FLOOD09911

• County: Statewide
• Basin: Statewide
• Title: Culvert Design
• Date: 8/1/2000
• Prepared By: Ayres Associates
• Floodplain - Doc Type: Educational/Technical/Reference Information

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Lesson 4

Demonstration and Problem Session - Participant Workbook

4.1 DEMONSTRATION OF FLOW IN A CULVERT

Purpose:

To use the demonstration flume to illustrate outlet control, inlet control, and the
effect of inlet type on culvert flow.

A. Outlet Control Demonstration

Outlet control conditions will be demonstrated with the double-barrel culvert
insert in the demonstration flume. With the flume on a zero percent slope, the
discharge will be increased to create full flow conditions in the pipe, with a low
tailwater condition. The factors influencing outlet control will be evaluated and
discussed during the demonstration.

NOTES:

B. Inlet Control Demonstration

Inlet control conditions will be demonstrated by increasing the flume slope.
Under inlet control a free surface condition exists in the culvert barrel. Notice
that initially, as the slope increases, the headwater remains constant and the
culvert continues to operate in outlet control. However, eventually the
headwater begins to increase and a free surface condition develops,
indicating a change to inlet control. In the field, inlet control can occur at
about a half of one percent slope for a smooth barrel.

The effect of inlet condition will be demonstrated with the single barrel culvert
model. The changes in headwater for a sharp edge, miter, thick wall,
headwall, groove end, headwall with a bevel, and side- and slope-tapered
inlets will be demonstrated.

NOTES:

4-3