ABSTRACT
Stormwater is removed from the streets through inlets. Inlets are placed at low points, highway median breaks, and street intersections. Additional inlets should be placed at the points where the design peak flow on the street is approaching the allowable street hydraulic conveyance capacity (SHCC). There are four major types of inlets used for street drainage. They are grate inlet, curb-opening inlet, combination inlet, and slotted inlet. There are two major hydraulic factors to determine the inlet performance. They are water depth at the inlet and local street slope at the inlet. When an inlet is placed on a continuous grade, the stormwater spreads out from the curb toward the street crown. The performance of an inlet is subject to debris clogging. The performance of a curb-opening inlet is similar to a side weir. The flow interception capacity of a curb-opening inlet is empirically developed using English units.
