Playful floods

By Sanita Vetra-Carvalho

Flooding is no fun for those who have been affected by it. However, being able to ‘experience’ flooding in some sense is one of the best ways to communicate flood risks as well as the potential solutions to audiences ranging from school children to decision makers within industry and government sectors. Equally important is to be able to build physical models based on simplified reality which can be used in research to learn about less known aspects of flooding such as extreme events with long return periods, study behaviour of the water, or to develop and/or improve numerical computer models used in producing flood forecasts. As such, flood demonstrators have an important role to play in people learning to live in the world where floods are predicted to increase in both frequency and intensity in the near future due to climate change (Sayers et al, 2015).

Below I have summarised portable flood demonstrators known to me developed and available within the UK. These range from completely physical to virtual reality flood demonstrators, and will be presented in this order for no particular reason.

The first one that comes to my mind is Wetropolis developed by Professor Onno Bokhove and his team at University of Leeds. Wetropolis (Figure 1) is an interactive toy model of an extreme rainfall event demonstrating how such an event can lead to flooding in a city. It is aimed at both the general public as well as scientific community effectively and realistically demonstrating city flooding. From the scientific perspective Wetropolis is a very interesting and useful tool because the design of the river channel and rainfall model is based on mathematical techniques and the occurrence of flooding is determined by rainfall of the current and previous days, as in the real world.

Figure 1. The schematic of the Wetropolis flood demonstrator. Image taken from http://www1.maths.leeds.ac.uk/mathsforesees/edin/MFEdinb2016s.pdf

To study and demonstrate the key principles of floods and coastal risk management JBA Trust has created a range of physical models to demonstrate. Their models range from a portable wave tank to a trailer-mounted hydraulic flume demonstrator, and are very effective in visualising and understanding water behaviour in simple river channels and coastal regions.

The JBA Trust wave tank effectively demonstrates the performance of various coastal defences under different wave regimes including beach during a storm surge. It is a very simple, effective and portable wave tank demonstrator.

JBA Trust hydraulic flume demonstrators range from mini to trailer-mounted versions. All of which simulate simple channel flow driven by a system of re-circulating pumps, and feature scale models of typical engineered structures such as bridges, weirs, debris screens etc.

Figure 2. The JBA Trust free standing hydraulic flume. Picture taken from http://www.jbatrust.org/how-we-help/physical-models/hydraulic-flume-free-standing/

Another visually effective way to physically demonstrate flooding, its causes, effects and to test various flood defence mechanisms is using a sandbox and water. While the basic sandbox is cheap to make it can be messy and tedious to work using physical water. This issue is alleviated in the recently developed augmented reality sandbox (AR SandBox). Originally developed by Oliver Kreylos at UC Davis it combines the physical sand in a box with 3D computer visualization tools which simulates the rain and water flow.

Figure 3. An AR SandBox at the GameScienceCenter in Berlin, Germany. Photo by Sjors Houkes.

The AR sandbox is a very interactive way to understand how topography affects water moving through a catchment. Here participants can assemble real or hypothetical topographical environments which are then directly overlaid with an elevation map and contour lines. The rain in the AR sandbox is simulated by holding a hand over the sand and in real time observing how the virtual water moves in the catchment. The effect on water due to changes in the land can be explored by moving the physical sand in the box which will automatically adjust the augmented reality. Currently there are more than 150 AR SandBoxes worldwide adapted for wide range of audiences including JBA Trust, River Way Trust, University of Southampton and many others (explore more here). You can also build your own AR Sandbox following instructions here.

Stepping completely into the virtual reality there is the Flash Flood game which demonstrates the effects of flash flooding due to extreme rainfall events. The game was commissioned by NERC Flooding from Intense Rainfall (FFIR) programme to help share their research and produced by SeriousGeoGames. Flash Flood is based on a real intense rainfall event from 2007 in Northumberland, vividly highlighting the dangers of flash flood, how rapidly it forms, and how damaging it can be. It challenges participants to survive a flash flood. This tool is open access and can be downloaded from the mentioned site for free.

Figure 4. Flash Flood being tried out by Prof Brian Golding at the Flooding From Intense Rainfall annual conference in 2017. Image taken from http://blogs.reading.ac.uk/flooding/2017/12/08/the-ffir-annual-conference/

The same SeriousGeoGames have also developed TideBox (previously known as a Humber in a Box), which merges a research hydraulic model with a gaming engine. Here a hydraulic model is used to simulate long-term development of the Humber estuary and players can watch the tides and flow of the water in 3D. A player can increase or decrease the sea level to see how flood risk might change in the future.

This is by no means an exhaustive list of portable flood demonstrators available in the UK and if you know of or are in a possession of a demonstrator not mentioned here I would love to hear about it, you can email me.

References

Sayers, P.B, Horritt, M, Penning-Rowsell, E, and McKenzie, A., 2015. Climate Change Risk Assessment 2017: Projections of future flood risk in the UK. Research undertaken by Sayers and Partners on behalf of the Committee on Climate Change. Published by Committee on Climate Change, London.

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