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Constructed Waterway Designer

Products > PC- Convey > Guided Tour

The  CWD uses the following terms:

  • The Main/Low Flow Channel (M/LFC) is the part of the cross-section that carries the low flow (often a 3 month flow).
  • The Main Waterway is the cross-section that carries a larger flow (often the 1% Annual Exceedance Probability discharge) plus an allowance for freeboard.

Features of the Constructed Waterway Designer:

  • Because in reality the Main/Low Flow Channel (M/LFC) can have a flatter grade than the Main Waterway (due to sinuosity of the M/LFC within the Main Waterway) the CWD can use one grade for the M/LFC and another for the Main Waterway, within the same cross-section.

  • The CWD uses the M/LFC grade to determine the dimensions required for the M/LFC to carry its required discharge (e.g. a 3 month or 1 year discharge) and then uses the Main Waterway grade to determine the dimensions required for the Main Waterway to carry its discharge (e.g. a discharge having an Annual Exceedance Probability of 1%).

  • The shear stresses on the cross-section can be checked from the Constructed Waterways Designer, and if they are too high, new batter slopes, bench widths etc. can be tried.

  • The total width of the cross-section can be checked so that you know whether the current design fits in the available space.

  • The freeboard can be varied (normally either 600mm or 300mm).

  • Each Segment of the cross-section can have its own Manning's n value.

Once the input data has been entered you can check the shear stresses from the CWD screen (see next page) then return to this screen to make any adjustments necessary.

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