Stormwater Management Report Feb 2026 resubmissionrcd 2 26 2026

STORMWATER COLLECTION SYSTEM CALCULATIONS (PIPE SIZING)

NOTES: Project: Mavis Tire Supply, LLC Computed By: AJH 1) Design method used is Rational Method, unless otherwise noted. Job #: 1956-24-04187 Checked By: RR 2) Refer to Weighted Runoff Coefficient table Location: West Orange Township Date: 2/16/2026 for calculation of incremental areas and C values Design Storm: 25 yr SUBCATCHMENT TIME OF PIPE SECTION INCREMENTAL CUMULATIVE I PEAK RUNOFF PIPING INPUT PIPING DATA AREA CONCENTRATION Tc to Tc in Q cum. Pipe Pipe Final Tc Q to Inlet Dia. Length Man. Slope FROM TO Area (Acres) "C" A x C Ac A x C (acres) Inlet Pipe (In/Hr) for Pipe Capacity Velocity (min) (CFS) (In) (Ft) "n" (ft/ft) (min) (min.) (CFS) (cfs) (fps) EXIST. ROUND INLET PROP. MH #3 0.10 0.95 0.10 0.10 6.00 0.06 6.00 7.70 0.77 0.77 12 26.0 0.013 0.0255 5.69 7.25 PROP. INLET #7 PROP. INLET #6

0.10 0.10 6.00 0.06 6.00 7.70 0.77 0.77 12 26.0 0.013 0.0255 5.69 7.25 PROP. INLET #7 PROP. INLET #6 0.08 0.88 0.07 0.07 6.00 0.32 6.00 7.70 0.54 0.54 15 64.0 0.012 0.0035 4.14 3.38 PROP. INLET #6 PROP. MH #3 0.07 0.89 0.07 0.14 6.00 0.32 6.32 7.70 0.54 1.08 15 64.0 0.012 0.0035 4.14 3.38 PROP. MH #3 PROP. OCS #2 0.00 0.00 0.00 0.24 6.00 0.33 6.64 7.59 0.00 1.82 15 67.0 0.012 0.0035 4.14 3.38 PROP. OCS #2 EXIST. A-INLET 0.14 0.74 0.10 0.34 6.00 0.07 6.97 7.59 0.76 2.58 15 15.0 0.012 0.0035 4.14 3.38 EXIST. A-INLET EXIST. MANHOLE 0.01 0.35 0.00 0.34 6.00 0.24 7.04 7.48 0.00 2.54 15 97.0 0.012 0.0143 8.37 6.82 PROP. UG BASIN OCS EXIST. MANHOLE 0.14 0.95 0.13 0.13 6.00 0.07 6.00 7.70 1.00 1.00 15 15.0 0.012 0.0035 4.14 3.38

RESULTS OF TEST PIT EXCAVATION AND INFILTRATION TESTING – PREPARED BY ECS

Geotechnical  Construction Materials  Environmental  Facilities January 29, 2025 Ms. Rachael Dickinson Pre-Construction Project Manager Mavis Tire Supply, LLC 200 Summit Lake Drive, Suite 350 Valhalla, NY 10595 ECS Project Number: 44:2100-A Reference: Addendum No. 1 - Results of Test Pit Excavation and Infiltration Testing Mavis Store #2296 460 Prospect Avenue, West Orange, New Jersey Dear Ms. Dickinson: ECS Mid-Atlantic, LLC (ECS) is pleased to present the interpreted subsurface profiles and results from the test pits excavations and infiltration testing completed at the referenced project site location. The work described herein was performed to supplement the previous subsurface exploration executed under ECS project No. 44:2100. The purpose of the explorations was:  To perform infiltration testing, the results of which will be considered in the design of the potential stormwater management (SWM) facilities.  To further evaluate the existing fill materials and to better understand the make-up and depth of these materials to further determine suitability for support of the foundations and/or if undercuts will be necessary. Our services were provided in general accordance with the scope provided to Mavis in email correspondence dated December 12, 2024 (ECS Proposal No. 44:2237-GP), which was authorized via email on December 16, 2024. PROJECT UNDERSTANDING The project site is located at 460 Prospect Avenue, West Orange, Essex County, New Jersey. In discussions with Mavis, further evaluation of the fill material within the footprint of the proposed retail auto service building was required. In addition, as understood from information provided by Mavis, a stormwater management (SWM) facility is proposed as part of the overall site development. Limited details regarding the SWM facility were available at the time of testing and the infiltration testing locations were selected in the general location of the SWM facility as approved by Mavis. 2

the SWM facility were available at the time of testing and the infiltration testing locations were selected in the general location of the SWM facility as approved by Mavis. 2 EXECUTIVE DRIVE, SUITE 11, MOORESTOWN, NJ 08057  T: (609) 832-3910  F: (484) 840-5586 ECS Florida, LLC  ECS Mid-Atlantic, LLC  ECS Midwest, LLC  ECS Pacific, Inc.  ECS Southeast, LLC  ECS Southwest, LLP ECS New York Engineering, PLLC – An Associate of ECS Group of Companies  www.ecslimited.com “ONE FIRM. ONE MISSION.”

Mavis #2296 Additional Exploration January 29, 2025 ECS Project No. 44-2100-A Page 2 The soil profiling and infiltration test program performed was based on the information obtained from our previous subsurface exploration and discussions with Mavis. SUBSURFACE EXPLORATION AND TESTING Our exploration procedures are explained in greater detail in the Attachment 2 in the insert titled Subsurface Exploration Procedure. A rubber tracked excavator was used by Sano Drilling, and the Exploration Location Diagram in Attachment 1 depicts the approximate as-completed locations of the test pit excavations. Soil profiling and field infiltration testing was performed in general accordance with Chapter 12 of the BMP Manual. The Single Ring Infiltration Test (Subsection A5 of the Chapter 12 Appendix) was used. Upon completion of the infiltration testing, the test pits were backfilled with the excavation spoils. The spoils were placed in consecutive, generally horizontal lifts of relatively uniform thickness and tamped with the excavator bucket. Excess spoils were mounded above the backfilled test pit footprint and smoothed and firmed with the excavator bucket. SUBSURFACE CHARACTERIZATION Soils encountered were visually classified during logging on the basis of texture in general accordance with the United States Department of Agriculture (USDA) Textural Classification System per the requirements of the BMP Manual. After classification, the samples were grouped in the major zones noted on the exploration logs contained in the Attachment 2. Divisions between soil strata/soil horizons on the exploration logs are approximate; in-situ, the transitions may be gradual. Additionally, index property tests were performed on select soil samples collected to confirm USDA classifications made in the field. Each laboratory test was completed in general accordance with the applicable ASTM Standard Test Method as indicated on the laboratory testing sheets included in Attachment 3. The subsurface conditions encountered were generally consistent with the published geologic mapping available from the New Jersey Geological and Water Survey via NJ-GeoWeb and the United States Department of Agriculture Natural Resources Conservation Service

stent with the published geologic mapping available from the New Jersey Geological and Water Survey via NJ-GeoWeb and the United States Department of Agriculture Natural Resources Conservation Service (USDA-NRCS) via Web Soil Survey for the general site vicinity. TEST PIT EXISTING GROUND BOTTOM OF FILL APPROXIMATE DESIGNATION SURFACE ELEVATION ELEVATION FILL DEPTH (feet) TP-01 ±619.0 ±617.0 ±2.0 TP-02 ±619.0 ±615.75 ±3.25 TP-03 ±619.0 ±616.0 ±3.0 TP-04 ±618.0 ±617.0 ±1.0 TP-05 ±616.0 ±613.0 ±3.0

Mavis #2296 Additional Exploration January 29, 2025 ECS Project No. 44-2100-A Page 3 GROUNDWATER During the test pit exploration, groundwater was not observed within the test pits. No water was observed entering the other test pits; however, each of the test pits were not left open for 24-hour to monitor the seasonal high-water determination (SHWT). No mottling was observed in any of the test pits as well. The possibility of groundwater level fluctuations should be considered in stormwater design development. Variations in perched groundwater levels and long-term water table may occur as a result of changes in precipitation, evaporation, surface water runoff, construction activities, and other factors. INFILTRATION TEST RESULTS As previously indicated, field infiltration testing was performed within two of the test pits in general accordance with the Appendix to Chapter 12 of the BMP Manual, Subsection A5, Single Ring Infiltration Test. Findings from our field infiltration testing are reported on the Single Ring Infiltrometer Test Logs contained in the attachments. Listed in the following table present the hydraulic conductivity rate of the soil layers tested as determined by the procedure outlined in Subsection A5. TESTED SOIL APPROXIMATE USDA TEXTURAL HYDRAULIC TEST PIT INFILTRATION TEST CLASSIFICATION AT CONDUCTIVITY RATE DESIGNATION TEST ID ELEVATION TEST ELEVATION (inch/hour) TP-01 TP-01A ±615.0 SANDY LOAM 0.04 TP-02 TP-02A ±615.0 SANDY LOAM 0.39 EXISTING FILL AND SHALLOW FOUNDATIONS Based on the visual observation of the fill materials encountered while test pitting the existing fill materials on the site do not appear to be suitable for support of the building foundations. The existing

n the visual observation of the fill materials encountered while test pitting the existing fill materials on the site do not appear to be suitable for support of the building foundations. The existing fills are variable in composition, containing deleterious debris such as brick, plastic, glass, and metals. Therefore, the recommendation included in the report should be followed and these materials should be removed in their entirety below foundation elements and heavily proofrolled during site grading operations in areas supporting pavements and slabs on grade. CLOSING This letter has been prepared as an addendum to our Geotechnical Engineering Report dated December 10, 2024 (under ECS Project No. 44:2100); as such, it should only be utilized in conjunction with that exploration and report. Should any of the assumptions outlined above regarding the proposed conditions be inaccurate, alternative recommendations may apply including those provided in our geotechnical report.