gauging weirs - addressing the needs of different stakeholders

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Gauging Weirs - Addressing the needs of different stakeholders

Dr Di Hammond

Senior Projects Advisor


Overview

• Why do we need to measure flow?

• Who uses flow data?

• Other considerations

• Why use a structure?

• Dis-benefits of structures

• What are the alternatives?

Why do we need to measure flow?

• Strategic

– Long term trends

– Climate change

• Operational

– Flood

– Drought

– Water resource management


Who Uses Flow Data?

• Water resource managers

• Flood defence managers

• Water companies

• Academics and students

• Policy makers

• Climate change scientists

• River restoration practitioners


Some Other Considerations • Archaeology

• Subsidence

• Water level maintenance

• Aesthetic appearance


Why use structures to measure flow?

• Accuracy with a Weir Structure – Larinier fish pass 3%

– Crump and flat v weirs 3-6%

– V Notch thin plate weir 6%

• Structureless measurement techniques accuracy – Multi path time of flight ultrasonic gauges 7-10%

– Doppler flow gauges 10%

– Electromagnetic flow gauges 10 – 15%

– Open channel 10%plus


The Dis-benefits of structures

• Geomorphological effects

• Fish passage

• Habitat

• Flow variability

• Flood issues


What are the structureless alternatives for flow measurement?

• Ultrasonic

• Doppler flow gauge

• Electromagnetic

• Open channel



Scaling up our Aspirations for River Restoration and

Management

14TH ANNUAL NETWORK CONFERENCE

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gauging weirs - addressing the needs of different stakeholders

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