For more than 120 years, water for 80,000 homes and businesses in and around the towns of Egremont, Cockermouth and Whitehaven has come from local sources. But the waterbodies are also home to many rare and protected species.  The risk to wildlife, along with the growth of the population means we had to find sources other than Ennerdale Water, Crummock Water, Overwater and Chapelhouse Reservoir.

We worked with environmental stakeholders including the Environment Agency and Natural England and stopped using these water bodies as a water source at the end of March 2023.

Our West Cumbria abstraction licences are now permanently withdrawn as the new water network is operational and uses Thirlmere Reservoir as the water source.

Bringing water to the 80,000 homes and businesses via the new 62-mile long pipeline from a more strategic water source, Thirlmere reservoir, means we can better meet the demands now and for future population growth, while also protecting the very precious local environments by not taking water from these smaller sources. 

We also have a legal agreement between ourselves, Natural England, Environment Agency and DEFRA (Department for Environment, Food and Rural Affairs) under the Habitats Directive to cease abstraction from these water bodies and carry out the work as required under this project.

The legal agreement referred to is the compensatory measures legal agreement, which secures all the compensatory measures for the potential environmental damage caused by the Ennerdale abstraction.  Revoking the abstraction licences and removing the abstraction related infrastructure are all compensatory measures as part of the Ennerdale IROPI (imperative reasons of overriding public interest) case.

We have undertaken significant investment over the past 15 years and continue to do so, to enable more water to be moved around our network regions more readily. 

An example of one of these projects is the West East Link Main that connects Liverpool to Manchester, enabling Manchester to be supplied by alternative sources and is therefore less dependent on Thirlmere.

Thirlmere is a large strategic water source and part of our integrated regional water supply system.  We will be using more of the water from Thirlmere to supply homes and businesses in Cumbria and use capacity at other sources in the south of our region to make up the difference. 

Our Water Resources Management Plan (WRMP) sets out how much water we think our customers need, how much we have available and how we will meet that supply and demand between 2026 and 2086. 

Experts assess and model what will affect the demand for water in the future and take into account factors like population growth and the impact of climate change.  Based on those assessments, which have also been subject to scrutiny by a DEFRA appointed planning inspector, Thirlmere's the right solution to meet the needs of the population now, and in the future. 

We must demonstrate to the Environment Agency and Cumberland Council that our assessment of flood risk is in accordance with National Planning Policy and that flood risk to, and from the proposed projects can be managed effectively without increasing risk to others. If we are not able to provide this, taking climate change into account, it's unlikely the project would be able to obtain planning permission.

We've engaged with specialists to carry out extensive hydraulic modelling studies to assess how the proposed work may alter flows. The key findings are detailed below.

Chapelhouse Reservoir and Overwater

Chapelhouse and Overwater reservoirs are not designed or operated as a flood management provision.

The weir at Overwater was designed to retain a larger volume of water than would have been stored in the natural lake.  The dam at Chapelhouse was designed to create a body of water in the natural valley of the River Ellen (that is diverted around, and perched above the reservoir) to then allow water to be abstracted for drinking water purposes. 

Chapelhouse does not route flood waters through it, this is done naturally along the River Ellen.  The reservoir is nearly full all of the time which provides little flood attenuation provision as it acts to store and retain water 'offline' for water supply and abstraction. 

Removal of Chapelhouse does little to change the natural hydrological regime. Our modelling is also assessing the impact for both flow and flood level throughout the catchment down to Maryport. The flood model and flood risk assessment has been reviewed and signed off by the Environment Agency who are satisfied that the proposed scheme will not increase the risk of flooding.

Click the link below to take a look at graphics which help to demonstrate the existing and proposed top water levels at Overwater.

Graphics: Overwater

We understand that these reservoirs are valued spaces and an important landscape for visitors and the surrounding communities.  We're working closely with the Environment Agency, Natural England and our specialist ecology contractor to carry out a wide scope of surveys and assessments.

The projects would deliver several environmental benefits including;

• The restoration of natural salmon habitat
• Removing barriers to fish and eel movement
• Restoring natural flows and sediment transportation
• Habitat enhancement such as tree planting, which form an integral part of our planning applications.

A full suite of ecological surveys have been carried out. This started with initial habitat survey and scoping, which then led to further bat, otter, reptile and invertebrate surveys to make sure that we captured all wildlife concerns and can assess potential impacts and mitigation as part of the planning application.

How will the project impact aquatic plants along the lakeshore?

Over 27 macrophyte species were recorded in Overwater and the most abundant species were widely distributed with rarer species limited to one or two discrete locations.  The survey confirmed that the aquatic macrophyte community for which Overwater was designated continues to include most of the characteristic species noted in the SSSI citation.  Two invasive species Crassula helmsii and Elodea nuttalli were found in abundance and strict biosecurity measures will be required. 

Chapelhouse was recorded to contain 18 macrophyte species.  The most abundant and widespread being the invasive species Elodea nuttalli. 

Many of the macrophyte species growing in Overwater and Chapelhouse are physiologically adapted to cope with seasonal, inter-annual variations in water levels.

So, whilst short-term, inter-annual fluctuations in water level are unlikely to impact significantly on the overall macrophyte composition, it is hard to predict with a high degree of certainty what the long-term impact of a permanent lowering of the water level at Overwater would be.  It is also not possible to say with a high degree of certainty that any observable impact would be small or insignificant.  This is going to have to be monitored.

Removal of the weir and the re-naturalisation into a free flowing stream at Chapelhouse means that macrophytes characteristic of lake habitats will be lost and emergent riverine macrophytes will thrive.  A National Vegetation Classification survey (NVC) of the entire lake boundary has been carried out, along with an underwater macrophyte dive survey of Chapelhouse.

Information on the construction impacts at all of the sites was available at our October 2026 drop-in session and can be viewed here.

We are undertaking other similar schemes within West Cumbria each of which is being delivered to different timescales with varying scope of works, constraints and requirements. For information on these schemes please visit the dedicated project pages at the link below.

• Crummock Water
• Ennerdale Water

We have developed visualisations which are available showing how we expect the site will recover in the short term (1 year) as well as longer term (15 years) following completion. The visualisations are based on the landscaping schemes that are available and will be submitted with the Planning Application together with a long term management plan to secure the delivery of this.

The timescales in the visualisations for the recovery of the site are also based on experience of a similar scheme at Baystone Bank, Millom where the site recovered and was grassed over within a year with established vegetation in a very short period of time.

We hope you have found this information about our proposed long-term plans helpful. We've held several community drop-in sessions and really welcomed your feedback. Thank you to everyone who took the time to come along. 

If you have any queries, please complete our feedback form.