Natural Flood Management

Ann Skinner

Senior Conservation Advisor, EA National Biodiversity team

CIEEM SW Geographic section conference, December 2015

Working with natural processes to manage flood risk,benefit people & wildlife

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

Floodplain connected with channel/sea with high degree

of freedom

Floodplain connected with channel/sea with high degree of

control

Floodplain disconnected from channel/sea, except in exceptional circumstances

Natural floodplain/coastal

zone (minimal intervention)

managed re-alignment, upland grip blocking, re-

meandering

Wet washlands, balancing ponds, regulated tidal

exchange, swales

Green roofs, permeable paving

Flood walls, pump drainage, dry

washlands

Natural Flood Risk Management

Soft engineering/restoration

Mitigated hard engineering

Hard engineering

Heavily

modified river

or coastline

(Semi) natural

river or

coastline- Natural Processes +

Adapte

d f

rom

R

SP

B

…taking action to manage flood and coastal erosion risk by

protecting, restoring and emulating the natural regulating

function of catchments, rivers, floodplains and coasts

Woodland & gully planting

Blue-green infrastructure (eg SUDS) in urban areas

Remove redundant in-stream structures

Two-staged channels

Woody debris dams

Sand dunes & shingle

beaches as natural

defences

Upland grip blocking &

reduced stocking

densities

Shelter belts and

hedgerows

River & floodplain

restorationFloodwater storage in

wetlands/washlands

Sand engines

Changes in land

use/management;

buffer strips, rural

sustainable drainage &

cover crops

Water level

management

Setting back flood

embankments

Managed realignment of

coastal defences & salt

marsh creation

Examples of natural flood management

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

Funding

• Approach doesn’t comprehensively include social &

environment issues - hard to value

• Funding streams kept separate

• Multi Criteria Analysis favours economics – socio-

economic 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 catchmentUpland grip

blocking

On farm flood

storage area

Managed re-alignment

Woodland

planting

Contour ploughing

to reduce

sediment loads

In stream

woody debris

Community at

risk defended

Re-connecting

the flood plain

Washing topsoil down the drain – January 2014

Absorption

Run-off

Multiple BenefitsThe 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

• 250 hectares of new intertidal and wetland habitat

• Contributes to the protection of 100,000 properties

• Value of property protected - £5 billion

0

10

20

30

40

50

60

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80

90

100

0 20 40 60 80 100

Wave

energ

y

Saltmarsh width

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

Blakeney Freshes (Norfolk) post storm-surge

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

Pickering

Upland grip blocking

Woody ‘debris’ bunds

Flood plain woodland planting

Buffer strips

Potential barriers to natural flood management

Ouse Washes flood storage area and internationally important nature reserve

0

10

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60

70

1952 1957 1962 1967 1972 1977 1982 1987 1992 1997 2002

Years with

full and

partial

flooding

during

spring &

early

summer

No

. b

reed

ing

pa

irs

Suds

Green/blue infrastructure

Flood storage areas

Integrated flood schemes

Urban & rural SUDS

Lustrum Beck

Using GIS to identify flow pathways;

mapping data & aerial imagery to identify

suitable locations for NFM

Uncertainty Funding

Culture 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?