Ariz. Admin. Code § 18-11-606

Current through Register Vol. 30, No. 25, June 21, 2024

Section R18-11-606 - TMDL Priority Criteria for 303(d) Listed Surface Waters or Segments

A. In addition to the factors specified in A.R.S. § 49-233(C), the Department shall consider the following when prioritizing an impaired water for development of TMDLs:

1. A change in a water quality standard;

2. The date the surface water or segment was added to the 303(d) List;

3. The presence in a surface water or segment of species listed as threatened or endangered under section 4 of the Endangered Species Act;

4. The complexity of the TMDL;

5. State, federal, and tribal policies and priorities; and

6. The efficiencies of coordinating TMDL development with the Department's surface water monitoring program, the watershed monitoring rotation, or with remedial programs.

B. The Department shall prioritize an impaired surface water or segment for TMDL development based on the factors specified in A.R.S. § 49-233(C) and subsection (A) as follows:

1. Consider an impaired surface water or segment a high priority if:

a. The listed pollutant poses a substantial threat to the health and safety of humans, aquatic life, or wildlife based on:

i. The number and type of designated uses impaired;

ii. The type and extent of risk from the impairment to human health, aquatic life, or wildlife;

iii. The pollutant causing the impairment, or

iv. The severity, magnitude, and duration the surface water quality standard was exceeded;

b. A new or modified individual NPDES or AZPDES permit is sought for a new or modified discharge to the impaired water;

c. The listed surface water or segment is listed as a unique water in A.A.C. R18-11-112 or is part of an area classified as a "wilderness area," "wild and scenic river," or other federal or state special protection of the water resource;

d. The listed surface water or segment contains a species listed as threatened or endangered under the federal Endangered Species Act and the presence of the pollutant in the surface water or segment is likely to jeopardize the listed species;

e. A delay in conducting the TMDL could jeopardize the Department's ability to gather sufficient credible data necessary to develop the TMDL;

f. There is significant public interest and support for the development of a TMDL;

g. The surface water or segment has important recreational and economic significance to the public; or

h. The pollutant is listed for eight years or more.

2. Consider an impaired surface water or segment a medium priority if:

a. The surface water or segment fails to meet more than one designated use;

b. The pollutant exceeds more than one surface water quality standard;

c. A surface water quality standard exceedance is correlated to seasonal conditions caused by natural events, such as storms, weather patterns, or lake turnover;

d. It will take more than two years for proposed actions in the watershed to result in the surface water attaining applicable water quality standards;

e. The type of pollutant and other factors relating to the surface water or segment make the TMDL complex; or

f. The administrative needs of the Department, including TMDL schedule commitments with EPA, permitting requirements, or basin priorities that require completion of the TMDL.

3. Consider an impaired surface water or segment a low priority if:

a. The Department has formally submitted a proposal to delist the surface water, segment, or pollutant to EPA based on R18-11-605 (E)(2). If the Department makes the submission outside the listing process cycle, the change in priority ranking will not be effective until EPA approves the submittal;

b. The Department has modified, or formally proposed for modification, the designated use or applicable surface water quality standard, resulting in an impaired water no longer being impaired, but the modification has not been approved by EPA;

c. The surface water or segment is expected to attain surface water quality standards due to any of the following:

i. Recently instituted treatment levels or best management practices in the drainage area,

ii. Discharges or activities related to the impairment have ceased, or

iii. Actions have been taken and controls are in place or scheduled for implementation that will likely to bring the surface water back into compliance;

d. The surface water or segment is ephemeral or intermittent. The Department shall re-prioritize the surface water or segment if the presence of the pollutant in the listed water poses a threat to the health and safety of humans, aquatic life, or wildlife using the water, or the pollutant is contributing to the impairment of a downstream perennial surface water or segment;

e. The pollutant poses a low ecological and human health risk;

f. Insufficient data exist to determine the source of the pollutant load;

g. The uncertainty of timely coordination with national and international entities concerning international waters;

h. Naturally occurring conditions are a major contributor to the impairment; and

i. No documentation or effective analytical tools exist to develop a TMDL for the surface water or segment with reasonable accuracy.

C. The Department will target surface waters with high priority factors in subsections (B)(1)(a) through (B)(1)(d) for initiation of TMDLs within two years following EPA approval of the 303(d) List.

D. The Department may shift priority ranking of a surface water or segment for any of the following reasons:

1. A change in federal, state, or tribal policies or priorities that affect resources to complete a TMDL;

2. Resource efficiencies for coordinating TMDL development with other monitoring activities, including the Department's ambient monitoring program that monitors watersheds on a five-year rotational basis;

3. Resource efficiencies for coordinating TMDL development with Department remedial or compliance programs;

4. New information is obtained that will revise whether the surface water or segment is a high priority based on factors in subsection (B); and

5. Reduction or increase in staff or budget involved in the TMDL development.

E. The Department may complete a TMDL initiated before July 12, 2002 for a surface water or segment that was listed as impaired on the 1998 303(d) List but does not qualify for listing under the criteria in R18-11-605, if:

1. The TMDL investigation establishes that the water quality standard is not being met and the allocation of loads is expected to bring the surface water into compliance with standards,

2. The Department estimates that more than 50 percent of the cost of completing the TMDL has been spent,

3. There is community involvement and interest in completing the TMDL, or

4. The TMDL is included within an EPA-approved state workplan initiated before July 12, 2002.

Ariz. Admin. Code § R18-11-606

New Section made by final rulemaking at 8 A.A.R. 3380, effective July 12, 2002 (Supp. 02-3).