Röthlisberger's study investigates water pressure in intra- and subglacial channels, focusing on the balance between frictional heat from water flow and ice melting, as well as the tendency of channels to close under overburden pressure. Using equilibrium equations, he derives differential equations for steady flow in horizontal, inclined, and vertical channels, considering varying depth, discharge, ice properties, and channel roughness. The results show that pressure decreases with increasing discharge, indicating that water flows through main channels. He also demonstrates that certain glacier lakes form during low discharge and empty during high discharge when the subglacial drainage system's water head drops below the lake level. The study further shows that a uniform ice mass does not float under an inclined bed but can float on a horizontal bed if the ice creep exponent is small. Basal and lateral streams can coexist. Although the theory does not account for time-dependent flow, local topography, ice motion, and sediment load, these factors likely influence actual water flow. Computations were performed for the Gornergletscher, where bed topography and subglacial water pressure data are available. The study concludes that water flows in discrete conduits, forming main arteries, and that the hydraulic grade line (or piezometer line) is crucial for understanding subglacial flow. The analysis also shows that water can flow in channels at the hydraulic grade line, which may be more stable than channels at the bed. The study highlights the importance of understanding subglacial flow dynamics for predicting glacier behavior and water movement within glaciers.Röthlisberger's study investigates water pressure in intra- and subglacial channels, focusing on the balance between frictional heat from water flow and ice melting, as well as the tendency of channels to close under overburden pressure. Using equilibrium equations, he derives differential equations for steady flow in horizontal, inclined, and vertical channels, considering varying depth, discharge, ice properties, and channel roughness. The results show that pressure decreases with increasing discharge, indicating that water flows through main channels. He also demonstrates that certain glacier lakes form during low discharge and empty during high discharge when the subglacial drainage system's water head drops below the lake level. The study further shows that a uniform ice mass does not float under an inclined bed but can float on a horizontal bed if the ice creep exponent is small. Basal and lateral streams can coexist. Although the theory does not account for time-dependent flow, local topography, ice motion, and sediment load, these factors likely influence actual water flow. Computations were performed for the Gornergletscher, where bed topography and subglacial water pressure data are available. The study concludes that water flows in discrete conduits, forming main arteries, and that the hydraulic grade line (or piezometer line) is crucial for understanding subglacial flow. The analysis also shows that water can flow in channels at the hydraulic grade line, which may be more stable than channels at the bed. The study highlights the importance of understanding subglacial flow dynamics for predicting glacier behavior and water movement within glaciers.