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United States Department of Agriculture
Natural Resources Conservation Service

2118 W. Park Court, Champaign, IL 61821
Phone: 217/353-6600 Fax: 217/353-6676 Website:

DATE: October 24, 2007

SUBJECT:  National Engineering Handbook Part 645, Engineering Technical Materials

Purpose:  To update Illinois Supplements to the Engineering Field Handbook, Chapters 1 and 2

Expiration Date:  Upon receipt.

Explanation: This notice is to inform you that the Illinois supplements to the Engineering Field Handbook (EFH) are being digitized for online posting. In addition to the digitizing process, updates are being made to the supplements as needs are identified.

Illinois supplements to the EFH are now complete in digital form for the following chapters:

  • Chapter 1 – Engineering Surveys
  • Chapter 2 – Estimating Runoff and Peak Discharges

The following list outlines the updated Illinois supplements, released with this notice, along with the supplements that have been retired as obsolete. The table of contents for Illinois EFH supplements will be updated when all chapters are complete.

Existing IL supplement: Replaced by:
2-10.1 through 2-10.8 Soil Series in Illinois 2-42.1 through 2-42.8 Soil Series in Illinois
2-10.9 through 2-10.14 Hydrologic Soil Groups 2-42.9 through 2-42.16 Hydrologic Soil Groups
2-30.1 and 2-30.2 Runoff Curve Numbers Obsolete (now exists in national EFH Table 2-3)
2-36.1 Index of Sheets -Rainfall, Base Flow and Other Maps 2-36.1 Index of Sheets – Rainfall and Other Maps
2-36.2 Design Base Flow Obsolete
2-36.3 100 year – 6 hour rainfall 2-36.3 (updated to Bulletin 70)
2-36.4 through 2-36.7 ES and freeboard hydrographs Obsolete
2-36.8 through 2-36.13 Rainfall maps – 24 hr duration 2-36.8 through 2-36.13 (updated to Bulletin 70)
2-36.14 through 2-36.17 Rainfall and Tc maps Obsolete
2-50.1 through 2-50.14 Rainfall-Runoff Depths Obsolete
IL 2-77, 2-79 and 2-80 Sample Runoff Computation Obsolete (IL-ENG-26 is also now obsolete as a result)

The Illinois NRCS engineering website will be revised to include a link to the digital versions of the Illinois supplements to the Engineering Field Handbook. Supplements for Chapters 1 and 2 will be posted at this time.

Filing Instructions:

All holders of Engineering Field Handbook binders should:

  1. Remove all Illinois supplements which have been updated or identified as obsolete from the EFH.
  2. Print out the attached updated supplements on green paper and file in the EFH as identified on the above table. Illinois supplements are numbered to correspond to the page number of the national EFH, and are filed directly after the national page with the same base number.

Any questions regarding this submittal should be directed to Ruth Book, State Conservation Engineer at (217) 353-6626.

Ruth Book Signature
State Conservation Engineer

Field Offices (with attachments)
Engineers (with attachments)


This attachment requires  Adobe Acrobat Reader to view: 
EFH-Ntc29_102407.pdf  [PDF, 90kb]

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