Do all stormwater filters have the same maintenance frequencies?

10 March 2015

The introduction of Water Sensitive Urban Design (WSUD) has been brought about by a realisation of the significant impact a development can have on its surrounding environment and water quality is one of the most important of these impacts, as pollutant concentrations are directly proportional to the destabilisation of the surrounding ecosystem.

Stormwater filters, like all Stormwater Quality Improvement Devices (SQID’s), require a suitable maintenance / monitoring program to continually operate at optimal performance. Accurate maintenance frequencies are therefore identified as a strong driver for long term water quality, hence many Local Government Authorities (LGA’s) within Australia have now made it mandatory for stormwater filter systems to be maintained using a feasible approach.

The variability of maintenance frequencies is quiet excessive and depends on a multitude of site specific catchment conditions. These include;

  • Geographical location
  • Land usage
  • Pollutant load concentrations and stream flow
  • Climate change
  • Type and quantity of pollutants
  • Frequency and extent of storm activity
  • Effective maintenance of upstream pre-treatment devices

As part of a treatment train, stormwater filters have the ability to remove fine particles, soluble heavy metals, oils and total nutrients. Generally contained within a precast manhole / vault allows the site owners to optimise land use.

A lack of proper maintenance of a stormwater treatment device can lead to:

  • Stormwater structures or storage facilities becoming clogged with debris or sediment, leading to reduced flow or storage capacity, which in turn may result in flooding of the site and damage to Stormwater assets and nearby infrastructure
  • A failure to comply with local authority regulations relating to stormwater quality standards, which may result in penalties for the site’s owners or property managers
  • The likelihood of costly repairs, increased ongoing maintenance costs and the potential of damage to other infrastructure or drainage assets

Areas with the greatest potential for high pollutant loading include industrial areas and heavily travelled roads. At present, maintenance of Stormwater filters (in particular the StormFilter) generally includes periodic inspections particularly after major rainfall events whereby records of the depth of sediment accumulation and media condition is reordered. The current estimated maintenance frequency is every 12 – 18 months.

A properly functioning system will remove solids from water by trapping these particulates within the porous structure of the media. The flow through the system will naturally decrease as more and more solids are trapped. Eventually the flow through a system will be low enough to require replacement of the cartridges. Sediment is removed from upstream trapping devices to prevent material from being re-suspended and discharged to the system.

If you have a Stormwater device that needs maintenance, please visit our website to send through an enquiry or call us on 1300 345 722.


Fotos Melaisis

Project Manager – Stormwater360