Flood forecasting for the 2014 Commonwealth Games

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Cast your mind back to the first weekend of August 2014. The Commonwealth Games are in full swing and, for most days, during July Scotland had been bathed in glorious sunshine as it welcomed the Games to Glasgow. For this final weekend Hampden Park was to be the centre of attention with the completion of the athletics and the final cycling event – numerous gruelling laps of the city centre as part of the final road race.

In Perth, home of SEPA’s arm of the Scottish Flood Forecasting Service, a team of flood forecasters were coming to the end of over two weeks of providing daily forecasts and briefings on the potential for surface water flooding across Glasgow.

Prior to this weekend the brief had been relatively straightforward with no flooding forecasted. However, the weather was about to change for the worse.

Rain during the Commonwealth Games (Photo courtesy of Allstar Picture Library)

Rain during the Commonwealth Games (Photo courtesy of Allstar Picture Library)

Scientific developments

Warning for the possibility of surface (or pluvial) flooding in towns and cities is one of the greatest challenges in flood forecasting. We’ve seen it on many occasions in the past in places such as Edinburgh, Inverness and more significantly in the East End of Glasgow in July 2002. This later storm resulted in the flooding of several hundred homes and left the city at a standstill as flood waters led to severe disruption.

One of the biggest fears in the lead up to the Games was for a repeat of flooding on this scale which could have meant events such as the cycling road race or marathon could not have gone ahead without putting some form of contingency plan in place.

We had been working with the research coordinators (CREW,  Scotland’s Centre of Expertise for Waters) over 18 months to develop a new and innovative approach to alerting for urban flooding.

The tool (Flood Early Warning System – FEWS – Glasgow), which mainly covered locations in Glasgow’s East End and the City Centre, was aimed at linking the potential for surface water runoff from intense rainfall to the risk of flooding to people, property and transport. The tool, developed by our project partners Deltares, the Centre for Ecology and Hydrology (CEH) and the Met Office, pulled together the latest in scientific developments and was operationally tested during the Games.

Example output from the Flood Early Warning System (FEWS)

Example output from the Flood Early Warning System (FEWS)

Flood alerting

A SEPA flood forecaster working on producing the guidance for the Commonwealth Games

A SEPA flood forecaster working on producing the guidance for the Commonwealth Games

How best to forecast and communicate the potential for flooding during the Games was something we spent several months considering. For river and coastal flooding we have tried and tested methods for anticipating and advising about the risk of flooding.

However, surface water flooding can be very difficult to forecast and to communicate. SEPA’s forecasters spoke to emergency responders and planners involved in the organisation of the Games to find out what they would require to help them prepare for any potential flooding situations.

They advised that a dedicated guidance document, to provide briefings on the timing, location and best and worst case scenario for potential flood disruption 12 to 24 hours in advance, would prove beneficial in helping their preparedness to potential flooding.

It was decided that a Surface Water Flood Forecast briefing document would be issued daily at 5pm to prepare for the following day – all to help with the planning and preparations for that day’s activities. This document slipped into a daily battle rhythm of forecasting, briefing, teleconferences and updates between our scientists, our meteorological partners at the Met Office, and those at the Games’ Multi Agency Control Centre in Glasgow.

                      

A pilot success

Lauren Addis, one of SEPA's flood forecasting hydrologists, at the Games.

Lauren Addis, one of SEPA’s flood forecasting hydrologists, at the Games.

So back to the final weekend of the Games. The forecast was for a spell of wet and potentially disruptive weather but, as generally with summer rain events, the likelihood of this occurring over Glasgow was low. As we got closer to Sunday though the risk of surface water flooding grew and the new tool indicated the potential for some minor flooding.

Thankfully as it turned out any disruption was only relatively minor with some flooding on the M8. However, our new targeted approach to alerting for surface water flooding was a great success in helping emergency responders keep one step ahead.

The final research report has now been published at CREW (www.crew.ac.uk/publications) and the Scottish Flood Forecasting Service plans to follow up recommendations and hope that similar capabilities can be developed across other towns and cities in Scotland in future.

This is one Commonwealth Games legacy which could benefit the country for many years to come.

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