As part of Prosiect Torgoch we will be delivering a comprehensive water quality monitoring programme at Llyn Cwellyn, thanks to the National Lottery Heritage Fund. The lake is located near Rhyd Ddu below the summit of Eryri and contains one of only three natural populations of torgoch (Arctic charr) in Wales.

Llyn Cwellyn provides the best habitat for Torgoch in Wales, but in recent years there has been a gradual decline in water quality. Nutrients entering the lake have increased, resulting in a decrease in deepwater dissolved oxygen. Arctic charr require cool, well oxygenated waters to survive, and the deepwater zones of lakes provide a refuge from warm summer temperatures and are critical for their resilience against climate change.

With the support of Goldsmith Ecology and a team from The University of Liverpool we will soon be undertaking a palaeoecological study. The work will involve extracting a sediment core from the deepest point of the lake which will then be dated and analysed to understand how nutrient levels have changed over the last century.

A second aspect of the water quality programme will be to deploy sondes in the catchment upstream of Llyn Cwellyn to better understand nutrient sources. Sondes are remote instruments that can continuously measure and log nutrient concentrations over many months.

Once the water quality monitoring programme has been completed, we will be working with local stakeholders to try and reduce nutrients entering the lake. The objective is to secure Llyn Cwellyn as a viable, long-term sanctuary for torgoch in Wales.