Specific Tasks

Decanting earth bund and diversion bund used to treat runoff during construction of a farm track.

When constructing tracks, consider the size of the catchment to avoid watertables cutting down and eroding, especially in loess or hill terrain. This is a fairly common problem – tracks up slopes need to have frequent cut-off drains, so that the volume, velocity and power of water accumulating is always minimised.

Water accumulated in a cut off should be discharged to land so it won’t erode the receiving surfaces. Use energy dissipating structures, like rock-lined channels, or discharge into existing waterways. Consider the effect of additional peak flows from new areas will have on existing channels or waterways. Higher peak flows will carry more energy and have more scour and erosion potential, so there is greater risk of those waterways becoming flooded, eroding their beds and creating flood risks downstream.

All the normal ESC tools apply, such as:

• Minimising the exposed area
• Keeping catchments small to minimise the volume and power of dirty water
• Minimising vegetation disturbance
• Protecting waterways
• Diverting clean water
• Covering and stabilising exposed soils.

Ensure that you comply with Permitted Activity and resource consent requirements, including for the crossing of waterways.