Ill. Admin. Code tit. 35 § 301.373
"Same Body of Water" means that, for purposes of evaluating intake toxic substances consistent with 35 Ill. Adm. Code 352.425, the Agency will consider intake toxic substances to be from the same body of water if the Agency finds that the intake toxic substance would have reached the vicinity of the outfall point in the receiving water within a reasonable period had it not been removed by the permittee and there is a direct hydrological connection between the intake and the discharge points. Despite the provisions of this definition, an intake toxic substance will be considered to be from the same body of water if the permittee's intake point is located on Lake Michigan and the outfall point is located on a tributary of Lake Michigan. In this situation, the background concentration of the toxic substance in the receiving water must be similar to or greater than that in the intake water and the difference, if any, between the water quality characteristics of the intake and receiving water must not result in an adverse impact on the receiving water.
Ill. Admin. Code tit. 35, § 301.373
Added at 23 Ill. Reg. 11277, effective August 26, 1999