PB 22 10 Altera 769 LLC Filed Application with Exhibits Final Site Plan Phase 2

RUNOFF CURVE NUMBER (CN) CALCULATIONS

Project: Altera Development Company, LLC Computed By: SDP Job #: 2530-99-006 Checked By: RJC Location: Township of West Orange, Essex County, NJ Date: 6/14/2022 Drainage Area Impervious Area Curve Number HSG D - Open Space Curve HSG D - Curve Number Avg. Total Area (acres) TC (Min.) (acre) (CN) Used Area (acre) Number Wooded (CN) Used Curve (CN) Used Area Number (acre) [POI-1] - EX DA-1 0.00 98 0.00 80 0.88 77 77 0.88 18.5 [POI-2] - EX DA-2 0.97 98 0.00 80 0.94 77 88 1.92 16.1 [POI-2] - EX DA-3 1.83 98 0.24 80 0.00 77 96 2.08 6.0 4.88 [POI-2] - DA-1 0.00 98 0.20 80 0.29 77 78 0.50 18.8 [POI-2] - DA-2 UNDET 0.35 98 0.03 80 0.00 77 96 0.38 6.0 [POI-2] - DA-2A DET 0.98 98 0.11 80 0.12 77 94 1.21 14.7 [POI-2] - DA-2B DET 0.27 98 0.27 80 0.17 77 86 0.71 13.3 [POI-3] - DA-3 1.82 98

98 0.27 80 0.17 77 86 0.71 13.3 [POI-3] - DA-3 1.82 98 0.26 80 0.00 77 96 2.08 6.0 4.88 BogB D* Soil Boonton Loam, 3 to 8 percent slopes Per Essex County Soil BogBc D* Soil Boonton Loam, 0 to 8 percent slopes, extremely stony Survey & Dynamic Earth Report BouB D* Soil Boonton – Urban Land, Boonton Substratum Complex, 0 to 8 percent slopes URBONB D* Soil Urban Land, Boonton Substratum, 0 to 8 percent slopes Description Runoff Curve Number (CN) Impervious Surface 98 Open Space (lawn) (good) 80 Woods 77 * Based on laboratory testing performed by Dynamic Earth, LLC, permeability rates were less that 0.01 inches per hour which is consistent with a hydrologic soil group (HSG) D. For the purposese of the design, the site has been modeled as HSG D in the Runoff Curve Number calculations.

TIME OF CONCENTRATION (Tc) CALCULATIONS

Date: 6/14/2022 Project: Altera Development Project No: 2530-99-006 1904 Main Street, Lake Como, NJ 07719 Calculated By: SDP (732) 974-0198 Checked By: RJC Worksheet 3: Time of Concentration (T c ) Calculations Land Condition: Existing Drainage Area: DA-1 • Sheet Flow : AB BC Woods, Light Woods, Light 1. Surface Description . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . Underbrush Underbrush 2. Manning's Roughness Coefficient, n . . . . . . . . . . . . . . . . . . . . . . 0.4 0.4 3. Flow Length, L { total L ≤ 100 ft } . . . . . . . . . . . . . . . . . . . . . . . 50.0 ft 50.0 ft 4. Two-Year 24-hour Rainfall, p 2 for . . . Essex County .... 3.44 in 3.44 in 3.44 in 5. Land Slope, s (ft/ft) . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 0.029 ft/ft 0.057 ft/ft 0.007 (n L ) 0.8 6. Travel Time, T t = 0.5 0.4 . . . . . . . . . . . . . . . . . . . . . . . 0.171 hr + 0.130 hr + 0.000 hr = 0.301 hr p2 s • Shallow Concentrated Flow :

30 hr + 0.000 hr = 0.301 hr p2 s • Shallow Concentrated Flow : BC CD EF 7. Surface Description . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . Unpaved Unpaved Unpaved 8. Flow Length, L . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 25.0 ft 37.0 ft 20.0 ft 9. Watercourse Slope, s . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 0.050 ft/ft 0.027 ft/ft 0.167 ft/ft 10. Average velocity, V { see Figure 3.1) . . . . . . . . . . . . . . . . . . . . . . 3.61 ft/s 2.65 ft/s 6.59 ft/s 11. Travel Time, T t = L . . . . . . . . . . . . . . . . . . . . . . . 0.002 hr + 0.004 hr + 0.001 hr = 0.007 hr 3600 V • Channel Flow : 12. Pipe Diameter, D . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 13. Cross-Sectional Flow Area, A . . . . . . . . . . . . . . . . . . . . . . . . . 14. Wetted Perimeter, p w . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 15. Hydraulic Radius, r = A / p w . . . . . . . . . . . . . . . . . . . . . . . . . . 16. Channel Slope, s . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 17. Pipe Material . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 18. Manning's Roughness Coefficient, n . . . . . . . . . . . . . . . . . . . . . 2/3 1/2 1.49 r s 19. Velocity, V = ..................... n 20. Flow Length, L . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 21. Travel Time, T t = L . . . . . . . . . . . . . . . . . . . . . . . . 0.000 . . . . . hr

. . . . . . . . . . . . . . . . . . . . . . . . 0.000 . . . . . hr ...+ . . . 0.000 . . . hr + 0.000 hr = 0.000 hr 3600 V 22. Watershed or subarea Time of Concentration, T c { add T t in steps 6, 11 and 21 } . . . . . . . . . . . . . . . . . . . . . . . . . 0.308 hr 18.5 min

Date: 6/14/2022 Project: Altera Development Project No: 2530-99-006 1904 Main Street, Lake Como, NJ 07719 Calculated By: SDP (732) 974-0198 Checked By: PAF Worksheet 3: Time of Concentration (T c ) Calculations Land Condition: Existing Drainage Area: DA-2 • Sheet Flow : AB BC CD Woods, Light Woods, Light 1. Surface Description . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . Underbrush Underbrush Woods, Light Underbrush 2. Manning's Roughness Coefficient, n . . . . . . . . . . . . . . . . . . . . . . 0.4 0.4 0.4 3. Flow Length, L { total L ≤ 100 ft } . . . . . . . . . . . . . . . . . . . . . . . 25.0 ft 43.0 ft 32.0 ft 4. Two-Year 24-hour Rainfall, p 2 for . . . Essex County .... 3.44 in 3.44 in 3.44 in 5. Land Slope, s (ft/ft) . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 0.220 ft/ft 0.023 ft/ft 0.188 ft/ft 0.007 (n L ) 0.8 6. Travel Time, T t = 0.5 0.4 . . . . . . . . . . . . . . . . . . . . . . . 0.044 hr + 0.166 hr + 0.057 hr = 0.266 hr

. . . . . . . . . . . . . . . . . . . . . . . 0.044 hr + 0.166 hr + 0.057 hr = 0.266 hr p2 s • Shallow Concentrated Flow : DE EF FG 7. Surface Description . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . Unpaved Unpaved Unpaved 8. Flow Length, L . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 36.0 ft 15.0 ft 12.0 ft 9. Watercourse Slope, s . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 0.250 ft/ft 0.133 ft/ft 0.083 ft/ft 10. Average velocity, V { see Figure 3.1) . . . . . . . . . . . . . . . . . . . . . . 8.07 ft/s 5.89 ft/s 4.65 ft/s 11. Travel Time, T t = L . . . . . . . . . . . . . . . . . . . . . . . 0.001 hr + 0.001 hr + 0.001 hr = 0.003 hr 3600 V • Channel Flow : 12. Pipe Diameter, D . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 13. Cross-Sectional Flow Area, A . . . . . . . . . . . . . . . . . . . . . . . . . 14. Wetted Perimeter, p w . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 15. Hydraulic Radius, r = A / p w . . . . . . . . . . . . . . . . . . . . . . . . . . 16. Channel Slope, s . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 17. Pipe Material . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 18. Manning's Roughness Coefficient, n . . . . . . . . . . . . . . . . . . . . . 2/3 1/2 1.49 r s 19. Velocity, V = ..................... n 20. Flow Length, L . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 21. Travel Time, T t = L . . . . . . . . . . . . . . . . . . . . . . . . 0.000

. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 21. Travel Time, T t = L . . . . . . . . . . . . . . . . . . . . . . . . 0.000 . . . . . hr ...+ . . . 0.000 . . . hr + 0.000 hr = 0.000 hr 3600 V 22. Watershed or subarea Time of Concentration, T c { add T t in steps 6, 11 and 21 } . . . . . . . . . . . . . . . . . . . . . . . . . 0.269 hr 16.1 min