Know Your H2O-Part X-Marana Water & Tucson Water

Updated: Jul 19

Part X covers Marana Water and Tucson Water including; (1) Town of Marana Joint Service Areas, (2) Marana Water and (3) Tucson Water.


Sections 2 & 3 each have the following subsections; (A) General Description, (B) Groundwater Allowance, (C) Designated Assured Water Supply (DAWS), (D) Water Master Plan (E) Central Arizona Groundwater Replenishment District (CAGRD) Agreement (F) Groundwater Storage and Recovery Facilities and Arizona Water Banking Authority (AWBA) (G) Long Term Storage Credits (LTSCs) & Extinguishable Groundwater Rights, (H) Regional Recharge, Recovery & Delivery Projects (I) Groundwater Pollution & Treatment.


Part X is long and dives deep into the complex world of water supply in Arizona. You may want to first go to the end and read the Conclusions and then come back, take your time and go through each section. I wish there was a better way but the details had to be researched (months) and sorted out in order to untangle this mess and get to the true facts.


Many common water resource terms will be explained but you can go to the Water Lingo Tab for more details.

Notes[1] containing other references and supplemental information are provided at the end of the blog.

Marana Water & Tucson Water




1.0 Town of Marana Joint Service Areas


If you live in Marana your potable water service is provided by either Marana Water or Tucson Water.


The Water Services Areas map above is taken from the Marana Water Website and shows the following service areas within the Town of Marana (Marana): Marana Water Existing (Dark Blue), Marana Water Intended (Light Blue), Tucson Water (Hatched Red) and Tucson Water Contracted [w/developers] (Cross-Hatched Red/Blue).


In 2016, Marana Water and Tucson Water entered into an updated Intergovernmental Agreement (IGA) that defines the areas that Tucson Water could serve within Marana town boundaries. The only areas that Tucson Water could serve are the areas noted above. Apparently, Marana Water and Tucson Water are currently re-negotiating the IGA, which we will watch carefully.


Tucson Water adopted its Tucson Water Service Area Policy on 8/4/10 with amendments on 8/9/11 and 7/9/13. The policy breaks down the Tucson region into Existing Obligated Service Area, Expansion Area, Non-Expansion Area and Unresolved Area. See map in the Tucson Water section below. The Town of Marana is a Non-Expansion Area. Dove Mountain and a few smaller areas are currently served by Tucson Water via developer Contract and cannot be expanded. To serve a Non-Expansion Area the development must be surrounded on three sides by Tucson Water service parcels and contain less than 20 acres of developable land (residential). The policy does allow agreements with other water utilities to wheel other jurisdication's renewable water supplies through Tucson Water infrastructure.


Tucson Water cannot serve the Tortolita Preserve and surrounding Arizona State Lands.


Marana Water apparently does not intend to provide water service to the Tortolita Preserve and surrounding State Lands (white areas) based on the above map colorings.


2.0 Marana Water


A. General Description


Marana Water was established in 1997 with 500 customers. There are seven separate and isolated water systems (North Marana, Picture Rocks, Twin Peaks, Airline/Lambert, Palo Verde, Airport and Falstaff). Each system has it is own wells and water distribution system infrastructure. The source for all wells is the Avra Valley Sub-basin.


Marana Water intends to interconnect these systems over time. The interconnection between Twin Peaks and Picture Rocks system is currently under design.


The following basic statistics are taken from Marana Water 2019 Annual Report [1] to the Arizona Department of Water Resources (ADWR) and input from Marana Water staff:

  • Customers-8,185

  • Population Served-22,100

  • Wells-29 with 21 active

  • Water Recharged-3,121 acre-feet

  • Annual Production-2,470 acre-feet

  • Water Delivered-2,366 acre-feet

  • Average Daily Demand (Delivered)-2.1 million gallons per day

  • Gallons Per Capita Per Day (Delivered)-95.6 gpcd (using 2.7 persons per customer)

  • Miles of Water Main-170 miles

  • Pump Stations-22

  • Storage Reservoirs-22

Marana Water has a very small non-potable water system (115 AFY) in North Marana which is proposed to be transferred to the Cortaro-Marana Irrigation District (CMID). The CMID non-potable water system provides well and/or CAP water for subdivision and park plant/tree irrigation. CMID non-potable demand was 300 AF in 2019.


B. Groundwater Allowance


Each designated water utility within the Tucson Active Management Area (TAMA) is assigned a Groundwater Allowance if the water utility was in existence prior to 2/7/95. The formula per AAC-Title 12-Chapter 15-Section 726 is 15 times volume of water provided to its customers in calendar year 1994.



Each year the Groundwater Allowance is adjusted for any groundwater utilized in this account. For example, Marana Water's beginning balance in 2019 was 3,317.18 AF and 180.7 AF of groundwater was withdrawn leaving 3,136.48 in the Groundwater Allowance Account. See CAGRD-2019 Annual Report above.


The Groundwater Allowance account can be increased by adding Groundwater Extinguishment Credits (see below).


When the Groundwater Allowance account goes to zero, all groundwater water withdrawn must come from non-groundwater supplies, i.e. CAP or Effluent (recycled or reclaimed wastewater).


To put this into perspective, Marana Water's Groundwater Allowance is only equivalent to 1.3 years of current production!



C. Designated Assured Water Supply (DAWS)


Arizona water utilities must have a Designated Assured Water Supply (DAWS) approval from Arizona Department of Water Resources (ADWR). Marana Water most recent DAWS (2033) was approved by ADWR on 1/9/18.


DAWS has three parts; (1) Estimated Demand, (2) Assured Water Supply Analysis and (3) Designation.


Estimated Demand is typically established 10-15 years (Year X) from the application date and is the sum of Current Demand (Year 0), Projected Demand (Year 1-X) and Committed Demand (based on un-platted lots in Year 0).


Marana Water's 2033 Estimated Demand is 7,580 AFY. The figure to the right shows the components.



Assured Water Supply Analysis is the sum of Groundwater, CAP, Effluent and Long Term Storage Credits (LTSCs) available in Year X. CAP, Effluent and LTSCs are contractable items. Groundwater is determined as described below.


Marana Water's 2033 Assured Water Supply is also 7,580 AFY. The figure to the left shows the Components



The Groundwater Component is typically calculated using the following formula:


Groundwater Component = Groundwater Allowance + Incidental Recharge + CAGRD Contract Excess Groundwater + Remediation Water


For Marana Water's 2016 DAWS application this was calculated as:


Groundwater Component = 25.46 + 294.46 + 0 + 0 = 319.82 AFY


Then, the Marana Water DAWS approval magically states that the groundwater component is 3,394.39 AFY because Marana Water demonstrated that amount of groundwater will be available for 100-years. Wow, how did they get there?


After considerable research, it was determined that the Groundwater Component of 3,394.39 AFY came from a hydrology study performed by Clear Creek Associates (Marana Water Consultant) for the 2007 DAWS approval. This study utilized the numerical groundwater model developed for TAMA and applied it to simulate water withdrawals in the Marana Water system including a 2-mile buffer outside the Marana Water service areas.


The following simulations were performed:

  • #1-2005-2016-6,000 AFY Groundwater Withdrawal-Static Water Table Drops (0-150 feet)

  • #2-2005-2116-35,000 AFY Groundwater Withdrawal-Static Water Table Drops (150-300 feet)

  • #3-2005-2116-120,257 AFY Groundwater Withdrawal-Static Water Table Drops To 1,100 feet BLS

The groundwater modeling is flawed in several respects:

  • ADWR regulations require the modeling to show how much groundwater can be pumped over a 100-year period and not lower the water table 1,000' below ground surface. In other words, how much groundwater can be pumped to suck the aquifer dry! This is convoluted. The modeling should demonstrate how much groundwater can be pumped over a 100-year period and maintain safe yield and reduce/eliminate accumulated overdraft.

  • The model utilized only a portion of the TAMA model by installing artificial groundwater barriers and did not account for artificial recharge. The model should encompass the entire sub-basin and include all current inflows and outflows.

The Designation is the official approval from ADWR and states that Marana Water has water available from 2033 to 2133 to supply 7,580 AFY or 758,000 AF in total. The groundwater portion is 339,439 AF. The groundwater model indicates that 600,000 AF of groundwater can be withdrawn during that 100-year period but the water table would be lowered from 0-150 feet. What happens if recharge of all or a portion of the 339,439 AF occurs or does not occur? Will the Central Arizona Groundwater Replenishment District (CAGRD) replenish Marana Water's excess groundwater pumping (see below)? What happens if Arizona's Colorado River allocation is cut by 26%? These questions need to be factored into the analysis.


If you believe the DAWS approval, Marana Water can pump 7,580 AFY from now until 2133. That is equivalent to a population of 57,366 or 23,913 EDU. For sure, the groundwater modeling needs to be updated and redone as suggested above to verify these numbers.


D. Potable Water Master Plan-2010


Marana Water published a 2010 Potable Water Master Plan (Plan) [3] that projects water demands to 2015, 2020, 2030 and build-out. The Plan also developed the infrastructure requirements to service the projected demands including pipelines, pump stations, storage reservoirs and wells.


The Plan's fatal flaw is that it did not determine if water supplies were available to meet the projected demands. The Plan just assumed water was magically available.


For example, the Plan makes the following projected water demands:

  • 2020-10,302 AFY. This is 4.2 times the actual 2019 water demand (2,470 AFY) and 1.4 times the Estimated Demand (7,580 AFY) as utilized in the DAWS approval.

  • 2030-18,981 AFY. This is 2.5 times the Estimated Demand (7,580 AFY) utilized in the DAWS approval.

  • Build-Out-61,554 AFY. This is 8.1 times the DAWS Estimated Demand (7,580 AFY) for 2033 to 2133.


Therefore, the Plan demand projections are ludicrous and should not be relied upon for any water resource planning because it did not use realistic demand projections or synchronize with DAWS.


Marana Water indicates the Plan will might redone in FY21. The new Plan must be a 50-year plan and take a completely different approach and first determine the amount of water available via proper groundwater modeling as suggested above, then establish the realistic water demands and then develop related infrastructure needs.


E. Central Arizona Groundwater Replenishment District (CAGRD) Contract


Marana Water and CAGRD entered into a Member Service Area Agreement on 12/12/95.


Remember from Part III-Groundwater Management Act that CAGRD is a division of the Central Arizona Water Conservation District (CAWCD) and the Central Arizona Project (CAP) is the other division. CAGRD is the entity that has allowed groundwater withdrawals under the promise to recharge.


Marana Water was required to report a Minimum Quantity of Excess Groundwater for the period 1999 to 2014. Excess groundwater is that volume in excess of the amount of groundwater withdrawal established by the Assured Water Supply (AWS) for the system. Marana Water statisfied this requirement and CAGRD is now required to meet all Marana Water's groundwater recharge requirements. But can CAGRD meet this obligation?


The CAGRD Annual Report (2018) indicates that they are behind in satisfying recharge obligations in TAMA. Table 2.5 (below) shows that CAGRD was below required obligation in 2017 and 2018. How can they meet the obligation in the 100-year period 2033-2133?




Even CAGRD's Reserve Account for TAMA is only 31% of target. See Table 4 (below).



It is evident that CAGRD is unreliable and is promising to recharge groundwater with phantom water supplies.


In addition, if CAGRD water is utilize the cost is outrageous at $746/AF.


F. Groundwater Storage & Recover Facilities & AWBA


Marana Water has permits for the following Groundwater Storage Facilities:

  1. Marana Water Reclamation Facility (USF)-3,920 AFY-Effluent

  2. Cortaro Marana Irrigation District (GSF)-5,000 AFY-CAP

  3. BKW Farms (GSF)-14,351 AFY-CAP

  4. Lower Santa Cruz Replenishment Project (USF)-30,000 AFY-CAP

  5. Avra Valley Recharge Project (USF)-11,000 AFY-CAP

  6. Lower Santa Cruz River Managed (USF)

The Arizona Water Banking Authority (AWBA) has acquired LTSCs in TAMA to; (1) cover shortages on the Colorado River, (2) meet AMA goals, (3) tribal obligations and (4) interstate water banking. AWBA has acquired 820,161 LTSCs (AF) in TAMA as of 12/31/19. See Table 5 from AWBA Annual Report-2019 below. Of that amount, 706,577 AF is available for intrastate purposes. To put in perspective, if all of the intrastate water was available, it is only equal to about a little over two years of TAMA total water demand.



G. Long Term Storage Credits & Extinguishable Groundwater Rights


Marana secures LTSCs by storing non-groundwater sources (CAP Water and Effluent) in USFs or GSFs. Any stored water that is not used in the same year it was stored is eligible for LTSCs subject to a 5% cut-to-the-aquifer. For the 2017 DAWS application, Marana Water had 16,810 LTSCs. According to ADWR LTSCs Listing (4/30/20) [7]. Marana Water now has 14,434 LTSCs. This is equivalent to about 6 years of water demand at today's consumption rates.


According to the 2017 DAWS application, MW has 20,608 Extinguishable Groundwater Credits (EG Credits) that are un-pledged. These EG Credits were obtained via grandfathered groundwater rights either purchased or as part of a development agreement. They are primarily Type 1 rights. The EG Credits are one-time credits and can be used ton increase the Groundwater Allowance. The un-pledged EG Credits can also be sold or transferred.


H. Northwest Recharge, Recovery & Delivery System (NWRRDS)


NWRRDS is a project which tackles the sub-regional safe yield issue, i.e. groundwater pumping where recharge does not exist. Marana Water, Metro Water and Oro Valley Water have teamed up to transfer stored water at the Avra Valley Recharge Project and Lower Santa Cruz Recharge Project (both located near Marana Airport) to their respective service areas that are pumping groundwater without nearby recharge.


The project includes groundwater recovery wells, 7-mile transmission pipeline to a common reservoir and pump station site at Lambert/Twin Peaks. Here separate pumping facilities will deliver water to each agency. (See map below).




The water agencies will have the following project capacities:

  • Marana Water-2,400 AFY

  • Metro Water-4,000 AFY

  • Oro Valley-4,000 AFY

Metro Water owns, operates and manages the joint facilities. Total project cost is $36 million with Marana Water's cost share at $9.4 million.


I. PFAS/Dioxane Pollution & Treatment


The Airline/Lambert and Picture Rocks subsystems have been impacted by per- and polyfluoroalkyl substances (PFAs) and Dioxane pollution. These are chemicals used in the manufacture of commercial products. Marana Water's Unregulated Contaminants Web Page has more information on these compounds.


Two water treatment plants for each system have been designed utilizing ultraviolet advanced oxidation with granular activated carbon filtration. See process diagram below:




The total cost for these two water treatment facilities is $15 million and construction is expected to be completed in 2021. Marana Water is applying for low interest loans from the State Clean Water Revolving Fund.


3.0 Tucson Water


A. General Description

The Tucson Water Company was established in 1882 and was purchased by Tucson Water in 1900. Tucson Water has a potable water system and a reclaimed water system. Much of the data and exhibits for this section come from the Tucson Water Plan: 2000-2050 [4] and the most recent Tucson Water Plan Update-2012 [5].




The potable water system includes one large integrated system that serves 99% of Tucson Water customers including the Dove Mountain area. See map to the right. There are eight smaller, isolated potable water systems with independent wells and water distribution system infrastructure.






There are five well fields that service the potable water system. The Central, Avra Valley, Southside, and the Santa Cruz Well Fields pump native ground water and the CAVSRP Well Field pumps a blend of Colorado River Water and native groundwater. Therefore, Tucson Water is withdrawing water from both the Avra Valley and Upper Santa Cruz Sub-basins. See well field map to the left.

In 1979, Pima County [6] and Tucson Water entered into a Sewer Transfer Intergovernmental Agreement which provides that 90% of the regional wastewater collected and treated by Pima County is owned by Tucson Water. The remaining 10% remains with Pima County. The agreement also requires the first 28,200 acre-feet to be utilized in certain areas pursuant to the Southern Arizona Water Rights Settlement Act (SAWRSA).


Regional wastewater is treated at the Agua Nueva Water Reclamation Facility (WRF) (formerly Rogers WRF) and the the Tres Rios WRF (formerly Ina WRF). These facilities have treatment capacities of 32 million gallons per day (mgd) and 50 mgd, respectively.





In FY19, the Pima County WRFs reclaimed 57 million gallons per day (mgd) [63,848 AF] of regional wastewater. Of that amount, 40,856 AF was recharged and 16,145 was delivered to Tucson Water's reclaimed water system which includes 18 golf course, 65 schools and 50 parks [6].



The following basic statistics were provided by Tucson Water for 2019 [2]:


Potable Water System

  • Customers-233,809 [residential-218,556] [non-residential-15,253]

  • Customers (Marana)-5,311

  • Population Served-735,610

  • Wells-196 active

  • Water Stored-404,168 AF

  • Water Recharged-159,605 AF

  • Annual Production-100,614 acre-feet

  • Water Delivered-84,372 AF [residential-62,825 AF] [non-residential-21,547 AF]

  • Average Daily Demand (Delivered)-75.3 million gallons per day

  • Gallons Per Capita Per Day (Delivered)-102.4 Gallons Per Capita Per Day

  • Miles of Water Main-4,604 miles

  • Pump Stations-127 w/483 pumps

  • Storage Reservoirs-58 with total capacity of 315.6 million gallons

Recycled Water System

  • Recycled Water Delivered-11,366 AF

  • Recycled Water Customers-1,041

  • Pump Stations-11 w/41 pumps

  • Storage Reservoirs-6 with total storage of 15.9 million gallons


B. Groundwater Allowance



Tucson Water's beginning Groundwater Allowance balance in 2019 was 1,278,814.45 AF and 0.0 AF of groundwater was withdrawn leaving 1,278,814.45 AF in the Groundwater Allowance Account. See CAGRD-2019 Annual Report above. This is equivalent to about 12.7 years of water demand at today's consumption rate.


C. Designated Assured Water Supply (DAWS)


Tucson Water most recent DAWS (2024) was approved by ADWR on 10/16/14.




Tucson Water's 2024 Estimated Demand is 155,346 AFY. The figure to the right shows the Components.










Tucson Water's Assured Water Supply is 182,852 AFY. The figure to the left shows the Components.








The Groundwater Component is typically calculated using the following formula:

Groundwater Component = Groundwater Allowance + Incidental Recharge + CAGRD Contract Excess Groundwater + Remediation Water

For Tucson Water's 2014 DAWS application this was calculated as:


Groundwater Component=12,537.6 + 6,213.82 + 12,500 + 509.74=31,761.16 AFY


The Tucson Water DAWS approval then states that 31,761.16 AFY is physically and legally available and it comes directly from the calculation! There is no reference to a hydrology report and it is not clear if groundwater modeling was utilized.


The Designation is the official approval from ADWR that Tucson Water has water available from 2033 to 2133 to supply 182,852.14 AFY or 18,285,214 AF in total.


D. 50-Year Water Plan


Tucson Water developed a 50-Year Water Plan for the period 2000-2050. The Water Plan was updated in 2008 and 2012 and is currently going through another update.




The 2012 Update shows projected demands for a range of gallons per capita per day (GPCD) use. See chart to the left. For example, using 145 GPCD (high-range) results in a projected demand of 180,000 AFY in 2050. This is based on a population of 1,090,000 in 2050.









The 2012 Update also projects reclaimed water demand at 15,000 AFY in 2030. See chart to the right.







Figure 6.1 (below) shows that Tucson Water's Colorado River water supply is sufficient to meet demand at the 145 GPCD average usage until about 2030 when the total demand is 140,000 AFY. Beyond that, new additional renewable supplies will be needed along with depleting any water from storage.



E. Central Arizona Groundwater Replenishment District (CAGRD) Contract


Tucson Water and the Central Arizona Groundwater Replenishment District (CAGRD) entered into a Member Service Area Agreement on 12/19/96. This Agreement provides that Tucson Water make CAP water and storage facilities available to CAGRD when excess groundwater withdrawals exceed 12,500 AFY.


F. Tucson Water Groundwater Storage & Recovery


Tucson Water has permits for the following Groundwater Storage Facilities:

  1. Sweetwater Recharge Facilities (USF)-13,000 AFY-Effluent

  2. Central Avra Valley Storage and Recovery Project (CAVSRP)(USF)-100,000 AFY-CAP

  3. South Avra Valley Storage and Recovery Project (SAVSARP) (USF)-60,000 AFY-CAP

  4. Pima Mine Road Recharge Project (USF)-30,000 AFY-CAP

G. Long Term Storage Credits & Extinguishable Groundwater Rights


Tucson Water secures LTSCs by storing non-groundwater sources (CAP Water and Effluent) in USFs or GSFs. Any stored water that is not used in the same year it was stored is eligible for LTSCs subject to a 5% cut-to-the-aquifer. For the 2014 DAWS application, Tucson Water had 206,898 LTSCs. According to ADWR LTSCs Listing (4/30/20 [7]. Tucson Water now has 404,168 LTSCs. This is equivalent to 4 years of water demand at today's consumption rates.


H. Regional Recharge, Recovery & Delivery Projects -None


I. Groundwater Pollution & Treatment


A large plume near the Tucson Airport is contaminated with trichloroethene (TCE) and 1,4-Dioxane. The Tucson Airport Remediation Project (TARP) is a USEPA Superfund Project that includes remediation of 6.5 million gallons per day of contaminated groundwater utilizing Advanced Oxidation Process (AOP) treatment. All Tucson Water production wells in the area have been turned off or converted to irrigation wells.


Conclusions


Town of Marana-Joint Service Areas

  • Potable water service in Marana is provided by Marana Water (8,150 customers) and Tucson Water (233,809 customers with 5,311 customers in Marana).

  • Tucson Water owns the rights to 90% of Pima County regional wastewater and has an extensive reclaimed (non-potable) water system (1,041 customers) that services golf courses in the Dove Mountain area of Marana.

  • Marana Water and Tucson Water have an Intergovernmental Agreement (IGA) that defines the areas that Tucson Water could serve within Marana town boundaries.

  • Tucson Water operates under the Tucson Water Service Area Policy that limits potable water service outside its designated service areas.

  • Tucson Water cannot provide potable water service to the Tortolita Preserve and surrounding Arizona State Lands.

  • Marana Water apparently does not intend to provide water service to the Tortolita Preserve and surrounding State Lands (white areas) based on the above map colorings.

  • Marana Water and Tucson Water each should prepare an Annual Report providing basic water utility statistics, status of water demand versus supply, major accomplishments for the year and upcoming projects and activities. It is unbelievable that such a public document does not currently exist. Pima County Wastewater Reclamation's By The Numbers Report is a good example of such an Annual Report.

  • Marana Water and Tucson Water need to provide basic water utility information, documents and agreements as presented here on their respective websites. This will avoid the need for Public Record Requests.


Marana Water

  • Marana Water has a Groundwater Allowance of 3,136.48 AF which is only equivalent to 1.3 years of current groundwater production. Once depleted, excess groundwater withdrawals must come from recharged renewable sources (CAP or Effluent).

  • Marana Water has a Designated Assured Water Supply (DAWS) of 7,580 AFY for the period from 2016 to 2033 and the 100-year period to 2133. This is equivalent to a population of 57,366 or 23,913 Equivalent Dwelling Units (EDU) but is based on sketchy hydrology/groundwater modeling analysis.

  • Marana Water DAWS is based on a convoluted groundwater modeling approach which determines how much groundwater can be pumped to a maximum drawdown of 1,000 below ground surface rather than demonstrating how much groundwater can be pumped over a 100-year period and maintain safe yield and reduce/eliminate accumulated overdraft.

  • Marana Water has an agreement with the Central Arizona Groundwater Replenishment District (CAGRD) to replenish all of its excess groundwater withdrawals but CAGRD is behind in meeting its obligations.

  • Marana Water's 2010 Potable Water Master Plan is flawed as it projects water demands based on phantom water supplies. Marana Water needs to prepare a 50-Year Water Management Plan that first establishes the amount of groundwater water available based on comprehensive groundwater modeling and then establishes the realistic water demands. The Plan should be based on a 75% reliability of Colorado River water.

  • Two of the seven separate and isolated water systems are polluted with PFAs and Dioxane and require treatment costing $15 million.

  • Marana Water is working with Metro-Water and Oro Valley Water on the Northwest Recharge, Recovery & Delivery System (NWRRDS) which will reduce groundwater withdrawals in areas with no recharge---a primary TAMA goal.


Tucson Water

  • Tucson Water has a Groundwater Allowance of 1,278,814.45 AF which is equivalent to 12.7 years of current groundwater production. Once depleted, excess groundwater withdrawal must come from recharged renewable sources (CAP or Effluent).

  • Tucson Water has an agreement with CAGRD which provides that Tucson Water make CAP water and storage facilities available to CAGRD when excess groundwater withdrawals exceed 12,500 AFY.

  • Tucson Water has a Designated Assured Water Supply (DAWS) of 182,852 AFY for the period from 2014-2024 and the 100-year period to 2124. It is not clear if this was based on a hydrology/groundwater model study but this study should be undertaken as recommended above for Marana Water.

  • Tucson Water's 50-Year Water Plan-2012 Update indicates that additional reliable water supplies will be needed after 2040 (assuming 145 gpcd demand). This Plan should be updated as recommended for Marana Water.

  • Groundwater near the Tucson Airport is contaminated with PCE and Dioxane and is a USEPA Superfund Site. The Tucson Airport Remediation Project (TARP) treats 6.5 million gallons per day of contaminated groundwater utilizing Advanced Oxidation Process (AOP) treatment.


Tuscon Active Management Area (TAMA)

  • CAGRD did not meet its recharge obligations in TAMA in 2018, 2019 and only has 31% in groundwater reserves.

  • AWBA has 706,577 AF of intrastate Long Term Storage Credits in TAMA which is only equivalent to about 2 years of TAMA total water demand.



Marana Water and Tucson Water have sufficient renewable non-groundwater supplies to meet projected potable water demand in the short-term (less than 10 years). However, comprehensive hydrology/groundwater modeling is required to demonstrate how much groundwater can be pumped over the long-term (50-years) and maintain safe yield and reduce/eliminate accumulated overdraft. This 50-Year Water Management Plan analysis must be based on realistic and reliable replenishment of non-groundwater sources, e.g. 75% reliability of Colorado River Water no more promises to serve now and maybe recharge later.




Know Your H2O Conclusions Are Next





Notes:



[1] Marana Water-2019 Annual Withdrawal & Use Report


[2] Tucson Water-2019 Annual Withdrawal & Use Report


[3] Marana Water-2010 Potable Water Master Plan


[4] Tucson Water-50 Year Water Plan


[5] Tucson Water-50 Year Water Plan-2012 Update


[6] Pima County Wastewater Reclamation-By The Numbers-2018/19


[7] ADWR Recharge Credits & Accounting Website




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