What do the curving broken lines on a grading plan represent?

The curving broken lines on a grading plan represent contour lines. Contour lines are used to illustrate the elevation and slope of the land. They connect points of equal elevation and help in visualizing the terrain's shape and gradient. By analyzing these lines, a contractor can determine how water drainage will behave and how to grade the land appropriately for construction.

Understanding contour lines is crucial for ensuring that the land is shaped properly for any proposed structures, as improper grading can lead to drainage problems and other site issues. In contrast, property lines define the boundaries of a lot, elevation markers indicate specific heights or depths at particular points, and design layout is more concerned with the overall plan for structures and landscaping rather than the existing topography.