Predictions on the threat of coastal flooding are leaving out a vital ingredient, claims a University of Hull scientist in the UK . A team led by Professor Dan Parsons (pictured) in the Department of Geography, Environment and Earth Sciences is recreating realistic seabed conditions in the Total Environment Simulator at The Deep, Hull, to investigate the interaction of sand, mud and biological ‘goo’. It is hoped that the findings will contribute to more precise predictions being made on coastal flooding globally.
The project is the first of its kind to introduce goo (or microscopic biological matter) into the equation as it seeks to better understand the impact of climate change on our coasts and estuaries, and help predictions of flooding from storm surges such as the catastrophic North Sea Flood that claimed the lives of 1,836 people 60 years ago.
When water flows over the seabed, it shapes the sediment into wavy features, such as sand banks, mud banks and ripples, which form important barriers around coastlines.
Globally, present coastal evolution and flood prediction models are based on seabeds that are made purely of sand. But, says Prof Parsons, when mud and goo are introduced, the predictions change completely, rendering today’s calculations far too generalistic.
“Bearing in mind that most coastal seabeds are a mix of more than one type of sediment, it is very important for us to find a more precise method of prediction, especially as sea levels are rising,” he says. “How these mixtures, that include fine materials, are moved by water currents is key to this understanding.”
The scientists are adding mixtures of sand, mud and xanthan gum (the latter to replicate the goo) to a large cement mixer before pouring it into the simulator and recreating a variety of water flows over the mixtures. This is revealing how the seabed is shaped with varying levels of the three components and in varying water conditions.
Prof Parsons adds that there was almost a complete lack of scientific knowledge concerning seabeds consisting of mixtures of sands and muds. “This knowledge is vital to helping us understand how natural mudflats and beaches will respond to the changing forces of the tides, wind and waves that will result from climate change and sea-level rise,” he says.