THE RIVER

At school, we are taught that rivers always flow down to the sea. It is a basic law of nature and a key part in the water cycle – rainwater runs down a hill and into a river, travelling out to sea before evaporating and condensing into a cloud that rains back on the land and pours into the river, completing the cycle. But it is not entirely true.

In fact – as if defying gravity – water in many of Britain’s rivers actually flows inland half the time, travelling uphill. The reason this happens is because these rivers are ‘tidal’, meaning that when the tide rises at sea, water is forced up the river. There are two effects from this happening; firstly, the level of the river rises