Rainfall catch basin - with relief sill in centre of bottom cone for water effluent free from solids

摘要

The basin has a gently sloping conical bottom with a steeper central cone in the upward direction in the centre. An annular gutter at the base of the central cone removes grit and other solids. The central relief sill consists of a funnel on top and a vertical relief pipe though the apex of the central cone. This takes away the solid-free overflow water. The arrangement improves the sedimentation of sand and other solids and prevents the formation of solid deposits on the conical basin bottom.