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  • Writer's pictureMark L. Johnson

Marana Water DAWS Modification-Part I Introduction & DAWS Basics


Marana Water (MW) applied to modify its Designated Assured Water Supply (DAWS) with the Arizona Department of Water Resources (ADWR) on 5/18/22.

ADWR reviewed the application and issued MW a Notice of Deficiency on 10/17/22.

MW responded to the Notice of Deficiency on 1/12/23.

ADWR will now review the Notice of Deficiency response and determine if more information is required and ultimately prepare a draft MW DAWS Modification decision.

Once ADWR publishes its draft decision, the public has very little time to comment. Therefore, the Tortolita Alliance (TA) is providing this three part series (see Parts below) to inform the public well in advance of the ADWR draft decision so you can review the facts and our analysis/conclusions and then make an informed comment to ADWR if so desired.

Part I-DAWS Basics (presented below)

Part II-MW DAWS Modification Analysis (next blog)

Part III-ADWR Draft Decision Analysis and Comment Letter (future blog)

Sadly, the MW DAWS Modification Application and associated information/data is not readily available to the public on the Town of Marana Website and had to be obtained via Public Record Requests (PRRs).

The information/data and analysis presented in this series is based on the MW DAWS Modification Application, Notice of Deficiency and Response To Notice of Deficiency obtained from responses to ADWR PRRs submitted on 9/2/22, 1/18/23 and follow-up questions with ADWR staff.


DAWS Basics

What Is DAWS?

To obtain a Designation of Assured Water Supply (DAWS), a water provider must demonstrate:

  1. Sufficient supplies of adequate quality water are physically, continuously and legally available to meet the estimated demands of the community for a 100-year period.

  2. Meet the goals of Active Management Area (AMA). In the case of the Tucson AMA (TAMA), the primary goal is to achieve safe yield, i.e. water withdrawn from the aquifer(s) must be balanced by water going into the aquifer.

  3. The water provider must demonstrate the financial capability to construct and operate the water system.

What Are The Basic DAWS Steps?

Step 1-Water Demands

Establish Total Water Demands in the study area. Total Water Demands include Existing Water Demands, Issued Water Demands (e.g. DAWS for other water providers) and Application Water Demands (water provider) projected to a specific time in the future (Designation Period).

Step 2-Groundwater Model

Utilize a numerical computer Groundwater Model that simulates local geology, aquifer recharge/discharge, groundwater flow, groundwater elevation, existing and proposed wells and groundwater pumping to meet the Total Water Demands for a period of 100-years.

Step 3-Groundwater Level In 100 Years

The groundwater levels in aquifer(s) cannot exceed 1,000 feet below land surface (bls) at the end of the 100-year period.

Step 4-Sources of Supply

Establish the Sources of Supply that the applicant will utilize to meet the Application Water Demands, e.g. Central Arizona Project (CAP), recycled wastewater (effluent), groundwater, etc.

Step 5-Groundwater Allowance

ADWR calculates a Groundwater Allowance available to the water provider. Any groundwater pumping beyond the Groundwater Allowance must be replenished by a non-groundwater source which is typically provided by and purchased from the Central Arizona Groundwater Replenishment District (CAGRD).

Step 6-Draft DAWS & Comment Period

ADWR will analyze and develop the Designation based on Items 1-5 and issue a draft DAWS for public comment (15 day period after last public notice).

Why Is DAWS Important?

Water is the sustenance of all life. We cannot live without it. Therefore, it is imperative that proper water supply planning is in place. We need to be assured that water will be available for future generations and the environment---not for just 100 years, but forever.

This MW DAWS Modification Application is not only important for MW customers but for other residents of Marana as well. We are one community. This is especially true for Tucson Water (TW) customers in Marana because of the current Tucson Water Service Area Policy adopted by the City of Tucson Mayor and Council and the current Intergovernmental Agreement between the Town of Marana and Tucson Water (click on link below).

Marana-Tucson Water IGA-2020
Download PDF • 11.44MB

MW's Northeast sector (exclusive of the Dove Mountain Specific Plan) covers the entire Tortolita Fan (including the Tortolita Preserve and surrounding lands) and is primarily pristine Sonoran Desert land owned by the Arizona State Land Department. These areas are not in MW's Intended Service Area and there are no planned developments for this area included in the DAWS Application (see map below).

In addition, TW cannot expand water service in the Northeast sector of Marana beyond its existing Obligated Water Service Area (Dove Mountain Specific Plan) which is defined by historical agreements with developers.

Therefore, once the current Dove Mountain Specific Plan development projects (Saguaro Reserve, Boulder Canyon Pass, Tapestry, etc.) are complete, there should be very little future development in the Northeast sector as public water supply is not intended to be available for this area. However, we know from past experience, that we and future generations must vigilant to ensure this area remains protected.


Next up is Part II Marana DAWS Modification Analysis where we will analyze the MW DAWS Modification Application, Notice of Deficiencies and Response and offer some conclusions.


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