Abstract: A storm water receptor having at least one inlet and an outlet positioned at a discharge level lower than the level of the intake provided with a novel, removable divider which divides the receptor into an upper chamber and a lower chamber, having a float-actuated trap door that permits water entering the upper chamber of the catch basin or field inlet to be diverted and flow into the lower chamber until the lower chamber is filled with liquid, at which point the entrance into the lower chamber closes, and water entering the upper chamber passes directly out of the upper chamber through the discharge pipe. In an alternative embodiment of the invention, the float-activated trap door can be replaced with a stationary, removable plate or ramp.