Source elements provide a way to add measured inflows to the flow network, or to represent upstream boundary conditions. Junction elements are used in the flow network to combine multiple inflows, often at a confluence. The diversion element is used to represent locations in the flow network where water is withdrawn from the channel, and may be discharged to a canal or stream. Finally, sink elements are used to represent the outlet of a watershed. It is permissible to have more than one outlet in a basin model.