"Maintaining a sustainable water supply for present and future generations."

The Santa Cruz Active Management Area (AMA) covers 716 square miles in the Upper Santa Cruz Valley River Basin. It is principally concentrated around a 45 mile reach of the Santa Cruz River from the international border to the Continental gaging station, a few miles north of the Santa Cruz/Pima County line. Along this reach, the river is characterized as an intermittent desert stream that contains uninterrupted perennial and effluent dominated reaches. The drainage area of the Santa Cruz River upstream from Continental is about 1,680 square miles. From its headwaters in the San Rafael Valley, the river flows southward approximately 9 miles and enters Mexico. During its 35 mile course through Mexico, the river continues its southward flow for a short distance and then bends northward and enters Arizona 5 miles east of Nogales. Within the United States, the Santa Cruz River continues northward for 65 miles from Nogales to Tucson, where it continues beyond to the confluence of the Gila River. (Chapter II TMP for overview of AMA water resources. )

Analysis of Historic Water Level Data Related to Proposed Assured Water Supply Physical Availability Criteria for the Santa Cruz Active Management Area Santa Cruz and Pima County, Arizona – Modeling Report No. 18. - Proposed new groundwater withdrawals for Assured Water Supply (AWS) purposes in the Santa Cruz AMA must be consistent with the AMA’s dual water management goals of maintaining safe-yield and preventing local water tables from experiencing long-term declines (A.R.S. 45.562.C).

This report model 18 (1.14MB) presents an analysis of available groundwater level data for the Santa Cruz AMA. The analysis includes the calculation of average historical water levels and standard deviations that will be used to evaluate the potential impacts of proposed new AWS withdrawals.

Santa Cruz AMA Groundwater Flow Model - Modeling Report No. 14 - The Arizona Department of Water Resources has developed a regional groundwater flow model of the Santa Cruz Active Management Area that covers a reach of the effluent-dominated Santa Cruz River in southern Arizona.

The model_14 (5.4MB) was developed as a tool to better understand the complex and interdependent stream-aquifer system, and to provide guidance for the management of regional water resources. Water management topics relevant to the Santa Cruz AMA include bi-national water issues and the reliability of water supplies.

Santa Cruz AMA Groundwater Flow Model – Modeling Report No. 15 -The Arizona Department of Water Resources has developed a regional groundwater flow model of the Santa Cruz Active Management Area that covers the “Microbasin” reach of the Santa Cruz River in southern Arizona from the International Boundary to the Nogales International Wastewater Treatment Plant.

The model_15 (5MB) was developed as a tool to better understand the complex and interdependent stream-aquifer system, and to provide guidance for the management of regional water resources. Water management topics relevant to the Santa Cruz AMA include bi-national water issues and the reliability of water supplies.

To meet the AMA goals, new uses of water within certain areas of the Santa Cruz AMA will need to be offset either by replenishment of water withdrawn or through a corresponding reduction in water use by existing users. Replenishment could be through some mechanism to purchase recharge credits or in some circumstances by a demonstration that water pumped out of storage will be naturally recharged. Reduction in existing use could be achieved by discontinuing existing water use in the same local areas in which a new demand begins. Water that is conserved through increased efficiency could, in part, be taken up by a new use.

Coordinated Management of Surface and Groundwater

The legislature has mandated that management of groundwater and surface water rights be coordinated in order to achieve the AMA goals. This will likely result in a high degree of water management awareness by the local water right holders in the Santa Cruz AMA. To successfully manage water supplies for the Santa Cruz AMA, groundwater programs cannot be implemented without examining the consequences to surface water rights, and surface water rights cannot be obtained or altered without examining the consequences to groundwater programs and overall water management efforts and the public interest.

Although the laws governing surface water and groundwater are distinct, they are not necessarily at cross-purposes. An effective coordinated management of surface and groundwater must provide the mechanisms to protect the water rights held under both legal authorities.

International Water Issues

The international nature of the Santa Cruz AMA water resources requires binational coordination of water management efforts. The Santa Cruz River is one of the main water supply sources for Nogales, Sonora and for Nogales, Arizona. The water management policies of Nogales, Sonora, in regard to the use of the Santa Cruz River, may have a direct impact on the volume of water entering the Santa Cruz AMA. Additional pumping of Nogales, Sonora Santa Cruz River well fields could reduce both small flood flows and sub-flow, thereby reducing the recharge in the Santa Cruz AMA.

Development Pressure

The City of Nogales and Rio Rico are the two biggest water users in the municipal sector. They have been growing at the rate of 5 to 8 percent per year for the last 10 years. If this rate of growth continues creative water management policies will be required to maintain the AMA goals and meet the new water needs.

Greater development pressure may be coming from the north. Expansion of existing development in the Green Valley area is headed south. This development is already at the northern boundary of the Santa Cruz AMA and is expected to continue.

Development of Technical Data and Tools

The Department continues to devote considerable resources to the development of the groundwater flow model for the AMA. Due to its complicated nature, a considerable amount of detail is necessary to accurately simulate the hydrologic system. This work will help in conceptually understanding some of the relationships between the Younger and the Older Alluvium.

Development of Assured Water Supply Criteria

A major work effort is being done to establish the assured water supply criteria for evaluating the statutory requirement that issuance of an assured water supply must be consistent with the AMA goals. In order to develop the appropriate criteria, it is necessary to have: (1) a better understanding of the impact of diversions at specific locations of the subflow water levels; (2) a better understanding of the impact of the effluent introduced into the system and its long-term availability; (3) a better understanding of how effluent, surface water flows, and mountain front recharge affect Younger Alluvium water levels; and (4) a formal determination of nature, validity, and priority of surface water rights in the context of their usage in supporting an assured water supply determination.

The Department is in the process of drafting rule criteria for the AMA. Final adoption of these rules will reflect community and stakeholder input to the highest degree possible

Augmentation/Recharge Limitations

The hydrogeologic characteristics of the aquifers in the Santa Cruz AMA and their close relationship with surface water flow presents a challenge to augmentation and recharge that needs to be addressed with innovative approaches. Effluent discharge from the NIWWTP is a major source of recharge in the AMA, and it is a significant source of water available to support future assured water supply determinations. Additionally, the effluent plays a major role in maintaining water tables and riparian habitat in the Younger Alluvium downstream of the NIWWTP.

Santa Cruz AMA Links

Santa Cruz AMA virtual tour  - (4.4 MB) PowerPoint 97® (This file may take several minutes to download.)

Legislature

City of Nogales (Link coming soon.)

Santa Cruz County (Link coming soon.)

Water Quality (ADEQ)

Adjudication Court

National Water Commission (Mexico)

COPAES (State of Sonora Water Agency)

Santa Cruz AMA Groundwater Users Advisory Council (GUAC) (Link coming soon.)

Santa Cruz AMA Third Management Plan

Santa Cruz AMA Third Management Plan Modifications

Santa Cruz AMA Water Facts (Link coming soon.)

FAQs on Annual Reports (Link coming soon.)

Permit Application Forms (Link coming soon.)

Low Water Use Plant List

Well Information Links

Drilling a Well in Arizona

How to obtain well information (Link coming soon.)

FORTIS-Imaged Well Documents

Wells-55-Search for Wells (Link coming soon.)

Local Well Drillers and Pump Contractors

Surface Water Adjudication

Find Your Watershed (Link coming soon.)

Download Forms (Link coming soon.)

Frequently Asked Surface Water Questions (Link coming soon.)

Santa Cruz AMA Contact Information

Upcoming Meetings (Link coming soon.)

See the Contact Us page for a Mapquest map of the Santa Cruz AMA office.

Images around Santa Cruz AMA

Click on the images below for a large view.

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