Northern Arizona Hydrogeology Some basics Coconino Plateau Hydrogeology Flagstaff and Coconino Plateau Water Resources

Effluent discharge to Well development, the Rio de Flag from Blue Spring, Little City of Flagstaff Wildcat WTP Colorado River Competing water demands as a setup for conflict Nationally and Globally.

 Water rights  surface water vs groundwater  water quality  T&E species  ecosystem needs  export/virtual water use Aquifer System Components  Three basic components  Recharge  Discharge  Storage

 Recharge components  Direct from precipitation  From surface water Storage  Underflow

 Discharge components Storage  Springs and streams (baseflow)  ET  Underflow  Steady-State Condition where Recharge = Discharge Dynamic Equilibrium and Water Balance Conservation of energy and mass. I.E. “no free lunch” Steady State storage “Safe yield ” does not exist. At best it is a legal term that describes planned depletion.

Transient

Sustainable yield meets both human and environmental water demands What happens when groundwater is pumped?

• Depends on: Pumping rate Hydraulic conductivity (transmissivity) of the aquifer Extent of the aquifer

Low Hydraulic Conductivity High Hydraulic Conductivity

Initial development

Stream or spring capture

Stream or spring disconnected from ground water

Distance in feet or miles… effects timing Basic Principles 1. Any sustained pumping less than the basin recharge will eventually be balanced by an increased inflow and (or) decreased outflow. 2. In the basins of the Southwest, almost all of the capture will be in the form of decreased outflow. 3. A groundwater development that stops after a period of time will have the effect of reducing the cumulative volume of outflow (assuming no increased inflow) by the total quantity pumped over the period of active pumping. Q Inflow: 0

Pumping:

Q Outflow: 0

Time Basic Principles 1. Any sustained pumping less than the basin recharge will eventually be balanced by an increased inflow and (or) decreased outflow. 2. In the basins of the Southwest, almost all of the capture will be in the form of decreased outflow. 3. A ground-water development that stops after a period of time will have the effect of reducing the cumulative volume of outflow (assuming no increased inflow) by the total quantity pumped over the period of active pumping. 4. Pumping in a bedrock aquifer can capture recharge from an adjacent basin. Basin 1 Basin 2 Q Water, Northern Arizona

Lake Mead Lake Powell

Flagstaff

Prescott

Verde Valley Holbrook

 Arizona – arid and semi-arid hydrology  Low precipitation  High evaporation and transpiration (plants)  Few perennial streams  Water is primarily stored in the subsurface

Lake Roosevelt Where does the water come from and where does it go? But it’s the same every year right? Precipitation (A) and Temperature (B) change, 1950 to 2013 Flagstaff, Arizona (Hereford, 2014). Annual Precipitation and Annual Average Precipitation, Flagstaff Pulliam Airport 40 Dry period Dry Dry period (1996/97- (1942-63) period present) (1970- 35 75)

30

~120 % normal

25

20

Precipation, inches Precipation, 15

1950-2000

average, 22.6 in.

10 1950 -2013 average, 20.6 in. 5 1950 1960 1970 1980 1990 2000 2010 Year

November 3, 2015 Surface Water, Northern Arizona

Lake Mead Lake Powell

Havasu Spring Blue Springs Flagstaff Mormon Sterling Spring Pocket Prescott Page Springs Montezuma’s Well Artesian Hugo Spring Holbrook Fossil Springs Meadow

 Largest Reservoirs in the Continental U.S. Perennial stream

Intermittent or  One of the largest river systems in ephemeral stream the Continental U.S.  Few other perennial streams

Lake Roosevelt Ground Water, Northern Arizona

Lake Mead Lake Powell

Havasu Blue Springs Spring Black Mesa Flagstaff Mormon Basin Pocket Prescott Page Springs Montezuma’s Well Artesian Hugo Spring Holbrook Fossil Springs Meadow  Several regional aquifers at different depths  Many local “perched” water-bearing zones

N aquifer  Few large springs represent major discharge zones for regional aquifers C aquifer R-M aquifer  Ground-water supports base flow of few perennial streams

Lake Roosevelt Greater than 2,000 mg/L TDS Greater than 500 mg/L TDS

Holbrook

Approximate extent of salt deposits Na-Cl water (Supai origin?) Potentiometric surface (water level), in feet Ca-Mg-HCO3 water (Kaibab origin?) above sea level

Show Low Black Mesa Basin and Arizona Strip Aquifers and Water-Bearing Zones

C aquifer Where does the water go?

Evapotranspiration

Runoff

Ground-water recharge Perched water-bearing zones C aquifer Redwall-Muav aquifer N

Canyon Grand SPRINGS ET

Southern Colorado Colorado Southern Conceptual model Flow system: Flowmodel Conceptual RECHARGE permeability rocks Low

-

Mesa Mesa Butte Fault

RECHARGE San Francisco Peaks SanFrancisco

Plateau, NAZPlateau, ET

ET

RECHARGE

ET

RUNOFF

Verde Valley

ET

SPRINGS ET

S

Improved geologic and structural information leads to a better understanding of the hydrogeologic framework

North South

West East C aquifer occurrence and movement Redwall-Muav aquifer occurrence and movement How much water is there? Conceptual Model, water budget components

Dynamic equilibrium

302,000 acre-feet

8,000 acre-feet

6,000 acre-feet

From USGS SIR 2005-5222, Hydrogeology of the Coconino Plateau Flow systems no longer in equilibrium: withdrawals, drought, changing land use, etc.

=

8,000 acre-feet

-313,000 acre-feet

6,000 acre-feet

From USGS SIR 2005-5222, Hydrogeology of the Coconino Plateau Figure 6b. 09404115, Havasu Creek above the mouth figure 6e. 09503700, Verde River near Paulden, Arizona near Supai, Arizona 30 76 50-year Dry period Dry period (1996/97-present) 27-year mean (1996/97- mean 28 present)

74

/s 26

3

s

3

72 24

22 70 28% decline 20

Winter base flow, ft flow, base Winter Winter base flow, ft (different flow

68 system) 18 5% decline

66 16 2000 2010 1970 1990 2010 Year Year

Figure 6f. 09504000, Verde River near Clarkdale, Arizona Figure 6c. 09504420, Oak Creek at Sedona, Arizona Figure 6d. 09505200, Wet Beaver Creek near Rimrock, Arizona

95 38 8.5 50-year Dry period 30-year Dry period (1996/97- 50-year Dry 90 (1996/97- 36 present) period mean mean 8.0 mean present) (1996/97 85

/s

/s /s -present)

3 34

3

3 7.5 80 32

75 7.0

30 70 6.5 28

Winter base flow, ft base flow, Winter

Winter base flow, ft flow, base Winter Winter base flow, ft Winter base flow, 65

6.0 60 26 27% decline 19% decline 21% decline 55 24 5.5 1970 1980 1990 2000 2010 1990 2000 2010 1970 1990 2010 Year Year Year City of Flagstaff Water Supplies (notice most wells on forest service lands)

 Local Springs

 Inner Basin Wells

 Lake Mary Local Springs

 Woody Mountain Well Field

Red Gap Ranch  Lake Mary Well Field

 Inner City Wells

 Red Gap Ranch?

From City of Flagstaff Report to the Water commission, 2012 Development of water resources on Forest Service lands

Administering National Forest System lands to secure favorable conditions of water flow (Organic Administration Act of 1897)  SPECIAL USE PERMIT  specify that the well be located, constructed, and operated in a manner that would avoid or minimize impacts to the groundwater-dependent ecosystem.  35 gallons per minute or greater would be required to monitor and report groundwater withdrawals  PROPOSED GROUNDWATER DIRECTIVE FSM 25 (May, 2014)  Encourage source water protection and water conservation.  Require the evaluation of potential impacts from groundwater withdrawals on NFS natural resources. Observatory Mesa Note buildings at the base of Observatory Mesa.

 Site of Old Town, Antelope/Old Town Spring  San Francisco spring (MNA)  Leroux springs  O’Neill spring

Cline Library Special Collections Inner Basin Springs and wells

Credit: Jon Mason 1890s construction of pipeline from Inner Basin to Flagstaff

Cline Library Special Collections Normal School to train teachers completed in 1898 to the south of Flagstaff

Lower LM Dam 1905 AZ Lumber and timber Co Upper Lake Mary built by the city in 1941. Crest raised 10 ft. in 1951.

Credit: Don Bills

Capacity of Lake Mary when full 16,300 ac-ft. About a 2-year supply at 2010 water use rates

Lake Mary Contents, 1949 to 2015

20000 Dry period (1942-63) Dry Dry period (1996/97- period present) (1970-75)

Lake Mary Contents at spillway crest, 16,300 acre-feet

15000

10000

Lake Contents, acre-feet 5000

63 year average capacity, 7,100 acre-feet (45%) 0 1950 1960 1970 1980 1990 2000 2010 Year

From City of Flagstaff Report to the Water commission, 2015 Observation Wells

Lake Mary 1 City of Flagstaff, Continental #2, (A-21-08) 17BCA2

500 1300 1320 1340 1360 1380 600 1400 1420 1440 1460 1480 700 1500 100+ ft decline 1520 1540 1560 1580 800 1600 1620 1640 1660 900 1680 1700

Water Level (feet below land surface) land below (feet Level Water 1720 Water level, in feet below land surface Water level, in feet 1740 1760 1000 2000 2010 1/1/19501/1/1955 1/1/1960 1/1/1965 1/1/1970 1/1/1975 1/1/1980 1/1/1985 1/1/1990 1/1/1995 1/1/2000 1/1/2005 1/1/2010 Time (year) Year Woody Mountain 5 NPS-Wupatki, Citadel Well (A-25-09) 06CCD 1582 1050

1583 1100 1584 1150 1585

1200 1586

1250 1587

1588 1300 ~50 ft decline ~2 ft decline

Water Level (feet below land surface) land (feet below Level Water 1589

Water level, below feet land surface 1350 1590 1960 1965 1970 1975 1980 1985 1990 1995 2000 2005 1/1/1960 1/1/1965 1/1/1970 1/1/1975 1/1/1980 1/1/1985 1/1/1990 1/1/1995 1/1/2000 1/1/2005 1/1/2010 Year Time (year) Seismic studies, djbills, USGS

1996, the City, working with USGS, began to explore for sites and I-40 well, djbills, USGS develop wells in the Inner City area. By 2012, 7 wells in operation. Source: Report to Water Commission, 2013, p. 17 Mountain (1949-2012 average) Conservation and reuse (goal 12% 20%...2014 actual, Stream 30%)

40%

Deep Rock 48% Red Gap Ranch: Part of the City’s water future? Northern Arizona Regional Ground-Water Flow Model

Background •Product of the USGS and ADWR Rural Watershed Initiative studies in Northern Arizona. •Addresses the need for a tool that can be used to evaluate regional water supply and demand scenarios on the sustainability of water and environmental resources throughout the region. Objective •Improve understanding of hydrologic processes on a regional scale. •Provide boundary conditions for local, nested models. •Provide a numerical tool to identify data collection needs. •Provide a numerical information tool for management and protection of water resources. Model area is over 26,000 mi2, one of the largest attempted in the country to date (Ogallala and Central Valley in Calif. are bigger) How does a numerical model work?

Darcy’s Law

By Bennett and Giusti 1.—Determine physical characteristics of model domain. 2.—discretionization of model domain into cells and layers. 3.—Application of physical characteristics to cells and layers. 4.—Model calibration and sensitivity analysis. Characterization of model layers based on geology Translate conceptual models to numerical models: Hydrology Steady-State Ground- Water Altitude N AZ Regional Ground-Water Flow Model Contours - ~300 ft Water-Level Contours for Steady State Conditions

Flagstaff

Holbrook St. Johns Ground-water divide

Pre-development, 1910 in this model Water Withdrawals (Average annual pumping rate per decade) No data or missing control

Williams Flagstaff Big Chino Holbrook Little Chino Sedona Verde River Prescott St. Johns Snowflake

Payson Potential future water demand

No data or missing control

Williams Flagstaff Big Chino Holbrook Little Chino Sedona Verde River Prescott St. Johns Snowflake

Future demand 1,000 ac-ft or greater Payson BY 2050, THE COCONINO PLATEAU’S WATER

C and R-M aquifer DEMANDS WILL SIGNIFICANTLY EXCEED SUPPLY

C aquifer *

Non-Tribal demand increases by 14,483 acre-feet by 2050 • City of Flagstaff recently increased its demand estimate from 16,808 at 2050 to 20,000 at 2100

Tribal demand increases by over 100 gallons per capita per day by 2050 (Charts from the North Central Arizona Water Supply Appraisal Study) Use of Regional flow model to test water development scenarios on the Coconino Plateau (Draft-provisional)

 Black dots are simulated wells added to the model in areas where groundwater withdrawals are expected to increase or develop No data, missing control and/or aquifer misrepresented

Different models, different results

Groundwater models are great tools for qualitative and quantitative assessment of aquifers. But… Importance of Monitoring in Quantitative Assessments of Stream Flow and Groundwater Flow

 Long-term monitoring  Base flow  Spring discharge  water levels  Withdrawal rates Green dots and triangles only actively monitored sites…Is it enough? Comments, questions, contact info

Donald Bills [email protected] (928) 556-7142 http://az.water.usgs.gov/