Erosion and sediment control
Soil erosion from building, development and construction sites is a major source of stormwater pollution.
When it enters our waterways, sediment (such as soil, sand, silt, mud) and litter washed from urban areas can cause short and long term environmental problems.
Erosion control measures are the first line of defence in preventing onsite and offsite erosion, and the preferred option for erosion management on site. It is the cheapest control measure and achieves the best outcomes.
Erosion control aims to prevent or reduce soil erosion caused by rainsplash and sheet erosion.
The best form of erosion control is to maintain maximum plant cover on the soil surface, and to minimise the "footprint" of soil disturbance. If the removal of plant cover occurs and the soils are disturbed, site managers must adopt other erosion control measures. These may include:
- bonded fibre matrix
- compost blankets
- erosion control blankets
- soil binders and surface stabilisers
- surface roughening.
- specific control measures selected will depend on site conditions.
Entry and exit points at work sites, where heavy vehicles use is frequent, are focal points for erosion. Gravelling these high use areas is an effective erosion control measure.
Effective erosion control also means effective drainage control measures.
Site managers should:
- divert up-slope stormwater runoff to flow around soil disturbances and discharge off site
- divide the work site into manageable drainage areas, with flow paths stabilised and managed
- Ensure dirty water is to be kept on site and disposed of appropriately (e.g. evaporation, flocculation and discharge of clean water)
- minimise flow velocity and soil erosion within drainage channels and chutes (e.g. regular spacing of check dams etc.).
Sediment control measures are the second line of defence in preventing onsite and offsite erosion effects. They aim to trap and retain sediment, both fine and large, that has eroded from the site.
Typical sediment control measures include:
- buffer zones
- construction exits
- sediment fences
- sediment basins/weirs
- grass filter traps
- rock filter traps
- compost/mulch berms
- drop inlet protection
- Specific control measures selected will depend on site conditions.
Drainage control measures applicable to sediment control include:
- diverting up-slope stormwater runoff away from excavations.
- diverting clean water around sediment traps, reducing total volume of water to be trapped and treated, reducing the size of the sediment control measure.
Under the Environmental Protection Act 1994, all persons who cause land disturbance have a legal responsibility to minimise or prevent environmental harm.
Property developers and other development industry members, such as consultants and contractors, must further comply with the requirements of the Planning Act 2016. Development conditions on construction approvals require the implementation and maintenance of adequate erosion and sediment control measures.
If you choose not to implement appropriate erosion and sediment control measures, it could cost you an on-the-spot fine of $2,000 to $5,000.
Prosecution and court penalties for major development and environmental offences may exceed one million dollars.