East Fork Kaskaskia Watershed TMDL Implementation Plan
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1. INTRODUCTION
The State of Illinois assesses its water bodies for compliance with water quality standards
established to protect their designated uses. This assessment is required by the federal
Clean Water Act. Section 303(d) of the Clean Water Act requires states to identify waters
which will not attain applicable water quality standards with technology-based controls
alone. Water bodies so identified are placed on a 303(d) list and prioritized to have a
Total Maximum Daily Load (TMDL) developed. The TMDL is specific to the water
quality constituent(s) that is in violation of the water quality standard. The TMDL
process establishes the allowable loading of pollutants or other quantifiable parameters
for a water body based on the relationship between pollution sources and in-stream or in-lake
water quality conditions. This allows water quality-based controls to be developed to
reduce pollution and to restore and maintain water quality.
The lower segment of the East Fork Kaskaskia River has been identified as being water
quality limited and is on Illinois’ 303(d) list. Stream segment IL_OK-01 is impaired by
siltation, fecal coliform bacteria, and dissolved oxygen (DO) deficits; stream segment
IL_OK-02 is impaired by DO deficits. A TMDL for the DO and fecal coliform bacteria
impairments was approved by the US EPA in September 2006 (Baetis 2006). The US
EPA approval letter accepted the report’s conclusion that the DO impairments were
attributed to low flow conditions rather than a specific pollutant, and as such, a TMDL
was not required for DO for segments IL_OK-01 or IL_OK-02. This report recommends
approaches to implementing the fecal coliform bacteria TMDL in segment IL_OK-01.
The siltation TMDL and implementation plan was published in 2003 (Harza 2003).
The next step in the TMDL process is to develop an implementation plan for the TMDL
that includes both accountability and the potential for adaptive management. Best
Management Practices for nonpoint sources will strictly be voluntary. Adaptive
management involves the implementation of a long-term monitoring plan designed to
assess the effectiveness of pollution controls as they are implemented, as well as progress
towards attaining water quality standards.
