Natural Flood Management
Working with natural processes to manage flood risk,
benefit people & wildlife
Ann Skinner
Senior Conservation Advisor, EA National Biodiversity team
CIEEM SW Geographic section conference, December 2015
What is flood risk
management?
Flood risk – the probability of
flooding occurring combined with
the harmful consequences for
people, infrastructure & the
environment
Risk management – altering the
balance of the factors that make
up flood risk, through amongst
other things, “maintaining or
restoring natural processes”
Section 3, Flood & Water Management Act 2010
Natural flood management
Mitigated hard
engineering
Hard engineering
Adapted from RSPB
Heavily
modified river
or coastline
Flood walls, pump
drainage, dry
washlands
-
Natural Processes
Green roofs,
permeable paving
Floodplain disconnected
from channel/sea, except in
exceptional circumstances
Soft engineering/
restoration
Wet washlands,
balancing ponds,
regulated tidal
exchange, swales
+
managed realignment, upland
grip blocking, remeandering
Floodplain connected with
channel/sea with high degree of
control
Natural Flood Risk
Management
(Semi) natural
river or
coastline
Natural
floodplain/coastal
zone (minimal
intervention)
Floodplain connected with
channel/sea with high degree
of freedom
…taking action to manage flood and coastal erosion risk by
protecting, restoring and emulating the natural regulating
function of catchments, rivers, floodplains and coasts
Examples of natural flood management
Upland grip blocking &
reduced stocking
densities
Shelter belts and
hedgerows
Woodland & gully planting
Blue-green infrastructure (eg SUDS) in urban areas
River & floodplain
restoration
Remove redundant in-stream structures
Floodwater storage in
wetlands/washlands
Two-staged channels
Woody debris dams
Water level
management
Sand dunes & shingle
beaches as natural
defences
Setting back flood
embankments
Changes in land
use/management;
buffer strips, rural
sustainable drainage &
cover crops
Managed realignment of
coastal defences & salt
marsh creation
Sand engines
It’s not new &
we are good
at it!
The natural flood management journey
PAG1 2001
Floods Directive 2007
Pitt Review 2008
Defra multi-objective pilot projects
Sutcliffe Park, Lewisham
The natural flood management journey
Flood Risk Regulations 2009
Flood & Water Management Act 2010
National FCERM Strategy for England 2011
EU Natural Water Retention Measures 2014
EA position statement 2015
Alkborough Flats, Humber
Barriers identified by stakeholders
Identifying barriers to delivery of better environmental
and social outcomes through natural flood management
Risk Policy Analysis, August 2006
Techniques
• Few catchment-wide demonstration sites
• Standards of protection uncertain
• Valuation of social & environmental benefits not well
represented in appraisal process
Competency
• Lack of guidance on NFM & impact on environmental &
social interests
• Ecosystem service valuation poorly understood / not
widely accepted
Culture
•
•
•
•
•
Engineers favour engineered solutions
General reluctance / resistance to change
Authorities risk averse
Remote solutions viewed with scepticism
Perception that stakeholder engagement hinders
Identifying barriers to delivery of better environmental
and social outcomes through natural flood management
RPA, August 2006
Policy
• Policies not joined up across Government Depts – not
always compatible / complementary
• Responsibility dispersed between agencies
• Goal of sustainability is long term; rarely features in
short term planning & funding decisions
• Approach doesn’t comprehensively include social &
environment issues - hard to value
• Funding streams kept separate
Funding • Multi Criteria Analysis favours economics – socioeconomic factors not given equal weight
• No clear system for paying for flood management
benefits from changes in land use
Greater working with natural processes in flood and
coastal erosion risk management
A response to Pitt Review Recommendation 27, EA 2012
Strategic planning – targeted action to progress policies that
promote natural flood management
Policy framework – ensure project appraisal guidance
facilitates multiple benefit schemes
Science & modelling – Identify synergies, fill gaps in
catchment analysis & planning tools
Funding & incentives – improve joint working, target land
management advice and progress innovative funding
Partner & community engagement –involve local
communities at earliest opportunity
Culture, skills & training – develop guidance and investigate
potential for multiple benefit schemes
Piecing it together....how NFM might work
within a catchment
Upland grip
blocking
On farm flood
storage area
Woodland
planting
In stream
woody debris
Contour ploughing
to reduce
sediment loads
Community at
risk defended
Re-connecting
the flood plain
Managed re-alignment
Washing topsoil down the drain – January 2014
Run-off
Absorption
Multiple
Benefits
The importance
of soil management
KILLER FACT Defra Soil Strategy for England 2009: water treatment cost of
soil erosion approx £21 million p.a. in England. Agriculture responsible for
75% of the sediment in rivers and 25% of the phosphorus
Steart natural flood management scheme
100
90
80
Wave energy
70
60
50
40
30
20
10
0
0
20
• 250 hectares of new intertidal and wetland habitat
• Contributes to the protection of 100,000 properties
• Value of property protected - £5 billion
40
60
Saltmarsh width
80
100
Blakeney Freshes (Norfolk) post storm-surge
Steart natural flood management scheme
• 250 hectares of new intertidal and wetland habitat
• Contributes to the protection of 100,000 properties
• Value of property protected - £5 billion
What else do we want?
Floodplain meadows!!!
KILLER FACT: floodplain meadows store/process sediment-bound P &N, converting
excess nutrients into agriculturally valuable crop that supports pollinating insects
Pickering – slowing the flow
Flood plain woodland planting
Upland grip blocking
Woody ‘debris’ bunds
Buffer strips
Pickering
Potential barriers to natural flood
management
70
60
No. breeding pairs
50
40
Years with
full and
partial
flooding
during
spring &
early
summer
30
20
10
0
1952
1957
1962
1967
1972
1977
1982
1987
1992
1997
2002
Ouse Washes flood storage area and internationally important nature reserve
Urban & rural SUDS
Suds
Flood storage areas
Integrated flood schemes
Green/blue infrastructure
Lustrum Beck
Using GIS to identify flow pathways;
mapping data & aerial imagery to identify
suitable locations for NFM
Uncertainty
Culture
Funding
Complex
Medmerry
Developing the Evidence Base
Evidence
Directory
Opportunity
Maps
Catchment &
Coastal Labs
Devon Beaver Project: Site Overview
•
•
•
•
2.8 ha fenced site in N. Devon, UK.
A pair of beavers introduced in 2011.
Now 5 beavers in the site.
Dramatically changed site from small
first order tributary running through
wet woodland, to a diverse mosaic
wetland environment.
~ Darling, so how many
properties are we protecting
from flooding?