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Hydraulics Engineering

 

Hydraulics Engineering - Errata for HEC-18, HEC-20, and HEC-23

(As of September 6, 2001)

HEC-18 (Fourth Edition)

p. xii Definition of ks:

ks = Grain roughness of the bed, m (ft). Delete: "Normally taken as the D84 of the bed material."


pp. 2.8 and 2.9 Delete last sentence p. 2.8 which continues on p. 2.9 that reads "If the magnitude of the 500-year flood is not available from a published source, use a discharge equal to 1.7 times the Q100" and substitute the following:

"For guidance for a particular state in determining the magnitude of the 500-year flood, contact with the U.S. Geological Survey Water Resources District office is suggested."


p. 5.15 Example Problem 3, y2 equation:

Add a close parenthesis so denominator reads (0.0003)2/3 (91.4)2


p. 6.1 First paragraph, 3rd line should read:

"...cohesive or noncohesive..."


p. 6.4 Definition of K4:

Delete ..."and Table 6.4."


p. 6.6 Last sentence in bold should read:

The minimum value of K4 is 0.4.

Delete: "and it should only be used when V1 < Vic D50."


p. 6.7 Equations 6.9 and 6.10:

F should be Fr1


p. 6.13 Equation 6.14: Ks in numerator and denominator should be ks

Definition of ks should read:

ks = Grain roughness of the bed (normally taken as the D84 for sand size bed material and 3.5 D84 for gravel and coarser bed material, m (ft)


p. 6.23 Last paragraph, first sentence should read:

"The angle of repose of cohesionless material..."


p. 6.28 Equation:

"1n" in numerator and denominator should be "ln."

"Ks" in denominator should be "ks."


p. A.9 Appendix A, Table A.7:

For the Kinematic viscosity column, the values should be multiplied by 10-5 not 10-4.


p. E.3 Appendix E, title should be:

Sturm Abutment Scour Equations


pp. E.4 - E.7 Throughout the Appendix: The subscript "o" should be "0" (zero), i.e. "Yfo" should be "Yf0"

The subscripts "l" and "i" should be "1" (one) i.e., "Vml" should be "Vm1" and "Vmic" should be "Vm1c"


p. E.5 Second paragraph, 5th line should read:

"the denominator in the above equation..."


p. E.6 Item 6c: First line should be:

"Compute the critical velocity..."


p. E.7 Item 8a:

Under "where:" change the "xa" in the equal to less than expression to "Xa"

Item 9 should read:

"...scour depth, ys, from Equation E.1."

Item 10, last paragraph, last line should read:

"equation presented in Section E.3."


p. E.8 Reference #2, second line:

Delete "September" and add "FHWA Report No. FHWA-RD-99-156, McLean, VA."


p. F.3 First paragraph, second line should read:

"The equations and method are presented..."



HEC-20 (Third Edition)

p. xi Definition of small greek letter rho:

small greek letter rho = Density of water, kg/m3 (slugs/ft3)


p. 6.15 Definition of ks should read:

ks = Grain roughness usually taken as 3.5 D84 for gravel and coarser bed material, m (ft)


p. 8.4

Reference #46 should read: 46. "Leopold, L.B. and ..."


p. A.9 Appendix A, Table A.7:

For the Kinematic viscosity column, the values should be multiplied by 10-5 not 10-4.



HEC-23 (Second Edition)

p. ix Definition of small greek letter rho:

small greek letter rho = Fluid density, kg/m3 (slugs/ft3)


p. 7.17 Figure 7.11 Flexible Conduit description should read:

"l" UV RESISTANT RUBBER HOSE"


p. 8.4 Reference #46 should read...

46. ..."Geosynthetic Design and ..."

The same change should be made to this reference in:

DG1, p. DG1.16
DG3, p. DG3.6
DG4, p. DG4.23
DG6, p. DG6.27
DG7, p. DG7.9
DG12, p. DG12.21


p. DG6.3 Title of Design Guideline 6 should read:

Concrete Armor Units


p. A.9 Appendix A, Table A.7:

For the Kinematic viscosity column, the values should be multiplied by 10-5 not 10-4.

 
Updated: 06/10/2014
 

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