Abstract: Fluid runoff systems, methods, and apparatus for processing fluid runoff are provided. In one implementation, a base plate for receiving an inlet casting at a drain basin may be provided. The base plate may include a flat surface with an aperture and an outside edge surrounding the flat surface; a raised lip may surround the outside edge and a flange may extend in a horizontal direction away from the raised lip. The flange may define a flat surface for an inlet casting. The base plate may further include one or more sets of tabs located on the underside of the plate. In another implementation, a fluid runoff system may comprise an inlet casting, a base plate, a drain basin, and a pipe. The base plate may include one or more sets of tabs for connecting with the drain basin.