This seems like a deliberate attempt to explain some of the less obvious ways of dealing with flooding …

Andy Croxford, 20 October 2015 Environment Agency    Flooding can occur from many different sources. We saw this in winter 2013-2014 when the storm surge caused flooding on the east coast, there was widespread river flooding across many counties, chalk springs started to flow leading to groundwater flooding and in many places surface water flooding was caused by short intense rainstorms that overwhelmed drains and sewers.

There are many ways to reduce the impact of a flood. We can build walls and defences to provide a barrier against flood water; install property-level protection such as flood boards across doorways; maintain the watercourse channel differently; deploy temporary barriers; provide flood warnings and develop flood plans. Alongside these traditional forms of flood risk management we are starting to see greater use of natural processes to reduce flooding. To read more:

https://environmentagency.blog.gov.uk/2015/10/20/engineering-with-nature-to-help-reduce-flooding/