AN EXPERT at the Friends of Bradford’s Beck has written about his research into lost urban rivers and how “daylighting” these watercourses now could transform cities, including Bradford.

The group's chairman, David Lerner, is a professor of environmental engineering at The University of Sheffield, and has been carrying out research into the impact of returning a culverted river to open water.

He has written about his research for a website dedicated to views from the academic and research community.

Prof Lerner, also known as Barney, discusses how very few rivers are visible in most city centres.

"In my home city of Bradford there is virtually no trace of the small main river, the Bradford Beck, or most of its urban tributaries. In Bradford alone, more than 25km of streams have been covered over and now flow within an engineered structure known as a culvert.

"Rivers were put in culverts partly to contain the smell. Bradford grew from a town of 15,000 in 1800 to 100,000 by 1860 as it became the richest city in England on the back of the wool trade, yet the first mile of public sewer was not laid until 1862 and first sewage works not completed until a decade later.

"Until then much of the sewage and industrial waste ended up in the Beck or canal which must have smelt appalling – it is said the canal was so putrid that it could be set on fire.

"Rivers were also put in culverts to make flat land available. Buildings were constructed over the river itself, combined with raising the boggy land of the flood plain with ashes and other wastes. In Bradford at least, most of the culverts are under buildings rather than roads or public spaces. They often have a wall down the centre of the river, indicating that the two owners built out to the edge of their property."

He describes how "daylighting" is the action of returning a culverted river to open water. At its simplest, this could be taking the lid off the culvert, h adds.

"It makes sense to do this now that the benefits of Victorian-era culverting have given way to modern problems of old age, pollution, capacity and blockage, and the loss of the pleasure of water. No engineering structure will last for ever – culverts have to be maintained and eventually replaced if the buildings and infrastructure above are to be safe," he adds.

Prof Lerner and colleagues have been researching the impact of "deculverting" for over a decade and in the 96 urban projects the review has looked at, daylighting was mostly driven by "a desire to create new habitats, to reduce flood risk, provide new amenities and as part of regeneration projects".

"Water gives a sense of place in a city, and often becomes a focus for civic activities. Wildlife will return to the city – even if it is just ducks," he adds.

Prof Lerner also describes how successful daylighting projects have mostly been suburban or parkland sites. Major urban daylighting projects are rarer, he reveals, such as the opening of the Roch in the centre of Rochdale to reveal the river and a 14th-century bridge.

He concludes that earlier generations culverted their rivers for reasons which were good at the time. But times have changed and that daylighting offers the opportunity to reduce flood risk and bring water and nature back to towns and cities.