Printed from: https://conservationhandbooks.com/fencing/design-and-siting/factors-in-siting-the-fence/
In some cases the fence must necessarily take a certain exact line. In others, there will be scope for choosing the best route the fence should take.
Fences are easiest to erect on flat or evenly sloping land. More materials are required for all types of fences on undulating land, and strained fences will need extra strainer assemblies, with consequent further expense and effort.
Fences on slopes and uneven ground also tend to be less effective. There may be dips where animals can squeeze under the fence, and places where the ground rises sharply near the fence, which allows animals to jump over.
Avoid fencing above, on or beneath unstable slopes, as sooner or later the fence will be destroyed. As animals and people tend to congregate and walk along the edge of fenced areas, site the fence away from the base or top of the slope, in order to avoid further erosion.
Choose the best soils within the area available, particularly for siting straining posts. Usually avoid rocky and stony areas, where hole digging is difficult. However, in very soft peaty soils, stony deposits or rock outcrops may provide the best place to get a firm anchorage. Avoid permanently or seasonally waterlogged patches, in which posts will not hold firm.
Gullies that become seasonal watercourses are a particular problem, and are not always easy to identify. Look out for any signs of water-flow, including lush grass and other plants of damp ground, water-carved gullies bare of vegetation, and deposits of gravel and silt. Ask local advice. If there is no way of avoiding them, these gullies must be crossed by the fence in such a way that the fence is stock proof in dry periods, but that water and water-borne debris can flow freely down in wet seasons. See page 121 for methods of bridging gullies and constructing water gates.
In areas where snow is likely to be a problem, site fences out of any dips where snow may accumulate. Seek local advice about the places where snow usually drifts, as the weight of snow can break wires and posts.
Also bear in mind that deep or drifted snow can allow animals to walk over fences. Sheep or deer may get into fenced woodlands in remote locations, and then be unable to get out as the snow melts. If possible, site such fences so that there is a natural means of escape, such as a bank or rock outcrop that allows animals to jump out of the exclosure. If there is not a suitable natural feature, it may be necessary to construct a sheep ramp or deer leap out of stone or wood. Fences around small woodlands should always have a gate of some sort, to allow access for management and in case of fire, as well as to let animals out if necessary.
There may be well-established tracks made by wild animals that cross the proposed fence line. Badgers will use the same tracks for many years, and are almost impossible to fence out. They are strong enough to push under tightly strained stock netting, and will soon make a hollowed run through which a lamb can escape. Badgers will also dig under a solid fence to get at their watering or feeding areas.
Either site the fence so that it avoids their tracks, or install badger gates to allow their access, while keeping the fence lamb or rabbit proof.
Deer have traditional routes along which they move, and they may injure themselves by attempting to jump fences in their way. Red deer will attempt to break through any fences that bar their way to traditional feeding grounds.
The line of the fence may be important in its visual effect on the landscape, both in itself, and in any future change it may bring about – the patterns made by the different uses of the enclosures it creates.
The natural boundary line, along a stream, break of slope or soil type is likely to be the most pleasing in appearance. This should also allow for the best economic use of the land, so that the capability of each piece of land, taking into account its soil, aspect and drainage, is fully utilised. For example, an area of land which is partly south facing and well drained, and partly north facing and damp, will not grow a uniform crop. A division along the natural boundary may allow a better land use.
The easiest and most economical line to fence is a straight one, but this does not necessarily blend well in an undulating landscape. Straight fences up and down hillsides are amongst the most obtrusive because they can be seen from long distances, and because they introduce straight lines into landscapes which are often uncultivated or semi-natural. An oblique straight line, such as that taken by a gently sloping track, would possibly blend better. It would also lessen the problem of erosion that follows from clearing vegetation and encouraging animals and people to walk up and down the fence line.
Straight lines for fencing new woodlands can be ‘disguised’ by not planting right up to the fence all along its line. Leave a few areas unplanted, if possible keeping them clear by cutting. The effect can be enhanced by planting a few individual trees or small clumps outside the fence, and protecting them separately. Although the fence line will still be visible as the trees grow, the mature effect will be of semi-natural woodland.