05 Stormwater Statementrcd 10 14 24

Stormwater Management Statement Proposed Site Improvements Township of West Orange, New Jersey October 8, 2024 PRE-DEVELOPMENT DRAINAGE CONDITIONS The existing condition of the site consists of one (1) drainage area (E-1) including the entirety of the developed lot. The site drains via overland flow to Franklin Avenue, and the southern and eastern neighboring properties, from where it is conveyed into the local stormwater system located within Chestnut Street. The following table summarizes the qualities of Drainage Area E-1 utilized in the stormwater analysis: TABLE 1: PRE-DEVELOPMENT DRAINAGE AREAS Drainage Area Description Area Extents Impervious Area Time of Concentration E-1 Pre-Development Drainage to Chestnut street 10,000 SF 8,524 SF 6 Minutes PROPOSED DRAINAGE CONDITIONS Under proposed conditions, the site is comprised of one (1) drainages area referred to as (P-1). The roof drainage of the existing building is currently conveyed to a drainage pipe, along with surface runoff captured at the southwest Corner of the property via one trench drain connected to one storm inlet on site via 6” PVC pipe, and daylights into the Franklin Avenue via one 8” PVC pipe. A portion of the site also drains to the adjacent neighboring properties. Eventually all of the stormwater on site is directed to the existing conveyance system located in Chestnut Street. TABLE 2: POST-DEVELOPMENT DRAINAGE AREAS Drainage Area Description Area Extents Impervious Area Time of Concentration P-1 Post-Development Drainage to Chestnut Street 10,000 SF 8,348 SF 6 Minutes STORMWATER MANAGEMENT ANALYSIS The project aims to disturb less than one acre of land and has reduced impervious surfaces by 176 SF and has increased motor vehicle surface by less than a 0.25 AC and therefore is not considered a Major Development as indicated by the Municipal Ordinance and New Jersey Department of Environmental Protection (NJDEP). The subject property is located within an urban redevelopment area (metropolitan planning area (PA-1)) and is therefore exempt from compaction remediation. The project is designed to conform to the stormwater management requirements set forth by the Township of West Orange, Hudson Essex Passaic County Soil Conservation District, and the NJDEP. A hydrograph comparison has been performed to evaluate the pre- and post-construction runoff. Due to a reduction in impervious cover

son Essex Passaic County Soil Conservation District, and the NJDEP. A hydrograph comparison has been performed to evaluate the pre- and post-construction runoff. Due to a reduction in impervious cover relative to the existing condition, the included hydrologic analysis demonstrates that for stormwater leaving the site, post-construction runoff hydrographs for the 2, 10 and 100-year storm events do not exceed, at any point in time, the pre-construction runoff hydrographs for the same events.