Stormwater Management Report Feb 2026 resubmissionrcd 2 26 2026

The hydrology for the site was calculated using the NRCS Runoff Equation and Dimensionless Unit Hydrograph as noted in Part 630, Hydrology National Engineering Handbook. The following particular references were used: • Curve Numbers were established via Chapter 9 – Hydrologic Soil-Cover Complexes • Time of Concentrations were calculated in accordance with Chapter 15 • Rainfall Distributions are based on NOAA Type D rainfall distribution • The Standard Unit Hydrograph was utilized • The rainfall depths are based on Essex County NOAA Atlas 14 Data and adjusted per NJAC 7:8-5.7 Tables 5-5 and 5-6 as noted below: Return Period Current Adjusted Projected Adjusted Rainfall Depth Rainfall Depth (inches) (inches) 2 Year Storm 3.47 4.09 10 Year Storm 5.38 6.37 100 Year Storm 9.18 11.52 Based upon the Essex County Soil Survey, the soil types native to the site include: Soil Type Soil Type Name Hydrologic Soil Group USBONB Urban Land, Boonton Substratum Unrated* *When the hydrologic soil group (HSG) is unrated for a particular soil, the stormwater design shall assume HSG B for existing conditions and HSG D for proposed conditions for projects located outside the Coastal Plain. Based on the methodology and data noted above a hydrologic evaluation of the NJDEP Water Quality, 2, 10, and 100-year storm events was prepared. This report will address compliance with the following standards: • West Orange Township Stormwater Control Standards (§ 25-29) 3. Existing Drainage Conditions The area to be analyzed consists of approximately 0.637 acres and is comprised of the existing building, parking lot, and associated grassed areas within the limit of disturbance. In the existing condition, stormwater runoff is conveyed overland to five (5) separate inlets. The two yard inlets and two inlets within and surrounding the existing parking lot captures majority of the

the existing condition, stormwater runoff is conveyed overland to five (5) separate inlets. The two yard inlets and two inlets within and surrounding the existing parking lot captures majority of the on-site runoff, ultimately discharging offsite through the existing 15” RCP stormwater line. The round inlet within the existing entrance on Blueberry Bend captures runoff from the adjacent properties, also ultimately discharging to the northeast offsite. The subject site has been Mavis Tire Supply, LLC July 2025 DEC# 1956-24-04187 2 Last revised February 2026