The Saturday essay: A return of the Roman Broads?

The Hickling Broad Estate is on the property market with a guide price of £2.3m

A boat heads out onto Hickling Broad, a gentle landscape that could be transformed by rising sea levels - Credit: Archant

Climate change and sea level rises are predicted to turn the Broads back 2,000 years. Jasper Copping reports on what that might mean, and whether it can be stopped

By the mid-1970s, the last cargo of timber had been delivered to the port of Norwich.

Little over 10 years later, the final ship called at Read’s flour mill, which then stood by Carrow Bridge.

In 1990, the port itself was closed down and centuries of the Broads as a route for trade ended.

The trading wherries - the most famous symbol of that era - had vanished decades earlier, as the waterways gradually became the recreational playground and wildlife sanctuary we know them as today.

The Broads, then, have undergone fundamental change before. And they will do so again.

It seems certain that climate change will play the leading role in deciding what happens next.

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Indeed, it doesn’t seem too melodramatic to suggest that it may have a more dramatic and direct effect on this landscape than any other in Britain.

The Broads’ low-lying nature and proximity to the North Sea mean the area is particularly vulnerable to sea level rises.

Some experts predict an increase of between half a metre (19in) and a metre (39in) in the sea level over the next 100 years. A one-metre rise would put much of the Broads underwater. There will be no escaping those consequences.

Ask those who live and work near the Broads or who visit them regularly and they will tell you that they are already seeing the consequences.

High water levels and flooding are an increasing problem for riverside businesses and homeowners, particularly during these winter months.

And high water also means that fewer boats can now pass beneath the low medieval bridges at Potter Heigham, Wroxham and Beccles than in the past.

So what, if anything, is the answer? This week, the Broads Society came up with some suggested solutions.

Some were very traditional, such as a greater use of drainage dykes to manage water levels. Improved dredging of the rivers has also been proposed.

But one particular idea from the Broads Society was more modern, more eye-catching and more radical: a flood barrier at Great Yarmouth to manage - or block - the flow of water during extreme high tides.

In truth, this is an idea that has been floated - if you forgive the phrase - before, but has never got any further than the drawing board.

Perhaps the situation did not seem so acute when the idea was previously suggested. Perhaps, the political will and cash needed to make it happen was not apparent. Or perhaps the solution is simply not a practical one.

A flood barrier would certainly do nothing to protect the Broads’ northern flank, where areas like Horsey Mere and Hickling Broad remain vulnerable to the threat that the sea could one day breach the coast north of Winterton.

TRANSPORTRIVER SCENE1At Norwich port two barges are offloading cargoes in the early 1950s. The Opal

Timber is unloaded in the port of Norwich in the 1950s

And what about Yarmouth itself? The town sits on a shingle sandbar squeezed between the Broads and the sea. Any attempt to stop the flow of water around it could have unforeseen consequences.

And would a flood barrier actually do the job it is required to do? Part of the problem facing the Broads is not just the threat of seawater coming in up the rivers from the sea, but the issue of getting enough freshwater out of the rivers and down to the sea - to keep the levels low and prevent flooding.

During emergency periods, a barrier might stop water from heading inland during extremely high tides at the coast. But what if those emergencies coincide with periods of flooding and heavy rainfall inland? Where does that water go, if a barrier is blocking its route to the sea?

There may well be engineering solutions that can answer these questions satisfactorily. Certainly, the Broads Society is doing an important job in raising this issue and forcing it up the agenda.

The Environment Agency do not rule out a flood barrier and say it is under consideration, so it is unlikely we have heard the last of this particular idea.

But if that approach is not going to work, then what will? Because the sea rises are inexorable. Something is going to have to be done to protect the Broads from them.

Or perhaps it isn’t.

The attitude of the Broads Authority seems to be more fatalistic.

In a recent interview, its chief executive John Packman acknowledged that climate change and sea level rises were going to transform the waterways, and that this was something we would have to accept.

He suggested that in 100 years time the Broads will be more like they were during the Roman period than they are now. "If you look at the maps of when the Romans were here, it was a very different landscape," he said. "We may see something that may be more familiar to the Romans than it is to us."

Chief executive of the Broads Authority, John Packman. Photo: Denise Bradley

C - Credit: ©Archant Photographic 2009

If that is what does transpire, then it will be a truly different landscape, unrecognisable from today.

The exact nature of the Broads of the Roman  period are hard to ascertain. For a start, the Broads themselves did not exist, as the peat diggings which formed the spaces of open water did not come until centuries later.

But we do know that the east of the county was dominated by a vast estuary, named Gariensis, which went as far inland as Acle, and entered the sea where Yarmouth now stands.

The Roman settlements at Caister and Burgh Castle guarded its northern and southern shores respectively.

The area to the north was effectively an island, the Isle of Flegg, covering a vast swathe of coastal Norfolk, from Caister up to Winterton, and stretching inland until it sloped away to a boggy area where the River Bure now flows south.

To the north of the island was another estuary, smaller and shallower than at Gariensis, where what is now the River Thurne entered the North Sea.

In the centuries since then, this estuary has been reclaimed by the land and the Thurne has reversed direction, flowing south west into the Bure.

Where the estuary once stood is a low-lying and exposed stretch of coast which remains vulnerable to the sea, as we have seen in recent days, with further erosion at Winterton.

But it is also an area now home to many villages, whose residents we can be sure would not appreciate a return of this particular feature of the Roman Broads.

In general, the Roman Broads would have been boggier, wilder, saltier, more tidal and harsher than now.

The modern Broads reflect a gentle equilibrium of the land and the water, which has created a fragile landscape.

In the Roman times, it was water that was in the ascendancy. Without action, it will be again. It is a prospect that will alarm many, and should concentrate the minds of those who want to avoid it.

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