Peatland ACTION case study: What’s the connection between peat and drinking water catchments?

What’s the connection between peat and drinking water? Peatland ACTION Communications Officer Fiona Mann, explains the importance of taking care of our peatlands as they have the potential to provide nature-based solutions to the water challenges we face in the 21st century.

Peatlands, or areas of land primarily made of partially decomposed organic plant material (mostly mosses) called peat, cover around 20% of the land in Scotland. They’re most prevalent on our western shores, due largely to our oceanic climate.

More people are increasingly recognising the value peatlands have, not least the crucial role they play in our drinking water catchments.

An estimated 10% of the planet’s freshwater is stored in peatlands, making the health of this habitat crucial for water security now and in the future. Up to 70% of Scotland's drinking water is sourced from catchments dominated by peatland habitat. Water derived from healthy peatlands is naturally of high quality with few pollutants and low nutrient levels, requiring straightforward treatment once it reaches a water treatment plant. However, the amount of dissolved organic carbon, which creates the brown colour of peaty water, is on the increase due to damaged peatlands. 

However, not all peatlands are in good condition. In Scotland alone it is currently estimated that over 600,000 hectares are in a poor condition as a result of historic land management decisions (drainage, burning and erosion). Where peat forming vegetation has been stripped away, the bare peat is left exposed and dries out.

Peatland ACTION has been funding restoration work to restore these peatlands throughout Scotland. This work is vital - to reduce the risk of flooding further downstream and decrease the amount of sediment washing into our rivers and drinking water reservoirs - like that undertaken at Sandy Loch in Shetland.

Sandy Loch drinking water catchment – What was the problem?

Sandy Loch has a 440 hectare catchment, that Scottish Water use to provide around 12,000 customers with drinking water on Shetland.

Land within this catchment is typical rough grazing which has been modified over decades, possibly centuries, from peat cutting for domestic fuel and pasture improvement for livestock.

Large areas of bare unvegetated peat within the Sandy Loch drinking water catchment were contributing to the high organic loading and brown water entering the loch, and ultimately the water treatment works. The peat was likely eroded as a result of a change in land management practices, and made worse by rain and wind erosion which washes the peaty soils into the loch. Although this water is perfectly safe to drink, it can require a lot of treatment before it reaches the quality that customers expect.

 

Peat pan stabilisation and sphagnum moss ‘plugs’

Stabilising the large areas of bare peat was crucial. This involved creating bog-pools over the area of exposed peat right next to the loch. The aim was to slow the flow of water, and trap and reduce the loss of peaty sediments into Sandy Loch. This also provides conditions to allow for the re-colonisation of bog plants, particularly sphagnum, a key ingredient in maintaining a healthy peatland habitat. To further encourage the re-colonisation process, sphagnum moss ‘plugs’ were added directly to the areas of bare peat.

Initial results of phase 1 indicated that these techniques worked well and further stabilization activities were completed on a larger scale during phase 2 in the summer of 2018. So far 27 hectares have seen restoration activities during phase 1 and 2, with a further 20 hectares planned to complete the project.

Reprofiling

Restoration activities also included reprofiling peat hags (overhang of bare peat). If these are left exposed to the elements (wind, rain and frost), the overhang would eventually collapse and large chunks of peat would be washed away. To prevent this, steep hag edges were reprofiled to about a 30 degree angle and vegetation stretched over the reprofiled surface. The vegetation also protects the peat from erosion by acting as a barrier to water, frost and wind.

 

Peatland ACTION on the road to… improved drinking water catchments

The partnership working between Peatland ACTION and Scottish Water's Sustainable Land Management Team means restoration activities at Sandy Loch has improved and protected the drinking water catchment. It is also expected to reduce the requirement for energy and chemicals used to treat the water in the future. Additionally, the work here will contribute to an improved aesthetic environment for those who visit the area. It is also contributing to and maintaining Scotland’s natural carbon storage and our resilience to climate change.

Acknowledgements

Peatland ACTION Fund (2018);
Peatland restoration advisors: Peatland ACTION Project Officer from Shetland Amenity Trust;
Project Planning and management: Members of Scottish Water’s Sustainable Land Management;
Sandy Loch landowners, and common graziers.
 

Award winning project

A TOTAL of 13 projects were recognised at the Shetland Environmental Awards in 2017.
Including the Scottish Water funded venture led by their Sustainable Land Management Team. Who were acknowledged for their peat restoration work at Sandy Loch treatment works on the outskirts of Lerwick.

The awards were judged by the Shetland Environment Group and they were sponsored by a host of organisations including NatureScot, Shetland Islands Council and VisitScotland, whose chief executive Malcolm Roughead presented the awards.

For further information, or to get involved with PeatlandACTION

Peatland ACTION case studies: We demonstrate links between peat condition and: fisheries; grouse; carbon storage; wildlife; landscapes; human history; and so much more. 

If you would like to contribute to the on-going work of Peatland ACTION please contact [email protected].

Project information: www.nature.scot/peatlandaction

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