Assessment of Spring Chemistry Along the South Rim of Grand Canyon in Grand Canyon National Park, Arizona —A U.S

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Prepared in cooperation with the NATIONAL PARK SERVICE Assessment of Spring Chemistry Along the South Rim of Grand Canyon in Grand Canyon National Park, Arizona —A U.S. Geological Survey and National Park Service Partnership —

Spring flow from the south rim of Spring Resource Issues —Changes in the quality, quantity, Grand Canyon (fig. 1) is an important and sustainability of flow from springs resource in Grand Canyon National Park Tributary streams occupy 0.003 percent can affect the long-term health of (GCNP). Springs offer refuge to endemic of the area of Grand Canyon; however, biological communities and riparian and exotic terrestrial wildlife species and 36 percent of the total riparian flora habitats associated with these areas. help maintain the riparian areas associated exists within those confines (John Rihs, —Climate variability can affect with this resource. Recent real estate hydrologist, GCNP, written commun., spring flow and thus the riparian habitats development on the Coconino Plateau 2002). Baseline, seasonal, and annual associated with these areas. (fig. 1), a subregion of the Colorado Plateau water-quality data from springs along —Ground-water pumpage from the south of Grand Canyon, has heightened the south rim and identification of spring Redwall and Muav Limestones south of the awareness of environmental groups, sources are needed to address four issues Grand Canyon may affect spring flow. commercial developers, and resource identified by GCNP: managers to the importance of spring —The quality of water from springs �� resources. Native Americans in the Grand and seeps can limit recreational use of Canyon region, such as the Havasupai the water. Tribe, are concerned that ground-water pumpage may affect the spring resources. �� For Native Americans, springs are not �� only economically important but also �� culturally significant. �� The U.S. Geological Survey (USGS) � and GCNP began a cooperative program � �� in 1999 under the auspices of the Water- �� Quality Monitoring and Assessment � Partnership, a Clean Water Action Plan �� program (2002), shared between the �� USGS and the National Park Service ��

(NPS). Nineteen springs have been �� sampled to date that issue from the �� Redwall and Muav Limestones along the south rim of Grand Canyon. ��

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�� Figure 1. Location of the study area.

U.S. Department of the Interior USGS Fact Sheet 096-02 U.S. Geological Survey U.S. Geological Survey Population growth on the Coconino Along the Colorado River, the climate is The hydrogeology of the deeply buried Plateau has raised concern about the continental and arid. Precipitation ranges Redwall and Muav Limestones and potential demise of spring resources of from 5.9 in. at Lees Ferry (river mile 0) to the hydraulic connection of these units Grand Canyon. Ground-water develop- 9.1 in. at Phantom Ranch (river mile 86; with the overlying Pennsylvanian and ment near the communities of Valle and Sellers and others, 1986). Permian rocks of the Coconino Plateau Tusayan, Arizona (fig. 1), has prompted near Grand Canyon are poorly known. GCNP to monitor flow from selected Water-Bearing Units The water-bearing units are recharged springs along the south rim of Grand primarily by precipitation that infiltrates Canyon. Variability in spring flow can The water-bearing units from which outcrops of volcanic rocks, the Kaibab indicate stresses caused by ground-water springs along the south rim typically Formation, and the Coconino Sandstone development in the basins, or indicate issue are limestones and sandstones in the higher altitudes of the Coconino changes in the regional climate. of Paleozoic age (fig. 2). Water in the Plateau (Johnson and Sanderson, 1968).

Redwall and Muav Limestones is the Faults and fractures, many widened Objectives of the Study primary source of spring flow along by solution, create zones of secondary the south rim of Grand Canyon owing permeability that could be the primary The objectives of the study are to: to faults and fractures (Metzger, 1961; controls of ground-water movement. —Accurately locate and map significant Huntoon, 1974). Below the Muav Ground water in the south rim area springs issuing from the Redwall and the Limestone, the less permeable Bright and in the northern parts of the plateau Muav Limestones. Angel Shale acts as a physical barrier to generally flows toward the south rim and —Describe the general water chemistry downward movement of ground water discharges at springs and seeps in Grand of springs. from overlying rocks (Huntoon, 1974). Canyon (fig. 2). Springs and seeps —Verify the source of water dis- Seeps and springs also occur from typically occur at geologic contacts charging at springs and determine the the Cambrian Tapeats Sandstone, which where water-bearing rocks are underlain approximate age of spring water. underlies the Bright Angel Shale, and in the by less permeable rocks. Large springs in —Measure spring-flow discharge. Pennsylvanian and Permian Supai Group the canyon are associated with regional and the Permian Coconino Sandstone faults. Very little is known about the In addition to data collection at that overlie the Redwall Limestone. movement of ground water through the springs, water samples are proposed to rocks of the plateau; therefore, travel be collected from wells in Tusayan and �� times to discharge points are unknown. Valle south of Grand Canyon. Wells in these communities tap the Redwall Limestone or Muav Limestone for water supply and are believed to lie in the path of ground-water flow to south rim �� springs. Analyses of water samples from �� these wells are critical for determining �� the sources and flow paths of water that discharges at springs along the south rim �� of Grand Canyon. ��

Physical Setting ��

The study area extends across the Coconino Plateau, an area of about �� 2 5,000 mi in the southern part of the �� Colorado Plateau in northern Arizona �� (fig. 1), to allow collection of information on spring source areas and ground-water development. The Coconino Plateau �� extends from GCNP south to the �� Mogollon Rim, and from near Winslow northwest to the Hualapai Indian ��

Reservation. Altitudes within the study �

�� area range from 12,500 ft at San Francisco �

� �� Mountain to 2,400 ft on the Colorado ��

River near Grand Canyon. The greatest �� rainfall occurs during the southwestern �� monsoon from mid-June to early October. � � �

Snowfall on the Coconino Plateau can �� be significant at higher elevations and �� accounts for the greatest portion of the total precipitation in these areas. The climate of the Coconino Plateau changes Figure 2. Schematic diagram of the geology of the study area showing a generalized with altitude. Above 7,000 ft, annual south-to-north cross section from the south rim of Grand Canyon near Tusayan to the precipitation varies from 19.1 in. on Colorado River. Springs receive recharge from precipitation that infiltrates rocks along the Kaibab uplift (fig. 1) to about 21 in. the south rim and from ground water that flows to the springs from areas south of the near Flagstaff (Sellers and others, 1986). south rim. Sampling Approach and Table 1. Springs sampled, field measurements, and analytes Chemical Analyses Springs sampled: Blue Spring, Red Canyon Spring, JT Spring, Miners Spring, Cottonwood Spring, Grapevine East Spring, Grapevine Main Spring, Lonetree Spring, Sam Magee Spring, Burro Spring, Data have been collected from Pipe Spring, Pumphouse Spring, Horn Creek, Salt Creek Spring, Monument Spring, Hawaii Spring, Hermit Spring, Boucher East Spring, Mohawk Spring 19 springs since the program began in 1999 (table 1). Analyses of the stable Field measurements Analytes 13 12 isotopes of carbon ( C and C) are pH and temperature Major ions used to determine recharge areas. These Specific conductance Trace metals isotopes are affected by photosynthesis and other biological and environmental Dissolved oxygen Rare earth elements factors (Drever, 1988). The 13C/12 C Alkalinity Nutrients Stable isotopes value in water is dependent on the Spring discharge (oxygen, hydrogen, carbon, and strontium) isotopic composition of carbon dioxide Radiogenic isotopes in the soil (rock) at the recharge area Elevation and location of spring outlet (tritium and carbon-14) and on reactions between the water Radionuclides—gross alpha/beta and carbonate minerals along the flow path (Lopes and Hoffmann, 1997). Strontium isotope data (87Sr and 86Sr) Carbon-14 has a half-life of also help to identify flow paths. For 5,730 years, and tritium has a half-life example, water that receives recharge of 12.3 years. Large amounts of both primarily through limestone has a were released into the atmosphere heavier strontium composition (larger during testing of nuclear weapons 87Sr/86Sr value) than water that receives during the 1950s and 1960s (Fritz and recharge primarily through volcanic Fontes, 1980). Baseline water chemistry rocks. Data from the analyses of oxygen determined from analyses of major ions (18 O and 16O) and hydrogen (2H and and other constituents can allow future 1H) isotopes provide information about studies to measure changes in chemistry sources of recharge from rainfall or over time and potentially identify snowmelt and whether the recharge factors responsible for the changes. source has been affected by evaporation. Concentrations of trace and rare earth Analyses of the radiogenic isotopes of elements also can potentially provide carbon (1 4 C) and hydrogen (3H, tritium) information useful for identifying are used to determine ground-water recharge areas. Nutrient analysis age, which can be used to infer travel provides information on the general times along ground-water flow paths. water quality of the spring water. Monument Spring at source, first major canyon to the east of Hermit Creek

112°15' 10' 5' 112° 111°55'

Phantom Ranch

Sam Magee k

e Hermit Creek k P Spring e e e i r above Tonto Trail Horn r p C e o 36°5' C near Grand Creek C lo r Canyon (09403043 ) Burro Spring a Boucher d East Spring Hawaii Salt Creek o t Spring Spring n Pipe Spring i e Pumphouse C m d r r Spring e Lonetree r a e e Spring G Pumphouse Wash k H Monument Spring near Spring Grand Canyon (09403013 ) e Hermit Source Riv r

Spring Grapevine East Spring C

n w Cottonwood Spring Grapevine Main Spring o o d Cottonwood Spring above Miners Spring C Red confluence with r e Canyon Cottonwood Creek near e JT Spring Spring Grand Canyon (09402450) k 36° Base from U.S. Geological Survey EXPLANATION 0 3 MILES digital elevation model data, 1:24,000 Universal Transverse Mercator Projection, Sampled spring—tail Streamflow-gaging 0 3 KILOMETERS Zone 12 points in direction station with station of spring flow number Figure 3. Sampled springs and streamflow-gaging stations on the south rim of Grand Canyon. Long-Term Needs of GCNP Springs that issue from other stratigraphic References units in the park that overlie and underlie GCNP has the responsibility of the Redwall and Muav Limestones will be Clean Water Action Plan, 2000, accessed protecting the natural resources of Grand sampled to determine the hydrogeologic February 1, 2002, at URL Canyon and depends on partnerships with relations among the units. http://www.cleanwater.gov/news/ government and private organizations to B. Expand spring discharge moni- fact_sheet.html/ address resource issues. Long-term needs toring. Continuous stage will be recorded Drever, J.I., 1988, The geochemistry of GCNP require a knowledge base and discharge will be measured on of natural waters: Englewood of the Redwall and Muav Limestones Cottonwood Creek, Pumphouse Wash, Cliffs, New Jersey, Prentice-Hall and other water-bearing units of the and Hermit Creek (fig. 3). Periodic Publishers, 437 p. Colorado Plateau including the Coconino measurements will be made at selected Sandstone and Supai Group, in order to springs that are believed to issue from Fritz, P., and Jean-Charles Fontes, properly manage and protect the seeps the Redwall-Muav Limestone aquifer. 1980, Handbook of environmental and springs of the park. To help achieve Additional spring-flow gages may isotope geochemistry, v. 1–2: this need, GCNP has initiated several be installed to increase monitoring Amsterdam, Elsevier Scientific programs and is pursuing continued coverage and to further document Publishing Company, 557 p. or expanded programs comprising long-term changes in spring flow. Huntoon, P.W., 1974, The karstic monitoring and research components C. Develop and support geologic groundwater basin of the Kaibab including the following: and geophysical framework. Gravity Plateau, Arizona: Washington, D.C., A. Water-chemistry data collection, and aeromagnetic data are being American Geophysical Union, Water compilation, and evaluation. The collec- used in the ongoing geologic surface Resources Research, v. 10, no. 3, tion and evaluation of water chemistry mapping and geophysical evaluation. p. 579–590. data will continue as part of the park’s This data will provide information on effort to identify the source of water the geologic structure that controls Johnson, P.W., and Sanderson, R.B., to each spring and the geologic and regional ground-water flow on the 1968, Spring flow into the Colorado water-quality characteristics of each Coconino Plateau and spring discharge River Lees Ferry to Lake Mead, spring. Future data collection will along the south rim of Grand Canyon. Arizona, Water-Resources Report involve inventorying new springs, D. Develop and support of biologic number 34, Arizona State Land repeat sampling at selected sites to inventory, habitat mapping, and habitat Department, 26 p. help determine seasonal variability, and modeling. Grand Canyon springs and Lopes, T.J., and Hoffmann, J.P., 1997, collection of data from ground-water seeps often support rare, endangered, Geochemical analyses of ground- wells on the Coconino Plateau. Selected endemic, and other species of special water ages, recharge rates, and chemical constituents will be added to concern. Preserving and managing these hydraulic conductivity of the N the analyses to refine the age estimates areas cannot be done without baseline 36 aquifer, Black Mesa Area, Arizona, for spring waters. For example, Cl biological and riparian information. U.S. Geological Survey Water- and chlorofluorocarbons (CFCs) from The park and its cooperators Resources Investigations Report selected sites could be analyzed to continue to collect baseline data on 96 – 4190, 42 p. provide additional information in support ecosystem health that are necessary of estimates based on 14C and 3H data. for an effective monitoring program. Metzger, D.G., 1961, Geology in relation to availability of water — Robert J. Hart, John Rihs (NPS), along the south rim Grand Canyon Howard E. Taylor, and Stephen A. Monroe National Park, Arizona: U.S. Geological Survey Water-Supply Paper 1475— C, 138 p. Sellers, W.D., Hill, R. H., and Sanderson- Rae, M., 1986, Arizona Climate, The First Hundred Years. Tucson:

University of Arizona Department of Atmospheric Sciences, 80 p.

For further information, contact: Robert J. Hart U.S. Geological Survey, WRD 2255 North Gemini Drive Flagstaff, Arizona 86001

E-mail: [email protected] or visit home page http://az.water.usgs.gov Boucher Spring downstream from source, first major canyon to the west of Hermit Creek GCNP website: www.nps.gov/grca/water