Hydraulic Design of Highway Culverts - DOT On-Line Publications

Figure VI-20--Fill Warped to Avoid Inlet Skew
Figure VI-21--Double Barrel Box Culvert
There are problems associated with the use of multiple barrel culverts. The most significant
problems involve sedimentation and debris. In alluvial channels, normal flows will tend to pass
through one of the barrels, while sediment and debris collect in the others. To reduce this
problem, it is good practice to install one barrel at the flow line of the stream and the others at
higher elevations (Figure VI-22). This will encourage the flow to follow the lower barrel.
Sediment and debris accumulation in the other barrels will be reduced since the barrels will only
be used to convey higher than normal flows.
The nomographs of this publication can be used to determine the capacity of multiple barrel
culverts with only minor alterations. The nomographs provide the culvert discharge rate per
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