To further assist the drainage of your land, a mole drainage system can be installed to guide excess water into your open drains or into subsurface drains using the fall of the land.
Mole drainage, on the right soil type and done properly will help reduce waterlogging problems. Mole drainage is widely used in New Zealand, England and Europe on heavy soils to improve productivety of pastures and crops.
Mole drains are unlined channels formed in the clay subsoil with a ripper leg with a cylindrical foot, with an expander which helps compact the channel wall. The floating beam mole plough is the preferred plough design as it evens out irregularities in the slope of the drain caused by local surface variations.
Mole drains over sub-surface drainage Cross section of mole plough effect in soil
Suitability for mole drainage is dependant on having the right soil type. Clay soils are ideally suited, while sandier soils will not hold the mole drains for any period of time. The mole drains are formed by pulling a ripper leg with an expander through the soil. The ripper leg breaks the soil while the expander forms a channel (Figure 2). The cracks in the soil form little waterways to the channel in the ground. Mole drains are installed between 2 and 2.5 metres apart. The mole drains can be installed either in combination with sub-surface drainage, or with open drains.
In undulating country the sub-surface drains are often in the leads of the lower areas of the land. The mole drains are put in across the sub-surface drains cutting through the gravel. Water will drain down the mole drains and into the sub-surface drains.
Alternatively mole drains can be used in conjunction with open drains. The mole drains start in the open drain and follow the slope of the land.
The mole plough is being pulled by a 215 horsepower, articulated John Deere 8450 on dual wheels front and back to optimize traction. The duals prevent wheel slipmarks which could damage your pasture.
Mole drainage is the most cost effective way of draining your paddocks.
The ideal time for installing mole drains would be spring to early summer.
Please click on photos to enlarge.
For additional, more detailed information please see the Ag-notes AG0949 of the Department of Primary industries, Victoria.
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