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  • Writer's pictureMark L. Johnson

Water Woes XXX-Open House-Supply v Demand-Population



 



Marana Water Open House


Marana Water held an Open House on Wednesday (5/29/24). It included four presentations; (1) Marana Water Overview, (2) Marana Water-Designation of Assured Water Supply (DAWS), (3) Tucson Water (Marana Service Area) Overview and (4) Cortaro Marana Irrigation District (CMID) Overview. There was a break-out session after the presentations whereby attendees could ask questions.


The PowerPoint Slides (just click and download) for each presentation are located below. The PowerPoint Slides including the lead graphic were provided by Marana Water. At the end of the PowerPoint Slides is a list of important questions posed by TA along with the answers from the presenters.


First, let's take a look at the key information gleaned from this Open House including; Supply versus Demand, Population Projections and Other Key Takeaways.


 

Supply versus Demand



The chart above depicts Marana Water Supply versus Demand based on the recently approved DAWS Modification and other information presented at the Open House. This chart is presented in a slightly different form than similar charts in the PowerPoint Slides to make the data completely consistent with the approved DAWS Modification and the 2020 Census. Here are the key points:


  • Marana Water Total Demand will increase from 2,974 acre-feet per year (AFY) (2022) to 8,870 AFY (2032) for an increase of 5,896 AFY. This is a 12% annual growth rate.

  • Marana Water existing permanent sources of supply (CAP Colorado River Water, Wastewater Treatment Effluent and Long Term Storage Credits (LTSCs)) total 4,313 AFY and are completely used by demand on an annual basis starting in 2024.

  • Beyond 2024 (unless other permanent sources of supply are secured) the extra source of supply will be Groundwater which has to be replenished by the Central Arizona Groundwater Replenishment District (CAGRD). See Question 4 below.

  • Committed Demand (already approved & platted lots) will start being supplied by Groundwater beginning in 2024.

  • Projected Demand will start being supplied by Groundwater beginning in 2026. This is demand from lots already approved by the Planning Commission & Town Council but have not been platted. Remember TA reported in Water Woes XIV-Pause on DAWS that Marana has already approved 17,228 un-platted lots which is equivalent to 6,227 AFY!

  • At the end of the DAWS 10-year approval period (2032) only 8,870 AFY of actual Service Area Demand is expected. This means that 6,665 AFY of DAWS approved Groundwater (replenished by CAGRD) will be available for future platted subdivsions. It is not known exactly when this will occur and Marana Water will have to apply for another DAWS Modification by the end of the 10-year period.


Population Projections



The Marana Populations Projections Chart (above) shows the total Marana population based on water demand projections for Marana Water (DAWS Data) and Tuscon Water-Marana (One Water 2100 Data) and using 3.0 persons/EDU or Lot. Here are the key points from this chart:


  • Marana Water Service Area population grows by 215% from 22,600 (2022) to 71,100 (2032) for an increase of 48,500 which is a 12.2% annual growth rate.

  • Tucson Water Service Area population grows from 30,400 (2022) to 33,200 (2032) for an increase of 2,800 which is a 0.90% annual growth rate. This confirms that the Tucson Water Service Area in Marana cannot be expanded. See Question 5 below.

  • The Total Marana Population doubles from 53,000 (2022) to 104,300 (2032) for an increase of 51,300.

  • Sometime after 2032, if Marana Water utilizes the remaining DAWS approved 6,665 AFY mentioned above, the Total Marana Population will more than triple and reach 171,000.


Can Marana provide the infrastructure and services necessary to support this tremendous growth? How will this growth impact the taxes we pay?


 

Other Key Takeaways


This was a good meeting from the following perspectives:


  • Important information regarding Marana Water issues is now being shared openly with the public with the opportunity to ask questions.

    • For example, another Open House is planned to review the Water Rate Study.

    • Marana Water should make much of this information readily available on the Marana Water website.

  • Local water utilities appear to be working together on water supply and water quality issues which is a pleasant departure from the typical parochial nature of water utilities.

  • Although Marana DAWS has doubled, there is recognition that water supply issues still exist. For example:

    • Colorado River system is over-allocated and supply contract cuts are possible.

    • Reduction of the heavy (72%) reliance on groundwater (must be replenished by CAGRD). Two projects are proposed to potentially reduce this to 30%. See Question 4 below.


 

Open House PowerPoint Slides


Marana Water Overview-Jing Luo-Water Director


Marana Water Open House-MW Overview-5-29
.pdf
Download PDF • 5.11MB


Marana Water-DAWS-Asia Philbin


Marana Water Open House-DAWS-5-29-24
.pdf
Download PDF • 3.89MB


Tucson Water Overview-Scott Schladweiler


Marana Water Open House-Tucson Water Overview-5-29-24
.pdf
Download PDF • 5.99MB


Cortaro-Marana Irrigation District (CMID) Overview-Doug Greenland


Marana Water Open House-CMID Overview-5-29-24
.pdf
Download PDF • 4.56MB


 

Questions & Answers


Q1. Isn't the 12,000 acre-feet (AF) of Long Term Storage Credits (LTSCs) obtained from the Tohono O'Odham Nation a one time purchase?


A1. Yes, over the 100-year DAWS analysis period that equates to 120 AF per year (AFY).

 

Q2. Where is the source of the PFAS and 1,4-Dioxane (forever chemicals) aquifer contamination?


A2. The primary source is the area near the Tucson Airport. However, it is theorized that the forever chemicals could also be in the effluent of local wastewater treatment plants which is making its way into the aquifer(s).

 

Q3. Has legal action been taken with the potential forever chemical polluters?


A3. Yes.

 

Q4. The recently approved DAWS Modification indicates that 72% of Marana Water's future source of supply portfolio is groundwater the must be replenished by CAGRD. Only 50% of CAGRD sources of supply are permanent and many come from the Colorado River which could be subject to future cuts. Has CAGRD provided the specific sources of supply they intend to meet the Marana Water replenishment needs?


A4. Not yet but two projects have been identified that could reduce the 72% CAGRD groundwater replenishment requirement to 30%. The two projects are; (1) Santa Cruz River Effluent (withdrawal of Santa Cruz River water which is sourced from various upstream wastewater treatment plant discharges) and (2) CMID lease/purchase excess water rights. No details regarding these two potential projects were available. Information regarding these two projects should be shared with the community on the Marana Water website.


 

Q5. Isn't it true that Tucson Water cannot extend its service area beyond existing legacy contracted service areas, e.g., Dove Mountain Specific Plan area, due to Tucson Water's Service Area Policy?


A5. Yes.

 

Q6. Global Water Resources, Inc. has recently purchased and is planning to purchase more of Tucson Water's small isolated water systems. Has Marana Water considered selling some of its small isolated water systems to avoid the huge cost of integration?


A6. No.

 

Q7. Is CMID required to replenish the water removed from the aquifer via its 44 wells?


A7. No, because these wells have been utilized for agricultural purposes for many years and grandfathered, i.e. not subject to Groundwater Management Act replenishment requirements.


 

Q8. The DAWS groundwater modeling rules do not require simulating recharge in the Impact Area. Wouldn't it be more accurate to simulate recharge in the Impact Area to determine exactly how much replenishment water is required and if it is physically feasible to replenish that amount of water?


A8. Although not required as part of the DAWS groundwater modeling analysis, including all the aquifer recharge inputs would provide a more complete picture.



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