Drainage Report

NY . as ENGINEERED SOLUTIONS filte (fa West Essex Highlands Filterra HC Sizing West Orange, NJ 10/19/2023 Sizing Basis: Filterra High Capacity biofiltration system has received final certification from the NIDEP for 80% TSS removal. Per the NJDEP, Filterra HC is considered a Green Infrastructure (Gl) MTD. The sizing for the Filterra HC system under NDEP regulations is based on the methodology outlined in Chapter 5 of the NIDEP BMP Manual. The NRCS method is utilized to determine a water quality flow rate for the drainage area in question. To validate the sizing, the parameters below were assumed. Design Parameters: Design Storm = NJDEP Water Quality Design Storm (1.25-inch/2-hour storm event) Filterra HC Media Flow Rate = 300 inches/hour Time of Concentration = 10 minutes Allowable Ponding in Filterra = OF Design Summary: Utilizing NRCS Method and HydroCAD software, a hydrograph can be derived to represent the design storm. As seen in the provided HydroCAD report, the WO flow is routed to an appropriately sized Filterra unit. Since the Filterra system can provide up to 9” of ponding, some flow attenuation is possible, The Filterra system is able to accommodate a portion of the water quality volume in the head space above the media and release it at the system's NJDEP certified maximum treatment flow rate. CB-1 3061 1122 10 0.18 Ax6 / 6x4 CB-2 4262 16059 10 0.27 4.5x7.83 / 7.83x4.5 CB-3 2710 996 10 0.16 4x6 / 6x4 CB-4 9984 14522 10 0.61 6x12 / 12x6 CB-5 1979 736 10 0.12 4x4 CB-6 1877 3847 10 0.12 4x4 CB-7 3034 1131 10 0.18 4x6 / 6x4 CB-8 10407 7883 10 0.63 6x12 / 12x6 CB-9 3137 3241 10 0.19 4x6 / 6x4 Hi, CB-10 9901 6075 10 0.59 6x12 / 12x6 £ CB-11 21581 6562 10 1.28 18x8 g CB-12 3189 6920 10 0.2 4x6 / 6x4 CB-13 1200 3300 10 0.08 Ax4 CB-14 9356 2246 10 0.56 6x12 / 12x6 CB-45 9342 6767 10 0.56 6x12 / 12x6 CB-46 21640 3216 10 1.28 18x8 CB-47 820 2302 10 0.05 4x4 CB-48 7588 3216 10 0.45 6x10 / 10x6 CB-49 5637 1150 10 0.33 6x8 / 8x6 CB-50 2151 1463 10 0.13 4x4 CB-58 3789 2752 10 0.23 4.5x7.83 / 7.83x4.5 Thank you for the opportunity to present this to you and your client. Please do not hesitate to contact me should you have any additional questions. Sincerely, Dixon J. Wiley Storm Water Design Engineer Contech Engineered Solutions, LLC.