The Navajo Nation, the City of Flagstaff (COF), and the U.S. Geological Survey (USGS) maintain a cooperative monitoring program with other local and State agencies for groundwater in the C aquifer (Coconino aquifer) in the Little Colorado River Basin. The goal of this program is to determine baseline groundwater conditions in the C aquifer and other water-bearing zones before significant development in this area occurs and to monitor long-term changes in groundwater levels, water use, surface water, and water chemistry.
Site information and access to site data are available via the C-Aquifer Monitoring Program interative map. Data collected for the program from 2005 to 2011 were published in Open-File Report 2012-1196 (Brown and Macy, 2012). Data collected for the program from 2012 to 2019 were published in Open-File Report 2021-1051 (Jones and Robinson, 2021). Additional reports evaluating data collected for this program will be produced as needed.
Groundwater resources of the C aquifer in the Little Colorado River Basin are already being affected by groundwater withdrawals for municipal, agriculture, and industrial water uses throughout the upper and middle parts of the basin (Hart and others, 2002). Proposed groundwater development from the C aquifer in the Leupp area includes: 1) the use of a potential well field to the south of Leupp by the Navajo Nation to supply water to southern and western reservation communities, 2) a future water supply for the City of Flagstaff at Red Gap Ranch adjacent to the Leupp wellfield, 3) a future water supply for the Navajo Twin Arrows Casino and new subdivisions east of Flagstaff, and 4) supporting continuing development along the Little Colorado River valley up gradient from Leupp. Additional development of groundwater resources in this area could also occur to improve water supplies for communities in the western part of the Navajo Nation (Leupp, Dilkon, Red Lake, Sebi Delka, etc.). Changing water levels could impact the base flow of lower Clear Creek, lower Chevelon Creek, and the Little Colorado River where riparian habitat support threatened and endangered species and other species of interest in addition to areas of cultural significance to the Navajo Nation and Hopi Tribe.
Objective
To establish current baseline information for the C aquifer before significant additional groundwater development occurs around the Leupp area, and to continue monitoring for long-term changes in groundwater levels, water use, and water chemistry.
Approach
A monitoring network has been established to collect hydrologic data from the C aquifer. Data are collected that describe the groundwater and surface-water systems. Continuous measurements of groundwater levels are made at 5 observation wells, and quarterly groundwater measurements are made at 12 additional wells. Water-level measurements from an additional 18 wells measured by the Arizona Department of Water Resources and the City of Flagstaff are also included when available. Discharge and water-quality field parameters are collected at springs and along Lower Chevelon Creek, and Lower Clear Creek to continue to document and characterize the quantity and quality of water resources at the western and southern end of the Navajo Nation. Seepage investigations are conducted on lower Clear Creek, lower Chevelon Creek, and the Little Colorado River to evaluate the base flow component of these streams.

Below are publications associated with this project.
Groundwater and surface-water data from the C-aquifer monitoring program, Northeastern Arizona, 2012–2019
Groundwater, surface-water, and water-chemistry data from C-aquifer monitoring program, northeastern Arizona, 2005-11
Geologic, hydrologic, and chemical data from the C aquifer near Leupp, Arizona
Generalized hydrogeology and ground-water budget for the C Aquifer, Little Colorado River Basin and parts of the Verde and Salt River Basins, Arizona and New Mexico
Below are data or web applications associated with this project.
C-Aquifer Monitoring Program
The Coconino aquifer (C aquifer) supplies water to northeastern Arizona. Proposed increases in groundwater withdrawal to meet population demands, coupled with ongoing drought conditions, increase the potential for water-level changes in the aquifer. The USGS monitors groundwater and surface-water conditions in northeastern Arizona.
Below are partners associated with this project.
- Overview
The Navajo Nation, the City of Flagstaff (COF), and the U.S. Geological Survey (USGS) maintain a cooperative monitoring program with other local and State agencies for groundwater in the C aquifer (Coconino aquifer) in the Little Colorado River Basin. The goal of this program is to determine baseline groundwater conditions in the C aquifer and other water-bearing zones before significant development in this area occurs and to monitor long-term changes in groundwater levels, water use, surface water, and water chemistry.
Site information and access to site data are available via the C-Aquifer Monitoring Program interative map. Data collected for the program from 2005 to 2011 were published in Open-File Report 2012-1196 (Brown and Macy, 2012). Data collected for the program from 2012 to 2019 were published in Open-File Report 2021-1051 (Jones and Robinson, 2021). Additional reports evaluating data collected for this program will be produced as needed.
Groundwater resources of the C aquifer in the Little Colorado River Basin are already being affected by groundwater withdrawals for municipal, agriculture, and industrial water uses throughout the upper and middle parts of the basin (Hart and others, 2002). Proposed groundwater development from the C aquifer in the Leupp area includes: 1) the use of a potential well field to the south of Leupp by the Navajo Nation to supply water to southern and western reservation communities, 2) a future water supply for the City of Flagstaff at Red Gap Ranch adjacent to the Leupp wellfield, 3) a future water supply for the Navajo Twin Arrows Casino and new subdivisions east of Flagstaff, and 4) supporting continuing development along the Little Colorado River valley up gradient from Leupp. Additional development of groundwater resources in this area could also occur to improve water supplies for communities in the western part of the Navajo Nation (Leupp, Dilkon, Red Lake, Sebi Delka, etc.). Changing water levels could impact the base flow of lower Clear Creek, lower Chevelon Creek, and the Little Colorado River where riparian habitat support threatened and endangered species and other species of interest in addition to areas of cultural significance to the Navajo Nation and Hopi Tribe.
Objective
To establish current baseline information for the C aquifer before significant additional groundwater development occurs around the Leupp area, and to continue monitoring for long-term changes in groundwater levels, water use, and water chemistry.
Approach
A monitoring network has been established to collect hydrologic data from the C aquifer. Data are collected that describe the groundwater and surface-water systems. Continuous measurements of groundwater levels are made at 5 observation wells, and quarterly groundwater measurements are made at 12 additional wells. Water-level measurements from an additional 18 wells measured by the Arizona Department of Water Resources and the City of Flagstaff are also included when available. Discharge and water-quality field parameters are collected at springs and along Lower Chevelon Creek, and Lower Clear Creek to continue to document and characterize the quantity and quality of water resources at the western and southern end of the Navajo Nation. Seepage investigations are conducted on lower Clear Creek, lower Chevelon Creek, and the Little Colorado River to evaluate the base flow component of these streams.
Sources/Usage: Public Domain. Visit Media to see details.Approximate extent of the C Aquifer and location of the study area, northeastern Arizona - Publications
Below are publications associated with this project.
Groundwater and surface-water data from the C-aquifer monitoring program, Northeastern Arizona, 2012–2019
The Coconino aquifer (C aquifer) is a regionally extensive multiple-aquifer system supplying water for municipal, agricultural, and industrial use in northeastern Arizona, northwestern New Mexico, and southeastern Utah. This report focuses on the C aquifer in the arid to semi-arid area between St. Johns, Ariz., and Flagstaff, Ariz., along the Interstate-40 corridor where an increase in groundwaterAuthorsCasey J.R. Jones, Michael J. RobinsonGroundwater, surface-water, and water-chemistry data from C-aquifer monitoring program, northeastern Arizona, 2005-11
The C aquifer is a regionally extensive multiple-aquifer system supplying water for municipal, agricultural, and industrial use in northeastern Arizona, northwestern New Mexico, and southeastern Utah. An increase in groundwater withdrawals from the C aquifer coupled with ongoing drought conditions in the study area increase the potential for drawdown within the aquifer. A decrease in the water tabAuthorsChristopher R. Brown, Jamie P. MacyGeologic, hydrologic, and chemical data from the C aquifer near Leupp, Arizona
No abstract available.AuthorsJ.P. Hoffmann, D. J. Bills, J. V. Phillips, K. J. HalfordGeneralized hydrogeology and ground-water budget for the C Aquifer, Little Colorado River Basin and parts of the Verde and Salt River Basins, Arizona and New Mexico
The C aquifer underlies the Little Colorado River Basin and parts of the Verde and Salt River Basins and is named for the primary water-bearing rock unit of the aquifer, the Coconino Sandstone. The areal extent of this aquifer is more than 27,000 square miles. More than 1,000 well and spring sites were identified in the U.S. Geological Survey database for the C aquifer in Arizona and New Mexico. TAuthorsRobert J. Hart, John J. Ward, Donald J. Bills, Marilyn E. Flynn - Web Tools
Below are data or web applications associated with this project.
C-Aquifer Monitoring Program
The Coconino aquifer (C aquifer) supplies water to northeastern Arizona. Proposed increases in groundwater withdrawal to meet population demands, coupled with ongoing drought conditions, increase the potential for water-level changes in the aquifer. The USGS monitors groundwater and surface-water conditions in northeastern Arizona.
- Partners
Below are partners associated with this project.