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

WEIGHTED RUNOFF COEFFICIENT CALCULATIONS

Crestmont Country Club Eagle Rock Ave Improvements Langan Project #10104802 Township of West Orange, NJ DRAINAGE SUBAREA RUNOFF COEFFICIENT CALCULATIONS PROPOSED STORMWATER CONVEYANCE DESIGN CRESTMONT COUNTRY CLUB & EAGLE ROCK AVE IMPROVEMENTS LANGAN PROJECT #10104802 PROPOSED CONVEYANCE SYSTEM SUB- OPEN SPACE OPEN SPACE WOODS GRAVEL IMPERVIOUS TOTAL TOTAL RUNOFF DRAINAGE HSGC C HSGC D HSGC C HSGC C AREA AREA AREA COEFFICIENT STRUCTURE AREA C = 0.51 C = 0.65 C = 0.45 C = 0.84 C = 0.99 C TYPE (SF) (SF) (SF) (SF) (SF) (SF) (AC) (Weighted) NETWORK 1 CB1-1 0 170 0 0 3,228 3,397 0.08 0.97 GRATE INLET CB1-2 0 538 0 0 4,111 4,649 0.11 0.95 GRATE INLET CB1-3 0 28 0 0 1,516 1,544 0.04 0.98 GRATE INLET CB1-4 0 911 0 0 5,583 6,493

0.04 0.98 GRATE INLET CB1-4 0 911 0 0 5,583 6,493 0.15 0.94 GRATE INLET CB1-5 299 0 0 0 5,911 6,210 0.14 0.97 GRATE INLET CB1-6 0 1,263 0 0 2,061 3,324 0.08 0.86 GRATE INLET CB1-7 (SWALE 1) 12,719 14,998 26,663 0 51,764 106,144 2.44 0.75 GRATE INLET CB1-8 0 1,392 0 0 1,395 2,787 0.06 0.82 GRATE INLET CB1-9 0 469 0 0 1,511 1,980 0.05 0.91 GRATE INLET CB1-10 0 982 0 0 910 1,892 0.04 0.81 GRATE INLET CB1-11 0 0 0 0 860 860 0.02 0.99 GRATE INLET CB1-12 0 4,023 0 0 0 4,023 0.09 0.65 GRATE INLET CB1-13 23,541 0 13,477 3,739 8,953 49,710 1.14 0.61 GRATE INLET CB1-14 0 1,302 0 0 600 1,902 0.04 0.76 GRATE INLET CB1-15 135 0 0 0 4,053 4,188 0.10

0.76 GRATE INLET CB1-15 135 0 0 0 4,053 4,188 0.10 0.97 GRATE INLET CB1-16 0 380 0 0 5,234 5,614 0.13 0.97 GRATE INLET CB1-17 2,265 820 0 0 6,372 9,457 0.22 0.85 GRATE INLET CB1-18 1,434 497 0 0 1,460 3,390 0.08 0.74 GRATE INLET CB1-19 390 0 0 0 15,512 15,901 0.37 0.98 GRATE INLET CB1-20 305 1,105 0 0 12,028 13,438 0.31 0.95 GRATE INLET CB1-21 0 1,763 0 0 1,138 2,901 0.07 0.78 GRATE INLET CB1-22 0 0 0 0 7,887 7,887 0.18 0.99 GRATE INLET CB1-23 0 1,502 0 0 3,000 4,502 0.10 0.88 GRATE INLET CB1-24 0 1,025 0 0 1,575 2,600 0.06 0.86 GRATE INLET CB1-25 0 1,140 0 0 1,863 3,003 0.07 0.86 GRATE INLET CB1-26 0 1,497 0 0 2,291 3,788 0.09 0.86

GRATE INLET CB1-26 0 1,497 0 0 2,291 3,788 0.09 0.86 GRATE INLET CB1-27 0 919 0 0 2,786 3,705 0.09 0.91 GRATE INLET CB1-28 0 622 0 0 1,841 2,463 0.06 0.90 GRATE INLET CB1-29 0 675 0 0 1,950 2,625 0.06 0.90 GRATE INLET CB1-30 0 761 0 0 1,839 2,600 0.06 0.89 GRATE INLET CB1-31 3,812 0 0 0 0 3,812 0.09 0.51 GRATE INLET CB1-32 0 1,526 0 0 2,284 3,810 0.09 0.85 GRATE INLET CB1-33 81 7,209 0 0 5,357 12,647 0.29 0.79 GRATE INLET CB1-34 0 1,217 0 0 1,800 3,017 0.07 0.85 GRATE INLET CB1-35 0 1,325 0 0 1,285 2,610 0.06 0.82 GRATE INLET CB1-36 0 1,479 0 0 1,149 2,628 0.06 0.80 GRATE INLET CB1-37 (SWALE 2) 2,181 3,915 1,185 0 0 7,281 0.17 0.58 GRATE INLET

1-37 (SWALE 2) 2,181 3,915 1,185 0 0 7,281 0.17 0.58 GRATE INLET CB1-38 2,140 803 987 0 12,442 16,372 0.38 0.88 GRATE INLET MH1-17 0 0 0 0 15,268 15,268 0.35 0.99 MANHOLE EX-CB1-1 0 1,205 0 0 1,298 2,503 0.06 0.83 GRATE INLET EX-CB1-2 33,066 4,704 0 0 21,788 59,558 1.37 0.70 GRATE INLET EX-CB1-3 0 0 0 0 11,824 11,824 0.27 0.99 GRATE INLET EX-CB1-4 0 0 0 0 1,686 1,686 0.04 0.99 GRATE INLET EX-CB1-5 610 991 6,281 0 2,447 10,329 0.24 0.60 GRATE INLET EX-CB1-6 0 49 1,972 0 200 2,221 0.05 0.50 GRATE INLET EX-CB1-7 161 530 241 0 857 1,789 0.04 0.77 GRATE INLET EX-CB1-8 670 842 10,344 0 0 11,855 0.27 0.47 GRATE INLET NOTES: 1. Runoff coefficients are referenced from Table 10.3-B: Recommended Coefficient of Runoff Values for Various Selected Land Uses from Section 10 of the 2015 New Jersey Department of Transportation (NJDOT) Roadway

efficients are referenced from Table 10.3-B: Recommended Coefficient of Runoff Values for Various Selected Land Uses from Section 10 of the 2015 New Jersey Department of Transportation (NJDOT) Roadway Design Manual. \\langan.com\data\PAR\data8\101049801\Project Data\_Discipline\Site Civil\Stormwater\Eagle Rock Inlet Runoff Coefficient Calculations

TIME OF CONCENTRATION CALCULATIONS

CB1-7 (SWALE 1)

Project: Eagle Rock Avenue By: TEG Date: 10/22/2025 Location: West Orange, NJ Checked By: MJV Date Checked: 10/22/2025 Circle One: Present Developed Inlet CB1-7 (Swale 1) Circle One: Tc Tt through subarea Include a map, schematic, or description of flow segments. Sheet Flow (Applicable to Tc Only) Segment ID 1 2 Woods Light Woods Light 1. Surface Description (NEH table 15-1) Underbrush Underbrush 2. Manning's Roughness Coeff., n (NEH table 15-1) 0.40 0.40 3. Flow Length, L (total L < 100 ft) ft 67 23 4. Two-year 24-hr rainfall, P2 in 3.43 3.43 5. Land Slope, s ft/ft 0.068 0.505 6. Compute Tt 0.007 (nL)0.8 hr 0.154 + 0.029 + Tt = P20.5s0.4 Sheet Flow Sub-Total 0.183 hours Shallow Concentrated Flow Segment ID 3 Grassed 7. Surface Description Waterways 8. Flow Length, L ft 13 9. Watercourse Slope, s ft/ft 0.372 10. Average Velocity, V (NEH table 15-3)