A forecasting tool has been launched to give notice of urban floods.
Forecasting technology developed by hydraulic modelling specialists Richard Allitt Associates can give street-by-street flood warnings to councils.
This will enable them to deploy sandbags and other flood defences before water rise.
Richard Allitt chairman and managing director Richard Allitt said flood forecasting for major rivers had been in place for many years. But he said that warnings could be days in advance rather than hours as river levels rise quite slowly.
He said the new system could be used in urban areas where conditions could sometimes create flood risk with as little as six hours’ notice.
“The difficulty in the past with prediction in urban areas has always been the very short timescale and this now allows us to [manage] that,” said Allitt.
The system uses existing integrated catchment management software to model the urban environment from sewers to highway drainage and manhole positions.
The model is integrated with data from the Met Office’s Nowcast forecast system as well as with sewer state and tide data. It runs hourly simulations based on predicted rainfall.
The frequency of the simulations is increased to every 15 minutes if a storm is forecast.
“It’s a full simulation so, for example, we can model every manhole in the city so we will know exactly which manhole or which street will flood, so it’s very precise,” said Allitt.