Sediment controlSediment 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:
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. SEDIMENT CONTROL DEVICESGeotextile fabric sediment fences  These are generally the most efficient barrier for building sites. Constructed from geotextile fabric attached to posts, these fences trap sediment but allow water through. On small frontage sites with limited access, use steel posts and wire tied fences that can be readily unhooked for unloading of materials. Straw bale sediment fences  Secure straw bales with two stakes per bale. Butt the bales close together and set them into the ground as shown, to prevent water from flowing under or around them. Straw bales do not filter sediment from stormwater as quickly as geotextile fabric and may not be the best solution on sites with high volumes of runoff. Re-use bales as mulch to stabilise soil after construction. POST-CONSTRUCTION AND EROSION CONTROLStabilise 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. [See: Stormwater] Biodegradable erosion control mats are useful when revegetating steep slopes. Integrate landscaping strategy with sediment control. For example, diversion channels and trenches that filter sediment can be used with rubble in the base to create a deep root planting opportunity. Source: http://www.greenhouse.gov.au/yourhome/technical/fs52.htm |