Anglian Water - Fens Reservoir
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Frequently asked questions

Anglian Water and Cambridge Water are progressing plans for a new reservoir in the Fens that will secure water supply to our customers for future generations.

You can play an important role in helping to shape our proposals, so they best serve the needs of everyone.

Below are some answers to questions that have been most frequently asked.

Water is vital to health and wellbeing, to the economic prosperity of the East of England, and to maintaining a thriving natural environment that we can all enjoy.

Yet we face growing challenges to supply. Our region is low-lying, one of the driest in the UK, and especially vulnerable to a changing climate. Drought is set to become more common amid hotter, drier summers, and intense rainfall events are becoming more frequent.

To meet these challenges, we all have to play our part in balancing the needs of society, business, and the environment to enable a sustainable future. We’re already working on new strategic pipelines to move water from wetter to drier parts of our region, installing smart meters in customers’ homes, and driving down leakage.

While all the investments we’re making today will help to keep taps running, the available supply will fall well below the demand for water unless we plan for future resources now. The proposed new reservoir in the Fens has been identified as a large-scale investment in new water resources that we need and will play a critical role in securing water supply long into the future.

Reservoirs contain a volume of water that provides a level of resilience and environmental opportunities that are not provided by other resource options such as desalination or water reuse.

Reservoirs are sustainable ways of producing resilient, safe drinking water supplies because they take water from river catchments when they have surplus water. They mean we can make the most of wet weather for public water supply, capturing river water that would otherwise drain to the sea and storing it so it’s on tap when needed.

When we looked at where we might best build reservoirs across our broader region, we identified rivers in the Fens as having enough water surplus in the winter to supply the reservoir. It will make the most of the available resources and provide water to local communities and businesses across our region, including in Cambridgeshire.

These are the sources that are included in our phase two proposals, shown in the order of which we would draw available water from them:

  • The Middle Level system
  • Either the River Great Ouse or the Ouse Washes (River Delph)
  • The River Nene and its Counter Drain

We’ve evaluated many options including desalination, water recycling, aquifer storage, and water recovery. Our latest plan identifies the new reservoir in the Fens as a crucial investment needed to meet the growing demands on water supplies in the East of England.

You can find out more about how we plan future resources by reading Anglian Water’s Water Resources Management Plan here, and Cambridge Water’s Water Resources Management Plan here, and Cambridge Water’s Water Resources Management Plan here.

The cost of the project will ultimately be funded via water company customer bills, given that our customers will benefit from these supplies. To ensure the best possible value through a competitive process, our regulator Ofwat has proposed delivery mechanisms which involve third party providers delivering and owning these assets.

Our customers can be reassured that we invest every pound in doing the right thing now and for the long term. We believe our responsibility is to them, their communities and to the environment we look after.

The reservoir is part of our long-term plan to ensure we can continue to deliver enough water to local communities and businesses across our region, including in Cambridgeshire.

Half the treated water from the new reservoir is needed by Anglian Water customers, and the other half by Cambridge Water customers. These supply needs are identified in both companies’ Water Resources Management Plans (WRMPs).

You can find out more about how we plan future resources by reading Anglian Water’s Water Resources Management Plan here, and Cambridge Water’s Water Resources Management Plan here, and Cambridge Water’s Water Resources Management Plan here.

We understand that our proposals will have an effect on homeowners, landowners and the nearby community. We’re committed to working with everyone as the project develops and want to hear all views on our emerging proposals.

When we were considering locations for the reservoir, the quality of agricultural land and potential impacts were considered in the site selection process. Given the size of the reservoir, all the sites we have considered had the potential to affect agricultural land.

We recognise that people are concerned about what the project will mean for local businesses and employment and are committed to assessing these impacts as the project develops. The impact on business and employment will be assessed as part of our Environmental Impact Assessment (EIA).

The findings of our EIA work will be consulted on in a future consultation, as part of our Preliminary Environmental Information Report (PEIR) and presented in an Environmental Statement which will accompany our application for consent. The Environmental Statement will include a Socio-economic and Community chapter, which will consider the effect on employment.

The scope of these studies will be agreed with the Planning Inspectorate as part of the formal EIA scoping process. Through these processes we will investigate the potential environmental impacts of the proposed project, together with how we plan to reduce or limit these impacts.

We recognise that, in some instances, homeowners affected by our plans for the reservoirs may need to sell their property, but that the timeline of our proposals raises questions.

We are committed to supporting those affected by our proposals as the project develops. One of the ways we plan to do this is through a residential property support scheme, which could offer support to homeowners, who would like to sell their properties before the project has consent and acquisition of property commences.

While Anglian Water and Cambridge Water are not required to do this, we think it is an important step in providing support for people most affected by our plans.

Our residential property support scheme is now open for applications – to find out more about it and to see if you’re eligible, please read our fact sheet.

We are committed to reducing our carbon production and have a track record in delivering significant reductions. Not only were we the first water company to set targets for reducing capital carbon, but we were also the first company globally to be certified to PAS 2080, the international standard for managing infrastructure carbon.

We are bringing this same focus in how we develop our plans to build and operate the reservoir in the Fens.

We are considering the feasibility of including renewable energy generation as part of the main reservoir site. While the mix and capacity of this is still being explored, we have indicatively suggested at this stage of our emerging design that wind turbines could be located in the area south of the Forty Foot Drain. Find out more by reading our energy and carbon fact sheet and the main site design brochure.

We will consider and develop our designs in line with the findings from our Environmental Impact Assessment, which we are required to undertake as a nationally significant infrastructure project. The EIA process helps us make informed choices that promote sustainable development and protect the environment.

Read more about our approach to the environment below.

This reservoir is recognised as being a strategic regional asset, so much so that it qualifies as a Nationally Significant Infrastructure Project (NSIP). This is due primarily to the volume of water it can hold. We will therefore follow the procedures set out in the Planning Act 2008 which provides the framework for how NSIPs are developed and consented.

We will apply to the Planning Inspectorate, who act on behalf of the Secretary of State for Environment, Food and Rural Affairs (DEFRA), for permission to build the reservoir. The permission is called a Development Consent Order (DCO).

Our application will then be considered by an examining authority made up of one or more planning inspectors during an examination. This is likely to last approximately six months. After examination, the examining authority will issue a recommendation to the Secretary of State who will then make a final decision on whether the project is consented.

Local people and stakeholders have an important role in influencing how the reservoir is developed and designed. During this pre-application phase, we will be consulting with affected landowners, local people, and stakeholders to gather feedback to help shape our proposals before we submit the application for the DCO.

Our summer 2024 consultation is the second phase in a multi-phase approach – at least one more consultation will follow.

The DCO would grant powers to compulsorily purchase land and property required for the project, although our strong preference would be to purchase any required land and property by agreement with the owners. We are directly engaging with those who may be most affected by our proposals.

Click here for more information on the DCO application process

The Regulators’ Alliance for Progressing Infrastructure Development (RAPID) process was set up to develop new strategic water resource solutions. RAPID is made up of the three water regulators – Water Services Regulation Authority (Ofwat), the Environment Agency (EA) and the Drinking Water Inspectorate (DWI).

RAPID assesses proposals for new large-scale, strategic investments to make sure water companies are progressing proposals that best meet their customers’ needs.

This assessment is carried out when companies submit information about their proposals at points in time called ‘gates’. Gate two was in November 2022 and gate three is planned for later in 2024.

One of the key themes coming out of our last consultation was making sure the reservoir was an inviting place to visit. People were keen to see places for activity and recreation, nature and wildlife and many other features that would attract visitors from across the region.

We’ve proposed a bold design as an intentional feature to create interest and excitement – a place we hope people will want to visit. We think it gives interesting opportunities to include a whole range of features – from water sports and footpaths to visitor and education centres that make the most of the bold shape.

Find out more about our reservoir design by reading our main site design brochure.

We completed a multi-stage site selection process to identify the chosen site for the reservoir. This aimed to make sure we identified a location that would be suitable for hosting a reservoir. Through the process we also sought to minimise impacts on nearby areas and communities and meet planning and regulatory frameworks.

The site we’re proposing was found to be the most appropriate for building a new reservoir during our site selection process. On balance, it performed best across a range of the key factors we assessed. It also provides the potential opportunities to deliver wider benefits to the regional economy and neighbouring communities.

Since our phase one consultation, we have been working hard to develop our plans for the proposed site. You can read full details about this here.

The proposed new reservoir in the Fens will have a water surface area of approximately 5km² - around the size of Grafham Water - and will hold up to 55 million cubic metres of water.

Once in operation, it could supply up to 87 million litres of water a day for up to 250,000 homes a year.

We’re seeking to avoid a reservoir with basic, uniform embankment slopes that provide no shelter or integration with the surrounding landscape.

At this stage, we have considered options for planting and features on the embankments that could improve accessibility and appearance.

We estimate that the embankment crest height will be between 10 and 15 meters above existing ground level. In the emerging design the embankments are shown at 12.5 metres. However, these are not fixed at this stage and require further investigation and assessment.

For more information, please read our main site design report below.

We are working closely with the flood authorities who play a fundamental role in managing water and flood risk in the East of England, including the Environment Agency, local councils, and internal drainage boards.

We are focussing on how the reservoirs themselves – including how water is transported to and from them – are designed to cause no wider change in flooding, align with other flood risk management schemes, and explore opportunities to minimise flooding to others.

We are also carefully considering how we manage water and flooding in how we design the reservoir. We are committed to ensuring the reservoir results in no change to river flooding both now and in the future, while exploring opportunities to minimise flooding to others and provide wider environmental benefits.

For more information, please read our approach to flood management fact sheet below.

We are designing the reservoir in line with the latest national and international industry guidance and standards, and the legislation set out in the Reservoirs Act 1975. This sets the requirements for good design, construction, surveillance and monitoring to ensure the integrity of the embankments.

A requirement is to be able to lower (in a controlled way) the reservoir's water level quickly in the event of an emergency (drawdown). We are in the early stages of developing the plan for how the reservoir will draw down in the event of an emergency.

Our current work shows releasing water from the reservoir in a controlled manner into the Forty Foot Drain and the wider Middle Level system, then on to the sea, as the preferred option. This would avoid water being released into the Ouse Washes or Nene Washes. We are continuing to assess options and will consider the potential environmental effects of an emergency drawdown event as part of the Environmental Impact Assessment.

We will also incorporate several other safety features into the design of our reservoir, to ensure we can continuously monitor the reservoir’s integrity and ensure our plans remain highly effective throughout the reservoir’s operation.

You can find out more about how we’ve put safety at the heart of our emerging design by reading our main site design brochure below.

Over the coming months, as well as seeking consultation feedback, we will be commencing technical and environmental studies to inform the transport options and the projects development and provide more information on likely impacts associated with traffic and transport on the local community and environment.

For further information please see our traffic and transport factsheet below.

The East of England is the driest region nationally, which is made worse by climate change. The Regional Water Resources Plan, and Anglian Water and Cambridge Water's Water Resources Management Plans, consider various climate change scenarios, and have concluded that a reservoir in this location is the best value solution for the region.

When completing our site selection process for the reservoir itself, we had already identified possible water sources that would have water available to fill the reservoir, aligned with our Water Resources Management Plans.

We have identified the following sources as having water available to fill the reservoir, and know that we need to use at least three of these sources:

  • The Middle Level system
  • Either the River Great Ouse or the Ouse Washes (River Delph)
  • The River Nene and its Counter Drain

Our preferred combination of sources won’t be confirmed until after we’ve carried out further assessment and engagement with statutory bodies. Water will only be drawn from the sources when there is enough available, and the water would otherwise drain to the sea.

Both companies’ Water Resources Management Plans identify where the treated drinking water should be sent to, for supplying to homes and businesses via our existing networks of pipes. The treated water will be transferred to each location via a new underground pipeline.

For more information on how the water would reach our customers’ taps, read our associated water infrastructure proposals below.

We started by looking across the broad area between the water sources, the reservoir and the connection points to identify a list of locations and options for the infrastructure we might need.

This included route options for transferring water to the reservoir via new underground pipelines or existing waterways, and possible locations near the water sources for building the equipment needed. It also included location options for a new water treatment works, as well as routes for transferring treated water into supply via new underground pipelines and service reservoirs.

We then looked at this long list of options and assessed them to see which ones were most suitable for what we needed to build, considering the relevant planning policy among other factors such as existing infrastructure and environmental designations.

The most suitable options were then assessed in more detail against a range of criteria including what construction of the infrastructure would involve, natural and historic environment features, and relevant planning designations.

The preferred options we’ve identified are the ones that, when combined, performed best against our appraisal process, achieving what we need to transfer water to the reservoir, treat the water, and supply it to homes and businesses.

Find out more about how we chose our preferred locations by reading our associated water infrastructure proposals.

We are still in the process of assessing whether or not we will draw water from either the Ouse Washes (River Delph) or the River Great Ouse. In the meantime, we've included the identified options for transferring water from both of these sources in our phase two proposals.

While technical discussions and assessments will help us determine the preferred options to proceed with, your insights could also help inform our proposals further. We are keen to hear your views on the areas identified for all options.

We are committed to making sure the project is designed to cause no wider change in flooding, and are also exploring how our proposals might align with other flood risk management schemes.

The reservoir will not be directly connected to any rivers, and would instead draw water from a range of sources through a combination of pipes and existing water courses. Pumping stations would move water from sources and into the reservoir – this is something we are able to control.

When in operation, we can choose when to transfer water from sources, to:

  • only take water from sources when their levels are high, which can also reduce the risk of these sources flooding;
  • not transfer water into a river or channel that is in flood or predicted to be in flood during the transfer period.

Working with the relevant local authorities and stakeholders as our project progresses, we will also consider if improvements to some of the existing channels feeding the reservoir, such as making them deeper or raising their banks, would be needed. This could increase their capacity and reduce their current risk of flooding, as well as potentially helping them respond to increased river and surface flood risk due to climate change.

For more information, please read our approach to flood management fact sheet below.

Where we are not using existing waterways, the underground pipes that transfer water from sources to the reservoir, and into supply, will be between 1-2 metres in diameter. Generally, we’ll need to dig trenches to install the pipelines, and which will then be filled in and the area reinstated.

Where the pipeline routes need to cross a major road, railway route, river or major utility infrastructure, we would look to use equipment to install the pipeline underneath them, that doesn’t involve digging trenches.

At this stage of our work, we’ve identified broad corridors within which the required pipelines would be located. The corridors we’ve identified at this stage are around 500 metres wide – this is much wider than the area we’d need for constructing the pipeline along the route, which we expect to be around 50 metres wide.

The specific pipeline routes haven’t yet been determined. This will be part of our next stage of work, following further assessments and consideration of the feedback we receive.

Your local knowledge is very valuable to us and we welcome any feedback you have on our proposals.

For our phase two consultation, we are asking for feedback on our emerging design for the reservoir, including opportunities for the features it could include. We also want to hear your views on the preferred options and locations we’ve identified for the associated water infrastructure needed to transfer water from sources to the reservoir, treat the water, and supply it to homes and businesses.

We’re also keen to hear your views on our early-stage proposals for areas of land in the vicinity of the reservoir we could need for environmental mitigation and enhancement, construction, or wider uses.

You can submit feedback to us in several different ways:

Please make sure you submit your feedback to us by 23:59 on 9 August 2024.

Yes, the feedback we receive from local people and all our stakeholders is key to making sure we develop our proposals in a way that helps to keep impacts as low as possible and create benefits for people and nature.

All the feedback from our phase one consultation has been reviewed, recorded and has carefully been considered alongside our technical studies, to help inform our latest proposals which we’re now seeking your views on.

A summary of the feedback we received to our phase one consultation can be found below.

If you’re unable to provide written feedback through email, our online form or in writing, or require assistance in doing so, please contact the project team by calling 0800 915 2492 and our team will do our best to assist you in taking part in the consultation.

We were pleased to share our early proposals for the reservoir with communities and stakeholders in our first phase of consultation in autumn 2022, and we are grateful to everyone that provided feedback.

It was great to talk to local people and other stakeholders to understand their thoughts and comments. It is clear they see great value in the environmental and recreational benefits the reservoir could bring and are excited by what it could mean for the region.

At the same time, people shared their concerns about a wide range of topics and potential effects on local communities and roads in the area. The local community also want to know what this will mean for the people whose homes, land or business may be affected by our plans.

We published a summary of the feedback we received during our first phase of consultation, which is available below. The feedback has been used to inform the development of the project, which we are now presenting in our second phase of consultation running from 30 May to 9 August.

Yes, our current consultation, which is open from 30 May to 9 August, will be our second in a multi-phase approach. There will be at least one more consultation on our proposals, including a statutory consultation required by the consenting process we must follow for the reservoir.

We are hosting a programme of in-person community events both near the main reservoir site and areas which will be affected by the associated water infrastructure proposals we’ve identified at this stage. We also will be hosting two community webinars.

For more information on these events or to register to attend a webinar, please register here.

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Contact the project team today.

Freephone: 0800 915 2492


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