24647 Seaview Tce Enviro Mgmt Plan

Sediment Basin Spillway Design Information
Peak Flow
Qy = (Cy x Itc,y x A)/360         Equation 1 (IECA 2008)
Where:
Qy=                  Peak flow rate (m3/s) of average recurrence interval (ARI) of Y years
Cy=                  runoff coefficient (dimensionless) for ARI of Y years                                                                                                                                                                                                                                                                                         Job No. 17SUN-0024
Itc,y=               Average rainfall intensity (mm/hr) for design duration of tc hours and ARI of Y years.                                                                                                                                                                                                                                                          Client HUTCHINSON
A=                   Area of catchments (ha)                                                                                                                                                                                                                                                                                                                            Job 71 SEAVIEW TERRACE
360=                 Conversion Factor                                                                                                                                                                                                                                                                                                                                Date 3/8/2016

Wier (Minor friction loss over spillway crest and approach channel)                                             Refer to Figure 1
Water level in sediment basin solved using equation below using trail and error.
Q = 1.7bH1.5 + 1.26mH2.5         Equation 2 (IECA 2008)                                                                                                                                                                          H
                                                                                                                                                               1
Where
Q=                   Peak flow rate (m3/s) of average recurrence interval (ARI) of Y years (calculated using Equation 1)
b=                   Base width of wier                                                                                                                                   m
H=                   Water level within Sediment Basin relative to spillway (weir) crest (m)
                                                                                                                                                                                                                         b
                                                                                                                                                                                                    Figure 1 Wier Profile
Chute                                                                                                           Refer to Figure 2
Flow height is solved by trial and error using the three equations below as per IECA 2008.
Q = 1/n x A x R2/3 x S1/2          Equation 3 (IECA 2008)
Where
Q=                   Peak flow rate (m3/s) of average recurrence interval (ARI) of Y years
n=                   Mannings coefficieint (unitless)
A=                   Cross sectional area of flow (m2), refer to Eqaution 4
R=                   Hydraulic Radius (m), refer to Equation 5
S=                   Slope of energy line, equal to slope of chanel bed (m/m)

A = (b + xy)y                     Equation 4 (IECA 2008)
Where
A=                   Cross sectional area of flow (m2)
b=                   Base width of channel (m)
x=                   side slope of channel
y=                   depth of flow in channel (m) + required 0.30m freeboard

R = ((b + xy)y) / (b+2y(1+x2)1/2) Equation 5 (IECA 2008)
Where
R=                   Hydraulic radius of flow (m)                                                                                                Figure 2 Cross-section of Chute
b=                   Base width of channel (m)
x=                   side slope of channel
y=                   depth of flow in channel (m) + required 0.30m freeboard

Energy Dissipator                                                                                               Refer to Figure 3
d50                  Median Rock Diametre (mm) Table 5 of IECA 2008 Fact Sheet "Chutes Part 1"                                                                                                                                                                                      Figure 3 Energy Dissipator
W1=                  Width 1 (m)=(b+2xy)+0.6
W2=                  Width 2 (m)=(b+2xy)+0.4L
L=                   Length of dissipator (m) Table 6 of IECA 2008 Fact Sheet "Chutes Part 1"                                                                                                             R calculation & Velocity Check
                                                                                                                                                        Base            Batter          Depth                     Area (m²)      P (m)      R                      D50         Velocity           Max V
                                                                                                                                           Total Site (compacted)   5               2                      0.021        0.105882 5.09391486                 0.02         200               1.78               2.23
                                                                                                                                                        0           0               2             #N/A                  #N/A               #N/A         #N/A             200       #N/A                       2.23
                                                                                                                                                        0           0               2             #N/A                  #N/A               #N/A         #N/A             200       #N/A                       2.23
                                                                                                                                                        0           0               0                       0.000                    0             0   #DIV/0!           200               0.00               2.23




                                   Peak Flow (Entering Basin)                                                 Wier                                                                                                      Chute                                                                                                                 Energy Disipator
                                                                                                                                Minimum                                                                                                                       Required
                                                                                                                 Upstream                                                                                                                                       Chute    Maximum
                                                                                                Horizontal                     Height with
                                                                                 Base width                      water level               Channel                       Channel                                                                             Depth with Permissable
 Sediment Basin                                                                                  Slope of                        0.30m
                                                                                    (m)                          relative to
     Label                  C50     Itc,y      Tc         A           Q20
                                                                                                   Wier                        Freeboard Base Width Side Slope            Slope                                                                      Flow      300mm      Velocity                  Velocity         Mean rock size, d50
                                                                                                                  Wier (m)                   (m)      Length              (m/m)         Proposed Lining              Mannings            Peak Flow Depth (m) Feeboard      (m/s)                     (m/s)                 (mm)            Width 1 (m)     Width 2 (m)       Length (m)
                                                                                                                                   (m)
                                                                                                                                  H+
                                                                                       b             m                H
                                                                                                                               freeboard        b              x              So                                             n              Q             y         y+0.3m         Vmax                   V                 d50                W1                 W2              L
Total Site (compacted) 1.012        291        5              0.23    0.19           5.00           2.00             0.07         0.37         5.00            2           0.2500       Coir Mat TMC7                  0.0220              0.188       0.021         0.321          3.30             1.78                 100.000             5.684              5.484          1.000
                                                                                                                       -        #VALUE!        0.00            2           0.2500       Rock R200, D100 (0.5)          0.0600              0.000       #N/A          #N/A           1.58             #N/A                  #N/A               #N/A               #N/A           #N/A