Bank Lines are used to define the main channel banks for a cross section. If the bank lines are not defined, the bank stations will be set to the ends of the cross sections. Banks lines may be drawn continuous or discontinuous, in either the downstream or upstream direction, but it is suggest that you have a left and right bank line for each river line. Make sure the bank lines don’t intersect the river lines or each other and only cross a cut line once.
For existing model data, bank lines can be auto-generated from bank stations by from a right-click on the Bank Lines layer and selecting the Create Bank Lines from XS Bank Stations menu item. Another option to Pull Bank Lines to Bank Stations is available once a user has set bank stations in the Cross Section Editor and wants the Bank Lines layer to snap to those bank stations.