JMA02P003 262 270 Main Street Development Stormwater Management Report

The selection of the appropriate model of an Aqua-Ponic Stormwater Biofiltration System is based upon both the maximum inflow drainage area and the MTFR. It is necessary to calculate the required model using both methods and to use the largest model determined by the two methods. Inflow Drainage Area Evaluation: The drainage area to the Aqua-Ponic Stormwater Biofiltration System in this example is 0.25 acres. Based upon the information in Table 1 below, one Aqua-Ponic Stormwater Biofiltration System model AP-5 would be able to treat the runoff without exceeding the maximum allowable drainage area. Maximum Treatment Flow Rate (MTFR) Evaluation: The site runoff (Q) was based on the following: CN = 98 (Curve Number for impervious) Dimensionless Unit Hydrograph (DUH) = SCS Standard DUH (peak rate factor of 484) Time of concentration = 0.8 minutes Q=0.77 cfs Given the site runoff is 0.77 cfs and based on Table 1 below, one Aqua-Ponic Stormwater Biofiltration System AP-8 with an MTFR of 0.885 cfs would be required to remove 80% of the TSS from the impervious area without exceeding the MTFR. The MTFR evaluation results will be used since that method results in the highest minimum configuration determined by the two methods. The sizing table corresponding to the available system model is noted below and on the following page. Additional specifications regarding the Aqua-Ponic Stormwater Biofiltration System can be found in the Verification Appendix. Table 1: Aqua-Ponic Stormwater Biofiltration System Models and Associated MTFRs and Maximum Inflow Drainage Areas Effective Aqua- Filtration Maximum Maximum Inflow Ponic Treatment Area Treatment Drainage Model Diameter (EFTA) Flow Rate Area Designation (ft) (sf) (cfs) (acres) AP-2 2.5 4.91 0.077 0.07 AP-3 3.5 9.62 0.150 0.15 AP-4 4.5 15.90 0.248 0.24 AP-5 5.5 23.76 0.371 0.36 AP-6 6.5 33.18 0.518 0.51 AP-7 75 44.18 0.689 0.67