FLOOD06100

• County: Statewide
• Community: State of Colorado
• Basin: Statewide
• Title: Design of Stable Channels with Flexible Linings
• Date: 10/1/1975
• Prepared By: Hydraulics Branch, Federal Highway Adminstration
• Floodplain - Doc Type: Educational/Technical/Reference Information

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Short Bend Procedure

1. Determine the design depth of flow, d, in the straight
channel.xeach.

2.

2
V /Rd.
11/ !!. or
c

From Chart 33, obtain K3 based on the ratio

3.

I
From Chart 34, obtain K, based
obtain K3 from the equaUon

on the ratio

I
K = 1 + [(K - 1) ~ ]
3 3 I>c

4.

The adjusted depth of flow, d d" for which the lining
t a J
must be designed is K3 times the design depth of flow

for the straight reach.

d = K' (d)
adj 3 straight

5.

Determine lining and/or rock size for d , slope, and
adi
soil erodibility from the Maximum Permissible Depth Charts.

For the condition where both the sides and the bottom of the channel
are to be protected and the channel is narrow ( width to depth ratio
less than 10), additional protection should be provided Ior all surfaces.
For the condition of wide rivers ( width to depth ratio greater than
10) where only the banks are to be protected, generally only the
outside bank of the bend should have additional protection. This
increased protection should extend both upstream and downstream from
the points of curvature to a point where near uniform flow conditions
occur in the channel. For very sinuous, high velocity channels where
waves can be diverted across the channel to the inside bank or where
return of overbank flow can create scour problems, both banks
(inside and outside) should have additional protection.

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