RFI - ATTACHMENT A - SBSMP - Rev 2

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It is also the time when high sediment loads may impact on plant growth and infiltration rates.
For this reason, the bio-retention systems are to be initially turfed. Vegetation can be
introduced when construction has been completed on an appropriate percentage of the lots
draining to each bio-retention system.

Inflow systems and overflow systems require careful monitoring, as these can be prone to scour
and litter build up. Debris can block inlets or outlets and can be unsightly, particularly in high
visibility areas. Inspection and removal of debris should be done regularly, and debris should be
removed whenever it is observed on a site.


5.2     Inspections
5.2.1 General
The bio-retention basins treat stormwater runoff through the principles of sedimentation,
filtration and percolation. These devices do not incorporate the use of screens and require
minimal maintenance during their operation. However, the systems are subject to deposition of
sediment that is filtered through the media.

Routine inspections shall be undertaken on the bio-retention basins after every significant
rainfall event (30mm of rainfall in a 24 hour period) or on a three (3) monthly basis within the
first twelve (12) months and on a six (6) monthly basis thereafter. The requirements of the
inspection for the bio-retention basin shall include the following:

    1. Check for build up of sediment at pipe inlet structures;

    2. Check for sediment within sub-soil drainage lines;

    3. Check all concrete structures for damage and deterioration;

    4. Check for the build up of vegetation matter on the bed surface and removal of
       vegetation matter to ensure minimal blockage to media;

    5. Check achieved flow rate through the media is maintained in accordance with the design
       requirements and anticipated compaction;

    6. Check inflow systems, outlets and the under drainage pipe elements to identify and
       remove any blockages such as litter build up.

5.2.2 Filter Media
The filter media will be inspected for sediment deposition of the bed of the bio-retention
basins and removed as required.




Bio-Retention Basin Operational Management and Maintenance Guideline