In 1980, the Arizona Legislature passed landmark water management legislation for the populated areas of central Arizona.  The purpose of these laws was to create sustainable water supplies for citizens of the state through a mix of surface water, groundwater and Colorado River water.  Although Central Yavapai County was included in this legislation, it had virtually no practical hope of accessing Colorado River water because of its location relative to the infrastructure that would deliver these supplies.

The 1980 legislation strictly regulated use of groundwater in regions of the state with a history of groundwater mining, including the Prescott area.  Without an alternate water supply, limitations on the use of groundwater threatened to stifle economic growth in Central Yavapai County.  Recognizing this, the Legislature in 1991 granted the City of Prescott legal access to a limited amount of groundwater in the neighboring Big Chino Sub-basin.  Prescott was singled out in the 1991 legislation for several reasons: it was the only community in Central Yavapai County that operated its own water system; it was the only community with a Colorado River allocation through the CAP; and it was the only community that could assist the state in settling the water claims of the Yavapai-Prescott Indian Tribe to the Verde River.  The Big Chino Sub-basin was a thinly-populated area with considerable water resources that had historically been used for agricultural purposes without significant draw-downs in well levels.  In 1999, when the Arizona Department of Water Resources declared that the PrAMA (covering Central Yavapai County) was no longer in a state of safe yield with regard to  groundwater pumping, the imported supplies from the Big Chino Sub-basin became the means for the PrAMA to stop mining groundwater and reach “Safe Yield” by 2025.

Prescott has spent more than $23 million to purchase the Big Chino Water Ranch located approximately 18 miles northwest of Paulden in the Big Chino Sub-basin.  The Ranch includes 4,582.1 acres of deeded lands and 1,948.6 acres of Arizona State Trust Land.  About the same time, Prescott also entered into an intergovernmental agreement (“IGA”) with the Town of Prescott Valley to share 46% of the costs of the Project in return for an equal percentage of the water that is transported into the PrAMA.  Under the IGA, Prescott would take the lead in developing wells, pipes and pumps needed to transport groundwater from the Big Chino Sub-basin for use inside the PrAMA.  Although the Town of Chino Valley elected not to be an original party to the IGA, Chino Valley can opt-in by sharing in the Project’s costs and water at a later date should it choose to do so.  

Since executing the IGA in 2004, Prescott and Prescott Valley have worked diligently to plan, design, and implement the Big Chino Water Ranch Project. 

The Project is comprised of four major tasks:

1. Big Chino Water Ranch environmental assessment
2. Well field development and Ranch Management Plan
3. Design and construction of transmission pipeline and associated storage and pumping infrastructure
4. Installation of monitoring wells to gauge any impacts of groundwater pumping at the Ranch on adjacent water uses

Project implementation has also been divided into four phases:

A significant aspect of the Project is its location, approximately 20 miles to the northwest of the generally-acknowledged location of the headwaters of the upper Verde River.  Because of concerns that groundwater pumping in the Big Chino Sub-basin might eventually impact the flows of the Verde River, this location was expressly chosen even though it results in the need to construct a longer pipeline (now 30-mile) to deliver the water to storage tanks located in Chino Valley.  The pipeline is currently sized to have capacity to transport as much as 12,400 acre-feet of groundwater annually.

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