CME Associates Review 1

%. ASSOCIATES Chairman and Members of the West Orange Township Planning Board June 26, 2024 Re: West Essex Highlands, LLC (PB 24-01) Our File No. VWRP0179.01 Preliminary & Final Site Plan - Review #1 Page 10 6. Based on the construction detail for the pervious pavement system, it appears that an underdrain system is proposed. In accordance with Chapter 9.6 (Pervious Paving Systems) of the BMP Manual, pervious pavement systems with an underdrain may not be used to meet the groundwater recharge requirements. The Applicant should confirm the type of pervious pavement system being proposed and revise the SWM report and associated construction detail to reflect compliance with the BMP Manual. 7. In accordance with Chapter 9.6 of the BMP Manual, the maximum contributory drainage area for a pervious paving system is three times the area of the proposed pervious pavement. It appears that contributory drainage area will exceed the maximum permitted for the proposed system. Design modifications are required. In addition, we note that the site plan depicts pervious pavement within open lawn areas; same should be revised. 8. The stormwater management design indicates that large-scale infiltration basin #1 will collect discharge from nearby Manufactured Treatment Devices (MTDs) (i.e., Filterra) during larger storm events. Pursuant to Township and State stormwater management requirements, the large-scale infiltration basin may only be used to satisfy the standards for stormwater runoff quantity, and would require a waiver/variance from NJAC 7:8-5.3 for groundwater recharge and stormwater runoff quality. Design modifications appear to be required for compliance with the applicable stormwater management regulations. 9. It appears that soil testing, including soil profile pits and/or soil borings, have been performed throughout the site. However, copies have not been provided to the Board. The Applicant should provide a copy of the soil report to our office for review to verify the proposed stormwater management system will function as designed. 10. Site specific details for the proposed small-scale infiltration basins and any other BMP should be provided detailing all specifications (i.e., embankment and spillway elevations, sand bottom layer thickness / elevations, filter fabric, etc.). Same should comply with all requirements outlined in the NJDEP BMP Manual. 11.

pecifications (i.e., embankment and spillway elevations, sand bottom layer thickness / elevations, filter fabric, etc.). Same should comply with all requirements outlined in the NJDEP BMP Manual. 11. It does not appear that a stormwater analysis using the water quality design (WQDS), which uses a rainfall intensity of 1.25 inches over 2 hours, has been included in the stormwater report. The report should be revised to include same. 12. The Stormwater Management Report should be revised to include a Low Impact Development Checklist. 13. The Stormwater Management Report should be revised to include a completed Hydrologic Modeling Database - Data Entry Short Form. 14. Storm sewer pipe size calculations should be provided for review to confirm proposed pipe sizes will be adequately sized for proposed flows. Calculations should be provided using, at a minimum, the 25-year design storm. In addition, a storm inlet drainage area map should be included in the stormwater report. §:\West Orange\Planning Board\VWRPO179.01 - West Essex Highlands, Inc\Review #1 05-26-24 docx