Enhanced Channel Design Version 1.0
The Enhanced Channel Design spreadsheet tool and User Guidance Manual is provided as an aid to conservationists working on the design of open channels. The tool allows the user to input surveyed field data for an existing channel reach and utilizes concepts and theory from the fields of fluvial geomorphology, hydrology, and open channel hydraulics to evaluate potential alternatives to the traditional open channel design approach, which results in an incised trapezoidal geometry.
These alternatives include the two-stage and self-forming channel design approaches, which attempt to reconnect the channel to an active floodplain. These designs are by no means the only options available for managing channels, but they are the focus of this spreadsheet tool and guidance.
Prior to entering the design phase, an assessment of the project reach, its watershed, and the drainage network upstream and downstream of the site should be conducted to determine whether a two-stage or self-forming channel is an appropriate management approach.
The spreadsheet tool includes some common analytical methods that have been used to design two-stage and self-forming channels in low-gradient, low-energy channel systems typical of the Midwestern United States. However, the tool does not include all of the methods that might be needed to design a successful project, just some common methods that are widely used in practice.
Site specific characteristics and circumstances may dictate that other methods that are beyond the capabilities of this tool are necessary and it is the responsibility of the designer to ensure that appropriate methods are employed and that risk and uncertainty are considered in the development of a design. For example, the level of design needed for a channel in a low-gradient agricultural setting in a rural area may differ from design requirements for a similar channel in a suburban setting. Many times these requirements will vary depending on local, state, and federal regulations and the requirements of authorities that administer programs that permit work in channels.