On a recent visit to environmental and river works in my constituency, I was asked if I knew about total water catchment management. It was presented as some new breakthrough, based on understandings of the patterns of water movement. Apparently it includes the perceptions that you need to manage water on a water basin basis, and that you need to consider what happens to the water if you speed its passage upstream to avoid flooding when that water arrives more quickly downstream.
I expressed surprise at this. Water has always been managed on a water catchment area basis since I have been involved in public policy. Our water companies were designed around water basins. There have been few attempts to transfer water from one catchment to another. The most famous was the decision to supply Birmingham from new reservoirs in Mid Wales, which caused controversy. Debates about creating a national water grid have not resulted in the creation of one.
I would also have thought it had been well understood by past generations of managers that if you solved the problem of flooding by improving capacity to move the water on upstream you could do more damage downstream unless you also made provision there for fast transit or storage of excess.
It is true that much of the rain falls in the more lightly populated parts of the north and west of our country, whilst more people live in the drier south and east. There is some movement of water to those places by the Thames and other rivers, but the south has had to build reservoirs for storage on a considerable scale and has put in desalination capacity as well to have sufficient water. It is important to recognise the need for more water capacity in the south and decide which is the best value and best environmental means of providing that capacity. The UK overall is not short of water and overall gets plenty of rain. There remain important issues about supplying enough drinking quality water during dry periods in the drier heavily populated parts. More water storage is one answer. More water transfer would be another.
Meanwhile water management is crucial to controlling flood risk. Given the extent of building on flood plain, it is becoming ever more necessary to engineer solutions to safe water transport and storage during times of heavy rainfall.