Surveys

Before any restoration work takes place, Yorkshire Peat Partnership assesses sites using 3 stages of surveying. There may also be additional stone dam and Unmanned Aerial Vehicle (UAV) surveys on complex sites

Pre-Survey

This is the initial desk-based survey that takes place whenever we are asked to look at potentially restoring a site, usually by one of our partner organisations.

We acquire the relevant boundary and use aerial photography in MapInfo to digitise any visible grips, gullies, peat hags and bare peat so that they can be located during the field survey. This stage of the mapping also enables us to make an initial assessment of the type of work that may need to be carried out.

Once we have agreement for the survey to go ahead from all parties involved, we draw transects across the site which we can follow during the field survey. Drawing them prior to field surveying allows us to cover areas of erosion and unusual features that cannot be identified on aerial photography.


Field Survey

This is our assessment of the site on the ground. We upload the digitised features created during the pre-survey onto hand held GPS mappers and follow the pre-drawn transects across the site. We cross as many grips, gullies, hags and areas of bare peat as possible so that we can see the extent of any erosion in more detail.

Most of our field surveys are carried out during the autumn and winter months. This is because the vast majority of sites are privately owned grouse moors and we do not survey during the shooting season without pre-arranged permission. There is also a short window of opportunity for surveys in July between the breeding and shooting seasons.

We look at the width and depth of channels, height and slope of hags, note the type and extent of bare peat, and record vegetation communities and peat depth. All the records are uploaded into MapInfo to inform the post-survey mapping.


Post-Survey
The Post-Survey is the final desk-based survey of the area during which we use MapInfo and a combination of aerial photography and the walkover survey data to classify erosion features according to their type and size. We also add features that were not picked up during the pre-survey and delete anything that is not actually an erosion feature.

Once the post-survey mapping has been completed, we use MapInfo to calculate the quantities of each type of erosions. This is entered in to a Restoration Plan and, once all agreements are in place, it is ultimately used by contractors to determine the amount of material required and the cost of the restoration work.


Stone Dam Survey
On sites with large grips and small gullies, stone dams will be required to block the channels. Stone dams can also be effective in areas of shallow peat depth or where erosion has reached the underlying mineral.

The grips and gullies requiring stone dams are identified in MapInfo using both aerial photography and the field survey records. They are marked and the layers are uploaded to the handheld GPS mappers so that the drains can be located on site.

During the stone dam survey, surveyors walk the length of the grip or gully and accurately record the points that would be a suitable location for a stone dam. This will ensure the dams are at their most effective and that the stone can be dropped nearby from a helicopter lift.


Unmanned Aerial Vehicle (UAV) survey
Some sites have areas known as ‘dendritic areas’. They are intense networks of varying sized gullies in amongst peat hags and bare peat. They are very difficult to survey and the ground and to digitise using standard aerial photography.

For these complex sites we use a UAV to accurately map erosion features at the site. Subsequent geospatial analysis of this data allows us to model surface topography and hydrology in order to understand and quantify where best to carry out restoration work. By using this methodology to inform the restoration process we are better able to target our resources than would be possible using aerial photographs alone.