Drainage Statement 07 2025 submission

I. Introduction This Drainage Statement has been prepared to analyze the stormwater drainage conditions that would occur as a result of the redevelopment of Block 105, Lot 64.01, located in the Township of West Orange, Essex County, New Jersey. The analysis contained within this Drainage Statement is limited to the proposed area of disturbance. According to the Township of West Orange Zoning Map, the site is located in the (B-2) General Business District. The proposed property consists of 0.74 acres (+/-32,118 SF) and is located on Prospect Avenue (New Jersey State Highway #280), West Orange Township. The site is currently developed with an existing realtor’s office consisting of a two (2) story building, parking, sidewalks, lighting and other site amenities. The proposed project will replace the existing 3,338 SF (GFA) building east of Prospect Avenue to be redeveloped with an Automative Service and Retail Center. The proposed building will include a total footprint of approximately 6,952 SF (0.16 acres). The overall development will result in 0.04 acres (1,329 SF) of new impervious surfaces (inclusive of MVS)(less than 0.25 acres of impervious coverage increase), and 0.66 acres of land disturbance (less than 1 acre of disturbance). Moreover, the proposed development will reduce existing motor vehicle surfaces by approximately 670 SF. Additional site improvements include modifications to the associated parking areas, landscaping, lighting, signage, and utilities as reflected on the accompanying Site Plan drawings. II. Existing Pipe Capacity The subject site has been evaluated using the Manning’s Equation to understand the maximum flow capacity for each of the pipes proposed in the stormwater system. (1.49) 2/3 𝑄𝑄 = 𝐴𝐴𝐴𝐴 √𝑆𝑆 𝑛𝑛 Equation 1: Manning’s Equation This was determined by first approximating the maximum flow conveyed into the existing system from the 6” CIP line. The slope of the 6” CIP pipe, connecting from the adjacent property, cannot be verified from the property survey, however it can be assumed that capacity of the pipe cannot exceed the downstream pipe at 2.5% slope. The flow from this pipe (1.0 CFS utilized in calculations) has been

ified from the property survey, however it can be assumed that capacity of the pipe cannot exceed the downstream pipe at 2.5% slope. The flow from this pipe (1.0 CFS utilized in calculations) has been modeled in the attached Pipe Sizing calculations to demonstrate the proposed system has adequate capacity to convey the flow from the adjacent property, even when flowing at full capacity. III. Drainage Summary As a result of the proposed redevelopment, the overall impervious coverage onsite will increase from existing to proposed conditions by 4.7% (approximately 1,329 SF) and the limit of disturbance for proposed site improvements is approximately 0.66 acres. Mavis Tire Supply, LLC 1 July 2025 DEC# 1956-24-04187