This version of HEC-RAS allows the user to fill in a portion of the culvert from the bottom. This option can be applied to any of the culvert shapes. The user is only required to specify the depth to which the culvert bottom is filled in. An example of this is shown in the figure below. The user can also specify a different Manning's n value for the blocked portion of the culvert (the bottom), versus the remainder of the culvert. The user must specify the depth to apply the bottom n value as being equal to the depth of the filled portion of the culvert.
Partially Filled or Buried Culverts