Abstract: A storm water management system includes a flow control device that includes a float in a storage chamber responsive to changes in water level and a valve disposed between the storage chamber and a discharge. The valve includes a relatively movable valving member connected to the float and a fixed valving member. Each valving member has a through opening that receives storm water flowing between the storage chamber and the discharge. The through-openings overlap one another whereby relative displacement of the valving members caused by float movement defines a variable-sized orifice between the storage chamber and the discharge that regulates the discharge rate of storm water from the system. The shapes of the overlapping openings enable the valve to closely follow the ideal output hydrograph and maximize the discharge rate as a function of storm intensity, thereby minimizing the required volume of the storage chamber.

Abstract: A method for delaying the maximum rate of discharge of water from a stormwater retention basin includes varying the vertical distance of an intake opening from the waterline inversely with water depth. A flow control device for carrying out the method includes an intake pipe with an intake opening that is pivotally mounted to a float body, the pivot being spaced from the intake opening.

Abstract: A flow control device includes a float that moves vertically in response to changes in water level, a valve body that moves between extended and retracted positions, and a mechanism interconnecting the float and the valve body wherein changes of position of the float in response to changes in water level changes the position of the valve body. The valve body is placed adjacent a discharge pipe to change the effective intake area of the discharge pipe with changes in water level.

Abstract: A flow control device for a storm water management system includes a storage chamber and a number of discharge openings extending through the storage chamber. Associated with each opening is a valving mechanism that opens or closes the opening in response to changes in water level in the storage chamber.