Rivers are rather like the high-voltage transmission lines that cross the landscape. Just as power lines transport the energy produced at power stations, which is then transformed into work by its use, so too are rivers transporters of energy. The river gains its energy from the head derived from the elevation difference between its upper and lower reaches-a change from potential to kinetic energy. The water in its channel, along with its sediment load, transforms this energy into work, which in turn produces fluvial landforms along the entire length of its channel. The combination of water and sediment is what makes rivers geomorphological agents. Water is an essential agent of sediment transport, and the fluvial landforms derived from these sediments create a riverine environment in which the river is dynamically adjusted.