complete drainage report rev 9

time of concentration = 10 minutes i = 3.2 in/hr (page 5-8, Fig. 5-3 of the NJ Stormwater BMP Manual) c = 0.99 (runoff coefficient for impervious) Q = ciA = 0.99 x 3.2 x 0.25 = 0.79 cfs Given the site runoff is 0.79 cfs and based on Table A-1 below, the Cascade Separator™ Model CS-3 with an MTFR of 1.02 cfs would be the smallest model approved that could be used for this site to remove 50% of the TSS from the impervious area without exceeding the MTFR. The sizing table corresponding to the available system models is noted below. Additional specifications regarding each model can be found in the Verification Appendix under Table A-1. Table A-1 Cascade Separator™ Models and Associated MTFRs Model CS-3 CS-4 CS-5 CS-6 CS-8 CS-10 CS-12 Manhole Diameter (ft) 3 4 5 6 8 10 12 MTFR (cfs) 1.02 1.80 2.81 4.05 7.20 11.3 16.2 50% Maximum Sediment Storage Area Volume (ft3) 5.3 9.4 14.7 21.2 37.7 58.9 84.8 A detailed maintenance plan is mandatory for any project with a stormwater BMP subject to the Stormwater Management rules under N.J.A.C. 7:8. The plan must include all of the items identified in the Maintenance requirements section of the Stormwater Management rules under N.J.A.C. 7:85.8. Such items include, but are not limited to, the list of inspection and maintenance equipment and tools, specific corrective and preventative maintenance tasks, indication of problems in the system, and training of maintenance personnel. Additional information can be found in Chapter 8: Maintenance and Retrofit of Stormwater Management Measures. If you have any questions regarding the above information, please contact Brian Salvo of my office at (609) 633-7021. Sincerely, Gabriel Mahon, Chief Bureau of Nonpoint Pollution Control 3