CONCRETE PIPE Defining Catch Basins A catch basin (CB) is an inlet device that collects stormwater offline of a storm system, and conveys this flow to the system. A catch basin is typically of a smaller diameter than a manhole and is buried at shallower depths. Most often, a catch basin is located along a curb or low spot and topped with an open grate to facilitate stormwater capture. The following presents an assorted glossary of common catch basin terms. Benching – refers to the channels constructed within the base of a manhole to convey flow. Pre-benched (PB) Manhole – a manhole that has been manufactured with the benching already in place. Otherwise, the benching is installed in the field. Monolithic Base – A monolithic manhole base refers to a single piece of concrete that consists of both a base and barrel walls. Pre-Benched manholes are by nature monolithic bases. Flat Base Manhole – A manhole with no benching in place, typically used to provide a sump. Can be monolithic or consist of separate materials. Weeping (Weeper) Holes – weeping holes are typically installed in the walls of catch basin material to avoid flooding. The holes allow stormwater to infiltrate into the surrounding groundwater if the water level rises above a certain level within the basin. Inlet Control Device (ICD) – an ICD is a solid metal plate that is placed directly over an opening in a manhole and contains a smaller opening to limit the flows entering or exiting the manhole. PAGE 6 LAFARGE PIPE eMANUAL