Assigned to NR AS VETOED
ARIZONA STATE SENATE
Fifty-Seventh Legislature, First Regular Session
VETOED
FACT SHEET FOR H.B. 2270
groundwater model; stormwater recharge; AMAs
Purpose
Requires the Director of the Arizona Department of Water Resources (ADWR) to adopt
rules and annually update the groundwater model for active management areas (AMA) to account
for new natural, incidental or artificial stormwater recharge.
Background
The 1980 Groundwater Management Act established AMAs as part of a comprehensive
management framework to address groundwater rights and groundwater overdraft. Currently, there
are seven AMAs which include Phoenix, Tucson, Pinal, Prescott, Santa Cruz, Douglas and
Willcox. An AMA is a geographical area that has been designated as requiring active management
of groundwater or, in the case of the Santa Cruz AMA, active management of any water, other
than stored water, withdrawn from a well (A.R.S. Title 45, Chapter 2, Article 2).
ADWR uses groundwater flow modeling to simulate past, present and future impacts of
water use on aquifers. Groundwater conditions in Arizona are typically evaluated by analytical
models, which present a simplistic evaluation of an aquifer and numeric models, which capture an
aquifer's complexity. ADWR has developed regional, numeric groundwater models to simulate
Arizona's water supply and future demands. Components of the modeled area including pumpage,
recharge, evapotranspiration, streamflow and flow. Across model boundaries are simulated within
each regional model developed by ADWR (ADWR: Groundwater Modeling Section and ADWR:
Modeling Basics).
There is no anticipated fiscal impact to the state General Fund associated with this
legislation.
Provisions
1. Requires the Director of ADWR to adopt rules to update ADWR's groundwater modeling for
AMAs.
2. Requires the updated adopted rules to account for any natural, incidental or artificial
stormwater recharge to the groundwater basin created through the development of new or
existing infrastructure.
3. Requires the Director of ADWR to assume that the stormwater recharge generated by the
development of new or existing infrastructure will offset a portion of future groundwater use. FACT SHEET – Vetoed
H.B. 2270
Page 2
4. Requires the Director of ADWR to annually update the groundwater model for AMAs to
reflect new natural, incidental or artificial stormwater recharge.
5. Becomes effective on the general effective date.
Governor's Veto Message
The Governor indicates in her veto message that H.B. 2270 weakens rural groundwater
protections when rural Arizonans have been asking the Legislature for years to institute meaningful
rural groundwater management measures, and that she will not consider rural groundwater
legislation outside of the context of ongoing negotiations for an alternative framework for rural
groundwater management.
House Action Senate Action
NREW 2/11/25 DP 6-4-0-0 NR 3/11/25 DP 5-3-0
3
rd
Read 2/20/25 32-26-2 3
rd
Read 4/9/25 17-13-0
Vetoed by the Governor 4/15/25
Prepared by Senate Research
April 16, 2025
SB/SN/slp