As a teenager I spent a day in a field in Kent waist deep in water with a large ruler and some string. I was, along with a group of equally disgruntled teenagers, measuring the gradient of the bend in a river. After five hours of rain, soggy sandwiches and far too much water in our wellies we concluded that the river was officially ‘meandering’: imagine our joy. Since then, I must admit to have given little thought to rivers. Tom Fort would be disappointed. He adores them. So much so that he is annoyed that there is no official name for his passion: fluviophilia and river-love are unsatisfactory, as neither captures the sheer breadth of his devotion.