As we all return to work after the Christmas holiday, most of us can be thankful that the weather was reasonably kind compared to last year. Last Christmas, as energy supplies failed, residents in some 300,000 properties faced the prospect of exchanging their turkey dinner for a raw sprout salad. How many homes might have been affected if the power stations themselves had flooded? A reasonable thought given that last April, Daniel Johns, head of adaptation at the independent Committee on Climate Change (CCC) said, “It looks as though a significant portion of the electricity network is located in areas vulnerable to flooding.” Furthermore, the CCC’s 2014 progress report, Managing climate risks to well-being and the economy, states that climate change will lead to an increase in the number of infrastructure assets exposed to high temperatures, flooding, coastal erosion and subsidence in the coming decades.
Utility companies are making progress with increasing their assets’ resilience to flooding but there are still significant numbers of substations at risk. With limited funds available, assets have to be prioritised and this can’t be done without flood maps. For most utility companies, an inexpensive asset screening service is often the best way to start prioritising, but such screening is only as good as the maps used. So the first task is to choose a suitable flood map. The trouble with flood maps is that they are computer models so they don’t give definitive, unerring answers. Despite that, they are still the best tools available for indicating flood hazard so, how do you choose which maps to use?
There are many flood maps available and they differ in scope, quality and cost. So here are some points to consider. Check the quality of the hydrology, the hydraulic modelling software, the terrain model and the resolution. When were the maps last updated? Which flood perils do the maps include? At the very least they should provide river, surface water, coastal and groundwater flood data, with reservoir dam break and canal failure as important extras. Flooding from sewers would be a bonus but reliable data for this is hard to come by. Are defences included in the modelling? And in the case of coastal defences, has wave overtopping been modelled? Wave overtopping caused much of the damage in last year’s Windstorm Xaver and needs to be modelled to get a truer picture of likely outcomes.
There is no doubt that the country needs to invest massively in flood defences but with government funding being insufficient for the task, infrastructure managers must rise to the challenge. JBA Risk Management has a complete suite of multi-peril flood maps for the UK and Ireland which tick the boxes. We’d love to hear from you.
This is an edited version of an article which was first published in the 31st October edition of Utility Week.