26 04 06 Consultant Engineer Review 2 rcd 4 8 2026

Consulting & Municipal Sue Pemeeiee ENGINEERS ur File No. 115. : "ASSOCIATES A Subsidiary of Artheon, Inc. Page 5 7. It remains for the hydrograph routings to be revised to model impervious areas and pervious areas separately with separate time of concentration calculations for each. A composite CN for impervious and pervious areas is not acceptable. 8. It remains for the Applicant to revise the proposed drainage area map to indicate flow type, length of segment and slope of each segment. Further, it remains outstanding for proposed time of concentration calculations to be submitted for review. Our office notes that proposed sheet flow lengths must be calculated utilizing the McCuen Spiess limitation. 9. Groundwater mounding calculations have been provided; however, it remains for duration of infiltration period calculations (‘t’) to be submitted to verify the groundwater mounding calculations. Our office notes that when exfiltration is utilized in the hydrograph routings, the maximum discarded volume for the projected 100-year storm event should be utilized in calculating the duration of infiltration period (‘t’). 10. It remains for the plans to be revised how roof runoff will be pre-treated prior to infiltration. As outlined in the BMP manual, pre-treatment is required for all small-scale infiltration basins that utilize exfiltration within the hydrograph routings. 11. It remains for the permeable pavement detail on the Construction Details (sheet 8) to indicate the separation from the bottom of the system to the seasonal high water table elevation. The elevation of the seasonal high-water table must be indicated. Further, it remains for the permeable pavement detail to be revised to indicate that filter fabric should be installed along the sides of the system. 12. It appears that the permeable pavement system and underground infiltration basin are discharging stormwater within the water quality storm event. The design must be revised to infiltrate the entirety of the water quality storm event in accordance with the BMP manual and the Township Code to meet water quality requirements. 13. We have reviewed the Stormwater Management Measures Maintenance Plan & Field Manuals and offer the following comments: a) As required by §25-29.12.b.7(d) of the Township Code, the plan must be revised to note that an annual maintenance report must be submitted to

Plan & Field Manuals and offer the following comments: a) As required by §25-29.12.b.7(d) of the Township Code, the plan must be revised to note that an annual maintenance report must be submitted to the Township every May 18. The report must include all preventative and corrective maintenance for the structural stormwater management measures incorporated into the design and of the development. b) As required by §25-29.12.b.7(e) of the Township Code, the Applicant must post a two- year maintenance guarantee in accordance with N.J.S.A. 49:55D-53. c) As required by §25-29.12.b.5 of the Township Code, the maintenance plan and any future revisions must be recorded upon the deed of record for the property. Prior to recording, the form of the deed must be approved by the Board Attorney and our office. D. LANDSCAPING COMMENTS 1. The Applicant has addressed all remaining landscaping comments. H:lLegacy\Howell-FS1\SEC\West Orange\Zoning Board\1 15 WRZ0154 VO1 - 127 Mitchell Streel\26-04-06 Review #2 docx