Water pollution trap and methods of use thereof

A filtration device and method for removing pollutants from fluid such as storm-water. The filtration device has a chamber including a series of pivotal filtration assemblies each including a weir and filter. The filters are selected and positioned for sequentially filtering larger then smaller pollutant particles from the water flowing through the device. The weirs are configured and positioned for sequentially permitting water overflow of (and thereby taking off-line) the smaller-particle size filters then the larger-particle size filters from the water flowing through the device. And the filtration assemblies are pivotally mounted to the chamber walls and configured so that, when one of the filters becomes clogged, the water pressure against it causes that filter assembly to pivot into a bypass position permitting water to flow under it.