To use HEC-RAS software to figure out how high floodwaters will go, what key information do you need about the river's shape?

To use HEC-RAS software to calculate floodwater heights, you need comprehensive geometric information about the river's shape, primarily derived from cross-sectional data, longitudinal connectivity, and any hydraulic structures present. The most critical data comes from cross-sections, which are detailed profiles of the river channel and its adjacent floodplains, taken perpendicular to the direction of flow at various points along the river. Each cross-section is defined by a series of station-elevation points. A 'station' represents the horizontal distance from a reference point, often the far left bank looking downstream, while 'elevation' is the vertical height above a common datum, such as sea level. These points precisely map the bed of the river, the banks, and the surroun....