Yorkshire Water has warned it will be left facing prosecution unless custodians of one of the country’s most highly-protected landscapes allow the introduction of safety-related changes to a reservoir once judged to be the highest dam in the country.

The utility firm has applied for consent to introduce steel, plastic and concrete structures to the Upper Barden Reservoir, on the Duke of Devonshire’s moorland above some of the most visited areas of the national park, in Wharfedale.

As well as being in the highly-protected national park, the reservoir is bordered by the designated North Pennine Moors special conservation and protection areas as well as the West Nidderdale, Barden and Blubberhouses Moors Site of Special Scientific Interest.

The 2.1 million cubic litre reservoir, which was authorised by Act of Parliament in 1875 partly to supply soft water for the processing of woollen textiles in Bradford 30km to the south-east, still provides water to the city via the Nidd Aquaduct.

The 480m-long and 38m-high earth embankment dam was designed by Alexander Binnie, a civil engineer responsible for the first Blackwall Tunnel under the River Thames.

The planning application to the Yorkshire Dales National Park Authority states the proposed development would introduce a steel siphon pipe supported on steel cradles, a concrete headwall exiting into a natural rocky channel, a steel gantry and a glass reinforced plastic kiosk.

The document states the changes have been designed to have the least impact possible on the landscape, in line with national planning policy which places great weight on conserving and enhancing landscape and scenic beauty in national parks.

It states the proposed development would have no residual impact on the designated conservation sites with a series of proposed mitigation measures.

A heritage study submitted by Yorkshire Water with the application concludes the changes would have “a negligible impact” on the historic landscape.

It adds: “The new features can be seen as appropriate and sympathetic modern interventions that facilitate the continued use of the asset for the purpose of its construction.”

The planning documents state the works are needed to increase the drawdown capacity of the reservoir, to increase the rate at which water levels within the reservoir can be lowered in the event of an emergency, in line with the recommendations of a safety inspection.

They state: “As such, it is critical that this planning application is approved to ensure that Yorkshire Water can meet its legal obligations with respect to The Reservoirs Act.”

The papers say Yorkshire Water would be in breach of the legislation if the works are not completed before March 31 next year, leading the Environment Agency to service notice and pursue a prosecution.

The papers state: “It is therefore imperative that the proposed development is completed at the earliest opportunity.” 

The application adds while there would be “some adverse visual changes to sensitive receptors”, predominately within the national park, the perception of change will be “limited generally by the siting of the proposed development, existing screening, and distance from the site”.

It concludes: “It is unlikely that the new equipment associated with the proposed development, such as the gantry and pipework, will appear out-of-context, given the nature of the existing, surrounding reservoir infrastructure.”