A feature of the present invention is it is adaptable to any pre-existing storm catch basin system. Another feature of the present invention is that it permits empirical analysis and verification of the draw down rate. Another feature is the present invention can be adjusted or modified to increase or decrease the rate of draw down after it has been installed to insure regulatory conditions are precisely met without difficulty. Changes in future regulatory draw down rates can be easily implemented.A flow restriction device has an orifice plate, the orifice plate having a frontal surface area A and at least one opening for the passage of fluid of an area Oa, wherein Oa is less than A. The flow restriction device may also employ a screen debris plate, the screen debris plate having a plurality of spaced openings for the passage of fluid; the sum area of the openings being .SIGMA. Osp wherein .SIGMA. Osp is greater than Oa.