1.4. Path Survey
Introduction
Path Surveys gather physical information about the path from detailed on-site inspection and measurement. They form the backbone of a good Path Assessment. The results provide the basis for funding strategies and pathwork implementation.
A number of different methods of survey have been used in Scotland over the past fifteen years. These have developed in isolation, resulting in no continuity or standard of information being gathered. It has therefore been difficult to obtain an overall picture of the condition of Scottish upland paths.
The formation of the Path Industry Skills Group (PISG), brought about an agreement to standardise surveys. Two methods, predominantly used in Scotland, are used by UPAG members.
- CONDITION SURVEYS - as used for the Cairngorm Path Survey and the Loch Lomond and Trossachs Footpath Condition Survey. Collects data about the existing condition and indicates where problem lengths will require work, and a specification survey. The data should provide a ‘base line’ for repeat monitoring.
- SPECIFICATION SURVEYS - as used for the Wester Ross Footpath Survey, Loch Lomond and Trossachs Survey, Cairngorm Survey for HIE, and various individual path surveys for SNH. Essentially a ‘quantity survey’, which provides further detail on problem sections, assesses the problems and prescribes and quantifies the work required to repair the path.
Condition surveys are usually carried out over a wide area to assess paths and decide which ones to manage first. The information is useful for up to 5 years and can be used to monitor changes in conditions. Specification surveys are usually carried out on sites where work will take place in the next 1-3 years. They are more detailed, take longer to survey and are used to specify the work required. Ideally the condition survey will identify where specification surveys are needed - but where damage is evident and urgent action needed, both types of information are gathered on one survey visit.
There are several factors common to both survey methods.
Surveyor and Timing
Surveys are normally carried out by one person who may be an experienced path surveyor, a path management specialist, or a competent pathworker with at least two years experience. The more familiar the surveyor is with the site the better. All surveyors should be trained and familiar with the survey method and reporting.
Surveys should be undertaken on as wet a day as practicable, or after spells of wet weather, so that path and drainage problems are seen at their worst. However high winds and heavy rain slow the survey down; still days are always preferable. Winter should be avoided for obvious reasons; increased likelihood of snow on the path, and the difficulties of recording on survey sheets with cold, wet hands.
On average it takes one day to cover 2 kilometres of path for a specification survey. However, path condition, access time and weather can influence this dramatically. Additional days are required for writing up survey sheets, for data input, and report preparation.
Path Identification and Sectioning
Paths to be surveyed will be marked on a map base and identified with a numbering system. Grid references for the map based start and finish points will be required for the field survey sheets, and reporting.
Surveys usually start at the base of the route and work uphill. The start point should be the most obvious point of access, i.e. where the path leaves the road, a main path or track, or at its junction with another path in the network being surveyed. For ‘stand alone’ specification surveys it may be at the position where damage starts on the path.
During the survey each path is divided into sections. Section start and end points are best made at places with distinct changes in physical condition of the path or terrain. These will become apparent as the surveyor progresses along the path. Change points may include:
- path type, character or direction
- path gradient
- path surface or width
- nature of erosion
- vegetation type
- path junctions
- notable physical features
Section changes should be at measurable points which are clearly identifiable and permanent for further monitoring and specification surveys. Section lengths are progressively numbered, and uniquely referenced to the path identifier number, before marking on a map base and grid referenced. Any additional spurs or loops attached to the path should be annexed to the main path, with additional numbering. Depending on their length, and level of use, a separate path identifier and sectioning may be required.
Section lengths are variable, and not pre-set. It may be useful for a path manager to define a minimum or maximum length for ease of data handling and analysis, future monitoring or work programmes. For example, a specification survey that will be used to let contract work may have a larger number of shorter sections, to help identify separate elements of future work. Sections can be subdivided, either during or after the specification survey, mainly where obvious changes in the pathwork alignment, design and technique occur.
The survey sheets do not have any restriction on the number of sections or length of path recorded on one sheet - the scale is elastic. Some sections may be complex and require a lot of detail to be recorded; maybe covering only 50 metres of a section on one sheet. Others may be straight forward with very little variation in condition, with up to 300 metres on one sheet.
Equipment required
Basic equipment required for both survey methods includes:
- STANDARD SURVEY SHEETS - preferably prepared on waterproof paper
- MAP AND COMPASS - for geographical location and defining path direction
- CLINOMETER - for measuring path and slope gradients
- TAPE MEASURE - for path or damage widths or short treatment lengths
- CANE OR SIMILAR PROBE - for investigating waterlogged ground, peat depth etc.
- CAMERA - for fixed point photographs of typical condition, and erosion problems
- GLOBAL POSITIONING SYSTEM
- MEASURING WHEEL
- DATA CAPTURE DEVICE - hand held computer with specifically designed software for logging survey data; may be used on-site for direct data input or for rapid data input after each day’s survey
CONDITION SURVEY
Function
The purpose of a condition survey is to record the present condition of the path, in order to inform management decisions. The resulting data gives invaluable indications as to where priorities for work lie. It may prescribe where work is required but does not provide a detailed specification. The survey method can be repeated for future monitoring.
Condition survey results are generally used by path managers, landowners and funders to:
- identify the worst sections of erosion and potential problem routes and sections
- define and prioritise where pathwork and specification surveys are required
- integrate with the management plan for the surveyed area
- provide baseline detail for future condition monitoring and the measurement of any change
- draw comparisons with other paths and sites to enable informed decisions to be made for prioritising resources
Method
As this method is used infrequently for site work and practical pathwork, it is not described in full in this manual. Instead an example is given of the survey. Full training in recording site data and analysing and interpreting the results is required to make best use of the information in condition surveys, and is outwith the scope of this manual.
Survey measurements and notes from the first four sections of the Cobbler path survey. Loch Lomond and Trossachs Upland Footpath Condition Survey, 1998. The Footpath Trust, for Scottish Natural Heritage. Click to enlarge the image.
Example
An extensive, area based, condition survey was carried out in the Loch Lomond and Trossachs. The survey was carried out for Scottish Natural Heritage, by The Footpath Trust, and the opportunity was taken to revise the survey methods and create a database to handle the mass of survey data.
Data Collected
Four types of data are collected for a condition survey:
1. DESCRIPTION
- date, and weather before and during survey
- path and section number and reason for change of section
- map location and grid reference, for start/end of each section
- section length and cumulative path length
- type of path and surface
- surrounding vegetation type and cover
2. MEASURES
- number of ‘main’ paths and number of braids
- bare width range - minimum and maximum width of bare unvegetated ground across the path
- trample width range - minimum and maximum width of trampled ground across the path
- gully depth range - minimum and maximum depth of eroded gullying or soil loss on the path
- long gradient and cross-fall - average gradient along the path; average gradient up the fall-line
3. INDICES
Assessment of non-measurable factors uses indices on a scale of 1 to 5, where 1 = the worst or most active, and 5 = the best or least active. The factors are:
- Roughness - the condition of the surface, how hard or easy it is to walk on
- Drainage - the effects of water on the path, standing water, seepage and water flow
- Erosion - the present rate of damage to the path line
- Condition - the overall condition of the path
- Dynamism - the predicted rate of change to the path condition
4. PRESCRIPTION
The final set of data recorded includes additional information relating to path management. These may be comments on work required, ancillary structures, access, availability of materials etc.
Photos illustrate the nature of measured or non-measurable indicators, particularly where dynamism is active, or specific problems which are difficult to quantify. Photos are numbered and positions recorded, with the direction taken along, or across the path.
RESULTS
Using specially designed software, the data can be analysed to provide a wide variety of information, from simple summaries to elaborate cross-tabulations, for each section. These may compare dynamism to gradient; drainage to roughness etc.; presented in a number of formats including tables, graphs and charts; with percentages, averages and total numbers. They can be a useful management tool, enabling data comparison for networks of paths, and throughout different regions.
The analysis results should then be integrated with the path assessment, to help formulate a management plan for the path.
Extract from the Cobbler path survey data report, as entered on the survey database. Generated using MS Access database. Loch Lomond and Trossachs Upland Footpath Condition Survey, 1998. The Footpath Trust, for Scottish Natural Heritage. Click to enlarge the image.
SPECIFICATION SURVEY
Function
The main purpose is to provide detail of the work required to restore the path to a good condition. The detail includes the number and location of structures and features required, as well as estimated work days to carry out the work.
It provides path managers and land agents with work quantities, timings and costings, and can be used to draw up specifications and bills of quantity for letting contracts. It is also intended as a working document for use by the pathworker to locate the work required on site. It is an essential part of any contract for pathwork.
Method
The surveyor details information about the present path condition and records cumulative measurements. The need for treatment, and the appropriate techniques are considered, prescribed, detailed and measured, along the equivalent path length. The path condition and potential treatment is depicted on the survey sheet using a standard set of symbols (see Glossary of Symbols). Obvious landscape features are also depicted, to help locate the position along the path.
The surveyor also lists and quantifies each element of pathwork, assesses the site conditions and calculates the number of workdays required. As the conditions affecting construction time vary from site to site there is no set number of days per work element. A typical pathworker day is eight hours, but this must allow for walk in times, which may be accounted for separately.
Being able to locate and re-locate the exact place of survey is one of the most difficult parts of a good survey. Record as many locating features as possible - they must be easily located and permanent for identification by the pathworker.
Target notes on information contained on a standard specification survey sheet. Click to enlarge the image.
Completed survey sheets illustrating use of symbols to depict path condition and work required, with descriptive detail. See glossary of symbols for key. Loch Lomond and Trossachs Upland Footpath Condition Survey, 1998. The Footpath Trust, for Scottish Natural Heritage. Click to enlarge the image.
Data Collected
Four types of data are collected for a specification survey:
1. DESCRIPTION
- name of surveyor, weather conditions
- date of survey
- path and section identifier
2. MEASURES
- cumulative length along the path
- measurement at path condition and landscape features
- linear measurement of prescribed path repair
- path gradient where it steepens
- damaged path width and number of braids
3. PICTORIAL
- path condition - drainage problems/features, path damage and erosion features
- pathwork - drainage systems and techniques, path repair techniques, restoration work
- notable landscape features - fencing, dykes, trees, obvious bed-rock
- photograph points
4. PRESCRIPTION
- work to be carried out in note form, including sourcing of materials
- estimated number of constructed features required and work lengths or areas
- number of work days estimated for the work
Results
The written up survey sheets can be used as the pathwork specification, or the detail extracted to complete a full contract specification.
The path manager can use the quantified work and estimated work days to cost and plan the work. The labour costs will be calculated by taking the total number of work days expected and multiplying them by the average day rate charge for a qualified pathworker.
These figures, and a summary of specification details, may then be integrated with the path assessment management plan to provide a complete record of the proposed path management.