(alinement, drainage, foundation, surface) (4-14)
In Section III, obstructions are listed and described. The five types of obstructions we learned about in Lesson
3 are reported here when they occur, located by grid coordinates, with reference to additional reports when
Section III of the Road Reconnaissance Report contains a list of ____________________________________ .
Underbridge clearance, shown in Column 4, is the minimum clear distance between the underside of the
bridge and the surface of the ground or water at mean level. Mean water level can be determined from gaging-
station records, observation of high and low water marks, or information gained from local inhabitants.
The distance between the underside of the bridge and the surface of the ground or water below, called the
__________________________ ______________________ , is entered in Column ______________________ .