Floods are more likely due to climate change and will claim higher economic costs unless action is taken to halt the damage to floodplains and restore some of their functions, warned the authors of the 12-month study – the first to paint a comprehensive view of England’s floodplains and their capabilities.

“We have ignored our floodplains,” said George Heritage of Salford University, co-author of the study the Changing Face of Floodplains, published by Co-Op Insurance on Thursday. “The changes to them mean water [from heavy rainfall] can flow much faster downstream, and can flow at the same speed as the water in the rivers.”

This accelerated flow has led to sudden and unstoppable deluges in recent years. For instance, Storm Desmond in 2015 affected more than 6,000 homes as rivers and streams burst their banks and spread water over floodplains. As these natural floodplains had been altered by man-made features, they no longer had the ability to store water, leading to rapid flows into urban areas which led to the devastation.

Storm Desmond caused more than £500m in damages, and misery for families excluded from their homes sometimes for months. The UK’s flooding bills are on the rise, with scientists warning of rocketing numbers of cloudbursts and periods of sudden and intense rainfall as climate change takes effect.

Floodplains act as natural “sponges”, soaking up excess water in their vegetation, forming natural buffers that hold back or divert rushing water after rain, and providing areas where rivers can breach their banks and wetlands can be replenished.

Intensive agriculture, increasing urbanisation, poor management of rivers and the draining of wetlands have left the vast majority of these natural features – many previously preserved for centuries by communities who understood their value – unable to fulfil these valuable functions, with some close to collapse.

Building on floodplains has been singled out for years as a key problem, but perhaps surprisingly was found to contribute only about a tenth of the damage in the study. Far greater is intensive farming, which has created artificially “smooth” and uniform landscapes, with hedgerows removed, large areas given over to single crops, wetlands drained and woods and grassland diminished. Farming accounts for nearly two-thirds of the loss of functioning floodplains, according to the study.

Natural floodplains cover about 5% of England, from upland areas and tablelands to low-lying marshes, such as the Somerset levels and the East Anglian fens. Once they were used for grazing for parts of the year, or left uncultivated. However, the exploitation of such areas accelerated in the middle of the last century, when wetlands were drained, hedgerows grubbed up and small farms gave way to bigger farming enterprises.

Today, the report found, 90% of England’s floodplains no longer function properly, with 65% modified by agriculture “meaning they’re now man-made, smoother surfaces”; 9% lost to urban and suburban building developments; 4% are now occupied by open water and 6% by semi-natural woodland and rough grassland; and only 0.5% is now natural or semi-natural wetland.

“It would be almost impossible to return the altered areas to their original state,” noted Heritage. “But it is possible to work with farmers to introduce features that would allow them to function better. …”

https://www.theguardian.com/environment/2017/jun/01/englands-90-floodplains-not-fit-for-purpose-study-finds?CMP=Share_iOSApp_Other