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"Conserving and sustaining all water resources...it's our
future."
Contact the Prescott AMA Section
2200 E Hillsdale Road
Prescott, AZ 86301
(928) 778-7202
Prescott AMA Mission
Achieving safe-yield through the promotion of conservation
and the development and utilization of renewable water sources.
Prescott AMA Goal
The Prescott AMA has a statutory goal of
achieving safe-yield by 2025. Safe-Yield is a groundwater management goal which
attempts to achieve and thereafter maintain a long-term balance between
the amount of groundwater withdrawn in an active management area and the annual
amount of natural and artificial recharge in the active management area A.R.S. §
45-561(12). The safe-yield goal is a basin-wide balance. Recharging water in one
part of the AMA can offset groundwater level declines in another portion of the
AMA.
Prescott AMA Quarterly Newsletter
In March 2007, Prescott Active Management Area staff began publishing a quarterly
newsletter.
The newsletter highlights water-related information as it pertains to the Prescott AMA region.
AMA Staff look forward to receiving comments and ideas from the public on newsletter content.
Please
with ideas. Below are links to the newsletter. We hope you find it informative and useful.
March 2007: Project WET Facilitators, Get to Know... The Prescott AMA, Local Drought Impact Group 
June 2007: Patch the Pipe, Get to Know... Mark Holmes, Jim Holt Appointed to GUAC, Rinse Smart in Prescott Valley
September 2007: 2006 Annual Water Use Summary, Get to Know... Jeff Schalau, Compliance, Water Education Materials Available
December 2007: The Year in Review, Legislative Changes, Get to Know... Daniel Timmons, Prescott Valley Effluent Auction, New AMA Program
March 2008: Is the Drought Over? Get to Know… John Rasmussen, Smart Landscapes Use Less Water, Finding Less-thirsty Plants
Prescott AMA Description
 The
Prescott AMA covers 485 square miles in central Yavapai County. The AMA lies
within the Central Highlands physiographic province and is typified by gently
rolling topography with broad sloping alluvial basins and fault block mountains.
Elevations range from about 4,400 feet above sea level in the valleys to about
7,800 feet above mean sea level in the Bradshaw Mountains. Native vegetation
varies from high desert grassland in the basin areas to coniferous forest in the
surrounding mountains. The AMA boundary is defined by the Bradshaw Mountains to
the south, Granite Mountain and Sullivan Buttes to the west, and by the Black
Hills to the northeast.
(Click on images to enlarge.)
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View of Prescott, Granite Dells,
and Watson and Willow Lake. |
The AMA consists of two sub-basins, the Little Chino (LIC) and
the Upper Agua Fria (UAF), which are bisected by a surface drainage divide.
Granite Creek, Big Draw, and Little Chino Creek drain the LIC sub-basin into the
Verde River. Lynx Creek and other smaller ephemeral streams drain the UAF
sub-basin into the Agua Fria River. The LIC sub-basin encompasses western and
northern portions of the AMA, while the UAF sub-basin spans the southeast
portion of the AMA.
Final Determination on the Safe Yield Status of the Prescott
AMA
The Prescott AMA is unique among the three safe-yield AMAs.
During the early 1990s, when the Department was developing the Assured Water
Supply (AWS Rules), there was insufficient hydrologic data at that time to make
a definite determination as to whether the Prescott AMA was at safe-yield or
mining groundwater. Due to this uncertainty the AWS Rules, adopted in 1995,
established a monitoring requirement that specified that the Prescott AMA would
be determined to be out of safe-yield after 3 consecutive years of data that
demonstrated declining water levels and increasing demand for groundwater.
On August 28, 1998, the Director of the Department made a preliminary
determination that the Prescott AMA was not at safe-yield and in an overdraft
condition. This determination was based on data collected by the Department that
demonstrated ongoing groundwater level declines and that existing groundwater
pumping greatly exceeded the AMAs safe-yield goal. In the preceding five years,
water levels in the Prescott AMA declined in more than 73 percent of monitored
wells. Data demonstrated that the Prescott AMA had been out of safe-yield since
at least 1990. After a public hearing and considering public comments and the
analysis of an independent evaluation of the Department’s hydrologic studies,
the Department made a final determination on January 12, 1999 that the Prescott
AMA was no longer at safe-yield. A detailed discussion of the Prescott AMA's
safe-yield status and current hydrologic conditions are presented the
2003-2004 Prescott Active Management Hydrologic Monitoring Report.
Prescott AMA Monitoring Program
Groundwater conditions are monitored in the Prescott AMA with one of the most comprehensive groundwater monitoring programs
in the State. Hydrologic monitoring data and related information are compiled by
the ADWR and are presented in hydrologic monitoring reports. The
measurement of water levels is an important data collection activity that
provides information about changing groundwater storage conditions in the
regional aquifer system. In general, rising water levels are indicators of
increasing groundwater storage conditions, while declining water levels are
indicators of decreasing groundwater storage.
(Click on images to enlarge.)
The report includes water level measurement data collected at 126 well sites.
Decreasing groundwater storage trends were observed at a majority of the 105
wells that were measured in both 2003 and 2004 and that were used for
statistical analysis. Increasing groundwater storage trends were observed in 10
of the 105 wells (10 percent) that were used for statistical analysis.
Changes in
measured water levels from 2003 to 2004 are
shown on Figure 1.
The report provides
compilations of surface water, precipitation, pumpage and recharge data. The
report also presents a conceptual water budget for the Prescott AMA for calendar
year 2003.
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ADWR drilling a new deep monitoring well. |
The report provides the ADWR with an excellent opportunity to
keep water users posted on current hydrologic conditions and data collection and
data analysis activities that support the water management goals of the AMA.
This
report may be downloaded as a PDF file from ADWR’s website.
Prescott AMA Water Budget
A
conceptual water budget
was prepared from the
assembled 2003 pumpage, recharge and surface water discharge data. Estimates of
long-term natural recharge that have been developed from the Prescott model
update are used for that water budget component. The 2003 conceptual water
budget for the Prescott AMA, which is summarized in the 2003-2004 Hydrologic
Monitoring Report, indicates that groundwater outflows exceeded inflows,
resulting in a 11,300 acre-foot overdraft for the year.
Prescott AMA Groundwater Flow Model
The Department of Water Resources
developed a regional groundwater flow model to quantify the impacts of
groundwater pumpage and recharge in the Prescott Active Management Area. The
model was updated in 2002 with new hydrogeologic data and revised estimates of
historical water-use and recharge.
This report may be downloaded as a PDF file from
ADWR’s website .
The model was further updated in 2006 with new hydrogeologic data and an
expanded model area.
Access that report here.
Prescott AMA Issues
There are many important issues facing the Prescott AMA, most
of which involve the increasing demand for groundwater due to continued growth
in the area and the Department’s statutory responsibility to reach safe-yield by
2025. Some of these issues include:
- Augmentation and Recharge Augmentation, as defined by the 1980
Groundwater Code, means "to supplement the water supply of an active
management area and may include the importation of water into the active
management area, storage of water or artificial groundwater recharge." The
Prescott AMA Second Management Plan illustrated the fact that even with
maximum reuse of effluent, demands would outstrip supplies through the year
2025. Therefore, the need for other augmentation measures to supplement
existing groundwater supplies is paramount.
- Recharge/Reuse Projects Treated effluent can be used directly or
recharged into the aquifer. However, due to the small size of the AMA, the
geology that exists within the AMA, and the location of wastewater treatment
plants relative to the areas where recharge projects would be the most
successful, the potential number of locations for viable recharge projects
within the AMA is limited. The future location of regional artificial recharge
facility will therefore require very careful analysis.
- Big Chino Groundwater
A
USGS study
 released in December 2005
underlined the importance of the Big Chino aquifer as a source of the flow of
the Verde River.
The study:
- estimates that 80 percent to 86 percent of the upper Verde River's flow
comes from the Big Chino aquifer
- 14 percent comes from the Little Chino aquifer
- less than six percent comes from an aquifer in the Drake area just north
of the Big Chino
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Irrigated farm land west of
Paulden in Big Chino Subbasin. |
Groundwater importation from the Big Chino subbasin of the Verde River
Groundwater Basin, northwest of the AMA, which is allowable under state
statute, represents the largest source of alternative water supply currently
available for municipal water users within the Prescott AMA. Issues related to
the potential use of Big Chino groundwater involve the concern that downstream
Verde Valley water users would be negatively impacted. The Endangered Species
Act could also impact any transfers. The amount and potential use of Big Chino
groundwater by entities other than the City of Prescott needs to be clarified.
- Surface Water
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Del Rio Springs |
The City of Prescott purchased the Chino Valley Irrigation District’s (CVID)
rights to surface water impounded at Watson Lake and Willow Creek reservoirs.
Under this agreement, the City of Prescott acquired ownership of the dams, the
reservoirs, and through a sever and transfer action facilitated by the
Department, acquired the storage rights on approximately 11,000 acre-feet
annually of surface water flows. The City will maintain the lakes for
recreational uses and will release approximately 1,500 acre-feet per year for
recharge at their recharge facility. Most of those CVID surface right holders
also extinguished their groundwater rights and conveyed them to the City of
Prescott in exchange for municipal and industrial water.
- Water Quality In general, water quality throughout the AMA is
excellent. Radon levels that exceed standards have been detected in granitic
formations around Prescott. The proposed federal maximum contaminant level (MCL)
for radon may force domestic wells situated in hardrock areas to start
receiving water from large providers.
- Exempt Well Issues More exempt wells are drilled in Yavapai County
that any of the other Arizona counties. Currently over 30% of all the new
wells drilled in Arizona are in Yavapai County. Within Yavapai County the
concentration of these wells is within the Prescott AMA. As of August
2005, there were just over 11,200 registered wells in the Prescott AMA. While
some of these wells are drilled in dry lot subdivisions, requiring hydrologic
analysis, many are drilled on lots created through lot splits, for which no
hydrologic analysis is conducted. Issues related to new exempt wells include
well driller compliance, identification of concentrated areas where wells are
required to be deepened or replaced, septic setback compliance and inspection
alternatives, and second exempt wells on the same parcel.
- Septic Systems Groundwater aquifers may potentially be impacted by
nitrate and bacterial contamination due to septic tanks, forcing domestic well
owners to connect with water providers. Although most portions of the AMA are
not subject to this threat, areas where the depth to water is shallow could be
at some risk, particularly where municipal growth rates are high. A large
portion of the exempt wells and dry-lot subdivisions in the Prescott AMA use
septic systems for wastewater disposal, rather than utilizing a central
wastewater collection and treatment system.
- Declining Water Levels Water levels continue to decline in many
areas of the AMA due to the combined effects of a long-term drought and the
increase in pumping from new wells. An increasing number of homeowners are
deepening or replacing domestic exempt wells: a costly and frustrating
experience.
- Changing Water Demand by Sectors Future water management in the
Prescott AMA will need to consider the changing sector proportions of the
overall AMA demand for groundwater. Changes in demand are occurring in each
sector of use and are impacting the supply. The demand for water by the
agricultural sector is expected to continue to decline over the next ten years
at an accelerated rate. However, the cities and towns in the AMA are
experiencing rapid growth.
Links
ADWR Links
Prescott AMA Links
Well Information Links
Links to Records, Permits and Forms
See the
Contact Us page for a map link to the Prescott AMA Office.
Click here to see more images from around the Prescott AMA.
Prescott
AMA Staff Responsibilities
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Prescott AMA Staff |
Areas of Responsibility |
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Area Director |
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Conservation, Low Water Use Plant List, Assured Water Supply,
Recharge and Recovery, Website
Development, Outreach and Education, Public Assistance |
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Administrative Assistant, Groundwater Users
Advisory Council Administration, Well Inquiries, Public
Assistance |
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Groundwater
Rights, Conveyances and Extinguishments, Adjudication/SOCs,
Special Use Permits, Historically Irrigated Acres, Compliance,
Outreach and Education, Service Areas, Public Assistance |
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Municipal Planning, Annual Withdrawal and Use
Reports, Compliance, Water Budgets, Safe-Yield Technical
Advisory Committee, Public Assistance |
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