Drainage checks

Good soil structure is important but will not resolve wet areas of the field if the water moving through the topsoil cannot drain away. A well-designed and properly maintained drainage system will improve the trafficability of soils, reduce the delay time for re-entry to fields after rainfall, and increase the growing season. A drainage system may consist of a combination of land improvements such as ditches and other watercourses, subsurface drainpipes and pumping systems.

It is important that you check and maintain drainage systems properly to reduce problems with waterlogging, excessive runoff and sediment transfer both on farm and down-stream.

  • In the wetter winter months, investigate wet patches and areas of the field with standing water
  • Check farm plans for existing field drainage
  • Maintain existing drainage, including outlets and drainage channels
  • Ensure field drain outfalls are not buried in silt or continuously submerged (Ideally outfall should be 150mm above normal winter water level)
  • Regularly check field drain outlets especially in late winter and early spring when they should be running freely (following rainfall of at least 5mm in one day)
  • Clear any blocked or slow running drain outfalls
  • Look for signs of reddish-orange slime in outlet pipes which can block the drainage systems and needs to be flushed out by jetting (there is no permanent remedy for this problem)
  • Where the soil is relatively stone free and clay content is greater than 25 -30%, mole drains should be created across existing permeable drains every 5-10 years.