HEC 22 - Urban Drainage Manual

Changes from Second Edition

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• Page 3-11, Example 3-2, The solution to this example has been revised.
• Page 3-14, Table 3-4 - Table of manning's n values has been updated.
• Page 3-16, Section 3.2.3 - The reference to the USGS National Flood Frequency program has been changed to National Streamflow Statistics program, NSS.
• Chapter 4 - Several references to Appendix C were revised to Appendix B. pages 4-15, 4-26, 4-45,
• Page 4-83 - Equation 4-39 has been corrected.
• Page 5-4 - Section 5.15 has been re-titled to Manning's Equation and the text has been updated.
• Page 5-5 - Table 5-1 has been updated to reflect values provided in the new HEC 15 publication. Former Tables 5-2 and 5-3 have been eliminated.
• Page 5-6 - Example problem 5-1 has been updated to reflect the new procedures in HEC 15.
• Page 5-7 - Section 5.1.7 has been changed to Shear Stress and Figure 5-4 has been revised.
• Page 5-10 - Example problem 5-2 has been updated to reflect the new procedures in HEC 15.
• Page 5-13 - Section 5.3 has been changed to Stable Channel Design.
• Page 5-13 - Section 5.3.1, Lining Materials, has been added.
• Page 5-14 - Section 5.3.2, Stable Channel Design Procedure has been added to replace the previous Section 5.3, Design Procedure.
• Page 7-3 - Chart 25 in the first line was changed to Chart 23 and Chart 26 in the first line after Figure 7-1 was changed to Chart 24.
• Page 7-5 - Three references to Chart 25 were changed to Chart 23.
• Page 7-6 - Three references to Chart 25 were changed to Chart 23.
• Page 7-16 - Table 7-5 was updated.
• Page 7-16 - Section 7.1.6.7 has been totally revised to reflect a new methodology for calculating energy losses in access holes.
• Section 7.1.6.8 has been eliminated.
• Page 7-34 - Section 7.5, the energy gradeline computational procedure has been completely changed to reflect the new energy loss methodology.
• Page 7-37 - Figure 7-10, Energy Grade Line Computation Sheet - Table A has been revised.
• Page 7-38 - Figure 7-11, Energy Grade Line Computation Sheet - Table B has been revised.
• Page 7-44 - Section 7.6, Example Problem 7-3 (SI and English versions) has been updated for the new energy loss methodology.
• Appendix A - Former Charts 23 and 24 (permissible shear stress for cohesive and non-cohesive soils) have been removed. The remaining Charts have been renumbered accordingly.
• Appendix C - References have been updated.