5. Develop Restoration Proposal and Mitigation Options

A method statement/project design/restoration plan should be produced for the restoration project, setting out the details of the proposed site works. It is important that this document includes specific sections on the peatland heritage, for example, highlighting how working methods will protect historic features, and what is required in terms of historic environment mitigation.

Method statements (detailing the methods used for peat restoration) should be drawn up and agreed with relevant historic environment stakeholders, prior to work commencing.

The following sections describe some of the ways to avoid/minimise incidental and accidental damage during peatland restoration work.

5.1 Avoiding damage during site works

It is important to recognise that harm to historic environment features can occur not just because of specific intrusive measures, but during site preparation and set up. The following measures could help reduce risks.

  • excluding sensitive areas from groundworks and vehicle movement (i.e. through traffic management), or using bog matting where these must be crossed (Figure 12). If a bog is too soft for a low ground-pressure vehicle to cross, then that area should be avoided.
  • using machinery that reduces impact, for example, low ground-pressure vehicles, tilt-rotator excavation buckets, and/or raising flail heads when removing Molinia (moor grass)
  • marking off known historic assets during works. This can include buffer exclusion zones around historic environment features and around access routes. Although buffer distances of 20 metres have been recommended by Association of Local Government Archaeological Officers (ALGAO) [Scotland] (2022), there should be some flexibility as actual buffer distance requirements might depend on, for example, the size of machinery. Any exclusion zone mapping in place should be communicated fully with the contractors. Methods that can be used to mark out exclusion zones can range from using canes and flags, to geofencing

5.2 Sustainable peat restoration methods

One way to avoid peatland restoration works impacting on historic assets is to use restoration techniques that minimise ground impact in sensitive areas on or near historic environment features.

Several methods use peat excavated from adjacent borrow pits to block ditches or create bunds to raise water levels (see Figure 13) artificially. These can range from a couple of pits next to a grip through to large-scale works across entire landscapes to create a network of cells.

Where the presence of archaeological or palaeoenvironmental remains has been demonstrated by the resource assessment (see section 3) or there is a high potential for their chance occurrence, these remains either need to be protected by using a restoration method that doesn’t impact on them, or recorded before or during the works (see section 5.4)

A range of options is available for blocking ditches and creating cell bunds (for example, see Thom et al 2019), and their use should be discussed with historic environment stakeholders to find the ones that are the most environmentally sustainable whilst still affording protection to the archaeological remains on site (see Figures 14a and 14b).

Other points to consider include:

  • avoiding damage to known historic features when harvesting heather brash for revegetation, for example, by not cutting in particularly sensitive areas or giving careful consideration to machine height clearances and ground pressures
  • avoiding the use of stone-built historic features (such as cairns or boundary walls) as sources of materials for stone dams
  • following existing forestry guidance on removal of trees from historic features during forest-to-bog restoration (see Forest Research 2023, Forestry England 2024)

5.3 Other ways to reduce risks

  • providing toolbox talks for contractors early on, explaining what to look out for during works and when to halt and ask for archaeological advice; this should be set out in an unexpected discoveries protocol
  • creating a risk log for the project – it is not possible to plan for every eventuality but having an idea of the likelihood of finding unexpected remains (e.g. archaeological finds) will help contingency planning (and funding). Regularly referring to and updating it as the project progresses will ensure situations do not escalate

5.4 Mitigation

In situations where peatland restoration leads to an unavoidable loss of, or disruption to heritage assets (either above- or below-ground), or change to their future accessibility for investigation, these assets need to be recorded prior to their loss or modification. This work might include a detailed survey or excavation of features that will be directly impacted by the restoration, undertaken before site work begins; or a programme of archaeological monitoring and recording undertaken during the restoration work (depending on the significance of heritage asset affected).

It is important that all project funders are aware that the work must also include subsequent analysis, reporting and archiving of archaeological or palaeoenvironmental remains, and budget accordingly (Figure 15).

The mitigation strategy should be appropriate and proportionate to the predicted impact of the works. All proposed archaeological work should be defined in a WSI, produced by the archaeological contractor or other suitably qualified archaeologist, approved by the relevant historic environment stakeholders. It is also advisable to consider if/how public engagement can be incorporated into the works.