Flow Path lines are used to compute reach lengths between cross sections in the left and right overbank. Flow path lines are created in the downstream direction following the center-of-mass of flow in the left and right overbanks (it is not necessary to create a flow path in the main channel). They should be drawn in the direction of flow, never intersect river lines and only intersect a cross section line once. Flow path lines should be constructed prior to creating Cross Section locations to assist the user in laying out cross sections perpendicular to flow.
For existing model data, flow path line can be auto-generated base on the shape of the river centerline and cross section layout. Right-click on the Flow Paths Layer and select Create Flow Paths from XS Layout. Lines will be created in the overbank areas based on on 1/3 of the distance from the bank stations to the ends of the cross section and will be shaped based on the river. These lines will not be reflect the Reach Lengths defined on each cross section; they are only an initial geospatial estimate to assist users with a a starting point and must be edited by the user to connect the expected center-of-mass of flow from cross section to cross section.