Catchment Sensitive Farming: Practical Tips

Practical Tip: Fencing

The exact siting and choice of fencing should take into account:-

  • The need to permit farm operations;
  • The risk of flooding and the accumulation of debris on the fence, leading to flood risk management problems downstream and possible damage to fence;
  • The risk of river channel movement and subsequent loss of fence to the river;
  • The desirability of maintaining restricted grazing of riparian areas to encourage habitat diversity and flora and fauna dependent on vegetation management and light poaching.

The easiest and most economical line to fence is a straight one, but this does not necessarily blend well into the landscape.  The exact location of a fenceline may have a significant visual impact on the landscape within the floodplain.  Its visual impact can be reduced to some extent by following the natural boundary line, along a stream or river bank.

New fencing should avoid sites of archaeological or historic importance.

Types of Fencing

Conventional strained fencing

This type of fencing is the most commonly used, because of its versatility and ease of erection.  Straining posts and stakes or droppers are located at intervals according to the type of fencing. e.g. high tensile fencing.

Wires of various thicknesses and strengths can be chosen to suit the situation and use, and the fence can be made of single wires or netting, or a combination of both.

Permanent electric fencing

This is a lightweight strained fence that maybe used when problems associated with flooding and debris presents a risk to a conventional fence.

Post and wire fencing

All types of fencing must be erected in accordance with BS 1722 Fences. All softwood timber must be fully peeled and tanalised or treated with an approved preservative.  Durable hardwood, such as oak or sweet chestnut, may be used and does not require treatment with preservatives. Timber sizes quoted are minimum requirements.

Wire fencing must be at least 1.05 m high. Use galvanised 4 mm mild steel plain or 2.5 mm barbed wire, or equivalent as stated in BS 4102 Steel wire, wire ropes and link chains. Straining posts must be at least 125 mm top diameter, 2.1 m long and at spacing not exceeding 150 m. Struts must be 65 mm top diameter, 2.1 m long and notched into the straining post. Intermediate posts must be 65 mm top diameter, 1.7 m long and at spacing not exceeding 3.5 m. Barbed wire must not be used where fencing runs alongside access routes, unless this is unavoidable.

Permanent Electric Fencing

Wire specifications and the number depend upon the type of livestock that are to be excluded.

Wire fencing should be at least 1050mm high and constructed using a minimum of 4 mild steel or high tensile plain wires to comply with BS 4102.  Details on the required number of wires and spacing is provided below.

Straining posts should be at least 150mm top diameter, 2150mm long and spaced according to the type of wire used.  Struts should be at least 80mm top diameter, 2100mm long and notched into straining posts. Intermediate posts should be not less than 63mm top diameter, 1700mm long and spaced according to the type of wire used.

A mains-operated energiser should be installed in accordance with the Institute of Electrical Engineers IEEE Regulations and comply with BS EN 61011 1993.

Where no mains electricity exists, an electric fence may be powered by solar energy.  Solar energisers must also comply with BS EN 61011.  The electric fence and solar energisers should be installed and maintained as to manufacturer’s specifications.

Once erected, electric fences should be routinely inspected for any sagging wires, earthing via vegetation or debris or any other problems that may reduce its effectiveness.  When livestock are initially introduced fences should be inspected daily for the first week and thereafter inspections should be at least weekly.

On uneven ground, additional support posts will be needed to ensure wires are kept at a uniform height.

Post and Wire spacings

(as recommended by Gallagher Power Fence Ltd)

For dairy and beef cattle

For a 2 wire fence post intervals should be at 15-18 metres and wire heights should be at 60 cm and 90 cm above ground level.

For a 3 wire fence, post intervals should be at 10 -15 metres and wire heights should be at 15cm, 75 cm and 105 cm above ground level.

For sheep and goats

For a 5 wire fence, post spacing should be at 10 metre intervals and wire heights should be at 15 cm, 30 cm, 45, 65 and 90 cm above ground level.

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