2151002Princeton Hydro West Essex Stormwater Comments to Planning Board 20250310

Stormwater Management Review for Municipal Planning Board Approval West Highlands, Inc. Block No. 179, Lot No.32, West Orange Township, Essex County, New Jersey March 2025 Princeton Hydro, LLC: 2151.002 11 Figure 6: Cross Section of BMP 3. 2.5 IMPACTS TO WETLANDS In the existing conditions, the stormwater runoff generated from the existing topography travels over the surface and reaches the upgradient wetlands, providing valuable water to the wetland ecosystem. In the proposed condition, the discharge locations for each of the drainage areas are at the bottom of the project area, as illustrated in Figure 7. The blue arrows indicate the existing flow paths and the red arrows indicate proposed. The proposed stormwater system intends to route the stormwater runoff through a pipe network to down-gradient basins where all of the surface runoff will discharge much further downstream. The wetlands uphill of the discharge locations will therefore collect less stormwater runoff due to their reduced contributory drainage areas. Princeton Hydro included two attachments that show the existing drainage areas for eastern and western wetlands. The western wetlands have a drainage area of approximately 32 acres. The proposed improvements to this area will reduce the drainage area by 9 acres, or 28% of the total existing drainage area. The eastern wetlands have a drainage area of 48.4 acres. The proposed improvements to this area will reduce the drainage area by 16 acres, or 33% of the total existing drainage area. Figure 7: Proposed Grading Plan with Blue Arrows showing the existing drainage path and the red arrows showing the proposed drainage paths and how the runoff is being diverted from the wetlands.