A guest blog by Bryan Hopkins.
A few weeks ago I picked up my grandson from school and on the way home he asked me if I knew the names of the rivers that flowed through Sheffield. “Well,” I said, “there is the Sheaf, the Porter, the Rivelin, the Loxley and they all flow into the River Don which then flows to the sea at…”. At that point I realised that I did not really know what happened to the Don, so I pulled out a map to find out.
I worked out that after Doncaster it reaches Thorne and then follows a more or less straight line until it reaches Goole, where it then joins the Ouse and flows into the Humber Estuary.
Disappointed by my ignorance I decided to go exploring, so I took my bicycle on the train to Goole and cycled back to Sheffield, following the river as closely as possible. The first thing I noticed was that for the first 15 miles, I cycled in dead straight lines. Now, this is not normal. As rivers get close to the sea they should meander from side to side as they slow down. The Don does not do this because the current river is artificial, cut in straight lines by Dutch engineers in the 17th century to make it easier to drain the surrounding land and to make navigation possible.
The second thing I noticed was that it was also often difficult to actually see the river as it was hidden behind high berms, embankments built to stop the river from flooding. This is necessary because drainage means that the level of the land has dropped and is virtually at sea level. In fact, it was only when I reached Stainforth, just north of Doncaster, that my GPS unit told me that I had climbed to more than 10 feet above sea level. This is, of course, no surprise to people who know villages like Fishlake which are more or less at sea level, and which are constantly at risk of serious flooding. The simple fact is that when land is at sea level, water cannot drain away.
Climate change is going to make this problem ever more serious. There is conclusive scientific evidence that the Earth’s temperature is increasing and global sea levels are rising. Current predictions from NASA suggest that sea levels could rise by as much as 5 feet by the end of this century. If this were to happen an enormous area of north Lincolnshire stretching from Gainsborough in the south to the Humber estuary in the north and from near Doncaster in the west to Scunthorpe in the east would be at a serious risk of inundation.
To misquote from the film Jaws, we are going to need a bigger berm.
As this extent of sea level rise is now inevitable we will need to invest heavily in building higher and higher walls to protect agricultural land and towns such as Goole, Thorne and Fishlake to name just a few. But this is just a sticking plaster. As the sea level rises, saltwater will penetrate further inland and this will have a negative effect on agricultural productivity.
Climate change is also going to mean increasingly serious and more extreme weather events such as intense storms and heavy rainfall on the Pennines, which will rush to the sea through rivers like the Don. Indeed, we have already seen this happening with the catastrophic Sheffield floods of 2007 and of Fishlake in 2019.
Rainfall run-off from the high ground into rivers is made worse when there are fewer trees to slow the flow of the water and allow it to soak into the ground. This is the situation we have in South Yorkshire where our moors have long been managed for the benefit of grouse shooting rather than to protect the environment. In urban areas, we have also covered hillsides with tarmac roads and driveways to houses to make life easier for the motor car. As this rainwater flows down into the Don, the level of water behind the embankments will get higher and higher as it finds it harder to flow to the sea.
This all suggests that as the decades go by that we will have to deal with an increasing number of serious floods, and will be constantly having to make decisions about whether to protect urban areas or agricultural land. So to try and reduce these problems we need to think seriously about prevention rather than protection, for example, by planting more trees across the high ground in the centre of northern England and regenerating peat bogs which can absorb water and store carbon dioxide. This will, of course, not be popular with communities who feel they rely on traditional activities such as intensive farming or grouse shooting but we need to be able to look at the bigger picture about the geography of northern England and the welfare of everyone.
The chances are getting ever stronger that when my grandson talks to his children about Sheffield’s five rivers he will be telling them that the Don flows into the sea at Doncaster.
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