Beaver reintroduction projects in the UK are quantifying the multiple environmental benefits of beavers. Data from the Devon Beaver Project shows that beaver dams increase water storage, attenuate peak flows, and may filter diffuse pollutants. Over 100 tons of sediment and 15 tons of carbon have been stored in ponds on the site. The Cornwall Beaver Project is monitoring the impacts of beavers on a larger second order tributary catchment. The River Otter Beaver Trial is assessing beaver impacts at the full catchment scale of 250 square kilometers. Research demonstrates that restoring landscape structure through beaver reintroduction can improve water storage and flow regulation while reducing flooding and pollution risks.

1. Dr Alan Puttock and Professor Richard Brazier
a.k.puttock@exeter.ac.uk r.e.brazier@exeter.ac.uk
Richard Brazier1, Mark Elliott2 and Alan Puttock1
Quantifying the Multiple Environmental Impacts of
Reintroducing the Eurasian Beaver

2. Context
• Recent extreme rainfall in the UK, caused major socio-economic and environmental damage:
• Surface water flooding
• Soil erosion
• Diffuse pollution from agricultural land
• Solutions focussed on downstream palliative approaches i.e. building flood defences,
dredging channels etc…
• Rewilding/Rewetting at landscape scales may offer alternative/complimentary solutions:
• Enhancing resilience of downstream flood defences,
• Maintain elevated baseflows in rivers during droughts
• Keeping soil and nutrients on the land
• Whilst also delivering much needed biodiversity and other benefits…
• Talk demonstrates how we can quantify the role that landscape restoration science might
play as a ‘Nature Based Solution’ to the environmental problems that (for the most part) we
have created… Can we make a case for rewilding beyond biodiversity?

3. Landscape Restoration Projects
Moorland Restoration
Beaver Reintroduction
Unimproved Grassland Recreation

4. Reintroduction of Castor Fiber – the Eurasian Beaver
Ecosystem Engineers and Keystone Species
A need for understanding and projects across different landscapes and scales:
• Devon Beaver Project (1st order tributary)
• Cornwall Beaver Project (2nd order tributary)
• River Otter Beaver Trial (catchment scale)
• Scoping for new projects and visiting sites in other countries

5. Puttock, A., Graham, H.A., Cunliffe, A.M., Elliott, M., Brazier, R.E.,
2017. Eurasian beaver activity increases water storage,
attenuates flow and mitigates diffuse pollution from intensively-
managed grasslands. Sci. Total Environ. 576, 430–443.
doi:10.1016/j.scitotenv.2016.10.122
http://www.sciencedirect.com/science/article/pii/S004896971632
3099

6. Sub-catchment scale: Devon Beaver Project
3 ha site with upstream catchment of 20 ha dominated by intensively managed grassland

7. Devon Beaver Project: Overview
• Fenced 1.8 ha site in North Devon, UK
• 1st order tributary draining from IMG
• A pair of beavers introduced in 2011
• Dramatically changed site from small
first order tributary running through wet
woodland, to a diverse mosaicked
wetland environment.

8. Devon Beaver Project: Experimental Design
Quantifying Water Quality and
Quantity entering, leaving and stored
in the site:
1. Flow in and out (continuous
monitoring) and pond storage.
2. Rainfall in (continuous monitoring).
3. pH, suspended sediment, dissolved
organic carbon, nitrogen, phosphate,
colour (flow based monitoring).

9. Devon Beaver Project: Results – water storage
Puttock, A., Cunliffe, A. M., Anderson, K., & Brazier, R. E. (2015). Aerial photography collected with a multirotor drone
reveals impact of Eurasian beaver reintroduction on ecosystem structure. Journal of Unmanned Vehicle Systems,
150429143447007. http://doi.org/10.1139/juvs-2015-0005

10. Devon Beaver Project: Results - Flow Attenuation
Project has now been collecting continuous flow and rainfall data for 2+ years, quantifying the
rate and amount of water entering and leaving the site.
Results (from 70+ rainfall-runoff events) indicate that beaver activity, particularly the building of
ponds and dams, moderates the channel response to rainfall following storm events, potentially
reducing the risk of flooding downstream.
• Event Rain = 24 mm
• Above Beaver (blue)
Peak Discharge = 0.11 (mᶟ s¯¹)
Storm event discharge = 2923 (m3)
• Below Beaver (red)
Peak Discharge = 0.04 (mᶟ s¯¹)
Storm event discharge = 1493 (m3)

11. Devon Beaver Project: Results - Flow Attenuation
• Each x is a storm
• Flow in (above beaver) is greater with
higher peak discharge
• Lag times (peak rainfall to peak flow)
much shorter above beaver site than
below
• Demonstrates flow attenuation due
to beaver activity...

12. Devon Beaver Project Results – water quality
Storm monitoring (17 events, 178 samples above,
119 below), suggests site may act as a sink or
filter for diffuse water pollutants from agriculture
(suspended sediment, nitrogen and phosphate).
However, more organic matter in the site, so
potentially results in a greater loss of dissolved
organic carbon than comparative agricultural
land.

13. Devon Beaver Project Results – Sediment/Nutrient Storage
• During the 11 storm events monitored,
1.6 t of sediment was lost from the 20 ha
of grassland upstream of the beaver site.
0.4 t of sediment left the site during these
same 11 storms.
• Where is this sediment?
• Further work ongoing to work out to
determine:
1. Where sediment is being stored
2. What nutrients are associated with this
sediment
• Give a deeper mechanistic understanding
of the relationship between structure and
function at the beaver impacted site.
• Probing determined volume of sediment
stored in ponds.
• Pond sediment samples collected.
• Currently being analysed for: carbon,
nitrogen, phosphorus, particle size, trace
metals.

14. Devon Beaver Project Results – Sediment/Nutrient Storage
~100 T of Sediment
~15 T of Carbon

15. New Projects: Cornwall Beaver Project
http://www.cornwallwildlifetrust.org.uk/living-landscapes/cornwall-beaver-project
https://vimeo.com/165146032

16. New Projects: Cornwall Beaver Project
http://www.cornwallwildlifetrust.org.uk/living-landscapes/cornwall-beaver-project
• Site on one of 3 main
tributaries of Tresillian
entering Ladock (2nd order).
• Total Catchment + 2300 ha
• Site catchment 134 ha.
• Dominated by Farmland.
• Potential for flow partitioning
of all tributaries.
• Relate flow through site (Qt
and Qp) to that observed at
Ladock
• Currently undertaking
baseline monitoring

17. Cornwall Beaver Project: Hydrology
Storm Angus November 2016
Total Rainfall (mm) 68.6
Main Event Rainfall (mm) 17.6
Peak-Peak Lag time AB (min +/- 15 min time steps) 75
Peak-Peak Lag time BB (min +/- 15 min time steps) 75

18. © Emilie Grand-Clement
© Emilie Grand-Clement

19. Catchment Scale: River Otter Beaver Trial
http://www.devonwildlifetrust.org/devons-wild-beavers/
https://www.youtube.com/watch?v=4KBuUFZfrn8
• In February 2015, Devon Wildlife Trust on behalf of River Otter
Beaver Trial partners, granted a licence by Natural England
under the Wildlife and Countryside Act 1981, to re-release
beavers, into the River Otter Catchment (250 km2).
• As part of licence, a Monitoring Framework submitted, with
University of Exeter monitoring a central component.
• Appointment of Hugh Graham to undertake a PhD.

20. Catchment Scale: River Otter Beaver Trial
http://www.devonwildlifetrust.org/devons-wild-beavers/

21. Summary and conclusions
Restoring the ‘structure’ of our landscapes can significantly alter ecosystem function:
- Storing more water
- Attenuating flooding (reduced and desynchronised flow)
- Releasing more water in drought to elevate river baseflows
- Mitigating diffuse pollution from agriculture
- Storing carbon
Such change also enhances biodiversity; wetland vegetation, aquatic ecology,
mammal and birdlife
With Beavers present >500 years ago, we had a ‘nature-based solution’ to water
resource and indeed whole ecosystem management
Removing this keystone species, the ‘trophic cascade’ that it supported collapsed
The structure and function of most of our rivers was also dramatically affected…
even more so by intensification of agriculture and drainage of our moorlands
Research projects demonstrate the value of more wild, wet, roughly structured
landscapes, perhaps we should consider bringing them back..?

22. Thanks to all colleagues, funders and associated partners
Devon Beaver Project
Devon Beaver Project is led by Devon Wildlife Trust and the University of Exeter, and funded by Westland Countryside Stewards. Particular thanks
go to John Morgan, the site owner, for hosting the reintroduction project and allowing site access for researchers. The 3D Robotics Y6 was
supplied by the University of Exeter’s Environment and Sustainability Institute (ESI) environmental monitoring drone lab.
River Otter Beaver Trial
The River Otter Beaver Trial is led by Devon Wildlife Trust, working in partnership with the University of Exeter, Clinton Devon Estates and the
Derek Gow Consultancy. Data has been provided by the Environment Agency. Expert independent advice is also provided by the Royal Zoological
Society of Scotland (Roisin Campbell-Palmer and Simon Girling), Professor John Gurnell and Gerhard Schwab. The trial is licenced by Natural
England.
Cornwall Beaver Project
Cornwall Wildlife Trust is hosting the Cornwall Beaver Project on behalf of a wider partnership of individuals and organisations including;
University of Exeter, University of Southampton, University of Plymouth, CoaST and Woodland Valley Farm.