into contact with the upper impermeable
unit of the Supai Group, forcing water upward along the fault as groundwater influx to
Oak Creek (Levings, 1980). The Page Springs Fault brings the Paleozoic aquifers to the
31
surface, which is considered responsible for the relatively large influx of water to Oak
Creek at Page Springs (Langenheim et al., 2005). Historically, Page Springs discharges
between 1.0 to 1.2 m3/s (36 to 42 cfs: Twenter and Metzger, 1963; Levings, 1980).
32
METHODS
Sample Collection
Surface-water and groundwater samples were collected for stable isotope, solute,
and radioactive isotope analyses. Sample collection was focused on the region of the
middle Verde River watershed spanning from the headwaters of Oak Creek south to
USGS gage 09506000 below Camp Verde, and from the Black Hills east to Rimrock (see
Figure 1). Surface-water samples were obtained from publicly accessible points along
the Verde River and its major tributaries Sycamore Creek, Oak Creek, Wet Beaver Creek,
and West Clear Creek. Sampling locations are discussed in terms of kilometers upstream
from the USGS gage 09506000 (Verde River near Camp Verde). A total of 126 surfacewater samples were collected, split among 3 main seasonal sampling campaigns:
November 2006, June 2007, and February/March 2008. November 2006 samples (n=34)
are considered representative of winter base-flow conditions, when discharge at gage
09506000 was approximately 4.67 m3/s (165 cfs; Figure 5). June 2007 samples (n=74),
collected by the USGS concurrently with discharge data, are indicative of summer premonsoon base flow (gage 09506000 discharge: 0.88 m3/s, or 31 cfs). February/March
2008 samples (n=18) were collected during the spring snowmelt period, when discharge
values at gage 09506000 were 47.9 to 54.1 m3/s (1,690 to 1,910 cfs; USGS, 2008).
Groundwater sample collection was focused on public, state, and private wells
and springs within the study area. A total of 67 groundwater samples were collected over
the course of the study, 6 of which were from springs. The three main aquifers were
targeted (n=59), though samples from the minor aquifer units were collected as well
(n=8).
33
Verde River at Clarkdale (09504000)
Verde River near Camp Verde (09506000)
100000
10000
1000
1000
100
100
10
10
1
Oak Creek at Cornville (09504500)
3/1/08
1/1/08
11/1/07
9/1/07
7/1/07
5/1/07
3/1/07
10000
1/1/07
3/1/08
1/1/08
11/1/07
9/1/07
7/1/07
5/1/07
3/1/07
1/1/07
11/1/06
10000
1
Oak Creek near Sedona (09504420)
11/1/06
Discharge (cfs)
10000
Day of Year
9/1/07
11/1/07
1/1/08
3/1/08
9/1/07
11/1/07
1/1/08
3/1/08
5/1/07
5/1/07
7/1/07
3/1/07
3/1/07
7/1/07
1/1/07
Day of Year
1/1/07
Wet Beaver Creek at Rimrock (09505200)
11/1/06
3/1/08
1/1/08
11/1/07
10000
9/1/07
1
7/1/07
1
5/1/07
10
3/1/07
10
1/1/07
100
11/1/06
Discharge (cfs)
100
11/1/06
1000
1000
Wet Beaver Creek at Lake Montezuma (09505400)
10000
1000
Discharge (cfs)
1000
100
10
100
1
10
0.1
0.01
3/1/08
1/1/08
11/1/07
9/1/07
7/1/07
5/1/07
3/1/07
1/1/07
11/1/06
1
West Clear Creek near Camp Verde (09505800)
10000
Day of Year
Day of Year
Discharge (cfs)
1000
100
10
3/1/08
1/1/08
11/1/07
9/1/07
7/1/07
5/1/07
3/1/07
1/1/07
11/1/06
1
Day of Year
Figure 5: Discharge data for the Verde River and its tributaries at USGS gages within the
study area over the study duration (data from USGS, 2008). The three sampling time
periods (November 2006, June 2007, and February/March 2008) are marked. Note that
discharge scales differ.
34
Field Methods
Temperature, pH, and specific conductance were measured for each surface-water
and groundwater sample using a field calibrated YSI-556 Multi Probe System (MPS).
Sample site coordinates and altitudes were determined using a Differential Global
Positioning System.
Both filtered and unfiltered samples were collected at each site for solute and
isotopic analyses, respectively. A 125 mL sample was filtered in the field to be used for
alkalinity and solute analyses. Filtration involved a syringe coupled with either a) a
25mm Whatman polypropylene 0.45μm disposable syringe filter (USGS sample
collection in June 2007) or b) a 47mm Whatman Binder-Free Glass Microfiber 0.45µm
filter in a filter housing apparatus (all other surface-water and groundwater sample
collection). The syringe was triple-rinsed with sample water, then the filter attached and
filtration conducted. A new filter was used at each site; if filters became clogged more
than one filter was used. In order to avoid contamination of filtered samples, only HDPE
bottles certified to meet or exceed EPA specifications were used. Samples were stored in
coolers, where they were kept on ice continuously until refrigeration became available.
Unfiltered samples were collected in HDPE bottles triple-rinsed with sample
water. A 60 mL sample was collected for stable isotope analysis, for both surface-water
and groundwater samples. For groundwater sampling sites, additional quantities of 500
mL and 1000 mL were collected for tritium and carbon-14 analysis, respectively. Glass
bottles were used; clear glass for tritium and amber glass for carbon-14. Care was taken
35
to avoid creating headspace in sample bottles; in the case of carbon-14 sample bottles,
Parafilm was used to create an airtight seal.
All surface-water samples were collected from the thalweg of the stream.
Groundwater samples were collected from the well head or from the nearest access point
when the well head was inaccessible. When a well was not under continuous pumping
conditions before sampling and circumstances allowed for it, three well volumes were
pumped to purge the well. Pumped groundwater was contained in a triple rinsed plastic
bucket while field parameters were measured, and then transferred to sample bottles
either directly or by syringe filtration.
Laboratory Analyses
Alkalinity, solute concentration, and isotopic analyses were performed in various
laboratories at the University of Arizona. Alkalinity and solute concentration analyses
were conducted in the Department of Hydrology and Water Resources, using the filtered
samples, which were kept refrigerated in the lab between analyses. Alkalinity titrations
were performed within 24 hours of sampling using an automated Mettler Toledo DL53
Titrator operated with the LabX Light Titration Version 2.0 program to deliver 0.1 M
HCl incrementally for equivalence point titration. Calibration of the HCl solution was
performed using Na2CO3 solutions of known concentrations, and the pH probe was
calibrated using standard pH buffers. Alkalinity is reported in mg/L acid neutralizing
capacity (ANC) as CaCO3.
36
Six major anion (F, Cl, NO2, Br, NO3, and SO4) concentrations were analyzed
using a Dionex Ion Chromatograph (IC) operated in the Department of Hydrology and
Water Resources. The IC achieves analyte separation using an AS17 analytical column
by eluting with a KOH gradient (via EG50 eluent generator and GS50 gradient pump).
Anion concentrations were measured by a CD25 conductivity detector after KOH
removal by ASRS suppressor column. Internal standard checks were inserted into the
sample sequence after every tenth sample for quality control. The detection limit for all
anions is approximately 0.025 ppm. Analytical precision is 5% or better for
concentrations exceeding 1 ppm and 10% or better for concentrations lower than 1 ppm.
Nine major base cations and trace elements (As, B, Ba, Ca, K, Mg, Na, Si, Sr)
were analyzed using a Perkin-Elmer Optima 5100DV Inductively Coupled Plasma
Optical Emission Spectrometer (ICP-OES). Through this method, the specific
wavelengths of a cation’s emission spectra were separated using an echelle
polychromator and the intensities were measured using a segmented-array chargecoupled device (SCD). Detectable wavelengths range between 163 and 403 nm.
Stable isotope analyses yielding δ2H, δ18O, and δ13C values were conducted in the
Environmental Isotope Laboratory of the Department of Geosciences, using a Finnigan
Delta S gas-source Isotope Ratio Mass Spectrometer (IRMS). δ2H analysis was
completed via reduction by Cr metal at 750 °C (Gehre et al., 1996); δ18O values were
determined via CO2 equilibration at 15 °C (Craig, 1957). δ13C was measured on CO2
samples created during the process of converting dissolved inorganic carbon (DIC) to
CO2 via acid hydrolysis during 14C sample preparation. Isotopic values are reported in
37
per mil (‰) notation relative to VSMOW (for δ2H and δ18O) and VPDB (δ13C). Results
are precise within ± 0.9‰ for δ2H, ± 0.08‰ for δ18O, and ± 0.1‰ for δ13C.
Samples were analyzed for tritium concentrations using a Quantulus 1220
spectrophotometer housed in an underground laboratory in the Department of
Geosciences. Electrolytic enrichment and liquid scintillation decay counting were used,
consistent with the methods outlined by Theodórsson (1996). Results are reported in
tritium units (TU) relative to the NIST SRM 4361 B and C standards. The detection limit
was 0.6 TU and precision was 0.18 to 0.37 TU.
Carbon-14 analyses were performed at the NSF – Arizona Accelerator Mass
Spectrometer (AMS) Laboratory, and are reported in terms of percent modern carbon
(pMC) relative to the NIST oxalic acid I and II standards. Analysis was performed on
graphite after CO2 samples were reduced to this state. Analytical precision is 0.1 to 0.9
pMC, with a detection limit of 0.2 pMC.
Principle Components Analysis (PCA)
PCA for the winter base-flow and summer surface-water data was performed in
order to reveal geochemical affinities of different groundwaters and to determine
potential base-flow sources. This analysis was performed following the steps outlined in
Christophersen and Hooper (1992). First bivariate plots were constructed for each pair of
geochemical tracers in an attempt to determine which were conservative (in other words,
their concentrations are minimally affected by chemical reactions). Conservative
behavior was judged based on whether tracers exhibited approximately linear
38
relationships with other tracers, and on the ability of surface-water data to be bound by
potential end members in the bivariate tracer plots (after Liu et al., 2004). Nine tracers
were considered to be conservative and used as input for PCA: conductivity, Ca, Mg,
Na, Sr, alkalinity (ANC as CaCO3), Cl, Br, and SO4. Because of the expected
fractionation impact of evaporation on the behavior of δ18O and δ2H in an arid
environment, these two tracers were excluded as constraints for PCA of June 2007 data.
In order to standardize the data for analysis, both the river’s and the potential end
members’ geochemical data were normalized to the river’s median geochemistry by
subtracting the median concentrations and dividing by the standard deviations. For the
individual reach analysis, this standardization was done specific to each reach’s median
chemical concentrations. After normalization, PCA was conducted on the surface water
data using the princomp command in MATLAB. The eigenvalues returned in the latent
matrix were examined to determine whether a significant percentage of variance could be
explained by the first two principal components, with the goal of 80 - 90%. Matrix
multiplication between the normalized stream data and the coefficient matrix was then
performed, resulting in the eigenvectors used to create U-space projections of the data.
Potential end members (base-flow sources) were likewise projected into U-space using
the surface-water coefficient matrix.
39
RESULTS
Organization of Results
Results of this study are organized based on the three analytical approaches:
stable isotope analysis, solute analysis, and radioactive isotope analysis. All groundwater
and surface-water samples were analyzed for 18O and 2H as well as anion and cation
concentrations, with a specific focus on SO4/Cl and Ca/Sr ratios. These ratios were
utilized in order to best characterize groundwater geochemistry and groundwater-surface
water interactions: the divalent cation ratio Ca/Sr furnishes information regarding solute
source (e.g., silicate weathering versus carbonate weathering), and the mixed-valence
ratio SO4/Cl provides information pertaining to the presence of and type of evaporites
(e.g., gypsum versus halite). Radioactive isotope results are limited to a select set of
groundwater samples that were chosen for 3H (n=12) and/or 14C analysis (n=10) based on
aquifer source, potential flow paths, and overall location. A comprehensive summary of
the geochemical data from this study is available in Appendix A.
Stable Isotope Analysis: Groundwater
Groundwater δ18O and δ2H values range from -12.0 to -8.5 ‰ and -86.7 to -67.2
‰, respectively (Table 3). This range is generally clustered about the Flagstaff winter
precipitation average, though the lower and upper ends of this range extend toward the
Grand Canyon and Verde Valley winter precipitation signatures, respectively (Figure 6).
Within this range, individual aquifer units occupy narrower ranges that can be used to
distinguish the various groundwater sources. Groundwater sourced from the C aquifer is
40
Table 3: Ranges, medians, and standard deviations of groundwater and surface water
stable isotopic values in the middle Verde River watershed (* additional data from Blasch
et al., 2006; Rice, 2007).
Minimum
Maximum
Median
Std. dev.
(‰)
(‰)
(‰)
(‰)
18
2
18
2
18
2
18
n δ O δH δ O
δH
δ O δ H δ O δ2H
Groundwater
Colorado Plateau
C 19 -11.9 -86.7 -8.5
-67.2 -11.7 -81.0 1.0
4.7
R-M 4 -11.9 -83.0 -11.5 -80.6 -11.6 -81.8 0.18 0.98
Valley
Alluvium 5
Verde Fm 35
VFN 24
VFS 10
-10.9
-12.0
-12.0
-10.7
-78.1
-83.4
-83.4
-78.5
-10.0
-10.1
-10.1
-10.1
-73.9
-74.3
-74.3
-75.1
-10.4
-11.0
-11.3
-10.5
-76.8
-78.3
-79.8
-76.4
0.33
0.57
0.51
0.21
1.8
2.5
2.4
1.1
5
-10.8
-75.7
-9.2
-69.3
-9.9
-72.1
0.61
2.7
Surface water
Verde River
Nov-06 11
Jun-07 49
Feb/Mar-08 13
-10.9
-11.1
-11.2
-78.5
-77.9
-79.7
-10.4
-9.4
-10.7
-75.0
-73.2
-75.2
-10.7
-10.2
-11.1
-76.8
-76.0
-78.2
0.15
0.41
0.15
1.1
1.5
1.5
Oak Creek
Nov-06 13
Jun-07 8
Feb/Mar-08 4
-11.8
-11.7
-11.5
-83.0
-84.3
-80.5
-11.5
-10.9
-11.4
-79.4
-78.2
-79.4
-11.7
-11.4
-11.4
-82.0
-82.9
-80.0
0.11
0.29
0.05
1.1
1.9
0.56
Wet Beaver
Creek
Nov-06
Jun-07
Feb/Mar-08
-11.2
-10.9
n/a
-79.3
-81.0
n/a
-10.4
-10.7
n/a
-76.4
-79.3
n/a
-11.0
-10.7
n/a
-78.8
-89.6
n/a
0.29
0.15
n/a
1.1
0.9
n/a
Southwest
Black Hills*
7
3
1
41
-55
Verde Valley
winter
precipitation
Groundwater median
-60
Alluvium
Black Hills
-65
Global Meteoric Water Line
δ2H = 8.13*δ18O + 10.8 ‰
Verde Formation
VFN
2
δ H (‰)
-70
VFS
C
-75
R-M
-80
Flagstaff MWL
δ2H = 6*δ18O - 14
-85
Flagstaff winter
precipitation
-90
Grand Canyon
winter
precipitation
-95
-100
-15
-14
-13
-12
-11
-10
-9
-8
18
δ O (‰)
Figure 6: Groundwater medians and ranges, with individual data points shown as smaller
circles in the appropriate color. Data points include data from Blasch et al., 2006 and
Rice, 2007, though the medians shown represent data from this study only (with the
exception of Black Hills data due to low sample number (n = 3)). Verde Valley,
Flagstaff, and Grand Canyon winter precipitation averages shown for comparison (data
from Blasch et al., 2006 and Bills et al., 2007). Summer precipitation averages plot in a
much higher isotopic range and thus are not shown here. GMWL plotted according to
Rozanski et al., 1993, and Flagstaff MWL plotted according to Blasch et al., 2006.
difficult to distinguish isotopically from R-M aquifer groundwater, though C
groundwater occupies a wider range of values. Both aquifers’ median δ18O and δ2H are
lower than the Flagstaff winter precipitation average, and both aquifers’ waters plot
above the GMWL and Flagstaff MWL (FMWL). Verde Formation groundwater values
span a large range that includes the range of C and R-M values, though the median Verde
42
Formation stable isotopic value is relatively higher and very similar to the Flagstaff
winter precipitation average. Groundwater from the alluvium aquifer also has a relatively
large range of isotopic values which overlaps the upper end of the Verde Formation
range, and plots along the FMWL with a slight evaporative trend (slope = 4.1). Spring
water from the Black Hills roughly parallels the alluvium range, with slightly greater δ2H
values.
Overall spatial distribution of stable isotopic values shows lower values present
in groundwater samples from wells and springs in the higher-elevation northeast region
of the study area (Figure 7). This region is dominated by wells completed in the C and
R-M aquifers. Two outliers exist within the C-aquifer dataset—these groundwater
samples have the highest isotopic values of the samples collected in this study (both δ18O
= -8.5; δ2H = -67.2, -68.0). It is possible these values reflect a local lower elevation
recharge source for the C aquifer in the southern part of the study area.
Verde Formation aquifer groundwater has a wide range of stable isotopic values,
which can be split into two unique populations based on spatial distribution. The two
populations will be referred to hereafter as the subaquifers Verde Formation North (VFN)
and Verde Formation South (VFS). VFN encompasses the area from Clarkdale southeast
to the Rimrock area, which includes the northern part of the Verde River within the study
area, lower Oak Creek, and lower Wet Beaver Creek (see Figure 2). VFS is comprised of
the area from Route I-17 south to below Camp Verde, which includes the southern part of
the Verde River, and lower West Clear Creek. Within the Verde Formation, stable
isotopic values are generally lowest in the VFN region, whereas the values are highest in
43
Figure 7: Spatial patterns of δ18O values in groundwater.
the VFS region, with some variation in the transition area between the two populations.
Outliers within the VFN population—those points isotopically similar to VFS values—
44
are from wells located close to the river and likely reflect the influence of surface-water
recharge from the river.
Stable Isotope Analysis: Surface water
Surface-water stable isotopic values show both temporal and spatial variation, and
fall within the groundwater range of values (see Table 3). Temporal trends can be
identified by comparison of the three sampling seasons (Figure 8). Verde River summer
(June 2007) isotopic values fall along a line with a slope of 3.3 indicative of evaporation.
-70.0
FMWL
GMWL
-74.0
WCC (Jun-07)
y = 5.4x - 20.3
R2 = 0.95
-78.0
2
δ H (‰)
VR (Jun-07)
y = 3.3x - 42.3
R2 = 0.80
WBC (Jun-07)
y = 5.7x - 18.2
R2 = 0.95
-82.0
-86.0
-12.0
November 2006
OC (Jun-07)
y = 4.5x - 31.6
R2 = 0.46
-11.5
June 2007
February/March 2008
Verde River
Verde River
Verde River
Oak Creek
Oak Creek
Oak Creek
Wet Beaver Creek
Wet Beaver Creek
Wet Beaver Creek
West Clear Creek
West Clear Creek
+ IAEA Flagstaff winter precipitation
-11.0
-10.5
18
δ O (‰)
-10.0
-9.5
-9.0
Figure 8: Temporal trends in surface-water stable isotopic data for the three sampling
campaigns. Summer evaporative trends plot away from the meteoric water lines.
Flagstaff winter precipitation average is shown for comparison.
45
Spring snowmelt (February/March 2008) values occupy a narrower range at the lower
end of this spectrum. Winter base-flow conditions, represented by November 2006
samples, are characterized by isotopic values in the middle range between the other
seasonal populations. Oak Creek samples occupy the lowest end of the surface-water
stable isotopic spectrum. Spring snowmelt values for lower Oak Creek (n=4) are
indistinguishable from winter base-flow values for the same sites, though summer
samples exhibit an evaporation signal similar to that of the Verde River (slope = 4.5).
Wet Beaver Creek winter base-flow values fall between those of Oak Creek and Verde
River. A less pronounced evaporation signal is present in summer samples compared to
the other two streams (slope = 5.7). Insufficient spring snowmelt data (n=1) exists for
comparisons to be made.
Comprehensive discharge data collected by the USGS for the Verde River and its
tributaries during a June 2007 sampling campaign allows for assessment of the impacts of
flow variations on river chemistry (Figures 9 and 10; units in cfs). Significant decreases
in discharge occur along the Verde River where seven ditch diversions are located; stable
isotopic values for the summer samples increase at these locations, reflecting evaporation
of the water remaining in-stream. Several ditch return flows were noted (n=11), and
range in magnitude from 0.3 to 16.2 cfs. In contrast, during the winter when diversions
are minimal, Verde River and Oak Creek isotopic values display less variation.
Overall spatial trends in surface-water stable isotopic data show the lowest values
entering the Verde Valley Basin from the Coconino Plateau in the form of Oak Creek
46
OC
80
WBC
WCC
-9.0
VR (Nov-06)
VR (Jun-07)
70
4
60
-10.0
5
50
2
40
-10.5
30
δ18O ( ‰)
Discharge (cfs)
-9.5
Jun-07 discharge
1
-11.0
7
6
20
3
-11.5
10
0
-12.0
80
70
60
50
40
30
20
10
0
Distance upstream from Verde River near Camp Verde (km)
Figure 9: Discharge data for the Verde River (data collected by USGS) during the June
2007 sampling period, shown with δ18O values for both November 2006 and June 2007.
Major decreases in discharge are associated with ditch diversions (1: Tavasci Ditch, 2:
Hickey Ditch, 3: Cottonwood Ditch, 4: OK Ditch, 5: Eureka Ditch, 6: Woods (Verde)
Ditch, 7: Beasley Flat Ditch). Significant decreases in discharge (e.g., those occurring at
kms 65 and 32) are accompanied by increases in Jun-07 δ18O values. Tributary
confluences are marked (dashed vertical lines), occurring at 44km (OC), 24km (WBC),
and 13km (WCC) upstream from USGS gage 09506000.
water, with slightly higher values entering from Wet Beaver Creek, followed by the
highest values in the Verde River itself. Verde River winter base-flow isotopic values
decrease where these tributaries enter. This is also true for the summer dataset, but the
isotopic changes where Wet Beaver Creek and West Clear Creek enter cannot be
attributed to the addition of surface water, as discharge values at both tributary mouths
were 0 cfs during the summer sampling period due to diversions.
47
80
-9.0
OC (Nov-06)
OC (Jun-07)
70
Jun-07 discharge
-9.5
-10.0
50
40
-10.5
30
δ18O ( ‰)
Discharge (cfs)
60
-11.0
20
PS
-11.5
10
0
-12.0
120
80
100
80
60
40
20
0
-9.0
Distance upstream from Verde River near Camp Verde (km)
WBC (Nov-06)
70
WBC (Jun-07)
-9.5
Jun-07 discharge
-10.0
50
40
-10.5
30
δ18O ( ‰)
Discharge (cfs)
60
-11.0
20
-11.5
10
0
-12.0
120
80
100
80
60
40
20
0
-9.0
Distance upstream from Verde River near Camp Verde (km)
WCC (Nov-06)
WCC (Jun-07)
70
Jun-07 discharge
-9.5
-10.0
50
-10.5
40
30
δ18O ( ‰)
Discharge (cfs)
60
-11.0
20
-11.5
10
0
-12.0
120
100
80
60
40
20
0
Distance upstream from Verde River near Camp Verde (km)
Figure 10: Discharge and δ18O values for the Verde River’s tributaries (discharge data
collected by USGS) during the June 2007 sampling period (Nov-06 δ18O values also
shown). Page Springs causes a significant increase in Oak Creek discharge (PS),
accompanied by an initial decrease in δ18O. Both WBC and WCC were dry at their
confluences with the Verde River during June 2007 sampling; WCC δ18O values show a
clear increase corresponding to the decrease in flow.
48
The surface-water stable isotopic values approximately follow the FMWL (with
departures from the line evident in the evaporated summer samples), and like
groundwater are isotopically most similar to winter precipitation falling in the Flagstaff
region (Figure 11). Winter base-flow values more consistently align with the ranges of
groundwater signatures than the summer dataset due to the non-conservative stable
isotopic behavior of the summer dataset. For the winter dataset, Oak Creek stable
isotopic values plot completely within the range of C and R-M groundwater values,
whereas Wet Beaver Creek values plot over a wider range of relatively heavier isotopic
signatures. Verde River values are greater than the tributaries’ values overall, with a
GMWL
-68
FMWL
Black Hills
VFN
-76
Alluvium
2
δ H (‰)
-72
-80
VFS
C
November 2006
-84
Verde River
Oak Creek
Wet Beaver Creek
West Clear Creek
R-M
-88
-12.0
-11.5
-11.0
-10.5
-10.0
-9.5
June 2007
Verde River
Oak Creek
Wet Beaver Creek
West Clear Creek
-9.0
18
δ O (‰)
Figure 11: Surface-water stable isotopic data compared to the isotopic ranges of
groundwater within the study area.
-8.5
49
range overlapping the VFN, VFS, Black Hills, and alluvium signatures. Of note is the
fact that the alluvium range coincides with a majority of the Verde River summer data
points.
Solute Analysis: Groundwater
Groundwater solute concentrations reveal further differences in aquifer
geochemistry and thus can aid in flow-path delineation. Concentrations of the anions
bromide, chloride, and sulfate vary by aquifer (Table 4). C-aquifer groundwater is
characterized by the lowest concentration of each constituent. Groundwater from the RM aquifer has slightly greater concentrations of all anions. As in the stable isotopic
analysis, two spatial populations within the Verde Formation emerge. Alluvium and
VFN groundwater exhibit intermediate concentrations of each anion, whereas VFS
groundwater is characterized by the highest Cl and SO4 concentrations and a relatively
high Br concentration. Limited data for springs sourced from the Black Hills are high in
Br and SO4, but low in Cl.
Major cation concentrations further distinguish aquifer geochemistry:
concentrations of calcium, sodium, and strontium vary by aquifer (Table 5).
Groundwater from the C aquifer is again characterized by the lowest concentration of
each constituent, with R-M groundwater slightly more concentrated. Similar to the anion
analysis, alluvium and VFN groundwater occupy the intermediate range of cation
concentrations. VFS groundwater has distinctly high concentrations of Na and Sr; both it
and Black Hills spring water have high median Ca concentrations.
50
Table 4: Medians and standard deviations of anion concentrations in groundwaters of the
middle Verde River watershed (* additional data from Blasch et al., 2006; Rice, 2007).
Median (mg/L)
Standard deviation (mg/L)
n
Br
Cl
SO4
Br
Cl
SO4
Northeast
C 17
0.031
7.5
4.1
0.029
10.0
3.26
R-M
4
0.111
38.3
10.1
0.094
42.2
5.31
Valley
Alluvium
5
0.096
23.6
39.4
0.011
19.4
53.8
Verde Fm 36
0.088
29.0
20.0
0.091
59.0
142
VFN 25
0.080
28.1
10.5
0.067
42.6
23.8
VFS 10
0.153
61.3
162
0.123
83.1
207
Southwest
Black Hills* 14
0.156
17.0
54.0
0.07
12.0
52.0
Table 5: Medians and standard deviations of cation concentrations in groundwaters of
the middle Verde River watershed (* additional data from Blasch et al., 2006; Rice,
2007).
Median (mg/L)
Standard deviation (mg/L)
n
Ca
Na
Sr
Ca
Na
Sr
Northeast
C 17
47.3
10.6
0.13
11.8
14.5
0.12
R-M
4
67.2
20.4
0.28
19.4
18.0
0.16
Valley
Alluvium
5
67.7
32.2
1.3
14.3
30.3
1.9
Verde Fm 36
60.3
50.2
0.44
32.0
89.3
5.1
VFN 24
55.8
25.6
0.32
31.3
43.8
0.17
VFS 10
71.4
88.1
5.59
32.3
132.8
7.36
Southwest
Black Hills* 13
72.0
25.0
0.59
28.8
15.2
0.26
Combining these differences, anion and cation ratios of these elements can serve
to distinguish aquifer geochemistry (Figure 12). Groundwater sourced from the C and RM aquifers generally have relatively low SO4/Cl ratios and high Ca/Sr ratios (SO4/Cl: 0
to 0.6; Ca/Sr: 147 to 516). Of the groundwater groups, Verde Formation groundwater
has the largest range of SO4/Cl and Ca/Sr ratios (SO4/Cl: 0.14 to 9.1; Ca/Sr: 2.9 to 460),
51
with median values of 0.51 and 134, respectively. The two Verde Formation
groundwater populations recognized in the stable isotopic data are again clearly distinct.
VFN groundwater occupies the range of lower SO4/Cl values (0 to 1.6) and higher Ca/Sr
values (80 to 312). These waters overlap with the C and R-M aquifer range of ratios.
Contrastingly, VFS groundwater solute ratios span a distinct range of higher SO4/Cl
values (1.1 to 9.1) and low Ca/Sr values (0 to 88).
600
Alluvium
Black Hills
VFN
VFS
C
R-M
500
Ca/Sr ratio (wt/wt)
C
400
R-M
VFN
300
(10.9, 241)
200
VFS
100
(9.1, 2.9)
0
0.0
0.5
1.0
1.5
2.0
2.5
3.0
3.5
4.0
4.5
SO4/Cl ratio (wt/wt)
Figure 12: Ca/Sr and SO4/Cl ratios of groundwater are useful for distinguishing different
aquifer sources.
Solute Analysis: Surface water
Based on surface-water solute concentration patterns the Verde River can be
analyzed in terms of four distinct reaches, and Oak Creek and Wet Beaver Creek can be
52
discussed in terms of upper and lower reaches. Reach 1 is the section of the Verde River
between kilometers 82 and 66 (from the Sycamore Creek confluence to Clarkdale); in
this reach the Verde River first enters the Verde Formation area. Geochemically different
from reach 1, reach 2 is the length of the Verde River between kilometers 66 and 45
(Cottonwood to Oak Creek). Reach 3 spans from Oak Creek to route I-17 (kms 45 to 30)
and receives a significant input of water from this tributary. Downstream of I-17 to the
USGS gage 09506000, reach 4 has a distinct geochemical composition and is
geographically coincident with the VFS subaquifer.
Br, Cl, and SO4 concentrations vary over distance (Figure 13). The chemical
evolution of Verde River water downstream consists of overall increases in Cl and SO4,
with pronounced increases (between kilometers 68 to 60 and 32 to 13) contained within
reaches 2 and 4. River water in reaches 1 and 3 is comparatively dilute and exhibits little
change. Oak Creek water has relatively uniform concentrations of Cl, Br, and SO4 in a
downstream direction until km 80, where an increase in all three constituents occurs
followed by a slight decline. Wet Beaver Creek anion concentrations exhibit an increase
in solutes downstream of km 50. Where the tributaries enter the Verde River, the river’s
anion concentrations reflect the chemical signature of the input (at Oak Creek confluence:
concentrations are diluted; at Wet Beaver Creek confluence: concentrations increase).
Overall anion relationships reveal distinct trends for the Verde River and its
tributaries. The Verde River’s chemistry indicates a clear positive correlation between
SO4 and Cl with a winter base-flow slope of 4.8 (r2 = 0.94), whereas tributary data exhibit
a separate positive trend with a much lower slope of 0.20 (r2 = 0.97 for Oak Creek
53
0.12
1
Sycamore Creek
2
0.18
4
3
0.10
3
4
Oak Creek
BH
VFS
Wet Beaver Creek
Oak Creek
0.14
Wet Beaver Creek
0.08
2
1
Verde River
0.16
Verde River
West Clear Creek
West Clear Creek
0.12
Br (mg/l)
Br (mg/l)
R-M
0.06
0.04
0.10
A
0.08
VFN
0.06
0.04
0.02
C
0.02
0.00
140
30
120
100
80
60
40
20
0.00
120
80
0
Distance
upstream from Verde
Camp 3Verde (km) 4
Sycamore
Creek
1 River near
2
Verde River
25
70
Oak Creek
Wet Beaver Creek
80
60
40
20
0
VFS
60
West Clear Creek
50
Cl (mg/l)
Cl (mg/l)
20
100
Verde
River upstream from
1
2
3
4
Distance
Verde River
near Camp
Verde (km)
Oak Creek
Wet Beaver Creek
West Clear Creek
15
40
R-M
30
10
VFN
A
20
5
0
140
70
60
10
120
100
80
60
40
20
0
120
300
0
Sycamore
1
2
DistanceCreek
upstream from Verde
River near
Camp3Verde (km) 4
Verde River
Oak Creek
Wet Beaver Creek
West Clear Creek
250
C
100
80
60
40
20
0
Verde
River upstream from
1
2
3
4
Distance
Verde River
near Camp
Verde (km)
Oak Creek
Wet Beaver Creek
West Clear Creek
200
40
SO4 (mg/l)
SO4 (mg/l)
50
BH
30
VFS
150
100
20
0
140
BH
A
50
10
120
100
80
60
40
20
Distance upstream from Verde River near Camp Verde (km)
0
0
120
VFN, R-M
C
100
80
60
40
20
0
Distance upstream from Verde River near Camp Verde (km)
(A)
(B)
Figure 13: Br, Cl, and SO4 concentrations as a function of distance for the winter (A) and
summer (B) datasets. The Verde River is divided into four reaches based on locations of
significant changes in the river’s geochemical composition. Median groundwater
compositions (horizontal dashed lines) are shown for comparison in (B).
samples; Figure 14A). Summer data exhibit a similar trend distinction, but with slightly
different slopes (Figure 14B). A projection of the distinct Verde River trend in both
seasonal datasets enters the geochemical space near the potential VFS end member. With
the exception of one high-sulfate summer outlier in reach 2 (sample VR-16), Reach
54
300
250
SO4 (mg/l)
200
VR: R1
Precipitation (winter)
VR: R2
Alluvium
VR: R3
BH
VR: R4
VFN
OC
VFS
WBC
C
WCC
R-M
Verde River
y = 4.8x - 53.3
R2 = 0.94
150
100
Oak Creek
y = 0.20x + 0.70
R2 = 0.97
50
MW
PS
0
0
10
20
30
40
50
60
70
80
70
80
Cl (mg/l)
(A)
300
VR: R1
VR: R2
VR: R3
VR: R4
OC
WBC
WCC
Precipitation (winter)
Alluvium
BH
VFN
VFS
C
R-M
250
SO4 (mg/l)
200
150
VR-16
Verde River
y = 3.8x - 30.3
2
R = 0.74
100
Oak Creek
y = 0.12x + 0.69
2
R = 0.76
50
MW
PS
0
0
10
20
30
40
50
60
Cl (mg/l)
(B)
Figure 14: Trends in the relationship between SO4 and Cl for winter (A) and summer (B)
data. Diamonds represent surface-water samples whereas circles represent median values
for different groundwater end members. The Verde River has a distinctly different trend
compared to that of the tributaries. Verde River water increases in both anion
concentrations in the downstream direction (reach 4 has the highest concentrations).
55
4 exhibits the highest sulfate and chloride concentrations. The trend-line for Oak Creek
and Wet Beaver Creek samples spans a range of SO4 and Cl values between those of
average winter precipitation and the C and R-M aquifer groundwater signatures.
The distinction of the four Verde River reaches and the upper and lower reaches
of Oak Creek and Wet Beaver Creek is also evident in the spatial trends of cation
concentrations (Figure 15). Ca, Na, and Sr concentrations are generally constant along
the length of Oak Creek downstream until kilometer 80, where all three concentrations
increase before declining slightly again. Along Wet Beaver Creek, Na and Sr
concentrations show a notable increase near km 55. The Verde River shows a notable
overall increase in Na and Sr concentrations traveling downstream toward Camp Verde.
Significant Na and Sr increases occur in reaches 2 and 4, though reach 2 increases are
less dramatic than those observed for Cl and SO4. Where confluences with tributaries
occur, the main river’s chemistry reflects the addition of tributary water. Along the reach
downstream from the Oak Creek confluence (reach 3), Verde River chemistry reflects the
lower Na and Sr concentration input, and in reach 4 where Wet Beaver Creek becomes an
input, Verde River Na and Sr increase, but this is likely a reflection of groundwater input
considering the WBC input has lower concentrations.
An examination of the combined SO4/Cl and Ca/Sr ratios of surface water adds
context to groundwater-surface water interactions (Figure 16). Oak Creek values are
entirely encompassed by the range characteristic of C and R-M groundwater. Wet
Beaver Creek values span a range overlapping that of the C and R-M aquifers (low
SO4/Cl, high Ca/Sr) and that of the VFN. Verde River values range between the two
56
Verde Formation populations. Spatially, this range tends from low SO4/Cl and high
Ca/Sr values upstream toward the opposite composition downstream (Figure 17).
Distinct chemical shifts occur in reach 2 (both SO4/Cl and Ca/Sr ratios increase) and
70
60
2
1
1
4
3
2
3
4
80
VFS, BH
A R-M
70
60
40
Ca (mg/l)
Ca (mg/l)
50
90
Sycamore Creek
Verde River
Oak Creek
Wet Beaver Creek
West Clear Creek
30
VFN
50
C
40
30
20
20
0
140
45
40
10
120
100
80
60
40
20
0
120
180
0
Sycamore
DistanceCreek
upstream from Verde
River2near Camp
1
3 Verde (km)4
Verde River
160
140
Wet Beaver Creek
West Clear Creek
25
20
60
40
5
20
0.6
100
80
60
40
20
0
120
6
0
DistanceCreek
upstream from Verde
River2near Camp
Sycamore
1
3 Verde (km)4
Verde River
5
Oak Creek
Wet Beaver Creek
West Clear Creek
60
40
20
0
West Clear Creek
VFS
A
BH,VFN
R-M
C
100
80
60
40
20
0
1
2
3
4
Distance upstream from
Verde River
near Camp
Verde (km)
VFS
Verde River
Oak Creek
Wet Beaver Creek
West Clear Creek
4
0.4
Sr (mg/l)
Sr (mg/l)
0.5
80
80
10
120
100
Distance
Verde River
near Camp
Verde (km)
Verde
Riverupstream from
1
2
3
4
Oak Creek
100
15
0
140
0.7
West Clear Creek
120
Na (mg/l)
Na (mg/l)
30
Wet Beaver Creek
Wet Beaver Creek
Oak Creek
35
Verde River
Oak Creek
10
0.3
3
2
0.2
0
140
A
1
0.1
120
100
80
60
40
20
Distance upstream from Verde River near Camp Verde (km)
0
0
120
BH
R-M, VFN
C
100
80
60
40
20
0
Distance upstream from Verde River near Camp Verde (km)
(A)
(B)
Figure 15: Ca, Na, and Sr concentrations as a function of distance for the winter (A) and
summer (B) datasets. The behavior of the four reaches and upper and lower tributary
reaches is similar to that observed in Figure 13. Median groundwater compositions
(horizontal dashed lines) are shown for comparison in (B).
57
600
C
500
Ca/Sr ratio (wt/wt)
Surface water
VR (Nov-06)
VR (Jun-07)
OC (Nov-06)
OC (Jun-07)
WBC (Nov-06)
WBC (Jun-07)
WCC (Nov-06)
WCC (Jun-07)
400
300
Groundwater median
Alluvium
BH
Verde Formation
VFN
VFS
C
R-M
VFN
R-M
200
VFS
100
0
0.0
0.5
1.0
1.5
2.0
2.5
3.0
3.5
4.0
4.5
SO4/Cl ratio (wt/wt)
Figure 16: Comparison of surface-water to groundwater Ca/Sr and SO4/Cl ratios.
Notably, nearly all tributary points plot within the ranges for C and R-M groundwater.
The Verde River spans a range between these and the VFS subaquifer range. A number
of Verde River samples do not plot fully within the range of groundwater values.
reach 4 (SO4/Cl increases while Ca/Sr decreases). In contrast, Oak Creek and Wet
Beaver Creek SO4/Cl values are relatively constant over their lengths. Ca/Sr values trend
slightly negatively from upstream to downstream along Oak Creek, and are variable
along Wet Beaver Creek.
80
60
40
20
4
A
1.0
1.5
2.0
2.5
VFS
3.0
3.5
BH
4.0
120
100
80
60
40
20
(A)
Distance upstream from Verde River near Camp Verde (km)
0
VFS
0
A 50
100
100
80
60
2
(64.4, 13.2)
40
3
20
120
80
60
40
20
(B)
Distance upstream from Verde River near Camp Verde (km)
100
West Clear Creek
Wet Beaver Creek
Oak Creek
Verde River
0
VFS
A
VFN
R-M
BH
C
0
C
VFN
R-M
A
VFS
BH
(13.3, 15.3)
4
Distance upstream from1 Verde River
Verde (km)
2 near Camp
3
4
120
West Clear Creek
Wet Beaver Creek
Oak Creek
Verde River
1
Figure 17: An examination of SO4/Cl and Ca/Sr ratios as a function of distance for the winter (A) and summer (B) datasets.
The distinctions in the four Verde River reaches are clear: reaches 1 and 3 are each relatively uniform in geochemical
composition, whereas reaches 2 and 4 involve significant shifts.
0
50
100
150
200
VFN
150
200
300
C
350
400
450
500
R-M
250
BH
Sycamore Creek
Verde River
Oak Creek
Wet Beaver Creek
West Clear Creek
2 near Camp
3 Verde (km)4
Distance upstream from1Verde River
250
300
350
400
450
500
0
0.0
100
3
0.0
2
C 0.5
VFN
R-M
120
West Clear Creek
Wet Beaver Creek
Oak Creek
Verde River
1
0.5
1.0
1.5
2.0
2.5
3.0
3.5
Sycamore Creek
Ca/Sr ratio (wt/wt)
SO4/Cl ratio (wt/wt)
Ca/Sr ratio (wt/wt)
SO4/Cl ratio (wt/wt)
4.0
58
59
Radioactive Isotope Analysis: Groundwater
Tritium concentrations for the selected groundwater samples range from 0.6 to 4.6
TU (n=12; Figure 18). Groundwater from the Verde Formation comprises 11 of the 12
samples; the remaining sample is from the C aquifer. This sampling bias is based on the
assumption that groundwater samples from the C and R-M aquifers are mainly recharged
prior to 1952 and thus would not contain detectable tritium. Qualitative analysis of
tritium concentrations allows for a classification of the results into three residence time
categories based on those determined by Clark and Fritz (1997) (Table 6). This results in
3 ‘Submodern’ samples, 8 ‘Mixed’ samples, and 1 ‘Recent’ groundwater sample.
Submodern groundwater (recharged prior to 1952) is found within the region
encompassing Page Springs and the Oak Creek confluence. All three submodern samples
are from the Verde Formation. Though nearby Spring Creek is considered mixed water
(3H: 1.5 ± 0.39 TU; Rice, 2007), spring water issuing from Page Springs (sample
VG10050705) is submodern. Near the confluence between Oak Creek and the Verde
River, a well ~100 m north of Oak Creek (depth: 26 m) also contains submodern water.
On the west side of the Verde River south of Cottonwood and Route 89A, groundwater
from a well ~200 m from the river is submodern (well depth: 72 m).
‘Mixed’ groundwater samples (mixtures between submodern and recent recharge)
are also sourced from the Verde Formation, and range spatially from Cottonwood south
to Camp Verde. Several wells in this population overlap the spatial range of submodern
groundwater. A well south of Page Springs near Cornville is <100 m from Oak Creek
and contains groundwater at the upper end of the ‘mixed’ groundwater spectrum (3.0 ±
60
A
B
Figure 18: Spatial distribution of tritium concentrations and carbon-14 values measured
for selected groundwater samples (n=12 and n=10, respectively). Carbon-14 values are
marked. Two transects are demarcated for discussion of residence times in well groups
that are parallel (A) and perpendicular (B) to regional groundwater flow.
61
Table 6: Summary of tritium results and interpreted qualitative residence times.
Classification based on Clark and Fritz (1997); S = Submodern (<0.8 TU; recharged prior
to 1952), M = Mixture between submodern and recent recharge (0.8 to 4 TU); R = Recent
recharge (5 to 15 TU; <5 to 10 yr).
Sample ID
3
UTM N
(NAD83)
UTM E
(NAD83)
Source
Aquifer
Well depth
(m)
H
(TU)
Submodern
VG10050705
VG10070702
VG10070705
3846974
3840993
3838111
418621
409709
414298
Verde
Verde
Verde
0
72
26
0.6 ± 0.26
0.7 ± 0.29
0.6 ± 0.22
Mixed
VG11170602
VG11170603
VG10050703
VG10070704
VG10070706
VG10060702
VG09110703
VG10050702
3845854
3846059
3845321
3840420
3838089
3824222
3822174
3819684
408419
407339
411212
416053
414178
420618
422218
422566
Verde
Verde
Verde
Verde
Verde
Verde
Verde
Verde
44
110
73
67
9
55
30
30
0.8 ± 0.26
1.0 ± 0.30
1.3 ± 0.28
3.0 ± 0.35
1.7 ± 0.27
1.0 ± 0.30
2.3 ± 0.41
1.7 ± 0.24
Recent
VG10060706
3865492
432629
C
30
4.6 ± 0.40
0.35 TU; well depth 67 m). A second well near the Oak Creek confluence is <100m from
the creek (but is shallower than the aforementioned well containing submodern water)
and contains mixed groundwater (well depth: 9 m). The two samples analyzed from
Cottonwood (VG11170602 and VG11170603) are ~1.1 km apart and vary in depth (44
and 110 m, respectively), but their tritium concentrations are nearly indistinguishable.
East of Cottonwood along Route 89A, a Verde Formation sample contains a slightly
larger component of recent recharge than these Cottonwood wells (3H: 1.3 ± 0.28 TU;
depth = 73 m). Finally, all three wells analyzed for tritium concentration in the Camp
62
Verde area are mixed (well depths: 30 to 55 m), with a range of tritium concentrations
between 1.0 and 2.3 TU.
The only groundwater sample to be classified as ‘Recent’ (<5 to 10 years
residence time) is sourced from the C aquifer, from a relatively shallow well only ~200 m
east of Oak Creek (depth: 30 m).
Carbon-14 values range from 28.48 to 80.80 pmC (n=10; Figure 18, Table 7).
Without correction for the influence of carbonate dissolution or organic matter oxidation,
the corresponding residence time calculations can be assumed to represent the maximum
of the range of possible values. Groundwater residence times increase from northeast to
southwest along transect A (parallel to regional flow) from Sedona (C and R-M) to
Cottonwood (VFN). Uncorrected groundwater residence times north of Sedona are on
the order of 1,700 to 7,100 years (14C = 80.80 to 41.33 pMC); near Cottonwood they are
on the order of 10,000 years (14C = 28.48, 28.72 pMC). The Cottonwood wells have low
but detectable tritium levels (0.8 and 1.0 TU), indicating the water there is a mixture of
younger water with relatively long-residence time water.
Table 7: Summary of δ13C and carbon-14 results. Uncorrected ages are given in years
before present (BP).
Sample ID
VG11170603
VG10050703
VG09100702
VG09100704
VG10050705
VG10070703
VG10050708
VG10060705
VG10050702
VG11170605
UTM N
(NAD83)
3846262
3845321
3849717
3848917
3846974
3856213
3863704
3832067
3819684
3852729
UTM E
(NAD83)
407274
411212
428819
431168
418621
420935
424591
427108
422566
424027
Source
Aquifer
Verde
Verde
R-M
C
Verde
C
R-M
Verde
Verde
C
Well depth
(m)
110
73
183
250
0
197
309
unknown
30
213
δ13C
(‰)
-7.7
-8.6
-9.0
-10.7
-10.2
-10.0
-12.4
-8.9
-10.7
-11.1
14
C
(pMC)
28.48 ± 0.19
28.72 ± 0.19
34.20 ± 0.23
38.68 ± 0.22
38.93 ± 0.22
41.33 ± 0.23
55.94 ± 0.27
66.09 ± 0.87
77.67 ± 0.34
80.80 ± 0.35
Uncorrected Age
(years BP)
10,091 ± 52
10,023 ± 51
8,619 ± 53
7,631 ± 45
7,578 ± 45
7,098 ± 43
4,666 ± 39
3,330 ± 110
2,030 ± 35
1,712 ± 34
63
Groundwater from wells along transect B (perpendicular to regional flow; well
depths: 183 to 250 m), have 14C values ranging from 34.20 to 41.33 pMC (8,619 to 7,098
yBP) with the exception of a sample located less than 200 m from Oak Creek having a
value of 80.80 pMC (well depth: 213 m). Given the relative uniformity of 14C values
over transect B, this sample’s relatively high value is a likely result of ‘modern’ surface
water infiltration from Oak Creek. Groundwater from the two wells at either end of
transect B have similar 14C values (west: 41.33, and east: 38.68 pMC); these wells are
both completed in the C aquifer at depths of 197 m and 250 m, respectively. In contrast,
the well on this transect with the lowest 14C value (34.20 pMC) is from the R-M aquifer
at a depth of 183 m. Groundwater from Page Springs has a similar 14C value to the wells
on transect B (38.93 pMC).
Besides the high-14C sample along transect B, the highest 14C values in
groundwater appear in the Rimrock (14C = 66.09 pMC) and Camp Verde (14C = 77.67
pMC) areas. The analyzed Camp Verde well (depth: 30 m) has detectable tritium
indicative of groundwater of mixed residence-time origin (3H = 1.7 TU).
64
DISCUSSION
What is the nature of aquifer connectivity in the middle Verde River watershed?
The C, R-M, and Verde Formation aquifers
The results of this geochemical study provide a better understanding of the
characteristics of and connectivity between the three main aquifers storing groundwater
in the middle Verde River watershed. Specifically, the results enable distinctions and
comparisons in groundwater composition to be made, allowing for a discussion of
groundwater mixing. The outcome is an improved conceptual model of the watershed’s
hydrogeology.
A significant finding of this study concerns the groundwater mixing that occurs in
the northern and middle regions of the study area. In these areas, the C and R-M aquifers
are hydrologically connected to the Verde Formation aquifer. This connection is
evidenced by the geochemical similarities between Verde Formation groundwater and C
and R-M groundwater, as well as by the results of radioactive isotope analysis. Based on
the location and elevational differences of the aquifers, a reasonable prediction of the
stable isotopic composition of Verde Formation groundwater would be higher δ2H and
δ18O values relative to those of the C and R-M aquifers. However, groundwater in the
northern part of the Verde Formation has a relatively low isotopic signature suggestive of
connectivity between it and the plateau-recharged C and R-M aquifers (see Figures 6-7).
This connection is further evidenced by the results of solute concentration and
ratio analyses. While groundwater from the C aquifer is distinguishable based on its
relatively dilute chemical composition, R-M and VFN groundwater both have higher
65
concentrations and similar geochemical characteristics. This likeness between R-M and
VFN groundwater is consistent with hydrologic connection between the two aquifers
along a northwest-southeast transect containing the Page Springs and associated faults.
At Page Springs and Montezuma’s Well, where spring water discharges from the Verde
Formation, this connection is especially evident in the geochemical similarities of Page
Springs water to C groundwater and Montezuma’s Well water to R-M groundwater (see
Figure 14). Additionally, water issuing from Page Springs has a residence time
comparable to those calculated for wells on the northwest—southeast Sedona transect.
Similar results have been observed for other springs in the faulted region, notably Spring
Creek and Russell Spring (Rice, 2007). It is thus probable that some amount of C and RM groundwater is transmitted in the subsurface along these faults, though this would be a
local effect while the widespread similarity of VFN groundwater to R-M groundwater in
particular indicates that these faults are not wholly responsible for this mixing.
Quantifying the groundwater fluxes across these faults is beyond the scope of this study;
in order to do so, it would be necessary to obtain a greater sampling density of wells in
known locations on both sides of specific faults.
The results of 3H and 14C analyses reinforce the regional groundwater conceptual
model, and provide further evidence for the hydrologic connection existing between the
C and R-M aquifers and the northern portion of the Verde Formation. Tritium and
carbon-14 results show the oldest waters existing in the area around Cottonwood, Page
Springs, and the Oak Creek confluence (except in the case of the well with relatively
young water likely due to infiltration from Oak Creek). Carbon-14 results additionally
66
show that groundwater in the VFN subaquifer tends to have longer residence times than
groundwater in the VFS subaquifer. These samples have a relatively long residence time
consistent with waters that have traveled from a recharge source on the Colorado Plateau
through the Paleozoic aquifers. Some of these waters have mixed with a smaller amount
of locally-recharged water (potentially from the Verde River) in the northern part of the
Verde Formation (as evidenced by “mixed” 3H values).
In contrast to VFN groundwater, groundwater from the VFS subaquifer is
geochemically distinct from all other analyzed groundwaters. The comparatively higher
δ2H and δ18O signature of VFS groundwater indicates a lower elevation recharge source,
or the infiltration of surface water (a relatively evaporated source; see Figure 11 and
Table 3). Based on the relatively higher tritium concentrations and high amount of
modern carbon in VFS groundwater compared to VFN groundwater, it is probable that
infiltration of Verde River water is the explanation for the observed groundwater
geochemistry.
Given the relatively high and evaporated stable isotopic composition, high tritium
concentrations, high amount of modern carbon, and significantly higher concentrations of
anions and cations in these waters, it is unlikely that the VFS receives any substantial
groundwater contributions from the C or R-M aquifers. Dissolution of evaporites within
the Verde Formation is a likely source for the elevated concentrations of chloride, sulfate,
sodium, and strontium in VFS groundwater. This finding is consistent with the fact that
the most sediments and evaporites accumulated in the southern part of the Verde Valley
67
near Camp Verde during the formation of this geologic unit (Twenter and Metzger,
1963).
Minor aquifers
Groundwater from the shallow wells in the alluvium aquifer is not geochemically
distinct from either Verde Formation groundwater or Verde River water. In most
bivariate solute plots, the alluvium groundwater plots as a mixture between the two.
These results convey, as would be expected, the connectivity between the alluvium and
both the Verde Formation and the Verde River. Since the alluvium was not a main focus
of this study, a greater sampling density of alluvium groundwater would be necessary for
more conclusive results about regions of connection with the regional aquifer and those
areas sourced from the river as Baillie et al. (2007) performed for the San Pedro River.
Likewise, the results concerning spring water from the Black Hills are lacking due
to limited sampling from this groundwater population. Drawing upon available data from
Blasch et al. (2006) and Rice (2007), generalizations can be made about the geochemical
composition of this spring water, but the geologic units from which these springs
originated varies. Though springs on the eastern flank of the Black Hills are generally
from the Martin Formation (of the R-M aquifer; Owen-Joyce and Bell, 1983), some of
the lower-elevation Black Hills springs in this study appeared to source from the Verde
Formation. The nature of the faulting and stratigraphy of the Black Hills makes it
difficult to discern the flow of water recharged in the Black Hills toward the Verde River,
though it is believed that the Verde Fault Zone obstructs groundwater flow in this
direction (Twenter and Metzger, 1963).
68
What are the sources of base flow to the Verde River?
Analyses performed in this study focus on six potential sources of groundwater to
the Verde River (the C, R-M, Alluvium, VFN, VFS, and Black Hills) in addition to
precipitation and the tributaries. Results of the solute analysis provide some indication of
which groundwater may provide base flow to the Verde River; we can further describe
these sources through principal components analysis, and quantify them using solute ratio
mixing diagrams.
Principal Components Analysis
Normalized chemical data from the Verde River and its potential base-flow
sources were projected into U space based on the eigenvectors produced by principal
components analysis. PCA reveals the distinct river reach groupings (Figure 19). The
summer surface-water data are the focus for this analysis because they include a greater
sampling density in each reach than the winter base-flow dataset (see Appendix B for
November 2006 PCA). For the summer data, the first two principal components account
for 89% of the total variance in the data, with the first principal component accounting
for 75% and the second principal component 14%. An explanation of the principle
components, the percentages of variance explained, and coefficients used for each tracer
is provided in Appendix C.
The relative positions of the four reaches in U space furnish information
concerning the changes in base-flow sources over the length of the Verde River. Reaches
1 and 3 overlap in U space, and show an obvious relationship to waters sourced from the
69
2
4
1
3
Figure 19: PCA results clearly distinguish the four Verde River reaches in the summer
dataset (marked with numbers; for winter dataset PCA see Appendix B). Groundwater
and tributary medians are also plotted in order to evaluate potential sources of flow to the
four reaches.
Colorado Plateau (the tributaries and groundwater from the C and R-M aquifers), as well
as the input of water from the VFN subaquifer. Though reach 2 exhibits a similarity to
VFN and R-M groundwater, it also exhibits a shift toward water with a distinct chemical
composition similar to Black Hills spring water. Finally, reach 4 has a unique position in
U space that approaches the space occupied by VFS groundwater. In order to best
understand how the Verde River chemical composition evolves over its length in the
70
study area, we examined the reaches independently. This examination was done by
modifying the PCA method so that the stream and potential end members’ chemical data
were normalized to each reach’s median composition rather than that of the whole river
length.
Reach 1: 82 to 66 kilometers upstream of Verde River near Camp Verde
(Sycamore Creek to Clarkdale)
Reach 1 data points are tightly clustered in U space (Figure 20A); as evidenced by
the solute analyses (see Figures 13 and 15), reach 1 is geochemically less variable than
the other reaches. The U-space projections of C groundwater, VFN groundwater, and
winter precipitation provide potential boundaries for the reach 1 projections. The ability
of the VFN chemical signature to bound the reach 1 dataset in U-space is logical, as the
Verde River enters the northern part of the Verde Formation at the head of reach 1.
Reach 2: 66 to 45 kilometers upstream of Verde River near Camp Verde
(Cottonwood to Oak Creek)
The Verde River undergoes a geochemical evolution in reach 2 which plots in U
space as a cluster near VFN, R-M, and Black Hills groundwater (Figure 20B). However,
the data cluster is not completely bound by these points, but exhibits a shift toward the Uspace region occupied by sample VR-16 (km 64). VR-16, a highly concentrated sample
(B)
Figure 20: PCA performed for each reach individually (June 2007 data).
(C)
(A)
(D)
71
72
taken from the lowest flow along the reach (the water present in-stream after several
ditches have removed the majority of the river’s flow), seems to represent an undefined
groundwater influx. Evaporation of remaining in-stream river water is supported by the
relatively heavy stable isotopic signature of this water, but is unlikely to be the dominant
cause given this sample’s distinctly high SO4/Cl ratio (due to its high SO4 concentration).
Likewise, local groundwater from the VFN as well as discharge from a nearby spring
(Shea Spring) are not capable of explaining this geochemical shift. One possible source
of the high-sulfate water is reactions related to past mining operations near this location.
Reach 3: 45 to 30 kilometers upstream of Verde River near Camp Verde (Oak
Creek to Route I-17)
Reach 3 plots in similar U space to reach 1 (Figure 20C). This similarity reflects
the major influence on these reaches of Colorado Plateau-derived water, which distinctly
occupies the third quadrant of the PCA figure (Figure 19). For reach 3, this influence
results from the influx of Oak Creek water at the head of the reach (Q = 29.8 cfs added to
the reach 2 inflow of 48.2 cfs). Reach 3 data points appear to be influenced additionally
by water from the R-M, VFN, or alluvium aquifers.
Reach 4: 30 to 0 kilometers upstream of Verde River near Camp Verde (Route I17 to USGS gage 09506000)
Reach 4 distinctly occupies a larger range in U space than the first three reaches
(Figure 20D). A spatial progression occurs in which the upper part of reach 4 plots
73
nearest the reach 3 input composition and it evolves downstream toward the VFS median
composition, with potential inflow from the alluvium aquifer. The influence of VFS
groundwater is logical given that reach 4 is spatially coincident with the VFS subaquifer
as defined in this study. However, the U-space projections of the downstream-most reach
4 samples are not fully bound by the VFS median groundwater projection, which will be
addressed in the mixing analysis.
Solute Ratio Mixing Diagrams
Using the PCA results to identify groundwater end members, potential mixing
scenarios for base-flow water sources can be quantified using solute ratio mixing
diagrams. In an analysis of SO4/Cl ratio versus Cl, mixing curves are calculated between
the potential sources. Percent mixing is then quantifiable based on these end members;
these percentages of flow are translated into groundwater fluxes using the discharge data
collected during the June 2007 sampling period.
Oak Creek and Wet Beaver Creek
As noted in the solute concentration analyses, lower Oak Creek and lower Wet
Beaver Creek have distinctly different chemical compositions compared to their upper
reaches (see Figures 13 and 15). The observed chemical shift occurs when these
tributaries cross the geologic boundary into the Verde formation, a boundary that is
typically associated with a local fault (e.g. Page Springs fault) and the site of large
regional springs.
74
As Oak Creek enters the Verde Formation flow increases from 8.5 cfs to 29.8 cfs
(see Figure 10). A portion of this flow is clearly the result of discharge from Page
Springs which, interestingly, is geochemically similar to C groundwater (Figure 21A).
This composition would indicate that, despite issuing from the Verde Formation, the C
aquifer is the likely water source and that these waters have not resided for a significant
period in the Verde Formation. Furthermore, the geochemical shift of Oak Creek
downstream of Page Springs is such that additional groundwater sources, likely from the
R-M aquifer, must occur independently of this spring source. Based on a mixing line
between the initial upper Oak Creek composition and the R-M aquifer geochemical
signature, lower Oak Creek receives approximately 34% of its flow, translating to 10.1
cfs, from the R-M aquifer (Figure 21A). This implies that of the observed 21.3 cfs
increase, 11.2 cfs originates from Page Springs and 10.1 cfs from R-M aquifer
groundwater discharge. The contribution from Page Springs in considerably less than the
36 to 42 cfs discharge previously measured (Twenter and Metzger, 1963; Levings, 1980)
and may be due to consumptive use associated with a fish hatchery and local home
owners.
Like Oak Creek, Wet Beaver Creek has a significant site of spring discharge —
Montezuma’s Well—which is a likely contributor of groundwater entering the creek in its
lower reach. Similar to Page Springs, Montezuma’s Well issues from the Verde
Formation but as a regional spring it has a geochemical composition similar to R-M
groundwater (Figure 21B). Using a mixing line between the initial upper Wet Beaver
75
(0.11, 4.9)
(17.0, 3.2)
(61.3, 2.6)
(23.6, 1.7)
1.0
Oak Creek
Winter precipitation
Alluvium
BH
VFN
VFS
C
R-M
SO4/Cl ratio (wt/wt)
(A)
0.5
upper OC
Mixing line between initial
OC composition and R-M
PS
below PS
above confluence
lower OC
0.0
0
5
10
15
20
25
30
35
40
Cl (mg/l)
(0.11, 4.9)
(17.0, 3.2)
(61.3, 2.6)
(23.6, 1.7)
1.0
Wet Beaver Creek
Winter precipitation
(B)
Alluvium
BH
SO4/Cl ratio (wt/wt)
VFN
VFS
C
R-M
0.5
Mixing line between initial
WBC composition and R-M
MW
upper WBC
lower WBC
0.0
0
5
10
15
20
25
30
35
40
Cl (mg/l)
Figure 21: Mixing diagrams for June 2007 samples from Oak Creek (A) and Wet Beaver
Creek (B), plotted along with groundwater medians. Potential mixing lines between
initial stream composition and R-M groundwater are shown with 10% increments
(crosses). Page Springs (PS) and Montezuma’s Well (MW) are marked for reference.
Geochemical shifts occur at km 80 for Oak Creek and km 55 for Wet Beaver Creek
(these locations mark where the creeks are divided into “upper” and “lower” reaches).
76
Creek chemistry and the R-M aquifer geochemical signature, this input is approximately
42% of stream flow (Figure 21B). Based on the discharge for Wet Beaver Creek below
Montezuma’s Well (4.7 cfs), this translates to a 2.0 cfs discharge. This value is nearly
the same as the observed increase in flow along this reach (2.2 cfs; see Figure 10) and is
similar to the typical discharge of Montezuma’s Well (mean monthly discharge over the
period 1977-1992: 0.71 to 3.18 cfs; Konieczki and Leake, 1997). Taken together this
implies that Montezuma’s Well is likely the dominant source of groundwater influx to
lower Wet Beaver Creek.
Verde River: Reach 1
Reach 1 can be approached as a mixture of the initial river composition and VFN
groundwater. According to the resultant mixing line, the river gains a minimal influx of
VFN groundwater of 1.1 cfs (2% of the flow; Figure 22A). This minimal occurrence of
groundwater influx is supported by the discharge data, which indicate that the reach is
approximately constant in terms of flow (see Figure 9).
Verde River: Reach 2
The pronounced change in geochemical composition of the Verde River from
reach 1 to reach 2 indicates a shift in base-flow sources. Substantial ditch diversions
leave reach 2 nearly dry in its upper section (see Figure 9), yet the remainder of the reach
recovers from the major decrease of flow even without input from tributaries. Base flow
begins at 58.5 cfs, dropping to 0.3 cfs within 2 km, and recovers to a final flow of 48.2
cfs. Four return flows along the reach were noted and measured, their discharge totaling
77
(0.11, 4.9)
(17.0, 3.2)
VR: Reach 1
Sycamore Creek (Nov-06)
Winter precipitation
Alluvium
BH
VFN
VFS
C
R-M
(A)
SO4/Cl ratio (wt/wt)
(61.3, 2.6)
(23.6, 1.7)
1.0
0.5
Mixing line between initial
R1 composition and VFN
0.0
0
5
10
15
20
25
30
35
40
Cl (mg/l)
(20.9, 13.3)
5
VR: Reach 2
VR Reach 1 input
Return flows
Winter precipitation
Alluvium
BH
VFN
VFS
C
R-M
SO4/Cl ratio (wt/wt)
4
3
Mixing line between
Reach 1 input and VR-16
(B)
2
Mixing line between
km 60 and VFN
(61.3, 2.6)
3
2
Mixing line between
km 56 and C
1
1
Mixing line between km 56
and Return flow composition
0
0
5
10
15
20
25
30
35
40
Cl (mg/l)
Figure 22: Mixing diagrams for Verde River reaches 1 (A) and 2 (B) (June 2007 data),
plotted along with groundwater medians. Potential mixing lines between end members
are shown with 10% increments (crosses). Mixing lines are unique to each reach; end
members are chosen based on PCA.
78
(0.11, 4.9)
(17.0, 3.2)
(61.3, 2.6)
2.0
VR: Reach 3
VR Reach 2 input
Oak Creek input
Winter precipitation
Alluvium
BH
VFN
VFS
C
R-M
SO4/Cl ratio (wt/wt)
1.5
1.0
(C)
Mixing line between R2
input and OC input
0.5
0.0
0
5
10
15
20
25
30
35
40
Cl (mg/l)
5
(D)
SO4/Cl ratio (wt/wt)
4
Mixing line between R3
input and VFS maximum
3
VR: Reach 4
VR Reach 3 input
Winter precipitation
Alluvium
BH
VFN
VFS
VFS max
C
R-M
2
Mixing line between R3
input and VFS median
1
0
0
25
50
75
100
125
150
175
200
Cl (mg/l)
Figure 22 (continued): Mixing diagrams for Verde River reaches 3 (C) and 4 (D).
79
4.6 cfs (range: 0.3 cfs to 2.5 cfs). This amounts to approximately 10% of the final flow
reading.
Mixing analysis for reach 2 indicates three distinct chemical changes, for which
we further divide this reach (Figure 22B). In both summer and winter datasets, the
SO4/Cl ratios increase near km 61, before decreasing (see Figure 17). The first section
(km 66 to km 61) appears to be influenced by water with a high sulfate content. As
discussed in the PCA analysis the chemical signature of Black Hills spring water
represents a possible solution for this; however, the water present in the reach at its
lowest flow (sample VR-16) has a chemical composition that provides a better upper
bound to this subreach data. Using a mixing line between the final reach 1 chemical
composition and sample VR-16, input of the latter results in an input of 18% of the
subreach’s final flow, or 2.4% of the entire reach’s final flow. This amount translates to
an input of 1.2 cfs. Therefore while the solute input of this source is significant, the
actual flux of water is relatively small.
Downstream of kilometer 61, the apparent source of base flow is VFN
groundwater until kilometer 57, where it becomes return flows or possibly C groundwater
for the remainder of the reach. A mixing line between VR-21 (the sample at km 60) and
VFN groundwater yields an influx of 40% along the km 61 to km 57 subreach (5.5 cfs),
which translates to 12% of the reach’s final flow. This input represents a more
significant source of base flow than the initial high-sulfate input.
The third shift is a marked geochemical transition over a reach where flows
increase by 28 cfs, from 20.2 cfs at km 56 to 48.2 cfs just above the Oak Creek
80
confluence. As both C-aquifer groundwater and return flows are capable of explaining
the observed geochemical change in the Verde River (see Figure 22B) one approach is to
consider each source independently. The mixing line between VR-29 (the sample at km
56) and return-flow water results in a 60% return flow input for the downstream end of
this subreach. This translates to 28.9 cfs of return flows, which is similar but ~3% higher
than the observed increase of 28 cfs. The mixing line between VR-29 and C-aquifer
water would require a 31% input of C-aquifer water in the final reach flow, or 14.9 cfs.
This is considerably less than the observed increase of 28 cfs and would indicate that
while some C-aquifer type water may contribute to Verde River flow, the dominant
source along this reach is return flows. In this subreach two surface return flows were
noted and measured by the USGS (total 4.0 cfs) thus while these return flows are an
important source the majority must occur as shallow groundwater discharge to the river.
One way to estimate the potential contribution of each water source is to
determine a “hypothetical mixed” end member that would result in the observed
downstream geochemical composition when 28 cfs (58%) are added to the upstream flow
(VR-29). This mixed end member has a composition of 97% return flows and 3% Caquifer, translating to 27.2 cfs from return flows and 0.8 cfs from the C aquifer,
combining to equal the observed 28 cfs increase. One concern is the hydrogeologic
connection with the C aquifer in this region of the basin given this location’s distance
from where this aquifer is found. One potential explanation is that recharge occurs from
Oak Creek, which has a geochemical composition similar to the C-aquifer water (see
81
Figure 21A), into the Verde Formation which then transmits this water into the lower
portion of reach 2.
Verde River: Reach 3
Reach 3 is initially supplied with Oak Creek water, and becomes more like
alluvial aquifer groundwater downstream where flow is diverted (Figure 22C). Based on
a mixing line between reach 2 input and Oak Creek in the SO4/Cl versus Cl diagram, the
relative proportion of Oak Creek water immediately downstream of the confluence is
44%. Of the Verde River flow at this point (70 cfs) this translates to an Oak Creek input
of 30.8 cfs, which compares well with the actual observed Oak Creek discharge (Q = 29.8
cfs).
Downstream of the Oak Creek confluence, reach 3 flow alternates between losing
and gaining, with the three significant losses corresponding to ditch diversions. The two
gains in the reach are likely a result of groundwater fluxes from the alluvial aquifer. In
the first gaining reach Oak Creek flow increases by 32.4 cfs; this increase is accompanied
by a continued geochemical shift toward the Oak Creek composition. This indicates a
possible influx of groundwater that originated as Oak Creek water. In the second gaining
reach, where flow increases to 10.7 cfs from a minimum discharge of 0.5 cfs, the
geochemical shift is toward water with a signature like that of the alluvium or reach 2
input. This shift indicates that alluvial water may help sustain the base flow of the river
as agricultural diversions remove nearly all of the river’s water at the downstream end of
reach 3 (see Figure 9).
82
Verde River: Reach 4
This reach has an overall gain of 39.9 cfs over the length for which samples were
available (to km 5; see Figure 9) Given the lack of water present in Wet Beaver and
West Clear Creeks at the time of sampling, groundwater influx must occur (this was
supported by the observation of several springs along the reach). Based on the PCA
results the VFS subaquifer, a higher-TDS groundwater, is the likely end member for the
general increase in solutes we observe in reach 4. However, the curvature of reach 4
summer data points in the SO4/Cl versus Cl mixing diagram suggests that the median
composition of the sampled VFS groundwater is too dilute to explain the mixture of river
water observed (Figure 22D).
An end member which fits the mixing trend more closely is the maximum VFS
groundwater composition (data from Blasch et al., 2006). The use of this value as a
reasonable representation of VFS groundwater is based on the assumption that the 10
groundwater samples gathered from the VFS within the scope of this study may not
capture the full range of chemical compositions that result from the heterogeneity of the
Verde Formation. The heterogeneous distribution of evaporites within the southern part
of the formation makes this assumption rational. Using reach 3 input and this maximum
VFS value as end members, base flow is supported by 16.2 cfs of VFS groundwater (31%
of flow). The remainder of the flow increase (23.7 cfs) is perhaps explainable by baseflow input from incidental recharge that has retained a geochemical composition similar
to that of the reach’s water.
83
A losing section occurs at the downstream-most portion of reach 4 between km 5
(Q = 52.4) and USGS gage 09506000 (Q = 31.0 cfs) even though there are no river
diversions. This could reflect evaporation, or infiltration of Verde River water to the
VFS subaquifer. Since no river samples were obtained from this section of river, further
sampling is needed in order to more accurately describe the final decrease in flow.
Regardless of this, the relatively low residence times for groundwater in the Camp Verde
area support the concept of river-water infiltration occurring.
Conceptual Model
The geochemical results described above provide the critical constraints for a
conceptual model of the groundwater sources and groundwater-surface water interactions
in the middle Verde River watershed (Figure 23). Combining the geochemical results
with the June 2007 discharge measurements we have calculated the portions of base flow
contributed by various sources, and can thus describe the important hydrologic fluxes
into the Verde River.
The overall hydrogeologic framework involves recharge occurring primarily at
the higher elevations of the Colorado Plateau, adding water to Plateau aquifers which
eventually travels down-gradient to the Verde Formation aquifer in the valley. The
finding that high-elevation winter precipitation is the dominant source of recharge to
groundwater within the middle Verde River watershed is consistent with results
published by Blasch et al. (2006), which determined that natural recharge areas exist in
the Black Hills at elevations of 1870 to 2380 m and in the region above the Mogollon
84
N
Sycamore Creek
VF
N
VFN
(2%: 1.1 cfs)
Oak Creek
(30.8 cfs)
C/
RM
1
Page Springs (C)
(38%: 11.2 cfs)
Cottonwood
High SO4 source
(2.5%: 1.2 cfs)
VFN (12%: 5.5 cfs)
C (1.7%: 0.8 cfs)
2
e/
rg
ha
ec
l r r/ s
ra ate w
tu w flo
ul nd rn
ric ou tu
ag gr re
al al er
nt vi at
de lu -w
ci al ace
In
rf
su
56%: 27.2 cfs
R-M
(34%: 10.1 cfs)
Wet Beaver Creek
(0 cfs June 2007)
3
Montezuma’s Well (R-M)
(2.0 cfs)
42.6 cfs
46%: 23.7 cfs
Camp Verde
4
VFS (31%: 16.2 cfs)
S
VF
West Clear Creek
(0 cfs June 2007)
Verde River
infiltration
Figure 23: Conceptual model describing the hydrogeological framework of the middle
Verde River watershed. Base-flow inputs to the Verde River are calculated on the reach
scale, with arrows intended to represent inputs in general, not exact locations of such
inputs (e.g., western versus eastern bank of river). Schematic aquifer boundaries shown.
85
Rim at elevations of 2170 to 3920 m. This recharge infiltrates into the C and R-M
aquifers, which provide base flow to Sycamore, Oak, Wet Beaver, and West Clear
Creeks. The C and R-M aquifers also provide groundwater to the northern part of the
Verde Formation, via the regional groundwater flow path which is facilitated locally by
northwest—southeast faulting (e.g., the Page Springs Fault). In the southern part of the
valley, this groundwater mixing is negligible if existent. Groundwater in the southern
Verde Formation has a distinct composition suggestive of infiltration of Verde River
water and dissolution of local evaporites in the subsurface.
Within the study area the Verde River obtains base flow from multiple sources.
As it flows from the upper watershed into the middle watershed, it gains additional flow
from Sycamore Creek and, to a lesser extent, the northern part of the Verde Formation.
Between Clarkdale and the Oak Creek confluence, the Verde River gains an increasing
amount of base flow from the Verde Formation, as well as a minor but geochemically
distinct source of high-sulfate water in the first few kilometers of this gaining reach.
Return flows, incidental recharge to the alluvial aquifer, and possibly groundwater from
the C aquifer also contribute water to this reach. Oak Creek, as the largest tributary in the
watershed, is a major source of additional water to the Verde River, and the alluvial
aquifer seems to augment base flow when river flows are low due to ditch diversions.
South of I-17, where the Verde River enters the southern part of the Verde
Formation, groundwater inflow augments the river’s flow. This finding is consistent with
seepage investigation results for this reach described by Owen-Joyce and Bell (1983).
Specifically, this groundwater inflow is provided by the VFS subaquifer, a portion of
86
which is likely attributable to incidental recharge from agricultural water use. Though
the river gains water over the majority of this reach, a losing section occurs at the
downstream end of the reach, which may indicate water recharged from the river into the
VFS subaquifer. The geochemical results (radioactive and stable isotopic analyses of
VFS groundwater) corroborate this.
Discussion of Incidental Recharge/Surface-Water Returns
The results of the SO4/Cl versus Cl mixing analyses suggest that the amount of
incidental agricultural recharge/alluvial returns/surface-water return flows needed to
explain gains in flow over reaches 2 to 4 of the Verde River is 93.5 cfs. Though the
actual diversion amounts are largely unmonitored, an examination of the June 2007
discharge data yields an approximation of the amount of water diverted. Based on the
differences in flow measurements above and below identified ditches, the amount of
water diverted is approximately 194 cfs. Noting that not all surface-water return flows
were measured, the discharge data record a minimum of 30.5 cfs is returned to the Verde
River as surface-water return flows (5.4 cfs occurring in reach 2 and 25.1 cfs occurring in
reach 4). Furthermore, agricultural ET for the 10.5 km2 (2,600 acres) of irrigated land is
estimated to be 8,850 ac-ft/yr (S. Tadayon, USGS, personal commun., 2008), which with
an 8-month growing season equates to a consumptive use rate of 18.4 cfs. This leaves
approximately 145 cfs of potential incidental recharge, approximately 1.6 times the
amount of alluvial groundwater discharge quantified in the mixing analysis presented
here.
87
In addition to the potential error in the numbers presented above there are several
possible explanations for this: 1) a significant percentage of incidental recharge
associated with diversion recharges the Verde aquifer rather than discharging back to the
river; 2) during June diversions are highest thus, on an annual basis, incidental recharge
would be lower than estimated and 3) the alluvial groundwater system damps response,
thus while incidental recharge might be greatest during the summer months, alluvial
discharge is nearly constant year-round.
Implications for Water Resources Management
The results of this study have several implications for water resources
management both within the middle Verde River watershed as well as more broadly in
other semiarid river basins. One of these implications is that in contrast to typical
conceptual models of perennial rivers, groundwater-surface water exchanges are
complex, exhibiting significant fluxes in both directions that can change on a relatively
small scale. Over the 85-kilometer length of the middle Verde River studied here, baseflow sources vary on a several-kilometer scale. Two gaining reaches without significant
tributary input exhibit base-flow increases which can be explained by a complex
combination of sources including a hydrologic connection to the regional aquifer and
discharge of alluvial groundwater derived from incidental recharge of agricultural
diversions. Elsewhere recharge of surface water to the underlying aquifer was observed,
in the case of the downstream-most reach supplying water to the VFS subaquifer. The
88
knowledge of such locations and amount of these exchanges is critical for the
development of proper water resources models.
Taken together the water exchanges detailed in this study—both between aquifers
and between surface water and groundwater—highlight the importance of geologic
structures in controlling aquifer connections and water flow paths. Consider for example
the contrast between the VFN—where there is some discharge of C and R-M aquifer
groundwater to regional springs and some transmission in the Verde Formation—and the
VFS where there is spring discharge but no geochemical evidence for significant
exchange with the VFS aquifer. Understanding these connections helps to assess the
potentially different impacts that groundwater pumping will have locally, depending on
the aquifer involved. For example, on the regional scale intensive groundwater
withdrawal in the C and R-M aquifers has the potential of decreasing groundwater flow
to the VFN subaquifer, and thus ultimately decreasing base flow to the Verde River and
its tributaries.
Consideration should be given additionally to the effects of surface-water
diversions as the results of this study demonstrate the importance of alluvial groundwater
returns in sustaining perennial flow. As seen in reach 2-4, the return of incidental
recharge from agricultural irrigation is a significant source of base flow. On the middle
Verde of 193 total cfs in surface flow increases the mixing model analysis presented here
attributes 93.5 cfs to alluvial groundwater discharge or surface-water return flows. This
is due largely to the significant amount of surface-water diversions; this incidental
recharge is substantial and provides an important reservoir for perennial base flow.
89
Seasonal flooding also provides a recharge to this alluvial aquifer and during
predevelopment was likely a significant source of recharge to the Verde Formation
aquifer in the southern portion of the study area.
Finally the approach of this study, combining both detailed river flow information
with geochemical data, provides a powerful tool for understanding both the dynamics of
groundwater-surface water exchange at the river basin scale and the water sources that
drive these exchanges. As such continued monitoring of both surface-water flows and
geochemical data will allow managers to assess not only how flow is changing, but what
specific sources may be responsible for an observed change. Such information will
enable a clearer assessment of the potential reasons for changes in flow and allow for
more effective action to be taken.
Study Limitations and Recommendations for Further Research
Many of these implications could be tested further by expanding the available
datasets both spatially and temporally. A limitation that arose due to time constraints and
the accessibility of wells is a low density of groundwater samples in several areas of
particular interest. Specifically, a greater density of groundwater samples could be
obtained to test (1) the role of the northwest-southeast trending faults in facilitating
groundwater flow from the C and R-M aquifers to the VFN subaquifer, (2) the
interactions between alluvial groundwater and Verde River stream flow, and (3) the
boundary between the VFN and VFS subaquifers. Concerning (2) in particular, the legal
90
issue of subflow (which was not an objective of this study) could be better addressed
through further research.
An additional limitation of this study is potential uncertainty in the mixing
analyses due to heterogeneity of base-flow end members. In this study, medians are used
as representative geochemical compositions for end members, though there may be a
better representation for groundwater from heterogeneous aquifers such as the VFS
subaquifer. This is exhibited in the mixing analysis for Verde River reach 4, where the
clear mixing curve that emerges is more accurately described by the maximum values for
the VFS groundwater composition than median values. A greater sampling density in the
VFS subaquifer could aid this issue.
91
CONCLUSIONS
As a result of the suite of analyses conducted in this study, we were able to
generate an improved conceptual model of the hydrogeologic conditions in the middle
Verde River watershed. Analysis of the stable isotopic, radioactive isotopic, and solute
signatures of groundwater sources enabled us to distinguish regional groundwater (C and
R-M) from local groundwater (the Verde Formation and alluvium), and describe the
interactions between them. Comparing these geochemical compositions to those
observed in the Verde River and its tributaries, we were able to describe the predominant
groundwater-surface water interactions in the watershed.
For identifying and quantifying these interactions, we found that the combined
use of PCA, solute mixing diagrams, and discharge data is an especially useful approach.
PCA effectively reveals base-flow end members, and the use of simple mixing diagrams
in geochemical space allows for the calculation of percentages of base-flow influxes.
These percentages can then be combined with comprehensive discharge data to translate
to actual groundwater fluxes. The application of this approach can be extended to other
regions of hydrogeologic complexity where changes in base-flow source may also occur
at the kilometer scale.
The results of this study additionally highlight the importance of both local and
regional groundwater in sustaining the base flow of a perennial stream system. As
growing population and persisting drought conditions continue to pressure water
resources in the middle Verde River watershed and elsewhere in the semiarid Southwest,
92
best management practices will arise from a consideration of the intricacies of these
groundwater-surface water interactions.
93
APPENDIX A1: Surface-Water Geochemical Results
(River km measured as km upstream from USGS gage 09506000; [--]=no data; nd=below detection limit)
Sample
Coordinate
Sample
River
Latitude/
Longitude/
temperSample ID
System/
Date
start
km
Northing
Easting
ature
Datum
time
(°C)
November-2006
Sycamore Creek
SC11180601
85.9 N34.8665
W112.06908
WGS84 11/18/2006 8:00
11.6
Verde River
VR11180601
81.9 N34.85171
W112.06511
WGS84 11/18/2006 9:00
11.5
VR11180602
68.4 N34.78715
W112.05153
WGS84 11/18/2006 9:45
11.0
VR11170605
65.8 N34.76724
W112.03957
WGS84 11/17/2006 17:40
12.8
VR11170601
61.4 N34.75043
W112.0222
WGS84 11/17/2006 7:30
7.0
VR11170604
55.5 N34.72267
W111.9911
WGS84 11/17/2006 17:20
12.6
VR11180603
48.3 N34.69035
W111.96583
WGS84 11/18/2006 10:40
11.2
VR11180604
43.7 N34.67415
W111.93835
WGS84 11/18/2006 11:15
11.3
VR11180605
32.0 N34.60947
W111.88644
WGS84 11/18/2006 11:45
11.9
VR11180607
24.7 N34.57338
W111.85751
WGS84 11/18/2006 17:42
13.1
VR11180606
20.9 N34.55047
W111.85137
WGS84 11/18/2006 17:15
13.0
VR11190601
13.3 N34.50608
W111.83709
WGS84 11/19/2006 10:50
12.0
Oak Creek
OC11170608 125.2 N35.02178
W111.73669
WGS84 11/17/2006 13:35
10.1
OC11170609 122.4 N34.99978
W111.73946
WGS84 11/17/2006 14:00
11.8
OC11170610 117.3 N34.96539
W111.75139
WGS84 11/17/2006 14:20
9.4
OC11170607 114.9 N34.94685
W111.75421
WGS84 11/17/2006 13:15
10.6
OC11170611 111.5 N34.92501
W111.73463
WGS84 11/17/2006 14:40
9.8
OC11170612 106.7 N34.88705
W111.73079
WGS84 11/17/2006 15:00
13.8
OC11170613 102.0 N34.86229
W111.76192
WGS84 11/17/2006 15:25
12.4
OC11170614
99.1 N34.8432
W111.77792
WGS84 11/17/2006 16:10
12.3
OC11170606
94.7 N34.82544
W111.80727
WGS84 11/17/2006 12:00
11.2
OC11170603
90.2 N34.8101
W111.82874
WGS84 11/17/2006 11:00
9.3
OC11170615
80.4 N34.79961
W111.8826
WGS84 11/17/2006 16:47
11.1
OC11170602
72.0 N34.7653
W111.89095
WGS84 11/17/2006 10:15
14.8
OC11170601
58.5 N34.71799
W111.91609
WGS84 11/17/2006 9:50
11.2
Wet Beaver Creek
WB11180601 60.8
---11/18/2006 14:30
-WB11180602 59.6 N34.67488
W111.67226
WGS84 11/18/2006 15:00
-WB11180603 55.0 N34.66877
W111.71412
WGS84 11/18/2006 16:15
13.1
WB11190606 50.1 N34.6481
W111.7515
WGS84 11/19/2006 9:55
12.6
WB11190604 47.1 N34.64087
W111.77906
WGS84 11/19/2006 9:05
10.3
WB11190602 33.3 N34.61122
W111.83976
WGS84 11/19/2006 8:20
7.8
WB11190601 26.1 N34.58677
W111.85482
WGS84 11/19/2006 8:00
7.9
Dry Beaver Creek
WB11190603 41.1 N34.63644
W111.81803
WGS84 11/19/2006 8:45
7.1
West Clear Creek
WC11180601 19.0 N34.51795
W111.77098
WGS84 11/18/2006 16:55
12.7
94
APPENDIX A1 – Continued
Sample ID
Sp.
δ18O δ2H
Cond. pH
(‰) (‰)
(uS/cm)
November-2006
Sycamore Creek
SC11180601
501
Verde River
VR11180601
499
VR11180602
492
VR11170605
500
VR11170601
477
VR11170604
562
VR11180603
558
VR11180604
489
VR11180605
489
VR11180607
544
VR11180606
552
VR11190601
634
Oak Creek
OC11170608
250
OC11170609
268
OC11170610
300
OC11170607
296
OC11170611
304
OC11170612
278
OC11170613
277
OC11170614
280
OC11170606
284
OC11170603
293
OC11170615
300
OC11170602
421
OC11170601
409
Wet Beaver Creek
WB11180601 231
WB11180602 236
WB11180603 257
WB11190606 455
WB11190604 493
WB11190602 514
WB11190601 488
Dry Beaver Creek
WB11190603 541
West Clear Creek
WC11180601 365
Alkalinity
NO3
SO4
NO2
(mg/L
Br
Cl
F
ANC as (mg/L) (mg/L) (mg/L) (mg/L) (mg/L) (mg/L)
CaCO3)
8.0 -11.4 -81.7
293
0.12
5.8
nd
0.03
0.27
4.4
8.0
8.2
8.0
8.0
8.1
8.1
8.2
8.2
8.1
8.1
8.1
-10.8
-10.7
-10.7
-10.5
-10.4
-10.4
-10.9
-10.8
-10.8
-10.7
-10.6
-78.5
-78.3
-77.6
-76.4
-75.6
-75.0
-77.9
-76.9
-76.8
-76.2
-76.3
271
266
255
269
281
279
259
240
267
270
284
0.20
0.20
0.21
0.25
0.21
0.22
0.17
0.17
0.19
0.22
0.24
13.8
13.8
14.4
15.8
17.6
17.2
15.2
15.4
18.2
19.2
24.3
nd
nd
nd
0.06
nd
0.03
nd
nd
nd
nd
nd
0.07
0.08
0.08
0.08
0.09
0.10
0.11
0.06
0.06
0.08
0.07
0.58
0.13
0.06
0.01
0.05
0.02
nd
nd
0.27
0.20
0.36
8.3
8.2
18.2
30.5
31.6
29.4
17.5
19.8
34.4
36.1
61.3
7.9
7.9
8.1
8.2
8.3
7.9
8.1
7.6
7.9
8.1
8.0
7.7
8.0
-11.8
-11.8
-11.7
-11.7
-11.7
-11.8
-11.7
-11.8
-11.7
-11.6
-11.6
-11.5
-11.5
-82.6
-82.9
-83.0
-81.6
-82.2
-82.8
-82.4
-81.4
-81.2
-82.0
-80.0
-80.5
-79.4
145
156
176
178
180
162
162
710
172
172
172
219
224
0.05
0.06
0.07
0.08
0.06
0.07
0.08
0.07
0.07
0.10
0.07
0.10
0.11
1.9
1.9
2.3
2.4
2.3
3.2
3.4
3.3
3.3
3.6
3.5
16.5
12.7
0.01
nd
nd
nd
nd
nd
nd
nd
nd
0.02
nd
nd
nd
0.01
0.02
0.01
0.01
0.01
0.01
0.01
0.01
0.01
0.01
0.01
0.05
0.03
1.17
0.10
0.08
0.02
nd
0.15
0.07
0.01
nd
nd
nd
0.52
0.54
0.7
1.0
1.1
1.4
1.2
1.4
1.4
1.4
1.4
1.4
1.4
3.7
3.5
7.5
7.8
7.7
7.6
8.1
8.1
8.0
-11.2
-11.2
-11.1
-11.0
-11.0
-10.4
-10.7
-79.3
-79.0
-78.8
-78.8
-79.0
-76.4
-77.2
127
132
144
265
281
282
250
0.08
0.09
0.10
0.12
0.13
0.13
0.17
3.2
3.2
3.2
11.3
14.3
16.6
15.4
0.00
nd
0.00
nd
nd
nd
nd
0.01
0.01
0.01
0.03
0.04
0.05
0.06
0.32
0.25
0.01
0.04
0.01
nd
nd
1.4
1.5
1.4
3.4
4.5
4.8
17.7
8.1 -10.4 -76.1
295
0.12
18.7
nd
0.05
nd
5.1
8.2 -10.8 -76.5
221
0.08
3.9
nd
0.02
nd
2.2
95
APPENDIX A1 – Continued
Sample ID
As
B
Ba
Ca
Mg
Na
Si
Sr
K
(mg/L) (mg/L) (mg/L) (mg/L) (mg/L) (mg/L) (mg/L) (mg/L) (mg/L)
November-2006
Sycamore Creek
SC11180601
0.01
Verde River
VR11180601
0.02
VR11180602
0.02
VR11170605
0.02
VR11170601
0.02
VR11170604
0.02
VR11180603
0.01
VR11180604
0.02
VR11180605
0.01
VR11180607
0.02
VR11180606
0.02
VR11190601
0.01
Oak Creek
OC11170608
0.00
OC11170609
0.01
OC11170610
0.00
OC11170607
0.01
OC11170611
0.00
OC11170612
0.01
OC11170613
0.01
OC11170614
0.01
OC11170606
0.00
OC11170603
0.01
OC11170615
0.01
OC11170602
0.01
OC11170601
0.02
Wet Beaver Creek
WB11180601
0.01
WB11180602
0.01
WB11180603
0.01
WB11190606
0.03
WB11190604
0.02
WB11190602
0.02
WB11190601
0.01
Dry Beaver Creek
WB11190603
0.01
West Clear Creek
WC11180601
0.00
0.08
0.19
25.0
1.6
32.9
5.3
7.8
0.14
0.18
0.17
0.17
0.16
0.17
0.17
0.17
0.12
0.14
0.15
0.18
0.15
0.14
0.13
0.17
0.12
0.13
0.16
0.18
0.12
0.16
0.12
21.3
21.2
23.6
39.5
27.7
29.0
29.4
46.7
25.2
61.2
25.2
2.1
2.2
2.2
2.4
2.5
2.4
2.4
2.0
2.4
2.4
2.5
25.9
26.1
27.8
32.4
34.5
33.1
32.4
29.3
32.5
33.5
39.2
27.0
27.6
27.6
28.1
30.1
29.3
22.4
22.1
30.0
31.2
40.3
9.9
9.5
9.5
9.6
10.5
10.1
9.6
8.7
10.4
11.8
13.1
0.20
0.23
0.23
0.24
0.25
0.25
0.23
0.26
0.37
0.51
0.59
0.01
0.03
0.02
0.02
0.01
0.01
0.02
0.04
0.02
0.04
0.07
0.06
0.06
0.12
0.29
0.28
0.33
0.24
0.23
0.37
0.26
0.21
0.37
0.19
0.16
0.16
34.9
37.0
39.7
42.2
45.6
37.2
38.2
38.9
38.4
40.8
40.3
52.8
41.1
0.7
1.0
0.8
0.9
1.0
1.0
1.1
1.2
1.0
1.4
1.4
1.7
1.6
15.9
17.4
18.9
20.2
20.0
17.9
18.1
22.2
18.6
19.4
19.5
22.7
23.5
2.7
4.2
2.7
3.3
3.6
4.3
5.0
5.8
4.7
6.3
6.1
13.2
12.0
6.4
6.7
5.9
6.1
6.0
7.4
7.3
8.7
7.3
7.4
7.2
7.1
7.5
0.11
0.13
0.08
0.12
0.11
0.13
0.14
0.14
0.13
0.13
0.14
0.21
0.18
0.02
0.05
0.02
0.18
0.25
0.27
0.12
0.29
0.31
0.31
0.23
0.22
0.21
0.16
28.8
27.1
29.8
47.5
39.0
22.2
58.6
1.9
1.7
1.4
2.6
2.6
2.8
2.3
14.9
16.1
17.8
26.1
27.3
30.2
30.2
6.9
7.1
6.3
19.2
22.7
25.2
21.9
9.6
9.7
10.1
10.5
10.0
9.9
8.6
0.18
0.16
0.18
0.22
0.24
0.25
0.26
0.28
0.12
20.4
2.7
30.2
25.2
10.0
0.24
0.02
0.16
46.8
1.5
26.0
6.4
8.4
0.19
96
APPENDIX A1 – Continued
Sample ID
June-2007
Verde River
VR-01
VR-02
VR-03
VR-04
VR-05
VR-06
VR-07
VR-08
VR-09
VR-10
VR-13
VR-15
VR-16
VR-17
VR-18
VR-19
VR-20
VR-21
VR-23
VR-24
VR-28
VR-29
VR-31A
VR-31B
VR-32
VR-36
VR-37
VR-38
VR-39
VR-41
VR-42
VR-43
VR-44
VR-45
VR-46
VR-47
VR-49
VR-50
VR-51
VR-52
VR-54
River
km
82.2
81.9
79.2
75.0
73.3
68.7
68.5
66.3
66.2
66.1
65.6
64.9
64.4
64.4
63.2
62.5
61.2
60.6
60.4
60.4
57.9
57.4
55.9
55.9
55.5
51.1
48.6
48.0
44.7
44.3
43.2
43.0
40.0
38.2
36.0
34.4
31.0
30.0
28.6
27.2
26.1
Latitude/
Northing
Longitude/
Easting
N34 51 06
W112 03 55
N34 50 58.43 W112 03 46.62
N34 50 04.03 W112 02 53.62
N34 48 42.13 W112 03 28.42
N34 48 07.33 W112 02 43.63
N34 47 42.15 W112 03 31.42
N34 47 06.51 W112 02 59.63
N34 46 39.52 W112 02 56.15
N34 46 36.985 W112 02 46.01
N34 46 07.84 W112 02 11.95
N34 45 53.3 W112 02 01.0
N34 45 58.3 W112 01 35.5
N34 45 57.6 W112 01 18.2
N34 45 56.1 W112 01 17.3
N34 45 27.9 W112 01 42.3
N34 45 16.0 W112 01 38.8
N34 45 03.54 W112 01 00.45
N34 45 04.74 W112 00 39.45
N34 44 58.0 W112 00 32.8
N34 44 57.7 W112 00 30.9
N34 44 20
W111 59 55
N34 44 03.7 W112 00 00.3
N34 43 26.7 W111 59 28.7
N34 43 26.7 W111 59 28.7
N34 43 13.0 W111 59 23.4
N34 41 57.94 W111 57 39.75
N34 41 25.34 W111 57 54.36
N34 41 05.64 W111 57 47.96
N34 40 43.83 W111 56 31.86
N34 40 32.43 W111 56 23.46
N34 39 59.53 W111 56 13.96
N34 39 56
W111 56 11
N34 38 25.93 W111 55 46.86
N34 37 51.07 W111 54 57.0
N34 37 57.49 W111 54 13.67
N34 37 03.5 W111 53 57.8
N34 36 29.3 W111 52 35.0
N34 35 58.1 W111 52 40.3
N34 35 18.9 W111 52 55.4
N34 34 55.2 W111 52 16.9
N34 34 30.7 W111 51 57.3
Coordinate
System/
Datum
Date
NAD27
NAD27
NAD27
NAD27
NAD27
NAD27
NAD27
NAD27
NAD27
NAD27
NAD27
NAD27
NAD27
NAD27
NAD27
NAD27
NAD27
NAD27
NAD27
NAD27
NAD27
NAD27
NAD27
NAD27
NAD27
NAD27
NAD27
NAD27
NAD27
NAD27
NAD27
NAD27
NAD27
NAD27
NAD27
NAD27
NAD27
NAD27
NAD27
NAD27
NAD27
6/20/2007
6/20/2007
6/20/2007
6/20/2007
6/20/2007
6/20/2007
6/20/2007
6/20/2007
6/20/2007
6/20/2007
6/20/2007
6/20/2007
6/20/2007
6/20/2007
6/20/2007
6/20/2007
6/20/2007
6/20/2007
6/20/2007
6/20/2007
6/20/2007
6/20/2007
6/20/2007
6/20/2007
6/20/2007
6/21/2007
6/21/2007
6/21/2007
6/21/2007
6/21/2007
6/21/2007
6/21/2007
6/21/2007
6/21/2007
6/21/2007
6/21/2007
6/21/2007
6/21/2007
6/21/2007
6/21/2007
6/21/2007
Sample
Sample
temperstart
ature,
time
(°C)
9:30
11:00
13:25
16:00
15:45
9:10
12:40
13:40
15:14
9:20
16:00
9:45
----11:06
13:10
11:30
12:00
17:15
9:30
14:15
17:05
16:10
14:30
9:30
10:50
13:00
15:45
16:50
10:35
11:08
14:30
17:00
----10:30
12:15
20.7
21.4
25.1
26.6
26.7
22.6
25.4
24.2
25.4
22.5
-25.5
29.5
20.9
28.6
28.2
22.6
24.9
23.4
23.5
-20.0
25.9
-26.2
27.4
23.2
23.3
25.9
27.3
27.1
24.9
26.0
27.7
27.0
24.5
27.5
28.2
26.6
23.6
26.2
97
APPENDIX A1 – Continued
Sample ID
June-2007
Verde River
VR-01
VR-02
VR-03
VR-04
VR-05
VR-06
VR-07
VR-08
VR-09
VR-10
VR-13
VR-15
VR-16
VR-17
VR-18
VR-19
VR-20
VR-21
VR-23
VR-24
VR-28
VR-29
VR-31A
VR-31B
VR-32
VR-36
VR-37
VR-38
VR-39
VR-41
VR-42
VR-43
VR-44
VR-45
VR-46
VR-47
VR-49
VR-50
VR-51
VR-52
VR-54
Sp.
δ18O δ2H
Cond. pH
(‰) (‰)
(uS/cm)
522
520
506
487
484
495
490
490
490
494
-550
1074
552
598
621
685
681
664
673
-668
633
-626
623
593
597
592
528
531
-506
--530
580
534
568
685
756
7.8
7.3
7.6
7.2
7.3
7.7
7.6
7.5
7.4
7.7
7.9
7.7
7.9
7.7
7.9
8.0
7.7
7.9
7.9
8.1
8.0
8.1
7.9
7.8
8.0
8.1
7.7
7.7
7.9
7.7
7.9
7.7
7.8
7.7
7.6
7.8
7.5
8.0
7.8
7.6
7.9
-10.8
-11.1
-10.9
-10.8
-10.8
-10.8
-10.8
-10.7
-10.6
-10.6
--10.5
-9.6
-9.4
-9.4
-9.5
-9.5
-9.6
-9.7
-9.7
--10.0
-10.2
-10.2
-10.1
-10.2
-10.3
-10.2
-10.2
-10.5
-10.5
-10.6
-10.6
-10.6
-10.5
-10.4
-10.0
-10.3
-10.2
-10.2
-10.2
-77.8
-77.5
-77.9
-77.1
-77.3
-77.6
-76.5
-77.9
-77.6
-77.6
--77.6
-73.6
-73.2
-73.7
-73.5
-73.2
-73.3
-73.3
-74.0
--73.7
-74.4
-74.6
-75.0
-75.2
-75.0
-75.9
-75.6
-76.8
-77.2
-77.5
-77.3
-76.8
-77.3
-77.0
-74.9
-76.8
-76.7
-75.7
-75.4
Alkalinity
NO3
SO4
NO2
Br
(mg/L
Cl
F
ANC as (mg/L) (mg/L) (mg/L) (mg/L) (mg/L) (mg/L)
CaCO3)
258
332
235
214
228
224
218
234
216
234
277
234
295
294
269
270
289
282
254
273
280
297
287
281
282
275
267
312
266
241
244
246
237
235
231
245
266
244
253
268
275
0.24
0.28
0.23
0.24
0.24
0.22
0.23
0.23
0.24
0.24
-0.25
0.32
0.25
0.27
0.28
0.27
0.27
0.27
0.24
-0.28
0.27
0.27
0.27
0.26
0.26
0.26
0.26
0.21
0.21
0.20
0.20
0.21
0.21
0.21
0.25
0.22
0.25
0.25
0.28
13.2
13.1
13.2
13.4
13.3
13.1
13.3
13.3
13.5
13.8
-14.4
20.9
14.7
15.9
16.4
16.4
16.6
20.2
20.5
-21.7
20.1
19.7
19.4
18.7
17.3
17.5
17.6
16.6
16.4
16.4
16.3
16.4
16.6
16.8
19.3
17.6
18.9
21.7
29.0
nd
nd
nd
0.01
nd
nd
nd
nd
nd
nd
-0.00
nd
nd
nd
nd
nd
nd
nd
nd
-nd
nd
nd
0.01
nd
nd
nd
nd
nd
nd
nd
nd
nd
nd
nd
nd
nd
nd
nd
nd
0.08
0.08
0.08
0.09
0.09
0.09
0.09
0.09
0.09
0.09
-0.09
0.14
0.10
0.10
0.10
0.10
0.10
0.12
0.12
-0.12
0.14
0.11
0.11
0.11
0.10
0.10
0.11
0.08
0.08
0.08
0.07
0.07
0.07
0.08
0.09
0.09
0.08
0.09
0.10
0.47
0.43
0.27
0.08
0.06
0.02
0.01
0.02
0.02
0.01
-0.09
0.02
0.03
nd
0.02
0.01
nd
0.40
0.46
-0.07
0.38
0.36
0.34
0.13
0.10
0.09
0.05
0.03
0.02
0.02
0.01
0.01
0.01
0.01
0.01
0.02
0.13
nd
0.04
7.5
7.4
7.4
7.5
7.5
7.3
7.3
7.3
8.0
12.6
-32.7
277.4
8.8
37.5
48.0
57.2
59.5
53.4
47.6
-42.0
36.2
35.4
34.5
32.1
29.0
29.3
29.8
18.6
18.9
17.1
16.7
16.8
18.3
20.5
24.6
22.6
30.5
49.8
92.8
98
APPENDIX A1 – Continued
Sample ID
June-2007
Verde River
VR-01
VR-02
VR-03
VR-04
VR-05
VR-06
VR-07
VR-08
VR-09
VR-10
VR-13
VR-15
VR-16
VR-17
VR-18
VR-19
VR-20
VR-21
VR-23
VR-24
VR-28
VR-29
VR-31A
VR-31B
VR-32
VR-36
VR-37
VR-38
VR-39
VR-41
VR-42
VR-43
VR-44
VR-45
VR-46
VR-47
VR-49
VR-50
VR-51
VR-52
VR-54
As
B
Ba
Ca
Mg
Na
Si
Sr
K
(mg/L) (mg/L) (mg/L) (mg/L) (mg/L) (mg/L) (mg/L) (mg/L) (mg/L)
0.02
0.02
0.02
0.02
0.02
0.02
-0.02
0.02
0.02
0.02
-0.01
0.02
0.02
0.02
0.01
0.01
0.01
0.01
0.01
0.01
0.01
0.01
0.02
0.02
0.02
0.02
0.02
-0.02
0.02
0.02
0.02
0.02
0.02
0.02
0.02
0.02
0.02
0.02
0.19
0.18
0.18
0.20
0.20
0.20
-0.19
0.19
0.19
0.19
-0.23
0.21
0.21
0.22
0.21
0.21
0.18
0.21
0.21
0.19
0.19
0.21
0.23
0.18
0.20
0.21
0.18
-0.15
0.17
0.15
0.15
0.15
0.16
0.18
0.14
0.20
0.20
0.23
0.14
0.15
0.17
0.14
0.13
0.13
-0.13
0.13
0.13
0.15
-0.10
0.18
0.18
0.14
0.11
0.12
0.15
0.11
0.10
0.14
0.15
0.13
0.15
0.15
0.13
0.12
0.15
-0.10
0.11
0.12
0.11
0.11
0.12
0.09
0.13
0.12
0.10
0.10
18.9
23.7
44.8
26.8
23.4
20.4
-21.4
23.0
23.6
56.4
-52.8
41.6
54.6
34.7
28.8
32.4
62.2
34.6
23.0
57.1
62.1
51.6
59.6
58.6
39.8
35.0
56.7
-27.1
26.9
31.2
23.8
28.1
38.7
27.1
52.3
42.8
37.3
45.5
2.3
2.4
2.2
2.5
2.5
2.5
-2.5
2.5
2.5
2.4
-3.3
1.2
1.5
1.8
2.1
2.0
1.9
2.2
2.4
2.2
2.4
2.5
2.7
2.4
2.7
2.7
2.7
-2.4
2.5
2.3
2.3
2.3
2.3
2.8
2.2
2.5
2.6
2.9
25.6
25.3
25.8
25.6
25.4
26.0
-25.6
25.9
26.7
34.0
-97.5
32.3
38.0
42.4
41.0
40.5
41.2
37.5
38.7
40.2
38.6
36.4
37.0
35.4
33.0
33.2
36.0
-30.1
29.3
30.0
29.7
30.5
30.3
34.3
32.1
34.1
36.3
41.6
24.4
26.6
24.9
25.9
27.6
25.3
-25.7
26.0
26.1
29.3
-36.7
29.8
28.8
29.1
31.8
30.4
29.9
30.4
30.4
32.5
30.7
30.9
30.2
30.2
29.9
29.9
30.3
-24.6
22.3
22.0
22.2
23.0
23.5
27.7
24.4
27.0
33.9
57.5
9.7
9.6
9.8
9.8
9.9
9.8
-9.5
9.6
9.5
11.1
-9.8
9.8
8.8
9.6
9.2
9.1
9.7
9.6
11.1
11.7
12.0
11.5
11.9
11.3
10.7
10.7
11.5
-9.9
9.5
10.2
10.1
10.1
9.9
10.7
10.3
11.0
11.0
11.9
0.16
0.17
0.22
0.17
0.17
0.16
-0.16
0.18
0.17
0.28
-0.27
0.21
0.26
0.22
0.22
0.21
0.29
0.23
0.24
0.32
0.31
0.26
0.30
0.29
0.23
0.22
0.28
-0.19
0.19
0.20
0.19
0.19
0.22
0.42
0.36
0.40
0.47
0.61
99
APPENDIX A1 – Continued
Sample ID
River
km
Latitude/
Northing
June-2007 (cont'd)
Verde River (cont'd)
VR-55
25.6 N34 34 27.0
VR-56
25.2 N34 34 24.5
VR-57
25.1 N34 34 25.2
VR-61A
21.4 N34 32 54.2
VR-61B
--VR-62
18.8 N34 31 55.7
VR-63
15.4 N34 31 29.4
VR-63I
15.3 N34 31 11.6
VR-65
13.1 N34 30 21.18
VR-66
11.0 N34 29 52.62
VR-67
8.6 N34 28 46.79
VR-68
5.4 N34 28 05.01
Verde River Diversions
VR-11
65.6 N34 45 50
VR-59
22.3 N34 33 18.52
Verde River Return Flows
VR-22
60.9 N34 45 05.44
VR-26
59.6 N34 45 03.8
VR-30
57.2 N34 43 56.7
VR-33
54.0 N34 42 32
VR-60
21.7 N34 32 59.42
Oak Creek
T-11
99.5 N34 50 40
T-10
98.5 N34 50 23.0
T-9
95.5 N34 49 25.9
T-7B
89.0 N34 49 00.3
T-6
80.9 N34 48 04
T-5
70.9 N34 45 22
T-4C
67.0 N34 44 41
VR-40
44.6 N34 40 43.22
Wet Beaver Creek
T-7A
55.3 N34 40 05
T-4B
46.5 N34 38 14.63
unknownN34 36 32.6
T-3
West Clear Creek
T-4A
20.6 N34 30 52.1
T-2
15.6 N34 31 21.6
T-1
13.3 N34 30 40.3
Sample
Sample
temperstart
ature,
time
(°C)
Longitude/
Easting
Coordinate
System/
Datum
Date
W111 51 38.2
W111 51 18.2
W111 51 12.0
W111 51 11.0
-W111 52 06.2
W111 50 04.7
W111 50 03.8
W111 50 09.50
W111 48 55.40
W111 48 47.42
W111 47 59.68
NAD27
NAD27
NAD27
NAD27
-NAD27
NAD27
NAD27
NAD27
NAD27
NAD27
NAD27
6/21/2007
6/21/2007
6/21/2007
6/21/2007
6/21/2007
6/21/2007
6/21/2007
6/21/2007
6/22/2007
6/22/2007
6/22/2007
6/22/2007
15:00
16:15
17:30
10:05
10:35
13:45
16:50
17:20
11:30
12:45
15:50
10:51
27.2
26.1
25.8
26.3
27.2
27.1
26.5
-22.6
24.9
26.1
24.2
W112 02 04
W111 50 51.47
NAD27
NAD27
6/20/2007
6/21/2007
12:30
18:10
25.6
24.9
W112 00 51.85
W112 00 03.8
W111 59 55.9
W111 59 04
W111 50 57.07
NAD27
NAD27
NAD27
NAD27
NAD27
6/20/2007
6/20/2007
6/20/2007
6/20/2007
6/21/2007
13:35
15:00
10:40
-16:55
26.9
25.9
23.7
-25.6
W111 46 36
W111 47 07.0
W111 48 05.9
W111 50 15.1
W111 52 48
W111 53 47
W111 53 44
W111 56 24.64
NAD27
NAD27
NAD27
NAD27
NAD27
NAD27
NAD27
NAD27
6/26/2007
6/26/2007
6/26/2007
6/26/2007
6/26/2007
6/26/2007
6/26/2007
6/21/2007
10:30
19:25
17:00
12:30
11:50
14:50
16:40
14:00
20.0
23.1
26.3
24.4
25.9
23.4
25.7
27.3
W111 42 49
W111 47 28.59
W111 47 06.99
NAD27
NAD27
NAD27
6/26/2007
6/26/2007
6/26/2007
16:45
13:15
12:00
24.2
27.3
26.5
W111 45 19.5
W111 48 16.3
W111 49 24.1
NAD27
NAD27
NAD27
6/26/2007
6/26/2007
6/26/2007
15:55
11:55
9:55
25.9
-22.6
100
APPENDIX A1 – Continued
Sample ID
Sp.
δ18O δ2H
Cond. pH
(‰) (‰)
(uS/cm)
June-2007 (cont'd)
Verde River (cont'd)
VR-55
758
7.8
VR-56
795
7.8
VR-57
815
8.0
VR-61A
773
8.0
VR-61B
840
8.0
VR-62
1060 8.1
VR-63
1274 8.1
VR-63I
-7.9
VR-65
1112 8.1
VR-66
1172 8.2
VR-67
1196 8.0
VR-68
1143 7.9
Verde River Diversions
VR-11
494
8.0
VR-59
785
8.1
Verde River Return Flows
VR-22
494
8.0
VR-26
488
7.5
VR-30
506
8.0
VR-33
583
7.7
VR-60
780
8.0
Oak Creek
T-11
302
7.1
T-10
300
7.2
T-9
302
7.4
T-7B
319
7.3
T-6
321
7.8
T-5
427
7.2
T-4C
414
7.4
VR-40
445
7.6
Wet Beaver Creek
T-7A
269
7.1
T-4B
542
7.8
T-3
545
7.6
West Clear Creek
T-4A
350
7.9
T-2
385
7.8
T-1
628
7.7
-10.3
-10.3
-10.4
-10.3
--10.1
-10.1
--10.1
-10.1
-10.0
-9.9
Alkalinity
SO4
NO2
NO3
(mg/L
Cl
Br
F
ANC as (mg/L) (mg/L) (mg/L) (mg/L) (mg/L) (mg/L)
CaCO3)
-75.4
-76.5
-76.0
-77.4
--76.7
-73.9
--75.4
-75.5
-75.3
-75.5
262
290
304
295
294
318
328
272
325
319
315
309
0.32
0.39
0.38
0.40
-0.44
0.62
-0.52
0.49
0.47
0.44
28.7
31.5
30.0
31.0
-53.2
71.4
-51.9
64.2
71.3
71.3
nd
nd
nd
nd
-nd
0.01
-nd
nd
nd
nd
0.09
0.09
0.15
0.09
-0.10
0.11
-0.09
0.10
0.11
0.12
0.81
1.20
1.16
0.08
-0.02
0.26
-1.31
0.96
1.14
0.77
89.8
93.7
83.8
83.5
-185.8
255.9
-185.3
204.5
208.7
204.4
-10.5 -77.4
-10.3 -76.2
236
294
0.24
0.39
13.9
30.8
nd
nd
0.09
0.09
0.03
0.23
16.9
81.6
-10.5
-10.5
-10.1
-10.4
-10.4
-77.8
-77.5
-76.0
-76.1
-77.4
227
217
234
240
289
0.24
0.24
0.24
0.25
0.38
14.2
14.2
14.2
15.0
30.7
nd
nd
nd
0.07
nd
0.09
0.09
0.09
0.09
0.08
0.01
0.01
0.02
0.16
0.20
18.6
18.3
23.4
23.6
82.1
-11.7
-11.7
-11.6
-11.4
-10.9
-11.4
-11.3
-11.1
-84.3
-83.8
-83.5
-83.3
-82.2
-82.5
-82.5
-78.2
163
-151
167
169
188
196
215
0.08
0.08
0.08
0.09
0.09
0.13
0.15
0.17
3.0
3.0
3.0
3.1
3.2
21.3
14.3
15.0
0.11
nd
nd
nd
nd
0.02
0.01
nd
0.00
0.01
0.01
0.01
0.01
0.03
0.03
0.05
0.02
0.01
nd
nd
nd
0.70
0.34
0.01
1.0
1.1
1.1
0.9
0.8
2.5
2.7
3.5
-10.9 -81.0
-10.7 -79.3
-10.7 -79.6
-280
247
0.11
0.18
0.17
2.9
17.9
17.9
nd
nd
nd
0.01
0.05
0.05
0.16
0.00
0.05
1.2
4.0
4.1
-10.6 -77.7
-10.3 -76.8
-10.1 -75.0
184
204
244
0.11
0.12
0.18
3.7
3.9
6.2
nd
nd
nd
0.02
0.03
0.04
nd
0.00
0.01
1.7
7.4
94.9
101
APPENDIX A1 – Continued
Sample ID
As
B
Ba
Ca
Mg
Na
Si
Sr
K
(mg/L) (mg/L) (mg/L) (mg/L) (mg/L) (mg/L) (mg/L) (mg/L) (mg/L)
June-2007 (cont'd)
Verde River (cont'd)
VR-55
0.02
0.25
VR-56
0.03
0.21
VR-57
0.03
0.20
VR-61A
0.03
0.26
VR-61B
0.03
0.22
VR-62
0.03
0.39
VR-63
0.04
0.46
VR-63I
0.03
0.25
VR-65
0.03
0.36
VR-66
0.03
0.31
VR-67
0.03
0.31
VR-68
0.03
0.36
Verde River Diversions
VR-11
0.02
0.20
VR-59
0.03
0.26
Verde River Return Flows
VR-22
0.02
0.20
VR-26
--VR-30
0.02
0.23
VR-33
0.02
0.19
VR-60
0.03
0.25
Oak Creek
T-11
0.01
0.05
T-10
0.01
0.02
T-9
0.01
0.06
T-7B
0.01
0.04
T-6
0.01
0.04
T-5
0.02
0.06
T-4C
0.02
0.06
VR-40
0.02
0.06
Wet Beaver Creek
T-7A
0.01
0.01
T-4B
0.03
0.35
T-3
--West Clear Creek
T-4A
0.00
0.02
T-2
0.00
0.02
T-1
0.01
0.11
0.08
0.10
0.12
0.09
0.11
0.06
0.06
0.08
0.07
0.08
0.08
0.06
30.4
62.6
62.8
35.7
63.4
37.0
53.9
34.9
50.3
78.3
71.8
33.9
3.0
3.3
3.6
3.6
3.4
4.8
7.3
3.6
4.5
4.4
4.2
4.3
42.2
44.0
43.2
43.0
43.9
59.8
68.3
42.2
58.0
59.8
60.3
57.9
54.8
56.9
54.2
55.1
55.1
94.1
154.5
54.5
89.6
97.8
101.1
98.3
14.0
18.2
18.9
18.9
19.3
19.2
21.6
18.6
19.3
19.3
18.7
17.2
0.65
1.03
1.00
1.04
1.23
2.23
4.63
1.03
2.61
2.92
2.73
2.16
0.15
0.07
46.1
23.9
2.5
3.6
27.6
42.1
26.4
54.4
9.7
18.8
0.22
0.83
0.12
-0.12
0.16
0.08
25.4
-28.9
50.5
26.1
2.6
-2.7
4.6
3.7
27.0
-28.4
29.6
42.6
27.5
-25.9
27.3
55.3
9.4
-9.4
11.4
18.7
0.17
-0.18
0.24
0.85
0.21
0.24
0.19
0.19
0.17
0.13
0.11
0.13
36.9
36.8
35.9
38.9
40.0
47.4
37.9
51.6
1.2
1.3
1.3
1.3
1.4
1.5
1.6
1.9
17.7
19.8
17.3
19.0
19.6
20.2
20.9
25.0
5.7
5.6
5.9
5.4
6.7
19.6
13.2
15.6
6.7
7.7
6.5
7.2
7.1
7.5
7.8
8.5
0.12
0.14
0.12
0.12
0.12
0.14
0.13
0.22
0.26
0.19
--
28.8
28.8
--
1.9
3.4
--
16.6
28.3
--
7.3
28.5
--
10.8
10.9
--
0.18
0.21
--
0.13
0.09
0.07
39.8
44.5
57.5
1.8
1.9
2.5
24.5
26.7
43.4
7.4
8.1
15.4
9.7
9.8
12.3
0.18
0.25
1.35
102
APPENDIX A1 – Continued
Sample ID
River
km
February/March-2008
Verde River
VR02240802
61.4
VR03110801
55.5
VR03110802
52.4
VR03110803
49.4
VR03110804
43.7
VR03110805
28.0
VR03110806
24.7
VR02240801
20.9
VR03110807
20.9
VR02250802
13.3
VR03110808
13.3
VR02250801
6.5
VR03110809
6.0
Oak Creek
OC03110801 114.9
OC03040801 102.0
OC03040802
72.0
OC03040803
58.5
Wet Beaver Creek
WB02240801 55.0
Latitude/
Northing
Longitude/
Easting
Coordinate
System/
Datum
Date
Sample
Sample
temperstart
ature,
time
(°C)
N34.75043
N34.7226587
N34.7043423
N34.684995
N34.6749589
N34.5840314
N34.5730467
3823515
N34.5504818
3818585
N34.5060714
3815413
N34.4730603
W112.0222
WGS 84
W111.9915142 WGS 84
W111.9717746 WGS 84
W111.9648358 WGS 84
W111.9391617 WGS 84
W111.8774047 WGS 84
W111.8563248 WGS 84
0421884
UTM 12N
W111.8512499 WGS 84
0423164
UTM 12N
W111.8370911 WGS 84
0426491
UTM 12N
W111.8014537 WGS 84
2/24/2008
3/11/2008
3/11/2008
3/11/2008
3/11/2008
3/11/2008
3/11/2008
2/24/2008
3/11/2008
2/25/2008
3/11/2008
2/25/2008
3/11/2008
15:00
------13:30
-12:45
-12:30
--
10.1
------8.5
-10.0
-9.5
--
N34.94685
N34.86229
N34.7653
N34.71799
W111.75421
W111.76192
W111.89095
W111.91609
WGS 84
WGS 84
WGS 84
WGS 84
3/11/2008
3/4/2008
3/4/2008
3/4/2008
11:00
16:30
17:30
18:00
5.0
6.1
9.7
8.7
3836548
0434578
UTM 12N
2/24/2008
11:30
5.8
103
APPENDIX A1 – Continued
Sample ID
Sp.
δ18O δ2H
Cond. pH
(‰) (‰)
(uS/cm)
February/March-2008
Verde River
VR02240802
270
VR03110801
-VR03110802
-VR03110803
-VR03110804
-VR03110805
-VR03110806
-VR02240801
219
VR03110807
-VR02250802
263
VR03110808
-VR02250801
258
VR03110809
-Oak Creek
OC03110801
108
OC03040801
131
OC03040802
217
OC03040803
186
Wet Beaver Creek
WB02240801
85
Alkalinity
NO3
SO4
NO2
Br
(mg/L
Cl
F
ANC as (mg/L) (mg/L) (mg/L) (mg/L) (mg/L) (mg/L)
CaCO3)
8.2
7.7
7.5
7.6
7.5
7.4
7.8
7.8
7.5
8.0
7.4
7.9
7.5
-11.1
-11.0
-11.0
-11.0
-11.1
-11.1
-11.1
-10.7
-11.1
-11.2
-11.1
-10.7
-11.1
-79.6
-77.9
-79.2
-79.0
-78.5
-79.7
-78.5
-75.2
-77.9
-75.7
-78.2
-76.1
-77.3
131
98
98
99
93
90
94
101
80
119
77
115
79
0.17
0.12
0.12
0.12
0.12
0.12
0.12
0.12
0.10
0.15
0.11
0.14
0.10
6.3
5.4
5.1
5.0
5.2
6.1
6.3
6.5
4.7
8.6
5.2
7.7
4.3
0.01
0.01
0.01
nd
nd
nd
0.00
0.00
0.00
0.00
0.00
0.00
0.00
0.02
0.02
0.02
0.02
0.01
0.01
0.01
0.01
0.01
0.01
0.01
0.01
0.01
0.08
0.00
0.00
0.00
0.00
0.00
0.00
0.15
0.00
0.09
0.00
0.10
0.00
8.4
5.5
6.0
6.7
5.6
4.7
7.0
7.1
5.0
12.1
6.6
12.9
6.5
7.3
7.5
8.0
7.8
-11.5
-11.5
-11.4
-11.4
-80.5
-79.4
-80.5
-80.0
-57
101
87
0.08
0.09
0.10
0.10
4.9
7.2
10.0
8.1
nd
nd
0.01
nd
0.00
0.00
nd
0.01
0.00
0.00
0.04
nd
1.7
2.3
2.6
2.4
--
0.09
1.4
nd
nd
0.04
1.3
7.0 -10.4 -71.4
104
APPENDIX A1 – Continued
Sample ID
As
B
Ba
Ca
Mg
Na
Si
Sr
K
(mg/L) (mg/L) (mg/L) (mg/L) (mg/L) (mg/L) (mg/L) (mg/L) (mg/L)
February/March-2008
Verde River
VR02240802
nd
VR03110801
nd
VR03110802
nd
VR03110803
nd
VR03110804
nd
VR03110805
nd
VR03110806
nd
VR02240801
nd
VR03110807
nd
VR02250802
nd
VR03110808
nd
VR02250801
nd
VR03110809
nd
Oak Creek
OC03110801
nd
OC03040801
nd
OC03040802
nd
OC03040803
nd
Wet Beaver Creek
WB02240801
nd
0.07
0.05
0.05
0.05
0.05
0.04
0.04
0.05
0.03
0.06
0.03
0.06
0.03
0.21
0.13
0.12
0.12
0.16
0.13
0.13
0.18
0.12
0.23
0.11
0.20
0.12
32.9
24.0
24.0
24.1
22.7
22.4
22.8
25.3
19.6
29.3
20.2
29.0
19.5
1.3
1.1
1.1
1.1
1.0
1.1
1.0
1.5
0.9
1.4
0.9
1.4
0.9
13.0
9.5
9.7
10.0
9.5
9.2
10.0
11.1
8.3
13.5
8.7
13.3
8.5
11.4
8.1
8.0
8.0
7.4
7.2
8.0
8.4
6.1
11.5
7.0
10.2
6.1
8.4
7.3
7.3
7.4
7.2
6.9
7.3
8.5
7.3
8.3
7.4
8.5
7.5
0.11
0.09
0.09
0.09
0.08
0.09
0.12
0.17
0.10
0.22
0.15
0.22
0.14
0.02
0.02
0.02
0.02
0.19
0.19
0.17
0.17
11.3
13.9
25.9
21.7
0.7
0.8
1.0
0.9
4.9
6.4
11.1
9.3
4.2
5.2
7.4
6.4
6.4
6.8
6.8
6.7
0.05
0.06
0.09
0.08
0.02
0.20
9.3
1.4
4.5
2.2
10.6
0.07
105
APPENDIX A2: Groundwater Geochemical Results
([--]=no data; nd=below detection limit)
Sample ID
Latitude/
Northing
Longitude/
Easting
Coordinate
System/
Datum
Geologic Unit
Date
Sample
start
time
VG09110702
VG10060701
VG10060704
VG02240806
VG03120804
VG03110802
VG02250803
VG02250804
VG10050708
VG09100702
VG10050707
VG03120802
VG11170604
VG11170605
VG09100701
VG09100703
VG09100704
VG09100705
VG09100706
VG09110701
VG10050706
VG10060706
VG10070703
VG02240801
VG02240802
VG03040802
VG03040803
VG03050808
VG03110801
VG03110803
VG11170602
VG11170603
VG11190605
VG09110703
VG10050701
VG10050702
VG10050703
VG10050704
VG10050705
VG10060702
N3441.684
3822182
3825721
3833126
3847038
3877386
3816165
3819845
N3454.779
N3447.230
N3454.948
3860576
N34.8124
N34.81398
N3446.997
N3447.206
N3446.807
N3446.667
N3451.551
N3448.490
3854664
3865492
3856213
3831821
3826285
3835242
3836874
3848588
3854303
3854924
N34.75253
N34.75428
N34.6481
N3432.409
3819597
3819684
3845321
3841992
3846974
3824222
W11157.500
0420628
0421639
0417246
0405870
0433277
0421728
0420016
W11149.530
W11146.682
W11149.273
0411074
W111.82885
W111.83067
W11146.474
W11145.693
W11145.138
W11145.171
W11147.278
W11148.070
0421591
0432629
0420935
0434238
0427988
0429973
0434739
0417087
0425993
0421032
W112.0013
W112.01312
W111.7515
W11150.902
0422272
0422566
0411212
0417364
0418621
0420618
WGS84
UTM 12N
UTM 12N
UTM 12N
UTM 12N
UTM 12N
UTM 12N
UTM 12N
WGS84
WGS84
WGS84
UTM 12N
WGS84
WGS84
WGS84
WGS84
WGS84
WGS84
WGS84
WGS84
UTM 12N
UTM 12N
UTM 12N
UTM 12N
UTM 12N
UTM 12N
UTM 12N
UTM 12N
UTM 12N
UTM 12N
WGS84
WGS84
WGS84
WGS84
UTM 12N
UTM 12N
UTM 12N
UTM 12N
UTM 12N
UTM 12N
Alluvium
Alluvium
Alluvium
Alluvium
Alluvium
Coconino Sandstone
Igneous unit
Igneous unit
Martin Formation
Redwall Limestone
Redwall Limestone
Redwall Limestone
Supai Group
Supai Group
Supai Group
Supai Group
Supai Group
Supai Group
Supai Group
Supai Group
Supai Group
Supai Group
Supai Group
Supai Group
Supai Group
Supai Group
Supai Group
Supai Group
Supai Group
Supai Group
Verde Formation
Verde Formation
Verde Formation
Verde Formation
Verde Formation
Verde Formation
Verde Formation
Verde Formation
Verde Formation
Verde Formation
9/11/2007
10/6/2007
10/6/2007
2/24/2008
3/12/2008
3/11/2008
2/25/2008
2/25/2008
10/5/2007
9/10/2007
10/5/2007
3/12/2008
11/17/2006
11/17/2006
9/10/2007
9/10/2007
9/10/2007
9/10/2007
9/10/2007
9/11/2007
10/5/2007
10/6/2007
10/7/2007
2/24/2008
2/24/2008
3/4/2008
3/4/2008
3/5/2008
3/11/2008
3/11/2008
11/17/2006
11/17/2006
11/19/2006
9/11/2007
10/5/2007
10/5/2007
10/5/2007
10/5/2007
10/5/2007
10/6/2007
14:30
11:30
13:00
16:00
14:00
10:30
12:00
14:30
12:50
11:00
12:30
10:30
11:15
11:25
10:45
11:10
11:20
11:25
15:15
10:00
-16:00
11:15
10:30
11:00
12:15
13:30
12:00
9:00
13:00
8:45
9:15
9:55
16:00
8:30
8:50
9:50
10:15
-12:00
106
APPENDIX A2 – Continued
Alkalinity
Sample Sp.
temper- Cond.
δ18O δ2H (mg/L
F
Sample ID
pH
ANC
ature (uS/
(‰) (‰)
(mg/L)
as
(°C)
cm)
CaCO3
VG09110702 20.8
596 8.1 -10.4 -76.8 256
0.30
VG10060701 20.2 1360 8.2 -10.0 -73.9 543
0.37
VG10060704 20.5 1029 8.3 -10.1 -74.5 538
0.79
VG02240806 15.2
717 7.9 -10 -77.0 343
0.28
VG03120804 18.1
624 8.2 -10.9 -78.1 253
0.32
VG03110802 8.3
1448 7.9 -11.4 -79.4 165
0.22
VG02250803 18.9 1028 7.6 -9.9 -72.1 356
0.34
VG02250804 19.1
702 7.8 -9.2 -69.3 287
0.37
VG10050708 17.4
553 7.9 -11.9 -83.0 220
0.12
VG09100702 20.6
377 8.1 -11.5 -80.6 173
0.16
VG10050707 18.7
859 7.8 -11.6 -82.0 258
0.16
VG03120802 12.6
581 8.2 -11.5 -81.6 264
0.22
VG11170604
---- -11.4 -78.8
--VG11170605 17.5
355 7.1 -11.5 -79.5 214
0.11
VG09100701 20.7
413 8.0 -11.7 -81.0 188
0.18
VG09100703 20.4
317 8.0 -11.7 -80.9 160
0.17
VG09100704 20.9
253 7.8 -11.5 -80.0 127
0.15
VG09100705 20.8
382 8.1 -11.5 -80.0 193
0.20
VG09100706 20.9
323 7.9 -11.8 -82.6 158
0.14
VG09110701 21.1
329 7.9 -11.7 -82.2 169
0.16
VG10050706 24.7
342 8.2 -11.8 -82.5 176
0.14
VG10060706 15.8
475 8.2 -11.7 -81.9 252
0.15
VG10070703 19.6
433 8.2 -11.7 -82.0 219
0.37
VG02240801 10.6
611 8.0 -8.5 -68.0 299
0.17
VG02240802 9.5
420 8.0 -8.5 -67.2 205
0.31
VG03040802 12.0
725 8.1 -11.9 -86.7 402
0.41
VG03040803 16.1
392 7.8 -10.9 -80.0 207
0.17
VG03050808 17.5
589 8.0 -11.7 -81.8 252
0.13
VG03110801 17.5
486 8.0 -11.6 -81.5 259
0.13
VG03110803 17.7
351 8.1 -11.9 -81.5 182
0.21
VG11170602 15.8
495 7.3 -11.5 -78.1 279
0.26
VG11170603 18.6
529 6.9 -11.7 -81.0 261
0.20
VG11190605 19.5
912 7.5 -11.6 -80.6 496
0.15
VG09110703 27.8 1946 8.0 -10.3 -76.2 436
1.05
VG10050701 19.4 1230 8.3 -10.4 -76.0 417
0.54
VG10050702 18.4
855 8.2 -10.1 -75.2 369
0.37
VG10050703 22.5
570 8.2 -11.9 -82.6 256
0.24
VG10050704 20.8
719 8.1 -10.9 -78.5 313
0.41
VG10050705 20.3
361 8.1 -11.8 -81.4 185
0.20
VG10060702 25.1
269 8.2 -10.7 -78.5 359
3.52
NO3
SO4
NO2
Br
Cl
(mg/L) (mg/L) (mg/L) (mg/L) (mg/L)
23.6
65.5
36.2
21.4
18.1
382.2
19.1
19.3
44.3
12.6
110.9
32.8
-4.9
16.3
6.8
4.6
7.9
7.5
7.4
5.0
4.9
9.5
23.0
12.9
9.7
5.8
44.7
10.7
7.0
28.4
28.1
36.9
131.9
72.4
34.6
33.1
32.7
7.4
261.8
0.01
0.27
0.09
nd
nd
nd
nd
nd
0.06
nd
0.41
nd
-nd
nd
nd
nd
nd
nd
nd
nd
nd
nd
nd
nd
nd
nd
nd
nd
0.01
nd
nd
nd
0.54
0.30
0.07
0.04
0.04
nd
0.95
0.11
0.09
0.11
0.09
0.10
0.06
0.23
0.19
0.09
0.06
0.28
0.13
-0.02
0.10
0.02
0.03
0.04
0.03
0.03
0.02
0.03
0.06
0.26
0.14
0.03
0.01
0.12
0.03
0.04
0.07
0.07
nd
0.30
0.16
0.43
1.67
0.13
0.04
nd
8.05
5.03
1.69
0.64
0.26
0.39
0.68
0.38
0.81
2.78
3.72
1.20
-0.00
4.68
0.94
0.73
0.97
2.37
0.78
1.07
3.05
1.99
2.12
1.02
0.00
0.66
0.52
0.05
0.33
0.99
1.22
nd
3.66
3.96
4.43
1.03
24.58
0.89
nd
31.1
150.3
14.6
39.4
71.4
7.2
208.0
78.2
7.6
7.1
18.5
12.7
-1.1
10.2
3.1
2.5
3.6
4.1
3.1
2.3
6.4
4.1
8.6
10.1
13.4
3.2
7.2
4.1
3.6
4.8
6.0
11.3
401.1
164.7
62.3
4.8
15.3
2.7
646.0
107
APPENDIX A2 – Continued
Sample ID
VG09110702
VG10060701
VG10060704
VG02240806
VG03120804
VG03110802
VG02250803
VG02250804
VG10050708
VG09100702
VG10050707
VG03120802
VG11170604
VG11170605
VG09100701
VG09100703
VG09100704
VG09100705
VG09100706
VG09110701
VG10050706
VG10060706
VG10070703
VG02240801
VG02240802
VG03040802
VG03040803
VG03050808
VG03110801
VG03110803
VG11170602
VG11170603
VG11190605
VG09110703
VG10050701
VG10050702
VG10050703
VG10050704
VG10050705
VG10060702
As
B
Ba
Ca
Mg
Na
Si
Sr
K
(mg/L) (mg/L) (mg/L) (mg/L) (mg/L) (mg/L) (mg/L) (mg/L) (mg/L)
0.01
0.02
0.04
0.06
0.02
nd
nd
nd
0.00
0.03
0.00
nd
-0.01
0.03
0.03
0.04
0.03
0.01
0.02
0.02
0.00
0.01
nd
0.05
nd
nd
nd
nd
nd
0.02
0.02
0.10
0.10
0.02
0.02
0.01
0.02
0.03
0.11
0.22
0.41
0.29
0.25
0.15
0.03
0.05
0.04
0.05
0.13
0.04
0.06
-0.03
0.13
0.14
0.10
0.13
0.10
0.09
0.04
0.03
0.04
0.08
0.09
0.51
0.02
0.05
0.04
0.04
0.06
0.06
0.72
0.61
0.69
0.42
0.07
0.30
0.07
0.74
0.49
0.13
0.18
0.31
0.39
1.03
0.13
0.16
0.30
0.28
0.38
0.43
-0.19
0.31
0.28
0.26
0.30
0.37
0.27
0.18
0.22
0.33
0.63
0.19
0.19
0.25
0.37
0.39
0.31
0.68
0.39
0.26
0.13
0.11
0.17
0.49
0.40
0.29
0.02
48.9
77.6
85.8
67.7
61.1
74.7
141.8
87.1
63.3
43.0
90.7
70.4
-49.1
47.8
37.3
28.4
47.3
36.2
41.0
42.6
57.7
55.4
63.4
29.3
63.5
45.3
73.6
60.8
44.7
52.0
33.3
22.5
154.9
56.4
50.2
65.4
72.0
45.0
105.1
2.5
4.8
6.0
3.6
2.7
2.2
2.5
2.9
1.3
2.0
1.8
2.2
-1.3
3.6
1.8
1.7
1.8
2.1
2.6
1.5
2.0
1.8
3.4
5.9
9.4
1.7
1.4
1.5
1.5
2.6
2.3
5.7
9.5
4.1
2.4
2.0
3.1
1.6
15.3
37.7
102.5
70.0
50.4
37.8
34.3
54.6
33.6
23.8
17.8
30.8
33.0
-23.1
19.9
15.5
12.8
18.5
17.7
16.3
18.1
26.8
23.2
32.6
27.1
32.6
24.5
29.4
31.1
19.6
34.0
28.8
37.2
91.8
73.3
63.0
28.3
29.6
18.4
74.8
30.8
99.5
56.5
27.8
32.2
179.9
32.3
30.1
18.1
10.1
39.1
16.1
-5.5
17.2
12.2
8.6
12.4
9.5
10.6
7.7
11.4
9.1
34.7
28.1
65.1
9.3
19.7
9.2
8.0
16.4
20.4
54.4
180.3
127.8
58.5
22.4
50.2
10.0
423.4
32.5
17.9
26.7
28.9
11.6
9.0
18.8
19.7
5.2
8.9
5.8
7.0
-8.2
9.1
8.9
9.0
8.4
8.7
8.5
8.4
17.8
7.7
16.6
34.4
16.6
12.9
6.7
8.9
8.4
23.7
9.1
7.8
32.5
18.1
15.7
9.2
8.7
8.1
49.0
0.30
2.56
4.79
1.31
0.46
0.62
0.59
0.80
0.30
0.14
0.52
0.24
-0.10
0.11
0.13
0.13
0.13
0.10
0.13
0.09
0.19
0.11
0.43
1.11
0.58
0.23
0.24
0.14
0.10
0.33
0.24
0.26
9.35
1.55
1.32
0.20
0.31
0.15
16.26
108
APPENDIX A2 – Continued
Sample ID
Latitude/
Northing
Longitude/
Easting
Coordinate
System/
Datum
Geologic Unit
Date
Sample
start
time
VG10060703
VG10060705
VG10070702
VG10070704
VG10070705
VG10070706
VG02240803
VG02240804
VG02240805
VG02250801
VG02250802
VG02250806
VG02250807
VG03040801
VG03040804
VG03040805
VG03050801
VG03050802
VG03050803
VG03050804
VG03050805
VG03050806
VG03050807
VG03050809
VG03120801
VG03120803
Shea Spring
3824181
3832067
3840993
3840420
3838111
3838089
3823969
3823835
3845352
3827176
3823231
3834806
3837051
3830164
3838422
3831368
3842030
3842187
3841732
3841581
3841756
3842355
3843157
3845944
3848389
3847068
--
0420708
0427108
0409709
0416053
0414298
0414178
0420023
0421603
0406274
0421410
0422121
0410680
0403806
0423181
0422864
0418527
0408583
0410016
0410582
0411067
0410406
0417317
0417590
0418675
0412668
0405879
--
UTM 12N
UTM 12N
UTM 12N
UTM 12N
UTM 12N
UTM 12N
UTM 12N
UTM 12N
UTM 12N
UTM 12N
UTM 12N
UTM 12N
UTM 12N
UTM 12N
UTM 12N
UTM 12N
UTM 12N
UTM 12N
UTM 12N
UTM 12N
UTM 12N
UTM 12N
UTM 12N
UTM 12N
UTM 12N
UTM 12N
--
Verde Formation
Verde Formation
Verde Formation
Verde Formation
Verde Formation
Verde Formation
Verde Formation
Verde Formation
Verde Formation
Verde Formation
Verde Formation
Verde Formation
Verde Formation
Verde Formation
Verde Formation
Verde Formation
Verde Formation
Verde Formation
Verde Formation
Verde Formation
Verde Formation
Verde Formation
Verde Formation
Verde Formation
Verde Formation
Verde Formation
Verde Formation
10/6/2007
10/6/2007
10/7/2007
10/7/2007
10/7/2007
10/7/2007
2/24/2008
2/24/2008
2/24/2008
2/25/2008
2/25/2008
2/25/2008
2/25/2008
3/4/2008
3/4/2008
3/4/2008
3/5/2008
3/5/2008
3/5/2008
3/5/2008
3/5/2008
3/5/2008
3/5/2008
3/5/2008
3/12/2008
3/12/2008
5/29/2008
12:30
13:45
10:30
14:20
15:00
15:20
12:00
13:45
14:30
9:30
10:15
17:00
18:00
10:00
15:00
15:45
8:00
9:00
9:30
10:00
10:15
11:00
11:30
13:00
9:00
13:45
--
109
APPENDIX A2 – Continued
Alkalinity
Sample Sp.
temper- Cond.
δ18O δ2H (mg/L
F
Sample ID
pH
ANC
ature (uS/
(‰) (‰)
(mg/L)
as
(°C)
cm)
CaCO3
VG10060703 23.7 2210 8.2 -10.7 -77.7 414
2.56
VG10060705 21.8
912 8.3 -10.1 -74.3 388
0.41
VG10070702 19.4
589 8.3 -11.0 -79.5 268
0.38
VG10070704 21.0 1040 8.2 -11.6 -83.4 541
0.33
VG10070705 19.2
507 8.3 -11.3 -80.4 235
0.45
VG10070706 18.6 1075 8.3 -11.3 -79.4 379
0.22
VG02240803 22.1
980 8.0 -10.3 -76.0 273
0.67
VG02240804 18.1
997 7.6 -10.1 -75.1 372
0.72
VG02240805 10.8
926 7.7 -10.6 -78.0 303
0.25
VG02250801 14.9
576 7.9 -10.6 -76.7 283
0.33
VG02250802 19.0 1121 7.7 -10.6 -77.2 341
0.65
VG02250806 11.5
454 8.1 --241
0.55
VG02250807 8.9
1040 8.0 -10.4 -75.7 425
0.33
VG03040801 15.6
715 7.9 -10.4 -76.3 377
0.16
VG03040804 14.7
305 8.1 -11.0 -77.0 155
0.16
VG03040805 18.3
649 8.1 -10.6 -77.3 293
0.36
VG03050801 15.7
553 8.1 -11.5 -82.5 259
0.34
VG03050802 16.7
664 8.0 -11.3 -80.2 234
0.24
VG03050803 11.0 1374 8.0 -10.7 -76.9 374
0.28
VG03050804 17.0
539 8.1 -11.9 -81.6 255
0.19
VG03050805 9.6
1163 8.0 -10.4 -75.9 331
0.27
VG03050806 18.0
679 8.0 -11.0 -77.3 347
0.51
VG03050807 19.9 1220 7.7 -11.3 -80.2 603
0.36
VG03050809 18.5
526 8.2 -11.5 -82.7 260
0.24
VG03120801 13.1
520 8.2 -11.0 -79.4 258
0.19
VG03120803 19.0
505 8.1 -11.0 -78.3 239
0.31
Shea Spring 20.3
547 7.3 -12.0 -82.4
-0.24
NO3
SO4
NO2
Br
Cl
(mg/L) (mg/L) (mg/L) (mg/L) (mg/L)
200.4
55.9
27.0
25.4
24.1
104.8
24.3
62.8
90.2
19.3
59.8
11.5
49.3
21.6
6.7
23.3
19.1
70.1
182.7
29.7
134.5
12.5
59.6
19.5
18.1
16.4
28.0
0.70
0.13
0.02
0.03
nd
0.39
nd
nd
nd
nd
nd
nd
nd
nd
0.01
nd
0.01
nd
nd
nd
nd
0.01
nd
0.01
nd
nd
nd
nd
0.09
0.13
0.07
0.07
0.24
0.08
0.15
0.26
0.08
0.18
0.08
nd
0.01
0.01
0.10
0.11
0.22
nd
0.08
nd
0.05
0.12
0.07
0.16
0.07
0.06
0.01
13.15
3.14
1.60
1.64
0.03
nd
2.11
1.45
0.57
0.78
0.32
0.08
0.06
0.13
1.52
0.74
3.10
11.70
0.24
9.18
1.01
1.92
0.32
3.17
0.25
0.92
450.2
12.3
13.6
22.9
5.3
53.3
220.6
96.6
71.8
21.1
158.5
7.2
112.0
6.2
3.3
42.2
30.9
10.5
67.7
4.5
86.8
26.3
24.8
6.2
6.0
18.9
4.6
110
APPENDIX A2 – Continued
Sample ID
VG10060703
VG10060705
VG10070702
VG10070704
VG10070705
VG10070706
VG02240803
VG02240804
VG02240805
VG02250801
VG02250802
VG02250806
VG02250807
VG03040801
VG03040804
VG03040805
VG03050801
VG03050802
VG03050803
VG03050804
VG03050805
VG03050806
VG03050807
VG03050809
VG03120801
VG03120803
Shea Spring
As
B
Ba
Ca
Mg
Na
Si
Sr
K
(mg/L) (mg/L) (mg/L) (mg/L) (mg/L) (mg/L) (mg/L) (mg/L) (mg/L)
0.10
0.02
0.02
0.01
0.02
0.04
0.08
0.15
nd
0.04
0.06
0.03
nd
nd
nd
0.02
nd
0.02
0.02
nd
0.03
nd
0.03
nd
nd
0.03
--
0.54
0.36
0.14
0.34
0.08
0.27
0.27
0.25
0.09
0.21
0.38
0.08
0.03
0.30
0.03
0.19
0.15
0.08
0.38
0.05
0.36
0.37
0.53
0.12
0.05
0.10
--
0.03
0.18
0.55
0.40
0.67
0.61
0.07
0.23
0.21
0.52
0.10
0.42
0.18
0.32
0.22
0.34
0.59
0.58
0.41
0.55
0.23
0.26
0.35
0.16
0.40
0.42
--
97.7
6.0
47.8
118.0
45.2
107.6
60.3
82.5
83.7
58.5
90.2
30.1
124.8
84.5
45.4
58.9
45.9
65.4
76.0
59.7
78.1
74.8
144.4
34.2
70.1
46.4
--
15.2
1.8
2.3
7.5
2.9
2.7
9.1
5.9
2.0
3.0
5.6
1.3
0.4
2.4
1.6
2.9
1.4
3.6
3.2
1.8
3.3
4.4
5.9
8.0
1.8
3.1
--
61.4
3.7
40.4
46.9
34.0
56.0
46.7
54.5
61.3
37.7
57.0
42.6
54.9
38.2
12.9
42.7
43.8
40.3
86.5
32.7
81.9
24.5
53.1
18.7
29.7
30.3
--
324.4
212.5
24.0
63.2
17.1
57.2
87.6
67.0
35.3
24.8
88.6
14.1
51.7
30.4
5.9
30.8
19.7
21.6
103.2
17.2
63.8
56.4
75.0
61.6
10.6
27.3
--
48.2
13.4
21.8
17.2
33.3
24.3
55.1
32.4
19.5
24.1
32.3
41.1
21.8
13.0
13.2
22.4
33.1
14.8
28.3
9.6
36.8
7.4
9.0
26.7
13.8
11.5
--
14.30
0.04
0.37
0.59
0.44
0.43
21.02
7.28
0.62
0.73
3.91
0.25
0.28
0.31
0.21
0.67
0.32
0.54
0.53
0.25
0.65
0.22
0.46
0.12
0.15
0.44
--
111
APPENDIX B: PCA Results for November 2006 Data
4
3
1
2
% of
variance
Cumulative
%
1
58
2
18
3
13
4
6
Component
5
6
7
3
1
1
58
75
88
94
98
99
1
1
1
1
1
-0.54
-0.32
0.04
0.17
-0.07
0.11
0.38
-0.25
0.17
-0.57
0.10
-0.02
-0.34
0.16
-0.76
-0.17
0.29
-0.08
0.36
-0.02
-0.16
-0.08
0.48
0.32
-0.07
0.13
-0.31
0.12
-0.16
0.02
-0.14
-0.70
-0.05
-0.04
-0.20
-0.06
0.51
-0.30
0.22
0.22
0.63
-0.14
0.16
-0.28
-0.25
0.38
0.72
-0.03
-0.31
-0.22
0.03
-0.05
0.02
0.05
-0.36
0.34
-0.14
0.09
-0.02
-0.37
0.47
0.30
-0.55
-0.04
0.33
-0.03
0.39
-0.58
0.41
0.25
0.27
-0.17
-0.25
-0.08
0.20
-0.12
-0.24
-0.26
-0.07
0.25
0.24
-0.15
0.34
-0.63
-0.03
-0.17
0.08
0.48
0.04
-0.06
0.25
-0.02
0.37
-0.01
0.27
-0.03
-0.85
-0.08
0.07
0.21
-0.21
0.11
-0.03
-0.44
-0.55
0.22
0.14
-0.02
0.04
0.58
Tracer Coefficients
δ18O
0.21
δ 2H
0.29
Conductivity
0.37
Ca
0.05
Mg
0.36
Na
0.35
Sr
0.33
Alkalinity
0.29
Cl
0.38
Br
-0.02
SO4
0.38
8
0
9
0
10
0
11
0
112
APPENDIX C: PCA Results for June 2007 Data
Component
Verde River
(n=46)
1
% of variance
75
Cumulative %
75
Tracer Coefficients
Conductivity
0.38
Ca
0.22
Mg
0.37
Na
0.37
Sr
0.36
Alkalinity
0.30
Cl
0.37
Br
0.18
SO4
0.38
2
14
89
3
5
94
4
4
98
5
1
99
6
1
100
7
0
100
8
0
100
9
0
100
-0.10
0.54
0.01
-0.21
-0.23
0.23
-0.18
0.70
-0.16
0.03
-0.77
0.04
-0.01
-0.13
0.49
-0.06
0.38
0.00
-0.03
0.24
-0.06
-0.11
-0.06
0.77
-0.14
-0.55
-0.10
0.30
-0.02
0.57
-0.40
-0.57
-0.12
0.03
-0.16
0.23
-0.14
-0.03
0.51
0.20
0.28
-0.07
-0.77
-0.03
0.00
0.01
0.08
-0.20
0.71
-0.61
-0.01
-0.18
-0.03
0.23
-0.81
-0.01
0.39
0.13
-0.11
0.06
0.40
-0.04
-0.01
-0.29
0.01
-0.26
-0.30
0.11
0.03
-0.17
0.04
0.85
Component
VR Reach 1
(n=9)
1
% of variance
41
Cumulative %
41
Tracer Coefficients
Conductivity -0.46
Ca
-0.03
Mg
0.14
Na
0.18
Sr
0.00
Alkalinity
-0.40
Cl
0.48
Br
0.47
SO4
0.35
2
25
66
3
17
83
4
10
93
5
4
96
6
3
99
7
1
100
8
0
100
9
0
100
-0.07
-0.56
-0.42
0.39
-0.55
0.21
0.09
0.02
-0.08
-0.02
-0.39
0.50
-0.51
-0.45
-0.31
-0.09
-0.03
-0.18
-0.47
0.25
-0.10
0.20
-0.02
-0.28
-0.24
0.05
-0.73
0.11
0.14
-0.67
-0.55
-0.08
-0.30
0.35
-0.04
-0.08
0.16
0.14
-0.01
-0.22
-0.12
0.40
-0.10
0.83
-0.17
-0.26
-0.16
0.18
-0.18
0.26
0.49
0.61
-0.17
-0.37
-0.07
-0.63
-0.21
-0.13
0.62
-0.15
-0.29
0.20
-0.03
-0.68
0.09
-0.15
-0.35
-0.13
0.33
-0.34
-0.12
0.37
Component
VR Reach 2
(n=17)
1
52
52
% of variance
Cumulative %
Tracer Coefficients
Conductivity
0.37
Ca
0.22
Mg
0.37
Na
0.40
Sr
0.33
Alkalinity
0.22
Cl
0.39
Br
0.35
SO4
0.31
2
23
76
3
12
88
4
6
94
5
3
96
6
2
98
7
1
99
8
1
100
9
0
100
-0.36
0.54
-0.28
-0.09
0.45
-0.06
0.10
0.31
-0.42
0.07
0.18
0.24
-0.35
0.13
-0.80
0.06
-0.02
0.34
-0.15
0.45
0.38
0.09
0.15
0.22
-0.64
-0.34
0.17
0.07
0.02
-0.18
0.31
0.33
-0.13
0.36
-0.78
-0.09
-0.42
-0.13
0.25
-0.56
0.16
0.41
0.40
-0.16
0.24
0.68
0.26
0.07
-0.50
-0.05
0.20
0.03
-0.15
-0.39
-0.16
-0.26
0.69
0.14
0.03
-0.18
0.05
0.01
-0.61
-0.20
0.52
0.11
0.14
-0.72
-0.02
0.37
-0.10
-0.02
113
APPENDIX C – Continued
Component
VR Reach 3
(n=7)
1
% of variance
78
Cumulative %
78
Tracer Coefficients
Conductivity -0.36
Ca
-0.36
Mg
-0.34
Na
-0.29
Sr
-0.36
Alkalinity
-0.19
Cl
-0.36
Br
-0.35
SO4
-0.36
2
13
90
3
7
97
4
2
99
5
1
100
6
0
100
7
0
100
8
0
100
9
0
100
-0.19
0.14
0.40
-0.16
0.17
-0.80
0.21
-0.21
0.04
-0.11
0.28
-0.11
-0.79
0.29
0.16
0.08
0.35
-0.20
0.52
-0.47
0.06
0.05
0.22
-0.29
-0.09
0.36
-0.48
0.08
-0.42
-0.37
-0.20
-0.25
-0.14
0.64
0.14
0.38
0.11
-0.18
-0.18
-0.02
0.61
0.22
0.26
-0.65
-0.11
0.47
0.58
-0.42
0.05
-0.28
-0.21
0.16
-0.19
-0.28
-0.32
0.10
-0.60
0.35
0.43
-0.30
-0.17
0.29
0.14
0.46
-0.03
-0.09
-0.33
0.10
-0.14
-0.54
-0.15
0.58
Component
VR Reach 4
(n=13)
% of variance
Cumulative %
1
77
77
Tracer Coefficients
Conductivity
-0.36
Ca
-0.36
Mg
-0.34
Na
-0.29
Sr
-0.36
Alkalinity
-0.19
Cl
-0.36
Br
-0.35
-0.36
SO4
2
12
89
3
7
96
4
2
98
5
1
100
6
0
100
7
0
100
8
0
100
9
0
100
-0.19
0.14
0.40
-0.16
0.17
-0.80
0.21
-0.21
0.04
-0.11
0.28
-0.11
-0.79
0.29
0.16
0.08
0.35
-0.20
0.52
-0.47
0.06
0.05
0.22
-0.29
-0.09
0.36
-0.48
0.08
-0.42
-0.37
-0.20
-0.25
-0.14
0.64
0.14
0.38
0.11
-0.18
-0.18
-0.02
0.61
0.22
0.26
-0.65
-0.11
0.47
0.58
-0.42
0.05
-0.28
-0.21
0.16
-0.19
-0.28
-0.32
0.10
-0.60
0.35
0.43
-0.30
-0.17
0.29
0.14
0.46
-0.03
-0.09
-0.33
0.10
-0.14
-0.54
-0.15
0.58
114
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