Old canal network in front line against flooding

SCOTLAND'S network of Victorian canals is to be deployed to help prevent serious flooding in homes and businesses across the country.

• The sea lock of the Crinan Canal, which once formed a vital link in Scotland's transport system. Below: Steve Dunlop, director of British Waterways Scotland, says facilities could prove vital. Photograph: British Waterways

Millions of litres of water could be quickly diverted away from danger areas following downpours, under plans drawn up by British Waterways Scotland (BWS) to protect low-lying areas in Glasgow, Edinburgh and other parts of the Central Belt.

BWS, which operates the country's canal system said canal levels could be lowered in advance of deluges by draining water through existing outlets along their routes. Any influx of extra water could then be similarly discharged safely into rivers away from flood risk areas.

Canals such as the Forth and Clyde and the Union could also be deepened by up to three feet in places by dredging to enable them to take even more water. Rainwater from downpours would be fed into lowered canals via inter-connected rivers and drains. Alternatively, pumps or new drainage routes could be installed in high-risk areas to move more water into canals.

BWS said using canals would have eased the serious flooding which hit south and central Glasgow in 2002, in which a month's rainfall fell in an afternoon.

The torrent engulfed more than 200 homes and railway stations and tunnels, causing major disruption to trains and millions of pounds of damage.

Hundreds of homes in Edinburgh were also affected by major floods in 2000 and 2002 when the Braid Burn and Water of Leith burst their banks.

Although the scale of the flooding witnessed in Australia last week is unlikely, experts warn that the danger to urban areas in Scotland is mounting from climate change. Rainfall is expected to increase in line with global trends and flash floods from torrential downpours are expected to become more common.

The Scottish Environment Protection Agency (Sepa) has warned of potential flooding this week as a widespread thaw of snow in hill regions leads to rising river levels.

BWS director Steve Dunlop said the canal network could make a significant contribution to flood mitigation. "When high rainfall is forecast, we could lower the levels of a canal to enable it to accept more water, so it could be used as a sink. People think canals are stagnant bodies, but they can move water fairly rapidly away from areas in danger."It would give canals a new economic and social role for all those who thought they were assets from the past or just for a few boaters."

He added that the plan "would not cost an awful lot of money", although dredging - to increase a canal's capacity to hold water by up to 15 per cent - is a more expensive option.

BWS believes its proposals could have the greatest impact in Glasgow because the city's drainage system is already under severe pressure. The Forth & Clyde Canal flows across the north of the city, with a branch to Speirs Wharf, just north of the city centre. Running between Grangemouth on the Forth and Bowling on the Clyde in West Dunbartonshire, it contains 1,435 million litres of water, the equivalent of nearly 18 million domestic baths.

Elsewhere, BWS said there was also potential for using the Union canal, which terminates at Fountainbridge in central Edinburgh, and the Caledonian canal in Inverness, to address flood risks in those cities.

The plans are expected to be implemented by the Metropolitan Glasgow Strategic Drainage Partnership, which was established after the 2002 floods. BWS would become a member of the group, which comprises Glasgow City Council, Scottish Water, Sepa and Scottish Enterprise.

A Scottish Government consultation paper launched last month proposes a national water management system, of which BWS said canals should become a vital part.

The Metropolitan Glasgow Strategic Drainage Partnership welcomed the BWS initiative. Steering group chairman Sandy Gillon said: "I'm pretty confident it will happen. Canals are a major piece of infrastructure and British Waterways has a lot to offer in terms of flood management."

Calum MacDonald, the operations director of Sepa, said: "I expect British Waterways would become a valuable partner, bringing with it a wealth of experience in helping protect the water environment and providing new insight into alternative methods for managing flood risk."

However, Mike Donaghy, an environmental consultant who has worked on flooding for environmental group WWF Scotland, sounded a note of caution about the plan: "It's a good idea, but let's see how much of a contribution it can make."