Special Report: ‘Flood storage’ proposals to prevent future devastation

Graham Appleby, Chairman of Rivelin Valley Conservation Group at the site of a proposed flood storage area in the Rivelin Valley which he says poses a threat to wildlife and allotments
Graham Appleby, Chairman of Rivelin Valley Conservation Group at the site of a proposed flood storage area in the Rivelin Valley which he says poses a threat to wildlife and allotments
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£19m plan to safeguard businesses along Don Valley nearing completion but remaining work to keep city residents secure including flood alleviation scheme for Sheffield rivers will cost an extra £64m.

A decade after the 2007 flood left much of Sheffield submerged, killing two people, leaving hundreds homeless and destroying many livelihoods, work is continuing to protect the city against a similar catastrophe.

Graham Appleby, Chairman of Rivelin Valley Conservation Group at the site of a proposed flood storage area in the Rivelin Valley which he says poses a threat to wildlife and allotments

Graham Appleby, Chairman of Rivelin Valley Conservation Group at the site of a proposed flood storage area in the Rivelin Valley which he says poses a threat to wildlife and allotments

A £19m scheme to safeguard businesses along the Lower Don Valley, including the construction of a huge new wall, is nearing completion.

But there is much more to be done elsewhere in the city, with the council anticipating the remaining work will cost an additional £64m.By far the biggest project in the pipeline is the flood alleviation scheme planned along the Upper Don, Porter Brook and Sheaf rivers, for which the estimated price tag is £53m.

Building flood defence walls, planting more trees to absorb the water and installing ‘debris catchers’ to prevent blockages at bridges and other pinch points are among the measures envisaged.

But probably the most controversial part of the wide-ranging proposals being considered is turning parks, sports grounds and other spots into ‘flood storage areas’ which would hold water at times of heavy rainfall to prevent built-up areas being inundated.

It makes more sense to use a managed area like the park

More than 1,000 people had their say on draft plans during a consultation last year, and the initial list of 16 potential flood storage areas has now been whittled down to seven.

Some of the original proposals were ruled out because of the potential harm to woodland, the impact on homes or strong objections from landowners.

The most unpopular option during the consultation was storing floodwater at a spot in the Rivelin Valley known as Wolf Wheel.

Nearly half those who were consulted opposed the plan, with less than a third in favour, and it was dropped amid fears about the impact on wildlife and obstacles to construction.

Graham Appleby, Chairman of Rivelin Valley Conservation Group at the site of a proposed flood storage area in the Rivelin Valley which he says poses a threat to wildlife and allotments

Graham Appleby, Chairman of Rivelin Valley Conservation Group at the site of a proposed flood storage area in the Rivelin Valley which he says poses a threat to wildlife and allotments

But while most people recognise the need to improve Sheffield’s flood defences, the remaining seven proposed flood storage areas are not without their detractors.

The most controversial one still on the table is at Roscoe on the Rivelin Valley, which would hold an estimated 217,199 cubic metres of water – equivalent to 87 Olympic-sized swimming pools – reducing flood levels downstream by more than 1.2 metres.

Plans to build an embankment there close to Rivelin Valley Park were opposed by 49 per cent of those having their say, with just 32 per cent saying the proposal merited further consideration.

The Rivelin Valley Conservation Group is vehemently opposed, arguing that a dam more than 11 metres high and 150 metres wide would destroy precious habitats and the remains of many old watermills which are part of Sheffield’s heritage, as well as submerging allotments during storms.

Land at Elliotville Street and Stony Walk in Walkley that residents are trying to register as a village green to stop developers building on it

Land at Elliotville Street and Stony Walk in Walkley that residents are trying to register as a village green to stop developers building on it

Graham Appleby, who chairs the group, told how members had put together alternative proposals to release water from the Rivelin Dams ahead of storms so they had more capacity when the rain began falling.

“We’ve been told dropping water levels in the dams by one metre before a rainstorm would enable them to hold an equivalent amount of rainwater to the dam the council wants to create by building an embankment near the park,” he said.

“If they build the embankment it would really spoil the valley. We want to do what we can to minimise the impact but obviously we still support reducing the flood risk in Sheffield generally.”

Sheffield and Rotherham Wildlife Trust has praised Sheffield Council’s ‘strategic approach’ to reducing the flood risk across the city, and welcomed its decision to drop some of the more controversial plans for flood storage areas it claimed would have harmed the ecology.

But the charity still has concerns about remaining plans for large embankments to hold back water at wildlife sites in the Rivelin and Loxley valleys. It has called on the council to ‘make space for water in ways that work with nature, rather than against it’.

As well as planting more trees, it says the council could take inspiration from Centenary Riverside in neighbouring Rotherham – an old industrial site transformed into a wetland reserve which soaks up water during heavy rainfall.

Endcliffe and Millhouses parks are among the other sensitive sites which could be used to hold back floodwater.

During consultation a clear majority said the plans for both sites should be taken forward, but friends groups say the details need ironing out.

The Friends of Millhouses Park, where 14-year-old Ryan Parry was swept to his death in 2007, says it supports the proposal for a flood storage area holding up to 21,000m3 of water in principle and is keen to work with the council to develop the plans.

“In our view it makes more sense to use a managed area like the park rather than an area of wild countryside where any scheme is likely to be intrusive,” the group has said.

“That said, the scheme does have its implications and some compensatory work would be needed in the park.”

At Endcliffe Park, a horseshoe-shaped embankment would be built to hold back 40,500m3 of water.

The council says existing facilities would be protected and the park would only hold water for short periods during ‘significant’ storms, with resources in place to quickly mop up afterwards.

Ann le Sage, who chairs the Friends of the Porter Valley, said the group was keen to cooperate with the council to protect the city from flooding but wanted to ensure public access was maintained when detailed plans are drawn up.

The council plans to select its preferred options for flood alleviation measures along the Sheaf and Upper Don in the next few weeks before submitting its business case to the Government for funding.

Should government cash be secured, work will begin next year on detailed designs and further consultation will take place.

Councillor Bryan Lodge, cabinet member for the environment said: “We need to create the right balance between protecting our landscapes and protecting this city from the scale of flooding we suffered 10 years ago.”