Sediment Control
Sediment control practices are used on building sites to prevent sand, soil, cement and other building materials from reaching waterways. Even a small amount of pollution from a site can cause significant environmental damage by killing aquatic life, silting up streams and blocking stormwater pipes.
Sediment Control usually requires little effort and results in:
- Cleaner waterways and healthier aquatic life
- Reduced clean-up costs to the community
- Improved site conditions
- Improved wet weather working conditions
- Reduced wet weather construction delays
- Reduced losses from material stockpiles
- Fewer mud and dust problems
- Fewer public complaints and less chance of fines
The need for sediment control is influenced by:
- Soil type. Clay soils are more likely to cause environmental harm, while sandy soils are more likely to cause traffic hazards and drainage problems. Exposed subsoils generally cause more problems than exposed topsoils.
- Slope. The steeper and longer the slope, the greater the potential for erosion and sedimentation.
- Extent, nature and duration of the soil disturbance. The greater the disturbance, the greater the risk of erosion and sedimentation.
- Climate and season. Rainfall (intensity and duration) and high winds will influence erosion and sedimentation.
- Size and location of the site. Sediment control on small sites is often harder to implement, especially if the slope is towards the street. Consult your local Council. Large vegetated rural sites may not always require specific controls.
The objectives of sediment control are:
- To divert uncontaminated water away from the site.
- To minimise erosion by minimising site disturbance, stabilising disturbed surfaces and securing material stockpiles.
- To prevent sediment contaminated water leaving the site.
MINIMISING SITE DISTURBANCE
- Prevention is better than cure. Careful design and an efficient construction sequence will minimise disturbance to the site. This will save money and reduce environmental impact.
- Design to avoid excessive cut and fill, unnecessary clearing of vegetation and to preserve existing site drainage patterns. Clear only those areas necessary for building work to occur.
- [See: Choosing a Site]
- Preserve grassed areas and vegetation where possible. This helps filter sediment from stormwater run off before it reaches the drainage system and stops rain turning exposed soil into mud.
- Delay removing vegetation or commencing earthworks until just before building activities start. Avoid building activities that involve soil disturbance during periods of expected heavy or lengthy rainfall.
POST-CONSTRUCTION AND EROSION CONTROL
- Stabilise the site as soon as possible after construction, or while the last trades are finishing, to minimise the potential for ongoing soil erosion.
- Turf lawns are commonly used to stabilise soil but their high water consumption can be an environmental burden. Native ground cover plants do the same thing with considerably lower water use. Avoid replacing native vegetation with turf.
- Mulch (straw or other material) can be used on open garden beds to protect soil and support plant growth. Mulch spread to a depth of 75-100mm minimises soil and water loss and controls weed growth. Mulch may be less suitable on steep sites and in high wind areas.
- Temporary, quick germinating grasses such as rye and oats can be used to stabilise soil until slower growing plants can be established. This method is only effective after the grass seeds have germinated and established a root structure.
- Semi permeable paving can be used to stabilise areas of the site. Avoid excessive use of hard surfaces that prevent stormwater being absorbed.
- Noise can interfere with sleep, rest and conversation and cause fatigue, irritability, headaches and stress. We all need to contain and reduce noise in order to enjoy a healthy life. Thoughtful design and practice can reduce the impact of noise on our lives and improve the quality of our living environment.