Posted by: lensweb | July 15, 2016

LENS Meets an Iron Giant

 

Mon July 11,  Bennerley Viaduct and Nottingham Canal

Meet 7pm Follow Shilo Way from Ilkeston and park at small car park left off Newton’s Lane.Grid ref  SK 476 433   Postcode (nearby)  NG16 2SE

Leader: Marion Bryce

Who would have thought it would be such a fine evening at Bennerley?

It was single file along an immaculate towpath fringed by flowering water loving plants Galingale is an unusual decorative sedge with reed sweetgrass, water figwort, great hairy willowherb, hemp agrimony, yellow flag, branched bur-reed and meadow sweet. Reed and soldier beetles, banded demoiselle, blue tailed and common blue damsel flies ornamented the lanceolate leaves. The strange flowers of yellow water lilies with brandy bottle fruits haphazard among  huge flat floating leaves.  The reason why the flowers smell of alcohol is the anoxic conditions  in which it is growing: without oxygen the sugars in the roots cannot be converted to energy and carbon dioxide via the normal metabolic process for plants, and have to proceed via an alternative synthesis (like yeast) where it is converted to alcohol. But, as you know, alcohol is poisonous to most species, and must be disposed of….In Yellow Water Lily it is evaporated out of the yellow flowers. In the still air of the evening we get the full effect.

Nottingham Canal, opened in 1796, was a 14.7-mile (23.7 km) long canal between Langley Mill  and Nottingham used to break the Erewash Canal company monopoly on carrying coal. It left the River Trent to serve a number of wharves in Nottingham, and then rose through a further 18 locks, most of which were grouped together at the Wollaton flight, to reach a long upper pound. At its upper end, a stop lock connected it to the Great Northern Basin, which provided access to the Erewash Canal  and the Cromford Canal. It was successful but competition from the railways began in the early 1840s and led to it falling into disuse.

Nottingham City Council bought the section from Lenton to the city limits and began filling it in from 1955. 6 miles (9.7 km) of the upper section was bought by Broxtowe Borough Council  to retain as a Local Nature Reserve. There was a brief attempt at re-opening the upper section for navigation, but the construction of the Awsworth Bypass in 1980 severed the canal, and the plan became unworkable.

The trees clear to reveal the monumental wrought iron lattice work structure of Bennerley Viaduct, 1452 feet long, 60 feet high which was designed and built by Richard Johnson (Chief Civil Engineer of the GNR);  contrary to local rumour, Gustav Eiffel was not involved. It carried the Great Northern Railway over the River Erewash, Erewash Canal (bottom cut), Nottingham Canal (top cut), Bennerley Marsh and the Midland Railway. Most railway viaducts at the time were brick built but the foundations of the Bennerley Viaduct were subject to a great deal of coal mining subsidence therefore, the lighter, more flexible, wrought iron design with was chosen. It was a showcase for local industry, ironworks and brickworks. The viaduct consists of 16 lattice work   deckspans , each 76 feet long supported on hollow wrought iron columns with stone capped blue brick foundations. Whereas masonry arches work on compression, wrought iron gives a more flexible structure which wobbles under dynamic loading. Engineers recall holding tight onto the inspection panels under the bridge when a steam train passed over and the sound, mat snap daddy. Stronger than modern steel and corrosion resistant. no two iron bridges are alike as iron was a new building material and a close look at the joints shows the use of old methods more suited to carpentry.

 

The cast iron footings stand on a foundation look of blue bricks, stamped Derby, on top of timber (anaerobic conditions stop rotting). Not trusting the new-fangled methods, the Midland Railway Company insisted on brick piers over their railway lines.  Construction was rapid, the viaduct was built between May 1876 and November 1877 and opened in January 1878.

The viaduct was built for the railway line between Awsworth Junction  and Derby  and formed part of the Great Northern Railway Derbyshire Extension which was built to exploit the coalfields. Bennerley Ironworks was originally due north of the viaduct served by sidings connected to both the Great Northern line and the Midland Railway Erewash Valley line. After the demolition of the ironworks a British Coal  distribution depot served by sidings from the former Midland Railway occupied the same site.  This has now also been demolished  to give an extensive brownfield site which is covered with wild flowers. Clover, mignonette, yellow and white melilot, great mullein, tufted vetch and bird’s foot trefoil support large populations of butterflies and other insects. Unusually for us, large skippers, small tortoiseshell, green veined white and ringlets were flying into the evening. We could smell the coal from steaming black puddles.

In 1980 when British Rail proposed to demolish this structure it was opposed by the Bennerley Viaduct Preservation Trust who argued it’s value as a rare and impressive example of Victorian railway architecture and treasured Erewash Valley landmark. On appeal Michael Heseltine, then Secretary of State asked, ‘Can we find a use for it?’. The viaduct was purchased for £1 and is now the focus of a major Sustrans project to bring it into use again as a cycling and walking route. It will be the iconic centrepiece of the Great Northern Greenway: a traffic-free route between Nottingham and Derby connected with the local network of paths including the Erewash Valley Trail. When Sustrans needed expert advice the Society of Mechanical Engineers recommended David Gent and as coincidence would have it he lives just down the road and now is a Friend of Bennerley Marsh, volunteers who have regular work parties. Plans have been made which not only celebrate our Industrial Heritage but also wildlife. They include pathways beneath and on top of the structure, a bird hide and environmental classroom. Inspection of the underbelly reveals that cleaning and painting the structure would be difficult as there is so much wildlife. Bats, barn owls, kestrels, great tits and jackdaws have made home between parting pier panels and the rusting mild steel balustrade which was a later addition.

Looking out over the marshy fields on the other side, skylarks and lapwings nest, herons and white egrets probe pools of standing water. Imperial purple drooping racemes of Russian comfrey are large plants leaning by the River Erewash. A disease resistant elm has been planted to encourage white hairstreak butterflies.

The settling ponds beneath the viaduct are home to grass snakes and great crested newts. The surface is covered by the flat green leaves of broad leaved pondweed, colourless flower spikes protruding above the surface. China mark moths, ringed and brown, common blue and azure damselflies and hundreds of emerald damselflies fly up as we disturb the long grass behind the ponds. Southern marsh orchids and common spotted orchids and their many hybrids push pink spikes above mouse ear hawkweed, pink centaury, purple self-heal and yet more ‘egg and bacon’ in a celebration of wildflowers.

As we look back to the ‘Iron Giant’ connecting Nottinghamshire to Derbyshire where the diocese of Canterbury meets the diocese of York, imagine flowing purple robes, scarves flapping, mitres fully erect as the Archbishop of Canterbury cycles to greet the Archbishop of York over the newly opened Bennerley Viaduct. Is it a dream or reality?

Heritage Lottery Funded ’Rediscovering Bennerley Viaduct’ project are holding an exhibition at Erewash Museum in Ilkeston. Which runs until 30 August.

Marion Bryce 15 July 2016


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