Victorian aqueducts get a makeover

Yorkshire residents might be surprised to learn that a vast network of 62,000 miles of water and sewerage mains, enough pipework to circulate the earth, runs beneath the county.

The supply network for Bradford and surrounding area includes tunnels, aqueducts, culverts and pipes that transport water from reservoirs to water treatment works and then to our customers. Bradford residents might be shocked to learn how far away the source of their drinking water is located.

In 2014 we embarked on a three year programme of improvements to the Nidd and Barden aqueducts which transfer water from reservoirs in Nidderdale and Upper Wharfedale to Chellow Heights water treatment works (WTW) in Bradford and Graincliffe WTW in Eldwick.

These aqueducts date back to Victorian times, Barden is nearly 160 years old, and were commissioned to supply the rapidly expanding city of Bradford during the Industrial Revolution for drinking water and wool processing.

Detailed surveys by a team of specialist engineers generally showed the structures to be in remarkably good condition but in places they needed a little TLC to help provide a reliable future service.

Engineers from OVIC, Ken Rodney Construction and Mott MacDonald Bentley have been involved in this project which has seen £3.6million invested in these assets.

The project has involved minor structural remedial works, such as resetting of keystones and re-grouting, to major structural works, like the installation of internal structural bracing and the full replacement of some sections. The work has been carefully coordinated to minimise the impact on the water supply to Chellow Heights and Graincliffe to ensure customers do not go without water.

The Nidd aqueduct took four years to construct (1894 -1902) and transfers 130 million litres of raw water every day from Angram and Scar House Reservoirs in Upper Nidderdale along 40km of tunnels, aqueducts and bridges to Chellow Heights WTW. The aqueduct is lined with concrete and inside it measures over 6ft high. To cross the Wharfe and Aire valleys, cast iron and steel pipelines were laid underground.

Chellow Heights was constructed in the 1960’s in north west Bradford, and provides quality drinking water to all homes in Bradford along with surrounding towns and villages including parts of Mirfield, Morley and Brighouse. The works can also supply water by our grid network to Leeds and Halifax when necessary. Chellow Heights has other raw water sources including the river Wharfe via Chelker pumping station and Thornton Moor and Stubden reservoirs.

Completed around 1860 Barden transfers around 30 million litres of raw water per day from Lower Barden reservoir together with water collected from the moors near Burnsall to Graincliffe WTW. The water passes through 22kms of tunnels and 42 inch diameter aqueducts, constructed from Yorkshire sandstone blocks, before it gets to Eldwick.

Graincliffe was built in the mid-1990’s and supplies drinking water to Bingley, Baildon, Riddlesden, Otley, Heaton, Ilkley and also supports Keighley.

Next month Mott MacDonald Bentley will start working on a section of the Nidd aqueduct near to Skyreholme. Most the structural work in the Barden tunnel was completed last year but Ken Rodney and OVIC will return to Nidderdale in April to carry on with the programme of minor repairs. If you are visiting these beautiful parts of Yorkshire you might well be walking above engineers working in the tunnels beneath your feet without ever knowing!

Mark Broady Yorkshire Water Project Manager said, “The aqueducts are fantastic feats of Victorian engineering but they are both well over a hundred years old and needed some repairs. Our partners have been hard at work since 2014 and the project should be complete by the end of 2017.”

“The Nidd and Barden aqueducts together transport 160 million litres of water to Chellow and Graincliffe works every day which is enough to supply nearly 300,000 properties. This project will ensure the security of water supplies to Bradford and surrounding area for years to come.”