Illinois Administrative Code
Title 35 - ENVIRONMENTAL PROTECTION
Part 375 - COMBINED SEWER OVERFLOW EXCEPTION CRITERIA AND FIRST FLUSH DETERMINATION
Subpart D - FIRST FLUSH DETERMINATION
Section 375.404 - Modeling

Universal Citation: 35 IL Admin Code ยง 375.404

Current through Register Vol. 48, No. 38, September 20, 2024

a) If all of the overflow locations to be studied cannot be sampled and monitored, or field conditions were not available through direct field measurement as described in Section 375.403, then other methods, including modeling of section(s) of the study area, shall be required to determine first flush. These methods should be used to:

1) Predict the quality and quantity of loads and concentrations.

2) Identify significant sources.

3) Analyze hydraulics of the tributary system.

b) Data supplied for the modeling must be based on factors particular to a given system or study area and should include:

1) Rainfall data

2) Size of drainage area

3) Land use

4) Population density

5) Hydraulics of area

6) Percentage of combined and/or separate sewers

c) The type of modeling to be used for a given collection system or study area shall be addressed in the Plan of Study for the CSO Analysis. References, such as textbooks, technical papers, etc., for the modeling methods to be used shall be listed.

d) Verification that the model(s) is valid shall be provided by comparing the output obtained from the model(s) with actual sampling and monitoring data from overflow points specified in accordance with Section 375.403 for two or more storms.

Disclaimer: These regulations may not be the most recent version. Illinois may have more current or accurate information. We make no warranties or guarantees about the accuracy, completeness, or adequacy of the information contained on this site or the information linked to on the state site. Please check official sources.
This site is protected by reCAPTCHA and the Google Privacy Policy and Terms of Service apply.