Arizona Administrative Code › Title 18 - ENVIRONMENTAL QUALITY › Chapter 11 - DEPARTMENT OF ENVIRONMENTAL QUALITY - WATER QUALITY STANDARDS › Article 1 - WATER QUALITY STANDARDS FOR SURFACE WATERS › Section R18-11-104 - Designated Uses

Current through Register Vol. 30, No. 28, July 12, 2024
A. The Director
				shall adopt or remove a designated use or subcategory of a designated use by
				rule.
B. Designated uses of a
				surface water may include full-body contact, partial-body contact, domestic
				water source, fish consumption, aquatic and wildlife (cold water), aquatic and
				wildlife (warm water), aquatic and wildlife (ephemeral), aquatic and wildlife
				(effluent-dependent water), agricultural irrigation, and agricultural livestock
				watering. The designated uses for specific surface waters are listed in
				Appendix B of this Article.
C.
				Numeric water quality criteria to maintain and protect water quality for the
				designated uses are prescribed in Appendix A,
				R18-11-109,
				R18-11-110,
				and R18-11-112. Narrative water quality standards to protect all surface waters
				are prescribed in
				R18-11-108.
D. If a surface water has more than one
				designated use listed in Appendix B, the most stringent water quality criterion
				applies.
E. The Director shall
				revise the designated uses of a surface water if water quality improvements
				result in a level of water quality that permits a use that is not currently
				listed as a designated use in Appendix B.
F. In designating uses of a surface water and
				in establishing water quality criteria to protect the designated uses, the
				Director shall take into consideration the applicable water quality standards
				for downstream surface waters and shall ensure that the water quality standards
				that are established for an upstream surface water also provide for the
				attainment and maintenance of the water quality standards of downstream surface
				waters.
G. A use attainability
				analysis shall be conducted prior to removal of a designated use or adoption of
				a subcategory of a designated use that requires less stringent water quality
				criteria.
H. The Director may
				remove a designated use or adopt a subcategory of a designated use that
				requires less stringent water quality criteria, provided the designated use is
				not an existing use and it is demonstrated through a use attainability analysis
				that attaining the designated use is not feasible for any of the following
				reasons:
1. A naturally-occurring pollutant
				concentration prevents the attainment of the use;
2. A natural, ephemeral, intermittent, or
				low-flow condition or water level prevents the attainment of the use;
3. A human-caused condition or source of
				pollution prevents the attainment of the use and cannot be remedied or would
				cause more environmental damage to correct than to leave in place;
4. A dam, diversion, or other type of
				hydrologic modification precludes the attainment of the use, and it is not
				feasible to restore the surface water to its original condition or to operate
				the modification in a way that would result in attainment of the use;
5. A physical condition related to the
				natural features of the surface water, such as the lack of a proper substrate,
				cover, flow, depth, pools, riffles, and the like, unrelated to water quality,
				precludes attainment of an aquatic life designated use; or
6. Controls more stringent than those
				required by § 301 (b) and § 306 of the Clean Water Act [33 U.S.C.
				§ 1311 and § 1316] are necessary to attain the use and implementation
				of the controls would result in substantial and widespread economic and social
				impact.