Catch basins convey surface water into a storm sewer pipe system. A catch basin (a.k.a., storm drain inlet, curb inlet) is an inlet to the storm drain system that typically includes a grate or curb inlet where stormwater enters the catch basin and a sump to capture sediment, debris and associated pollutants. They are also used in combined sewer watersheds to capture floatables and settle some solids.

When you click the catch basin element on the Layout toolbar, your mouse cursor changes into a catch basin element symbol. Clicking in the drawing pane while this tool is active causes a catch basin element to be placed at the location of the mouse cursor.

Bentley SewerGEMS now supports HEC-22 inlet capacity calculations. You can set up inlets (grate, combination, curb opening, etc.) and Bentley SewerGEMS will compute inlet capacity based on flow to the inlet, as well as inlet and gutter geometry.