Brick floor sloping south within space I-9, for the purpose of letting water flow to southern end of basin and the drain set into this southern wall. It was possibly meant to hold water in the basin, but without mortar between the cracks this seems unlikely. There also appears to be hollow space under the floor (based on sound), possibly due to erosion caused by the water seeping through. Thus, perhaps this SU functioned more as the bottom of a gutter draining rainfall away from the walls of a structure, in which case holding the water inside would not have been essential. The substantial slope would also seem to indicate this kind of a function. The bricks may also represent a repurposed floor, with walls built later to form this basin, as the limits of the SU extend beneath the preserved signinum and, perhaps, the walls.