Hydraulic Efficiency of Grate and Curb Inlets - Urban Drainage and ...

2 LITERATURE REVIEW
Urban storm drainage is an extensive topic that can range in scope from application of
BMPs at a system level, to analysis of any given component in a large drainage network. Inlets
tested in this study are used at the component level. The scope of this literature review is to
provide background necessary for use of the collected test data in developing improved design
methods. This chapter describes the model utilized to supply data for development of current
UDFCD design methods for grate and curb inlets. Current design methods are explained and
equations are presented from the USDCM. Two velocity-depth numerical relationships
commonly known as Manning’s equation and the Froude number are defined. The dimensional
analysis method, which is commonly used for developing equations to predict observed test data,
is explained.
2.1 Relevant Street Drainage Studies
HEC 22 was developed, in part, from a FHWA report titled “Bicycle-safe Grate Inlets
Study.” Ultimately, it was that FHWA study that provided data for development of the inlet
equations provided in HEC 22 and used in the USDCM for the Type 13 and 16 inlets. Volume 1
of the FHWA study titled “Hydraulic and Safety Characteristics of Selected Grate Inlets on
Continuous Grades” (FHWA, 1977) describes the model built and the testing methods used.
Table 2-1 provides a summary of physical characteristics of the FHWA model.
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