Idea's From The Keyboard Of Lucy: Stop Flooding By Making Rivers Longer

In winter rivers flood and with climate change bringing even more of a deluge down onto us, rivers fill up and break their banks and the Environment Agency says around 5.7 million homes and businesses in England are at risk of flooding so the usual solution is to either dredge the rivers to make them deeper or build up the river banks to make them higher but i have always thought there is another way and it all goes back to my school geography lessons and Oxbow lakes which means i did unbelievably take something in all those years ago.
An oxbow lake is a U-shaped river that forms when a wide meander of a river is cut off so if the bow is 20m and then through erosion the sides meet and the meander is taken away, the water flows directly straight through rather than having to travel the additional 20m round the bend first. If you have a 80 mile river and put a 20m loop in it every mile, the river would then be 81 miles long and the water would have further to travel so would take more time to get to wherever water ends up and not spill out over the sides of the banks.
The most famous UK river, The Thames, is 215 miles long and flows on average at 10 mph so it takes approximately 22 hours for water to flow from the start to the end but pop in the 80 20m loops along its course and the water will take 23 hours to flow the now 216 miles length and if you throw in a few kinks and bends that will slow it down even more.
The UK River which floods the most is the 73 mile long River Swale and that runs through the Yorkshire Dales so it would be easy to dig some loops, curves and swirls to increase the length and slow the water down but the key word there is 'easy' because obviously there must be some reason why nobody has done it yet, they just continue to go with constructing flood defences so maybe there is something i am missing.
My old geography teacher should be proud that something she said sunk into my teenage head all those years ago and i was listening to her whilst i sat at the back passing notes to my friends.