Illinois Environmental Protection Agency Crab Orchard Creek Watershed TMDL
Final Report
San Pat Apartments (S.I. Properties LLC) - permit number ILG551066
M&M Rentals MHP - permit number ILG551017
Manganese loads for these facilities were not calculated because sampling for manganese is not required
by the discharge permits for these facilities and they are not expected to be significant sources of
manganese. Therefore, WLAs of zero were specified for these facilities as part of this TMDL.
Table 14 presents the TMDL summary for segment ND13. The manganese data were collected during
dry flow conditions and only one sample exceeded the threshold limit. An overall reduction of 84 percent
is required during dry flow conditions to meet the water quality standard. Because there are only two
samples available for manganese, it is recommended that future monitoring be conducted to allow for a
more thorough water quality assessment in Crab Orchard Creek segment ND13.
Table 14. Manganese TMDL Summary for Crab Orchard Creek Segment ND13
Station ND02 TMDL High
Flows
Moist
Conditions
Mid-
Range
Flows
Dry
Conditions
Low
Flows
Pollutant TMDL
Component 0-10 10-40 40-60 60-90 90-100
Current Load No Data No Data No Data 172.83 No Data
LA 6403.05 624.69 156.15 27.33 3.90
TMDL=
LA+WLA+MOS 7114.50 694.10 173.50 30.37 4.34
WLA 0 0 0 0 0
MOS (10%) 711.45 69.41 17.35 3.04 0.43
Total
Manganese
(lb/day)
Reduction No Data No Data No Data 84% No Data
Possible sources of manganese loads in segment ND13 may be attributed to natural background
conditions and release of manganese from river bottom sediments.
5.1.5 Loading Capacity of Crab Orchard Creek Segment NDA01
Little Crab Orchard Creek (Segment NDA01) is 12.21 miles long and flows north to segment ND01.
Little Crab Orchard Creek drains approximately 9 square miles and the upstream land use consists of
primarily pasture grassland (28%), deciduous forest (29%), and developed land (27%). Little Crab
Orchard Creek is impaired by manganese. Five manganese samples were available for load duration
analysis, two of which were sampled on 1995, one in 1996 and one in 2006. Existing and allowable loads
were calculated using the load duration curve approach. The manganese water quality standard of 1000
μg/L was used to develop TMDL loads for this segment.
There are three NPDES facilities that are permitted to discharge in Little Crab Orchard Creek:
Lilac Basin Corp - Union Hill (Lilac) - permit number IL0046221
Lenore Basin Corp – Union Hills (Lenore) - permit number ILG551037
Tan Tara 2 Mobile Home Park (TTMHP) - permit number IL0049077
WLAs of zero for these facilities were specified as part of this TMDL because these facilities do not
discharge manganese.
Electronic Documents of Illinois
