natalie angelopoulos prof ian cowx hull international ... conference/session 3a...natalie...

Assessing the impact of river rehabilitation

schemes – a missing dimension or

unnecessary procedure?

Natalie Angelopoulos

Prof Ian Cowx

Hull International Fisheries

Institute (HIFI)

(Petroski 1992) source Downs & Kondolf 2002

“No one wants to learn by

mistakes, but we cannot

learn enough from

success to go beyond the

state of art”

Evaluate overall project effectiveness

- Testing objectives

- Allows for the correction of errors

Enables feedback – to improve rehabilitation projects

Development of existing project plans

Increase our knowledge of restoration methodologies

Why monitor?

Identify measures for

rehabilitation

Identify pressures

responsible for

degradation

Uncertainty and risk assessmentHave they been

proven? e.g.

FORECASTER

Economically & socially

acceptable

Reject & identify

alternative solutions

Implement strategy to

improve habitat

Post – project

monitoring &

evaluation scheme

How is fish habitat area

degraded?

Is fishery

performance &

environmental

quality satisfactory?

Reset objectives for

sustainability,

conservation & a

higher ecological

status

HD & WFD Driver

Establish objectives for river

rehabilitation

Evaluate river health &

fish status – monitoring &

assessment

yes

no

Where Does Monitoring Fit in to the River Rehabilitation Project Planning

Framework?

What should we monitor? FISH

River habitat assessment

HABSCORE

PHABSIM

MesoHABSIM

• Reach Dimensions

• Substrate & Flow

• Percentage Cover

Others

- Invertebrates

Fish monitoring methods

Electric fishing

- Quantitative

- Semi-quantitative

Micromesh seine netting

Fish population assessment

- Indicator species

- Single species or entire community

- Population dynamics, density, recruitment

- Age and growth determination

When & How should we monitor?

WHEN?

Pre-monitoring – to assess the river health & fisheries status

- Baseline Data

- Reference Condition – what is a reference site?

Post monitoring – to test objectives against results

HOW?

Frequency of sampling variables

Temporal monitoring

- Short term

- Long term (5-10 years)

Spatial monitoring – to represent all different habitats

How long does it take to see a response?

Long term

Short

term

2006

2007

2009

Rottal Burn – Site 13c

Identifying natural fluctuations in populations

2006

2007

2009

Rottal Burn – Site 13d

Identifying natural fluctuations in populations

Need to be aware the influence of variable recruitment and life cycle processes on the “abundance” of species at any one time!

Intensity of human impact

Metr

ic

positive response

no response

unpredictable response

negative response

Time

Improving

Decline

Variable

Stable

Action required

All fine

?

Highlights the need to setting attribute targets and interpreting monitoring data

Flood defence works – River Don

Brief overview:

Shoal and tree removal in five reaches

Fish populations were assessed before (February 2010) and after (August

2010) flood defence activities

R

E

S

T

O

R

A

T

I

O

NBEFORE AFTER

Length distributions of grayling in the Blonk Street section, River Don, February 2010 and August 2010

Flood defence works River Don

Findings:

Data suggested flood defence works had no obvious impact on the fish

populations in the study reach

Future actions:

Monitoring will continue for the next 2 years to identify any

changes in fish populations in response to habitat

modifications

Why:

- To evaluate effectiveness of project

- Success criteria - Test objectives against results

- Project appraisal

- Contributes to current knowledge to benefit future projects

Evaluation & Reporting

DO YOU DO IT?

COMMUNICATION & CO-OPERATION

Transfer of Knowledge

Multidisciplinary – Geomorphologists, hydrologist, fisheries scientists etc…

Groups – Scientists, stakeholders, practitioners & general public

Learn from rehabilitation efforts:

River Restoration Centre (RRC)

Environment Agency

Association of Rivers Trusts

University Studies

European Centre for River Rehabilitation

FORECASTER (Hull University,

Deltares)

RESTORE

2010-2013

WFD-REFORM

2011-2015

WFD REFORM

Eawag

JRC

25 Partners throughout

Europe

Deltares

Alterra

AU-NERI

BOKU

Cemagref

DDNIEcologic

IGB

RECETOXNERC-CEH

QMUL

SLU

SYKEUDE

UHULL

UNIFI

UPM

VU-IUM

WULS

CEDEX

DLG

EAISPRA

Adaptive Management Framework For River

Restoration?

• Promote restoration as a programme rather than

beginning and end points

• Feedback loop overcomes complexities & uncertainties

• Allows for developments and improvement to the project

• Transferable to different rehabilitation projects across a

range of diverse rivers

• Encourages scientific communication

• Encourages monitoring & evaluation to be incorporated

in all programmes

Acknowledgements:

Hull International Fisheries Institute

Wild Trout Trust

Trent Rivers Trust

Environment Agency

East Yorkshire Chalk Rivers Trust

National Trust

Cain Bio-Engineering

Land owners

Fishery owners

Rehabilitation of hydrogeomorphological processes in a lowland UK river:

Quantifying and assessing the effects of large wood reintroductions

Gemma Harvey1, Alex Henshaw1, Chris Parker2, Carl Sayer3 & Murray Thompson3,4

in collaboration with:

Project Manager: Dave Brady5, Site Manager at Blickling Hall, Norfolk

1School of Geography, Queen Mary, University of London; 2Department of Geography and Environmental Management, University of

the West of England; 3Department of Geography, UCL; 4Natural History Museum, London; 5National Trust

Contact: [email protected]

Overview

• Context

• The River Bure rehabilitation project

• Monitoring and research

• Some initial findings

• Outcomes so far and future work

• A natural feature of wooded river systems and an important influence on fluvial landform

development at the patch and reach scale:

• In pristine systems, wood budgets reflect input processes (recruitment) and output

processes (physical and biological) and the size distribution of the wood

• Wood budgets are heavily modified in most rivers as a result of:

• Large scale woodland clearance over long timescales

• Direct removal (de-snagging) to reduce risks associated with flow conveyance,

blockages at structures, bank erosion, morphological change

• Channel modifications – influencing lateral and longitudinal connectivity

Wood accumulations in river channels

Keller and Swanson (1979)

Gregory and Davis (1992)

Influence on hydrogeomorphology and ecology

Wood in river rehabilitation

“Temporarily reintroduce natural or quasi-natural LWD loadings until such time as the riparian

zone is rehabilitated to an extent where natural processes of LWD recruitment can take

place…

…LWD is replaced to provide a number of functions such as bed protection, bank protection

and habitat creation”

Often, the focus has been on wood as a flow deflector:

• Introducing flow variability

• Inducing localised erosion and deposition without increasing risks associated with bank

scour or impoundment of flow

Viles et al. (2008)

(Erskine and Webb, 2003)

• Chalk stream in north Norfolk

• National Trust Blickling estate

• Woodland, parkland and farmland

Reintroduction of large wood: the River Bure, Norfolk

• Over-widened due to historic dredging activities and heavily silted

• Large wood previously removed by fishing club and EA

• Fishing club and the National Trust considered wild trout stocks and overall conservation

value to be relatively low

• Site Manager Dave Brady identified an opportunity for restoration by felling trees into the

river to improve habitat and restore a natural process

Reintroduction of large wood: the River Bure, Norfolk

Dave Brady developed and implemented the project based on some key principles

Project aims:

• To improve river habitat by re-instating in-channel large wood features

• To increase the stock of wild trout (for the fishing club) and to enhance the biodiversity and

conservation value of the reach

Requirements

• Low cost: no budget allocation

• Non-technical: site was not easily accessible with machinery and only materials available

adjacent to the river could be used

• Aesthetically acceptable:long established (100yrs) fishing club was involved

• Easy to modify if needed

Work was “guided” by the river and the materials available

Reintroduction of large wood: River Bure

Equipment:

• Chainsaws

• A hand winch

• An old plastic boat

… and some volunteers

Methods:

• Trees were felled into the river

• Once in the river, some wood units were modified to comply with EA by-laws or to

accommodate the casting of a fly

• In most cases material was left to self-anchor, but in a few cases branches and trees were

fixed in place

Hydrogeomorphological research on the Bure

Hydrogeomorphological research at the River Bure has been funded by the Hydrogeomorphological and Biogeochemical

Processes Research Theme, School of Geography, Queen Mary, University of London; and University of the West of England

(Chris Parker: Early Career Researcher Starter Grant)

Continuous monitoring

• River stage (and Q, through calibration)

Time-integrated sampling:

• Suspended sediment

Repeat field surveys:

• Channel topography

• Flow velocities and water depths

• Channel substrate type

• Depth of fine sediment

• Position of wood structures

• Aquatic vegetation types

Experimental process-based research:

• Fine sediment transfer/storage

Reach A: Wood reintroduced Autumn 2008

Reach C

Reach A

100m

Reach B

Flow direction

Reach B: Wood reintroductions in Autumn 2010

Reach C

Reach A

100m

Reach B

Flow direction

Reach C: No wood reintroductions

Reach C

Reach A

100m

Reach B

Flow direction

BA CMean: 0.57 mSD: 0.19

Skewness: 0.2

Kurtosis: -0.4

Mean: 0.48 m

SD: 0.18

Skewness: 1.8

Kurtosis: 4.3

Mean: 0.45 m

SD: 0.14

Skewness: 0.8

Kurtosis: 0.7

Summer 2010

BA CMean: 0.50 mSD: 0.20

Skewness: 0.1

Kurtosis: -0.4

Mean: 0.41 m

SD: 0.17

Skewness: 1.6

Kurtosis: 3.3

Mean: 0.39 m

SD: 0.14

Skewness: 1.1

Kurtosis: 1.6

Spring 2010

Water depth

Flow velocity (Summer 2010)

BA CMean: 0.13 m

SD: 0.13

Skewness: 0.8

Kurtosis: -0.06

Mean: 0.03 m

SD: 0.03

Skewness: 1.77

Kurtosis: 3.91

Mean: -0.01 m

SD: 0.03

Skewness: 0.05

Kurtosis: 1.78

Mean: 0.12 m

SD: 0.12

Skewness: 0.56

Kurtosis: -0.08

Mean: 0.02 m

SD: 0.03

Skewness: 2.12

Kurtosis: 5.39

Mean: -0.01 m

SD: 0.05

Skewness: -4.76

Kurtosis: 32

Mean: 0.14 m

SD: 0.16

Skewness: 0.79

Kurtosis: -0.59

Mean: 0.03 m

SD: 0.05

Skewness: 2.02

Kurtosis: 3.82

Mean: -0.01 m

SD: 0.05

Skewness: -2.02

Kurtosis: 10.75

A B C

Substrate characteristics (Summer 2010)

Patchiness associated with

wood structures and aquatic

macrophytes

Homogeneous silt and sand Patchiness associated with

aquatic macrophytes

Aquatic plants

• Similar numbers of species in both shaded reaches

• Variations in patchiness and spatial organisation

• Complex assemblages of plants around wood structures

Spring 2010

Summer 2010

Outcomes so far…

• The fishing club are pleased - they have been catching more wild trout and they see the

benefit in the “natural” habitat that has been created.

• The general view is that the project has been successful in increasing habitat complexity

and fish populations, and emerging results from the research study seem to be confirming

this.

• The project demonstrates the potential for effective, low cost, non-technical approaches to

river restoration by focusing on natural processes, within the right context.

• Dave Brady was awarded the Orvis Wild Trout Trust Conservation Award

(amateur category) in 2010.

Future work

• Fieldwork in spring and summer 2011 will provide post-rehabilitation data for Reach B

The aim is to continue the monitoring over longer timescales to explore:

• Trends in habitat complexity

• Interactions between wood accumulations and hydromorphological processes under

modified conditions

• Mobility/ stability of wood accumulations

• Relationships between large wood, hydromorphological processes and ecology

Links with complementary research by Carl Sayer and Murray Thompson (UCL), Steve Brooks (Natural

History Museum) and Guy Woodward (QMUL): invertebrate and fish diversity, colonisation experiments,

analysis of food webs.

Thank you

Post-project appraisalof the morphological and ecological performance of the River Harbourne flood alleviation scheme near Harbertonford, Devon

Kayleigh Wyatt & Colin Thorne – University of Nottingham

Presentation structure

Introduction

Context and overview of study site

Harbertonford and the flood alleviation scheme (FAS)

Post-project appraisals (PPAs)

Ecological and morphological performance of FAS

Wider applicability

Knowledge gained – SWOT analysis

Lessons learned – summary conclusions

Introduction

Environmentalism has enhanced awareness of human interaction with natural environments

Increasing demand for environmental sensitivity is reflected in flood risk management legislation

EU Habitats Directive (1992)

EU Water Framework Directive (2000)

Foresight Future Flooding Project (2004)

DEFRA ‘Making Space for Water’ (2004)

Pitt Review and Foresight Update (2008)

Floods and Water Act (2010)

Locational context

0 1km

N

Catchment context

(Bradley, 2005)

N

1km0

HARBERTON

HARBERTONFORD

River Harbourne

HarbertonStream

YeolandsStream

(after BDB Associates, 2001)

1998

(Environment Agency, 2003; Environment Agency, 2001, p.45)

Overview of FAS

“reduce the frequency of property flooding at Harbertonford ... without undue environmental disruption and if possible with some environmental gain” ...whilst minimising maintenance requirements and retaining amenity value

Overview of FAS

(Bradley, 2005)

‘the future of flood defence schemes’Sir John Harman (Chairman of Environment Agency)

Post-project appraisals

LEGEND: published paper ; unpublished dissertation ; in progress

Bradley et al.(2004)

Williams (2002)

Breton (2003)

Bradley(2005)

Rhodes(2007)

Wyatt (2010)

Wyatt (2011)

Environment Agency (2011)

EA-DEFRA Project SC040015River Sediments and Habitats

FRMRC (2011)

Calrow(2012)

EPSRC EP/FP202511/1Morphology, Sediments and

Habitats Work Package

MScMScMSc

MSc BSc BSc

N

Post-project appraisals (cont)

(Wyatt, 2010)

0 1km


ECOLOGICAL DATA

River habitat surveys (RHS) – HQA and HMS

Diatom sampling – TDI, GDI and %PTV

Benthic macroinvertebrate sampling – BMWP

Riparian vegetation surveys – species/area

MORPHOLOGICAL DATA

Cross-sectional channel profile surveying

(Wyatt, 2010)


UPSTREAM REACH – 1

Project aim: flood storage and environmental enhancement

Appraised by:

River habitat surveys

(Wyatt, 2010)




Appraised by:


Diatom sampling

(Wyatt, 2010)




Appraised by:


Diatom sampling

Riparian vegetation surveys

(Wyatt, 2010)

Mean average number of flora species per quadrat: 5.71


MIDSTREAM REACH – 2

Project aim: no active management influences

Appraised by:


(Wyatt, 2010)

MIDSTREAM (CONTROL) REACH – 2




Appraised by:


Diatom sampling

(Wyatt, 2010)





Appraised by:


Diatom sampling

Riparian vegetation surveys

(Wyatt, 2010)




DOWNSTREAM REACH – 3

Project aim: enhanced conveyance and amenity, reduced maintenance

Appraised by:


(Wyatt, 2010)




Appraised by:


Diatom sampling

(Wyatt, 2010)




Appraised by:


Diatom sampling

Benthic macro-invertebrate sampling

(Wyatt, 2010)




Appraised by:


Diatom sampling

Benthic macro-invertebrate sampling

Riparian vegetation surveys (Wyatt, 2010)



ALL REACHES

Project aim: maintain natural morphological dynamism of channel

Appraised by:

Cross-sectional channel profile surveying

(Wyatt, 2010)

Knowledge gained

(Harbertonford Community, n.d.)

STRENGTHS Success in achieving FAS project aims,

particularly avoiding environmental disruption and promoting gains

FAS appears to have achieved beneficiary community acceptance –role of stakeholder involvement?

(Harbertonford Community, n.d.; Morris et al., 2004)

Knowledge gained




WEAKNESSES Anecdotal evidence of reliance on

human action during flood events Constraints remain in place (such as

flood walls in downstream reach) Excessive caution in design (such as

over-planting in upstream reach)

Knowledge gained

(Harbertonford Community, n.d.)








OPPORTUNITIES Multiple PPAs of FAS performance to

date – availability of pre-project data Possibility of broader future PPAs

regarding stakeholder involvement Potential for ‘localism’ involving

beneficiaries in FAS maintenance

Knowledge gained








OPPORTUNITIES Multiple PPAs of FAS performance to

date – availability of pre-project data Possibility of broader future PPAs

regarding stakeholder involvement Potential for ‘localism’ involving

beneficiaries in FAS maintenance

THREATS Inadequate FAS maintenance Risks posed by invasive species Future impacts of climate change Future impacts of land use change Inappropriate knowledge transfer to

other flood alleviation schemes

Lessons learned

River Harbourne FAS demonstrates ambition can be rewarded, as it is possible to meet targets for flood defence, environmental enhancement and stakeholder acceptance simultaneously

Acceptance and support from beneficiaries and residents illustrates the advantages of early and effective stakeholder consultation and involvement

However, leaving physical constraints in place has increased the vulnerability of environmental gains to the effects of future climate and land-use changes

Lessons learned (cont)

Performance to date suggests that designers were excessively cautious in over-planting the flood storage area and over-sizing rock used to construct riffles

FAS has reduced need for maintenance but is notmaintenance free – there is no guarantee that riparian stakeholders have the knowledge, skills or resources necessary to meet future maintenance needs

Collection and archiving of pre-project data, coupled with repeated PPAs, provides quantitative evidence concerning FAS performance and makes it possible to learn lessons and manage adaptively

Acknowledgement

The research reported in this presentation was conducted as part of the Flood Risk Management Research Consortium with support from:

Engineering and Physical Sciences Research Council

Department of Environment, Food and Rural Affairs / Environment Agency Joint Research Programme

United Kingdom Water Industry Research

Office of Public Works Dublin

Northern Ireland Rivers Agency

www.floodrisk.org.ukEPSRC grant:

EP/FP202511/1

References and resources

BDB Associates. (2001). Geomorphological audit of the Harbourne catchment. BDB Associates: Exmouth, UK. Bradley, W., Jones, M. & Morrison, A. (2004). Integrating design with the environment to maximise benefits from a flood

storage dam: successful implementation at Harbertonford. In: Hewlett, H. (ed). Long-term benefits and performance ofdams. Thomas Telford: London, UK.

Bradley, W. (2005). Effective flood alleviation design and construction. Proceedings of the Institution of Civil Engineers.Municipal Engineer 158 (ME2): p.107-113.

Breton, N. (2003). Testing and analysis of an enhanced geomorphological post-project appraisal, by its application to theRiver Harbourne flood defence scheme, Harbertonford, Devon. Dissertation for Environmental Management MSc at TheUniversity of Nottingham.

Environment Agency. (2001). Harbertonford Flood Alleviation Scheme: Option Appraisal Report. Halcrow UK: Exeter, UK. Environment Agency. (2003). Harnessing the Harbourne. A flood defence scheme for Harbertonford. Environment

Agency: Exeter, UK. Harbertonford Community. (n.d.). Harbertonford Community website [online]. Available at: http://www.harbertonford.

org/index.php/Main/HomePage. [Accessed 1st April 2011]. Morris, J., Hess, T., Gowing, D., Leeds-Harrison, P., Bannister, N., Wade, M. & Vivash, R. (2004). Integrated washland

management for flood defence and biodiversity. English Nature Research Report 598. Cranfield University: Silsoe, UK. Rhodes, C. (2007). Assessment of the efficacy of one-shot monitoring for a geomorphological post-project appraisal: a case

study of the Harbertonford flood defence scheme, Devon. Dissertation for Environmental Management MSc at TheUniversity of Nottingham.

Williams, L. (2002). The incorporation of habitat parameters to the geomorphological appraisal of the Harbertonford flooddefence scheme, South Devon. Dissertation for Environmental Management MSc at The University of Nottingham.

Wyatt, K. (2010). The impacts and success of the River Harbourne flood alleviation scheme near Harbertonford, Devon.Dissertation for Geography BSc (Hons) at The University of Nottingham.

natalie angelopoulos prof ian cowx hull international ... conference/session 3a...natalie...

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