TRCH

Flood Plains Modelling with Ian Bartlett

30 December 17 words: Gav Squires
photos: Tom Morley

As the days get darker and the nights get colder, the rain is sure to fall, which in some parts of the country may mean the misery of flooding. One local man, Ian Bartlett, has been creating models to help communities understand how to prevent flooding in the first place...

Ian started creating educational flood management displays back in 2012, but when authorities like the Forestry Commission and the James Hutton Institute in Aberdeen wanted better, more realistic and longer-lasting models, he had to go back to the drawing board. After finding a place at Primary Studios, he set about starting a project that was a unique mix of art, engineering and science.

Ian describes his scale models as looking like "an old western saloon bath with a landscape set into it" and each one contains nine food-grade misting nozzles which enable them to simulate rain. The landscape itself is fibre glass covered in a digitally printed synthetic material which doesn't rot; a necessity as they’re getting wet and dried off again several times in a week. The models act like the ground, and absorb some of the water before it starts to flow over the model. "There are hills and valleys and tributaries engraved into the surface,” Ian adds, “and it does start to flow like the rain catchment does."

Ian has built six models in total, and there are two models in each set: a "good" one and a "bad" one, which demonstrate what can happen when flood and water management is handled well and what happens when it isn’t. Where there are well looked after pieces of moorland, it is represented by sponge in the model to absorb the water. "That sounds like cheating,” says Ian, “but it’s actually how it works. They absorb a certain amount of the water that’s sprayed onto the model, and that will never reach downstream." In real life, this would either evaporate or soak into the water table so that it wouldn't be an issue downstream.

Further down the slope, there are boundaries of trees either side of the tributaries with roots that impede the water coming off the landscape and give the shrubbery a chance to catch the water. However, on the bad model, these boundaries are done away with, simulating land that had been optimised for agriculture. “The length of the grass has a big effect on how quickly the water runs off into the edge of the field," explains Ian. “It doesn't stop it running off, it just impedes it, and it takes its time to come downstream again."

In the lower reaches, there are embankments in the corners of fields. "It can actually store up a bit of a dam,” Ian tells me. “It's very subtle, but it's on the good models and not on the bad ones. So you can see there's a picture here; in the worst case, the water's just running as fast as it can off the slopes. There's no absorbency there, it's not hanging around long enough to soak into the landscape." Then, right at the bottom is the floodplain itself. Ian adds: "If the levels are so high, the main water course has meanders in it, which slow it down again rather than being straight; that happens on a lot of water courses where they're trying to get it away fast."

He also says that there is "a ‘wash-out’ zone where the water is allowed to flood certain areas of fields as a temporary storage, to give the capacity for the volume of water. But why? "Because once it hits the main river that's heading out to sea, that's when the problems really start to accumulate," says Ian. “It’s a process of accumulation; incremental problems mount up to quite a lot in the end. It all takes money to resolve and someone has to justify that."

Hopefully, this will all demonstrate the need to look after our floodplains, which used to be prevalent before we co-opted them for our own purposes. As Ian says: "There has to be a balance between the two; you can't expect to ride roughshod over nature. We've tried to erase the forces of nature and say that we want all this land as productive land. Well, you can't have everything."

Ian describes some of the difficulties that he’s had producing the models, saying he's "had to learn a lot about glass fibre and pattern making to make the original base unit." Fortunately, he’s been able to use the facilities down at Hackspace, which have been invaluable for things such as laser cutting and using their lathes. He’s also had to overcome toxic fumes and now feels that he is "possibly the only person that has resolved all of the issues to do with demonstrating these things" which makes him hopeful of landing more future commissions.

The aim of the models is to educate the communities that live in areas at risk of flooding, from local government to farmers. And it turns out this education is highly necessary. A woman who was at one of Ian’s demonstrations thought she had all the answers: "Oh, you just need to get a digger in, clean all the riverbeds out and get the water moving."

"That's the worst thing you can do,” countered Ian. “It just moves the problem downstream. It was a destructive way of coping with the problem. With the increasing rainfall that we're seeing, you need to engineer some of the natural solutions to impede the flow."

The models can be displayed anywhere from schools to fairs and village halls, and the two models side by side give a really effective display of the dangers associated with poor flood management. People can actually see that for the same amount of water, the village on one of the models floods and on the other one it doesn't.

In recent times, writers like George Monbiot have been very vocal about the need to look after our floodplains better in order to prevent the scenes of people's homes being flooded that have been so prevalent in news reports. Hopefully, Ian's models will be able to help educate all of the stakeholders along the river and fewer people will be in danger from such terrible tragedies.

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