Attachment 4 - Stormwater Managment Plan

SQIDEP Evaluation                                                                      SPEL Basin, Sippy Downs


Table 2 Comparison of Concentrations and Antecedent Conditions

                                                                Antecedent
                                                                               TSS                   TN
                                                                Dry Period             TP (mg/L)
                                                                              (mg/L)               (mg/L)
                                                  Date             (Hrs)
                                                   13/06/2017      13        107.00      0.16      2.30


                      SHORT ADWP (<24Hrs)
                                                    7/07/2017      11        256.00      0.55      8.90
                                                    8/07/2017      11        196.00      0.24      2.30
                                                   23/09/2017      11        142.00      0.24      3.00
                                                    3/10/2017      11         72.00      0.08      0.70
                                                   21/11/2017      13         61.00      0.04      0.40
                                                   22/11/2017      11         22.00      0.04      0.10
                                                   29/11/2017      11         34.00      0.04      0.10
                                            AVERAGE                          111.25      0.17      2.23
                                                   29/03/2017      14         42.00      0.04      0.40
           MEDIUM


           <100Hrs)
           (>24Hrs,
            ADWP




                                                   12/11/2017      37        176.00      0.15      0.70
                                                    4/03/2017      51         30.00      0.04      0.50
                                            AVERAGE                           82.67      0.08      0.53
                                                   14/03/2017      267        25.00      0.03      0.20
                      LONG ADWP (>100Hrs)




                                                   20/03/2017      146       1130.00     1.00      7.30
                                                   18/05/2017      242       134.00      0.11      1.40
                                                    5/07/2017      336       122.00      0.08      0.90
                                                    1/11/2017      123       137.00      0.13      1.40
                                                   25/12/2017      254        16.00      0.05      0.70
                                                   31/12/2017      121        41.00      0.05      0.70
                                                   18/04/2018      264        46.00      0.03      0.50
                                            AVERAGE                          206.38      0.19      1.64


The catchment condition has also been considered for any correlations to reported data. As
can be seen in the background information some adjacent catchment development was
occurring in the early parts of the testing period (Error! Reference source not found.).
Reviewing the data it can be seen that in general the TSS loadings are higher in the first 6
months of the testing period, with the catchment settling down after this period. There could
be some correlation with the vegetation growth within the system, however an establishment
chronology is not given and could not be assessed. Certainly, the vegetation is well
established by June 2017 (Figure 3).

We note that the Evaluators have not been given any recent photographs of the installation
and the health and robustness of the vegetation in the device approximately 3 years after
commission is unknown.




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