2025 12 12 Engineering Review 3

Chairman and Members of the West Orange Township Zoning Board December 12, 2025 Re: PSE&G Company (ZB-24-06) Our File No. 115.WRZ0155.V04 Preliminary & Final Site Plan with ‘C’ and ‘D’ Page 6 Variances and Tree Removal Permit - Review #3 H:\Legacy\Howell-FS1\SEC\West Orange\Zoning Board\115.WRZ0155.V04 - PSE&G Company\2025-12-12 - Review #3.docx C. DRAINAGE COMMENTS 1. The proposed development will result in the disturbance of more than one acre. As a result, it is classified as a Major Development which requires that the project be designed to meet the stormwater runoff quality, quantity and groundwater recharge standards using green infrastructure. 2. In our September 9, 2024 review letter, we noted several runs of storm pipe that do not have adequate capacity to accommodate the design flow. Since the most recent submission does not address this issue, our office cannot confirm if this matter has been resolved. Testimony should be provided to the Board regarding the same. 3. A detail of a cross-section of the grass swale should be added to the plans for review. 4. The basin and grass swale details should be revised to include the peak water elevation during each storm event. 5. The “West Basin” detail on sheet 792798 should be revised to show the pipe connections to be consistent with the layout shown on sheet 792790. 6. The Stormwater Management Plan Memorandum states that a grass swale will be used to address stormwater runoff quality standards. Grass swales have the ability to achieve a maximum total suspended soils (TSS) removal rate of 50%, whereas 80% TSS removal rate is required for the stormwater runoff generated by the net increase of motor vehicle surfaces. 7. The Applicant must demonstrate the proposed grass swale meets the design standards set forth in Chapter 9.3 of the NJ BMP Manual. 8. The Applicant must demonstrate that the underground detention basin(s) meet the definition of green infrastructure in order to be utilized as a BMP to address stormwater runoff quantity standards. 9. The Applicant must demonstrate the required vertical separation between the seasonal high-water table and each of the proposed stormwater management measures has been provided. 10. The Applicant must provide the routing analysis of the revised stormwater management design to verify compliance with the applicable stormwater runoff quantity standards. 11. The

as been provided. 10. The Applicant must provide the routing analysis of the revised stormwater management design to verify compliance with the applicable stormwater runoff quantity standards. 11. The drainage areas in Post-Developed Watershed Map must be revised to reflect the stormwater management design changes. 12. The Stormwater Management Measures Maintenance Plan and Field Manuals must be revised to reflect the stormwater management design changes.