2024 03 Drainage Statement

I. Drainage Summary This Drainage Statement has been prepared to define and analyze the stormwater drainage conditions that would occur as a result of the development of Block 80.03, Lot 10 as shown on the Township of West Orange Tax Map Sheet No. 32, located in the Township of West Orange, Essex County, New Jersey. The subject site consists of 5.77 acres (251,368 SF) and is located at 10 Ridge Road. Under existing conditions, the site is undeveloped, consisting of overgrown wooded areas. The proposed project consists of the construction of a 2,900 SF footprint, two and a half story single-family residential dwelling. Additional site improvements will include a paved driveway, swimming pool, pickleball court, landscaping, grading, stormwater management, utilities and other associated site amenities as shown on the accompanying Site Plan drawings. The project also proposes a sanitary sewer main extension. The new development will result in 39,823 SF (0.91 AC) of disturbance on site and 2,418 SF (0.06 AC) disturbance within the right-of-way for a total disturbance of 42,241 SF (0.97 AC), along with a 10,113 SF (0.23 AC) increase in impervious coverage. Of the increase in impervious coverage, 3,916 SF (0.09 AC) is motor vehicle surface consisting of the proposed driveway. The project consists of less than one (1) acre of disturbance and will not increase the net impervious coverage on-site by ¼ acre or more, nor the motor vehicle surface. Therefore, the proposed project does not meet the definition of a ‘major development’ as defined by NJAC 7:8 and therefore is not subject to the NJDEP Stormwater Management Rules & Regulations (NJAC 7:8). As the proposed development proposes disturbance of greater than 5,000 SF with an increase of impervious area less than ¼ acre, the project is subject to New Jersey standards for Soil Erosion & Sediment Control runoff rate reductions for downstream stability required for the 2 & 10-year storms. The stormwater drainage for the proposed site has been designed to maintain existing runoff patterns to the maximum extent feasible. In existing conditions, stormwater runoff from the project area drains to two points of analysis. Stormwater runoff from the northern corner of the site flows via overland flow to the existing headwall located within the adjacent Lot 21. The remaining stormwater runoff within the project area flows via

water runoff from the northern corner of the site flows via overland flow to the existing headwall located within the adjacent Lot 21. The remaining stormwater runoff within the project area flows via overland to the existing concrete channel at the eastern corner of the site. Aaron Friedman DEC# 5142-24-00053 March 2024 1