49-232

49-232. Lists of impaired waters; data
requirements; rules

A. At least once every five years, the department shall prepare a list of impaired
waters for the purpose of complying with section 303(d) of the clean water act (33 United
States Code section 1313(d)). The department shall provide public notice and allow for
comment on a draft list of impaired waters prior to its submission to the United States
environmental protection agency. The department shall prepare written responses to
comments received on the draft list. The department shall publish the list of impaired
waters that it plans to submit initially to the regional administrator and a summary of
the responses to comments on the draft list in the Arizona administrative register at
least forty-five days before submission of the list to the regional administrator.
Publication of the list in the Arizona administrative register is an appealable agency
action pursuant to title 41, chapter 6, article 10 that may be appealed by any party that
submitted written comments on the draft list. If the department receives a notice of
appeal of a listing pursuant to section 41-1092, subsection B within forty-five days of
the publication of the list in the Arizona administrative register, the department shall
not include the challenged listing in its initial submission to the regional
administrator. The department may subsequently submit the challenged listing to the
regional administrator if the listing is upheld in the director's final administrative
decision pursuant to section 41-1092.08, or if the challenge to the listing is withdrawn
prior to a final administrative decision.

B. In determining whether a water is impaired, the department shall consider only
reasonably current credible and scientifically defensible data that the department has
collected or has received from another source. Results of water sampling or other
assessments of water quality, including physical or biological health, shall be
considered credible and scientifically defensible data only if the department has
determined all of the following:

1. Appropriate quality assurance and quality control procedures were followed and
documented in collecting and analyzing the data.

2. The samples or analyses are representative of water quality conditions at the
time the data was collected.

3. The data consists of an adequate number of samples based on the nature of the
water in question and the parameters being analyzed.

4. The method of sampling and analysis, including analytical, statistical and
modeling methods, is generally accepted and validated in the scientific community as
appropriate for use in assessing the condition of the water.

C. The department shall adopt by rule the methodology to be used in identifying
waters as impaired. The rules shall specify all of the following:

1. Minimum data requirements and quality assurance and quality control requirements
that are consistent with subsection B of this section and that must be satisfied in order
for the data to serve as the basis for listing and delisting decisions.

2. Appropriate sampling, analytical and scientific techniques that may be used in
assessing whether a water is impaired.

3. Any statistical or modeling techniques that the department uses to assess or
interpret data.

4. Criteria for including and removing waters from the list of impaired waters,
including any implementation procedures developed pursuant to subsection F of this
section. The criteria for removing a water from the list of impaired waters shall not be
any more stringent than the criteria for adding a water to that list.

D. In assessing whether a water is impaired, the department shall consider the data
available in light of the nature of the water in question, including whether the water is
an ephemeral water. A water in which pollutant loadings from naturally occurring
conditions alone are sufficient to cause a violation of applicable surface water quality
standards shall not be listed as impaired.

E. If the department has adopted a numeric surface water quality standard for a
pollutant and that standard is not being exceeded in a water, the department shall not
list the water as impaired based on a conclusion that the pollutant causes a violation of
a narrative or biological standard unless:

1. The department has determined that the numeric standard is insufficient to
protect water quality.

2. The department has identified specific reasons that are appropriate for the
water in question, that are based on generally accepted scientific principles and that
support the department's determination.

F. Before listing a navigable water as impaired based on a violation of a narrative
or biological surface water quality standard and after providing an opportunity for
public notice and comment, the department shall adopt implementation procedures that
specifically identify the objective basis for determining that a violation of the
narrative or biological criterion exists. A total maximum daily load designed to achieve
compliance with a narrative or biological surface water quality standard shall not be
adopted until the implementation procedure for the narrative or biological surface water
quality standard has been adopted.

G. On request, the department shall make available to the public data used to
support the listing of a water as impaired and may charge a reasonable fee to persons
requesting the data.

H. By January 1, 2002, the department shall review the list of waters identified as
impaired as of January 1, 2000 to determine whether the data that supports the listing of
those waters complies with this section. If the data that supports a listing does not
comply with this section, the listed water shall not be included on future lists
submitted to the United States environmental protection agency pursuant to 33 United
States Code section 1313(d) unless in the interim data that satisfies the requirements of
this section has been collected or received by the department.

I. The department shall add a water to or remove a water from the list using the
process described in section 49-232, subsection A outside of the normal listing cycle if
it collects or receives credible and scientifically defensible data that satisfies the
requirements of this section and that demonstrates that the current quality of the water
is such that it should be removed from or added to the list. A listed water may no longer
warrant classification as impaired or an unlisted water may be identified as impaired if
the applicable surface water quality standards, implementation procedures or designated
uses have changed or if there is a change in water quality.