Response to Information Request - Received on 19/04/2012 · OPW11/0335

EP-SMP-06: Maintaining the Bioretention Trenches

6. Frequency/Deadlines                                                                                 1) Plastic litter, accumulated sediment (including silt) and coarse
                                                                                                       particulates: Monthly.
                     ,
                                                                                              "1,      2)Vegetative cover & weeds: Monthly.
                                                                                                       3)Water-logging: Monthly.
7. Responsibilities                                                                                    Site manager.

                                                                                          ~            Landscape contractor.
8. Reporting and                                                                                       1) The accumulation of sediment and coarse particulates reported to the
Review                                                                                            ~.   site manager, and if necessary to senior management;

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                                                                                   \1..                2) The need to restore vegetation or remove weeds reported to the site
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                             ,.                                                    ~-,                 manager, and if necessary to senior management.
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                                                                                       .:iI            3) Evidence of excessive water logging or elongated water holdup reported
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                                                                                                       to the site manager, and if necessary, to senior management
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9. Contingency                                                           ~         )1. :.:.            When loss of control of stormwater flow through the Bioretention Trench
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                                                                                                       occurs:
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                                                                                   .                   1) Inform site manager, and request maintenance support;
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                                                                                                       2) Redirect surface water flow to bypass damaged Bioretention Trench, and
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                                                           cr.                                         direct flow into alternative Bioretention Trench;
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                                                                                                       3) Implemrnt corrective actions when trench has dewatered;
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                                                                                                       4)InvestiQate possible problems with pipework (EP-SMP-07).
10. Corrective actions                                                                                 1) Remove litte/land accumulated sediment;
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                                                                                                       2) Remove silt drapes by rake and spade;
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                                                                                                       3) Remove detritu~ from outlet weir grate;
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                                                       .                                               3) Restore vegetatioq if required by transplanting bare patches;
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                                                                                                       4) Remove weeds marually.                           I
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                                                                                                       5) Replace trench media and re-plant
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EP-SMP-07: Maintaining the pipe infrastructure

1. ObjectiveslTargets                                                                                  Transfer stormwater between treatment units

2. Management Strategy                                                                                 Appropriately sized pipe-work to allow unimpeded flow between treatment
                                                                                                       units.

3. Tasks/Actions                                                                                       1) Inspect flows entering and exiting pipe-work during flow events. Impeded
                                                                                                       flow will cause back-up of water and slow drainage at outlet pipes; and
                                                           :

                             ,
                                                                                                       2) Inspect for wet patches, surface erosion, subsidence on the ground
                                                                                                       surface caused by leaking underground pipe-work.

4. Periormance                                                                                         1) Flow along pipe-work;
Indicators
                                                                                                       2) Evidence of leaking pipe-work
5. Monitoring                                                                                          1) Entry and exit of water along pipe-work; and
                                                                                                       2) Surface expression of water leaking from underground pipes.
6. Frequency/Deadlines                                                                                 1) Flow along pipe-work: During stormwater flow events; and
                                                                                                       2) Evidence of leaking pipe-work: Daily site inspection.
7. Responsibilities                                                                                    Site manager

                                                                                                       Plumbing subcontractor