Section 620.230  Class III:  Special Resource Groundwater

Except as provided in Section 620.250, Special Resource Groundwater is as described in subsection (a) or (b):

a)         Groundwater that is determined by the Board, under the procedures specified in Section 620.260, to be:

1)         Demonstrably unique (e.g., irreplaceable sources of groundwater) and suitable for application of a groundwater quality standard more stringent than the otherwise applicable groundwater quality standard specified in Subpart D; or

2)         Vital for a particularly sensitive ecological system.

b)         Groundwater that contributes to a dedicated nature preserve that is listed by the Agency as specified below:

1)         A written request to list a dedicated nature preserve under this subsection must contain the following information:

A)        A general description of the site and the surrounding land use;

B)        A topographic map or other map of suitable scale denoting the location of the dedicated nature preserve;

C)        A general description of the existing groundwater quality at and surrounding the dedicated nature preserve;

D)        A general geologic profile of the dedicated nature preserve based upon the most reasonably available information, including geologic maps and subsurface groundwater flow directions; and

E)        A description of the interrelationship between groundwater and the nature of the site.

2)         Upon confirmation by the Agency of the technical adequacy of a written request, the Agency must publish the proposed listing of the dedicated nature preserve in the Environmental Register for a 45-day public comment period. Within 60 days after the close of the public comment period, the Agency must either publish a final listing of the dedicated nature preserve in the Environmental Register or provide a written response to the requestor specifying the reasons for not listing the dedicated nature preserve.

3)         At least once annually, the Agency must publish in the Environmental Register a complete listing of all dedicated nature preserves listed under this subsection.

4)         For this subsection "dedicated nature preserve" means a nature preserve that is dedicated under the Illinois Natural Areas Preservation Act [525 ILCS 30].

(Source:  Amended at 49 Ill. Reg. 4488, effective March 28, 2025)