Final Water Quality Sondes Installed at Llyn Cwellyn

Meteor Communications installing sondes

As we reach the end of our Prosiect Torgoch, supported by The National Lottery Heritage Fund, we have completed a major milestone in our mission to safeguard one of Wales’s most remarkable fish – the Eryri Torgoch (Arctic charr) of Llyn Cwellyn.

This week, in collaboration with Meteor Communications, our team installed the final set of real-time water quality sondes that will monitor the lake. These instruments provide continuous, high-resolution data that is essential for understanding the pressures faced by this rare species.

Each sonde holds multiple probes, allowing us to measure a range of water quality parameters such as pH, dissolved oxygen, conductivity and temperature.

The pH challenge

We have identified upstream pH fluctuations that create stressful and sometimes harmful conditions for the fish, especially during sensitive life stages such as spawning and early development. Heavy rainfall events wash acidic water from the upper catchment into the lake, causing sudden drops in pH that can be difficult to detect without continuous monitoring.

The new sondes allow us to track these rapid changes hour by hour, giving us the evidence needed to plan interventions and advocate for better catchment management.The sondes track rapid changes hour by hour and help us understand whether our catchment interventions are improving conditions in the lake.

Stephen from Meteor Communications installing solar panels so we can retrieve live data.

Working across the catchment

Protecting the Torgoch goes beyond monitoring the lake itself. Throughout Prosiect Torgoch, we have worked with landowners, farmers, foresters and local partners across the upper catchment to slow the flow, reduce sediment, and improve water quality before water reaches Llyn Cwellyn.

Angharad and Stephen on the banks of Llyn Cwellyn

The final installations mark the completion of our water quality monitoring network. Working with Meteor Communications, we installed sondes capable of measuring:

• pH

• Temperature

• Dissolved oxygen

• Conductivity

• Turbidity

These parameters are essential for tracking the conditions that Arctic charr experience throughout the year. The information gathered will guide our future restoration work and help protect Llyn Cwellyn’s unique ecology.

A legacy for the future

As Prosiect Torgoch phase one approaches its conclusion, these sondes represent a lasting legacy. They will continue to support conservation, research and evidence-based decision making long after the project ends. Their data will help ensure that threats to the Torgoch can be identified quickly, understood clearly and acted upon effectively.

We are grateful to The National Lottery Heritage Fund for supporting this work, to Meteor Communications for their expertise, and to the many farmers, foresters, volunteers and partners who have contributed to protecting the Torgoch’s home.

The story of Llyn Cwellyn is still unfolding, but thanks to the commitment of our funders and community, the future of the Eryri Torgoch looks brighter.