Primary Layers are created when a watershed is created (Time Series Icons layer); when a stream alignment is created (Stream Alignment layer); when a grid set is created (Gridded Data layer); and, when forecast alternatives and forecasts are created (Modeling Schematic layer). Primary layers are present in all CWMS watersheds (although some layers may be empty in some watersheds) and are foundational to CWMS. This section describes how primary layers are configured and managed. The primary layers are usually listed at the top of the Map Tree within the Map Layers editor, as shown below. For further information on the Map Layers editor, refer to Understanding Layers.
