Patent ID: 7980273

Claim:
The method of restricting drainage flow from a catch basin; the method comprising the steps of: placing a removable or modifiable first flow restrictor plate with one or more flow openings of a predetermined open area (Oa) in an outlet or orifice of a catch basin wall or drain pipe or in-line of a drain pipe to slow down the rate of drainage to attempt to achieve a prescribed or preferred draw down time; measuring the time required to draw down the catch basin after a first flush rain event; increasing or decreasing the time to draw down by either removing the flow restrictor plate and replacing with a second flow restrictor plate having more or less flow opening area or modifying said first flow restrictor plate by plugging some of the flow area or increasing said flow area by adding to or enlarging the one or more flow openings; more area (Oa+) increasing flow volume, less area (Oa−) decreasing flow volume to achieve the prescribed or preferred draw down time.