SMC maintains a rain gauge network with locations in the Fox River watershed at Antioch, Long Lake, Round
Lake Park, and Wauconda. While the period of record is not as extensive as the data available from the State
Climatologist for Antioch, the data could be of use for model calibration.
Response: Thank you for your comment. Illinois EPA and AECOM will work with SMC in identifying
the appropriate gauges to use in modeling the hydrology.
The report indicates that discharge data for the Johnsburg gauge is available only for the period between 1997
and 1999. SMC recommends contacting IDNR-OWR for possible additional discharge information for the
Stratton Dam. IDNR-OWR calculates discharges for use in the dam operation.
Response: Thank you for your comment. Illinois EPA and AECOM will contact IDNR-OWR concerning
dam operation.
Figure 5-2 depicting the relationship between temperature, depth and dissolved oxygen concentration could be
simplified or reformatted to make it easier to read. It is difficult to show the relationship between 4 variables
(depth, temperature, dissolved oxygen, and date) on a graph with 2 axes. Perhaps using the same color for
temperature and DO data from the same date would make the relationship between these two variables more
apparent.
Response: Thank you for your comment. AECOM will re-evaluate the graph.
The findings of the Center for Watershed Protection report “Impacts of Impervious Cover on Aquatic Systems”
and its associated Impervious Cover Model (e.g., that impairment of waters is common at 25% watershed
impervious cover) are applicable only to 1st, 2nd, and 3rd order streams. While the relationship between
watershed imperviousness and water quality is likely similar in lakes and streams, the model has not been
validated for large rivers or lakes and reservoirs. If findings or information from this report are to be used as
sources of data for model or TMDL development, this is an important consideration. Application of this data to
lakes (or to segment DT-35, which may be larger than 3rd order) may not be scientifically defensible.
Response: The reference to the “Center for Watershed Protection” report was merely used as an
explanation for linking land use to sources of water body impairment. This information will not be
used in the modeling approach.
Under section “6.1.1 Fox River,” combined sewer overflows are listed as a potential source of the fecal
coliform impairment. It would be helpful to verify the locations of any combined sewer systems (in both the
Illinois and Wisconsin portions of the watershed) before any models are developed. There are no known CSO
outfalls in Lake County.
Response: Thank you for your comment. The Stage 3 report will investigate the locations of CSO
outfalls. The Stage 1 report will be updated to note that no known CSOs exist in Lake County.
It was unclear at the public meeting (August 25, 2009) how the model will account for the pollutant loads from
the Wisconsin portion of the watershed. This should be clarified in the Stage 3 report. The Wisconsin land area
tributary to the mainstem Fox River and Nippersink Creek watersheds encompasses over 1,000 square miles
(according to the Wisconsin Department of Natural Resources) and is a mix of agricultural and urban areas.
This is likely a significant source area for loadings entering the Illinois portion of watershed in the TMDL study
area, particularly since Wisconsin accounts for the vast majority of the drainage area tributary to segment DT-
35. The Southeastern Wisconsin Regional Planning Commission (SEWRPC) has provided land use data to
SMC for past watershed plans and should be contacted if this information would benefit the development of
TMDLs. SMC can provide contact information for SEWRPC if needed. It will also be important to coordinate
with Wisconsin DNR, since the TMDL implementation plan will likely require significant actions in the
Wisconsin portion of the watershed to meet the water quality standards for the impaired Illinois segments of
the Fox River and Chain O’ Lakes.
