21 Stormwater Mgmt Report_082025

parking. Currently, the runoff generated on site outfalls to the Rahway River along the western property line via overland flow. The Existing Drainage Area Map in Appendix F illustrates the limits of the existing drainage area and how it relates to the existing site conditions. 3.1 Point of Analysis #1 The existing drainage area flows to Point of Analysis #1 located along the western property line. The Existing Drainage Area Map in Appendix F illustrates the identified point of analysis and how it relates to the existing topography on the site. 3.1.1 Existing Drainage Area #1 Existing Drainage Area #1 contains 1.36 acres of land, of which 1.34 acres are impervious surface, and includes the portion of the existing site and building on which improvements are proposed. The portion of the shopping center which will not be disturbed is excluded from this analysis. The topography of the area slopes from east to west from a maximum elevation of approximately 378 to a minimum elevation of approximately 360 with slopes ranging from approximately 1% to 66%. The runoff from Existing Drainage Area #1 flows from east to west and ultimately discharges to Point of Analysis #1. Post-Development Site Conditions The post-development condition for the site includes the repurposing of the existing florist space to a proposed retail store with parking reconfiguration, sidewalks, stormwater infrastructure, and other site improvements. The proposed site is designed in a manner that generally maintains the existing drainage patterns. The studied watershed area in the post-development condition contains the same 1.36-acre area that was studied in the pre-development condition and consists of 1 unique drainage area: Proposed Drainage Area PDA 1A, which is described in more detail below. A proposed stormwater conveyance system will collect the runoff from the proposed building and impervious areas via pervious pavement, an inlet, manholes, and stormwater piping and redirect it to the pervious pavement system and ultimately the existing inlet located along Mount Pleasant Place. The construction of the proposed improvements will disturb approximately 0.65 acres of land and will result in a reduction of approximately 0.07 acres of impervious coverage on the site in the post-development condition. The Proposed Drainage Area Map in Appendix F illustrates the limits of the proposed

ult in a reduction of approximately 0.07 acres of impervious coverage on the site in the post-development condition. The Proposed Drainage Area Map in Appendix F illustrates the limits of the proposed drainage area and how it relates to the proposed site conditions 4.1 Point of Analysis #1 The drainage area in the post development condition flows to the same Point of Analysis #1 identified in the existing condition, located along the western property line. The proposed runoff to Point of Analysis #1 meets the stormwater management criteria set forth in NJDEP Stormwater Management Regulations by having the post-construction hydrograph not exceed the pre-construction hydrograph at any point for the two-, 10-, and 100-year storm events. Refer to Section 4.3 Stormwater Quantity Controls for a summary of the preconstruction, allowable, and post-construction flows. ▪ Stormwater Management Report for Proposed Retail Store▪ 4 ▪ August 2025 ▪