River Thames
River Thames also known as River Isis in Oxford England is approximately 330 kilometers long (Britannica). It is the second longest river in the United Kingdom. River Thames flows from Gloucestershire which has an elevation of 110 meters to the North Sea. It has a basin of 12,935 kilometers squared, and has a few meanders making it a mature river. The average discharge in London is 65.8 meters cubes per second (Wikipedia).