Natural Flood Management in the Tweed Catchment

Drivers

• Statutory duty under the Flood Risk Management (Scotland) Act 2009 to promote sustainable flood risk management

• Consequential interest in taking forward research into NFM techniques and measures

• Development of Flood Protection Schemes with NFM considered as part of the solution.

• Solution to sediment management problems

• Response to extreme flood events in a rural area

• Climate change and need for increased resilience

• Obvious synergies between WFD delivery, improvement of designated site, LBAP etc.

• Potential Multiple Benefits – improvement to water quality, fisheries, tourism, landscape, soil conservation, carbon sequestration etc.

Natural Flood Management projects in the Tweed catchment

The Bowmont Water Project

1 Structure

Mean elevation change: +0.13 mSediment volume change: +98.7 m3

Responses to Sept 2012 flood : Bar 2

Net change: + 5.9 m3

Aug 2012 Oct 2012

Eddleston Water Project

Background - Why Eddleston?

• Scale – 70 km2• Variety of land use types• Good source-pathway-receptor model• Substantial modification over time – ‘bad’ status• Flooding issues in Eddleston and Peebles

Core aims

• investigate the potential of reducing the risk of flooding to the communities of Eddleston and Peebles by restoring natural features within the catchment.

• improve the river habitat for wildlife and fisheries;

• work with landowners and communities in the Eddleston valley to maximise the benefits they would gain from such work, while maintaining farm business productivity/profitability.

Ancillary aims, objectives and opportunities

Act as test bed for a raft of different policy areas including:

- Improvement of a water body under the RBMP and WFD- Practicalities of delivering NFM under the Flood Risk

Management Act- Improvement of an SAC/SSSI- Improvement of a world class fishery and mainstay of the local

economy- Understanding the contribution of groundwater flows to

flooding- Climate proofing - increasing farm/community resilience to more

extreme climatic events- Woodland expansion in a working landscape- Carbon sequestration and payment for ecosystem services- Understanding and overcoming barriers in engaging land

managers- Land Use Strategy planning using ecosystem services approach

A partnership approachThe project is coordinated by Tweed Forum and involves the following organisations in terms of management, research, advice and funding.• Scottish Government• SEPA• Scottish Borders Council• Dundee University• British Geological Survey• Forestry Commission• SNH• NFU Scotland• The Tweed Foundation• Forest Carbon• The Woodland Trust• CEMEX Ltd• The Environment Agency• Scottish PowerAnd many land owners and farmers.

Achievements to date – Scoping Phase

Monitoring network – establishing the baseline and measuring impact

• Surface water• Groundwater• Ecology - fish, invertebrates,

macrophytes• Ecosytem services• Economic

Works on the main stem (pathway section) –Historic planform

Roy Military Survey circa 1750

Toll road map 1792

Achievements to date – practical works

Today’s planform

Re-meandering

Source areas – planting

Ruddenleys. 17ha tree planting, 3 large ponds, 12 log jams

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Wester Deans 2500m of transverse hedges and 3 flood retention ponds

Flow restrictors/debris dams

Middle Burn – 10 log jams

Craigburn root wads

Craigburn. Re-profiling 300m and 34 log jams over 800m

Summary of practical outputs and outcomes

• 66 hectares of riparian woodland created• 16,000 metres of fencing erected• 1.8km of river re-meandered• 56 ‘flow restrictors’ installed• 19 leaky ponds created (7000 square

metres)• Over 70,000 trees planted• 23,000 tonnes of carbon sequestered (over

100 year period)• Waterbody status under WFD has gone

from ‘Bad’ status to ‘Moderate’.

Funding ......for work on the ground

• Interventions on 17 different farms amounting to some £600k

• Public sector – Scottish Government, Water Environment Fund, SRDP, Scottish Borders Council.

• Private (and charitable) sector – Forest Carbon, CEMEX, Woodland Trust, Scottish Power and land owner contributions.

• Considerable added value and leverage for individual funders

Role of Tweed Forum

• Trusted intermediary and facilitator• Overcoming barriers to

participation – engaging land managers• Ensuring the right measures, happen in

the right place.• Achieving critical mass – involving

multiple land owners to achieve impact at the catchment scale

• Securing funding package and overseeing all works

• Promoting and communicatingmultiple benefits

Critical mass and multiple benefits

Achieving multiple benefits

Monitoring network• 11 stream gauging stations (Dundee)+ 2 (Forest Research) +2SEPA• 4 x Tipping Bucket Rainfall• Groundwater and hillslopemonitoring(BGS Darnhall Mains)

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Main stem rated streamflow record (Eddleston Village)

Æ Interventions

Baseline period

Flow generation analysis – high flow events

• High flow event captured in rating Gauges (ADCP)• Areas responsible for rapid flow Response identified + insights into routing• 22nd June 2012 – highest event on

record – excellent test of catchment response

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Tributaries - debris flow deflector studies

• Wood deflectors installedMay 2013 (Forest

Enterprise)• Hydraulically modelled• Predict effects of high flow

event, e.g. 1 in 25 year Æ Small peak attenuation, Ædelay of ~1hr in peak wave

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