Stormwater Management Report Feb 2026 resubmissionrcd 2 26 2026

Bioretention Basin Summary Table Storm Event (years) Water Surface Elevation (ft) Outflow (CFS) Water Quality 622.86 0.00 Current – 2 623.15 0.27 Current – 10 623.29 0.48 Current – 100 623.54 0.85 Projected – 2 623.20 0.35 Projected – 10 623.36 0.58 Projected – 100 623.69 1.07 Underground Detention Basin Summary Table Storm Event (years) Water Surface Elevation (ft) Outflow (CFS) Water Quality 618.77 0.22 Current – 2 618.91 0.24 Current – 10 619.58 0.31 Current – 100 620.83 0.95 Projected – 2 619.13 0.26 Projected – 10 619.95 0.34 Projected – 100 621.44 1.36 6. Green Infrastructure Compliance The basins noted above have been designed to comply with the stormwater runoff quantity, quality, and groundwater recharge requirements for the proposed development as applicable. The proposed basin has been designed in accordance with NJAC 7:8 and the New Jersey Stormwater Best Management Practices. The tables below summarize the design considerations for each basin, see the Site Plan details for additional information. Small-Scale Bioretention Basins (Table 5-1 – Quantity, Quality, & Recharge) Design Criteria Required Provided Total Drainage Area -- 0.140 acres Min. Storage Volume below 0.008 Ac-FT 0.008 Ac-FT 1st Orifice Depth of Soil Bed 18 in. Terrestrial Forested 18 in. Terrestrial Forested Community Community Max. Contributory DA

Bed 18 in. Terrestrial Forested 18 in. Terrestrial Forested Community Community Max. Contributory DA 2.5 acres 0.140 acres Max. Drain Time 72 hours N/A Underdrains are proposed Separation from SHWT 1 foot (Underdrain) SHWT Not encountered to depth elevation 615.0 (TP-05) Design Permeability Rate Min. = 0.5 in/hr <0.5 in/hr Max. = 10 in/hr Underdrains are proposed Max. Depth of WQ Storm 1.0 feet 0.86 feet Mavis Tire Supply, LLC July 2025 DEC# 1956-24-04187 5 Last revised February 2026

7. Water Quantity Control Compliance The site has been designed to reduce peak flows for the 2-, 10- and 100-year storm events as compared to the pre-development conditions. The point of analysis has been identified on the Drainage Area Maps as previously described. Below is a summary table demonstrating compliance with the flow reduction requirements. Point of Analysis #1 Storm Event Existing Peak Proposed Peak Percent Flow Rate (cfs) Flow Rate (cfs) Reduction Current 2-year 1.55 1.52 1.9% Current 10-year 2.65 2.49 6.0% Current 100-year 5.01 4.89 2.4% Projected 2-year 1.90 1.85 2.6% Projected 10-year 3.26 3.00 8.0% Projected 100- 6.55 6.40 2.3% year 8. Water Quality Compliance In accordance with the West Orange Stormwater Control Ordinance, section 25-29.4.r.2(a), major developments are required to provide 80% TSS removal for the stormwater runoff from the net increase in motor vehicle surface. The project proposed a net decrease of motor vehicle surface of 0.009 acres (0.276 acres in the existing condition and 0.267 acres in the proposed condition) therefore water quality is not required, however, the proposed bioretention basin has been designed to treat 0.064 acres of motor vehicle surface in the proposed condition to 80% TSS removal. For reference, the project proposes a net increase in overall impervious area of 0.04 acres. 9. Groundwater Recharge Compliance As determined by NJ GeoWeb Mapping, this project area falls within the Metropolitan Planning Area (PA1). Under existing conditions, the site is not covered in woody vegetation nor regrowth. In accordance with New Jersey Standard for Land Grading (revised 2017), non woody vegetated PA1 areas fall under the soil compaction exemption list as a "urban redevelopment" and is defined by NJDEP as "previously developed". Therefore, this project will not be subject to comply with ground water recharge requirements set forth in NJAC 7:8-5.4. 10. Storm Sewer Design The proposed stormwater management

viously developed". Therefore, this project will not be subject to comply with ground water recharge requirements set forth in NJAC 7:8-5.4. 10. Storm Sewer Design The proposed stormwater management collection system has been designed to have hydraulic capacity for the 25-year storm event. The Rational Method was used to determine inflow rates to each structure and Manning’s Equation was used to establish pipe capacity. In accordance with the NJDEP BMP Manual Chapter 5, weighted runoff coefficients were computed for each drainage area based on land cover and hydrologic soil group. A minimum time of concentration Mavis Tire Supply, LLC July 2025 DEC# 1956-24-04187 6 Last revised February 2026

of six minutes was assumed for each area. Supporting calculations and the Inlet Drainage Area Map can be found in the appendix. 11. Soil Erosion and Sediment Control Compliance The project has been designed to comply with the Standards for Soil Erosion and Sediment Control in New Jersey. Soil erosion control measures such as a stabilized construction entrance, inlet protection and silt fence are shown on the plans. In addition, the proposed basins and underground stormwater conveyance system discharge to existing stormwater infrastructure located on the site, therefore providing a stable point of discharge. 12. Conclusion The proposed development has been designed with provisions for the safe and efficient control of stormwater runoff in a manner that will not adversely impact the existing drainage patterns, adjacent roadways, or adjacent parcels. In addition, the proposed development satisfies the runoff quality and groundwater recharge requirements set forth by the Township of West Orange Land Use Ordinance and reduces the peak flow rates to the point of analysis to the maximum extent practical and in line with the intent of the regulations through the use of the proposed green infrastructure and underground detention. With this stated, it is evident that the proposed development will not have a negative impact on the existing drainage conditions, water quality or groundwater recharge on-site or within the vicinity of the subject site. Mavis Tire Supply, LLC July 2025 DEC# 1956-24-04187 7 Last revised February 2026

APPENDIX

NRCS WEB SOIL SURVEY

United States Department of A product of the National Cooperative Soil Survey, Custom Soil Resource Agriculture a joint effort of the United Report for States Department of Natural Agriculture and other Federal agencies, State agencies including the Essex County, Resources Conservation Service Agricultural Experiment Stations, and local participants New Jersey June 27, 2025

Preface Soil surveys contain information that affects land use planning in survey areas. They highlight soil limitations that affect various land uses and provide information about the properties of the soils in the survey areas. Soil surveys are designed for many different users, including farmers, ranchers, foresters, agronomists, urban planners, community officials, engineers, developers, builders, and home buyers. Also, conservationists, teachers, students, and specialists in recreation, waste disposal, and pollution control can use the surveys to help them understand, protect, or enhance the environment. Various land use regulations of Federal, State, and local governments may impose special restrictions on land use or land treatment. Soil surveys identify soil properties that are used in making various land use or land treatment decisions. The information is intended to help the land users identify and reduce the effects of soil limitations on various land uses. The landowner or user is responsible for identifying and complying with existing laws and regulations. Although soil survey information can be used for general farm, local, and wider area planning, onsite investigation is needed to supplement this information in some cases. Examples include soil quality assessments (http://www.nrcs.usda.gov/wps/ portal/nrcs/main/soils/health/) and certain conservation and engineering applications. For more detailed information, contact your local USDA Service Center (https://offices.sc.egov.usda.gov/locator/app?agency=nrcs) or your NRCS State Soil Scientist (http://www.nrcs.usda.gov/wps/portal/nrcs/detail/soils/contactus/? cid=nrcs142p2_053951). Great differences in soil properties can occur within short distances. Some soils are seasonally wet or subject to flooding. Some are too unstable to be used as a foundation for buildings or roads. Clayey or wet soils are poorly suited to use as septic tank absorption fields. A high water table makes a soil poorly suited to basements or underground installations. The National Cooperative Soil Survey is a joint effort of the United States Department of Agriculture and other Federal agencies, State agencies including the Agricultural Experiment Stations, and local agencies. The Natural Resources Conservation Service (NRCS) has leadership for the Federal part of the National Cooperative Soil Survey. Information about soils

cultural Experiment Stations, and local agencies. The Natural Resources Conservation Service (NRCS) has leadership for the Federal part of the National Cooperative Soil Survey. Information about soils is updated periodically. Updated information is available through the NRCS Web Soil Survey, the site for official soil survey information. The U.S. Department of Agriculture (USDA) prohibits discrimination in all its programs and activities on the basis of race, color, national origin, age, disability, and where applicable, sex, marital status, familial status, parental status, religion, sexual orientation, genetic information, political beliefs, reprisal, or because all or a part of an individual's income is derived from any public assistance program. (Not all prohibited bases apply to all programs.) Persons with disabilities who require 2