1. VNN Workshop. Leeds, 9th May 2012
Peatlands and water quality: degradation,
restoration and the Water Framework Directive
Tim Allott
Martin Evans (UoM), James Rothwell (UoM), Chris Evans
(CEH), Don Monteith (CEH), Tia Crouch (MFF), Jon Walker
(MFF), Ewan Shilland (UCL), Rick Battarbee (UCL)

2. VNN Workshop. Leeds, 9th May 2012
A starting point: the River Ashop, Derbyshire
• 28 km2 catchment
• Degraded peatland headwaters
• Low pH
• Elevated metal concentrations
(e.g. Lead, zinc, copper)
• High DOC / colour
• High suspended sediment load
(POC/FPOM)
• Impoverished fish community
• WFD ‘fail’ on fish, zinc, copper
• Current status ‘Moderate’
• Overall objective ‘Good status’
by 2027

3. VNN Workshop. Leeds, 9th May 2012
Impacts of peat degradation and restoration on
water quality?
• Degraded peatland headwaters
• Restoration via ditch blocking, re-vegetation and gully
blocking
Direct WFD concerns
• Low pH
• Specific pollutants (e.g. zinc, arsenic, etc)
• Biological quality elements (e.g. fish, invertebrates)
• (Ammonia, phosphate, DO, other specific pollutants)
Indirect WFD concerns
• High DOC / colour
• High suspended sediment loads (POC/FPOM)

4. VNN Workshop. Leeds, 9th May 2012
Intact peatlands and water quality regulation
• Oligotrophic – low
nutrient
concentrations
• High water table
conditions
• Acidic
• Accumulating peat
(organic matter)
Drainage waters
Intact accumulating peats retain pollutants •Moderate DOC and organic acidity
• Reduction of deposited SO4,NO3 •Low POC
• Storage of deposited metals •Low metals
•Low nutrient export

5. VNN Workshop. Leeds, 9th May 2012
Peat degradation
Erosion, drainage and water table change – physical
and hydro-chemical effects
08 September 07 November 07 December
08/08 2008 09/08October 2008
09 August 2008 08 10/08 2008 11/08 2008 12/08January 2009
06
-100
0
Water Table Depth (mm)
100
200
300
400
Intact
500
Gullied
600

6. VNN Workshop. Leeds, 9th May 2012
Degraded peatlands compromise water quality
• Gully erosion and bare peat
• Grips and peat drainage
• Water table drawdown
• Reduced peat accumulation
• Aerobic decomposition
Image from Holden et al (2007)
Drainage waters
• High POC
• Increased DOC
Degraded peats and pollutants • Increased SO4 and NO3
• Reduced/zero C, SO4,NO3, NH4, metal • Increased acidity
accumulation • Elevated metals and toxic
• Transformation from sink to source substances

7. VNN Workshop. Leeds, 9th May 2012
Peatland restoration and water quality
responses
• Grip / drain blocking
• Gully blocking
• Re-vegetation of bare peat
• Stabilization of eroding
/ditched peat
• Raising water table conditions
Known/likely impacts on:
• Suspended sediments ?
• Metals and toxic substances ?
• DOC ?
• Acidity ?

8. VNN Workshop. Leeds, 9th May 2012
Re-vegetation shuts down suspended sediment
production and release
10000
1000
SSC m g/l
100
10
1
0.001 0.01 0.1 1 10 100 1000
Q Ls-1km-2
= data from intact reference site Evans M and Worrall (2009) NE Report

9. VNN Workshop. Leeds, 9th May 2012
Re-vegetation shuts down suspended sediment
production and release
Sediment
Loads gC m2 a-1
Joseph South 4.07
Joseph North 1.43
Trenches North Hi 157.64
Trenches South 804.42
Control 1.87
Evans M and Worrall (2009) NE Report

10. VNN Workshop. Leeds, 9th May 2012
Drain and gully blocking reduces suspended
sediments/FPOM
• Drain blocking significantly reduces
sediment yields (Holden et al 2007;
Wilson et al 2011)
• Gully blocking traps FPOM (Evans M et
al 2004)
• Drain blocking, FPOM changes and
improved stream biodiversity
(Ramchunder et al. 2012)

11. VNN Workshop. Leeds, 9th May 2012
Peat storage of atmospherically derived metals
and toxic substances

12. VNN Workshop. Leeds, 9th May 2012
Metal release from degraded peatlands:
sinks into sources
Data from headwaters of the River Ashop
Rothwell et al (2012) Env. Poll.
08 September 07 November 07 December
09 August 2008 2008 08 October 2008 2008 2008 06 January 2009
-100
0
W a t e r T a b le D e p t h ( m m )
100
200
300
400
500
600
• Outputs > inputs
• Significant export from the headwater peats
• Contrasting controls for different metals

13. VNN Workshop. Leeds, 9th May 2012
Peatland restoration and reductions in metal
release
Limited empirical evidence, but..
• Reduced suspended sediment and
FPOM release will reduce metal
export
• Three potential mechanisms
associated with re-wetting:
– Reduced oxidation/acidity would reduce
metal release (e.g. Zn, Ni)
09 August 2008
-100
08 September
2008 08 October 2008
07 November
2008
07 December
2008 06 January 2009 – Reduced DOC would reduce export of
0
bound metals (e.g. Pb, Cu)
– Redox changes might increase the
W a t e r T a b le D e p t h ( m m )
100
200 release of redox sensitive metals (e.g.
300 As, Fe, Mn)
400
500
600

14. VNN Workshop. Leeds, 9th May 2012
Degradation increases sulphate / nitrate
release and acidity
• Oxidation of stored sulphur and nitrogen
• Evidence from spatial comparisons (e.g. Daniels et al 2008), and
indirectly from drought response studies (e.g. Clarke et al 2005)
• Land management impacts superimposed on a long-term history
of acid deposition
Clarke et al (2005)
Daniels et al (2008)

15. VNN Workshop. Leeds, 9th May 2012
Degradation, restoration and DOC/colour
• Increasing reports that ditch blocking
reduces DOC (e.g. Wallage et al 2006;
Armstrong et al 2010; SCaMP 2011; Wilson et al
2011)
• But a lack of consistent behaviour
between systems and over the
(generally) short time periods of study
• Evidence of (transient?) DOC increases Wallage et al (2006)
after blocking (e.g. Worrall et al 2007)
• Evidence that in some cases re-wetting
might increase DOC loss (e.g. Daniels et al.
2008 study of catchments with significant stores
of sulphur)
• Need fuller understanding of process
controls in order to generalise/model
Daniels et al. (2008)

16. VNN Workshop. Leeds, 9th May 2012
Climate change impacts
08 September 07 November 07 December
09 August 2008 2008 08 October 2008 2008 2008 06 January 2009
-100
Degraded systems as 0
W a te r T a b le D e p th (m m )
climate change
100
200
analogues? 300
400
500
600
DROUGHT
Blackstone Edge Reservoir
Tipping, Rothwell et al. 2010. Environ. Pollut., 158: 1521-1529

17. VNN Workshop. Leeds, 9th May 2012
Long term monitored data
• Crucial context for water quality
impacts and catchment
management
• Regional / national patterns
• Long term drivers (climate and
atmospheric deposition)
10
9
Dissolved Organic Carbon
concentration (mg l-1)
8
7
6
5
4
3
2
See Acid Waters Monitoring 1
Network website and reports 0
1988 1993 1998 2003 2008

18. VNN Workshop. Leeds, 9th May 2012
Upland waters: aqua incognita?
• 82% of GB river length lies within
catchments of < 10km2
?
• Of the upland river length, 97% lies in
catchments < 10 km2
• Not many EA monitoring sites above
300m!
• Much upland policy is based on a
small, disconnected and financially
vulnerable set of monitoring sites
(e.g. AWMN sites)
• Require increased monitoring, both
investigative and surveillance

19. VNN Workshop. Leeds, 9th May 2012
Investigative monitoring: Bamford/Ashop
catchment metals study (EA/STW/Moors for the Future)
?

20. ENVIRONMENTAL CHANGE RESEARCH CENTRE
An Upland Waters Monitoring Network for the UK
(based on a science partnership of UCL, CEH, QMUL and SG; supported by
Defra, DOENI, WG, SG, CCW, EA, Forestry Commission, CEH and ENSIS Ltd)

21. The UK Upland Waters Monitoring Network
Plans and Proposals
1. To build on (and replace from 2013) the Acid Waters Monitoring
Network of 24 lake and stream sites across the UK

22. The UK Upland Waters Monitoring Network
Plans and Proposals
2. To add new sites conforming strictly to AWMN protocols for water chemistry
and biology (diatoms, aquatic plants, macro-invertebrates, fish) in higher
alkalinity regions non sensitive to acid deposition
3. To add a small number of non-AWMN “associated” sites where high quality
long term data-sets already exist but do not conform strictly to AWMN protocols
4. To complete the installation of temperature loggers and flow and water-level
loggers at existing AWMN sites
5. To introduce additional protocols to AWMN sites for monitoring nutrients (e.g.
low detection level TP and chl a), carbon export (e.g. POC in streams and
sediment traps) and catchment land-cover change (e.g. repeat fixed point
photography)
For further information see www.awmn.defra.gov.uk
or contact Rick Battarbee or Ewan Shilland

23. VNN Workshop. Leeds, 9th May 2012
Summary points
• Key upland WFD concerns: acidity, specific pollutants
(metals), biological quality, DOC/colour, suspended
sediments/FPOM
• Peat degradation impacts all these!
• Peat restoration has clear and demonstrable benefits
for suspended sediments
• Less consensus over other restoration related WQ
improvements than policy/practitioner community
would like (timescales, variation between case study
data, lack of data in many cases)
• Key role of monitoring and improved process
understanding