Indiana Administrative Code › Title 327 - WATER POLLUTION CONTROL DIVISION › Article 2 - WATER QUALITY STANDARDS › Rule 1.5 - Water Quality Standards Applicable to All State Waters Within the Great Lakes System › Section 1.5-16 - Site-specific modifications to Tier I criteria and Tier II values

Current through July 10, 2024
Authority: IC 13-14-8; IC 13-14-9; IC 13-18-3
Affected: IC 13-15-4-1; IC 13-18-4
Sec. 16.
(a)
				Site-specific modifications to Tier I criteria and Tier II values must be
				protective of designated uses and aquatic life, wildlife, or human health. In
				addition, any site-specific modifications that result in less stringent
				criteria must be based on a sound scientific rationale and shall not be likely
				to jeopardize the continued existence of endangered or threatened species
				listed or proposed under Section 4 of the Endangered Species Act (ESA) or
				result in the destruction or adverse modification of such species' critical
				habitats. More stringent modifications shall be developed to protect endangered
				or threatened species listed or proposed under Section 4 of the ESA, where such
				modifications are necessary to ensure that water quality is not likely to
				jeopardize the continued existence of such species or result in the destruction
				or adverse modification of such species' critical habitats. More stringent
				modifications may also be developed to protect candidate (C1) species being
				considered by the U.S. Fish and Wildlife Service (FWS) for listing under
				Section 4 of the ESA, where such modifications are necessary to protect such
				species. Criteria and values may be modified on a site-specific basis to
				reflect local environmental conditions as restricted by the following
				provisions:
(1) Aquatic life criteria or
				values may be modified on a site-specific basis as follows:
(A) Aquatic life criteria or values may be
				modified on a site-specific basis to provide an additional level of
				protection.
(B) Less stringent
				site-specific modifications to chronic or acute aquatic life criteria or values
				may be developed when either of the following conditions applies:
(i) The local water quality characteristics
				such as pH, hardness, temperature, or color alter the biological availability
				or toxicity of a pollutant.
(ii)
				The sensitivity of the aquatic organisms species that occur at the site differs
				from the species actually tested in developing the criteria.
(C) Less stringent modifications
				also may be developed to acute and chronic aquatic life criteria or values to
				reflect local physical and hydrological conditions.
(D) Any modifications to protect threatened
				or endangered aquatic species required by this subsection may be accomplished
				using either of the two (2) following procedures:
(i) If the SMAV for a listed or proposed
				species or for a surrogate of such species is lower than the calculated FAV,
				such lower SMAV may be used instead of the calculated FAV in developing
				site-specific modified criteria.
(ii) The site-specific criteria may be
				calculated using the recalculation procedure for site-specific modifications
				under
				327
				IAC 2-1-13.