the location on a river of the cross section chosen to measure the river’s discharge and load. The cross section is perpendicular to the usual direction of flow on a segment of the river where there are no bends and where the channel has a more or less well-defined trough-shaped bottom. The segment must be devoid of shoals, islands, and tributaries so that there will be no disturbances in the uniformity of the flow. The site must monitor the total discharge, including the flow of the main streams, the tributaries, and floodplains. The discharge measured at the site is related to the river’s stage, which is simultaneously measured on a fixed gauge positioned either at the site or in the immediate vicinity.