CME Associates Review 2

Ne ASSOCIATES Chairman and Members of the West Orange Township Planning Board July 29, 2024 Re: West Essex Highlands, LLC (PB 24-01) Our File No. VWRP0179.01 Preliminary & Final Site Plan - Review #2 Page 10 21. The 10-year and 100-year water surface elevations on outlet structure #2 and infiltration basin #2 details are inconsistent with the hydrographs. This discrepancy must be resolved. 22. The top of grate elevation for outlet structure #2 is inconsistent between Sheet SP-21, SP- 25 and the hydrographs. This discrepancy must be resolved. 23. Per Chapter 9.8 of the NJ BMP Manual, small-scale infiltration basins require a minimum of 2.0 ft of separation between the lowest elevation of the sand layer and the seasonal high-water table, whereas small-scale basin #2 provides a separation of 1.5 ft between the lowest elevation of the sand layer and the seasonal-high water table. Design modifications appear to be required. 24. Sheet SP-20 must be revised to identify the pipes proposed in conjunction with porous pavement system #3. 25. Sheet SP-20 indicates that outlet structure #3 has a 6” orifice at elevation 559.5, however, the hydrograph routings and outlet structure #3 detail on Sheet SP-25 indicate that a 4’ weir is proposed at elevation 559.22. This discrepancy must be resolved. 26. The hydrograph routings for porous pavement system #3 utilize an exfiltration rate of 10 inches per hour while the Stormwater Management Report indicates a permeability rate of 4 inches per hour and the porous pavement #3 section on Sheet SP-25 indicates a permeability rate of 8 inches per hour. This discrepancy must be resolved. 27. Verify the sizes of the pipes connected to outlet structure #3 as they are inconsistent between the plans and details. Sheet SP-20 and the details on sheet SP-25 must be revised accordingly. 28. Sheet SP-20 indicates that outlet structure #4 has a 6” orifice at elevation 573.5, however, the hydrograph routings and the outlet structure #4 detail on Sheet SP-25 indicate that outlet structure #4 has a 6” orifice at elevation 572.5 and a 4’ weir at elevation 574.0. This discrepancy must be resolved. 29. Sheet SP-19 indicates that outlet structure #5 has a 6” orifice at elevation 579.5, however, the hydrograph routings and the outlet structure #5 detail on Sheet SP-25 indicate that outlet structure #5 has a 4’ weir at elevation 579.25. This

ure #5 has a 6” orifice at elevation 579.5, however, the hydrograph routings and the outlet structure #5 detail on Sheet SP-25 indicate that outlet structure #5 has a 4’ weir at elevation 579.25. This discrepancy must be resolved. 30. Verify the size of pipes connected to outlet structure #6 as they are inconsistent between the plans and details. Sheet SP-19 and the details on Sheet SP-25 must be revised accordingly. 31. Sheet SP-19 indicates that outlet structure #6 has a 6” orifice at elevation 600.5, however, the hydrograph routings and the outlet structure #6 detail on Sheet SP-25 indicate that outlet structure #6 has a 6’ weir at elevation 600.02. This discrepancy must be resolved. S:\West Orange\Planning Board\VWRP0179.01 - West Essex Highlands, Inc\Review #2 07-29-24 docx