A system for separating waste materials from a flowing stream of surface water, said system comprising a vertical cylindrical vessel and a vertical cylindrical structure (332, 333) located within and spaced from an inner wall of the cylindrical vessel, said system sized to accommodate a projected normal fluid flow and configured so that the flowing stream containing waste material entering the vessel a. flows into a peripheral space between the inner wall of the cylindrical vessel and the cylindrical structure (332, 333) located therein, b. the flowing stream passes through a perforated wall portion of the cylindrical structure (332, 333), and c. exits through an effluent pipe located at a lower portion of a central space enclosed within the cylindrical structure (332 333), the system further comprising an overflow structure (235, 240, 222, 224) mounted within the cylindrical vessel and on a top portion of the cylindrical structure (332, 333), said over flow structure comprising a combination of one or more upwardly extending filtering structures (235, 240) and one or more weirs (222, 224) sized to receive flow in excess of the projected normal fluid flow and filter at least a portion of the waste material from said excess flow and to direct such excess flow to the effluent pipe wherein: a. at a first increased flow rate in excess of the projected normal fluid flow, said increased amount of flow passes through a first overflow filtering structure, b. at a second increased flow rate in excess of the first increased flow rate, said second increased amount of flow passes through a second overflow filtering structure, c. at a third increased flow rate in excess of the second increased flow rate, said third increased amount of flow passes over a weir, such that all of the flow of fluid in excess of the projected normal fluid flow entering the system passing through the overflow structure (235, 240, 222,224) and exiting said system through the effluent channel, characterized in, that d. at a fourth increased flow rate in excess of the third increased flow rate, said fourth increased amount of flow passes over a second weir, wherein the second weir comprises a cylindrical barrier extending above and below the top of the first weir, the second weir having a diameter (d 3) greater than the diameter (d 2) of the first weir such that there are flow channels (230,220) both external and internal of the second weir, said internal flow channel being exterior of the first weir. a. flows into a peripheral space between the inner wall of the cylindrical vessel and the cylindrical structure (332, 333) located therein, b. the flowing stream passes through a perforated wall portion of the cylindrical structure (332, 333), and c. exits through an effluent pipe located at a lower portion of a central space enclosed within the cylindrical structure (332 333), a. at a first increased flow rate in excess of the projected normal fluid flow, said increased amount of flow passes through a first overflow filtering structure, b. at a second increased flow rate in excess of the first increased flow rate, said second increased amount of flow passes through a second overflow filtering structure, c. at a third increased flow rate in excess of the second increased flow rate, said third increased amount of flow passes over a weir, d. at a fourth increased flow rate in excess of the third increased flow rate, said fourth increased amount of flow passes over a second weir, wherein the second weir comprises a cylindrical barrier extending above and below the top of the first weir, the second weir having a diameter (d 3) greater than the diameter (d 2) of the first weir such that there are flow channels (230,220) both external and internal of the second weir, said internal flow channel being exterior of the first weir.