Can a complex canal system solve Britain's water woes?
Can a radical spin on the water grid save the nation from drought and slash the cost of long distance power transmission?
Late last year David Weight, a senior consultant at AECOM, released a paper outlining ambitious plans to build a large canal with electrical power down the spine of Britain. With a construction price tag of some £14bn, the multi-functional canal would transfer water from the Scottish Borders to the south of England, offer a sustainable alternative to road and rail freight, and eventually co-exist with high voltage DC lines.
Weight says the UK government is currently considering the proposal and is busy rallying support from potential stakeholders, confident that the multi-purpose waterway is economically viable. His vision is inspiring, his ambition is admirable, but at a time when the UK has narrowly missed its third recession in five years, is he serious? Absolutely.
"We have a lot of unmet water demand in the south-east and east of this country for farming and irrigation and we're also facing the problems of population growth and climate change," Weight says. "There is a long-term fear of water shortages in the future and I am very concerned about our resources in 20 to 30 years time. We're in the process of proving our concept to government and stakeholders; I'm confident this project is do-able."
Weight hasn't confirmed the final canal route yet. Several routes have been considered including the the Grand Contour Canal outlined by JW Pownall in 1942, along the 310ft contour from the Scottish Borders to the south east.
"This route would need to drop a bit across the contour to promote sufficient flow... we then wouldn't require pumping and this would be relatively economic," he says. "The original Pownall route meandered significantly west of Leeds. Such an east to west link would be fantastic but would also require tunnelling and a deep gorge so we're finding easier routes going to Sheffield and west of Nottingham. These would be cheaper, more above ground and more desirable."
His team is now finalising routes using in-house knowledge of existing and potential freight transport. Geographical information systems software is also being used – across billions of iterations – to cost different levels with possible embankments, cuttings, aqueducts and tunnels (see 'The AECOM proposal'). To date, costs for the canal alone figure between £11bn and £18bn and a first phase extending from Kielder reservoir down to Leeds would cost around £3.4bn.
Water transfer aside, Weight envisages HVDC lines running along the length of most of the canal and broadband fibre-optic cables beneath towpaths. And by linking to existing canals, this 'mother' canal could also provide a route for biomass transport to inland power stations.
Feeding the south from the north
But while AECOM's multi-functional canal plans are breathtaking, the notion of building a 'water grid' to transfer water from the 'wetter north' to 'drier south' has been aired and shelved time and time again.
In 1973, the Water Resources Board recommended a complex system of aqueducts and pipelines to do just this but prohibitive costs didn't even warrant a feasibility study. In 1992 Michael Howard revitalised the idea, only for it to fall flat until Defra commissioned another investigation in 2006, where yet again it was labelled cost ineffective and highly energy intensive.
But in early 2012, many months of low rainfall brought the threat of drought to the UK. A wet summer ensued, but the near-miss highlighted the simple fact; the UK is not water-secure. In his much publicised column in the Telegraph, London Mayor Boris Johnson called for an improvement of current canal networks to bring "surplus rain from the mountains to irrigate and refresh... the south and east". AECOM's proposal and passionate debate followed.
WaterWise, a UK not-for-profit organisation promoting water efficiency, describes the concept of a national water grid as an outdated Victorian approach to a 21st century problem.
"It is now clear that massive infrastructure projects are not the way to go," says managing director Jacob Tompkins. "Climate change means there could be less water in Scotland and what happens if we have drought in the north west? Can we reverse this grid? No. Once it's built you would be left with a very inflexible piece of infrastructure."
Other organisations, including the Environment Agency and the Institution of Civil Engineers, have raised concerns over mixing different chemistries from north and south waters. Could this damage local ecologies?
Weight's responses are candid: "A huge drought in Scotland is unlikely and we can use a conduit in the canal to keep [incoming] water separate and then treat on delivery."
But despite the solutions, can such a mega-project really be feasible? Weight asserts most organisations, including the UK Canal and River Trust, are 'open' to his latest proposal, but as Richard Rutter, head of enterprise at the Trust says: "We still need to understand if this is feasible. This is not what we're doing at the moment; we're focusing on what we've already got".
Michael Norton, Professor of Water Engineering at Brunel University and Global Water director with AMEC Environment and Infrastructure, is concerned. Pointing to the Great Man-Made river in Libya that supplies fossil aquifer water to the Sahara desert he says: "Yes, long distance transfer of water is definitely do-able, but does Libya have alternatives? Water transfer is technically viable, but is it economically viable?"
Standing as chair of the Institution of Civil Engineer's Expert Water Panel, Norton's answer is no. In the the ICE's recent 'State of the Nation: Water' report, Norton and colleagues wrote: "Such a solution is too costly, environmentally damaging and too grand a design for the need."
But what exactly does the ICE propose instead? A many-pronged approach.
First it urges stronger collaboration '' including water transfers – between water companies, which Norton asserts could be quickly achieved by simplifying pricing rules for water companies.
"A water grid is impractical due to huge capital costs and associated energy costs but that's not to say we shouldn't see more interconnection between adjacent water companies," he says.
Small-scale water storage solutions
Crucially, the ICE advocates smaller-scale solutions, scattered across the country, with an underlying emphasis on storing water rather than moving it.
"We should be looking at storing more water from excess rainfall, generally during the winter months," says Norton. "And not just reservoirs, we can make use of smaller scale storage in our aquifers and also develop sustainable urban drainage systems to capture water and return it to the ground."
According to Norton, grey-water recycling – capturing and filtering bathing and washing machine water to flush toilets – would reduce household water consumption by a third while recycling waste water from treatment plants would also relieve stretched supplies. And metering is a must.
As he points out, most households pay only £1 per day for unlimited water, which doesn't reflect the costly treatment process to make it potable let alone its true value. Meters would allow consumers to track water use while discretionary tariffs could reward low usage.
This more distributed approach has many supporters, including Waterwise director Tompkins.His organisation is rolling out thousands of water efficiency retrofits on toilets, taps and showers across the country. And he's convinced smart communications networks linking consumers and utilities should be used to optimise water use. "It's nice to have a big digger and say 'look, we're a new generation of Brunel'," he says. "But today Brunel would be looking at micro-sensors and intelligent houses, rather than digging a massive canal."
Diggers or not, can a pot pourri of storage and efficient water use really quench a looming water crisis? Norton thinks so.
"Yes, we're talking big numbers. The UK has on average 250 cubic km of rainfall a year; about 150 cubic km of that ends up in the sea. On average, we only take around 10 cubic km a year out of our water systems... so we still have this large available water resource," he says. "In a dry year, we do not have these numbers, which brings us back to the utterly compelling view that we must store more of our excess water. We tend to think we've exhausted our available water when there is clear evidence to the contrary."
Still, many industry players would like to see a potential water grid investigated further. As part of its report 'Infrastructure: The Routemap For Growth', the UK Civil Engineering Contractors Association (CECA) called for the commissioning of a feasibility study on the bulk transfer of water across the UK.
As Alasdair Reisner, director of external affairs at CECA puts it: "London was perilously close to running out of water just weeks before the Olympics last year, and that would have had billion-pound consequences for the economy. We've got to look at the engineering challenges and act."
Reisner wants to see a "sensible and non-political" feasibility study and consider alternative options. "We need to get all the evidence on the table, pick a solution and get on with it," he says.
And Weight is steadfast in his conviction that greater action is needed. "It's a great aspiration to work with what we've got but it will only take us so far. It's not going to be enough to cope with the problem we're facing in decades to come."
Pushing the canal proposal
So where next for his proposal? According to Weight, DECC chief scientific adviser David McKay has received his visionary canal proposal and distributed copies to relevant departments including BIS and the Department for Transport. "We're now waiting to hear," he says.
Political support and funding would send positive signals to potential stakeholders including water and power companies, and then progress could really take place.
"I could spend years discussing this with people who could have a stake in it, there are hundreds, but backing from government would give potential investors and stakeholders the confidence that this would get more backing in the future," he says.
At the time of writing, Weight was entering discussions with UK-based Peel Ports – the real estate business owning Britain's second largest group of ports – to discuss the best size and scale of a new canal.
"Many have said our problems with water don't justify something like this, and I'm not saying it is justified on water supply alone," he says. "But when you bring in transmission cables, freight transport, the value of land – people will pay at least 40 per cent more for a property by a canal – these values add up."
Further afield, construction of the mighty China-based South-North Water Transfer project, set to eventually divert 44.8 billion cubic metres of water annually from the Yangtze to north China, is well underway. The first water is expected to reach the north later this year; testament that mega-projects and national grids can and are taking place. However, still many remain uneasy.
As Waterwise's Tompkins concludes: "What message does any water grid send to the consumer? Yes, we've had a big drought but don't worry, leave it to the civil engineers and you can use as much water as you like."
Water issues the new canal system will solve
According to Defra, by the 2050s summer river flows could reduce by 35 per cent in the driest parts of England and by 15 per cent in the wetter river basin regions in Scotland. As the Institution of Civil Engineers highlighted in its 2012 'State of the Nation: Water' report, this will place severe pressure on today's water abstractions, particularly in London and the south east where population is predicted to increase 23 per cent by 2035.
Growing populations will require more water from public supplies. But at the same time, agricultural and industrial demands will rise as more people consume more food, energy and goods. And while today farmers partly rely on rainfall, they will turn to water abstracted from freshwater lakes, rivers and aquifers for irrigation as summers get hotter and drier. This is the very same water that feeds the public water supplies for the nation's growing population, and is set to dwindle rapidly.
The AECOM Proposal
The AECOM water grid is, to date, the only proposal for large scale water transfer that doesn't require costly and energy-hungry pumping. According to AECOM consultant David Weight, the 24m wide, 4.5m deep 'mother' canal would flow at 0.6mph and could be built in several separately funded phases.
The stretch from Kielder to the Leeds area, for example, could link to existing canals and rivers, which could be used to supply water and biomass to inland power stations in North Yorkshire. A low-cost option could be to supply water to the canal network and the River Trent which would then serve other areas in the south and south-east through a 'cascade effect'.
HVDC transmission lines, supplying renewable electricity from the north to the south of England, could run along the route in a secure, accessible compartment within the canal structure. Cooling from canal water could improve transmission efficiency, enabling smaller cable to be used and reducing capital costs relative to laying down heavily armoured undersea cables.
Plans to route broadband communications cables underneath the towpath – fibre optic cables are already running beneath many towpaths – have been included and as Weight adds: "There would be ample height drop along the canal route so there is also scope for the generation of hydro power associated water and energy storage."
"What the Scottish independence referenda could mean for engineers and engineering on both sides of the border"
- What to Specialise in Electronics Engineering?? [03:02 am 03/04/14]
- Britain to have just one remaining coal pit by the end of 2015 [01:11 am 03/04/14]
- LV Generator Star point earthing - UK [08:35 pm 02/04/14]
- East West Rail - the Oxford to Bedford route [07:33 pm 02/04/14]
- Small nuclear power [06:06 pm 02/04/14]
The essential source of engineering products and suppliers.
Tune into our latest podcast