Earthworks can lead to adverse environmental effects, especially the risk of erosion and sedimentation. It is well documented that earthworks are a significant contributor to sedimentation from all forestry operations, including harvesting.
Three FOA publications describe good environmental practice – this Manual and the accompanying Operators Guide, and the Forest Practice Guides. Chapter 2, Regulations, Consents and Approvals, discusses the regulatory requirements that provide rules around forestry and its potential adverse environmental effects. These should be referenced when planning or managing earthworks.
The following are important practices:
- Earthworks should be planned, designed, supervised and constructed by appropriately trained personnel, employing engineering expertise where prudent to do so
- Comply with all appropriate regulatory requirements, consent conditions and other authorities that relate to the particular earthworks activity
- Ensure important environmental values and sensitive areas are identified, and appropriate mitigation measures taken to protect these before an operation starts
- Ensure all construction personnel are aware of and understand the environmental issues, and the required mitigation measures
- Ensure equipment operation or earthworks activity operates behind a buffer zone, and does not migrate outside the intended zone into sensitive or protected areas such as rivers, wetlands, or archaeological sites
- Establish and maintain temporary drainage and sediment control during and after the earthworks construction period, until the site has stabilised
- Ensure erosion and sediment control structures are located and sized to the job
- Stabilise the site quickly; this may require vegetative and non-vegetative methods
- Construct stable earthworks fills, and avoid creation of unstable cut slopes
- Ensure handling of fuels, oils, construction material, waste and possible weed seed transfer is managed to minimise the risk of contamination of the site
- Avoid construction in wet conditions.