I am trying to model stormwater retention basin for a site that is very flat (in south louisiana) and has very limited property available for a retention basin. So my thought is to use the ditches as the retention basin and have a weir at the end. I also plan to use a pump to empty the ditches with water below the weir outlet elevation and to help keep the ditches from overflowing. But I am having trouble figuring how to model a weir and a pump? Any suggestions? Right now I have my subbasins connected to junctions and the links (ditches) going from junction node to junction node. At the end of the ditch is where I have one storage node with a weir linked to the outfall. However, it tells me my storage node is flooding. Should I make all of my 'junctions' be 'storage nodes' instead? How do I add a pump to help prevent ditch overflow and to empty the ditches with water below the weir outlet elevation?