(a)General requirements for antidegradation analyses.The department's antidegradation policy under 18 AAC 70.015 applies to all waters of this state. The provisions of 18 AAC 70.015(a)(1) - (3) identify three tiers of water quality and water quality protection, Tiers 1, 2, and 3 respectively. In implementing the antidegradation policy for a water of the United States within this state, the following provisions apply:
(1) the department will make an antidegradation analysis and findings for discharges subject to authorization by the department under(A) 18 AAC 83 (Alaska Pollutant Discharge Elimination System (APDES) Program); and(B)33 U.S.C. 1341 (Clean Water Act, sec. 401) water quality certifications; for 33 U.S.C. 1341 (Clean Water Act, sec. 401) water quality certifications of 33 U.S.C. 1344 (Clean Water Act, sec. 404) permits, the department may determine upon review whether an evaluation and findings of no significant degradation under 33 U.S.C. 1344 and under 40 C.F.R. Part 230, revised as of July 1, 2017 and adopted by reference, are sufficient to comply with state antidegradation requirements for Tiers 1 and 2 under this section with regard to water quality impacts to receiving water immediately surrounding the dredge or fill material; in the antidegradation findings the department will consider where the fill would be placed and impacts to the receiving water from the fill activity; only temporary and limited degradation may be authorized in Tier 3 water, in accordance with (d)(4)(A) of this section; (2) the department will not make an antidegradation analysis and findings for (A) activities proposed for the express purpose of watershed protection or restoration if the applicant supplies information and the department finds that the antidegradation analysis is not required because the lowering of water quality would be temporary and limited and is necessary to secure long-term water quality improvement, including projects for the protection or attainment of existing and designated uses in water where the department determines that those uses have been impaired or threatened due to the loss or diminishment of the water's natural characteristics; projects under this subparagraph shall implement all department-required practicable best management practices;(B) emergency response actions under the direction of a federal or state on-scene coordinator, designated under 33 U.S.C. 1321, AS 46.04.020, or AS 46.09.020, if any lowering of water quality is temporary and limited and existing uses are maintained and protected; the responsible party whose actions or lack of action necessitated an emergency response action shall address any lowering of water quality that is not temporary and limited; existing law may be used to address restoration, rehabilitation, replacement, or acquisition of the equivalent for the affected natural resources, including long-term water quality impacts;(C)33 U.S.C. 1341 (Clean Water Act, sec. 401) certifications where the department has waived certification under 33 U.S.C. 1341(a); this subparagraph does not alter federal agencies' existing obligations under 40 C.F.R. 230.10(b)(1) to issue permits in compliance with state water quality standards, including antidegradation provisions; or(D) amendments to this chapter, including amendments to the water use classes and subclasses, amendments to water quality criteria, adoption of site-specific criteria, and the reclassification of waters;(3) an antidegradation analysis is tier-specific as described under (b), (c), and (d) of this section; antidegradation analyses and department findings for Tier 1 and Tier 2 protection levels are on a parameter-by-parameter basis; analysis and department findings for Tier 3 water are on a basis of a designated water;(4) an antidegradation analysis for a discharge under 18 AAC 83 (Alaska Pollutant Discharge Elimination System (APDES) Program) specified in (1)(A) of this subsection is subject to the public participation and intergovernmental review procedures under 18 AAC 83.120; an antidegradation analysis for a 33 U.S.C. 1341 (Clean Water Act, sec. 401) certification of a discharge under (1)(B) of this subsection is subject to the public participation and intergovernmental review procedures under 18 AAC 70.015(c);(5) the applicant shall submit sufficient information to complete an antidegradation analysis under (b), (c), and (d) of this section on department-approved forms; the department will review and determine whether the information is sufficient; information required for department review must include(A) identification of the receiving water, including the geographic extent potentially affected by the proposed discharge;(B) a description of the project purpose;(C) the type of facility, activity, and discharge;(E) parameters of concern in the discharge and the respective concentrations, persistence, and potential impacts to the receiving water;(F) data on parameters that may alter the effects of the discharge to the receiving water;(G) which tier should apply for each parameter of concern, if applicable; and(H) any additional information as requested by the department;(6) if determined necessary by the department the following baseline water quality provisions apply: (A) the applicant shall submit sufficient and credible baseline water quality information for the receiving water in order for the department to determine the applicable tier protection level and the assimilative capacity of the receiving water, including the capacity to accommodate future development activities or multiple discharges;(B) the level of baseline water quality data necessary for department review must be relative to the size of the project, characteristics of the proposed discharge, and the characteristics of the receiving water including special management or habitat designations, as applicable; and(C) when evaluating whether the information submitted is sufficient and credible or whether additional information may be required, the department will consider all relevant factors, including (i) the sensitivity of the receiving water to degradation of existing or designated uses;(ii) the types of parameters of concern in the proposed discharge;(iii) the available dilution or assimilative capacity of the receiving water for the proposed discharge, including the impacts of authorized discharges;(iv) representativeness of any surrogate water information proposed for baseline water quality relative to the receiving water under review, including geographic, hydrologic, geologic, water use, and water quality characteristics;(v) the validity of any baseline concentrations assumed to be below detection levels;(vi) the quantity, date of analysis, analytical method, detection level, and spatial and temporal scope of any submitted data; and(vii) whether the data considers applicable seasonal or natural variability.