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 R18-11-101 - Definitions

Current through Register Vol. 30, No. 28, July 12, 2024
The following terms apply to this Article:
1. "Acute toxicity" means toxicity involving
				a stimulus severe enough to induce a rapid response. In aquatic toxicity tests,
				an effect observed in 96 hours or less is considered acute.
2. "Agricultural irrigation (AgI)" means the
				use of a surface water for crop irrigation.
3. "Agricultural livestock watering (AgL)"
				means the use of a surface water as a water supply for consumption by
				livestock.
4. "Annual mean" is the
				arithmetic mean of monthly values determined over a consecutive 12-month
				period, provided that monthly values are determined for at least three months.
				A monthly value is the arithmetic mean of all values determined in a calendar
				month.
5. "Aquatic and wildlife
				(cold water) (A&Wc)" means the use of a surface water by animals, plants,
				or other cold-water organisms, generally occurring at an elevation greater than
				5000 feet, for habitation, growth, or propagation.
6. "Aquatic and wildlife (effluent-dependent
				water) (A&Wedw)" means the use of an effluent-dependent water by animals,
				plants, or other organisms for habitation, growth, or propagation.
7. "Aquatic and wildlife (ephemeral)
				(A&We)" means the use of an ephemeral water by animals, plants, or other
				organisms, excluding fish, for habitation, growth, or propagation.
8. "Aquatic and wildlife (warm water)
				(A&Ww)" means the use of a surface water by animals, plants, or other
				warm-water organisms, generally occurring at an elevation less than 5000 feet,
				for habitation, growth, or propagation.
9. "Arizona Pollutant Discharge Elimination
				System (AZPDES)" means the point source discharge permitting program
				established under 18 A.A.C. 9, Article 9.
10. "Assimilative capacity" means the
				difference between the baseline water quality concentration for a pollutant and
				the most stringent applicable water quality criterion for that
				pollutant.
11. "Clean Water Act"
				means the Federal Water Pollution Control Act [33 U.S.C. 1251 to
				1387] .
12. "Complete Mixing" means the location at
				which concentration of a pollutant across a transect of a surface water differs
				by less than five percent.
13.
				"Criteria" means elements of water quality standards that are expressed as
				pollutant concentrations, levels, or narrative statements representing a water
				quality that supports a designated use.
14. "Critical flow conditions of the
				discharge" means the hydrologically based discharge flow averages that the
				director uses to calculate and implement applicable water quality criteria to a
				mixing zone's receiving water as follows:
a.
				For acute aquatic water quality standard criteria, the discharge flow critical
				condition is represented by the maximum one-day average flow analyzed over a
				reasonably representative timeframe.
b. For chronic aquatic water quality standard
				criteria, the discharge flow critical flow condition is represented by the
				maximum monthly average flow analyzed over a reasonably representative
				timeframe.
c. For human health
				based water quality standard criteria, the discharge flow critical condition is
				the long-term arithmetic mean flow, averaged over several years so as to
				simulate long-term exposure.