Engineers build more questions than answers with the Natural Grid

A few weeks ago, I had the opportunity to head to the first in a new lecture series run by the Thames Estuary Partnership. The lecture was called The Natural Grid and it was given by David Weight and Andrew Cripps from AECOM about an engineering idea they’ve worked on to address concerns about water scarcity in southern England, including London.

The basic premise of what they called the “AECOM canal” (perhaps not the most modest name) is a canal that runs north-south across the UK to transport water from Scotland in the north, which is not facing water scarcity (and is in fact having more trouble with flooding), to the Midlands and London south. Using GIS and contour maps, they have found routes for the canal that would be able to follow the contours of the land to travel by gravity, eliminating the need for energy-wasting pumps. The source of the water would come from Kielder Water, a reservoir that was built for industry that never came, so has excess water capacity.

The speakers gave a laundry list of benefits. The canal could provide flood relief by lowering the water levels to accept stormwater. All the way along the canal would be built a utility chamber so energy and broadband/data would have a right-of-way across the country. It would provide clean water for the agricultural Midlands and the ever growing population of London. There would be ecosystem benefits. There’s a chance that it could be used for marginal freight, like moving waste. There could be new or improved towns with waterfront access. More about the proposal can be found in their report The Case for the Natural Grid.

It’s certainly an interesting idea. And as London Mayor Boris Johnson made clear in the an article in The Telegraph in 2011 that inspired the AECOM team, at an elementary level, it makes sense–take water from somewhere where there’s a lot and move it to where there isn’t enough. As they said at the lecture, it’s not new technology, we’ve been building canals and aqueducts for centuries. But, also as they said at the lecture, it’s not the technology in question, it’s those pesky details like politics and funding (I’m paraphrasing, but that’s basically what they said).

But for me, the issue is that when proposing a grand idea, it’s your responsibility to think through the details. This isn’t the Roman or Victorian age when you could just build whatever you want wherever. There are major social, environmental, legal and political implications that must be considered and to treat them as details to be sorted out later seems rather irresponsible. Coming from Chicago, I am all to familiar with the long-term fallout of major engineering decisions. The reversal of the Chicago river was a major accomplishment 100 years ago and vastly improved water quality and public health for the city. But the multi-million dollar proposals to deal with invasive species transfer, the changing politics that have led to higher water quality standards and Illinois’ exemption to the international Great Lakes Compact & Agreement, not to mention stormwater management, water allocation and downstream water quality implications.

Hindsight is always twenty-twenty, though. And I do believe that the public dialogue that comes from debating proposals such as this generally benefit us as a society (more people talking about water!). I’m not necessarily against an idea like this, I just think there need to be more questions answered, lessons learned from other places and projects and honesty about what it actually can and can’t do before it can be seriously considered. So, in the spirit of public dialogue (and, well, if regulatory agencies and politicians are actually discussing it), the following are just a few questions that came to mind as I listed to the lecture. Thanks to the Thames Estuary Partnership for providing a forum for discussion!

  • How would they handle land acquisition throughout the length of the proposed canal? It’s one thing to use GIS data to pick ideal routes based on contours and land use type, but it’s another to deal with actual landowners. Particularly if this happened to be a private enterprise without ability to seize land.
  • What are the implications for existing wildlife and ecosystems? What happens to wetlands, habitats, migration paths, etc. that the canal would cut through? Would there be plants along or aquatic wildlife in the canal?
  • What about invasive species? Like the Chicago Area Waterway System, would it become a superhighway for invasive species? Unfortunately, the answer they gave was a fairly dismissive “invasive species are coming anyway, this might just make the come faster.”
  • How would long-term maintenance be handled? Infrastructure maintenance is already a major problem everywhere. Again, their answer was fairly dismissive, stating that existing canals had maintenance problems because they were made with clay and this would be part concrete, part bitumen.
  • Which raises the question, if the canal is that channelized with hardscape, what ecosystem benefits does it really have?
  • What about management of the system? They talked about the ability for the water level in the canal to be lowered to allow space to handle flood waters. In Chicago, the waterway system is managed entirely by the Metropolitan Water Reclamation District of Greater Chicago (as I described in a past blog post). Would there be one entity to manage it, if so who, and if not then how?
  • Which begs the question, who would own/govern the system overall? Water in the UK is no longer nationalized, so the national government doesn’t really have the power to do it. Would it be a partnership between private water utilities? Would it be a private entity that bought and sold water between water utilities? Would it involve a public private partnership?
  • On a related note, who owns the water at the reservoir that would be the headwaters for the canal? Presumably that’s owned by a private water company. How would that transfer be handled?
  • How would it help towards stormwater management? If the canal itself is elevated for safety reasons, how would flood waters be redirected into it?
  • What are the implications for the Thames Estuary? The event was put on by the Thames Estuary Partnership, presumably not as tacit support for it, more for public interest, but the speakers didn’t explain how it may or may not affect the estuary.
  • What are the water quality implications from potential freight or waste traffic? What about from raising the water temperature due to cooling adjacent energy cables?
  • And, of course, the biggest question, who would pay for construction and long-term operations? And depending on who does, if there is any public money involved, what is the cost effectiveness compared to other ways of addressing water scarcity, such as demand reduction, reducing leakage, wastewater and local stormwater reuse and even desalination?

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