Use of a multi-disciplinary approach to adjust an abstraction regime - - PowerPoint PPT Presentation

Use of a multi-disciplinary approach to adjust an abstraction regime for the protection of shad Nicola Teague & Tom Elmitt

IFM Fish and Flows Specialist Conference 2019 - York

Background to the project

Project structure

Hydraulic modelling and Bathymetry T&F group Ecology impact T&F group Licencing T&F group

Steering group

Flow of information and decision making General process of work

• Nantgaredig Raw Water Pumping station

abstracts up to 200 Ml/d a day from the Tywi to the Lower Lliw

• It is subsequently reabstracted from the Lower

Lliw for treatment at Felindre WTW, which is the largest WTW in Wales.

• From Felindre it supplies areas across South

Wales, from Carmarthen in the West to Cardiff in the East.

Purpose of the abstraction

• Part of the Tywi regulation scheme – Llyn

Brianne is ~ 64,000 Ml reservoir in the

• headwaters. Water is released from the dam at

a rate of 200 Ml/d and runs down the river for >40 miles.

Insert picture of Brianne

Asset limitations

• Fixed speed high lift pumps
• Minimal variability in low lift pumps
• Small bankside storage
• Lliw storage must be preserved for resilience
• High lift pumps can only run two at a time
• Felindre demand must be met at all times

Project outcomes

• Ended up agreeing on conditions which satisfied both sides
• Beyond reasonable scientific doubt that there is no adverse impact
• Licence is workable for DCWW and NRW
• Licence required no additional infrastructure for compliance