2025 12 19 Stormwater Report Rev 1

0.012 0.023 0.007 0.012 0.023 0.000 0.000 0.000 1398 0.007 0.012 0.023 0.007 0.012 0.023 0.000 0.000 0.000 1404 0.007 0.012 0.022 0.007 0.012 0.022 0.000 0.000 0.000 1410 0.007 0.012 0.022 0.007 0.012 0.022 0.000 0.000 0.000 1416 0.007 0.012 0.022 0.007 0.012 0.022 0.000 0.000 0.000 1422 0.007 0.012 0.022 0.007 0.012 0.022 0.000 0.000 0.000 1428 0.007 0.011 0.022 0.007 0.011 0.022 0.000 0.000 0.000 1434 0.007 0.011 0.021 0.007 0.011 0.021 0.000 0.000 0.000 1440 0.007 0.011 0.021 0.007 0.011 0.021 0.000 0.000 0.000 1446 0.005 0.009 0.017 0.005 0.009 0.017 0.000 0.000 0.000 1452 0.003 0.004 0.008 0.003 0.004 0.008 0.000 0.000 0.000 24 of 24

,@ o APPENDIX

Chapter 2 Estimating Runoff and Peak Part 650 Discharges Engineering Field Handbook NJ Supplement NEW JERSEY 24 HOUR RAINFALL FREQUENCY DATA Rainfall amounts in Inches County Tyear 2year Syear {Oyear 25 year SOyear 100year Atlantic 2.72 3.31 4.30 5.16 6.46 7.61 8.90 Bergen 2.75 3.34 427 5.07 6.28 7.32 8.47 Burlington 2.77 3.36 4.34 5.18 6.45 7.58 8.81 Camden 2.73 3.31 4.25 5.06 6.28 7.34 8.52 Cape May 2.67 3.25 4.22 5.07 6.34 7.47 8.73 Cumberland 2.69 3.27 425 5.09 6.37 7.49 8.78 Essex 2.85 3.44 4.40 5.22 6.44 7.49 8.66 Gloucester 274 3.29 4.24 5.05 6.29 7.36 8.55 Hudson 2.73 3.31 4.23 5.02 6.19 7.20 8.31 Hunterdon 2.80 3.38 4.26 5.00 6.09 7.02 8.03 Mercer 2.74 3.34 4.23 5.01 6.19 7.20 8.33 Middlesex 2.76 3.35 4.30 5.12 6.36 7.43 8.63 Monmouth 2.79 3.38 4.38 5.23 6.53 7.66 8.94 Mortis 2.94 3.54 4.47 5.24 6.37 7.32 8.35 Ocean 2.81 3.42 4.45 5.33 6.68 7.87 9,20 Passaic 2.87 3.47 4.42 5.23 6.43 747 8.62 Salem 2.69 3.26 4.20 §.00 6.22 7.28 8.45 Somerset 2.76 3.34 4.25 5.01 6.15 7.43 8.21 Sussex 2.68 3.22 4.02 4.70 5.72 6.60 7.58 Union 2.80 3.39 4.35 5.17 6.42 7.49 8.69 Warren 2.78 3.34 4.18 4.89 5.93 6.83 7.82 Notes: The average point rainfall amounts listed above were developed from data contained in NOAA Atlas [4 Volume 2. Point rainfall estimates for specific locations may be obtained from the Precipitation Frequency Data Server located at http://www.nws.noaa.zov/ohd/hdse/ For most hydrologic design procedures, the rainfall amounts listed above may be rounded to the nearest tenth of an inch. Page | of 2 August, 2012

Chapter 2 Estimating Runoff and Peak Part 650 Discharges Engineering Field Handbook NJ Supplement NEW JERSEY Rainfall Distribution Regions Regional Rainfall Distributions for use in EFH-2 and winTRSS For winTR20, use site specific rainfill distributions from NOAA Atlas 14 data Page 2 of 2 August, 2012

Chapter 2 Estimating Runoff Technical Retease 55 Urban Hydrology for Small Watersheds Table 2-2a Runoff curve numbers for urban areas / Curve numbers for a Cover description hydrologic soil group Average percent Cover type and hydrologic condition impervious area Y A B c D Fully developed urban areas (vegetation established) Open space (lawns, parks, golf courses, cemeteries, etc.) Poor condition (grass cover < 50%)..... 68 79 86 89 Fair condition (grass cover 50% to 75%) 49 69 8 84 Good condition (grass cover > 75%). 39 61 14 80 Impervious areas: Paved parking lots, roofs, driveways, etc. (excluding right-of-way) 98 98 98 98 Streets and roads: Paved; curbs and storm sewers (excluding right-of-way) . sesseeesees 98 98 98 98 Paved; open ditches (including right-of-way) 83 89 92 93 Gravel (including right-of-way) 76 85 89 OL Dirt (including right-of-way). 72 82 87 89 Western desert urban areas; Natural desert landscaping (pervious areas only) + . 63 WW 85 88 Artificial desert landscaping (impervious weed barrier, desert shrub with 1- to 2-inch sand or gravel mulch : and basin borders) ... 96 96 96 96 Urban districts: Coramercial and business .. 85 89 92 S4 95 Tadusttial .... 72 81 88 ot 93 Residential districts by average lot size: V8 acre or less (town houses) . 65 17 85 90 92 14 acre 38 61 75 83 87 1 acre 30 57 72 81 86 V2 acre 25 54 70 80 85 Jacre .. 20 51 68 79 84 2 acres. 12 46 65 7 82 Developing urban areas Newly graded areas (pervious areas only, no vegetation) ¥... 17 86 a1 o4 Idle lands (ON's are determined using cover types -_ similar to those in table 3-2c). } Average runoff condition, and I, = 0.28. 2 The average percent impervious area shown was used to develop the composite CN's. Other assumptions are as follows: impervious areas are directly connected to the drainage system, impervious areas have a CN of 98, and pervious areas are considered equivalent to open space in good hydrologic condition. CN's for other combinations of conditions may be computed using figure 2-3 or 2-4, 3 CN's shown are equivalent to those of pasture. Composite CN's may be computed for other combinations of open space cover type. | Composite GN’s for natural desert landscaping should be computed using figures 23 or 2-4 based on the impervious area percentage (CN = 98) and the pervious area CN. The pervious area CN's are assured equivalent ta desert shrub in poor

landscaping should be computed using figures 23 or 2-4 based on the impervious area percentage (CN = 98) and the pervious area CN. The pervious area CN's are assured equivalent ta desert shrub in poor hydrologic condition, 5 Composite CN's ta use for the design of temporary measures during grading and construction should be computed using figure 23 or 2-4 based on the degree of development (impervious area percentage) and the CN's for the newly graded pervious areas. (210-V-TR-5, Second Ed., June 1986)

Chapter 2 Estimating Runoff Technical Release 55 Urban Hydrology for Small Watersheds Table 2-2c — Runoff curve numbers for other agricultural lands Y Curve numbers for Cover description hydrologic sof group Hydrologic Cover type condition A B c D Pasture, grassland, or range—continuous Poor 68 79 86 a9 forage for grazing. ¥ Fair 49 69 2) 84 Good 39 61 4 80 Meadow—continuous grass, protected from - 30 58 1 B grazing and generally mowed for hay. Brush—brush-weed-grass mixture with brush Poor 48 67 7 83 the major element. ¥ Fair 35 56 70 7 Good 304 48 65 73 Woods—grass combination (orchard Poor 57 vid 82 86 or tree farm). 9 Fair 43 65 76 82 Good 32 58 72 9 Woods. ¥ Poor 45 66 7 Fair 36 60 3 9 Good 302 55 7 7 Farmsteads—buildings, lanes, driveways, —_ 59 14 82 86 and surrounding lots. erage runoff coruition, and I, = 02S. A 2 Poor: <50%6) ground cover or heavily grazed with no mulch. Fair: 50 to 75% ground cover and not heavily grazed. Good: > 75% ground cover and lightly or only occasionally grazed. > Poor. <50% ground cover. Fair: 50 to 76% ground cover. Good: >75% ground cover. 4 Actual curve number is tess than 30; use CN = 90 for runoff computations. 5 CW's shown were computed for areas with 50% woods and 50% grass (pasture) cover. Other combinations of conditions may be computed from the CN’s for woods and pasture. © Poor: Forest litter, small trees, and brush are destroyed by heavy grazing or regular burning. Fair: Woods are grazed but not bumed, and same forest litter covers the soil. Good: Woods are protected from grazing, and litter and brush adequately cover the soll. (210-V1-TR-5S, Second Ed, June 1986) a7

Table 10-4 Recommended Coefficient of Runoff Values NOTE: Values are based on NRCS (formerly SCS) definitions and are average values. Source: Technical Manual for Land Use Regulation Program, Bureau of Inland and Coastal Regulations, NJDEP Flood Hazard Area Permits, New Jersey Department of Environmentat Protection for Various Selected Land Uses Land Use Description Cultivated Land thout conservation treatment | 0.- a 0.670.681] 0.88 ith conservation treatment 0.27 [0.439] 0.67|] 0.67 Pasture or Range Land condition 0.38 [0.63]0.78] 0.84 Meadow condition 0. pag 0.53] 0.65 condition 0.43] 0.61 [Wood or Forest Land in stand, poor cover, no mulch 0.34]]0.59]) 0.70 0.45] 0.59 n Spaces, Lawns, Pari If Courses, Cometeries Condition Fass Cover on 75% or more o> 90.2570.52] 0.65 Fair Condition Fass Cover on 50% to 75% -- JO45170.639 0.74 Commercial and Busi 5% impervious 0.84 ]0.90/0.93) 0.96 jArea industrial Districts |z2% impervious 0.67 Jlo.81 Oss} 0.92 Residential erage % impervious JAverage Lot Size (acres) Vs 5s 0.59 10.76 10.86) 0.90 4 8 0.29 10,55 10.70} 0.80 1/3 0 vr 10.49 70.67) 0.78 2 5 sr FO4570.65] 0.76 L 0 w> $0.41 90.63] 0.74 ta Areas Ee lots, roofs, driveways, | 0.99 |lo.99]/0.99] 0.99 c. [Streets and Roads ed with curbs & storm 0.99 10.9990.99] 0.99 0.57 10.76 )0.84] 0.88 ravel 0.49 10.6970.80] 0.84 rt

FIGURE 10-B: RAINFALL INTENSITY-DURATION FREQUENCY CURVE - NORTHERN REGION DURATION OF STORM IN MINUTES 10 15 20 30 40 5060 120 180 19.0 | 8.0 |! 7.0 + 6.0=> 50S [,, | ISS 5 4.0 “™~ SS < = ‘a ae SASS : P ~ RS, 5 SS RS N F3 ARS Re : v NISSN %, |o N <A a SANS e INS 3 1.0 a SZ 0.9 0.8 ® 0.7 0.6 0.5 0.4 PARED QW: coal svat 7 le poss arias ih ob 2005 ILYEAR AND 15-YEAR oe ee | | 10 15 20 30 40 5060 120 180 DURATION OF STORM IN MINUTES

Time of Concentration Calculations Project #: 24-170 Pre-Development Project: The Estate Post-Development County: Essex Drainage Area: DA-1 Sheet Flow Segment 1 Segment 2 Segment 3 Surface Description (Table 3-1) Grass, Dense Grasses Grass, Dense Grasses Manning's Roughness Coeff., n (Table 3-1) 0.24 0.24 - Flow Length, L (total ≤ 100 ft) 20 80 Two-Year 24-Hour Rainfall, P2 (CA) 3.47 3.47 3.47 Two-Year 24-Hour Rainfall, P2 (FP) 4.09 4.09 4.09 Land Slope, s (ft/ft) 0.025 0.05 Tt (CA) 3.5 7.9 - 11.4 Tt (FP) 3.2 7.3 - 10.5 Shallow Concentrated Flow Segment 1 Segment 2 Segment 3 Surface Description Unpaved paved paved Flow Length, L 70 340 120 Watercourse Slope, s (ft/ft) 0.05 0.05 0.025 Average Velocity 3.6 4.6 3.2 Tt 0.3 1.2 0.6 2.2 Channel Flow Segment 1 Segment 2 Segment 3 Cross Sectional Flow Area, a Wetted Perimeter, Pw Hydraulic Radius, r - - - Channel Slope, s (ft/ft) Manning's Roughness Description Manning's Roughness - - - Velocity - - - Flow Length Tt -