Overview
Roadside channels play an important role in the highway drainage system as the initial conveyance for highway runoff. Roadside channels capture sheet flow from the highway pavement and backslope and convey that runoff to larger channels or culverts within the drainage system. This initial concentration of runoff may create hydraulic conditions that are erosive to the soil that forms the channel boundary. To perform reliably, the roadside channel is often stabilized against erosion by placing a protective lining over the soil.
Channel lining materials fall into two classes: rigid or flexible channel linings. From an erosion control standpoint, the primary difference between rigid and flexible channel linings is their response to changes in channel shape (i.e. the width, depth and alignment). Flexible linings are able to adjust to some change in channel shape while rigid linings cannot. The ability to sustain some change in channel shape improves the overall integrity of the channel lining and reduces maintenance. Movement of a rigid lining at one location can result in a successive failure of the lining. Channel lining materials often experience forces such as frost heave, slumping or swelling of the underlying soils that can change the shape of the lining. These forces can displace rigid linings whereas flexible linings, if properly designed, will retain erosion-control capabilities.
This is the first part of a two-part course based on U.S. Department of Transportation, Federal Highway Administration, National Highway Institute Publication No. FHWA-NHI-05-114, Design of Roadside Channels with Flexible Linings (Hydraulic Engineering Circular No. 15, Third Edition, September 2005).
Part 1 covers chapters 1 through 4. The target audience is highway and hydraulic engineers with an interest in controlling stormwater runoff and channel erosion. To receive PDH credit for the course, the reader must pass a multiple-choice quiz consisting of twenty (20) questions.
Specific Knowledge or Skill Obtained
This course teaches the following specific knowledge and skills:
- Knowing fundamental differences between flexible and rigid channel linings
- Distinguishing among types of flexible linings
- Understanding design concepts for flexible linings such as open channel flow, shear stress, and various design parameters
- Applying basic design procedure for straight channels, with both single and composite linings
- Applying design procedure to channel bends to account for shear stress and freeboard
- Understanding the maximum discharge approach
- Understanding design procedures for both vegetative and bare soil linings
Course
Click on the following link to the PDF document to review the course material before taking the quiz for credit.
Design of Roadside Channels with Flexible Linings Part 1
Having trouble downloading the PDF file?
If clicking the link does not bring you to the PDF file, then right-click the link. Click "Save Target As" and save on your desktop. To view the file, double-click the icon on your desktop and return to this page to take the quiz. You may want to bookmark this page for your convenience. If you have questions, Live Support Chat can help.
You
may need Adobe Reader to view this document. Click on the link to
download a free copy of the latest version of Adobe Reader.
To receive PDH credit for this course, you must pass a multiple-choice quiz. Click the button below to Purchase Course and Take Quiz. To take the quiz, your computer must be set to accept cookies. See how to check your cookie settings.
