Hydraulic Design of Highway Culverts - DOT On-Line Publications

Figure IV-8--Performance Curves for 6 ft by 6 ft Box Culvert
with 90-degree Wingwall
Performance curves provide a basis for the selection of the most appropriate culvert design. For
example, culvert designs with and without tapered inlets can be compared and evaluated using
performance curves (Figure IV-8).
Performance curves are useful in optimizing the performance of a culvert. By manipulating the
depressions of the face and throat sections, it is often possible to achieve a higher flow rate for
a given headwater elevation, or to pass the same flow at a lower headwater. A more detailed
description of the use of performance curves in improved inlet design is presented in Appendix
C.
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