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

EP-SMP-02: Maintaining the underground                                                                             Rainwater Tanks associated with the ornamental
garden irrigation scheme                                                                                                                                    "   .




1.0bjectiveslTargets                                                                         To maintain the continued operation of the two 100 m3 underground
                                                                                             Rainwater Tanks for rainwater recycling.

2. Management Strategy                                                                       1) Efficient and cost effective capture of rainwater;
                                                                                             2)Water quality suitable for irrigation use.
3. Tasks/Actions                                                                             Routine checks on structural integrity

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                                                                                             1) Check hard surfaces used for collecting rainwater for pollutants (oil or
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                                                                             .".             petrol spills, dirt, litter);

                                                                                             2) Check the screen for litter and structural integrity; and
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                                                                                             3) Check the rainwater tank for cracks, cement rot, or leaks. Check inside
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                                                                                             the tank for accumulated sediment and nuisance biota.
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                                                                                             Routine checks on water quality
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                                                                                             4)Water quality tests once a month for each 100 m3 tank.
4. Performance                                                                               1) Costs of maintaining the rainwater capture system are kept to a
Indicators                                                                                   minimum;
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                                                                                             2)Water quality parameters should conform the ANZECC 2000 guidelines
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                                                                                             for secondary contact.

5. Monitoring                                                                                1)Structural Integrity: contributing surfaces are free of pollutants (litter,
                                                                                             petrochemicals, sediment). The tank structure needs to be checked for
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                                                                                             visible cracks, rust, leaks, blockages, and sediment accumulation.
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                                                                                             2)Water Quality parameters: microbial, Iiluisance organisms, aesthetics,
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                                                                                             clarity and cOl ur, toxic chemicals, oils and debris.
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                        r.:._-                                                               Microbial Guideline values: The median value in fresh and marine waters
                                                                                             should not exceed 1000 faecal coliform    6rganisms/100 mL or 230
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                                                                                             enterococci organisms/100 mL.
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                                 "’                                                          Nuisance organisms: Phytoplankton scums, filamentous algal mats, fungus,
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                                 IJ    r4                                                    leeches should not be   resent. Direct contact should be discouraged if
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                                                                                             algal levels of 15 000-20 000 cells/mL are present, depending on the algal
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                           ;’!.                                                    iIiJi     avoided.

                                                                                             The pH of the water should be within the range 5.0-9.0.

                                                                                             Toxic chemicals Waters containing chemicals that are either toxic or
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                                                                                             irritating to the skin or mucous membranes are unsuitable. Toxic
                                 ~         ,                                                 substances should not exceed values in tables 5.2.3 and 5.2.4 in the
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                                                                                             ANZECC 2000 guidelines.

                                                                                             Surface films Oil and petrochemicals should not be noticeable as a visible
                                                                                             film on the water nor should they be detectable by odour.

6. Frequency/Deadlines                                                                       1) Contributing Catchment Condition: daily.
                                                                                             2) Screen: Monthly.

                                                                                             3) Structural Integrity: once a year.
                                                                                             4)Water Quality: once a month.
7. Responsibilities                                                                          Site Manager

                                                                                             Plumbing sub-contactor qualified to work in enclosed spaces.
8. Reporting and                                                                             Annual record of the rainwater system and water quality performance, and
Review                                                                                       exception reporting of failure and replacement, supplied to senior
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                                                                                             management for review.