Conduit
Type |
Minimum |
Normal |
Maximum |
Brass, smooth: |
0.009 |
0.01 |
0.013 |
Steel: |
|
|
|
Lockbar and welded |
0.01 |
0.012 |
0.014 |
Riveted and spiral |
0.013 |
0.016 |
0.017 |
Cast Iron: |
|
|
|
Coated |
0.01 |
0.013 |
0.014 |
Uncoated |
0.011 |
0.014 |
0.016 |
Wrought Iron: |
|
|
|
Black |
0.012 |
0.014 |
0.015 |
Galvanized |
0.013 |
0.016 |
0.017 |
Corrugated Metal: |
|
|
|
Sub-drain |
0.017 |
0.019 |
0.021 |
Storm drain |
0.021 |
0.024 |
0.03 |
Cement: |
|
|
|
Neat Surface |
0.01 |
0.011 |
0.013 |
Mortar |
0.011 |
0.013 |
0.015 |
Concrete: |
|
|
|
Culvert, straight and
free of debris |
0.01 |
0.011 |
0.013 |
Culvert with bends,
connections, and some debris |
0.011 |
0.013 |
0.014 |
Finished |
0.011 |
0.012 |
0.014 |
Sewer with manholes,
inlet, etc., straight |
0.013 |
0.015 |
0.017 |
Unfinished, steel form |
0.012 |
0.013 |
0.014 |
Unfinished, smooth wood
form |
0.012 |
0.014 |
0.016 |
Unfinished, rough wood
form |
0.015 |
0.017 |
0.02 |
Wood: |
|
|
|
Stave |
0.01 |
0.012 |
0.014 |
Laminated, treated |
0.015 |
0.017 |
0.02 |
Clay: |
|
|
|
Common drainage tile |
0.011 |
0.013 |
0.017 |
Vitrified sewer |
0.011 |
0.014 |
0.017 |
Vitrified sewer with
manholes, inlet, etc. |
0.013 |
0.015 |
0.017 |
Vitrified Sub-drain with
open joint |
0.014 |
0.016 |
0.018 |
Brick: |
|
|
|
Glazed |
0.011 |
0.013 |
0.015 |
Lined with cement mortar |
0.012 |
0.015 |
0.017 |
Sanitary sewers coated
with sewage slime with bends and connections |
0.012 |
0.013 |
0.016 |
Paved invert, sewer,
smooth bottom |
0.016 |
0.019 |
0.02 |
Rubble masonry, cemented |
0.018 |
0.025 |
0.03 |
|
|
Chow, V.T. (1959). Open-Channel Hydraulics. McGraw-Hill. |
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