BUCKSTONES DAMS CONDITION AND EFFECTIVENESS

2011 ASSESSMENT

SURVEY GROUP

National Trust Volunteers

Marsden Moor West Yorkshire

2019

Executive Summary The National Trust asked the Survey Group in 2010 to carry out a study of the dams on Buckstones Moss primarily to assess their condition and identify what remedial works were needed. The study took longer than anticipated and became disconnected from decisions about which dams to repair, with some new structural work being done at the same time as the survey. The Group took the view that simply repairing the dams without assessing how they performed in the Buckstones environment would limit the choices open to the National Trust and decided to measure as many dam and gulley parameters as possible. In the event it took so long to complete the first ‘run’ of dams (Series B) that a reduced set of measurements was applied to the remainder. Recording less detail limited the depth of the analysis so that most of the observations about gulley channel gradient, side gradients and dam performance are based on Series B. The report is offered as a potentially useful account of the Group’s findings and not as a rigorous scientific investigation; the detailed records of numbered dams provide a baseline for future monitoring. While many scatter diagrams lack clear correlations, some of the deepest erosion is shown on the steepest channel slopes. Peat sediment has accumulated in most situations, but erosion pits below dams have been cut downstream over a range of gradients and these have led to severe undercutting of the dam, sometimes down to the mineral sub-stratum. Some but not all of the

accumulated sediment supports stands of Common cotton-sedge Eriophorum angustifolium and this has also spread over several of the slopes on the edge of gulleys. Other plants occur patchily, mostly but not exclusively on the gulley sides. Hare’s tail cotton-sedge Eriophorum vaginatum may form dense patches, even in the channel, and Crowberry Empetrum nigrum achieves high cover on some gulley sides, particularly at greater altitude. Out of the 457 dams monitored, 38% were found to be holding water. The number of dams holding water on each of the gullies varied from only 4% (on gully C) to 96% (on gully R), with on average 44% of the dams on any particular gully successfully holding water. 89% were found to be trapping silt >12cm deep, varying from 63% – 100% across the range of gullies. 74% of dams were found to be still intact in 2011. The number on each of the gullies varied from only 0% (on gully Q) to 100% (on gullies I,L,N & P), with on average 73% of the dams on any particular gully still being structurally intact after around 5/6 years of installation. The detection of water flowing between the peat base and the underlying mineral strata, deep cracks in the peat and the difficulty of making dams watertight in un-cohesive peat over a hard but erodible base raise questions about damming gulleys as a suitable strategy for achieving Favourable Condition on an area deemed to be degraded blanket mire on account of its deep peat. Work in Ireland by Dutch ecologists as part of an EU LIFE project demonstrated a link between the density of Sphagnum moss growth and the surface flow of water on lowland bogs. The capture of surface water on Buckstones by deep gulleys denies it access to potential Sphagnum moss growth on the mire surface and contributes to the erosion of ever deeper and wider gulleys. A detailed hydrological study of water movement is recommended, followed by a professional engineering solution to prevent further deterioration and to contribute to Favourable Condition on this Site of Special Scientific Interest and Special Area of Conservation. This may represent better value for money in the long term than frequent and often ineffectual repair of small wooden dams.

List of Contents

1. Background page 1

2. Aims of the Survey Group project page 2

3. Development of the field studies page 3

4. Series B – location and assessments page 3

5. Series B – Gradients, bare peat and vegetation cover page 6

6. Series B - Dam condition page 11

7. Overview of Series B page 14

8. The method applied to the ‘All Series’ survey page 16

9. ‘All Series’ physical gulley attributes and the vegetation cover: the channel page 17

10. ‘All Series’ physical gulley attributes and the vegetation cover: the sides page 19

11. Condition of dams over all series page 21

12. Discussion and conclusions including those from K Quantrell 2013 page 21

13. References page 24

Annex 1 Full dataset for Series B page 25

Annex 2 Summary dataset for all other series page 27

This report was produced by volunteers of the National Trust’s Marsden Moor property in West Yorkshire. Although signed off by the National Trust at Marsden the views and opinions it expresses are those of the volunteers and may not be coincident with those adopted by the National Trust.

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1. Background The deep peat (range in series B, 1m – 2.2m) of Buckstones Moss lies on the almost south-facing slope of a ridge trending W-SW to E-NE and peaking at 482m aOD. The slope on which it is formed is crossed downslope by the A640 road, beyond which the land steepens even more down towards the March Haigh reservoir. Overall there is a drop of around 40m on Buckstones Moss from watershed to road, a distance of just over 620m forming an overall slope of 1 in 15, though this is not uniform, being made up of steeper and flatter stretches. Where exposed, the land underlying the peat bears flattish gritstone rock fragments presumed to be of local origin above the Midgley Grit of the Marsden Formation (Figure 1), though most of this stratum is concealed below the peat. The Midgley Grit shows a broadly southward-fining trend, from coarse-grained and locally pebbly in the north around Pule Hill to fine- to medium-grained around Heyden Brook about 10 km to the south-east. Its dip angle is 3 degrees towards the south-east (Waters et al., 2012). South of the road the slope bears rock fragments and landslip material upslope of a mudstone marine band. The rock fragments beneath the peat are loosely embedded in sands, gravels and finer sediments to varying degrees of hardness and this affects the extent to which they have been eroded in the channels north of the road. The peat is deeply fissured by channels formed by rapid surface-water run-off and in some places the water erosion has cut right through the peat revealing the material described above. It is assumed that the erosion is highly episodic as it was rare to see any water flowing through the channels during survey visits despite the copious erosion features. Lack of cohesion in the peat has been exacerbated by deep peat fires leaving large bare patches in the vegetation between the channels, such as occurred in May 2008. Some channels join with others further downslope, the cumulative volume increasing the erosive power of the flowing water. In a few places the flow was observed to be subterranean mostly through concealed peat pipes and these are prone to collapse. Rapid increments in peat erosion were noted by the National Trust and several series of wooden dams were built across the channels in 2005/6 by volunteers. The standard design was a single upright post either side of the channel with close-fitting horizontal boards nailed to them, embedded in the peat on each side and beneath; a notch was cut in the upper surface of the top board to carry the water flow. The frequency of dam emplacement was determined by the slope, with the potential ponded water level arising from one dam determining the place for the foot of the next in an uphill sequence, though the rationale may not have been followed strictly in all cases. Although using volunteer labour the construction of approximately 430 dams involved significant expenditure and it is important to know if its use has been justified in halting peat erosion, stabilising the surface and enabling active blanket mire to develop. The National Trust’s Marsden Moor Estate volunteer Survey Group undertook to review the performance of the dams commencing in 2011 employing a range of techniques applied with different degrees of detail. The results were appraised in February 2013 but not assembled in detail until 2019.

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Figure 1 Geology of the Buckstones area

Source maps for the above are ©British Geological Survey and stream courses © Ordnance Survey

2. Aims of the Survey Group project These are summed up in a paper by Katie Quantrell written in February 2013, and taken from the National Trust’s Moorland Management Plan 2006-2016. Specifically: 1) Are the dams holding water? 2) Are the dams retaining peat?

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3) Are the dams retaining structural integrity and longevity? Beyond this, the Group wanted to find out as much as possible about how factors such as slope affected the dams’ ability to preserve their structure and support revegetation to heal the erosion by allowing peat-forming vegetation to become established.

3. Development of the field studies The locations of dam series A to T (plus an AA series and two others without an identifying letter) are shown in Figure 2. The same Figure also provides context using the Ordnance Survey 1:25,000 scale map on which inter alia contours are shown at 5m intervals. Given the large number of dams and the need to provide synoptic advice about their condition to the National Trust, the most detailed series of measurements was confined to Series B, the most easterly tier of dams stretching from the watershed to half way downslope towards the A640 close to the 460m contour. Below this and down to the road the smaller channels join to form larger ones within wide gullies containing a flatter bottom on a more gentle slope through which there is a narrower sometimes meandering channel. The rationale behind the taking of measurements evolved as the complexity became clearer. Starting from the bottom of Series B a very wide range of information was collected about the slope, integrity and vegetation of the gulley channel, the floor beside the channel if present, the slope on both sides and the vegetation at the top of each slope. The full spreadsheet is provided in Annex 1. Given the large number of dams and gulley sections to be examined beyond Series B its results were used to arrive at a slimmed down set of observations. The full set of summary results is given in Annex 2 and extracts based on it in Figures 17 to 27. 4. Series B – location and assessments In Series B, channel slope and the slope of the banks on either side were measured using a tape and an automatic level, dividing the vertical height by the horizontal distance occupied by the slope to give a 1 in x slope index, where x is the horizontal distance. In some Figures this has been converted to a percentage. The gulley floor where present, like the banks, may be bare peat or vegetated, and the cover of the major plant species was noted using a percentage score. A similar score was used for plants forming the vegetation in un-eroded peat either side of the gulley. The zones corresponding to the measurements are shown on Figure 3, though it would be hard to find a single example that is typical of all. As some of the subsequent Figures show, the channel is sometimes scarcely discernible while in other locations it is deeply incised with bare peat on the sometimes vertical sides and extending beyond onto the open moorland. An extensive flat valley floor either side of the channel, was mostly found downslope of the dammed lengths of each gulley, and was absent in Series B. The condition of each dam was assessed as intact or leaking around the sides, through the planks or underneath the planks. Overflow had in some cases eroded a pit downslope of the dam, and this was noted, alongside whether the peat was breached through to underlying strata here or at any other point along the course of the gulley. Some gulleys, particularly at lower altitude, had accreted silt and this could be bare or colonised by plants, particularly Common cotton-sedge Eriophorum angustifolium.

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Figure 2 Labelled series of dams on OS 1:25,000 scale map Base map © Ordnance Survey

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Figure 3 Measured zones around a dam. Series B Dam 59

Adjacent moorland

Bank

Floor

Channel

Dam Bank

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Figure 4 Slope gradient along the Series B dams (numbers 60-22) The plotted gradients are for the lengths of gulley between dams.

5. Series B – Gradients, bare peat and vegetation cover Gradients occur in two planes. There is the channel gradient determined by the slope of the land into which the gulley is cut and then two gradients, one either side of the channel and at right-angles to it, representing the degree to which the flow has cut into the peat and how the sides have subsequently weathered. There is a third, not considered in this report, reflecting the degree to which the non-eroded peat either side of the gulley has slumped as a consequence of dewatering, oxygenation and concomitant decomposition, parallel with the gulley. Figure 4 shows there is a consistent channel gradient of approximately 5% - 8% (1 in 20 to 1 in 12.5), but exceptionally this peaks at around 30% (1 in 3.3) close to Dams 54 and 46-45 (Figure 5). As is recorded in Figure 6, the gradients along the sides of the gullies can be much greater, the steepest being around 130%. It is worth noting that a 45o slope is 100%, or 1 in 1. A very large amount of information was collected about the slopes and the relative covers of bare peat or vegetation, and this was extended outside of the gulley for a strip of around 10 metres, going beyond the zone in which the peat had been visibly affected by decomposition and slumping. This has been separated from the information about the physical characteristics of the gullies and the dams in Figure 6

Dam 60 59 58 57 56 55 54 53 52 51 50 49 48 47 46 45 44 43 42 40 39 38 37 36 35 34 33 32 31 30 29 28 27 26 25 24 23 22Distance m 0 12 18 22 25 26 29 35 40 46 51 57 61 68 69 72 77 81 83 86 91 93 94 98 102 105 109 112 116 121 125 129 133 135 137 141 144 147

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Figure 5 Dam 45 on 1 in 3 slope

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Figure 6 Bare peat and vegetation distribution along the Series B gulley from bottom (Dam 60) to top (Dam 22), ordered according to gulley zones

Dam number: 60 59 58 57 56 55 54 53 52 51 50 49 48 47 46 45 44 43 42 41 40 39 38 37 36 35 34 33 32 31 30 29 28 27 26 25 24 23 22Moorland west (10m strip)Bare peat % 10 50 5 0 0 3 5 5 0 5 20 20 50 100 5 30 0 40 40 40 20 0 0 0 0 0 0 0 10 5 30 15 5 0 20 0 5 5 5Vegetation % 90 50 95 100 100 97 95 95 100 95 80 80 50 0 95 70 100 60 60 60 80 100 100 100 100 100 100 100 90 100 70 85 95 100 80 100 95 95 95Common cotton-grass % of veg 1 2 5 3 10 15 10 10 5 15 15 5 20 5 5 5 10 30 40 35 25 10 15 15 15 30 5 10 30 5 5 5 2 5 2 2Hares tail cotton-grass 15 85 40 55 35 30 35 15 20 5 30 80 50 40 20 5 10 10 10 2 15 5 10 5 2 2 5 20 20 10 15 10 20 60 75 80 80Heather (Ling) 5 10 40 35 35 30 45 30 30 60 30 20 30 20 50 80 75 75 70 65 55 45 65 35 35 70 65 25 50 30 15 5 5 5 5Bilberry 45 5 5 5 5 5 15Crowberry 1 7 15 10 20 20 40 35 20 10 5 10 + 5 5 10 20 10 10 15 10 35 5 15 5 30 10 10 10 10non-Sphagnum moss 30 5 10 30 5 20 15 10 5 10 10 20 5 10 2 2 3 5 5 20 20 15 10 5 10 5 5 2 2 25 10 25 10 10 10 5Lichen 5 3 10 10 5 + 5 2 2 2 2 2 5 15 10 15 5 2 2 2 10 10 10 2 5 5 5 2 2Wavy hair-grass/Sheep's fescue 5 3 3 5 10 2 5 30 35 5 15 10 20 10 5 15 35 60 30 15 10 10Purple moor-grass 3 5 5 2

West side gradient % 13.59 20.28 67.30 109.58 80.44 74.61 107.08 59.19 40.96 25.50 27.27 17.74 18.57 13.60 3.20 21.05 42.86 40.00 18.11 24.64 36.50 42.00 46.92 13.13 12.35 32.27 118.75 30.71 56.47 50.77 49.29 48.46 59.00 20.91 44.38 19.06 128.33 123.33 60.00Bare peat % 5 98 95 100 100 50 15 15 60 10 15 50 80 100 20 50 30 97 97 100 5 80 5 5 0 50 15 85 70 60 0 60 95 40 95 95 95 95Vegetation % 95 2 5 0 0 50 85 85 40 90 85 50 20 0 80 50 70 3 3 0 95 20 95 95 100 50 85 15 30 40 100 100 40 5 60 5 5 5 5Common cotton-grass % of veg 2 50 95 10 15 40 30 5 40 50 80 5 60 80 75 95 45 80 55 15 95 45 10 70 70 5 90 80 95 50 90 100 95 95Hares tail cotton-grass 15 3 75 35 10 30 40 10 30 70 70 45 10 2 5 90 25 15 15 15 10 5 5Heather (Ling) 10 2 10 45 20 15 40 40 20 30 45 20 20 25 2 55 20 40 40 35 5 15 5 10Bilberry 5Crowberry 50 10 5 2 5non-Sphagnum moss 20 2 10 15 20 30 5 10 5 10 5 15 10 10 40 10 15 20 2 2 2 2 5 2 5 5Lichen 5 + 2 + 20 + 5 5 2 2 2 2Wavy hair-grass/Sheep's fescue 10 15 5 20 10 5 60 10 5 5 25 5

Gulley floorBed gradient to next dam 0.26 9.17 12.80 11.86 30.18 20.56 1.81 8.35 7.18 6.18 6.19 2.26 0.69 29.00 16.43 5.34 3.44 13.64 5.81 3.40 4.09 17.86 3.06 6.59 -1.88 7.07 2.50 7.50 6.59 6.34 8.37 7.14 3.10 6.43 1.67 5.94 8.26Bare peat % 0 98 50 99 100 75 35 50 20 90 90 100 100 100 80 100 100 90 100 100 100 80 95 20 10 55 60 95 95 55 50 10 30 95 80 100 95 95 95Bare mineral % 47Vegetation % 100 2 3 1 0 25 65 50 80 10 10 0 0 0 20 0 10 20 5 80 90 45 40 5 5 45 50 90 70 5 20 0 5 5 5Common cotton-grass % of veg 55 4 100 10 5 30 85 100 100 + 30 100 95 100 100 90 100 100 70 100 100 100 95 95 100 100Hares tail cotton-grass 5 95 85 50 60 15 55 30 5 5 100Heather (Ling) 5 3 45 15 100non-Sphagnum moss 1 2 10Wavy hair-grass/Sheep's fescue 25 1 10 100 5

East side gradient % 57.38 108.18 80.50 96.10 93.79 81.29 109.31 121.50 105.00 84.18 31.82 10.67 10.81 16.51 9.30 4.76 11.67 96.25 59.38 53.75 68.18 86.67 41.50 44.12 72.86 59.33 27.60 75.29 109.09 64.00 93.68 46.06 18.13 46.50 32.63 37.33 21.43 98.00 34.55Bare peat % 10 40 50 50 30 5 10 5 10 10 5 0 15 5 20 5 20 75 75 95 45 30 85 15 25 5 20 90 95 25 5 5 45 95 45 95 95 98 95Vegetation % 90 60 50 50 70 95 90 95 90 90 95 100 85 95 80 95 80 25 25 5 55 70 15 85 75 95 80 10 5 75 95 95 55 5 55 5 5 2 5Common cotton-grass % of veg 10 93 10 10 15 3 35 10 20 18 15 15 10 7 40 20 65 100 50 100 95 90 35 25 45 85 45 95 100 100 80 35 90 85 30 95 95 100 75Hares tail cotton-grass 45 2 40 65 35 40 20 30 45 18 20 5 20 7 20 5 20 35 2 5 5 5 10 3 25Heather (Ling) 10 40 25 50 35 40 55 25 50 60 60 20 80 20 70 15 50 3 30 50 30 10 40Crowberry 2 + 5non-Sphagnum moss 30 5 20 5 10 20 25 10 10 10 10 20 50 7 20 5 5 10 2 60 10 45 20 10 15 2 50 5Lichen 5 2 + 2 2 2 15 2 5 2 2 5Wavy hair-grass/Sheep's fescue 20 15 15 10 5 10 5 30 10 5 10 2

Moorland east (10m strip)Bare peat % 0 5 0 5 5 10 0 0 0 0 0 0 0 0 0 0 0 5 5 20 0 5 5 0 5 0 2 5 10 0 15 0 10 10 20 10 40 0 10Vegetation % 100 95 100 95 95 90 100 100 100 100 100 100 100 100 100 100 100 95 95 80 100 95 95 100 95 100 98 95 90 100 85 100 90 90 80 90 60 100 90Common cotton-grass % of veg 2 10 5 5 3 5 55 70 15 15 25 + 5 5 5 15 10 5 5 5 20 10 5 5 5 5 5 5 10 5 20 10 10 5 5 5 30 15 20Hares tail cotton-grass 45 65 80 40 30 30 20 5 10 15 30 10 15 15 5 15 + 10 20 15 10 10 10 20 15 20 20 55 30 25 20 20 20 25 35 50 50 45 35Heather (Ling) 10 15 10 35 40 40 20 15 30 30 40 80 80 80 80 60 80 80 75 70 70 65 70 45 30 40 40 25 35 10 20 20 10 10 20 15 10 5 10Bilberry 2 3 5 5 15 15 10 10Crowberry 5 10 5 + + + 5 + 2 10 5 10 10 15 15 60 30 40 55 30 30 20 5 10 20non-Sphagnum moss 35 10 20 30 40 25 30 10 40 30 5 10 + + + 10 10 5 5 10 20 60 45 15 45 10 5 5 5 15 2 5 2 20 20 10 10 10 15Lichen + + + + 2 3 5 5 25 40 10 15 15 5 5 2 2 10 10 10 15 2 2 2 2Wavy hair-grass/Sheep's fescue 10 3 25 20 20 10 10 2 2 2 15 5 20 5 10 5 20 5 10 15 10 15 10 5

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Figure 10 (out of sequence) Full set of observations on dams and channel condition for Series B

dam number 60 59 58 57 56 55 54 53 52 51 50 49 48 47 46 45 44 43 42 41 40 39 38 37 36 35 34 33 32 31 30 29 28 27 26 25 24 23 22dam type (W, HB, S, Other) W W W W W W W W W W W W W W W W W W W W W W W W W W W W W W W W W W W W W W Wwater marks on planks Y/N N N N N N N N N N N N N N N N N N N N N N N N N N N N N N Y Y N N N N N N N Ndistance sill to HWM n/a n/a n/a n/a n/a n/a n/a n/a n/a n/a n/a n/a n/a n/a n/a n/a n/a n/a n/a n/a n/a n/a n/a n/a n/a n/a n/a n/a n/a 0.2 0.07 n/a n/a n/a n/a n/a n/a n/a n/a

ConditionIs dam holding water? Y/N ? ? N N N N Y N ? ? N ? N ? N ? ? N ? ? ? Y Y Y Y Y Y Y (Y) Y Y Y Y Y Y Y Y Y YDoes water leak Under or Around the dam?

N U U/A U U Y U U U N N N N U N U N N U U A N (U) N N N N Through A A Through N N AU A A A A A

Is dam trapping sediment? Y/N

N Y N Y Y Y Y N Y Y Y Y Y Y Y Y Y Y Y Y Y Y Y Y Y Y Y Y Y Y Y Y Y Y Y Y Y Y Y

How far back does water extend from the dam (m)?

none peatpeat/ sand

peat peat none 0.16 none none none nonebare peat

bare peat

bare peat

bare peat

bare peat

bare peat

bare peat

bare peat

bare peat

bare peat

bare peat

peat/ veg

peat/ veg

none 3.8 1.8 2.4 2.8 2.5 pools pools none none none 2.8 1.9 2.8 none

pit depth (m) n/a 0.45 n/a n/a 0.35 n/a 0.2 0.3 n/a n/a 0.15 0.35 0.25 0.25 0.15 0.2 n/a 0.35 0.2 0.6 0.2 0.2 0.35 0.1 0.15 0.14 0.13 0.12 0.22 n/a n/a n/a n/a n/a n/a n/a n/a n/a 0.4pit length (m) n/a 0.57 n/a n/a 0.92 n/a 1.5 0.4 n/a n/a 0.5 0.8 0.4 0.2 0.35 0.3 n/a 0.5 0.6 0.85 0.8 0.65 0.6 0.65 0.14 1.1 1 0.7 1.2 n/a n/a n/a n/a n/a n/a n/a n/a n/a 0.7Is dam Intact, Disintegrating, Rotting, Eroding, Undermined?

I U U U E I I E E I I I I E I E I I E E E I (E) I I I I I D E I I I E E E E E E

Is maintenance required (Y/N)?

N Y Y Y Y N N Y Y N Y N N Y N Y N N Y Y Y N (Y) N N N N Y Y Y Y N N Y Y Y Y Y Y

sill elevation (level, as calculated from benchmark)

10.059 10.344 10.656 10.997 11.197 11.785 12.079 12.399 12.644 12.994 13.544 13.664 13.784 14.074 14.514 14.754 14.894 15.074 15.194 15.314 15.464 15.614 15.704 15.844 16.054 16.174 16.354 16.624 16.894 17.044 17.324 17.514 17.704 17.844 17.904 18.054 18.264 18.464

water surface upstream relative to benchmark, m

none none none none 10.797 11.147 11.485 11.599 12.149 none none none none none none none none none none none none none none none 16.014 15.834 15.914 16.384 16.514 16.624 none 17.154 17.514 17.664 17.804 17.904 18.044 18.254 18.454

water surface downstream relative to benchmark, m

none none none none 10.447 10.817 11.735 11.599 11.869 none none none none none none none none none none none none none none none none none 15.824 16.044 16.334 16.494 16.654 16.914 17.254 17.514 17.704 17.834 17.904 18.084 18.244

peat surface relative to benchmark upstream

9.008 9.335 9.775 10.502 10.737 10.897 11.205 11.550 11.949 12.514 13.034 13.534 13.674 13.464 13.984 14.394 14.664 14.794 15.074 15.124 15.264 15.374 15.324 15.404 15.614 15.734 15.714 16.134 16.154 16.464 16.734 17.074 17.404 17.644 17.794 17.854 18.024 18.204 18.364

peat surface relative to benchmark downstream

8.978 9.009 9.55 10.113 10.445 10.777 11.435 11.540 11.949 12.344 12.684 13.074 13.144 13.194 13.484 13.944 14.254 14.364 14.664 14.574 14.844 15.014 15.104 15.354 15.464 15.734 15.674 15.964 16.034 16.334 16.624 16.884 17.244 17.494 17.584 17.674 17.744 17.934 18.124

peat depth above dam m 1.11 0.52 0.34 0.47 0.45 0.74 0.67 0.68 0.68 0.62 1.42 1.12 0.82 0.33 0.7 0.95 0.82 0.74 0.85 0.9 0.8 0.79 0.61 0.71 0.85 0.84 0.66 1.04 0.86 1.08 1.1 1.22 1.24 1.45 1.51 1.5 1.44 1.35 1.56peat depth below dam m 1.11 0.11 0.26 0.39 0.1 0.39 0.34 0.55 0.43 0.73 0.95 0.75 0.42 0.28 0.22 0.54 0.5 0.63 0.5 0.73 0.42 0.46 0.51 0.64 0.8 0.74 0.48 0.8 0.57 0.9 1.08 1.01 1.12 1.33 1.29 1.28 1.02 1.44 1.35

How far upstream does open water extend? Soft peat?

? peat peat ? peat peat 0.16 ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? 3.8 1.8 2.4 2.8 2.5 pools pools ? ? ? 2.8 1.9 2.8 ?

floor/channel shape curve kink straight straight straight. straight straight kink straight ? curve ? ? ? ? ? ? ? ? ? straight curved straight curved straight ? straight straight curved ? ? ? ? ? ? ? ? ? ?

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As Figure 5 shows, the channel is often devoid of vegetation, but in others Common cotton-sedge Eriophorum angustifolium is the primary colonist, though other species such as Hare’s tail cotton-sedge E. vaginatum, Common heather Calluna vulgaris and the grasses Deschampsia flexuosa and Festuca ovina also occur (tabulation in Figure 6). To explore whether gradient has influenced the development of vegetation in the channel it is plotted against the cover of Eriophorum angustifolium in the channel in Figure 7. There is little correlation between the gradient and the development of cotton-sedge in the channels though it was not found in channels steeper than 18%. On these extremely steep slopes the channel was bare peat and (from memory) had signs of recent erosion. Once established the sedge may occupy the entire space to the exclusion of other plants (Figure 8). No Sphagnum moss was found in any of the channels in which Eriophorum angustifolium had become established. There is some indication of that points cluster at the low and high ends of the cover range. Although channels are prone to erosion they also receive loose peat eroding from the side slopes. While this may also be washed away by the flow when in spate it may also smother seedling plants before they become established.

Figure 7 Percentage cover of Common cotton-sedge Eriophorum angustifolium in the channel plotted against gradient.

Slopes on the gulley sides can be much steeper than those along the channel. Values ranged from negligible to around 130%, or 1 in 0.8, with the likelihood that instability and peat erosion would be positively correlated with the increase in slope. The scatter diagram in Figure 9 shows that the cover of bare peat (the converse of vegetation cover) does not suggest any degree of correlation with the intensity of the slope. This is a somewhat surprising outcome and it is hard to find a plausible explanation. It is possible that vegetation on the flatter moorland survives the shifting of the peat below it and can then root after it has slumped onto the otherwise unstable slope.

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Figure 8 Channel and gulley sides with dense cover of Common cotton-sedge Eriophorum angustifolium around Dam 29

Figure 9 Scatter diagram of the percentage of bare peat on both gulley slopes of Series B against gradient in which the vertical component of the slope is expressed as a percentage of its horizontal footprint.

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The same species of plant are found on both sides of the gullies within the un-eroded moorland (tabulation in Figure 6). There is clustering of, for example, Calluna vulgaris as the dry heath elements increase at the expense of the species more typical of blanket mire. Altitude rises in Series B from Dam 60 to Dam 22 and some species show an increase in cover over the range. Crowberry Empetrum nigrum cover increases with altitude on the east side but is also present lower down on the west side. There is an apparent increase in lichen cover and both of the fine-leaved grasses Deschampsia flexuosa and/or Festuca ovina (survey does not discriminate) with altitude on the west side, but the grasses are well-represented at lower altitude on the east. It is likely that the time since the last moorland fire, its intensity and the degree of recovery are as potent influences on the vegetation at the relatively small altitude range (approximately 9.5 metres) spanned by Series B. Overall, Common cotton-sedge Eriophorum angustifolium is the commonest colonist of the gulley floor (channel) and can reach 100% cover anywhere except on the steepest gradients; it has not necessarily done so, and many lengths of the channel remain bare. Hare’s tail cotton-sedge E. vaginatum is also found along the channel, but is ‘occasional’ on the DAFOR scale. Although much of the gulley side is bare, species found on the un-eroded moorland are all found at points along Series B. These may represent redistribution by slumping or the seeding in of new plants. 6. Series B - Dam condition The ‘condition’ category includes that of the wooden dam and of the channel bed close to the dam. The full set of observations are given in Figure 10, out of sequence on the larger page 8. A further synopsis of the major attributes is given in Figure 11.

Figure 11 Summary of the condition of thirty-nine dams in Series B from information given in Figure 10.

Approximately half of the dams were judged to no longer hold back any water, the most common leakage being underneath the dam. Leakage around the edge of the dam was the second most common with both conditions in two dams. Peat sediment had been trapped by most dams, providing a potential base for plant growth, but pits had been eroded downstream of more than half the dams, contributing to the increased likelihood that leakage would occur underneath them. The longest pit extended for 1.4m, the deepest was eroded to a depth of 0.45m. It remains unclear

Y N Y Ndepth

range mlength

range m36 3 23 16 0.1 - 0.45 0.14 - 1.5

Sediment trapped?

Pit formed?

IntactDisinte-grating

ErodingUnder-mined

Y N

19 1 16 3 23 16

Condition Maintenance required?

Yes No ? Under Around U & A Through

19 9 11 11 8 2 2

Holding water? Leak points

- 13 -

whether the sediment is redistributed whenever large volumes of water pass down the series, but topography suggests that channel erosion may still occur and this would include silt redistribution. Overall, the basic wooden structure was intact in only 19 (about half), the damage in the remainder contributing to leakage, mostly as a consequence of erosion to the channel. It was judged that maintenance was required on slightly less than half of the dams. All the dams were installed in the peat. Thickness is variable, ranging from 0.33m to 1.56m. When surface elevation is plotted against that of the peat:mineral interface (Figure 12) it shows that, although there is a trend towards deeper peat at greater altitude there are also thicker and thinner patches along the series, due to uneven-ness in the sub-peat base or at the surface.

Figure 12a Elevation of the channel peat surface (blue) and peat:mineral interface (red) along Series B from lowest (Dam 60) to highest (Dam22). The mean surface elevation beyond the gulley is included (grey). Figure 12b Peat depth in the channel along the above transect.

The underlying mineral deposits are exposed at points along the channel. For example, Dam 57 lies about 23m along the x axis of Figure 12b where the peat is around 0.4m thick. Figure 13 shows that the peat base has been eroded to expose the mineral substratum on a relatively steep 12.5% gradient.

- 14 -

Figure 13 Series B including Dam 57 where the peat is thin along the deeply-cut channel with 12.5% gradient.

The depth to which the channel has cut into the original peat profile (grey dots) is not uniform. At approximately twenty metres from the origin the channel has cut deeply and is now close to the sub-peat stratum, but has cut less deeply than in similar depths of peat deposit further up the slope. This may reflect the gradient though the Excel ‘trend line’ in Figure 14 shows a very weak positive correlation overall.

Figure 14 Scatter diagram of depth of cut into the peat at a range of channel bed gradients. Depth of cut was calculated by subtracting the elevation of the channel bed from the mean elevation either side of the gulley.

The relationship may be complicated by the development and then collapse of peat pipes. While there was no direct evidence of past peat pipes along Series B it was observed along other drainage lines. In these, water was flowing along the peat:mineral interface between and even within sections of open gulley. It is possible that peat pipes can be initiated when overflow from a dam creates a pit in the channel bed downstream of the dam. Although it did not involve a peat pipe, a pit is shown in Figure 15.

- 15 -

Figure 15 A pit created downstream of Dam 24 by water overflowing the dam via the notch.

Figure 15 also shows the degree to which peat silt has collected in the channel both upstream and downstream of the dam (as the upstream of the next dam down the series). 7. Overview of Series B The channel spans an elevation of around 11 metres over a distance of 140 metres. It has 39 wooden dams along the surveyed length more than half of which require maintenance. They fail to hold back water because of leakage underneath, around the sides or through the planks, though peat silt has accumulated in nearly all the inter-dam channels. In some cases water overflowing the dam notch, presumably when in spate, have eroded pits in the sediment or in situ peat with the risk of engendering peat pipe flow. There is evidence that, when installed, the dams did hold back water at times other than when in spate (Figure 16).

Figure 16 Downslope from Dam 22 (top of Series B) on 11 March 2009 soon after installation.

- 16 -

The lack of significant water in the channels at the time of survey coupled with the evidence of erosion and redistribution of sediment suggests there is a very discontinuous but voluminous flow of water down the series. It has been sufficient in the two years following Figure 16 to develop the damage and leaks recorded in this survey. The depth to which the force of the flow has cut into the peat is not well-correlated with the original depth of the peat but much of the cutting is likely to have occurred before the dams were installed. The sub-peat stratum has been exposed in some locations but this is not necessarily where peat was originally thinnest or where the gradient, and thus the energy of the flowing water, was greatest. Although copious silt has accumulated in the channel its revegetation is very partial and again not well correlated with gradient. There are instances where Eriophorum angustifolium, as the most common primary colonist, has developed over the channel bed and on the gulley sides and others where both are still bare peat. Given that the dams had only been in place for a small number of years it would be too early to evaluate their effectiveness in promoting a cover of vegetation on the channel bed. Ideally, the cotton-sedge would provide a nurse crop for the development of Sphagnum mosses to form types of vegetation, such as NVC community M6 mire, as found in ditches and gulleys in the locality. The aim of damming is not only to create an aquatic environment upstream of a dam, but to arrest peat erosion and introduce a regime in which bare peat surfaces heal with vegetation and provide resistance to future erosion. Beyond this, the increase in wetness along the gulley would reduce the hydraulic gradient between it and the surrounding moorland, thus assisting the aim of blanket mire restoration. In practice, the installation of wooden dams at the prescribed intervals along the gullies is unlikely to achieve this because the energy of flowing water when in spate is too great for the dams and their junctions with the peat to withstand and the latter is soon eroded. Peat has no cohesive strength and any disturbance, such as forcing planks or plastic sheets into it, is likely to create a path that can be exploited by flowing water and then be eroded to become bigger. Generally speaking, the gradient and flow-volumes on Buckstones is too great for wooden dams to be effective.

- 17 -

8. The method applied to the ‘All Series’ survey The full set of dam series is shown in Figure 2. Cumulatively this gives a total of 457 dams, too many to apply the same scrutiny used for Series B in which individual inter-dam lengths of gullies were examined. Instead, individual inter-dam lengths were aggregated to give 77 lengths for the comparisons. Figure 17, in which measured channel gradients of Series B are compared with the gradient intensity classes used for this analysis, shows how detail has been diminished by the aggregation.

Figure 17 Comparison of degrees of slope as used in the detailed analysis of Series B with the descriptors used for the ‘all series’ comparison.

In aggregating lengths of channel there is a loss of positive correlation with the measurements used in Series B. For example, describing an aggregate length as moderate may have to accommodate variation ranging either side of moderate. Similarly, in expressing a mean slope in degrees by averaging individual Series B measurements within each aggregate does not produce a ‘real’ figure and this further blurs the validity of making the above comparison. This difficulty underlies the anomalies between the ‘interpreted range % gradient’ and the ‘mean gradient’ in Figure 17; however, all these difficulties notwithstanding, it is felt that Figure 17 still has some value in explaining the link between the way in which gulley floor gradient is described in the detailed assessment of Series B and the more general descriptive approach used in the analysis of the complete series complement. The gradient of gulley sides is also described differently in the full set analysis from the approach in Series B. For the detailed Series B analysis the gulley side slope was recorded as the vertical change expressed as a percentage of the horizontal footprint. In this full set analysis the slope is expressed in degrees, with the potential range lying between 0o and 90o. Figure 18 is provided to illustrate the relationship between the two ways of expressing the gradient.

Figure 18 Comparison of the two ways of expressing the gulley side gradients and the number of inter-dam aggregates found within each. While either method is adequate to describe slopes of up to 45o the percentage method becomes unwieldly as it approaches 90o. This is because the length of the horizontal footprint is zero for a 90o angle and it is simply described in the table as ‘vertical’; it is mathematically impossible to divide by zero. Fortunately, none were overhanging and thus greater than 90o.

58-60 4.71 Slight 147-49 1.48 Moderate 2-322-37 5.25 Moderate 4-837-47 11.00 Mod/Steep mixed49-58 11.68 Steep >8

Series B dam

sequence

mean % gradient

gradient descriptor

interpreted range % gradient

range in degrees

range mean as

slope in %0-9 7.86 0

10-19 25.83 1620-29 45.66 3030-39 68.96 4040-49 98.04 9750-59 140.25 2960-69 209.64 1370-79 361.02 2180-89 1041.67 25

90 vertical 29

slope

total

- 18 -

Reporting on the proportion of gulley sides in each slope category was also complicated by how it was recorded in the field. In practice it was found to vary along most lengths so the most and least severe estimates were recorded. These had to be accommodated in the analysis so each length was deemed to have two slope estimates, the steepest and the least. As this would over-represent the lengths given as ranges, those with a single slope estimate were counted twice. 9. ‘All Series’ physical gulley attributes and the vegetation cover: the channel As in the detailed analysis of Series B, all aggregated lengths of gulley were assessed for channel slope, side slopes and the cover of the main plant species versus bare peat. The verbal descriptors used for channel (gulley floor) slope means plotting this variable against others is not feasible.

Figure 19 Distribution of aggregated gulley lengths between channel gradient descriptor classes. The third column is an approximation to % gradient as used in the detailed analysis of Series B.

Figure 20 Gulley width expressed as the number of aggregated lengths within each width range class. Figure 21 Proportion of bare peat in aggregated gulley lengths

Bottom slope descriptor

number of

lengths

estimated % gradient

Very steep 3 >12?Steep 15 >8<12?Steep/mod 2 6Moderate 28 4Mod/slight 4 2Slight 22 1Slight/flat 2 0.5Flat 2 0

width range m

number of

records% of total

0 2 1.30.1-0.5 23 14.930.6-1.0 62 40.261.1-1.5 53 34.421.6-2.0 8 5.192.1-2.5 5 3.252.6-3.0 0 03.1-3.5 1 0.65

Average gulley width m 1.03Minimum gulley width m 0Maximum gulley width m 3.5

Bare peat as % cover

number of gulley lengths

% of gulley

lengths0 9 10.71

1-10 11 13.1011-20 9 10.7121-30 9 10.7131-40 7 8.3341-50 7 8.3351-60 5 5.9561-70 6 7.1471-80 6 7.1481-90 4 4.76

91-100 11 13.10

- 19 -

Figure 19 suggests that the channel gradient peaks under certain descriptors but this is more likely to be down to the surveyor’s judgement in choosing a single rather than mixed category to describe the slope. For each it was a case of looking at the variation within the aggregate length and deciding whether it was sufficiently uniform to place under a single heading or to use more than one. Seventy-one of the seventy-seven lengths are more or less equally split between slight, moderate and steep. Only very few are either flat or very steep. This means that the majority of slopes fall within the 1% - 12% gradient range. It is presumed that a width of 0 metres (Figure 20) means there is no discernible channel for two examples. Most fall within the range 0.5m to 1.5m, though one was almost 3.5m wide. The mean width was 1.03m and this figure shows that the flow of water, likely to be of high volume after heavy rainfall, is concentrated within a relatively narrow channel to become a significant erosive force. The confinement of the flow also needs to take account in that it would expand laterally within the confines of the gulley slopes on either side and most of these are sloping rather than vertical (see below). Aggregated gulley lengths in Figure 21 show that the bare peat cover classes are evenly distributed. It means the cumulative length of channel with no bare peat is similar to that with 100% bare peat, as are all the cover classes in between. There appears to be more clustering when it comes to individual plant species (Figure 22). Figure 22 Frequency of conspicuous plants along the channel as % within six cover classes

Common heather was found in around half of the channel lengths, mostly between 20% to 80% cover. Wavy hair-grass (which may also include Sheep’s Fescue Festuca ovina) was found in three-quarters of the channel lengths with peak frequency in the lowest range at 1% - 20% cover. The other species more typical of dry heath, such as Bilbery and Crowberry were only found in a small proportion of the channel lengths, but Crowberry was typically present at high cover in its few occurrences. Of those species more typical of wetter situations, Purple moor-grass was particularly scarce and Sphagnum species restricted to a single record. While Common cotton-sedge was found in around 85% of the samples, its cover was in the 1% - 20% range for over half of them and it did not reach 100% cover for any of the aggregated channel lengths. Hare’s tail cotton-sedge was absent from nearly 60% of the channels but where present in the remainder its peak frequency was at a cover of 41% - 60%.

absent (% of records) 1-20% 21-40% 41-60% 61-80% 81-100%

Calluna vulgaris Common heather, Ling 46.75 7.79 11.69 15.58 18.18 0.00Deschampsia flexuosa Wavy hair-grass 24.68 32.47 29.87 9.09 2.60 1.30Vaccinium myrtillus Bilberry 98.70 0.00 0.00 0.00 1.30 0.00Empetrum nigrum Crowberry 93.51 0.00 0.00 0.00 5.19 1.30Molinia caerulea Purple moor-grass 88.31 5.19 2.60 0.00 2.60 1.30Eriophorum angustifolium Common cotton-grass 14.29 51.95 23.38 7.79 2.60 0.00Eriophorum vaginatum Hare's tail cotton-grass 57.14 2.60 11.69 22.08 5.19 1.30Sphagnum Undetermined species 98.70 0.00 1.30 0.00 0.00 0.00

Plant species

% of gulley lengths in % cover class

- 20 -

Any plant cover along the channel provides a degree of improved stability against further peat erosion but the proportion with no cover at all was still around 13% of the aggregated sampled lengths. 10. ‘All Series’ physical gulley attributes and the vegetation cover: the sides Figure 23 shows the side slopes as given in Figure 18 but also expressed as a percentage of the total number of observations. This levels out the apparently large numbers of samples arising from the doubling up caused by the maximum and minimum style of recording the range of slopes in some of the aggregated lengths.

Figure 23 Number of aggregated lengths in each slope class expressed as totals and as a percentage.

Figure 24 Number of aggregated lengths of gulley sides in each slope gradient class. The large number of items arises from ‘doubling up’ to compensate for the ‘range’ method of recording many of the lengths.

range in degrees

range mean as

slope in %0-9 7.86 0 0.00

10-19 25.83 16 5.3320-29 45.66 30 10.0030-39 68.96 40 13.3340-49 98.04 97 32.3350-59 140.25 29 9.6760-69 209.64 13 4.3370-79 361.02 21 7.0080-89 1041.67 25 8.33

90 vertical 29 9.67

slope

total % of sum total

- 21 -

The Figures show that the most frequent slope gradient (98.04%) is around 45o and the most frequent depth of erosion is 1.0 – 1.09 metres. The range is wide, with about 10% of lengths having no side slope and another 10% being vertical at 90o. The eroded depth also covers a wide range from 0.30 - 0.39m to 2.60 – 2.69m. There is a second isolated peak in Figure 24 with 25 measurements in the range 2.00 – 2.09m, deeper than the height of a relatively tall person.

Figure 25 Proportion of aggregated gulley side lengths in each bare peat class, the classes being the positions on the slope such as top or bottom.

Figure 26 Frequency of conspicuous plants on the gulley sides as % within six cover classes

Slightly more than 80% of aggregated lengths had an area of bare peat and this most commonly (27.15% with another equivocal 15.23%) affected the whole of the slope. The remainder of those with bare peat were split between top and bottom of the slope with very few just midway down. Common heather was more ubiquitous on the slopes than along the channel and was absent only in around 5% of cases. Although most common at the lower cover ranges some were also present in the 81-100% cover class. As with the channel, Wavy hair-grass was commonest at low cover. Other dry heath species occurred conversely, with Bell heather, Cross-leaved heath, Bilberry and Crowberry occurring in the highest cover ranges though doing so at very low frequency; although ‘rare’, where present, they achieved high cover. Unlike its performance in the channels, Common cotton-sedge reached the highest cover range in a small number of instances on the gulley slopes though it far more frequently occurred at lower cover. Similarly to what was found in the channels, Hare’s tail cotton-sedge occurred in only a quarter of the lengths but achieved high cover where it had become established. No Sphagnum mosses were found on the gulley sides.

absent 1-20% 21-40% 41-60% 61-80% 81-100%

Calluna vulgaris Common heather, Ling 5.33 50.67 26.00 12.67 4.67 0.67Deschampsia flexuosa Wavy hair-grass 9.33 23.33 36.00 25.33 6.00 0.00Vaccinium myrtillus Bilberry 94.67 0.00 0.00 0.67 2.00 2.67Erica cinerea Bell heather 99.33 0.00 0.00 0.00 0.00 0.67Erica tetralix Cross-leaved heath 98.66 0.00 0.00 0.00 0.67 0.67Empetrum nigrum Crowberry 54.67 0.67 4.00 16.67 17.33 6.67Eriophorum angustifolium Common cotton-grass 7.33 25.33 26.00 30.00 8.67 2.67Eriophorum vaginatum Hare's tail cotton-grass 74.67 0.00 2.00 5.33 13.33 4.67

Plant species

% of gulley lengths in % cover class

Bare peat (All, Top, Middle, Bottom)

Number of gulley lengths in each

class

Expressed as % of

total

none 27 17.88(T) 13 8.61T 20 13.25M 1 0.66(B) 6 3.97B 20 13.25(A) 23 15.23A 41 27.15

- 22 -

11. Condition of dams over all series The dam attributes are summarised in Figure 27.

Figure 27 Summarised dam condition characteristics for all dam series

The damaged and intact categories refer to structural integrity and do not take account of whether they are holding water or if the channel around them is affected by side leaks and eroded pits. As 73.5% are described as intact and only 38% are holding water it means that even dams deemed to be intact may be leaky, even though the proportion of reported leaks is low. Although a downslope pit is eroded by water overspilling the dam in 25% of cases, 89% are described as trapping silt. It is not possible to comment of the dynamics of silt movement simply by recording its presence. For example, silt may gradually move down the series of dams, being deposited briefly before being eroded again. Channel bareness suggests a degree of disturbance that prevents plant establishment and supports a more dynamic concept in which the silt is sporadically on the move. 12. Discussion and conclusions including those from K Quantrell 2013 Bog restoration principles As set out in Section 2, the National Trust’s assessment as presented by K Quantrell in 2013 was based on the Moorland Management Plan 2006-2016. It poses very practical questions predicated on the belief that controlling the flow of water in the existing gullies is the key to a non-erosive water management regime within which the blanket mire condition can improve. This report some six years later provides an opportunity to broaden the scope of the discussion and to consider whether installing ‘watertight’ dams in the existing gullies is the preferred or indeed the only approach. Experience of controlling surface water flow on peat bogs is not restricted to those in the uplands. Although the focus of restoration work on lowland bogs has been the raising of the water table in the peat, thought has also been given to the surface flow, not least, to address its erosive power. Destructive forces such as frost-heave, exacerbated by wind and surface run-off, erode dry peat. Saturated peat arising from successful management such as damming and bunding becomes potentially mobile and vulnerable to mass movement (bog bursts) and is also eroded by strong channelled flow as is seen on Buckstones. Strategies for bog restoration in the lowlands are based on two important theoretical principles. The consequence of thinking about a lowland bog as a gently domed structure with a groundwater mound is that the water table has to be maintained within a few centimetres of the surface, even in

number percentTotal inc top and bottom 457Damaged 121 26.48Intact 336 73.52Side or bottom leak 11 2.41Downslope pit 115 25.16Holding water 175 38.29Trapping silt >12cm deep 408 89.28

Attribute Dams

- 23 -

the driest months. This was developed from the original concept (the diplotelmic mire) of Ivanov by workers such as Ingram and Bragg (the groundwater mound) and these underpinned the UK’s site conservation and management strategy for many years through guidance published by the Joint Nature Conservation Committee (JNCC). It led to the development of damming and bunding techniques in much the same way as is now used on blanket mire. By contrast, an EU-funded project known as the Dutch–Irish Raised Bog Study published its findings in 2002 in which the concept of acrotelm capacity is described. Here, not only is the water level in the peat important in the establishment of a Sphagnum-rich plant community, but also the position of the surface-water flow-paths. The density of Sphagnum development was found to be linked to the measured flux of surface water over that part of the bog surface. While all this may seem somewhat esoteric it is ideally the case that academically-based concepts underpin management practice, even if the logical links between them have sometimes become obscured. The concept of acrotelm capacity described in the Dutch-Irish Raised Bog Study may provide a new starting point for thinking about the management of surface water flow on blanket mire. Rather than allowing all the excess surface water to flush away down gullies and cause destructive erosion, ways of spreading it out over the surface, dissipating its erosive energy and nurturing the growth of Sphagnum mosses are discussed. The NT management plan. Three practical questions were asked by the National Trust: a) Are the dams holding water? Out of the 457 dams monitored, 175 (38%) of them were found to be holding water. The number of dams holding water on each of the gullies varied from only 4% (on gully C) to 96% (on gully R), with on average 44% of the dams on any particular gully successfully holding water. b) Are the dams retaining peat? Out of the 457 dams monitored, 408 (89%) of them were found to be trapping silt >12cm deep. With this varying from 63% – 100% dependent on the gully. c) Are the dams retaining structural integrity over their expected operational life? Out of the 457 dams monitored, 338 (74%) of them were found to be still intact in 2011. The number on each of the gullies varied from only 0% (on gully Q) to 100% (on gullies I,L,N & P), with on average 73% of the dams on any particular gully still being structurally intact after around 5/6 years of installation. Their expected operational life has not been defined and this is a prerequisite of deeming success or failure. It is not within the remit of the Survey Group to decide whether two-thirds of the dams being incapable of holding water after 5/6 years is acceptable to the National Trust. If the aim is to maintain the functionality of all the dams it becomes a very heavy management commitment. On top of this there is very little evidence that the holding back of surface water on the relatively few occasions when there is surface flow can lead to the healing and gradual infilling of the gullies. As was apparent from the detailed study of Series B, it is possible to relate success criteria to attributes such as slope gradient, peat thickness and position in the series. Information collected beyond Series B was not sufficiently detailed to allow reliable analysis. The work to enable it could be done but it would be extremely time-consuming and would be better taken on by a paid

- 24 -

consultancy. The decision to do this rests with the National Trust who will balance the benefits of paying for a stepwise knowledge-based approach against arguably optimistic professional judgements. However, before committing large amounts of time and money to frequent dam repairs it may yield dividends to consider the merits of an alternative approach, such as one based on dissipating the surface flow and keeping it out of the gulleys. The ability of the dams to retain peat is more encouraging with 89% of the dams monitored found to be trapping peat >12cm deep (the figure of depth accumulation being the marker used previously by Moors for the Future). However, there is no evidence that the silt present at the time of the survey is stable and the lack of vegetation cover along many of the channels suggests that it is not. The ideal conceptual model would be that the dam traps silt which in turn supports vegetation such as Common cotton-sedge and then traps more silt but there is currently (2011) very little evidence of it happening. The 2013 review of the information raises several questions about, for example, what proportion of dams remaining intact after 5/6 years is acceptable and what sort of situation is suitable for such damming. This splits into a discussion about different types of dam and whether the underlying concept of damming gullies is viable, though the wider principle was not discussed in 2013. It is possible to envisage different designs of dams. For example, they may be constructed by stone rubble infill or by getting willows to grow in the channel. None of these approaches has yet been shown to arrest any further erosion and build up the gulley with deposited peat and robust vegetation, though stone dams used on nearby Dovestones by the RSPB looks promising. Doing this successfully cannot be ruled out but the forces involved can be formidable and the peat forming the surround of any such structure has no cohesion. It is a loose array of partially-decomposed plant material and is only bound together at the surface where living plant roots may bind it. Buckstones has a large number of parallel deeply-eroded channels for its surface area and there has been no assessment of why this is so. Has the peat surface become so bituminised by successive fires that only a very small proportion of the atmospheric water is able to infiltrate? The damage in gullies suggests the flow is sporadic and of high volume; the degree of slope ensures that it has great erosive power. Observations from research on peat pipes in Moors for the Future suggest there is a flow of water between the peat base and the underlying mineral strata. This is bound to be a destabilising feature and may form cavities that collapse and join up to form more gulleys. It was noted at the time of the dam surveys that the peat has deep fissures at right-angles to the slope and this may indicate a gradual migration of peat down the slope, lubricated by water at the peat:mineral interface. At the very least the splits allow the ingress of surface water that can erode caverns and form more gulleys. The geology as apparent from the 1:50,000 scale BGS map does not reveal any heterogeneity of structure that might help in understanding why some dams are so easily undercut by the flow. Where visible the mineral substratum appears to be from weathered gritstone with a wide range of particle size from small rocks to clay-sized grains resulting in a very hard surface. The bottom plank of each dam would need to be embedded in this substratum if leaks were to be avoided, but the act of embedding would loosen the stratum and make it more susceptible to erosion. Coupled with the uncohesive peat abutting the sides it may not be possible to install watertight wooden dams on Buckstones.

- 25 -

Overall, the prognosis for successful water control on Buckstones is bleak. Rather than invest in periodic dam maintenance the money may be better spent of a full hydrological assessment as a basis for a hard engineering solution. The spreadsheets given in the Annexes provide a baseline that can be used for monitoring the condition of the dams and gulleys in the future. 13. References Ingram, H.A.P. & Bragg, O.M. 1984. The diplotelmic mire: some hydrological consequences reviewed. Proceedings of the 7th International Peat Conference, Dublin, June 1984. Irish National Peat Committee for the International Peat Society, 1, 220-234. Ivanov, K.E. 1981. Water movement in mirelands. Academic Press, London. Translated by A Thompson and H.A.P. Ingram. Schouten, M.G.C. (Ed). 2002. Conservation and restoration of raised bogs; geological, hydrological and ecological studies. ISBN 0-7557-1559-4. Government Publications Sales Office, Sun Alliance House, Molesworth Street, Dublin 2. Waters, C.N., Chisholm, J.I., Hough, E. & Evans, D.J. 2012. Geology of the Glossop District – a brief explanation of the geological map. Sheet Explanation of the British Geological Survey. 1:50 000 Sheet 86 Glossop (England and Wales).

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Annex 1 Full spreadsheets of information collected for Series B

Second half of spreadsheet is on next page

dam number 60 59 58 57 56 55 54 53 52 51 50 49 48 47 46 45 44 43 42 41 40 39 38 37 36 35 34 33 32 31 30 29 28 27 26 25 24 23 22date 28-3-11 28-3-11 28-3-11 28-3-11 28-3-11 28-3-11 28-3-11 28-3-11 28-3-11 23-3-11 23-3-11 23-3-11 23-3-11 23-3-11 23-3-11 23-3-11 23-3-11 23-3-11 23-3-11 23-3-11 30-3-11 30-3-11 30-3-11 30-3-11 30-3-11 30-3-11 6-4-11 6-4-11 6-4-11 6-4-11 6-4-11 6-4-11 6-4-11 6-4-11 6-4-11 6-4-11 6-4-11 6-4-11 6-4-11recorder RM RM RM RM RM RM RM RM RM RM/G/M RM/G/M RM/G/M RM/G/M RM/G/M RM/G/M RM/G/M RM/G/M RM/G/M RM/G/M RM/G/M NP/RM NP/RM NP/RM NP/RM NP/RM NP/RM RM RM RM NP NP NP NP NP NP NP NP NP NPphoto refweather: V dry, average, V wet D D D D D D D D D AVG AVG AVG AVG AVG AVG AVG AVG AVG AVG AVG D D D D D D wet wet wet wet wet wet wet wet wet wet wetGPS point 180 182/3 185/6 188-90 192 193 195/7 199/200 162 164 166 168 170 172 174 176 178 179 236 237 238 239 240 241 274 275 276 277 278 279 280 281 282 283 284 285 286eastingnorthing

construction datedam type (W, HB, S, Other) W W W W W W W W W W W W W W W W W W W W W W W W W W W W W W W W W W W W Wwater marks on planks Y/N N N N n n n N N N N N N N N N N N N N N N N N N N N Y Y N N Ndistance sill to HWM - 0.2 0.07

ConditionIs dam holding water? Y/N ? ? N N N N Y N ? ? N ? N ? N ? ? N ? ? ? Y Y Y Y Y Y Y (Y) Y Y Y Y Y Y Y Y Y YDoes water leak Under or Around the dam? N U U/A U U Y U U U N N N N U N U N N U U A N (U) N N N N Through A A T N N AU A A A A AIs dam trapping sediment? Y/N N Y N Y Y Y Y N Y Y Y Y Y Y Y Y Y Y Y Y Y Y Y Y Y Y Y Y Y Y Y Y Y Y Y Y Y Y Y

How far back does water extend from the dam (m)? - peatpeat/ sand

peat peat n 0.16 n n n nbare peat

bare peat

bare peat

bare peat

bare peat

bare peat

bare peat

bare peat

bare peat

bare peat

bare peat

peat/ veg

peat/ veg

3.8 1.8 2.4 2.8 2.5 pools pools 2.8 1.9 2.8

pit depth 0.45 0.35 0.2 0.3 0.15 0.35 0.25 0.25 0.15 0.2 0.35 0.2 0.6 0.2 0.2 0.35 0.1 0.15 0.14 0.13 0.12 0.22 0.4pit length 0.57 0.92 1.5 0.4 0.5 0.8 0.4 0.2 0.35 0.3 0.5 0.6 0.85 0.8 0.65 0.6 0.65 0.14 1.1 1 0.7 1.2 0.7Is dam intact, disintegrating, rotting, eroding? I U U V E I I E E I I I I E I E I I E E E I (E) I I I I I D E I I I E E E E E EIs maintenance required (Y/N)? N Y Y Y Y N N Y Y N Y N N Y N Y N N Y Y Y N (Y) N N N N Y Y Y Y N N Y Y Y Y Y Y

sill elevation (level, as calculated from benchmark) 10.059 10.344 10.656 10.997 11.197 11.785 12.079 12.399 12.644 12.994 13.544 13.664 13.784 14.074 14.514 14.754 14.894 15.074 15.194 15.314 15.464 15.614 15.704 15.844 16.054 16.174 16.354 16.624 16.894 17.044 17.324 17.514 17.704 17.844 17.904 18.054 18.264 18.4648cm w

water surface upstream relative to benchmark, m N 10.797 11.147 11.485 11.599 12.149 16.014 15.834 15.914 16.384 16.514 16.624 17.154 17.514 17.664 17.804 17.904 18.044 18.254 18.454water surface downstream relative to benchmark, m 10.447 10.817 11.735 11.599 11.869 15.824 16.044 16.334 16.494 16.654 16.914 17.254 17.514 17.704 17.834 17.904 18.084 18.244 18.434

peat surface relative to benchmark upstream 9.008 9.335 9.775 10.502 10.737 10.897 11.205 11.550 11.949 12.514 13.034 13.534 13.674 13.464 13.984 14.394 14.664 14.794 15.074 15.124 15.264 15.374 15.324 15.404 15.614 15.734 15.714 16.134 16.154 16.464 16.734 17.074 17.404 17.644 17.794 17.854 18.024 18.204 18.364peat surface relative to benchmark downstream 8.978 9.009 9.55 10.113 10.445 10.777 11.435 11.540 11.949 12.344 12.684 13.074 13.144 13.194 13.484 13.944 14.254 14.364 14.664 14.574 14.844 15.014 15.104 15.354 15.464 15.734 15.674 15.964 16.034 16.334 16.624 16.884 17.244 17.494 17.584 17.674 17.744 17.934 18.124 18.434peat depth above dam m 1.11 0.52 0.34 0.47 0.45 0.74 0.67 0.68 0.68 0.62 1.42 1.12 0.82 0.33 0.7 0.95 0.82 0.74 0.85 0.9 0.8 0.79 0.61 0.71 0.85 0.84 0.66 1.04 0.86 1.08 1.1 1.22 1.24 1.45 1.51 1.5 1.44 1.35 1.56peat depth below dam m 1.11 0.11 0.26 0.39 0.1 0.39 0.34 0.55 0.43 0.73 0.95 0.75 0.42 0.28 0.22 0.54 0.5 0.63 0.5 0.73 0.42 0.46 0.51 0.64 0.8 0.74 0.48 0.8 0.57 0.9 1.08 1.01 1.12 1.33 1.29 1.28 1.02 1.44 1.35

How far upstream does open water extend? Soft peat? peat peat peat peat 0.16 3.8 1.8 2.4 2.8 2.5 pools pools 2.8 1.9 2.8floor/channel shape curve kink straight straight straight. straight straight kink straight curve straight curved straight curved straight S straight curved

Gulley measurementsGulley floor elevation relative to BM above lower dam 9.008 9.335 9.775 10.502 10.737 10.897 11.205 11.55 11.949 12.514 13.034 13.534 13.674 13.464 13.984 14.394 14.664 14.794 15.074 15.124 15.264 15.374 15.324 15.404 15.614 15.734 15.714 16.134 16.154 16.464 16.734 17.074 17.404 17.644 17.794 17.854 18.024 18.204 18.364Gulley floor elevation relative to BM below upper dam 8.917 9.55 10.113 10.445 10.785 11.435 11.54 11.84 12.344 12.684 13.074 13.144 13.194 13.484 13.944 14.254 14.364 14.664 14.574 14.844 15.014 15.104 15.354 15.464 15.734 15.674 15.964 16.034 16.334 16.624 16.884 17.244 17.494 17.584 17.674 17.744 17.934 18.124 18.434Distance between these two points 11.5 7 4.1 3.55 0.91 4.7 4.7 4.3 5.9 3.23 6.5 5.4 6 1.6 3.6 5.05 3.3 3.3 2.45 1.4 3.4 3.2 2.8 3.2 3.5 3.8 3.3 2.4 2.8 4.2 4.55 3.75 3.15 2.5 2.9 2.8 1.9 2.8 2.7Slope as distance/elevation change (formula) -126.37 32.56 12.13 -62.28 18.96 8.74 14.03 14.83 14.94 19.00 162.50 -13.85 -12.50 80.00 -90.00 -36.07 -11.00 -25.38 -4.90 -5.00 -13.60 -11.85 93.33 53.33 29.17 -63.33 13.20 -24.00 15.56 26.25 30.33 22.06 35.00 -41.67 -24.17 -25.45 -21.11 -35.00 38.57Slope as above but compensating for pit depth -126.37 10.53 12.13 -62.28 2.29 8.74 8.79 7.29 14.94 19.00 34.21 -135.00 -26.09 5.93 32.73 84.17 -11.00 15.00 -8.17 4.38 -68.00 -45.71 7.37 20.00 12.96 47.50 8.68 120.00 7.00 26.25 30.33 22.06 35.00 -41.67 -24.17 -25.45 -21.11 -35.00 5.74

At lower damDistance gulley top to base of slope 6.9 4.7 2.3 1.2 1.8 1.8 1.3 2.1 2.6 2.6 1.1 3.1 2.8 5 5 1.9 0.7 2.4 3.7 2.8 2 1.5 1.3 3.2 1.7 2.2 0.8 1.4 1.7 1.3 1.4 1.3 1 2.2 1.6 3.2 0.6 0.3 0.6Distance gulley top to other side of floor 8.6 6.4 3.2 2.5 2.8 2.8 2.3 2.5 3.2 3.2 2.2 4 4.3 6 6 2.7 2 3.8 4.9 3.7 3.2 2.6 1.9 3.9 2.8 3.4 1.8 3 3.2 2.1 3.25 2.1 1.8 4.3 4.6 7 6.1 4.1 2.7Distance gulley top to opposite gulley top 9.4 7.5 5.2 3.5 4.2 4.2 3.6 3.5 4.3 4.3 3.3 7 8 10.3 10.3 9 5 4.6 6.5 5.3 4.3 3.5 3.9 5.6 4.2 4.9 4.3 4.7 4.3 3.6 4.2 3.75 5 6.3 6.5 8.5 8.9 4.6 3.8Elevation top A 9.946 10.288 11.323 11.817 12.185 12.24 12.597 12.793 13.014 13.177 13.334 14.084 14.194 14.144 14.144 14.794 14.964 15.754 15.744 15.814 15.994 16.004 15.934 15.824 15.824 16.444 16.664 16.564 17.114 17.124 17.424 17.704 17.994 18.104 18.504 18.464 18.794 18.574 18.724Elevation floor 9.008 9.335 9.775 10.502 10.737 10.897 11.205 11.55 11.949 12.514 13.034 13.534 13.674 13.464 13.984 14.394 14.664 14.794 15.074 15.124 15.264 15.374 15.324 15.404 15.614 15.734 15.714 16.134 16.154 16.464 16.734 17.074 17.404 17.644 17.794 17.854 18.024 18.204 18.364Elevation top B 9.467 10.525 11.385 11.463 12.05 12.035 12.626 12.765 13.104 13.44 13.384 13.854 14.074 14.174 14.384 14.694 15.014 15.564 16.024 15.984 16.014 16.154 16.154 16.154 16.634 16.624 16.404 17.414 17.354 17.424 17.624 17.834 17.984 18.574 18.414 18.414 18.624 18.694 18.744Slope A 7.36 4.93 1.49 0.91 1.24 1.34 0.93 1.69 2.44 3.92 3.67 5.64 5.38 7.35 31.25 4.75 2.33 2.50 5.52 4.06 2.74 2.38 2.13 7.62 8.10 3.10 0.84 3.26 1.77 1.97 2.03 2.06 1.69 4.78 2.25 5.25 0.78 0.81 1.67Slope B 0.85 1.15 1.29 0.76 0.97 1.04 0.93 0.80 1.03 1.66 3.67 5.45 7.12 6.32 26.88 15.75 10.00 0.83 2.39 2.32 1.51 1.43 3.28 4.05 6.67 2.11 2.63 3.95 1.15 2.27 1.38 2.62 5.42 4.35 2.68 2.46 3.64 1.35 3.06

At mid-pointDistance gulley top to base of slope 6.1 3.3 2.3 1.5 1.8 1.5 1.8 1.9 2 1.8 3 2.7 2.4 2.4 8.7 0.9 2.1 3.2 3.7 2.8 2.2 0.55 1.5 3.9 1.8 0.9 2 0.8 1.9 1.1 1 1.4 1.2 1.5 1.1 1.6 0.2 0.3Distance gulley top to other side of floor 7.7 4.8 3.2 2.4 2.8 2.3 2.3 2.5 2.7 2.6 4 4 4.2 4.2 9.8 1.9 3.3 4.2 4.9 3.7 3.3 1.2 1.9 4.5 2.5 1.6 2.7 2.4 3.4 2 2 2.3 2.4 4.1 5.08 6.5 3.75 4Distance gulley top to opposite gulley top 9 5.8 5.2 3.4 4.2 3.8 4.3 4 3.2 3.3 6 7.3 7.6 7.6 10.7 7.5 6.2 5.8 6.5 5.3 4.2 2.9 3.8 5.1 4.1 3.6 4.9 3.6 4.4 3.6 4 5 4.6 6.1 7.2 7.5 4.6 4.5Elevation top A 10.003 10.690 11.566 12.093 12.145 12.379 12.501 12.784 12.894 13.304 13.944 13.914 14.342 14.144 14.334 14.874 15.254 15.744 15.744 15.954 15.984 15.018 15.984 15.824 16.354 16.584 16.564 16.914 17.034 17.344 17.554 17.794 18.104 18.194 18.624 18.754 18.694 18.794Elevation floor 9.22 9.337 9.672 11.072 10.327 11.124 11.337 11.562 12.054 12.564 12.974 13.414 13.414 13.444 13.944 14.304 14.564 14.714 14.964 14.854 15.144 14.236 15.334 15.434 15.734 15.764 15.954 16.264 16.334 16.574 16.814 17.144 17.484 17.624 17.824 17.864 18.024 18.224Elevation top B 10.003 10.69 11.566 12.093 12.145 12.379 12.501 12.784 13.024 13.054 13.444 13.764 14.234 14.324 14.724 14.694 15.084 15.694 16.054 15.984 16.274 16.154 16.154 16.044 16.604 16.884 17.294 17.354 17.404 17.544 18.004 17.874 18.304 18.414 18.414 18.484 18.664 18.794Slope A 7.79 2.44 1.21 1.47 0.99 1.20 1.55 1.55 2.38 2.43 3.09 5.40 2.59 3.43 22.31 1.58 3.04 3.11 4.74 2.55 2.62 0.70 2.31 10.00 2.90 1.10 3.28 1.23 2.71 1.43 1.35 2.15 1.94 2.63 1.38 1.80 0.30 0.53Slope B 1.66 0.74 1.06 0.98 0.77 1.20 1.72 1.23 0.60 0.95 2.06 6.60 3.66 4.86 2.31 9.82 4.20 1.55 2.05 1.45 1.07 2.17 2.92 1.54 2.58 2.44 3.61 1.85 1.43 2.08 2.70 4.15 3.55 3.51 2.65 1.12 1.27 0.88water surface elevation 15.864

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dam number 60 59 58 57 56 55 54 53 52 51 50 49 48 47 46 45 44 43 42 41 40 39 38 37 36 35 34 33 32 31 30 29 28 27 26 25 24 23 22

Vegetation in channel upstream of the damGulley top A (within 10m)Bare peat % 10 50 5 0 0 3 5 5 0 5 20 20 50 100 5 30 0 40 40 40 20 0 0 0 0 0 0 0 10 5 30 15 5 0 20 0 5 5 5Bare mineral %Vegetation % 90 50 95 100 100 97 95 95 100 95 80 80 50 0 95 70 100 60 60 60 80 100 100 100 100 100 100 100 90 100 70 85 95 100 80 100 95 95 95Common cotton grass % of veg 1 2 5 3 10 15 10 10 5 15 15 5 20 5 5 5 10 30 40 35 25 10 15 15 15 30 5 10 30 5 5 5 2 5 2 2Hares tail cotton grass 15 85 40 55 35 30 35 15 20 5 30 80 50 40 20 5 10 10 10 2 15 5 10 5 2 2 5 20 20 10 15 10 20 60 75 80 80Heather (Ling) 5 10 40 35 35 30 45 30 30 60 30 20 30 20 50 80 75 75 70 65 55 45 65 35 35 70 65 25 50 30 15 5 5 5 5Bilberry 45 5 5 5 5 5 15Crowberry 1 7 15 10 20 20 40 35 20 10 5 10 + 5 5 10 20 10 10 15 10 35 5 15 5 30 10 10 10 10non-Sphagnum moss 30 5 10 30 5 20 15 10 5 10 10 20 5 10 2 2 3 5 5 20 20 15 10 5 10 5 5 2 2 25 10 25 10 10 10 5Sphagnum mossLichen 5 3 10 10 5 + 5 2 2 2 2 2 5 15 10 15 5 2 2 2 10 10 10 2 5 5 5 2 2Wavy hair-grass/Sheep's fescue 5 3 3 5 10 2 5 30 35 5 15 10 20 10 5 15 35 60 30 15 10 10Molinia 3 5 5 2Gulley side ABare peat % 5 98 95 100 100 50 15 15 60 10 15 50 80 100 20 50 30 97 97 100 5 80 5 5 0 50 15 85 70 60 0 60 95 40 95 95 95 95Bare mineral %Vegetation % 95 2 5 0 50 85 85 40 90 85 50 20 0 80 50 70 3 3 95 20 95 95 100 50 85 15 30 40 100 100 40 5 60 5 5 5 5Common cotton grass % of veg 2 50 95 10 15 40 30 5 40 50 80 5 60 80 75 95 45 80 55 15 95 45 10 70 70 5 90 80 95 50 90 100 95 95Hares tail cotton grass 15 3 75 35 10 30 40 10 30 70 70 45 10 2 5 90 25 15 15 15 10 5 5Heather (Ling) 10 2 10 45 20 15 40 40 20 30 45 20 20 25 2 55 20 40 40 35 5 15 5 10Bilberry 5Crowberry 50 10 5 2 5non-Sphagnum moss 20 2 10 15 20 30 5 10 5 10 5 15 10 10 40 10 15 20 2 2 2 2 5 2 5 5Sphagnum mossLichen 5 + 2 + 20 + 5 5 2 2 2 2Wavy hair-grass/Sheep's fescue 10 15 5 20 10 5 60 10 5 5 25 5Gulley floorBare peat % 0 98 50 99 100 75 35 50 20 90 90 100 100 100 80 100 100 90 100 100 100 80 95 20 10 55 60 95 95 55 50 10 30 95 80 100 95 95 95Bare mineral % 47Vegetation % 100 2 3 1 0 25 65 50 80 10 10 0 0 0 20 0 10 20 5 80 90 45 40 5 5 45 50 90 70 5 20 0 5 5 5Common cotton grass % of veg 55 4 100 10 5 30 85 100 100 + 30 100 95 100 100 90 100 100 70 100 100 100 95 95 100 100Hares tail cotton grass 5 95 85 50 60 15 55 30 5 5 100Heather (Ling) 5 3 45 15 100BilberryCrowberrynon-Sphagnum moss 1 2 10Sphagnum mossLichenWavy hair-grass/Sheep's fescue 25 1 10 100 5

Channel noneBare peat %Bare mineral %Vegetation %Common cotton grass % of vegHares tail cotton grassHeather (Ling)BilberryCrowberrynon-Sphagnum mossSphagnum mossLichen

Gulley side BBare peat % 10 40 50 50 30 5 10 5 10 10 5 0 15 5 20 5 20 75 75 95 45 30 85 15 25 5 20 90 95 25 5 5 45 95 45 95 95 98 95Bare mineral %Vegetation % 90 60 50 50 70 95 90 95 90 90 95 100 85 95 80 95 80 25 25 5 55 70 15 85 75 95 80 10 5 75 95 95 55 5 55 5 5 2 5Common cotton grass % of veg 10 93 10 10 15 3 35 10 20 18 15 15 10 7 40 20 65 100 50 100 95 90 35 25 45 85 45 95 100 100 80 35 90 85 30 95 95 100 75Hares tail cotton grass 45 2 40 65 35 40 20 30 45 18 20 5 20 7 20 5 20 35 2 5 5 5 10 3 25Heather (Ling) 10 40 25 50 35 40 55 25 50 60 60 20 80 20 70 15 50 3 30 50 30 10 40BilberryCrowberry 2 + 5non-Sphagnum moss 30 5 20 5 10 20 25 10 10 10 10 20 50 7 20 5 5 10 2 60 10 45 20 10 15 2 50 5Sphagnum mossLichen 5 2 + 2 2 2 15 2 5 2 2 5Wavy hair-grass/Sheep's fescue 20 15 15 10 5 10 5 30 10 5 10 2Gulley top BBare peat % 0 5 0 5 5 10 0 0 0 0 0 0 0 0 0 0 0 5 5 20 0 5 5 0 5 0 2 5 10 0 15 0 10 10 20 10 40 0 10Bare mineral %Vegetation % 100 95 100 95 95 90 100 100 100 100 100 100 100 100 100 100 100 95 95 80 100 95 95 95 100 98 95 90 100 85 100 90 90 80 90 60 100 90Common cotton grass % of veg 2 10 5 5 3 5 55 70 15 15 25 + 5 5 5 15 10 5 5 5 20 10 5 5 5 5 5 5 10 5 20 10 10 5 5 5 30 15 20Hares tail cotton grass 45 65 80 40 30 30 20 5 10 15 30 10 15 15 5 15 + 10 20 15 10 10 10 20 15 20 20 55 30 25 20 20 20 25 35 50 50 45 35Heather (Ling) 10 15 10 35 40 40 20 15 30 30 40 80 80 80 80 60 80 80 75 70 70 65 70 45 30 40 40 25 35 10 20 20 10 10 20 15 10 5 10Bilberry 2 3 5 5 15 15 10 10Crowberry 5 10 5 + + + 5 + 2 10 5 10 10 15 15 60 30 40 55 30 30 20 5 10 20non-Sphagnum moss 35 10 20 30 40 25 30 10 40 30 5 10 + + + 10 10 5 5 10 20 60 45 15 45 10 5 5 5 15 2 5 2 20 20 10 10 10 15Sphagnum mossLichen + + + + 2 3 5 5 25 40 10 15 15 5 5 2 2 10 10 10 15 2 2 2 2Wavy hair-grass/Sheep's fescue 10 3 25 20 20 10 10 2 2 2 15 5 20 5 10 5 20 5 10 15 10 15 10 5

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Annex 2 Summary spreadsheet for all the series of dams The spreadsheets contain information for aggregated sections of each series as indicated by dam numbers ‘from….to’. Traffic light colours have been used where it is possible to judge whether an attribute has a range from good to bad in terms of dam and gulley function.

Series/date:from 1 3 9 16 309 313 22 37 47 49 58 98 97 94 92 91 85 82 81 70 69 66 65

to 3 9 16 21 312 320 37 47 49 58 60 97 94 92 91 85 82 81 70 69 66 65 61Dams* total inc top and bottom 3 7 8 6 4 7 16 11 3 10 3 2 4 3 2 7 4 12 2 4 2 5Dams* intact 3 7 6 4 4 4 8 4 0 2 1 1 3 3 1 7 4 12 2 4 2 4Dams* with side or bottom leak 0 0 1B1S 2B 0 3S 1B7S 7B 3B1S 8B4S 2B1S 1 2 1 1 1Dams* with downslope pit 0 0 2 0 0 0 11 11 3 2 1 5 11 5Dams* holding water 3 2 6 0 2 6 14 0 0 4 0 1 1Dams* trapping silt >12cm deep 3 7 8 6 4 5 16 11 3 9 2 1 4 3 2 7 4 12 2 4 2 5Gulley bottomSlope (Steep, Moderate, Slight, Flat) Sl M St V.St Sl M M M/St M St Sl ST M ST SL ST M SL SL SL M SL MAverage width m. 1.2 0.9-1.4 0.9 1.1 0.8 1.5 0.6-1.5 1 1 0.7 2 1.4 1 0.9 1.4 1.2 0.6 1.7 0.5-1.0 1.3 1.1 0.9 0.9Gulley floor, % length bare 5 60 60 90 80 10 30 98 98 25 40 0 20 0 0 90 0 ? 100 0 70 0 50Calluna vulgaris 3 4 4 2 3 4 0 1 0 0 4 0 0 1 1 0 1 0 0 3 0 0 0Deschampsia flexuosa 1 2 2 1 2 2 2 0 0 3 2 0 1 2 1 1 3 0 0 2 0 0 0Eriophorum angustifolium 2 1 1 3 1 1 1 2 1 2 1 1 1 0 1 1 2 0 0 0 0 0 0Eriophorum vaginatum 4 3 3 0 0 3 3 3 0 1 3 0 0 0 0 1 4 0 0 0 0 0 0Molinia caerulea 0 0 0 0 0 0 0 0 0 0 0 0 1 2 1 1 0 0 0 0 0 0 0Sphagnum spp present 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0Other 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0Gulley sides (1=E or N; 2=W or S ) 1. Slope approx degrees (90=vert) 15-40 30 20-45 55 20 40-70 35 50-90 30 65-90 25-90 90 90 45 90 30 90 50 50 50 25-901. Depth range (m) 0.5-2.5 1.3 0.6-1.4 0.6-1.2 0.4 1.0-1.4 1.1-1.3 1.2-1.7 2 2 1-2.2 0.4-1.5 0.4-1.5 1.2 1.5 1 0.3-1 0.5 1 1 0.41. Bare peat (All, Top, Bottom) (A) (A) (A) A (A) A A (B) (A) B (T) T T (T) A 0 (A) 0 0 0 (T)1. Calluna vulgaris 1 2 1 2 3 3 2 1 1 1 1 1 1 3 1 1 1 3 2 2 21. Deschampsia flexuosa 3 3 3 3 2 1 3 0 3 2 2 0 0 2 0 2 0 2 4 4 41. Empetrum nigrum 0 4 4 0 0 0 5 0 4 4 0 0 0 0 0 0 0 0 3 3 31. Eriophorum angustifolium 2 1 2 1 1 2 1 2 2 3 3 0 0 1 0 3 0 1 1 1 11. Eriophorum vaginatum 0 0 0 0 0 0 4 3 0 0 0 0 0 4 0 4 0 0 0 0 01. Other 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 02. Slope approx degrees (90=vert) 15-40 20-40 15-70 45-85 20 40 35 30-50 40 65 45-70 90 90 45 90 30 90 50 50 50 25-902. Depth range (m) 0.5-1.4 0.5-1.0 0.4-1.3 0.9-1.2 0.4 1.5 0.8-1.2 1.2-1.5 2 2-2.3 1.1-2.5 2 2 1.2 1.5 1 0.3-1 0.5 1 1 0.42. Bare peat (All, Top, Bottom) A A 0 A A A A A A (A) A T T (T) A (A) 0 0 0 (T)2. Calluna vulgaris 1 1 1 2 2 3 2 1 4 1 1 1 1 3 1 1 1 3 2 2 22. Deschampsia flexuosa 2 2 3 1 3 1 1 3 1 4 3 0 0 2 0 2 0 2 4 4 42. Empetrum nigrum 0 4 0 0 0 0 4 4 2 5 5 0 0 0 0 0 0 0 3 3 32. Eriophorum angustifolium 3 3 2 0 1 2 3 2 3 2 2 0 0 1 0 3 0 1 1 1 12. Eriophorum vaginatum 0 0 0 0 0 4 5 0 0 3 4 0 0 4 0 4 0 0 0 0 02. Other 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0

AA 21-9-11 Buckstones A, 28-9-11 B 25-9-11 C July 2011

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Series/date:from 104 103 135 134 131 127 124 116 111 109 136 140 152 156-9 228 241 245 255 259 264 270 272 274 280

to 103 99 134 131 127 124 116 111 109 105 140 152 156 222-228 241 245 254 259 264 270 271 274 280 288Dams* total inc top and bottom 2 5 2 4 4 4 9 6 3 5 5 13 5 12 12 5 10 5 6 7 2 3 7 9Dams* intact 2 3 1 2 3 3 7 3 3 5 3 12 0 10 8 5 3 5 6 6 1 3 7 9Dams* with side or bottom leak 0 2B 1B 2B 1B 1 2B 3B 0 0 2B 1B 5B 2B 4 0 7Binc2S 0 0 2B 1B 0 0 0Dams* with downslope pit 1 0 1 2 1 1 6 4 0 1 5 2 4+sand 8 rck 11 rck 0 5 rck 0 1 1 1 0 0 0Dams* holding water 0 1 1 3 2 0 0 0 0 2 12 0 0 1 5 0 4 0 0 0 2 5 0Dams* trapping silt >12cm deep 2 5 2 4 4 4 9 6 3 5 5 4 11 12 5 8 5 6 6 1 3 7 9Gulley bottomSlope (Steep, Moderate, Slight, Flat) ST SL SL ST ST SL M M M ST ST M M M SL F VST SL M M/S SL SL M STAverage width m. 0.9 0.4-2.1 1 1.2 0.9 1.5 0.7 0.6 2.2 1.1 1.5 1.1 0.7 0.7 0.7 2.1 0.5-1.5 0.5-1.3 0.4-1.1 0.2-1.2 0.4-1.2 0.5 0.8-1.1 0.4-0.9Gulley floor, % length bare 0 50 20 40 20 10 95 97 0 60 50 10 80 98 98 0 90 70 45 100 90 40 15 15Calluna vulgaris 2 0 0 3 4 4 0 0 3 0 0 0 2 0 0 0 2 4 0 0 3 3 4 2Deschampsia flexuosa 0 0 1 1 1 2 1 0 2 1 0 0 0 1 2 2 1 2 1 0 2 1 2 1Eriophorum angustifolium 1 1 2 2 3 1 2 1 1 2 1 1 1 2 1 1 0 1 2 1 1 2 1 3Eriophorum vaginatum 3 2 0 0 2 3 0 0 0 0 0 2 0 0 0 0 0 3 0 0 0 0 3 0Molinia caerulea 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 5 0 0 4 0 0 4Sphagnum spp present 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0Other 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 Emp 4 0 0 0 0 0Gulley sides (E or W; N or S) 1. Slope approx degrees (90=vert) 45 80 20 45 80 30 45 45-90 20-45 40 45 30-45 80 70-90 80 45 90 25-40 35-50 45 30-70 45 30-50 451. Depth range (m) 0.4-0.9 0.8-1.2 1.2 0.9-1.5 0.8-1.2 1.1-1.5 0.8-1.0 0.9-1.1 0.8-1.3 0.9-1.2 1-1.3 1-1.3 1.3-2.1 0.9-1.5 0.9-1.6 1.1 2-2.5 0.5-1.0 0.5-0.8 0.7-0.8 1.5 0.65 1 11. Bare peat (All, Top, Bottom) B 0 T B A/T/B 0 B B 0 M A T B B B T T&B (A) T A A A (T) (T)1. Calluna vulgaris 1 1 1 1 1 1 1 1 1 1 1 2 1 1 2 3 1 1 3 1 1 0 2 11. Deschampsia flexuosa 0 4 2 2 2 3 3 2 3 2 2 3 4 3 1 2 2 2 2 3 3 1 3 21. Empetrum nigrum 3 3 0 0 0 0 0 0 0 0 3 4 3 0 4 0 0 5 0 4 0 0 0 01. Eriophorum angustifolium 2 2 3 3 3 2 2 3 2 3 4 1 2 2 3 1 3 4 1 5 2 2 1 31. Eriophorum vaginatum 0 0 0 4 4 0 0 0 0 4 0 5 0 0 0 0 0 0 0 0 0 0 0 01. Other 4 E tet 0 0 5 0 0 0 0 0 0 0 0 0 0 0 0 0 3 0 2 0 0 0 02. Slope approx degrees (90=vert) 30-80 45-80 75 70 45 40 45 80 40 40 50 30-60 45-90 30-90 50-80 45-80 75-85 25-30 35-80 45 30-60 30-45 15-45 452. Depth range (m) 0.6-1.1 0.6-1.1 1.2 1.2-1.6 0.9-1.5 1-1.2 0.8-1.5 1-1.1 0.9-1.3 1.2-1.8 1.1-1.3 1.1-1.3 1.3-2.0 1.1-1.5 1.1-1.6 1-1.1 2.6 1.1 0.8 1.2 0.6 0.4-0.9 0.4-1.22. Bare peat (All, Top, Bottom) 0 0 B A/T T A B T 0 A T B B B T A (A) T 0 B A 0 A2. Calluna vulgaris 1 3 1 3 2 2 1 1 3 1 0 1 1 1 2 2 1 1 0 1 1 2 2 12. Deschampsia flexuosa 0 2 2 2 1 1 3 0 2 2 1 2 0 3 1 3 3 2 1 3 2 1 3 32. Empetrum nigrum 4 5 0 0 0 0 0 0 0 5 2 4 3 0 0 5 0 4 3 4 4 0 0 02. Eriophorum angustifolium 2 1 3 1 3 3 4 2 1 4 3 3 2 2 3 1 2 5 2 2 3 3 1 22. Eriophorum vaginatum 3 4 4 4 0 4 2 0 0 3 0 5 0 0 0 4 0 3 0 0 5 0 0 02. Other 5 E cin 5 V myr 0 0 0 0 0 0 0 0 4 Vmyr 0 0 0 0 0 0 0 0 0 0 0 0 0

D 3-8-11 E 3-8-11 FG 3-8-11 H 17-8-11 I 17-8-11

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Series/date: L Pfrom 289 296 297 299 320 335 340 348 355 359 365 370 379 383 387 395 398 415 417 422 426 431 433 435

to 296 297 299 308 335 340 348 355 359 364 369 379 383 387 395 398 415 416 422 425 429 433 435 438Dams* total inc top and bottom 8 2 3 9 6 6 9 8 5 7 6 10 5 3 9 4 18 2 8 4 4 3 3 4Dams* intact 5 2 3 7 4 5 5 8 4 6 6 10 3 2 9 4 18 2 8 4 4 0 0 0Dams* with side or bottom leak 2S 1B 0 0 2S 2S 1S 4S 0 1S 1B 0 0 1B1M 1B 0 0 0 0 0 0 0 3B1S1M 2B2S 2S2BDams* with downslope pit 3 1 3 1 2 3 4 1 0 1 0 1 1 1 3 4 2 0 1 0 0 2 1 1Dams* holding water 3 0 0 0 0 0 0 6 5 6 5 8 2 1 1 0 13 2 6 3 3 1 0 0Dams* trapping silt >12cm deep 6 2 3 5 5 5 9 6 5 6 5 10 4 2 8 4 17 2 6 3 3 2 3 3Gulley bottomSlope (Steep, Moderate, Slight, Flat) SL/M SL SL L SL ST SL/M M SL M VST M SL/F M SL M SL/M ST M SL/F SL/M M SL MAverage width m. 1.2 0.0-1.8 0.5 0.7-0.9 0.7 0.5 0.4-0.8 0.5-0.6 0.5 0.4-1.5 0.6 0.8-1.1 2 0.7 1 0.8 1.5 0-3.5 0.6-1.5 1.5 1.2 0.5-1.0 0.5-0.9 1.2Gulley floor, % length bare 10 10 70 5 70 40 40 5 10 10 60 75 75 30 50 80 60 20 15 5 70 35 15 15Calluna vulgaris 0 4 2 4 0 2 1 0 0 4 4 0 0 1 3 3 3 0 4 4 3 2 3 0Deschampsia flexuosa 2 3 1 2 1 1 2 3 0 3 2 3 1 4 2 1 4 1 2 3 2 1 1 5Eriophorum angustifolium 1 2 0 1 2 3 3 1 1 1 1 1 2 2 1 2 1 2 1 1 1 0 4 4Eriophorum vaginatum 3 0 0 0 3 0 5 2 0 2 3 2 0 3 4 0 2 3 3 2 0 0 0 3Molinia caerulea 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 2 1Sphagnum spp present 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 2Other 0 Vmyr 4 0 0 0 0 Emp 4 0 0 0 0 Emp 4 0 0 Emp 5 0 0 0 0 0 0 alg 3 0 0Gulley sides (1=E or N; 2=W or S ) 1. Slope approx degrees (90=vert) 45-80 15 40 40 40 40-50 30 45 40-50 40-50 60 30-50 45-80 25 30-45 50-70 15-80 60-90 15-45 10-20 15 20-45 25-70 15-201. Depth range (m) 1.1 0,3 0.7 0.6-0.8 0.7-0.9 0.5-0.9 0.4-0.7 0.8-1.2 1.1-2.2 1.1-2.2 1.3 1.0-1.4 2.0-2.5 1.2 1.1-2.0 1.3 0.9 2 0.5-0.9 0.3 0.3 0.4-0.7 1 0.6-1.21. Bare peat (All, Top, Bottom) (T) 0 B (T) A (T) A 0 0 0 T (T) (B) 0 (B) T (A) B (A) 0 A (A) (A) A1. Calluna vulgaris 0 1 1 4 3 2 1 2 2 1 1 4 2 1 1 3 1 1 3 1 1 1 3 31. Deschampsia flexuosa 2 2 3 1 2 3 2 1 1 2 2 3 1 2 2 1 2 2 2 3 2 2 1 21. Empetrum nigrum 3 3 0 3 0 4 5 0 0 0 0 2 3 3 4 0 4 4 4 5 4 0 0 01. Eriophorum angustifolium 1 0 2 2 1 1 4 3 3 3 3 1 4 4 3 2 3 3 1 4 3 3 2 11. Eriophorum vaginatum 0 0 0 0 0 0 3 0 4 4 0 0 0 5 0 0 0 0 5 2 0 0 0 01. Other Vacc myrt 0 4 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 02. Slope approx degrees (90=vert) 45 20 35 30-45 35-45 45 45 35-45 40 40-45 30-80 45-60 45-80 25 45-70 50-70 40-60 45-90 15-70 10-20 35 50-70 25-70 292. Depth range (m) 1.1 0.3 0.5 0.5-0.8 0.6-0.750.5-1.0 0.3-1.6 0.8-1.0 1.4 1.0-2.1 1.0-1.6 1.0-1.4 1.4 1.3 1.7-2.0 1.1-1.2 0.9-1.5 2 0.5-0.9 0.3 0.6 0.6-0.8 1 0.92. Bare peat (All, Top, Bottom) (T) 0 B (T) A A (B) 0 0 A (A) A (B) 0 (A) A (B) A (A) (A) A (A) 0 (A)2. Calluna vulgaris 0 4 0 4 4 1 1 2 2 2 2 5 2 1 3 4 1 2 3 2 1 2 2 12. Deschampsia flexuosa 2 1 2 1 1 2 3 1 1 3 1 1 1 2 1 2 3 1 2 3 2 1 1 32. Empetrum nigrum 3 2 3 3 3 3 5 0 4 4 0 2 3 3 2 3 4 4 4 1 0 0 0 02. Eriophorum angustifolium 1 3 1 2 2 4 2 3 3 1 4 4 4 5 4 1 2 3 1 5 3 3 0 22. Eriophorum vaginatum 0 0 0 0 0 0 2 0 0 0 3 3 0 4 5 0 0 0 0 4 0 0 4 02. Other Vacc myrt 4 0 0 5 0 5 0 0 0 0 0 0 0 0 0 0 0 0 0 5 0 0 3 0

J 24-8-11 K 24-8-11 M 21-9-11 N 21-9-11 Q 28-9-11

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Series/date: S Tfrom 200 207 210 221 440 320

to 207 210 221 222 446 327Dams* total inc top and bottom 8 4 12 2 7 8Dams* intact 6 1 7 0 2 5Dams* with side or bottom leak 2S 3S 5S2B 2B1S 1B4S 2S1BDams* with downslope pit 0 0 0 0 0 1Dams* holding water 8 4 11 2 3 5Dams* trapping silt >12cm deep 8 4 12 2 7 5Gulley bottomSlope (Steep, Moderate, Slight, Flat) M ST M ST M MAverage width m. 1.3 0.3-1.1 1.2 0.8 1.0-1.5 0.4-2.0Gulley floor, % length bare 97 40 95 100 70 80Calluna vulgaris 0 0 0 0 0 2Deschampsia flexuosa 0 1 0 0 2 1Eriophorum angustifolium 1 2 1 0 1 3Eriophorum vaginatum 2 0 0 0 0 4Molinia caerulea 0 0 0 0 0 0Sphagnum spp present 0 0 0 0 0 0Other 0 0 0 0 0 0Gulley sides (1=E or N; 2=W or S ) 1. Slope approx degrees (90=vert) 40-70 45-70 70 80 25 15-301. Depth range (m) 1.3 1.8 1.3 2 0.7 0.3-0.51. Bare peat (All, Top, Bottom) A T (A) A (A) A1. Calluna vulgaris 2 2 2 0 2 11. Deschampsia flexuosa 3 1 1 0 3 21. Empetrum nigrum 0 0 0 0 0 01. Eriophorum angustifolium 1 3 3 1 1 31. Eriophorum vaginatum 0 0 0 0 0 01. Other 0 0 0 0 0 02. Slope approx degrees (90=vert) 40-60 45 60 50-85 40 15-302. Depth range (m) 1.5 1.8 1.3-2.0 2 0.7 0.52. Bare peat (All, Top, Bottom) A T A B (A) A2. Calluna vulgaris 1 2 1 0 1 12. Deschampsia flexuosa 2 1 3 1 3 22. Empetrum nigrum 0 0 0 0 0 02. Eriophorum angustifolium 3 3 2 2 2 32. Eriophorum vaginatum 0 0 0 0 0 02. Other 0 0 0 0 0 0

R 28-9-11