More than 40 million Americans may be at risk of severe flooding. A study by the University of Bristol, published in Environmental Research Letters, used predictive methods to analyse the threat of river flooding over continental America.

The findings exclude coastal areas, which could potentially add millions to an already steep figure. The findings are triple previous predictions shown in existing regulatory flood maps produced by the Federal Emergency Management Agency (FEMA).

This massive increase in predicted ‘at risk’ areas is due to a higher land coverage being studied, previously only 60 percent of the continental US was accounted for, and greater precision of analysis that has allowed the risk of flooding from smaller streams to be estimated. The predictions made in this paper correspond to the risk of Americans to a ‘100 year’ flood: a flooding event that has a one percent chance of occurring in any given year. It is crucial areas at risk of flooding are more accurately mapped and understood, with a “critical information gap” needing to be filled.

An acute awareness of areas at risk can lead to preventive measures being put into place; this would lead to any damage caused by extreme flooding to be lessened and the subsequent costs, economically and socially, to be reduced. The cost of floods on the US government is roughly $10 billion per year. As population sizes continue to grow, it will be of paramount importance that data is used to implement appropriate floodplain management schemes and to levy funding for developments that are well prepared for flooding potential.

With correct management, floodplains can offer “high quality habitats for wildlife, … outstanding recreational opportunities for people, and [can help to] improve water quality,” says the paper’s coauthor Kris Johnson – this offers yet another incentive for improved management.

Although this study seemingly offers a bleak outlook, it is important to remember, with the correct utilisation of information many of the negative impacts can be bypassed and some potentially positive and beneficial possibilities, that can result from flooding, can be brought to the fore. The onus is on those in power to employ this information before it is too late.