A junction is an element with one or more inflows and only one outflow. All inflow is added together to produce the outflow by assuming zero storage at the junction. It is usually used to represent a river or stream confluence.
The junction element does not have any special data or properties; it only has the standard Component Editor used by all elements. Access the Component Editor by clicking the junction element icon on the "Components" tab of the Watershed Explorer (see figure below). You can also access the Component Editor by clicking on the element icon in the basin map, if the map is currently open.
Junction component editor.