O30 Princeton Hydro Report Dated 9 3 25

West Essex Highlands Review West Orange, NJ Permit No. 722-04-0001.1 LUP230001 April 2025 applicant's Figure 9: Existing Conditions Drainage Path for POA-2, demonstrating how the aie stops approximately 700 feet short of the POA location. model states 14.76 cfs (page 22) while their report states 17.53 cfs (page 14). Princeton Hydro also found that the existing peak flow rates in the report do not match the flow rates in the model results found in the report appendix. This should be corrected. For the purpose of this report, the he results found in the modeling calculation appendix were evaluated against Princeton Hydro's own calculations. Based on our calculations the peak flow rate for the development is 3.76 cfs under existing conditions for the two-year storm. Currently the design's peak flow rate under the post-development conditions is 7.24 cfs which is almost twice what should be permitted. Princeton Hydro calculated the peak flow rate for the 100-year storm at 37.7cfs but the applicant's model states the peak flow rate at 72.79. The peak flow rate for the proposed condition is 38.99 cfs. During the 100-year storm, the proposed Site will actually generate higher peak flow rate than what currently exists. This is an alarming situation especially considering there are flood prone areas immediately downstream. To meet the peak flow rate requirements state forth by the NJDEP and the local ordinance would require the volume storage for the BMPs to be dramatically increased. This would have a substantial impact on the current site design. Princeton Hydro, LLC Page | 20