Water

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Pinal AMA

• Water
• Management Goal
• Dennis Kimberlin
• Area Director

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Interpreting the Pinal AMA Goal

• Often referred to as Planned Depletion
• In 1979, the Arizona Groundwater Study Commission
  introduced the concept of Planned Depletion and
  defined it as

a management goal under which an overdraft of
groundwater would be permitted to occur under
controlled conditions to result in a
predetermined depth to groundwater at the end of
a given period of time
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Groundwater Code Language (A.R.S. 45-562)

• The management goal of the Pinal AMA is to allow
  development of non-irrigation uses and to
  preserve existing agricultural economies in the
  active management area for as long as feasible,
  consistent with the necessity to preserve future
  water supplies for non-irrigation uses.

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Multi-Faceted Management Goal

• Allow Development of Non-Irrigation Uses
• Preserve Existing Agricultural Economies
• Preserve Future Water Supplies for
  Non-Irrigation Uses

Websters Dictionary Keep up, carry
on, or maintain Rogets Thesaurus
Sustain, prolong, continue, uphold, or protract
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The Multi-Faceted Goal

• Allows for groundwater mining in order to help
  preserve agricultural economies
• Implies that water supplies for municipal and
  industrial uses be sustainable

Therefore Goal attainment involves balancing the
preservation of agriculture with the need to
sustain water supplies for current and future
non-irrigation uses
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Preserve Existing Agricultural Economies

• Allow a managed overdraft of groundwater to occur
  to a prescribed depth over a given period of time
• This Managed Groundwater Use (MGU) concept
  would be coupled with existing or new
  conservation programs to help preserve
  agricultural economies

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MGU Concept

• Manages available groundwater in storage to a
  depth of 1,000 feet over the next 100 years
• Establishes a planned depletion allowance (PDA)
  within the AMAs two principal sub-basins
• PDA the amount of mined groundwater that could
  be pumped each year by the agricultural sector

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Elements of the MGU Concept

• Allowable Groundwater Use (AGU)
  PDA Incidental recharge by agriculture
• 300,000 AF 185,000 AF 485,000 AF
• Groundwater Savings Account (GSA)
• An AMA long-term bank account to help manage
  groundwater withdrawals
• Considers the cyclical nature of agricultural
  water use
• Places limitations on groundwater withdrawals by
  agriculture, thereby helping to protect supplies
  for municipal and industrial uses

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Preserve Future Water Supplies for Non-Irrigation
Uses (SMP and TMP)

• Groundwater reserved between 1,000 and 1,200 feet
  for MI uses (4.2 MAF)
• Adequate for 200,000 people for 200 years
• However, because these reserved groundwater
  supplies are finite...

It may be inappropriate and inconsistent with
good water management to allow future development
to occur on non-renewable water supplies
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Preserve Future Water Suppliesfor Non-Irrigation
Uses

• The Department now interprets the aboveas
  calling for a reliable and sustainable supply of
  water for MI uses

This interpretation requires the use of renewable
supplies but would allow for the mining of
groundwater by municipal providers during
appropriate times such as drought periods and
other supply interruptions
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Renewable Water Suppliesfor Non-Irrigation Uses
207,000 AF of Renewable Supplies
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Future Sustainable Populationson Renewable Water
Supplies
Assuming a future GPCD rate of 125
1.4 Million People on Renewable Supplies
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Future Sustainable Populationson Renewable Water
Supplies
Assuming a future GPCD rate of 250
749,000 People on Renewable Supplies
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Demographics
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Demographics
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Additional Renewable Water Supplies
Assuming No Overdraft
297,000 AF of Renewable Supplies
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Additional Suppliesto Sustain Future Populations
No Overdraft
Assumes Overdraft
1,071,000
749,000
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Allow Developmentof Non-Irrigation Uses

• The Department supports the development of
  municipal and industrial uses as long as such
  uses are

• Met with 100 renewable supplies
• or
• Fully replenished if met with mined
  groundwater

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Transitioning to Predominately Non-Irrigation
Demands

• Agriculture will most likely remain economically
  viable well into this century
• After CAP is no longer available, agriculture is
  expected to hasten conversion of land to
  non-irrigation uses
• When groundwater is no longer economical to pump,
  farms will cease production
• Current projections suggest around 2090

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Relic Groundwater Suppliesfor Municipal Uses

• Estimates show about 14 to 15 MAF may remain to a
  depth of 1,200 feet
• These relic supplies may be used during drought
  periods for firming renewable supplies
• Relic supplies could provide a short-term backup
  for temporary water supply interruptions
• Also available for use... if future generations
  so choose

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Potential Impacts of Mining Relic Groundwater
Supplies

• Assuming 15 MAF of relic groundwater supplies
  remain in storage to 1,200 feet

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Groundwater AllowancesUnder Existing AWS Rules

• Pinal AMA allocation is inconsistent with
  long-term sustainability

• The Rules also allow in the Pinal AMA a permanent
  extinguishment credit of 1.5 AF per acre for
  irrigated lands

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Potential Impactsof the Management Goal

• Major Benefits

• Major Costs

• Preservation
• Certainty
• Sustainability
• Resource-based

• Declining aquifers
• Land subsidence
• Water quality
• Population limits

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Water Management Program Elements

• Assured Water Supply Rules
• Drought Protection
• Sub-Area/Critical Area Management
• Augmentation and Recharge Program
• Conservation Programs
• Long-Range Planning
• Water Management Assistance

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Questions Discussion