SAG INLET DESIGN WORKSHEET
Combination inlet at low point
660+10
Statio 661+10
661+53
662+05
663+50 Inlet Elevation
11/9/2009
Inlet Elevation
Inlet Elevation
Transverse Slope Allowable Allowable
ST Zd dB Tc m n I50-yr L1
0.020 12.00 0.24 5.0 8.28 0.567 3.32
ft/ft ft ft min
Shoulder Width
Inlet Elevation
6.00
ft ft
Lane Width 12.00 (dA = dC = 0.12 ft allowable)
Time of Concentration
Rainfall Intensity
in/hr ft ft cfs cfs
(for 5 minute duration) L2 W2 QBP24 Q2 197.00 24.50 0.24 0.35 ft ft cfs cfs
153.00 24.50 0.28 0.27
Width of catchment area Bypass from last inlet Discharge of catchment area
W1 QBP14 Q1
50 yr. BP1 + Q1 QTotal = Qrainfall + QBP2 + Q2
coefficients
QTotal = 0.28 + 0.27 + 0.24 + 0.35 = 1.14 cfs
Distance between sag inlet Combination1 or Grate Inlet for last PB (C/G) . PA Flank
PB PC SQ = QA + QB + QC
2 Flank
C 0 3.87 0
ft ft ft
Width Width Width
0 1.31 0
Length Length Length
0 1.25 0
SQ = CWAPA(0.5dB)1.5 + CWBPBdB1.5 + CWCPC(0.5dB)1.5
1.37
cfs
Capacity is adequate, design is complete. Check calculated dB against allowable dB.
0.21 If dB < allowable dB, the design is complete. If dB > allowable dB, additional inlets must be added3 and the process repeated.
ft
1 2
Notes: Grate Inlets (reduced by
If using a combination inlet for the sag, the flank grate inlets are not required except in a depressed area (See Hydaulics Manual). 50% for plugging) Formulas based on weir flow. See Hydraulic Manual 5-5.2. XL1024 388c7341-8c1e-4279-a319-34ff2d705315.xls
Effective Perimeter of
Inlet Elevation
Statio
Statio
Statio
Statio
3
4
To add more than one inlet in the sag or flanks just increase the width and length values to the sum of all values. Inlets can be different sizes. See Figure 5-5 in Hydraulics Manual for grate dimensions. Qbp1 and Qbp2 come from the inlet spreadsheet.
XL1024
388c7341-8c1e-4279-a319-34ff2d705315.xls
11/9/2009