Site Based Stormwater Managment Plan

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Inspect for the accumulation of an impermeable layer (such as oily or clayey sediment) that
may have formed on the surface of the filter media. A symptom may be that water remains
ponded in the bio-retention basin for more than a few hours after a rain event. Repair minor
accumulations by raking away any mulch on the surface and scarifying the surface of the filter
media between plants. Any leaf litter should be removed to help maintain the surface porosity
of the filter media.

Ensure the perforated pipes are not blocked to prevent filter media and plants from becoming
waterlogged. A small steady clear flow of water may be observed discharging from the
perforated pipe at its connection into the downstream pit some hours after rainfall.

Note that smaller rainfall events after dry weather may be completely absorbed by the filter
media and not result in flow. Sub-soil drainage lines are to be flushed with clean water as
required to remove and blockage.

Sediment should be removed where it has smothered vegetation or caused blockages to the
inlets our outlet systems.

Any holes and or scouring apparent on the filter media will be repaired. Ensure no damage has
occurred to the inlet and outlet systems, if this has occurred repair as required.

5.2.3 Repair of Damage
Any accumulation of an impermeable layer, (such as oily or clayey sediment) that may have
formed on the surface of the filter media will be repaired. A symptom may be that water
remains ponded in the bio-retention basin for more than a few hours after a rain event. Repair
these minor accumulations by raking away any mulch on the surface and scarifying the surface
of the filter media between plants. Any leaf litter should be removed to help maintain the
surface porosity of the filter media.


5.3     Watering
Regular watering of the bio-retention basin vegetation is essential for successful establishment
and healthy growth. The frequency of watering to achieve successful establishment will depend
upon rainfall, maturity of planting stock and the water holding capacity of the soil.

The following watering program should be adequate following the installation of vegetation:

    1. Week 1-2, 3 visits/week

    2. Week 3-6, 2 visits/week

    3. Week 7-12, 1 visit/week

After the first three month period, watering may still be required, particularly during the first
winter (dry period). Irrigation shall be undertaken in consultation with the Landscape Architect.



Bio-Retention Basin Operational Management and Maintenance Guideline