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15/05/2019

Glasgow City Deal: Case study - Smart thinking

Words: Simon Wicks
Spiers Wharf on the Forth and Clyde Canal

Location: Forth and Clyde Canal, Glasgow

Project: Smart canal - an automated system of managing water levels in the Forth and Clyde canal to remove flood risk during storms

Cost: £17 million (capital funding from Glasgow City Region City Deal, European Regional Development Fund via the Green Infrastructure Fund and Scotland’s 8th City, the Smart City)

The Sighthill regeneration illustrates a major issue that Glasgow city region faces in unlocking land for development in strategically sound places, and in managing the transition form a post-industrial to a modern knowledge-based economy.

Glasgow’s industrial past and its growth as a city was shaped by its proximity to water – notably the estuary of the River Clyde, but also its tributary, the River Kelvin, that flows into the Clyde just west of Glasgow city.

Shipbuilding is the most obvious of the industries that have shaped the city. But so, too, has its geographic position which makes it ideal as port. To facilitate the city's industries, the Clyde – a relatively shallow, wide, slow-flowing river – was dredged and banked and deepened. It’s a river with just two tributaries at this point – on the north bank the River Kelvin enters the Clyde just west of the city; on the south bank the River Cart flows around the site of Glasgow City Airport a few miles further west (where a hi-tech business park is planned).

The waterways were added to in the late 19th century with the Forth and Clyde Canal, constructed in the late 18th century to enable the movement of goods and raw materials to and from the Clyde estuary, into the Scottish interior and all the way to the nation’s east coast. It also has a basin in the city centre, at Sighthill (where a chemical works was strategically located in the mid 19th century).

"There were no natural water courses for development drainage to discharge into and the sewer system was nearing capacity"

Glasgow is a soggy city and one with almost no natural drainage to spare, many water courses having been incorporated into the sewer system as the city developed. The canal offers an additional source of catchment for excess surface water during periods of rain. The remainder is carried through the sewer system which is operating at near capacity. Any further stress - for example, through additional household sewage from sizeable development – is likely to result in flooding.

The upshot is that a number of sites in good strategic locations around the city region cannot be developed because of the flood risk they present. It’s a problem that’s especially prevalent in the north of the city, where the Forth and Clyde deviates from its main channel to Pinkston Basin, snaking around five communities that score highly on the Scottish Index of Multiple Deprivation and which would benefit from regeneration: Sighthill, Dundashill, Cowlairs, Hamiltonhill and Ruchill Hospital.

“What we've seen in north Glasgow is the historic water courses have been incorporated into the converter system,” explains David Hay, group manager, project management and design, development and regeneration services at Glasgow City Council. “So there were no natural water courses for development drainage to discharge into and the sewer system was nearing capacity.”

How to address the challenge? “We wanted to explore whether not we could use the canal as the conduit to transfer water from these sites to the River Kelvin,” continues Hay. “And what is unique about this section of the canal is that it’s referred to the ‘summit pound’ on the Forth and Clyde Canal.

“So the canal from Sighthill all the way out to lock 21, in Maryhill in the west end of the city, and then all the way along to beyond Kilsyth is all at the same level. There are no locks in that section of the canal and it's the highest point on the canal system.”

Smart thinking

In normal conditions, the canal is capable of carrying excess surface run-off. But the barrier to building canalside in the five communities is the one-in-30-year storm that would cause the canal to flood. There is, according to Hay, a 3 per cent chance of this happening in any given year.

If the canal were able to carry the quantity of excess surface water caused by the one-in-30-year storm, that would open up 110 hectares of land for development in areas that are close to the city. Basically, it’s a process of opening and closing locks and sluice gates at strategic points in the canal system at the right time.

Trying to do this manually would be logistically difficult and very fallible – you’d need to be keeping tabs on exactly what’s going on at multiple sites simultaneously. So the council, working with its partners Scottish Canals and Scottish Water under the umbrella of the Glasgow Metropolitan Strategic Drainage Partnership came up with a technological solution that they believe to be a European first – a ‘smart canal’ in which sluice gates are opened automatically in response to anticipated water flow.

Essentially, a network of 20 sensors is placed along the canal at strategic points to provide constant feedback to a central server about water levels, flow and quality. Meanwhile, the server is also receiving information from a live feed from the Met Office.

“It’s running that rainfall data through a live hydraulic model which will determine whether or not the intensity of the rain across these development sites in north Glasgow is such that we need to create additional capacity in the canal,” explains Hay.

In the event of heavy rain being forecast, the system will automatically open the three locks required to reduce the amount of water flowing into the Forth and Clyde Canal (from a feeder reservoir and another canal) and to enable water from the canal to flow into the River Kelvin. By doing this before the storm hits, the risk of flooding across the system is removed (there may be a gap of a day between heavy rain and a noticeable increase in the water level of the Kelvin).

"Not connecting these sites to the combined sewer also allows you to regenerate other vacant and derelict sites within the north of the city"

Combined with additional flood protection measures at the targeted sites, such as sustainable urban drainage systems, this would enable the canal to soak up the excess water created by the one-in-30-year storm. A 10 centimetre drop in the water level of the canal would create capacity within the canal for an additional 55,000 cubic metres of floodwater.

“The reason that we are working at 10cm is that at 10cm it still allows the majority of boats to be able to navigate the canal and also it reduces the risk of the canal embankment becoming unstable,” explains Hay. “What we're saying is 2,500 homes and 53,000 meters square of commerical space,” he adds. “Not connecting these sites to the combined sewer also allows you to regenerate other vacant and derelict sites within the north of the city that have no option but to go to the combined sewer.”

The smart canal is currently under construction.

"What's not to like about that?"

Forbes Barron, Glasgow City Council’s head of planning, development and regeneration services, stresses the importance of water management to opening up the city. “Without a good strategic approach, that leads potentially to people living in less sustainable locations which is not anyone's interest. So the canal represents a way of diverting water in the way it should be.

"The canal is effectively the balancing point using technology to then divert it into the Kelvin or the Clyde. What's not to like about that?”

The Glasgow Metropolitan Strategic Drainage Partnership is working on 14 schemes to manage drainage across Glasgow city region, ranging from SUDs schemes to a waste water tunnel, reservoirs for floodwater and an underground pumping station.

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