Managing stormwater on building sites

The property owner and builder are both responsible for controlling soil erosion and preventing sediment from being washed into stormwater drains.

Soil erosion on building sites can be a major source of sediment pollution in our waterways. A single building site can lose four truckloads of soil in one storm. When washed into stormwater drains, this sediment is eventually deposited in creeks, rivers and lakes. The cumulative effect of polluted runoff from building sites can have a dramatic impact on water quality.

Under Section 120 of the Protection of the Environment Operations Act 1997, heavy fines may be imposed if a person allows soil, earth, mud, clay, concrete washings or similar material to be washed, or likely to be washed, into stormwater drains. On-the-spot fines of $15,000 for individuals and $30,000 for corporations can be issued for first offences. Further fines of $22,500 for individuals and $45,000 for corporations can be issued for repeat offences.

Pollution prevention measures

All building sites should adopt the following measures to prevent pollution:

  • restrict vehicle access to one stable entry and exit point
  • preserve grassed areas and retain the maximum cover of natural vegetation by minimising the amount of land disturbed by shaping. Mulch or revegetate disturbed areas as soon as possible 
  • ensure that stockpiles of sand, gravel, soil and similar materials are located so that material:
    • does not spill onto the road or pavement
    • is not placed in drainage lines, depressions or watercourses
    • cannot be washed into roadways, drainage lines, depressions or watercourses

Further steps include:

  • removing accidental spills of soil or other materials onto the roadway or gutter prior to the completion of the day's work
  • not allowing excess materials and water from cleaning tools and equipment to be washed down stormwater drains
  • locating houses and buildings on the site so that cut-and-fill operations are minimised
  • ensuring access driveways are no steeper than necessary
  • minimising on-site vehicle activity during wet weather or when the site is muddy.

To assist you with managing stormwater waste from your building site, Council has a waste management plan template that may be used in support of a development application.

Controlling erosion

Management strategies to control site erosion and the water quality of runoff vary and are determined by the following factors:

  • soil type
  • slope of the site
  • site erosion hazard rating
  • surface rock
  • extent and duration of site disturbance
  • proximity of watercourses and drainage lines
  • sensitivity of receiving waters.

When the erosion hazard rating for the site is high or moderate, we will likely require a soil erosion and sediment control plan. Guidelines can be obtained from the Department of Land and Water Conservation.

If the site has a low erosion hazard rating, general protection measures are required. These include appropriately placed and maintained sediment controls such as sediment traps and barriers, and silt fences and straw bales below fill batters or highly disturbed areas.

View our Erosion and Sediment Control brochure for more information.

The effect on the environment

There are many environmental problems directly associated with pollution from building sites.

  • when water carrying pollutants like soil, soil nutrients and concrete residues, runs off building sites and enters stormwater drains, there is a subsequent pollution of natural water courses
  • changes to natural land surfaces and drainage patterns that accompany urban development can result in natural watercourses becoming turbid, silted, littered and undesirably enriched with nutrients. This nutrient-rich water often develops algal blooms
  • when turbid water restricts sunlight filtration, photosynthesis is reduced and productivity of the aquatic ecosystem suffers.
  • watercourses are subject to increased flooding, particularly where catchments have been cleared of vegetation. Subsequent flooding and erosion contribute to siltation problems downstream.
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