The general theory of water flow describes the behavior of water at melting at the base of a glacier or melting ice sheet. It observes the flow of water in the presence of Rothlisberger channels, channels carved upward from the base into the body of the glacier, and Nye channels, or channels cut downward into the bedrock of a glacier bed.
According to the theory, a pressure gradient or difference in the pressure inside the channel versus the pressure in the water prevents the water from being taken up into the Rothlisberger channels, which are not good collectors of water that melts at the base of the glacier.
Rothlisberger presented this theory at the Symposium on the Hydrology of Glaciers, held in Cambridge in 1969, when very little was known about the physical properties of glaciers. Modern methods such as drilling with hot water and other mechanisms for observing glaciers had not been invented. Meteorologists had only recently observed the phenomena of water moving within glaciers and glaciers storing and releasing water according to seasonal timetables in glacial basins. These were revolutionary concepts at the time.
Rothlisberger's theory, which is still valid, offered one of the first insights into the inner workings of glaciers and helped give rise to the emerging science of glacier hydrology.