how appraisal of nfm options could be used to deliver and
TRANSCRIPT
How appraisal of NFM options could be used to deliver and prioritise investment in upland peat restoration
Alex Jones and Steve Rose
Introduction
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Structure
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What Can Peatland Restoration by itself Deliver?
Extract from: Working with Natural Processes Evidence Directory (EA, 2017)
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Big Gullies = Big Flows?
The Wyre
The Wyre
Data Gathering
What’s a Gully – What’s a Stream?
Historic Maps vs Current Maps
Mapping watercourses
On-site Surveys
Conceptualisation
Landscape Conceptual Model
Example Landscape Features
NFM Opportunities
NFM Intervention Types
Potential NFM Locations
NFM Modelling
Aims
Scales
Surface Water Flood Model
• Rainfall event hyetograph dropped onto
2m bare earth DTM of catchment and
allowed to flow downslope
• Model permits soil losses (infiltration) to
reduce through event as soil gets wetter
• Hydraulic roughness (friction) grid
related to vegetative cover (e.g.
heather, bare peat, grasses)
• Baseline (no change) model runs
• After change (with NFM) model runs
Flow
Test Catch-ments
UAV DroneSurveys
Model Improvements
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Flo
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m3
/s)
Time (h)
Hawthornthwaite Total Flow Catchment Baseline Model
Catchment Model with Gullies
Test Catchment Baseline
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Flo
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m3
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Time (h)
Tarnbrook (121) Catchment Baseline Model
Catchment Model with Gullies
Test Catchment Baseline
Effect of microtopographic features on peak flow
Hawthornthwaite – 35%
Tarnbrook – 19%
NFM Options Assessment
NFM Model Results
Most effective when targeting:
- Larger flow paths- Connecting Gullies/ Streams- Infill and divert to adjacent land surface
Caveats – Availability of infill material
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Flo
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m3
/s)
Time (h)
Left Bank Tributary (134) Test Catchment Baseline
Infill Scenario
NFM FeatureModelling
Whole Catchment Ranking of NFM Potential
Multiple Objectives
NFM and Multiple Objectives
• Bare peat, grips, gullies, vegetation management
• Start peat regeneration where conditions permit
• Create mosaics – bog pools and flushes
It’s in our hands!
Conclusions
Conclusions
• Low Tech methods – mapping/air photos
• High Tech methods – modelling
Project Contacts
Thank you for listening!
Any questions
out there?