Llyn Padarn, Llanberis

Last updated May 2016

Work to improve water quality

High levels of nutrients such as Nitrogen and Phosphorus are known to cause problems with water quality in lakes. Our investigation showed that Dwr Cymru/Welsh Water’s network in the area was the main source of harmful nutrients in Llyn Padarn.

We have already imposed conditions on Dwr Cymru/Welsh Water’s permit to discharge sewage effluent to Afon y Bala so far fewer nutrients now enter the lake. DCWW has also improved its network in the area so that there are fewer storm discharges from the sewer system. We also identified more significant work that DCWW needed to do to further improve the quality of the lake. DCWW have confirmed plans to make significant improvement to their sewage treatment works and network. This work is currently underway and will be completed over the next 18 months. When complete the work will further reduce the nutrients entering Llyn Padarn which will further improve the quality of the lake for the public and its wildlife.

Llyn Padarn has now been designated as Wales's only freshwater bathing lake and the results of samples taken by Natural Resources Wales there in 2015 have reached the highest "excellent" standard.

Working to save the Arctic Charr

Arctic Charr numbers in Llyn Padarn have been declining. The exact reasons for this are not fully understood, and similar declines have been reported in 10 out of the 11 lakes in England and Wales that host natural populations of Charr. The effects of climate change along with site specific issues are thought to be a significant factor in such declines.

Alongside the work to improve water quality in Llyn Padarn, a programme to breed young fish in captivity has also been set up.

Each year, NRW officers catch and strip the eggs from some Arctic Charr and breed the fish at our hatchery.

Some are released back into Llyn Padarn while others have been released into Llyn Crafnant in the Conwy Valley to establish a back-up population.

Watch a video taken in December 2014 of how we do this

Watch our video of work done in November 2018 to conserve Arctic Charr

We use cameras to monitor their numbers and activity but as the Charr normally migrate to their spawning grounds in the hours of darkness, getting good quality images is difficult.

However, in December 2014 our monitoring cameras captured a shoal of Arctic Charr approaching their spawning grounds in Afon Y Bala during daylight hours for the first time.

It's also encouraging that this shoal includes a mixture of Charr which have been fin-clipped - which means we released them into the lake - and non-fin-clipped - which means they were born naturally in the lake.

It's too early to draw any conclusions from this for the future of the Arctic Charr population at Llyn Padarn, but it is cause for optimism that the Arctic Charr still has a future in the lake.

Effects of Dinorwig power station

Along with other pressures such as climate change, algal blooms associated with higher nutrient levels in Llyn Padarn up until the mid-1990’s and angling pressure since the 1980s, another important factor in the decline of the Arctic Charr is likely to be the loss of their spawning grounds in Llyn Peris when the Dinowic Power Station was built in the 1970s and 1980s.

We are working closely with First Hydro - the operators of Dinorwic Power Station - and Gwynedd Council to identify opportunities that will enable the creation of a much bigger area of suitable habitat in the Afon y Bala where Charr can successfully lay their eggs during the breeding season.

The effects of occasional water temperature “spikes”, caused by water releases from Llyn Peris, on spawning and egg development have also been studied. This showed that the spawning grounds are generally upstream of these releases and do not experience any increase in temperature.

Fish Legal’s judicial review challenge

In February 2012 the Seiont, Gwyrfai and Llyfni Anglers’ Society legal advisers claimed that discharges of sewage into Llyn Padarn, a Site of Special Scientific Interest, had caused damage to Arctic Charr and to the surface waters of the lake.

Following an investigation we notified Dŵr Cymru Welsh Water (DCWW) in 2013 that its waste water collection and treatment had caused environmental damage to Llyn Padarn.

Subsequently, the Society brought a judicial review challenging the basis of our decision, which was made under the Environmental Damage (Prevention and Remediation) (Wales) Regulations 2009. These transpose, in Wales, the European Union’s Environmental Liability Directive with regard to the prevention and remedying of environmental damage.

This was settled by consent, details of which were set out in a Consent Order and approved by the Court in May 2014. As part of this, we agreed to quash our original decision and confirmed that in our fresh consideration of the issue, we would take into account all environmental damage arising after 30 April 2007 (the date by which the United Kingdom was required to implement the Directive). Our first investigation considered all damage arising after 6 May 2009 (the date on which the Regulations came into force).

On 15 December 2014 we published a fresh decision document taking into account our new findings. This again found that the sewage treatment works (owned by DCWW) played a major role in causing environmental damage to the lake. The damage also contributed to the algal bloom in 2009 which forced the closure of the lake as a safety precaution. However, it also concluded that there was no environmental damage as defined by the Regulations to the Arctic Charr population which was in decline before 2007.

The Seiont, Gwyrfai and Llyfni Anglers’ Society took NRW to judicial review on November 24/25 regarding this decision document and we are currently awaiting judgement and will respond once we have considered its contents.

Snowdonia Pumped Hydro

Snowdonia Pumped Hydro limited originally applied to Gwynedd Council for planning permission for a 49,9Megawatt pumped storage facility, which was granted in February 2014.

We were consultees in the process and provided advice on amenity, fisheries, landscape, historic landscape, access and recreation as well as biodiversity and protection of wildlife.

Since then, the company has opted for a larger scheme of 99.9Megawatts. This is above the threshold that Gwynedd Council can consent, so the application will be made through the Development Consent Order Planning process, and determined by the UK Government.

The company has carried out pre-application consultation locally, and has submitted its application to the Planning application. NRW, as a statutory consultee, is providing comments on the formal application to the Planning Inspectorate.

In addition to planning consent from the Planning Inspectorate, Snowdonia Pumped Hydro also needs abstraction and discharge permits from NRW before they could operate.

Abstraction licence

We received an application for an abstraction licence in February 2015 and carried out a consultation process.

We carried out an in-depth assessment into the company’s proposals to find out if the water could be taken from Llyn Padarn with minimal impact on the environment. Our investigations showed that the company’s proposals to abstract the water would not cause environmental damage, therefore we granted the permit in July 2015. This allows Snowdonia Pumped Hydro Ltd to abstract water from Llyn Padarn, to a reservoir at Glyn Rhonwy. It contains conditions to protect the local environment. These include daily limits on the amount of water that can be abstracted, a block on abstracting water if levels in the River Seiont – an important fishing river – become low, and erecting underwater screens to prevent fish getting in to the system.

Steps we follow when deciding whether to grant or refuse a license.

The steps are defined by legal requirements. We are required to justify any decision within the confines of these legal limitations. Local opposition to a development is not, in itself, a reason for us to refuse an application.

In making our determination, we will consider all relevant information submitted to us. However, many of the comments we have received refer to matters which are beyond the remit of our determination. Amongst the issues we consider when reaching our decision are:

  • the environmental effects of the proposal and its impact on designated sites and habitats
  • the likely effect of the proposal on the protected water rights of existing licence holders and other lawful water users
  • the reasonable requirements of the applicant for water and its efficient use
  • the sustainability of the proposal and any effects on biodiversity

Among the issues we cannot consider are:

  • Noise
  • Dust
  • Location
  • Transport
  • Impacts on wildlife beyond the immediate effects of the proposed abstraction
  • Future connections to the national grid
  • Impact on recreation
  • Visual impact
  • Cultural heritage
  • Construction impacts
  • Rights of way

These issues are beyond the scope of our permit determination process and many will be considered by the Planning Inspectorate as part of its determination of the Development Consent Order application.  

The applicant will also need further permits from NRW such as environmental permits for discharges and consents to work in a Site of Special Scientific Interest (SSSI).

Discharge consent

We received an application for discharge consent from Snowdonia Pumped Hydro, and we consulted publicly on this - closing date was 9th November 2016.

On Friday 6 December 2017 NRW issued environmental permits, which allow Snowdonia Pumped Hydro to carry out proposed water discharge activities into Llyn Padarn and Nant y Betws in Llanberis to operate a pumped storage facility for the hydro-electric scheme at Glyn Rhonwy.

The permits are issued with strict conditions to protect the environment.

The types of things we considered as part of this decision are effect on water quality in Llyn Padarn, effect on SSSI and SAC features of Llyn Padarn, impact on fish and water temperature.

The restrictions on what we can consider are similar to those for the abstraction licence.

Advice re lagoons to Gwynedd County Council

In our response to the Planning Application submitted to Gwynedd County Council, we gave specific advice on how best to protect the local environment and the recreation facilities in the area. Taking this advice on board as part of the planning process is a matter for the planning authority.

Exploratory drilling

Ground Investigation works were carried out by Snowdonia Pumped Hydro from March to July 2015 to explore the ground conditions within the vicinity of the proposal.  This activity falls within the remit of the planning authorities.


Peregrine Falcons are present near the development. The recent ground works have been overseen by an independent Ecological Clerk of Works, and has been subject to its own Construction Environmental Management Plan. A site visit by our officers in June 2015 to check on these birds confirmed that they were behaving normally.

Upper Access Road – Chwarel Ddu

Construction traffic movements are within the remit of the Highway Authority, Gwynedd Council.


Investigations on the potential for munitions within the confines of the development are on-going. We continue to test local water quality for signs of munitions in the water.

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