Hec-Ras is an excellent public domain backwater computation program written by the US Army Corps of Engineers. Hec-Ras requires considerably more data input than PC-Convey.
You can combine your PC-Convey data files in a form which can be imported into the Hec-Ras program. This enables you to use PC-Convey's powerful editing features to design a cross-section which will carry the required discharge, and then use Hec-Ras to examine the effects of adding a bridge, culvert, weir or encroachment. It is also sometimes useful to compare the results obtained from 2 different programs.
PC-Convey can also be used to calculate the starting water surface level for Hec-Ras runs, or just to simplify the creation of Hec-Ras cross-sections.
To use this feature, you input the discharge information (if it is known) using the Discharge Information screen shown on the previous page of this guided tour, and then specify the additional data shown below:
When you enter the discharge information, PC-Convey calculates the starting water surface level, and composite Manning's n values (for the overbanks and main channel) based on the level to which the flow will rise. The discharge information, starting water surface level and composite Manning's n values are all entered in the appropriate places in Hec-Ras when the file is imported into that program.
You can create a single Hec-Ras cross-section and append other PC-Convey cross-sections to it, or you can append multiple cross-sections with inverts increasing by a user-specified amount. You can also increase the Reduced Levels of all of the cross-section Points by a fixed amount, which can be used to assist the creation of Hec-Ras files when you have a constant grade.
PC-Convey's Help contains more information on how to use the Hec-Ras functions of PC-Convey, as well as examples that use sample files provided with PC-Convey.
This concludes the guided tour of PC-Convey.