The director shall, in consultation with the appropriate basin advisory group, identify reference streams or conditions to assist in determining whether the designated beneficial uses of water bodies within a basin are being fully supported. Streams or conditions shall be selected to represent the land types, land uses, hydrology, water uses and geophysical features within the basins described in this chapter. Reference streams or conditions shall be representative of one (1) of the following:

1. (1) A stream or other water body reflecting natural conditions with few impacts from human activities and which is representative of the highest level of support attainable in the basin; or
2. (2) A stream or water body reflecting the minimum conditions necessary to fully support the designated beneficial uses of the stream or water body; or
3. (3) Physical, chemical and biological indicators identified in the rules of the department which reflect full support of designated beneficial uses.

[39-3605, added 1995, ch. 352, sec. 1, p. 1171; am. 1997, ch. 279, sec. 3, p. 833; am. 2013, ch. 348, sec. 3, p. 945.]