12 2026 02 12 Crestmont CC Stormwater Management Report

Basin Emergency Spillway Basin: SSBB-2 Project: 101049802 The basin will use a spillway over the proposed berm to serve as a means of emergency overflow. Date: 10/17/2025 The spillway has been designed to convey the 100-year storm event design flow entirely through the spillway with a maximum flow depth. The following calculations demonstrate the adequacy of the spillway: 1. Qreq for the 100yr + 50% Flow = 34.04 CFS z= 3.00 100-yr Elev. = 539.63 2. Spillway Capacity = Qdesign OCS Grate Elevation = 540.67 C = Weir Coefficient = 3.00 L = Weir Length = 60.00 H = Flow Depth = 0.33 Freeboard =

H = Flow Depth = 0.33 Freeboard = 1.00 3/2 Q = CLH Q (cfs) = 34.12 34.12 > 34.04 GOOD 3. Top of the Crest Elevation = 540.67 4. Top of the Berm Elevation = 542.00 Top Width (ft) = 68.00 AREA (SF)= 20.13 Freeboard = 1.00 VELOCITY (ft/s)= 1.69 Top of the Bank = 542.00 1 541.00 Depth = 0.33 Top of the Crest = 540.67 z= 3 100-yr Elev. = 539.63

Freeboard = 1.04 Length = 60.00 Shear Stress Calculation Variables τd = 62.4 (d*S) Vmax C350 Shear Stress Capacity 12 lb/ft2 Channel Bed Slope S 0.33 ft/ft Vmax C350 Maximum Allowable Velocity 20 ft/sec Depth of Water d 0.50 ft τd = 10.296 lb/ft2 Pass VMAX = 1.69 ft/sec Pass Over Spillway Filter Filter Velocity Median Stone d50 Size Thickness *d (ft/s) Size (in) (in) NSA-No. NSA-No. (in) d 1.69 C350 N/A N/A N/A N/A

N/A N/A N/A N/A *d = 1.5 times the maximum stone diameter but not less than 6 inches. Discharge Curve 40.00 Discharge (CFS) 34.12 30.00 20.00 22.16 22.16 16.86 16.86 10.00 12.06 12.06 4.27 7.84 7.84 4.27 0.00 0.00 1.51 1.51 0.00 540.67 540.71 540.75 540.79

540.75 540.79 540.83 540.87 540.91 541.00 540.91 540.87 540.83 540.79 540.75 540.71 540.67

540.67 Elevations (FT) \\langan.com\data\PAR\data8\101049801\Project Data\_Discipline\Site Civil\Stormwater\Eagle Rock Emergency Spillway Worksheet 10/21/2025 @ 3:47 PM

ANTI-SEEP COLLAR CALCULATIONS

SMALL-SCALE BIORETENTION BASIN 1

ANTI-SEEP COLLAR DESIGN PROJECT NAME: Crestmont Country Club & Eagle Rock Ave Improvements PROJECT LOCATION: West Orange, New Jersey BASIN ID# SSBB-1 DONE BY: TEG DATE: 10/17/25 CHECKED: MJV DATE: 10/17/25 OUTLET PIPE: INVERT UPSTREAM (Yup) 530.25 INVERT DOWNSTREAM (Ydn) 526.80 PIPE RISE: 18 inches PIPE SPAN: 18 inches PIPE LENGTH: 47 ft PIPE SLOPE (So): 0.073 100-YEAR BASIN ELEV. (Y100): 536.73 EMBANKMENT SLOPE (Z): 1 (EXAMPLE 3:1 SLOPE -> Z=3) CALCULATIONS: Y=Y100-Yup= 6.48 Lsz=Y(Z+4)*(1+(So/0.25-So))= 39.53 ft SAFETY FACTOR Lsz*1.15= 45.47 ft USE Lsz= 45.00 ft SPACING DESIGN: COLLAR WIDTH(OR DIAM.): 7.00 ft NO. OF COLLARS REQ.: 0.30 =(L-Lsz)/2*collar width USE 1.00 collars MAX. SPACING ALLOWED: 14.00 ft =14ft*no. of collars CALCULATED SPACING: 39.53 ft =Lsz/(no. of collars) USE LESSER OF MAX. OR 14.00 CALCULATED SPACING: ft COLLAR DIMENSIONS FOR OUTLET PIPE: USING RECTANGULAR COLLARS, THE DIMENSION OF THE HEIGHT SHOULD BE: 7.00 ft =2*2'+pipe rise WIDTH SHOULD BE: 7.00 ft =2*2'+pipe span THICKNESS TO BE: 12 inches

SMALL-SCALE BIORETENTION BASIN 2