You are here : Sundon Proposal

Our Proposal

Why we need it

The need for the new water conditioning facility comes from Affinity Water’s commitment to significantly reducing borehole water abstraction from chalk streams in the Chilterns, which is set out in our ‘Revitalising Chalk Rivers Programme.

As we reduce the amount of water we abstract from these chalk streams, we must continue to meet demand for water within our supply area. This means we need to increase the supply of water from alternative sources.

The new conditioning facility would enable Affinity Water to bring water though an existing pipe network to deliver water into our catchment supply area in St Albans, Welwyn Garden City and around Luton. The water will come from Anglian Water’s Grafham Water, England’s third largest reservoir, near Huntingdon, which is around 40 miles away.

While there is no requirement for any new underground pipes to move the water to or from the facility, there is a need to adjust the chemistry of the water through a process called ‘conditioning’. This will lower the risk for any potential discolouration.

This site has been part of Anglian Water’s network for many years. That means it already has the underground reservoir that we need to manage the water conditioning works, along with underground water pipes to move the water in and out of the site. The works we need to undertake are minimal in comparison with the development and construction of an entirely new facility elsewhere.

This is the best solution available to help reduce borehole water extraction in the Chilterns. The volume required would not be practical to transport in water tankers, which would also create significant impact on the environment from CO2 emissions.

Map of area the reservoir will cover

This water conditioning plant will enable us to continue our commitment to significantly reducing borehole water abstraction from key areas and restoring chalk streams. This includes the River Chess in the Chilterns Area of Outstanding Natural Beauty, along with ground water extraction in the Ver, Mimram, Upper Lea and Misbourne catchments by 2024 to leave more water in this natural environment.

Details of Affinity Water’s supply area can be found here.

  • Design and operations

    Our proposals include:

    • Two water treatment/conditioning buildings.
    • Control building.
    • Two carbon dioxide storage silos.
    • Improvement to the junction with Streatley Road.
    • New hedge planting and screening.
    • A characteristic and attractive feature of the Chilterns landscape.
    • A globally rare habitat confined to north west Europe and to the UK in particular. More than 85% of all the chalk streams in the world, are found in England.
    • Important habitats for wildlife and support a massive range of plants and animals.
    • Home to some of our most threatened plants and animals, such as the water vole and brown trout.

    The existing facility lies in the green belt, making it particularly important that our proposal is sensitive to the local environment and surrounding countryside.

    We are committed to ensuring our proposal takes particular care to minimise and where necessary, mitigate any impact on the local environment and the surrounding countryside. In turn this will allow us to deliver clear environmental benefits by reducing borehole water extraction from chalk stream beds in the Chilterns.

    Proposed plan of the site

    Site layout plan

    The facility will fit within the agricultural landscape and will be designed to look like farm buildings.

    The buildings will be designed to integrate into the predominately agricultural landscape. The building will be screened from Streatley to the east by the existing reservoir structure, and from Upper Sundon to the west by additional tree planting.

    What the site will look like from the North

    Elevation - View from North.

    What the site will look like from the East

    Elevation - View from East.

    What the site will look like from the South

    Elevation - View from South.

    What the site will look like from the West

    Elevation - View from West.

    The facility will not generate any operational noise that can be heard from nearby villages. It will be manned periodically during normal working hours. We will need to deliver chemicals required for the water conditioning in tankers and anticipate there will be one or two deliveries a day during the week, with no deliveries at the weekends.

    We are committed to ensuring our proposal takes particular care to minimise and where necessary, mitigate any impact on the local environment and the surrounding countryside. In turn this will allow us to deliver clear environmental benefits by reducing borehole water extraction from chalk aquifers that feed chalk stream beds in the Chilterns.

It is our intention to create a net gain in biodiversity. That means we will create more natural habitats than we need to remove.

We propose to introduce additional planting along the site boundaries as well as, where possible, provision of wildflower mix as part of the restoration, making best use of the land available.

  • Chalk stream conservation

    "Unsustainable abstraction still diminishes some of the most iconic catchments and important habitats in the country, such as chalk streams, which are a globally important habitat. There are more than 224 chalk streams in the UK. These represent 75 to 80% of this habitat type globally and must be protected. Sustainably abstracted water bodies are more resilient to climate change and drought so addressing unsustainable abstraction will help improve resilience."

    Environment Agency - Meeting our future water needs: a national framework for water resources (March 2020)

    Wildlife images: a bird, a flower and a butterfly

    The majority of the world’s chalk streams are found in England and their global rarity means they should be viewed in the same light as an English Great Barrier Reef or rainforest.

    Truly special habitats, chalk streams are home to an abundance of wildlife species such as water crowfoot, flag iris, mayfly, brown trout, kingfisher, otters and the nationally endangered water vole.

    Chalk streams are at risk of extinction as the impacts of climate change combine with increasing demand for water from a growing population. Today many English chalk streams are dry in long stretches and do not meet the objectives set out in environmental legislation.

    Affinity Water is committing to ending environmentally unsustainable abstraction from these precious river catchments and to work in collaboration with other water companies, industries, universities and NGOs to develop alternative, sustainable water supplies away from chalk river catchments.

    According to the Chilterns Area of Outstanding Natural Beauty (AONB), chalk streams are:

    • A characteristic and attractive feature of the Chilterns landscape.
    • A globally rare habitat confined to north west Europe and to the UK in particular. More than 85% of all the chalk streams in the world, are found in England.
    • Important habitats for wildlife and support a massive range of plants and animals.
    • Home to some of our most threatened plants and animals, such as the water vole and brown trout.

    This project will allow Affinity Water to reduce bore-hole water abstraction from chalk aquifers that feed chalk streams and support its commitment to chalk stream restoration in the Chilterns.

    More information on chalk stream conservation can be found at:

Key documents and downloads