2026 02 12 Crestmont CC and Eagle Rock Ave Stormwater Management Report

Table 6 – Future Precipitation Summary for 24-Hour Storm Events 2-yr 10-yr 25-yr 100-yr (in) (in) (in) (in) 4.08 6.37 8.13 11.60 A time of concentration was calculated for each watershed. The time of concentration is defined as the time for runoff to travel from the hydraulically most remote point of the watershed to the point of interest. Values of the time of concentration were determined for existing and proposed conditions based on land cover and slope of the flow path using methods described in TR-55 and Chapter 5 of the New Jersey Best Management Practices (BMP) Manual. A time of concentration calculation was performed for both the pervious and impervious land coverage areas within each watershed in order to more accurately model peak runoff rates. For the post- construction time of concentration calculations, the McCuen-Spiess limitation is applied to the sheet flow travel time portion of the calculation. Due to technical limitations of the hydrologic software used to develop hydrographs, the minimum time of concentration is 2 minutes. A runoff curve number (CN) was selected based upon the land cover type and underlying soil hydrologic classification within each watershed. In accordance with Chapter 5 of the New Jersey BMP Manual, peak runoff rates are calculated for each individual land cover type within the watershed and then hydraulically added together to determine the peak runoff rate of the watershed, rather than using the weighted runoff curve number (CN) methodology. Runoff curve numbers are referenced from Tables 2-2a and 2-2c of TR-55: Urban Hydrology for Small Watersheds. 3.1.3 Points of Analysis All stormwater runoff generated from the area of redevelopment ultimately discharges to the existing conveyance networks located within the Eagle Rock Avenue right-of-way, but leaves the subject tract via the points of analysis described below: Point of Analysis 1 (POA-1) refers to an existing manhole within Eagle Rock Avenue, to the northwest of the subject property. Runoff from this point is ultimately conveyed to xx via the existing conveyance network. Point of Analysis 2 (POA-2) refers to an existing catch basin within Eagle Rock Avenue, to the northeast of the subject

om this point is ultimately conveyed to xx via the existing conveyance network. Point of Analysis 2 (POA-2) refers to an existing catch basin within Eagle Rock Avenue, to the northeast of the subject property. Runoff from this point is ultimately conveyed to xx via the existing conveyance network. 7