Patent ID: 7875190

Claim:
The method of cleaning runoff water which has a variable rate of flow, comprising: providing a first chamber, for receiving and holding runoff water; feeding runoff water, to be cleaned, to said first chamber, transferring water from a first elevation within said first chamber, to a storage chamber via gravity flow, transferring water from said storage chamber from an elevation below said first elevation to a height above said first elevation and back down into a filtration chamber; providing an extended detention chamber, and transferring water from said first chamber at a second elevation that is lower than said first elevation, elevating said water above said first elevation to a third elevation and then delivering the water from said second elevation to said extended detention chamber when the water in said first chamber exceeds said third elevation; filtering said water in said filtration chamber; discharging said water from said filtration chamber after said filtration; providing flow between said extended detention chamber and said filtration chamber when said water in said extended detention chamber rises above a predetermined level; providing flow between said extended detention chamber and said filtration chamber when said water in said filtration chamber is discharged through said filter down to a predetermined level; discharging water from said first chamber at an elevation higher than said first, second and third elevations when the water level in said first chamber exceeds said third elevation.