2025 08 15 WEH SWM CME Memo

Chairman and Members of the West Orange Township Planning Board August 15, 2025 Re: West Essex Highlands, LLC (PB 24-01) Our File No. 115.WRP0179.V01 Response To Objector’s Stormwater Management System Review Page 5 have been designed to provide the required separation between the bottom of the BMP and the SHWT. Further, the Applicant will be required to complete additional soil testing during construction and post construction for all infiltration BMPs in accordance with the NJ BMP Manual to verify consistency with the proposed stormwater management design as well as compliance with the applicable stormwater management regulations. 2.3 Soil Testing Requirements for BMPs: “…Princeton Hydro compared the number of test pits for each BMP to the number required by the NJDEP Manual to confirm the applicant performed the minimum number of soil tests. Princeton Hydro compared the infiltration area of each BMP on the plan to what was entered into the model. Table 1 is a comparison of the infiltration area found in the model calculations and the infiltration area shown on the plan. The infiltration area is the bottom of the basin, not the side slopes. Table 1: Comparison of Infiltration Areas Shown in the Plan and Model BMP ID – BMP Type Infiltration Area, Model (SF) Infiltration Area, Plan (SF) 1 – Large Scale Infiltration Basin 2 – Small Scale Infiltration Basin 3 – Porous Pavement 4 – Porous Pavement 5 – Porous Pavement 6 – Porous Pavement 7 – Small Scale Infiltration Basin 8 – Porous Pavement 9 – Porous Pavement 10 – Small Scale Infiltration Basin 11 – Porous Pavement 12 – Small Scale Infiltration Basin 42,000 26,023 5,227 12,197 14,810 35,719 14,375 10,019 6,534 9,583 13,504 900 45,490 25,830 5,558 12,369 14,611 37,473 13,405 15,900 17,981 9,467 22,826 1,004 Difference, Model – Plan (SF) -3,490 193 -331 -172 199 -1,754 970 -5,881 -11,447 116 -9,322 -104 As demonstrated, there are differences between what was modeled and what was shown on the plan. A majority of these differences are not consequential, but the differences at BMP 1, 8, 9 and 11 are much more significant as the infiltration areas as modeled are much larger than the final BMP footprints as proposed on the plans. The modeling must be revised accurately analyze the proposed conditions.” S:\West Orange\Planning Board\VWRP0179.01 - West Essex Highlands, Inc\2025-08-15 - WEH - SWM Memo.docx