FINAL APPROVED TMDL SEPTEMBER 2005
Highland Silver Lake (ROZA)
Limno-Tech, Inc. Page 14
The guidelines also state that the public water supply use is not supported if, in untreated
water, greater than 10% of the observations exceed the applicable standard, for water
samples collected in 1999 or later, and for which results are readily available. The
available data confirm that the listing of Highland Silver Lake for manganese is
appropriate based on IEPA’s guidelines.
4.2.2 Total Phosphorus
The IEPA guidelines (IEPA, 2004b) for identifying total phosphorus as a cause in lakes
(for lakes > 20 acres) state that the aquatic life use and the secondary contact use are not
supported if the surface phosphorus concentration exceeds the applicable standard (0.05
mg/l) in at least one sample during the monitoring year. The available data support the
listing of phosphorus as a cause of impairment in Highland Silver Lake.
4.2.3 Dissolved oxygen
The IEPA guidelines (IEPA, 2004b) for identifying dissolved oxygen as a cause in lakes
state that the aquatic life use is not supported if there is at least one violation of the
applicable standard (5.0 mg/l minimum; 6.0 mg/l average) at one foot depth below the
lake surface; or a known fish kill resulting from dissolved oxygen depletion. The
available data support the listing of dissolved oxygen as a cause of impairment in
Highland Silver Lake.
4.2.4 Aldrin
The IEPA guidelines (IEPA, 2004b) for identifying aldrin as a cause in lakes state that
the fish consumption use is not supported if there is a fish consumption advisory or
commercial fishing ban in effect, attributable to any applicable parameter (e.g., aldrin).
Furthermore, the public water supply use is not supported if, in untreated water, greater
than 10% of the observations exceed the applicable standard for water samples collected
in 1999 or later and for which results are readily available. Finally, the aquatic life use in
inland lakes is not supported if aldrin in the sediment is found at highly elevated
concentrations. The available data confirm that the listing of Highland Silver Lake for
aldrin is appropriate based on IEPA’s guidelines.
4.2.5 Chlordane
The IEPA guidelines (IEPA, 2004b) for identifying chlordane as a cause in lakes state
that the fish consumption use is not supported if there is a fish consumption advisory or
commercial fishing ban in effect, attributable to any applicable parameter (e.g.,
chlordane). Furthermore, the public water supply use is not supported if, in untreated
water, greater than 10% of the observations exceed the applicable standard for water
samples collected in 1999 or later and for which results are readily available. The
available data confirm that the listing of Highland Silver Lake for chlordane is
appropriate based on IEPA’s guidelines.
