Northern Arizona Hydrogeology Some basics Coconino Plateau Hydrogeology Flagstaff and Coconino Plateau Water Resources Well development, City of Flagstaff Effluent discharge to the Rio de Flag from Wildcat WTP Blue Spring, Little 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
Conservation of energy and mass. I.E. no free lunch Safe yield does not exist. At best it is a legal term that describes planned depletion. Dynamic Equilibrium and Water Balance storage Steady State 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. Inflow: Q 0 Pumping: Outflow: Q 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).
40 35 Dry period (1942-63) Annual Precipitation and Annual Average Precipitation, Flagstaff Pulliam Airport Dry period (1970-75) Dry period (1996/97- present) Precipation, inches 30 25 20 15 10 1950-2000 average, 22.6 in. 1950-2013 average, 20.6 in. 5 1950 1960 1970 1980 1990 2000 2010 Year ~120 % normal November 3, 2015
Surface Water, Northern Arizona Lake Mead Lake Powell Havasu Spring Blue Springs Flagstaff Prescott Mormon Pocket Sterling Spring Page Springs Montezuma s Well Fossil Springs Artesian Spring Hugo Meadow Holbrook Perennial stream Intermittent or ephemeral stream Largest Reservoirs in the Continental U.S. One of the largest river systems in the Continental U.S. Few other perennial streams Lake Roosevelt
Ground Water, Northern Arizona Lake Mead Lake Powell Prescott Havasu Spring Mormon Pocket Page Springs Montezuma s Well Fossil Springs Blue Springs Flagstaff Artesian Spring Black Mesa Basin Hugo Meadow Holbrook Several regional aquifers at different depths Many local perched water-bearing zones N aquifer C aquifer R-M aquifer Few large springs represent major discharge zones for regional aquifers 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 Potentiometric surface (water level), in feet above sea level Na-Cl water (Supai origin?) Ca-Mg-HCO3 water (Kaibab origin?) 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
SPRINGS SPRINGS Conceptual model Flow system: Southern Colorado Plateau, NAZ San Francisco Peaks N ET RECHARGE Mesa Butte Fault RECHARGE ET ET RECHARGE ET RUNOFF ET ET S Grand Canyon Lowpermeability rocks Verde Valley
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. From USGS SIR 2005-5222, Hydrogeology of the Coconino Plateau = 8,000 acre-feet -313,000 acre-feet 6,000 acre-feet
76 Figure 6b. 09404115, Havasu Creek above the mouth near Supai, Arizona Dry period (1996/97-present) 27-year mean 30 28 figure 6e. 09503700, Verde River near Paulden, Arizona 50-year mean Dry period (1996/97- present) Winter base flow, ft 3 s 74 72 70 68 5% decline Winter base flow, ft 3 /s 26 24 22 20 18 28% decline (different flow system) 66 2000 2010 16 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 Winter base flow, ft 3 /s 95 90 85 80 75 70 65 50-year mean Dry period (1996/97- present) Winter base flow, ft 3 /s 38 36 34 32 30 28 30-year mean Dry period (1996/97- present) Winter base flow, ft 3 /s 8.5 8.0 7.5 7.0 6.5 50-year mean Dry period (1996/97 -present) 60 55 27% decline 1970 1980 1990 2000 2010 Year 26 24 19% decline 1990 2000 2010 Year 6.0 5.5 21% decline 1970 1990 2010 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 Lake Mary Well Field Red Gap Ranch 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 Normal School to train teachers completed in 1898 to the south of Flagstaff Cline Library Special Collections 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 period (1970-75) Dry period (1996/97- present) Lake Contents, acre-feet 15000 10000 5000 Lake Mary Contents at spillway crest, 16,300 acre-feet 0 1950 1960 1970 1980 1990 2000 2010 Year 63 year average capacity, 7,100 acre-feet (45%) From City of Flagstaff Report to the Water commission, 2015
Observation Wells Lake Mary 1 City of Flagstaff, Continental #2, (A-21-08) 17BCA2 Water level, in feet below land surface 500 600 700 100+ ft decline 800 900 1000 1/1/19501/1/19551/1/19601/1/19651/1/19701/1/19751/1/19801/1/19851/1/19901/1/19951/1/20001/1/20051/1/2010 Year Woody Mountain 5 Water Level (feet below land surface) 1300 1320 1340 1360 1380 1400 1420 1440 1460 1480 1500 1520 1540 1560 1580 1600 1620 1640 1660 1680 1700 1720 1740 1760 2000 2010 Time (year) NPS-Wupatki, Citadel Well (A-25-09) 06CCD 1050 1582 Water level, feet below land surface 1100 1150 1200 1250 1300 1350 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 Water Level (feet below land surface) ~50 ft decline ~2 ft decline 1583 1584 1585 1586 1587 1588 1589 1590 1960 1965 1970 1975 1980 1985 1990 1995 2000 2005 Time (year)
Seismic studies, djbills, USGS 1996, the City, working with USGS, began to explore for sites and develop wells in the Inner City area. By 2012, 7 wells in operation. I-40 well, djbills, USGS
Mountain 12% Stream Source: Report to Water Commission, 2013, p. 17 (1949-2012 average) Conservation and reuse (goal 20%...2014 actual, 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 mi 2, 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 N AZ Regional Ground-Water Flow Model Water-Level Contours for Steady State Conditions Steady-State Ground- Water Altitude Contours - ~300 ft Flagstaff Holbrook Ground-water divide St. Johns 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 Prescott Verde River Snowflake St. Johns Payson
Potential future water demand No data or missing control Williams Flagstaff Big Chino Holbrook Little Chino Sedona Prescott Verde River Snowflake St. Johns Future demand 1,000 ac-ft or greater Payson
C and R-M aquifer BY 2050, THE COCONINO PLATEAU S WATER 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 djbills@usgs.gov (928) 556-7142 http://az.water.usgs.gov/