Pre-Request Response Application 132001.210310.1

B2: CONCEPT DETENTION BASIN DESIGN CALCULATIONS                                                                     -
                                                                                                                        TWIGRUSH BIO-BASIN

File:             H:\809\150-199\B09182.w\Stormwater\[B09182.w RM.xls)OSD_SSC design TWIG RUSH
Date:             29/10/2011
User:             MS
Note:             SSD Relationship for Twigrush Bio Retention Basin


STAGE       -    STORAGE RELATIONSHIP FOR WBNM
StaQe areas taken from ACAD model
                                                    Accumulated

      RL           Area (m2)         Vol. (m3)       Vol. (m3)

            7.5             468          0              0
        7.75                471         117            117
            7.9         539.4           76             193
             8               585        56             249
            8.2             589         117            367
        8.25                590         147    .

                                                       396
            8.4             593         89             485
            8.5             595         59             545
        8.75                601         150            694
             9              608         151            845
            9.1          610.8          61             906
        9.25                615         92             998
            9.3          616.6          31             1029
            9.5             623         124            1153
            9.6         .626.2          62             1215




                                                     Circular         Circular
                                                      Inlet 1          Inlet 2




No.
Dia(m)
Height(m)
Area    (m2)
Invert Level (RL)
Inflow Level (RL)
D/S HGL (RL)
 (Fig 1.6)
Pit Loss (I<)
Hyd Condo (k)(m/hr)
Depth Media d (m)
Perimeter (m)



STAGE        -   DISCHARGE RELATIONSHIP FOR WBNM


                  Accumulated      Bio Filtration    Circular         Circular                                                        WEIR
      RL            VOI.(m")           Basin          Inlet 1          Inlet 2        WEIR1                PIPE 1        PIPE2    Overflow    TOTAL
      7.5               0             0.023           0.000            0.000           0.000                0.000        0.000        0.000   0.000
   7.75                117            0.033           0.000            0.000           0.000                0.000        0.000        0.000   0.033
      7.9              193            0.039           0.000            0.000           0.000                0.000        0.017        0.000   0.056
        8              249            0.043           0.000            0.000           0.000                0.000        0.052        0.000   0.095
      8.2              367            0.051           0.000            0.000           0.000                0.000        0.115        0.000   0.165
   8.25                396            0.053           0.000            0.000           0.000                0.000        0.123        0.000   0.176
      8.4              485            0.059           0.000            0.000           0.000                0.000        0.148        0.000   0.206
      8.5              545            0.062           0.000            0.000           0.000                0.000        0.163        0.000   0.225
   8.75                694            0.072           0.000            0.000           0.000                0.000        0.198        0.000   0,270
        9              845            0.082           0.000            0.000           0.000                0.000        0.229        0.000   0.311
      9.1              906            0.086           0.000            0.000           0.189                0.864        0.241        0.000   0.515
   9.25                998            0.092           0.000            0.000           0.601                0.897        0.258        0.000   0.950
      9.3              1029           0.094           0.000            0.000           0.658                0.908        0.263        0.000   1.015
      9.5              1153           0.101           0.000            0.000           0.850                0.952        0.285        0.742   1.979


Note:
The following equations have been used to calculate flow capcaties for the
outlet types for each stage:
Sand Filter Equation (NSW EPA 1997)                               o    ;A x k(h+d) 1 d

Pipe Flow (M.J.Boyd 1972)                                         0;0.421 X gO.5 x Diao.87 x HW1.63 (where HW/Dia < 1.2)
                                                                                             1.87
                                                                  0;0.53 X gO.5 x Dia               x   HWO.63 (where HW/Dia > 1.2)
                                                                  where g   ;    9.81 m/s2
Weir Equation (AR&R Equ. 14.5)                                    Oi   ;1.66 x P x d1.5

Orifice Equation (AR&R Equ. 14.6)                                 Oi   ;0.67 x A x (2g X      d)0.5
HGL Calculation (as per Section 5.21 OUDM)