Sediment control fences are temporary structures generally installed on demolition and construction as a proven method for trapping soil, sand and other particles. Sedimentary fencing is designed to intercept and retain sediment as it travels across exposed soils whilst simultaneously allowing for drainage. Sediment control measures should be taken on a site prior to any form of soil disturbance begins, down-slope from the construction area. Preventing sand, soil, cement and other potentially hazardous building materials from reaching waterways is paramount as even a small amount of pollution from a site can cause significant environmental damage. Local councils generally have standardised guidelines for sediment control with many requiring a sediment control management plan to be submitted for approval before demolition begins. Failure to adhere to outlined regulations may result in fines.
The extent of sedimentary control measures is determined by several variables:
- Soil type — Clay soils are more likely to cause environmental harm; 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 influence erosion and sedimentation. As rainfall events are likely to intensify under climate change, the extent and severity of erosion and sedimentation will increase and the need to mitigate their impacts will become increasingly important.
- 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.
Intelligent design and an efficient demolition minimises disturbance to the site thus and saving money and reducing environmental impact.