4.3 Containing Path Use
Movement off the line of a newly constructed, or defined path can cause further damage and erosion of fragile revegetating areas. It is essential to prevent this with careful landscaping and placement of ‘natural’ obstructions, as part of the site restoration.
Incorporating "blocking" features, or obstacles, in the site restoration serves to channel and contain use on the path and discourage walkers from leaving it. Before considering preventative work it is necessary to identify why and where users will be tempted to move off the path line. This may include:
- poorly constructed or rough path surface
- steep or difficult sections of path
- easier walking ground adjacent to a hardened path
- short zigzags on a slope where walkers can descend an easy fall line
- old path lines appearing as alternative or more direct routes
- poorly positioned drainage features channelling use off the path
- steep path crossfalls "pushing" use off the path edge
- short-cuts or desire lines to a particular destination
Bill of Quantities (example)
Use large boulders and turfs with landscaped mounds to prevent use of path sides, alternative paths or desire lines. Obstacles and mounds must be large enough to contain path use but appear natural and blend with surrounding area.
The following methods developed to channel and contain path use can be used together or individually, depending on the nature of the site and the problem.
- strategic positioning of large blocking boulders
- turf and spoil bunds, mounds and bankings
- turf and stone placement over alternative paths
- ground roughening of open path sides
The appropriate choice will depend to a large extent on the materials available.
Any of the following can be used to contain path use:
- Mixed size stones
These materials and the general principles for using them are detailed in Materials and Use.
Whichever method is used to prevent movement off the path, it should not be perceived by users as a deliberately placed obstacle. Rather than being a physical barrier the obstacles should create an impression of difficult ground. To be effective these need to be carefully positioned where problems may occur. The most common places are at:
- changes in the type or condition of path surface
- points of access off the path onto easier ground
- path corners or changes in alignment
- changes in gradient, particularly the top of steep downhill sections
- points where braids or old paths leave, or are obvious from, the pathline
- drainage features on corners or bends, particularly waterbars
- lower path sides on traversing paths
- the point where destinations become obvious or visible e.g. car parks, view points, landscape features
For strategic positioning it should be remembered that the path user's visual assessment of a better or alternative route will be different when ascending and descending.
When blocking ascending off-path use, the obstacle needs to be at the path edge as the walker's view will be limited to the slope immediately above.
A descending walker will be looking further ahead, and over a wider area. More than one feature will be required, positioned randomly, but to obstruct the view of an alternative line and to give the appearance of rough ground.
On zigzag paths the best position is immediately below the lower path edge particularly at the bends.
Large boulders should be used, at the point where walkers may be tempted off the path by an apparently better route. The best positioned blocking boulders will not be obvious to path users. Turfs transplanted around them will help to achieve this.
On alternative paths or wide path sides more than one boulder may be required, and care with positioning is needed. Blocking boulders, and their placement, must mimic and look as natural as any others in the surrounding landscape.
Bunds, Mounds and Bankings
Along with occasional boulders, these are the ideal method of containing path use, so long as their appearance blends with surrounding area. They may be the only option available in situations where boulders are in short supply or do not fit the surrounding area. Using spoil and turfs they can create longer obstacles, either along the path edge or at an angle to the path, and, as low mounds, across alternative paths or braids. As well as blocking off-path use they encourage or divert use onto a particular alignment, particularly on zigzag paths.
Carefully positioned raised bunds or banks along the path edge, is particularly useful in preventing movement off the path onto revegetating sides. They also serve to reduce the visual impact of a hard path edge or the path alignment in the landscape.
Where there is no spoil or turf available, mounds and hollows can be carefully created. Turf is removed over an area, and a hollow dug; the spoil is used to create a mound; and both the hollow and mound re-turfed. This is particularly useful to prevent use of easier, softer ground adjacent to a hard path.
Mounds used as obstacles must be substantial enough for the purpose, and rough enough to deter use over them. However, care is needed to avoid creating unnaturally high features.
As with boulders, the emphasis is on their natural appearance, avoiding uniform shapes or positioning. Where used for banking alongside the path edge, care is needed to avoid long unnatural looking mounds of regular width.
Large turfs can be used, with boulders if appropriate, at the path edges to prevent movement off the path, and to disguise and block the line of braids and desire lines. The aim is to ‘roughen’ the appearance and care should be taken not to create a better walking option than the path.
This method is suitable on wide open areas adjacent to the path, where large boulders or turfed mounds would not be appropriate. The aim is to roughen the ground enough for it to appear unattractive to walk on. On eroded ground this can be achieved with mixed size, weathered stone scatter over the surface. Small, low mounds and hollows may also be appropriate. These can also be used effectively to create an uneven grassed area. Mixed height turfing, combined with weathered medium size stone can also achieve the desired effect. Particular care is needed with this method to avoid a contrived unnatural patchwork of material.
Key points to watch:
- correct positioning of the feature - further erosion will occur if walkers continue to deviate from the path
- avoid periods of dry weather when turfing
The following maintenance may be required:
- replace worn or dead turfs
- reset loose boulders or stone
- move, or extend features to effective positions
- the features used must fit in with the surrounding landscape; a natural look is essential
HEALTH AND SAFETY HAZARDS
- use safe lifting techniques when manoeuvring large boulders
- when moving large boulders divert the public and warn other workers on the path below
- step back from the work as you are doing it - view it from the path and at a distance to check for the correct position and merging with surroundings