HY8:Inlet Depression

The fall or depression of a culvert is the vertical drop of the inlet control section below the stream bed. An inlet depression is defined by entering a value for each of the following items (see drawing below):

• Depression
• Fall Slope
• Crest Width

DEPRESSION

The vertical drop of inlet control section below the stream bed.

FALL SLOPE

Slope between the stream bed and the face invert. The fall slope must be set between 2:1 and 3:1.

CREST WIDTH

Length of weir crest at the top of the fall slope. Designing the crest width becomes an iterative process in HY-8 as the user must select a crest width wide enough so that it does not control the headwater calculations. If the selected crest width is not wide enough the crest section will produce a higher headwater elevation than the culvert throat. The user must continue to increase the crest width and run the analysis until the headwater depth ceases to change with increasing crest width. Once this occurs the crest section no longer controls and may be used in analysis and construction.

Related Topics

Introduction

• Introduction

Culvert Data

Culvert Data

• Culvert Data
• Shapes
• Material
• Plastic Pipe Materials
• Concrete Open-Bottom Arch
• Inlet Type
• Inlet Edge Conditions
• Inlet Depression
• Embedment Depth

Site Data

• Site Data Input Option
• Culvert Invert Data
• Embankment Toe Data