35 Ill. Adm. Code 503.102
Irrigation Activities
Section 503
Section 503.102Â Irrigation
Activities
NPDES permits are required for
discharges of irrigation return flow (such as tailwater, tile drainage,
surfaced groundwater flow or bypass water) operated by public or private
organizations or individuals if:
a)Â Â Â Â Â Â Â Â There is a point source of discharge (e.g., a pipe, ditch or
other defined or discrete conveyance, whether natural or artificial); and
b)Â Â Â Â Â Â Â Â The return flow is from land areas of more than 3000
contiguous acres, or 3000 noncontiguous acres which use the same drainage
system.